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e4787e71 |
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16-Jun-2022 |
Rashmica Gupta <rashmica@linux.ibm.com> |
powerpc/signal: Update comment for clarity The comment being referred to was deleted in commit af1bbc3dd3d5 ("powerpc: Remove UP only lazy floating point and vector optimisations"). Add a bit more detail so it's clear why we need to clear the FP/VEC/VSX bits here. Signed-off-by: Rashmica Gupta <rashmica@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20220617043135.426897-1-rashmica@linux.ibm.com
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2896b2df |
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07-Mar-2022 |
Nicholas Piggin <npiggin@gmail.com> |
powerpc/signal: Report minimum signal frame size to userspace via AT_MINSIGSTKSZ Implement the AT_MINSIGSTKSZ AUXV entry, allowing userspace to dynamically size stack allocations in a manner forward-compatible with new processor state saved in the signal frame For now these statically find the maximum signal frame size rather than doing any runtime testing of features to minimise the size. glibc 2.34 will take advantage of this, as will applications that use use _SC_MINSIGSTKSZ and _SC_SIGSTKSZ. Reviewed-by: Tulio Magno Quites Machado Filho <tuliom@linux.ibm.com> Signed-off-by: Nicholas Piggin <npiggin@gmail.com> References: 94b07c1f8c39 ("arm64: signal: Report signal frame size to userspace via auxv") Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20220307182734.289289-2-npiggin@gmail.com
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1fd02f66 |
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30-Apr-2022 |
Julia Lawall <Julia.Lawall@inria.fr> |
powerpc: fix typos in comments Various spelling mistakes in comments. Detected with the help of Coccinelle. Signed-off-by: Julia Lawall <Julia.Lawall@inria.fr> Reviewed-by: Joel Stanley <joel@jms.id.au> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20220430185654.5855-1-Julia.Lawall@inria.fr
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5b23cb8c |
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15-Feb-2022 |
Christophe Leroy <christophe.leroy@csgroup.eu> |
powerpc: Move and rename func_descr_t There are three architectures with function descriptors, try to have common names for the address they contain in order to refactor some functions into generic functions later. powerpc has 'entry' ia64 has 'ip' parisc has 'addr' Vote for 'addr' and update 'func_descr_t' accordingly. Move it in asm/elf.h to have it at the same place on all three architectures, remove the typedef which hides its real type, and change it to a smoother name 'struct func_desc'. Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Reviewed-by: Nicholas Piggin <npiggin@gmail.com> Reviewed-by: Kees Cook <keescook@chromium.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/529b2ba1d001e8f628ef0d30e8044c9b3d0a4921.1644928018.git.christophe.leroy@csgroup.eu
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fcb116bc |
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18-Nov-2021 |
Eric W. Biederman <ebiederm@xmission.com> |
signal: Replace force_fatal_sig with force_exit_sig when in doubt Recently to prevent issues with SECCOMP_RET_KILL and similar signals being changed before they are delivered SA_IMMUTABLE was added. Unfortunately this broke debuggers[1][2] which reasonably expect to be able to trap synchronous SIGTRAP and SIGSEGV even when the target process is not configured to handle those signals. Add force_exit_sig and use it instead of force_fatal_sig where historically the code has directly called do_exit. This has the implementation benefits of going through the signal exit path (including generating core dumps) without the danger of allowing userspace to ignore or change these signals. This avoids userspace regressions as older kernels exited with do_exit which debuggers also can not intercept. In the future is should be possible to improve the quality of implementation of the kernel by changing some of these force_exit_sig calls to force_fatal_sig. That can be done where it matters on a case-by-case basis with careful analysis. Reported-by: Kyle Huey <me@kylehuey.com> Reported-by: kernel test robot <oliver.sang@intel.com> [1] https://lkml.kernel.org/r/CAP045AoMY4xf8aC_4QU_-j7obuEPYgTcnQQP3Yxk=2X90jtpjw@mail.gmail.com [2] https://lkml.kernel.org/r/20211117150258.GB5403@xsang-OptiPlex-9020 Fixes: 00b06da29cf9 ("signal: Add SA_IMMUTABLE to ensure forced siganls do not get changed") Fixes: a3616a3c0272 ("signal/m68k: Use force_sigsegv(SIGSEGV) in fpsp040_die") Fixes: 83a1f27ad773 ("signal/powerpc: On swapcontext failure force SIGSEGV") Fixes: 9bc508cf0791 ("signal/s390: Use force_sigsegv in default_trap_handler") Fixes: 086ec444f866 ("signal/sparc32: In setup_rt_frame and setup_fram use force_fatal_sig") Fixes: c317d306d550 ("signal/sparc32: Exit with a fatal signal when try_to_clear_window_buffer fails") Fixes: 695dd0d634df ("signal/x86: In emulate_vsyscall force a signal instead of calling do_exit") Fixes: 1fbd60df8a85 ("signal/vm86_32: Properly send SIGSEGV when the vm86 state cannot be saved.") Fixes: 941edc5bf174 ("exit/syscall_user_dispatch: Send ordinary signals on failure") Link: https://lkml.kernel.org/r/871r3dqfv8.fsf_-_@email.froward.int.ebiederm.org Reviewed-by: Kees Cook <keescook@chromium.org> Tested-by: Kees Cook <keescook@chromium.org> Tested-by: Kyle Huey <khuey@kylehuey.com> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
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e21294a7 |
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25-Oct-2021 |
Eric W. Biederman <ebiederm@xmission.com> |
signal: Replace force_sigsegv(SIGSEGV) with force_fatal_sig(SIGSEGV) Now that force_fatal_sig exists it is unnecessary and a bit confusing to use force_sigsegv in cases where the simpler force_fatal_sig is wanted. So change every instance we can to make the code clearer. Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org> Link: https://lkml.kernel.org/r/877de7jrev.fsf@disp2133 Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
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83a1f27a |
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19-Oct-2021 |
Eric W. Biederman <ebiederm@xmission.com> |
signal/powerpc: On swapcontext failure force SIGSEGV If the register state may be partial and corrupted instead of calling do_exit, call force_sigsegv(SIGSEGV). Which properly kills the process with SIGSEGV and does not let any more userspace code execute, instead of just killing one thread of the process and potentially confusing everything. Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: linuxppc-dev@lists.ozlabs.org History-tree: git://git.kernel.org/pub/scm/linux/kernel/git/tglx/history.git Fixes: 756f1ae8a44e ("PPC32: Rework signal code and add a swapcontext system call.") Fixes: 04879b04bf50 ("[PATCH] ppc64: VMX (Altivec) support & signal32 rework, from Ben Herrenschmidt") Link: https://lkml.kernel.org/r/20211020174406.17889-7-ebiederm@xmission.com Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
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bb523b40 |
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02-Aug-2021 |
Andreas Gruenbacher <agruenba@redhat.com> |
gup: Turn fault_in_pages_{readable,writeable} into fault_in_{readable,writeable} Turn fault_in_pages_{readable,writeable} into versions that return the number of bytes not faulted in, similar to copy_to_user, instead of returning a non-zero value when any of the requested pages couldn't be faulted in. This supports the existing users that require all pages to be faulted in as well as new users that are happy if any pages can be faulted in. Rename the functions to fault_in_{readable,writeable} to make sure this change doesn't silently break things. Neither of these functions is entirely trivial and it doesn't seem useful to inline them, so move them to mm/gup.c. Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
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59dc5bfc |
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17-Jun-2021 |
Nicholas Piggin <npiggin@gmail.com> |
powerpc/64s: avoid reloading (H)SRR registers if they are still valid When an interrupt is taken, the SRR registers are set to return to where it left off. Unless they are modified in the meantime, or the return address or MSR are modified, there is no need to reload these registers when returning from interrupt. Introduce per-CPU flags that track the validity of SRR and HSRR registers. These are cleared when returning from interrupt, when using the registers for something else (e.g., OPAL calls), when adjusting the return address or MSR of a context, and when context switching (which changes the return address and MSR). This improves the performance of interrupt returns. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> [mpe: Fold in fixup patch from Nick] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210617155116.2167984-5-npiggin@gmail.com
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a3309226 |
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10-Jun-2021 |
Michael Ellerman <mpe@ellerman.id.au> |
powerpc/signal64: Don't read sigaction arguments back from user memory When delivering a signal to a sigaction style handler (SA_SIGINFO), we pass pointers to the siginfo and ucontext via r4 and r5. Currently we populate the values in those registers by reading the pointers out of the sigframe in user memory, even though the values in user memory were written by the kernel just prior: unsafe_put_user(&frame->info, &frame->pinfo, badframe_block); unsafe_put_user(&frame->uc, &frame->puc, badframe_block); ... if (ksig->ka.sa.sa_flags & SA_SIGINFO) { err |= get_user(regs->gpr[4], (unsigned long __user *)&frame->pinfo); err |= get_user(regs->gpr[5], (unsigned long __user *)&frame->puc); ie. we write &frame->info into frame->pinfo, and then read frame->pinfo back into r4, and similarly for &frame->uc. The code has always been like this, since linux-fullhistory commit d4f2d95eca2c ("Forward port of 2.4 ppc64 signal changes."). There's no reason for us to read the values back from user memory, rather than just setting the value in the gpr[4/5] directly. In fact reading the value back from user memory opens up the possibility of another user thread changing the values before we read them back. Although any process doing that would be racing against the kernel delivering the signal, and would risk corrupting the stack, so that would be a userspace bug. Note that this is 64-bit only code, so there's no subtlety with the size of pointers differing between kernel and user. Also the frame variable is not modified to point elsewhere during the function. In the past reading the values back from user memory was not costly, but now that we have KUAP on some CPUs it is, so we'd rather avoid it for that reason too. So change the code to just set the values directly, using the same values we have written to the sigframe previously in the function. Note also that this matches what our 32-bit signal code does. Using a version of will-it-scale's signal1_threads that sets SA_SIGINFO, this results in a ~4% increase in signals per second on a Power9, from 229,777 to 239,766. Reviewed-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210610072949.3198522-1-mpe@ellerman.id.au
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1c9debbc |
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20-May-2021 |
Christophe Leroy <christophe.leroy@csgroup.eu> |
powerpc/signal: Use PPC_RAW_xx() macros To improve readability, use PPC_RAW_xx() macros instead of open coding. Those macros are self-explanatory so the comments can go as well. Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/4ca2bfdca2f47a293d05f61eb3c4e487ee170f1f.1621506159.git.christophe.leroy@csgroup.eu
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e41d6c3f |
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08-Jun-2021 |
Michael Ellerman <mpe@ellerman.id.au> |
powerpc/signal64: Copy siginfo before changing regs->nip In commit 96d7a4e06fab ("powerpc/signal64: Rewrite handle_rt_signal64() to minimise uaccess switches") the 64-bit signal code was rearranged to use user_write_access_begin/end(). As part of that change the call to copy_siginfo_to_user() was moved later in the function, so that it could be done after the user_write_access_end(). In particular it was moved after we modify regs->nip to point to the signal trampoline. That means if copy_siginfo_to_user() fails we exit handle_rt_signal64() with an error but with regs->nip modified, whereas previously we would not modify regs->nip until the copy succeeded. Returning an error from signal delivery but with regs->nip updated leaves the process in a sort of half-delivered state. We do immediately force a SEGV in signal_setup_done(), called from do_signal(), so the process should never run in the half-delivered state. However that SEGV is not delivered until we've gone around to do_notify_resume() again, so it's possible some tracing could observe the half-delivered state. There are other cases where we fail signal delivery with regs partly updated, eg. the write to newsp and SA_SIGINFO, but the latter at least is very unlikely to fail as it reads back from the frame we just wrote to. Looking at other arches they seem to be more careful about leaving regs unchanged until the copy operations have succeeded, and in general that seems like good hygenie. So although the current behaviour is not cleary buggy, it's also not clearly correct. So move the call to copy_siginfo_to_user() up prior to the modification of regs->nip, which is closer to the old behaviour, and easier to reason about. Fixes: 96d7a4e06fab ("powerpc/signal64: Rewrite handle_rt_signal64() to minimise uaccess switches") Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210608134605.2783677-1-mpe@ellerman.id.au
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8dc7f022 |
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16-Mar-2021 |
Nicholas Piggin <npiggin@gmail.com> |
powerpc: remove partial register save logic All subarchitectures always save all GPRs to pt_regs interrupt frames now. Remove FULL_REGS and associated bits. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210316104206.407354-11-npiggin@gmail.com
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d3ccc978 |
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26-Feb-2021 |
Christopher M. Riedl <cmr@codefail.de> |
powerpc/signal: Use __get_user() to copy sigset_t Usually sigset_t is exactly 8B which is a "trivial" size and does not warrant using __copy_from_user(). Use __get_user() directly in anticipation of future work to remove the trivial size optimizations from __copy_from_user(). The ppc32 implementation of get_sigset_t() previously called copy_from_user() which, unlike __copy_from_user(), calls access_ok(). Replacing this w/ __get_user() (no access_ok()) is fine here since both callsites in signal_32.c are preceded by an earlier access_ok(). Signed-off-by: Christopher M. Riedl <cmr@codefail.de> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210227011259.11992-11-cmr@codefail.de
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0f92433b |
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26-Feb-2021 |
Daniel Axtens <dja@axtens.net> |
powerpc/signal64: Rewrite rt_sigreturn() to minimise uaccess switches Add uaccess blocks and use the 'unsafe' versions of functions doing user access where possible to reduce the number of times uaccess has to be opened/closed. Co-developed-by: Christopher M. Riedl <cmr@codefail.de> Signed-off-by: Daniel Axtens <dja@axtens.net> Signed-off-by: Christopher M. Riedl <cmr@codefail.de> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210227011259.11992-10-cmr@codefail.de
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96d7a4e0 |
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26-Feb-2021 |
Daniel Axtens <dja@axtens.net> |
powerpc/signal64: Rewrite handle_rt_signal64() to minimise uaccess switches Add uaccess blocks and use the 'unsafe' versions of functions doing user access where possible to reduce the number of times uaccess has to be opened/closed. There is no 'unsafe' version of copy_siginfo_to_user, so move it slightly to allow for a "longer" uaccess block. Co-developed-by: Christopher M. Riedl <cmr@codefail.de> Signed-off-by: Daniel Axtens <dja@axtens.net> Signed-off-by: Christopher M. Riedl <cmr@codefail.de> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210227011259.11992-9-cmr@codefail.de
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193323e1 |
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26-Feb-2021 |
Christopher M. Riedl <cmr@codefail.de> |
powerpc/signal64: Replace restore_sigcontext() w/ unsafe_restore_sigcontext() Previously restore_sigcontext() performed a costly KUAP switch on every uaccess operation. These repeated uaccess switches cause a significant drop in signal handling performance. Rewrite restore_sigcontext() to assume that a userspace read access window is open by replacing all uaccess functions with their 'unsafe' versions. Modify the callers to first open, call unsafe_restore_sigcontext(), and then close the uaccess window. Signed-off-by: Christopher M. Riedl <cmr@codefail.de> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210227011259.11992-8-cmr@codefail.de
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7bb081c8 |
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26-Feb-2021 |
Christopher M. Riedl <cmr@codefail.de> |
powerpc/signal64: Replace setup_sigcontext() w/ unsafe_setup_sigcontext() Previously setup_sigcontext() performed a costly KUAP switch on every uaccess operation. These repeated uaccess switches cause a significant drop in signal handling performance. Rewrite setup_sigcontext() to assume that a userspace write access window is open by replacing all uaccess functions with their 'unsafe' versions. Modify the callers to first open, call unsafe_setup_sigcontext() and then close the uaccess window. Signed-off-by: Christopher M. Riedl <cmr@codefail.de> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210227011259.11992-7-cmr@codefail.de
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2d19630e |
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26-Feb-2021 |
Christopher M. Riedl <cmr@codefail.de> |
powerpc/signal64: Remove TM ifdefery in middle of if/else block Both rt_sigreturn() and handle_rt_signal_64() contain TM-related ifdefs which break-up an if/else block. Provide stubs for the ifdef-guarded TM functions and remove the need for an ifdef in rt_sigreturn(). Rework the remaining TM ifdef in handle_rt_signal64() similar to commit f1cf4f93de2f ("powerpc/signal32: Remove ifdefery in middle of if/else"). Unlike in the commit for ppc32, the ifdef can't be removed entirely since uc_transact in sigframe depends on CONFIG_PPC_TRANSACTIONAL_MEM. Signed-off-by: Christopher M. Riedl <cmr@codefail.de> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210227011259.11992-6-cmr@codefail.de
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c6c9645e |
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26-Feb-2021 |
Christopher M. Riedl <cmr@codefail.de> |
powerpc/signal64: Remove non-inline calls from setup_sigcontext() The majority of setup_sigcontext() can be refactored to execute in an "unsafe" context assuming an open uaccess window except for some non-inline function calls. Move these out into a separate prepare_setup_sigcontext() function which must be called first and before opening up a uaccess window. Non-inline function calls should be avoided during a uaccess window for a few reasons: - KUAP should be enabled for as much kernel code as possible. Opening a uaccess window disables KUAP which means any code executed during this time contributes to a potential attack surface. - Non-inline functions default to traceable which means they are instrumented for ftrace. This adds more code which could run with KUAP disabled. - Powerpc does not currently support the objtool UACCESS checks. All code running with uaccess must be audited manually which means: less code -> less work -> fewer problems (in theory). A follow-up commit converts setup_sigcontext() to be "unsafe". Signed-off-by: Christopher M. Riedl <cmr@codefail.de> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210227011259.11992-4-cmr@codefail.de
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91bf6955 |
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27-Sep-2020 |
Christophe Leroy <christophe.leroy@csgroup.eu> |
powerpc/vdso: Retrieve sigtramp offsets at buildtime This is copied from arm64. Instead of using runtime generated signal trampoline offsets, get offsets at buildtime. If the said trampoline doesn't exist, build will fail. So no need to check whether the trampoline exists or not in the VDSO. Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/f8bfd6812c3e3678b1cdb4d55a52f9eb022b40d3.1601197618.git.christophe.leroy@csgroup.eu
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c102f076 |
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27-Sep-2020 |
Christophe Leroy <christophe.leroy@csgroup.eu> |
powerpc/vdso: Replace vdso_base by vdso All other architectures but s390 use a void pointer named 'vdso' to reference the VDSO mapping. In a following patch, the VDSO data page will be put in front of text, vdso_base will then not anymore point to VDSO text. To avoid confusion between vdso_base and VDSO text, rename vdso_base into vdso and make it a void __user *. Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/8e6cefe474aa4ceba028abb729485cd46c140990.1601197618.git.christophe.leroy@csgroup.eu
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7fe8f773 |
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18-Aug-2020 |
Christophe Leroy <christophe.leroy@csgroup.eu> |
powerpc/signal: Refactor bad frame logging The logging of bad frame appears half a dozen of times and is pretty similar. Create signal_fault() fonction to perform that logging. Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/fa094445c119fc00315e1c13783b493346306c6a.1597770847.git.christophe.leroy@csgroup.eu
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c180cb30 |
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18-Aug-2020 |
Christophe Leroy <christophe.leroy@csgroup.eu> |
powerpc/signal: Call get_tm_stackpointer() from get_sigframe() Instead of calling get_tm_stackpointer() from the caller, call it directly from get_sigframe(). This avoids a double call and allows get_tm_stackpointer() to become static and be inlined into get_sigframe() by GCC. Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/abfdc105b8b28c4eb3ab9a26297d17f302b600ea.1597770847.git.christophe.leroy@csgroup.eu
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454b1abb |
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18-Aug-2020 |
Christophe Leroy <christophe.leroy@csgroup.eu> |
powerpc/signal: Move access_ok() out of get_sigframe() This access_ok() will soon be performed by user_access_begin(). So move it out of get_sigframe(). Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/900b93744732ed0887f28f5b6a40730fb04a43fa.1597770847.git.christophe.leroy@csgroup.eu
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3fcfb5d1 |
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18-Aug-2020 |
Christophe Leroy <christophe.leroy@csgroup.eu> |
powerpc/signal: Remove BUG_ON() in handler_signal functions There is already the same BUG_ON() check in do_signal() which is the only caller of handle_rt_signal64() handle_rt_signal32() and handle_signal32(). Remove those three redundant BUG_ON(). Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/3582e10a341d523c9c3f1ac925c3aaefc9d9293d.1597770847.git.christophe.leroy@csgroup.eu
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96032f98 |
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07-Jul-2020 |
Christophe Leroy <christophe.leroy@csgroup.eu> |
powerpc/signal64: Don't opencode page prefaulting Instead of doing a __get_user() from the first and last location into a tmp var which won't be used, use fault_in_pages_readable() Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/810bd8840ef990a200f58c9dea9abe767ca02a3a.1594146723.git.christophe.leroy@csgroup.eu
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0138ba57 |
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11-May-2020 |
Nicholas Piggin <npiggin@gmail.com> |
powerpc/64/signal: Balance return predictor stack in signal trampoline Returning from an interrupt or syscall to a signal handler currently begins execution directly at the handler's entry point, with LR set to the address of the sigreturn trampoline. When the signal handler function returns, it runs the trampoline. It looks like this: # interrupt at user address xyz # kernel stuff... signal is raised rfid # void handler(int sig) addis 2,12,.TOC.-.LCF0@ha addi 2,2,.TOC.-.LCF0@l mflr 0 std 0,16(1) stdu 1,-96(1) # handler stuff ld 0,16(1) mtlr 0 blr # __kernel_sigtramp_rt64 addi r1,r1,__SIGNAL_FRAMESIZE li r0,__NR_rt_sigreturn sc # kernel executes rt_sigreturn rfid # back to user address xyz Note the blr with no matching bl. This can corrupt the return predictor. Solve this by instead resuming execution at the signal trampoline which then calls the signal handler. qtrace-tools link_stack checker confirms the entire user/kernel/vdso cycle is balanced after this patch, whereas it's not upstream. Alan confirms the dwarf unwind info still looks good. gdb still recognises the signal frame and can step into parent frames if it break inside a signal handler. Performance is pretty noisy, not a very significant change on a POWER9 here, but branch misses are consistently a lot lower on a microbenchmark: Performance counter stats for './signal': 13,085.72 msec task-clock # 1.000 CPUs utilized 45,024,760,101 cycles # 3.441 GHz 65,102,895,542 instructions # 1.45 insn per cycle 11,271,673,787 branches # 861.372 M/sec 59,468,979 branch-misses # 0.53% of all branches 12,989.09 msec task-clock # 1.000 CPUs utilized 44,692,719,559 cycles # 3.441 GHz 65,109,984,964 instructions # 1.46 insn per cycle 11,282,136,057 branches # 868.585 M/sec 39,786,942 branch-misses # 0.35% of all branches Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20200511101952.1463138-1-npiggin@gmail.com
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e31cf2f4 |
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08-Jun-2020 |
Mike Rapoport <rppt@kernel.org> |
mm: don't include asm/pgtable.h if linux/mm.h is already included Patch series "mm: consolidate definitions of page table accessors", v2. The low level page table accessors (pXY_index(), pXY_offset()) are duplicated across all architectures and sometimes more than once. For instance, we have 31 definition of pgd_offset() for 25 supported architectures. Most of these definitions are actually identical and typically it boils down to, e.g. static inline unsigned long pmd_index(unsigned long address) { return (address >> PMD_SHIFT) & (PTRS_PER_PMD - 1); } static inline pmd_t *pmd_offset(pud_t *pud, unsigned long address) { return (pmd_t *)pud_page_vaddr(*pud) + pmd_index(address); } These definitions can be shared among 90% of the arches provided XYZ_SHIFT, PTRS_PER_XYZ and xyz_page_vaddr() are defined. For architectures that really need a custom version there is always possibility to override the generic version with the usual ifdefs magic. These patches introduce include/linux/pgtable.h that replaces include/asm-generic/pgtable.h and add the definitions of the page table accessors to the new header. This patch (of 12): The linux/mm.h header includes <asm/pgtable.h> to allow inlining of the functions involving page table manipulations, e.g. pte_alloc() and pmd_alloc(). So, there is no point to explicitly include <asm/pgtable.h> in the files that include <linux/mm.h>. The include statements in such cases are remove with a simple loop: for f in $(git grep -l "include <linux/mm.h>") ; do sed -i -e '/include <asm\/pgtable.h>/ d' $f done Signed-off-by: Mike Rapoport <rppt@linux.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Cain <bcain@codeaurora.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Chris Zankel <chris@zankel.net> Cc: "David S. Miller" <davem@davemloft.net> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Greentime Hu <green.hu@gmail.com> Cc: Greg Ungerer <gerg@linux-m68k.org> Cc: Guan Xuetao <gxt@pku.edu.cn> Cc: Guo Ren <guoren@kernel.org> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Helge Deller <deller@gmx.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: Ley Foon Tan <ley.foon.tan@intel.com> Cc: Mark Salter <msalter@redhat.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Matt Turner <mattst88@gmail.com> Cc: Max Filippov <jcmvbkbc@gmail.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Michal Simek <monstr@monstr.eu> Cc: Mike Rapoport <rppt@kernel.org> Cc: Nick Hu <nickhu@andestech.com> Cc: Paul Walmsley <paul.walmsley@sifive.com> Cc: Richard Weinberger <richard@nod.at> Cc: Rich Felker <dalias@libc.org> Cc: Russell King <linux@armlinux.org.uk> Cc: Stafford Horne <shorne@gmail.com> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tony Luck <tony.luck@intel.com> Cc: Vincent Chen <deanbo422@gmail.com> Cc: Vineet Gupta <vgupta@synopsys.com> Cc: Will Deacon <will@kernel.org> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Link: http://lkml.kernel.org/r/20200514170327.31389-1-rppt@kernel.org Link: http://lkml.kernel.org/r/20200514170327.31389-2-rppt@kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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4e0e45b0 |
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07-May-2020 |
Nicholas Piggin <npiggin@gmail.com> |
powerpc: Use trap metadata to prevent double restart rather than zeroing trap It's not very nice to zero trap for this, because then system calls no longer have trap_is_syscall(regs) invariant, and we can't distinguish between sc and scv system calls (in a later patch). Take one last unused bit from the low bits of the pt_regs.trap word for this instead. There is not a really good reason why it should be in trap as opposed to another field, but trap has some concept of flags and it exists. Ideally I think we would move trap to 2-byte field and have 2 more bytes available independently. Add a selftests case for this, which can be seen to fail if trap_norestart() is changed to return false. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> [mpe: Make them static inlines] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20200507121332.2233629-4-mpe@ellerman.id.au
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#
c7def7fb |
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31-Mar-2020 |
Michael Ellerman <mpe@ellerman.id.au> |
powerpc/64/tm: Don't let userspace set regs->trap via sigreturn In restore_tm_sigcontexts() we take the trap value directly from the user sigcontext with no checking: err |= __get_user(regs->trap, &sc->gp_regs[PT_TRAP]); This means we can be in the kernel with an arbitrary regs->trap value. Although that's not immediately problematic, there is a risk we could trigger one of the uses of CHECK_FULL_REGS(): #define CHECK_FULL_REGS(regs) BUG_ON(regs->trap & 1) It can also cause us to unnecessarily save non-volatile GPRs again in save_nvgprs(), which shouldn't be problematic but is still wrong. It's also possible it could trick the syscall restart machinery, which relies on regs->trap not being == 0xc00 (see 9a81c16b5275 ("powerpc: fix double syscall restarts")), though I haven't been able to make that happen. Finally it doesn't match the behaviour of the non-TM case, in restore_sigcontext() which zeroes regs->trap. So change restore_tm_sigcontexts() to zero regs->trap. This was discovered while testing Nick's upcoming rewrite of the syscall entry path. In that series the call to save_nvgprs() prior to signal handling (do_notify_resume()) is removed, which leaves the low-bit of regs->trap uncleared which can then trigger the FULL_REGS() WARNs in setup_tm_sigcontexts(). Fixes: 2b0a576d15e0 ("powerpc: Add new transactional memory state to the signal context") Cc: stable@vger.kernel.org # v3.9+ Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20200401023836.3286664-1-mpe@ellerman.id.au
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#
2464cc4c |
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10-Feb-2020 |
Gustavo Luiz Duarte <gustavold@linux.ibm.com> |
powerpc/tm: Fix clearing MSR[TS] in current when reclaiming on signal delivery After a treclaim, we expect to be in non-transactional state. If we don't clear the current thread's MSR[TS] before we get preempted, then tm_recheckpoint_new_task() will recheckpoint and we get rescheduled in suspended transaction state. When handling a signal caught in transactional state, handle_rt_signal64() calls get_tm_stackpointer() that treclaims the transaction using tm_reclaim_current() but without clearing the thread's MSR[TS]. This can cause the TM Bad Thing exception below if later we pagefault and get preempted trying to access the user's sigframe, using __put_user(). Afterwards, when we are rescheduled back into do_page_fault() (but now in suspended state since the thread's MSR[TS] was not cleared), upon executing 'rfid' after completion of the page fault handling, the exception is raised because a transition from suspended to non-transactional state is invalid. Unexpected TM Bad Thing exception at c00000000000de44 (msr 0x8000000302a03031) tm_scratch=800000010280b033 Oops: Unrecoverable exception, sig: 6 [#1] LE PAGE_SIZE=64K MMU=Hash SMP NR_CPUS=2048 NUMA pSeries CPU: 25 PID: 15547 Comm: a.out Not tainted 5.4.0-rc2 #32 NIP: c00000000000de44 LR: c000000000034728 CTR: 0000000000000000 REGS: c00000003fe7bd70 TRAP: 0700 Not tainted (5.4.0-rc2) MSR: 8000000302a03031 <SF,VEC,VSX,FP,ME,IR,DR,LE,TM[SE]> CR: 44000884 XER: 00000000 CFAR: c00000000000dda4 IRQMASK: 0 PACATMSCRATCH: 800000010280b033 GPR00: c000000000034728 c000000f65a17c80 c000000001662800 00007fffacf3fd78 GPR04: 0000000000001000 0000000000001000 0000000000000000 c000000f611f8af0 GPR08: 0000000000000000 0000000078006001 0000000000000000 000c000000000000 GPR12: c000000f611f84b0 c00000003ffcb200 0000000000000000 0000000000000000 GPR16: 0000000000000000 0000000000000000 0000000000000000 0000000000000000 GPR20: 0000000000000000 0000000000000000 0000000000000000 c000000f611f8140 GPR24: 0000000000000000 00007fffacf3fd68 c000000f65a17d90 c000000f611f7800 GPR28: c000000f65a17e90 c000000f65a17e90 c000000001685e18 00007fffacf3f000 NIP [c00000000000de44] fast_exception_return+0xf4/0x1b0 LR [c000000000034728] handle_rt_signal64+0x78/0xc50 Call Trace: [c000000f65a17c80] [c000000000034710] handle_rt_signal64+0x60/0xc50 (unreliable) [c000000f65a17d30] [c000000000023640] do_notify_resume+0x330/0x460 [c000000f65a17e20] [c00000000000dcc4] ret_from_except_lite+0x70/0x74 Instruction dump: 7c4ff120 e8410170 7c5a03a6 38400000 f8410060 e8010070 e8410080 e8610088 60000000 60000000 e8810090 e8210078 <4c000024> 48000000 e8610178 88ed0989 ---[ end trace 93094aa44b442f87 ]--- The simplified sequence of events that triggers the above exception is: ... # userspace in NON-TRANSACTIONAL state tbegin # userspace in TRANSACTIONAL state signal delivery # kernelspace in SUSPENDED state handle_rt_signal64() get_tm_stackpointer() treclaim # kernelspace in NON-TRANSACTIONAL state __put_user() page fault happens. We will never get back here because of the TM Bad Thing exception. page fault handling kicks in and we voluntarily preempt ourselves do_page_fault() __schedule() __switch_to(other_task) our task is rescheduled and we recheckpoint because the thread's MSR[TS] was not cleared __switch_to(our_task) switch_to_tm() tm_recheckpoint_new_task() trechkpt # kernelspace in SUSPENDED state The page fault handling resumes, but now we are in suspended transaction state do_page_fault() completes rfid <----- trying to get back where the page fault happened (we were non-transactional back then) TM Bad Thing # illegal transition from suspended to non-transactional This patch fixes that issue by clearing the current thread's MSR[TS] just after treclaim in get_tm_stackpointer() so that we stay in non-transactional state in case we are preempted. In order to make treclaim and clearing the thread's MSR[TS] atomic from a preemption perspective when CONFIG_PREEMPT is set, preempt_disable/enable() is used. It's also necessary to save the previous value of the thread's MSR before get_tm_stackpointer() is called so that it can be exposed to the signal handler later in setup_tm_sigcontexts() to inform the userspace MSR at the moment of the signal delivery. Found with tm-signal-context-force-tm kernel selftest. Fixes: 2b0a576d15e0 ("powerpc: Add new transactional memory state to the signal context") Cc: stable@vger.kernel.org # v3.9 Signed-off-by: Gustavo Luiz Duarte <gustavold@linux.ibm.com> Acked-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20200211033831.11165-1-gustavold@linux.ibm.com
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#
f16d80b7 |
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18-Jul-2019 |
Michael Neuling <mikey@neuling.org> |
powerpc/tm: Fix oops on sigreturn on systems without TM On systems like P9 powernv where we have no TM (or P8 booted with ppc_tm=off), userspace can construct a signal context which still has the MSR TS bits set. The kernel tries to restore this context which results in the following crash: Unexpected TM Bad Thing exception at c0000000000022fc (msr 0x8000000102a03031) tm_scratch=800000020280f033 Oops: Unrecoverable exception, sig: 6 [#1] LE PAGE_SIZE=64K MMU=Hash SMP NR_CPUS=2048 NUMA pSeries Modules linked in: CPU: 0 PID: 1636 Comm: sigfuz Not tainted 5.2.0-11043-g0a8ad0ffa4 #69 NIP: c0000000000022fc LR: 00007fffb2d67e48 CTR: 0000000000000000 REGS: c00000003fffbd70 TRAP: 0700 Not tainted (5.2.0-11045-g7142b497d8) MSR: 8000000102a03031 <SF,VEC,VSX,FP,ME,IR,DR,LE,TM[E]> CR: 42004242 XER: 00000000 CFAR: c0000000000022e0 IRQMASK: 0 GPR00: 0000000000000072 00007fffb2b6e560 00007fffb2d87f00 0000000000000669 GPR04: 00007fffb2b6e728 0000000000000000 0000000000000000 00007fffb2b6f2a8 GPR08: 0000000000000000 0000000000000000 0000000000000000 0000000000000000 GPR12: 0000000000000000 00007fffb2b76900 0000000000000000 0000000000000000 GPR16: 00007fffb2370000 00007fffb2d84390 00007fffea3a15ac 000001000a250420 GPR20: 00007fffb2b6f260 0000000010001770 0000000000000000 0000000000000000 GPR24: 00007fffb2d843a0 00007fffea3a14a0 0000000000010000 0000000000800000 GPR28: 00007fffea3a14d8 00000000003d0f00 0000000000000000 00007fffb2b6e728 NIP [c0000000000022fc] rfi_flush_fallback+0x7c/0x80 LR [00007fffb2d67e48] 0x7fffb2d67e48 Call Trace: Instruction dump: e96a0220 e96a02a8 e96a0330 e96a03b8 394a0400 4200ffdc 7d2903a6 e92d0c00 e94d0c08 e96d0c10 e82d0c18 7db242a6 <4c000024> 7db243a6 7db142a6 f82d0c18 The problem is the signal code assumes TM is enabled when CONFIG_PPC_TRANSACTIONAL_MEM is enabled. This may not be the case as with P9 powernv or if `ppc_tm=off` is used on P8. This means any local user can crash the system. Fix the problem by returning a bad stack frame to the user if they try to set the MSR TS bits with sigreturn() on systems where TM is not supported. Found with sigfuz kernel selftest on P9. This fixes CVE-2019-13648. Fixes: 2b0a576d15e0 ("powerpc: Add new transactional memory state to the signal context") Cc: stable@vger.kernel.org # v3.9 Reported-by: Praveen Pandey <Praveen.Pandey@in.ibm.com> Signed-off-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20190719050502.405-1-mikey@neuling.org
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#
2874c5fd |
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27-May-2019 |
Thomas Gleixner <tglx@linutronix.de> |
treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license as published by the free software foundation either version 2 of the license or at your option any later version extracted by the scancode license scanner the SPDX license identifier GPL-2.0-or-later has been chosen to replace the boilerplate/reference in 3029 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Allison Randal <allison@lohutok.net> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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3cf5d076 |
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23-May-2019 |
Eric W. Biederman <ebiederm@xmission.com> |
signal: Remove task parameter from force_sig All of the remaining callers pass current into force_sig so remove the task parameter to make this obvious and to make misuse more difficult in the future. This also makes it clear force_sig passes current into force_sig_info. Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
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e620d450 |
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16-Jan-2019 |
Breno Leitao <leitao@debian.org> |
powerpc/tm: Avoid machine crash on rt_sigreturn() There is a kernel crash that happens if rt_sigreturn() is called inside a transactional block. This crash happens if the kernel hits an in-kernel page fault when accessing userspace memory, usually through copy_ckvsx_to_user(). A major page fault calls might_sleep() function, which can cause a task reschedule. A task reschedule (switch_to()) reclaim and recheckpoint the TM states, but, in the signal return path, the checkpointed memory was already reclaimed, thus the exception stack has MSR that points to MSR[TS]=0. When the code returns from might_sleep() and a task reschedule happened, then this task is returned with the memory recheckpointed, and CPU MSR[TS] = suspended. This means that there is a side effect at might_sleep() if it is called with CPU MSR[TS] = 0 and the task has regs->msr[TS] != 0. This side effect can cause a TM bad thing, since at the exception entrance, the stack saves MSR[TS]=0, and this is what will be used at RFID, but, the processor has MSR[TS] = Suspended, and this transition will be invalid and a TM Bad thing will be raised, causing the following crash: Unexpected TM Bad Thing exception at c00000000000e9ec (msr 0x8000000302a03031) tm_scratch=800000010280b033 cpu 0xc: Vector: 700 (Program Check) at [c00000003ff1fd70] pc: c00000000000e9ec: fast_exception_return+0x100/0x1bc lr: c000000000032948: handle_rt_signal64+0xb8/0xaf0 sp: c0000004263ebc40 msr: 8000000302a03031 current = 0xc000000415050300 paca = 0xc00000003ffc4080 irqmask: 0x03 irq_happened: 0x01 pid = 25006, comm = sigfuz Linux version 5.0.0-rc1-00001-g3bd6e94bec12 (breno@debian) (gcc version 8.2.0 (Debian 8.2.0-3)) #899 SMP Mon Jan 7 11:30:07 EST 2019 WARNING: exception is not recoverable, can't continue enter ? for help [c0000004263ebc40] c000000000032948 handle_rt_signal64+0xb8/0xaf0 (unreliable) [c0000004263ebd30] c000000000022780 do_notify_resume+0x2f0/0x430 [c0000004263ebe20] c00000000000e844 ret_from_except_lite+0x70/0x74 --- Exception: c00 (System Call) at 00007fffbaac400c SP (7fffeca90f40) is in userspace The solution for this problem is running the sigreturn code with regs->msr[TS] disabled, thus, avoiding hitting the side effect above. This does not seem to be a problem since regs->msr will be replaced by the ucontext value, so, it is being flushed already. In this case, it is flushed earlier. Signed-off-by: Breno Leitao <leitao@debian.org> Acked-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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#
897bc3df |
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09-Jan-2019 |
Breno Leitao <leitao@debian.org> |
powerpc/tm: Limit TM code inside PPC_TRANSACTIONAL_MEM Commit e1c3743e1a20 ("powerpc/tm: Set MSR[TS] just prior to recheckpoint") moved a code block around and this block uses a 'msr' variable outside of the CONFIG_PPC_TRANSACTIONAL_MEM, however the 'msr' variable is declared inside a CONFIG_PPC_TRANSACTIONAL_MEM block, causing a possible error when CONFIG_PPC_TRANSACTION_MEM is not defined. error: 'msr' undeclared (first use in this function) This is not causing a compilation error in the mainline kernel, because 'msr' is being used as an argument of MSR_TM_ACTIVE(), which is defined as the following when CONFIG_PPC_TRANSACTIONAL_MEM is *not* set: #define MSR_TM_ACTIVE(x) 0 This patch just fixes this issue avoiding the 'msr' variable usage outside the CONFIG_PPC_TRANSACTIONAL_MEM block, avoiding trusting in the MSR_TM_ACTIVE() definition. Cc: stable@vger.kernel.org Reported-by: Christoph Biedl <linux-kernel.bfrz@manchmal.in-ulm.de> Fixes: e1c3743e1a20 ("powerpc/tm: Set MSR[TS] just prior to recheckpoint") Signed-off-by: Breno Leitao <leitao@debian.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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96d4f267 |
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03-Jan-2019 |
Linus Torvalds <torvalds@linux-foundation.org> |
Remove 'type' argument from access_ok() function Nobody has actually used the type (VERIFY_READ vs VERIFY_WRITE) argument of the user address range verification function since we got rid of the old racy i386-only code to walk page tables by hand. It existed because the original 80386 would not honor the write protect bit when in kernel mode, so you had to do COW by hand before doing any user access. But we haven't supported that in a long time, and these days the 'type' argument is a purely historical artifact. A discussion about extending 'user_access_begin()' to do the range checking resulted this patch, because there is no way we're going to move the old VERIFY_xyz interface to that model. And it's best done at the end of the merge window when I've done most of my merges, so let's just get this done once and for all. This patch was mostly done with a sed-script, with manual fix-ups for the cases that weren't of the trivial 'access_ok(VERIFY_xyz' form. There were a couple of notable cases: - csky still had the old "verify_area()" name as an alias. - the iter_iov code had magical hardcoded knowledge of the actual values of VERIFY_{READ,WRITE} (not that they mattered, since nothing really used it) - microblaze used the type argument for a debug printout but other than those oddities this should be a total no-op patch. I tried to fix up all architectures, did fairly extensive grepping for access_ok() uses, and the changes are trivial, but I may have missed something. Any missed conversion should be trivially fixable, though. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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6f5b9f01 |
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26-Nov-2018 |
Breno Leitao <leitao@debian.org> |
powerpc/tm: Unset MSR[TS] if not recheckpointing There is a TM Bad Thing bug that can be caused when you return from a signal context in a suspended transaction but with ucontext MSR[TS] unset. This forces regs->msr[TS] to be set at syscall entrance (since the CPU state is transactional). It also calls treclaim() to flush the transaction state, which is done based on the live (mfmsr) MSR state. Since user context MSR[TS] is not set, then restore_tm_sigcontexts() is not called, thus, not executing recheckpoint, keeping the CPU state as not transactional. When calling rfid, SRR1 will have MSR[TS] set, but the CPU state is non transactional, causing the TM Bad Thing with the following stack: [ 33.862316] Bad kernel stack pointer 3fffd9dce3e0 at c00000000000c47c cpu 0x8: Vector: 700 (Program Check) at [c00000003ff7fd40] pc: c00000000000c47c: fast_exception_return+0xac/0xb4 lr: 00003fff865f442c sp: 3fffd9dce3e0 msr: 8000000102a03031 current = 0xc00000041f68b700 paca = 0xc00000000fb84800 softe: 0 irq_happened: 0x01 pid = 1721, comm = tm-signal-sigre Linux version 4.9.0-3-powerpc64le (debian-kernel@lists.debian.org) (gcc version 6.3.0 20170516 (Debian 6.3.0-18) ) #1 SMP Debian 4.9.30-2+deb9u2 (2017-06-26) WARNING: exception is not recoverable, can't continue The same problem happens on 32-bits signal handler, and the fix is very similar, if tm_recheckpoint() is not executed, then regs->msr[TS] should be zeroed. This patch also fixes a sparse warning related to lack of indentation when CONFIG_PPC_TRANSACTIONAL_MEM is set. Fixes: 2b0a576d15e0e ("powerpc: Add new transactional memory state to the signal context") CC: Stable <stable@vger.kernel.org> # 3.10+ Signed-off-by: Breno Leitao <leitao@debian.org> Tested-by: Michal Suchánek <msuchanek@suse.de> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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#
e1c3743e |
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21-Nov-2018 |
Breno Leitao <leitao@debian.org> |
powerpc/tm: Set MSR[TS] just prior to recheckpoint On a signal handler return, the user could set a context with MSR[TS] bits set, and these bits would be copied to task regs->msr. At restore_tm_sigcontexts(), after current task regs->msr[TS] bits are set, several __get_user() are called and then a recheckpoint is executed. This is a problem since a page fault (in kernel space) could happen when calling __get_user(). If it happens, the process MSR[TS] bits were already set, but recheckpoint was not executed, and SPRs are still invalid. The page fault can cause the current process to be de-scheduled, with MSR[TS] active and without tm_recheckpoint() being called. More importantly, without TEXASR[FS] bit set also. Since TEXASR might not have the FS bit set, and when the process is scheduled back, it will try to reclaim, which will be aborted because of the CPU is not in the suspended state, and, then, recheckpoint. This recheckpoint will restore thread->texasr into TEXASR SPR, which might be zero, hitting a BUG_ON(). kernel BUG at /build/linux-sf3Co9/linux-4.9.30/arch/powerpc/kernel/tm.S:434! cpu 0xb: Vector: 700 (Program Check) at [c00000041f1576d0] pc: c000000000054550: restore_gprs+0xb0/0x180 lr: 0000000000000000 sp: c00000041f157950 msr: 8000000100021033 current = 0xc00000041f143000 paca = 0xc00000000fb86300 softe: 0 irq_happened: 0x01 pid = 1021, comm = kworker/11:1 kernel BUG at /build/linux-sf3Co9/linux-4.9.30/arch/powerpc/kernel/tm.S:434! Linux version 4.9.0-3-powerpc64le (debian-kernel@lists.debian.org) (gcc version 6.3.0 20170516 (Debian 6.3.0-18) ) #1 SMP Debian 4.9.30-2+deb9u2 (2017-06-26) enter ? for help [c00000041f157b30] c00000000001bc3c tm_recheckpoint.part.11+0x6c/0xa0 [c00000041f157b70] c00000000001d184 __switch_to+0x1e4/0x4c0 [c00000041f157bd0] c00000000082eeb8 __schedule+0x2f8/0x990 [c00000041f157cb0] c00000000082f598 schedule+0x48/0xc0 [c00000041f157ce0] c0000000000f0d28 worker_thread+0x148/0x610 [c00000041f157d80] c0000000000f96b0 kthread+0x120/0x140 [c00000041f157e30] c00000000000c0e0 ret_from_kernel_thread+0x5c/0x7c This patch simply delays the MSR[TS] set, so, if there is any page fault in the __get_user() section, it does not have regs->msr[TS] set, since the TM structures are still invalid, thus avoiding doing TM operations for in-kernel exceptions and possible process reschedule. With this patch, the MSR[TS] will only be set just before recheckpointing and setting TEXASR[FS] = 1, thus avoiding an interrupt with TM registers in invalid state. Other than that, if CONFIG_PREEMPT is set, there might be a preemption just after setting MSR[TS] and before tm_recheckpoint(), thus, this block must be atomic from a preemption perspective, thus, calling preempt_disable/enable() on this code. It is not possible to move tm_recheckpoint to happen earlier, because it is required to get the checkpointed registers from userspace, with __get_user(), thus, the only way to avoid this undesired behavior is delaying the MSR[TS] set. The 32-bits signal handler seems to be safe this current issue, but, it might be exposed to the preemption issue, thus, disabling preemption in this chunk of code. Changes from v2: * Run the critical section with preempt_disable. Fixes: 87b4e5393af7 ("powerpc/tm: Fix return of active 64bit signals") Cc: stable@vger.kernel.org (v3.9+) Signed-off-by: Breno Leitao <leitao@debian.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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d16952a6 |
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09-Nov-2018 |
Christophe Leroy <christophe.leroy@c-s.fr> |
powerpc/signal: Use code patching instead of hardcoding Instead of hardcoding code modifications, use code patching functions. Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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ac851744 |
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19-Jun-2018 |
Paul Burton <paulburton@kernel.org> |
powerpc: Remove -Wattribute-alias pragmas With SYSCALL_DEFINEx() disabling -Wattribute-alias generically, there's no need to duplicate that for PowerPC syscalls. This reverts commit 415520373975 ("powerpc: fix build failure by disabling attribute-alias warning in pci_32") and commit 2479bfc9bc60 ("powerpc: Fix build by disabling attribute-alias warning for SYSCALL_DEFINEx"). Signed-off-by: Paul Burton <paul.burton@mips.com> Acked-by: Christophe Leroy <christophe.leroy@c-s.fr> Acked-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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2479bfc9 |
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29-May-2018 |
Christophe Leroy <christophe.leroy@c-s.fr> |
powerpc: Fix build by disabling attribute-alias warning for SYSCALL_DEFINEx GCC 8.1 emits warnings such as the following. As arch/powerpc code is built with -Werror, this breaks the build with GCC 8.1. In file included from arch/powerpc/kernel/pci_64.c:23: ./include/linux/syscalls.h:233:18: error: 'sys_pciconfig_iobase' alias between functions of incompatible types 'long int(long int, long unsigned int, long unsigned int)' and 'long int(long int, long int, long int)' [-Werror=attribute-alias] asmlinkage long sys##name(__MAP(x,__SC_DECL,__VA_ARGS__)) \ ^~~ ./include/linux/syscalls.h:222:2: note: in expansion of macro '__SYSCALL_DEFINEx' __SYSCALL_DEFINEx(x, sname, __VA_ARGS__) This patch inhibits those warnings. Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> [mpe: Trim change log] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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f3675644 |
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02-May-2018 |
Al Viro <viro@zeniv.linux.org.uk> |
powerpc/syscalls: signal_{32, 64} - switch to SYSCALL_DEFINE Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> [mpe: Fix sys_debug_setcontext() prototype to return long] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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1c200e63 |
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31-Dec-2017 |
Gustavo Romero <gromero@linux.vnet.ibm.com> |
powerpc/tm: Fix endianness flip on trap Currently it's possible that a thread on PPC64 LE has its endianness flipped inadvertently to Big-Endian resulting in a crash once the process is back from the signal handler. If giveup_all() is called when regs->msr has the bits MSR.FP and MSR.VEC disabled (and hence MSR.VSX disabled too) it returns without calling check_if_tm_restore_required() which copies regs->msr to ckpt_regs->msr if the process caught a signal whilst in transactional mode. Then once in setup_tm_sigcontexts() MSR from ckpt_regs.msr is used, but since check_if_tm_restore_required() was not called previuosly, gp_regs[PT_MSR] gets a copy of invalid MSR bits as MSR in ckpt_regs was not updated from regs->msr and so is zeroed. Later when leaving the signal handler once in sys_rt_sigreturn() the TS bits of gp_regs[PT_MSR] are checked to determine if restore_tm_sigcontexts() must be called to pull in the correct MSR state into the user context. Because TS bits are zeroed restore_tm_sigcontexts() is never called and MSR restored from the user context on returning from the signal handler has the MSR.LE (the endianness bit) forced to zero (Big-Endian). That leads, for instance, to 'nop' being treated as an illegal instruction in the following sequence: tbegin. beq 1f trap tend. 1: nop on PPC64 LE machines and the process dies just after returning from the signal handler. PPC64 BE is also affected but in a subtle way since forcing Big-Endian on a BE machine does not change the endianness. This commit fixes the issue described above by ensuring that once in setup_tm_sigcontexts() the MSR used is from regs->msr instead of from ckpt_regs->msr and by ensuring that we pull in only the MSR.FP, MSR.VEC, and MSR.VSX bits from ckpt_regs->msr. The fix was tested both on LE and BE machines and no regression regarding the powerpc/tm selftests was observed. Signed-off-by: Gustavo Romero <gromero@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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a8a4b03a |
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20-Aug-2017 |
Madhavan Srinivasan <maddy@linux.vnet.ibm.com> |
powerpc: Hard wire PT_SOFTE value to 1 in ptrace & signals We have always had softe in pt_regs, and accessible via PT_SOFTE, even though it is not userspace state. The value userspace sees should always be 1, because we should never be in userspace with interrupts soft disabled. In a subsequent patch we will be changing the semantics of the kernel softe value, so hard wire the value to 1 to retain the existing semantics. As far as we know nothing ever looks at it, but better safe than sorry. Signed-off-by: Madhavan Srinivasan <maddy@linux.vnet.ibm.com> [mpe: Split out of larger patch, write change log] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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eb5c3f1c |
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01-Nov-2017 |
Cyril Bur <cyrilbur@gmail.com> |
powerpc: Always save/restore checkpointed regs during treclaim/trecheckpoint Lazy save and restore of FP/Altivec means that a userspace process can be sent to userspace with FP or Altivec disabled and loaded only as required (by way of an FP/Altivec unavailable exception). Transactional Memory complicates this situation as a transaction could be started without FP/Altivec being loaded up. This causes the hardware to checkpoint incorrect registers. Handling FP/Altivec unavailable exceptions while a thread is transactional requires a reclaim and recheckpoint to ensure the CPU has correct state for both sets of registers. tm_reclaim() has optimisations to not always save the FP/Altivec registers to the checkpointed save area. This was originally done because the caller might have information that the checkpointed registers aren't valid due to lazy save and restore. We've also been a little vague as to how tm_reclaim() leaves the FP/Altivec state since it doesn't necessarily always save it to the thread struct. This has lead to an (incorrect) assumption that it leaves the checkpointed state on the CPU. tm_recheckpoint() has similar optimisations in reverse. It may not always reload the checkpointed FP/Altivec registers from the thread struct before the trecheckpoint. It is therefore quite unclear where it expects to get the state from. This didn't help with the assumption made about tm_reclaim(). These optimisations sit in what is by definition a slow path. If a process has to go through a reclaim/recheckpoint then its transaction will be doomed on returning to userspace. This mean that the process will be unable to complete its transaction and be forced to its failure handler. This is already an out if line case for userspace. Furthermore, the cost of copying 64 times 128 bits from registers isn't very long[0] (at all) on modern processors. As such it appears these optimisations have only served to increase code complexity and are unlikely to have had a measurable performance impact. Our transactional memory handling has been riddled with bugs. A cause of this has been difficulty in following the code flow, code complexity has not been our friend here. It makes sense to remove these optimisations in favour of a (hopefully) more stable implementation. This patch does mean that some times the assembly will needlessly save 'junk' registers which will subsequently get overwritten with the correct value by the C code which calls the assembly function. This small inefficiency is far outweighed by the reduction in complexity for general TM code, context switching paths, and transactional facility unavailable exception handler. 0: I tried to measure it once for other work and found that it was hiding in the noise of everything else I was working with. I find it exceedingly likely this will be the case here. Signed-off-by: Cyril Bur <cyrilbur@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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92fb8690 |
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12-Oct-2017 |
Michael Neuling <mikey@neuling.org> |
powerpc/tm: P9 disable transactionally suspended sigcontexts Unfortunately userspace can construct a sigcontext which enables suspend. Thus userspace can force Linux into a path where trechkpt is executed. This patch blocks this from happening on POWER9 by sanity checking sigcontexts passed in. ptrace doesn't have this problem as only MSR SE and BE can be changed via ptrace. This patch also adds a number of WARN_ON()s in case we ever enter suspend when we shouldn't. This should not happen, but if it does the symptoms are soft lockup warnings which are not obviously TM related, so the WARN_ON()s should make it obvious what's happening. Signed-off-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Cyril Bur <cyrilbur@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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044215d1 |
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22-Aug-2017 |
Gustavo Romero <gromero@linux.vnet.ibm.com> |
powerpc/tm: Fix illegal TM state in signal handler Currently it's possible that on returning from the signal handler through the restore_tm_sigcontexts() code path (e.g. from a signal caught due to a `trap` instruction executed in the middle of an HTM block, or a deliberately constructed sigframe) an illegal TM state (like TS=10 TM=0, i.e. "T0") is set in SRR1 and when `rfid` sets implicitly the MSR register from SRR1 register on return to userspace it causes a TM Bad Thing exception. That illegal state can be set (a) by a malicious user that disables the TM bit by tweaking the bits in uc_mcontext before returning from the signal handler or (b) by a sufficient number of context switches occurring such that the load_tm counter overflows and TM is disabled whilst in the signal handler. This commit fixes the illegal TM state by ensuring that TM bit is always enabled before we return from restore_tm_sigcontexts(). A small comment correction is made as well. Fixes: 5d176f751ee3 ("powerpc: tm: Enable transactional memory (TM) lazily for userspace") Cc: stable@vger.kernel.org # v4.9+ Signed-off-by: Gustavo Romero <gromero@linux.vnet.ibm.com> Signed-off-by: Breno Leitao <leitao@debian.org> Signed-off-by: Cyril Bur <cyrilbur@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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7c0f6ba6 |
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24-Dec-2016 |
Linus Torvalds <torvalds@linux-foundation.org> |
Replace <asm/uaccess.h> with <linux/uaccess.h> globally This was entirely automated, using the script by Al: PATT='^[[:blank:]]*#[[:blank:]]*include[[:blank:]]*<asm/uaccess.h>' sed -i -e "s!$PATT!#include <linux/uaccess.h>!" \ $(git grep -l "$PATT"|grep -v ^include/linux/uaccess.h) to do the replacement at the end of the merge window. Requested-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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000ec280 |
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23-Sep-2016 |
Cyril Bur <cyrilbur@gmail.com> |
powerpc: tm: Rename transct_(*) to ck(\1)_state Make the structures being used for checkpointed state named consistently with the pt_regs/ckpt_regs. Signed-off-by: Cyril Bur <cyrilbur@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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dc310669 |
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23-Sep-2016 |
Cyril Bur <cyrilbur@gmail.com> |
powerpc: tm: Always use fp_state and vr_state to store live registers There is currently an inconsistency as to how the entire CPU register state is saved and restored when a thread uses transactional memory (TM). Using transactional memory results in the CPU having duplicated (almost) all of its register state. This duplication results in a set of registers which can be considered 'live', those being currently modified by the instructions being executed and another set that is frozen at a point in time. On context switch, both sets of state have to be saved and (later) restored. These two states are often called a variety of different things. Common terms for the state which only exists after the CPU has entered a transaction (performed a TBEGIN instruction) in hardware are 'transactional' or 'speculative'. Between a TBEGIN and a TEND or TABORT (or an event that causes the hardware to abort), regardless of the use of TSUSPEND the transactional state can be referred to as the live state. The second state is often to referred to as the 'checkpointed' state and is a duplication of the live state when the TBEGIN instruction is executed. This state is kept in the hardware and will be rolled back to on transaction failure. Currently all the registers stored in pt_regs are ALWAYS the live registers, that is, when a thread has transactional registers their values are stored in pt_regs and the checkpointed state is in ckpt_regs. A strange opposite is true for fp_state/vr_state. When a thread is non transactional fp_state/vr_state holds the live registers. When a thread has initiated a transaction fp_state/vr_state holds the checkpointed state and transact_fp/transact_vr become the structure which holds the live state (at this point it is a transactional state). This method creates confusion as to where the live state is, in some circumstances it requires extra work to determine where to put the live state and prevents the use of common functions designed (probably before TM) to save the live state. With this patch pt_regs, fp_state and vr_state all represent the same thing and the other structures [pending rename] are for checkpointed state. Acked-by: Simon Guo <wei.guo.simon@gmail.com> Signed-off-by: Cyril Bur <cyrilbur@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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d1199431 |
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23-Sep-2016 |
Cyril Bur <cyrilbur@gmail.com> |
powerpc: signals: Stop using current in signal code Much of the signal code takes a pt_regs on which it operates. Over time the signal code has needed to know more about the thread than what pt_regs can supply, this information is obtained as needed by using 'current'. This approach is not strictly incorrect however it does mean that there is now a hard requirement that the pt_regs being passed around does belong to current, this is never checked. A safer approach is for the majority of the signal functions to take a task_struct from which they can obtain pt_regs and any other information they need. The caveat that the task_struct they are passed must be current doesn't go away but can more easily be checked for. Functions called from outside powerpc signal code are passed a pt_regs and they can confirm that the pt_regs is that of current and pass current to other functions, furthurmore, powerpc signal functions can check that the task_struct they are passed is the same as current avoiding possible corruption of current (or the task they are passed) if this assertion ever fails. CC: paulus@samba.org Signed-off-by: Cyril Bur <cyrilbur@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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e1c0d66f |
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26-Jul-2016 |
Simon Guo <wei.guo.simon@gmail.com> |
powerpc: Set used_(vsr|vr|spe) in sigreturn path when MSR bits are active Normally, when MSR[VSX/VR/SPE] bits == 1, the used_vsr/used_vr/used_spe bit have already been set. However when loading a signal frame from user space we need to explicitly set used_vsr/used_vr/used_spe to make them consistent with the MSR bits from the signal frame. For example, CRIU application, who utilizes sigreturn to restore checkpointed process, will lead to the case where MSR[VSX] bit is active in signal frame, but used_vsr bit is not set in the kernel. (the same applies to VR/SPE). This patch fixes this by always setting used_* bit when MSR related bits are active in signal frame and we are doing sigreturn. Based on a proposal by Benh. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Simon Guo <wei.guo.simon@gmail.com> [mpe: Massage change log] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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0545d543 |
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05-Sep-2016 |
Daniel Axtens <dja@axtens.net> |
powerpc/sparse: Add more assembler prototypes Another set of things that are only called from assembler and so need prototypes to keep sparse happy. Signed-off-by: Daniel Axtens <dja@axtens.net> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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78a3e888 |
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22-Aug-2016 |
Cyril Bur <cyrilbur@gmail.com> |
powerpc: signals: Discard transaction state from signal frames Userspace can begin and suspend a transaction within the signal handler which means they might enter sys_rt_sigreturn() with the processor in suspended state. sys_rt_sigreturn() wants to restore process context (which may have been in a transaction before signal delivery). To do this it must restore TM SPRS. To achieve this, any transaction initiated within the signal frame must be discarded in order to be able to restore TM SPRs as TM SPRs can only be manipulated non-transactionally.. >From the PowerPC ISA: TM Bad Thing Exception [Category: Transactional Memory] An attempt is made to execute a mtspr targeting a TM register in other than Non-transactional state. Not doing so results in a TM Bad Thing: [12045.221359] Kernel BUG at c000000000050a40 [verbose debug info unavailable] [12045.221470] Unexpected TM Bad Thing exception at c000000000050a40 (msr 0x201033) [12045.221540] Oops: Unrecoverable exception, sig: 6 [#1] [12045.221586] SMP NR_CPUS=2048 NUMA PowerNV [12045.221634] Modules linked in: xt_CHECKSUM iptable_mangle ipt_MASQUERADE nf_nat_masquerade_ipv4 iptable_nat nf_nat_ipv4 nf_nat nf_conntrack_ipv4 nf_defrag_ipv4 xt_conntrack nf_conntrack ipt_REJECT nf_reject_ipv4 xt_tcpudp bridge stp llc ebtable_filter ebtables ip6table_filter ip6_tables iptable_filter ip_tables x_tables kvm_hv kvm uio_pdrv_genirq ipmi_powernv uio powernv_rng ipmi_msghandler autofs4 ses enclosure scsi_transport_sas bnx2x ipr mdio libcrc32c [12045.222167] CPU: 68 PID: 6178 Comm: sigreturnpanic Not tainted 4.7.0 #34 [12045.222224] task: c0000000fce38600 ti: c0000000fceb4000 task.ti: c0000000fceb4000 [12045.222293] NIP: c000000000050a40 LR: c0000000000163bc CTR: 0000000000000000 [12045.222361] REGS: c0000000fceb7ac0 TRAP: 0700 Not tainted (4.7.0) [12045.222418] MSR: 9000000300201033 <SF,HV,ME,IR,DR,RI,LE,TM[SE]> CR: 28444280 XER: 20000000 [12045.222625] CFAR: c0000000000163b8 SOFTE: 0 PACATMSCRATCH: 900000014280f033 GPR00: 01100000b8000001 c0000000fceb7d40 c00000000139c100 c0000000fce390d0 GPR04: 900000034280f033 0000000000000000 0000000000000000 0000000000000000 GPR08: 0000000000000000 b000000000001033 0000000000000001 0000000000000000 GPR12: 0000000000000000 c000000002926400 0000000000000000 0000000000000000 GPR16: 0000000000000000 0000000000000000 0000000000000000 0000000000000000 GPR20: 0000000000000000 0000000000000000 0000000000000000 0000000000000000 GPR24: 0000000000000000 00003ffff98cadd0 00003ffff98cb470 0000000000000000 GPR28: 900000034280f033 c0000000fceb7ea0 0000000000000001 c0000000fce390d0 [12045.223535] NIP [c000000000050a40] tm_restore_sprs+0xc/0x1c [12045.223584] LR [c0000000000163bc] tm_recheckpoint+0x5c/0xa0 [12045.223630] Call Trace: [12045.223655] [c0000000fceb7d80] [c000000000026e74] sys_rt_sigreturn+0x494/0x6c0 [12045.223738] [c0000000fceb7e30] [c0000000000092e0] system_call+0x38/0x108 [12045.223806] Instruction dump: [12045.223841] 7c800164 4e800020 7c0022a6 f80304a8 7c0222a6 f80304b0 7c0122a6 f80304b8 [12045.223955] 4e800020 e80304a8 7c0023a6 e80304b0 <7c0223a6> e80304b8 7c0123a6 4e800020 [12045.224074] ---[ end trace cb8002ee240bae76 ]--- It isn't clear exactly if there is really a use case for userspace returning with a suspended transaction, however, doing so doesn't (on its own) constitute a bad frame. As such, this patch simply discards the transactional state of the context calling the sigreturn and continues. Reported-by: Laurent Dufour <ldufour@linux.vnet.ibm.com> Signed-off-by: Cyril Bur <cyrilbur@gmail.com> Tested-by: Laurent Dufour <ldufour@linux.vnet.ibm.com> Reviewed-by: Laurent Dufour <ldufour@linux.vnet.ibm.com> Acked-by: Simon Guo <wei.guo.simon@gmail.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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d96f234f |
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29-May-2016 |
Anton Blanchard <anton@samba.org> |
powerpc: Avoid load hit store in setup_sigcontext() In setup_sigcontext(), we set current->thread.vrsave then use it straight after. Since current is hidden from the compiler via inline assembly, it cannot optimise this and we end up with a load hit store. Fix this by using a temporary. Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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a7d623d4 |
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28-Oct-2015 |
Anton Blanchard <anton@samba.org> |
powerpc: Move part of giveup_vsx into c Move the MSR modification into c. Removing it from the assembly function will allow us to avoid costly MSR writes by batching them up. Check the FP and VMX bits before calling the relevant giveup_*() function. This makes giveup_vsx() and flush_vsx_to_thread() perform more like their sister functions, and allows us to use flush_vsx_to_thread() in the signal code. Move the check_if_tm_restore_required() check in. Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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af1bbc3d |
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28-Oct-2015 |
Anton Blanchard <anton@samba.org> |
powerpc: Remove UP only lazy floating point and vector optimisations The UP only lazy floating point and vector optimisations were written back when SMP was not common, and neither glibc nor gcc used vector instructions. Now SMP is very common, glibc aggressively uses vector instructions and gcc autovectorises. We want to add new optimisations that apply to both UP and SMP, but in preparation for that remove these UP only optimisations. Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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d2b9d2a5 |
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18-Nov-2015 |
Michael Neuling <mikey@neuling.org> |
powerpc/tm: Block signal return setting invalid MSR state Currently we allow both the MSR T and S bits to be set by userspace on a signal return. Unfortunately this is a reserved configuration and will cause a TM Bad Thing exception if attempted (via rfid). This patch checks for this case in both the 32 and 64 bit signals code. If both T and S are set, we mark the context as invalid. Found using a syscall fuzzer. Fixes: 2b0a576d15e0 ("powerpc: Add new transactional memory state to the signal context") Cc: stable@vger.kernel.org # v3.9+ Signed-off-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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2476c09f |
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19-Jul-2015 |
Anshuman Khandual <khandual@linux.vnet.ibm.com> |
powerpc/signal: Add helper function to fetch quad word aligned pointer This patch adds one helper function 'sigcontext_vmx_regs' which computes quad word aligned pointer for 'vmx_reserve' array element in sigcontext structure making the code more readable. Signed-off-by: Anshuman Khandual <khandual@linux.vnet.ibm.com> [mpe: Reword comment and fix build for CONFIG_ALTIVEC=n] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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f56141e3 |
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12-Feb-2015 |
Andy Lutomirski <luto@amacapital.net> |
all arches, signal: move restart_block to struct task_struct If an attacker can cause a controlled kernel stack overflow, overwriting the restart block is a very juicy exploit target. This is because the restart_block is held in the same memory allocation as the kernel stack. Moving the restart block to struct task_struct prevents this exploit by making the restart_block harder to locate. Note that there are other fields in thread_info that are also easy targets, at least on some architectures. It's also a decent simplification, since the restart code is more or less identical on all architectures. [james.hogan@imgtec.com: metag: align thread_info::supervisor_stack] Signed-off-by: Andy Lutomirski <luto@amacapital.net> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Kees Cook <keescook@chromium.org> Cc: David Miller <davem@davemloft.net> Acked-by: Richard Weinberger <richard@nod.at> Cc: Richard Henderson <rth@twiddle.net> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Cc: Matt Turner <mattst88@gmail.com> Cc: Vineet Gupta <vgupta@synopsys.com> Cc: Russell King <rmk@arm.linux.org.uk> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Haavard Skinnemoen <hskinnemoen@gmail.com> Cc: Hans-Christian Egtvedt <egtvedt@samfundet.no> Cc: Steven Miao <realmz6@gmail.com> Cc: Mark Salter <msalter@redhat.com> Cc: Aurelien Jacquiot <a-jacquiot@ti.com> Cc: Mikael Starvik <starvik@axis.com> Cc: Jesper Nilsson <jesper.nilsson@axis.com> Cc: David Howells <dhowells@redhat.com> Cc: Richard Kuo <rkuo@codeaurora.org> Cc: "Luck, Tony" <tony.luck@intel.com> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Michal Simek <monstr@monstr.eu> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Jonas Bonn <jonas@southpole.se> Cc: "James E.J. Bottomley" <jejb@parisc-linux.org> Cc: Helge Deller <deller@gmx.de> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc) Tested-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc) Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Chen Liqin <liqin.linux@gmail.com> Cc: Lennox Wu <lennox.wu@gmail.com> Cc: Chris Metcalf <cmetcalf@ezchip.com> Cc: Guan Xuetao <gxt@mprc.pku.edu.cn> Cc: Chris Zankel <chris@zankel.net> Cc: Max Filippov <jcmvbkbc@gmail.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Guenter Roeck <linux@roeck-us.net> Signed-off-by: James Hogan <james.hogan@imgtec.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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#
059ade65 |
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05-Mar-2014 |
Richard Weinberger <richard@nod.at> |
powerpc: Use sigsp() Use sigsp() instead of the open coded variant. Signed-off-by: Richard Weinberger <richard@nod.at>
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#
129b69df |
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02-Mar-2014 |
Richard Weinberger <richard@nod.at> |
powerpc: Use get_signal() signal_setup_done() Use the more generic functions get_signal() signal_setup_done() for signal delivery. This inverts also the return codes of setup_*frame() to follow the kernel convention. Signed-off-by: Richard Weinberger <richard@nod.at>
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#
bf77ee2a |
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22-Jun-2014 |
Michael Ellerman <mpe@ellerman.id.au> |
powerpc: Remove ancient DEBUG_SIG code We have some compile-time disabled debug code in signal_xx.c. It's from some ancient time BG, almost certainly part of the original port, given the very similar code on other arches. The show_unhandled_signal logic, added in d0c3d534a438 (2.6.24) is cleaner and prints more useful information, so drop the debug code. Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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#
e6b8fd02 |
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04-Apr-2014 |
Michael Neuling <mikey@neuling.org> |
powerpc/tm: Disable IRQ in tm_recheckpoint We can't take an IRQ when we're about to do a trechkpt as our GPR state is set to user GPR values. We've hit this when running some IBM Java stress tests in the lab resulting in the following dump: cpu 0x3f: Vector: 700 (Program Check) at [c000000007eb3d40] pc: c000000000050074: restore_gprs+0xc0/0x148 lr: 00000000b52a8184 sp: ac57d360 msr: 8000000100201030 current = 0xc00000002c500000 paca = 0xc000000007dbfc00 softe: 0 irq_happened: 0x00 pid = 34535, comm = Pooled Thread # R00 = 00000000b52a8184 R16 = 00000000b3e48fda R01 = 00000000ac57d360 R17 = 00000000ade79bd8 R02 = 00000000ac586930 R18 = 000000000fac9bcc R03 = 00000000ade60000 R19 = 00000000ac57f930 R04 = 00000000f6624918 R20 = 00000000ade79be8 R05 = 00000000f663f238 R21 = 00000000ac218a54 R06 = 0000000000000002 R22 = 000000000f956280 R07 = 0000000000000008 R23 = 000000000000007e R08 = 000000000000000a R24 = 000000000000000c R09 = 00000000b6e69160 R25 = 00000000b424cf00 R10 = 0000000000000181 R26 = 00000000f66256d4 R11 = 000000000f365ec0 R27 = 00000000b6fdcdd0 R12 = 00000000f66400f0 R28 = 0000000000000001 R13 = 00000000ada71900 R29 = 00000000ade5a300 R14 = 00000000ac2185a8 R30 = 00000000f663f238 R15 = 0000000000000004 R31 = 00000000f6624918 pc = c000000000050074 restore_gprs+0xc0/0x148 cfar= c00000000004fe28 dont_restore_vec+0x1c/0x1a4 lr = 00000000b52a8184 msr = 8000000100201030 cr = 24804888 ctr = 0000000000000000 xer = 0000000000000000 trap = 700 This moves tm_recheckpoint to a C function and moves the tm_restore_sprs into that function. It then adds IRQ disabling over the trechkpt critical section. It also sets the TEXASR FS in the signals code to ensure this is never set now that we explictly write the TM sprs in tm_recheckpoint. Signed-off-by: Michael Neuling <mikey@neuling.org> cc: stable@vger.kernel.org Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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#
573ebfa6 |
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25-Feb-2014 |
Paul Mackerras <paulus@samba.org> |
powerpc: Increase stack redzone for 64-bit userspace to 512 bytes The new ELFv2 little-endian ABI increases the stack redzone -- the area below the stack pointer that can be used for storing data -- from 288 bytes to 512 bytes. This means that we need to allow more space on the user stack when delivering a signal to a 64-bit process. To make the code a bit clearer, we define new USER_REDZONE_SIZE and KERNEL_REDZONE_SIZE symbols in ptrace.h. For now, we leave the kernel redzone size at 288 bytes, since increasing it to 512 bytes would increase the size of interrupt stack frames correspondingly. Gcc currently only makes use of 288 bytes of redzone even when compiling for the new little-endian ABI, and the kernel cannot currently be compiled with the new ABI anyway. In the future, hopefully gcc will provide an option to control the amount of redzone used, and then we could reduce it even more. This also changes the code in arch_compat_alloc_user_space() to preserve the expanded redzone. It is not clear why this function would ever be used on a 64-bit process, though. Signed-off-by: Paul Mackerras <paulus@samba.org> CC: <stable@vger.kernel.org> [v3.13] Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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#
d31626f7 |
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12-Jan-2014 |
Paul Mackerras <paulus@samba.org> |
powerpc: Don't corrupt transactional state when using FP/VMX in kernel Currently, when we have a process using the transactional memory facilities on POWER8 (that is, the processor is in transactional or suspended state), and the process enters the kernel and the kernel then uses the floating-point or vector (VMX/Altivec) facility, we end up corrupting the user-visible FP/VMX/VSX state. This happens, for example, if a page fault causes a copy-on-write operation, because the copy_page function will use VMX to do the copy on POWER8. The test program below demonstrates the bug. The bug happens because when FP/VMX state for a transactional process is stored in the thread_struct, we store the checkpointed state in .fp_state/.vr_state and the transactional (current) state in .transact_fp/.transact_vr. However, when the kernel wants to use FP/VMX, it calls enable_kernel_fp() or enable_kernel_altivec(), which saves the current state in .fp_state/.vr_state. Furthermore, when we return to the user process we return with FP/VMX/VSX disabled. The next time the process uses FP/VMX/VSX, we don't know which set of state (the current register values, .fp_state/.vr_state, or .transact_fp/.transact_vr) we should be using, since we have no way to tell if we are still in the same transaction, and if not, whether the previous transaction succeeded or failed. Thus it is necessary to strictly adhere to the rule that if FP has been enabled at any point in a transaction, we must keep FP enabled for the user process with the current transactional state in the FP registers, until we detect that it is no longer in a transaction. Similarly for VMX; once enabled it must stay enabled until the process is no longer transactional. In order to keep this rule, we add a new thread_info flag which we test when returning from the kernel to userspace, called TIF_RESTORE_TM. This flag indicates that there is FP/VMX/VSX state to be restored before entering userspace, and when it is set the .tm_orig_msr field in the thread_struct indicates what state needs to be restored. The restoration is done by restore_tm_state(). The TIF_RESTORE_TM bit is set by new giveup_fpu/altivec_maybe_transactional helpers, which are called from enable_kernel_fp/altivec, giveup_vsx, and flush_fp/altivec_to_thread instead of giveup_fpu/altivec. The other thing to be done is to get the transactional FP/VMX/VSX state from .fp_state/.vr_state when doing reclaim, if that state has been saved there by giveup_fpu/altivec_maybe_transactional. Having done this, we set the FP/VMX bit in the thread's MSR after reclaim to indicate that that part of the state is now valid (having been reclaimed from the processor's checkpointed state). Finally, in the signal handling code, we move the clearing of the transactional state bits in the thread's MSR a bit earlier, before calling flush_fp_to_thread(), so that we don't unnecessarily set the TIF_RESTORE_TM bit. This is the test program: /* Michael Neuling 4/12/2013 * * See if the altivec state is leaked out of an aborted transaction due to * kernel vmx copy loops. * * gcc -m64 htm_vmxcopy.c -o htm_vmxcopy * */ /* We don't use all of these, but for reference: */ int main(int argc, char *argv[]) { long double vecin = 1.3; long double vecout; unsigned long pgsize = getpagesize(); int i; int fd; int size = pgsize*16; char tmpfile[] = "/tmp/page_faultXXXXXX"; char buf[pgsize]; char *a; uint64_t aborted = 0; fd = mkstemp(tmpfile); assert(fd >= 0); memset(buf, 0, pgsize); for (i = 0; i < size; i += pgsize) assert(write(fd, buf, pgsize) == pgsize); unlink(tmpfile); a = mmap(NULL, size, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0); assert(a != MAP_FAILED); asm __volatile__( "lxvd2x 40,0,%[vecinptr] ; " // set 40 to initial value TBEGIN "beq 3f ;" TSUSPEND "xxlxor 40,40,40 ; " // set 40 to 0 "std 5, 0(%[map]) ;" // cause kernel vmx copy page TABORT TRESUME TEND "li %[res], 0 ;" "b 5f ;" "3: ;" // Abort handler "li %[res], 1 ;" "5: ;" "stxvd2x 40,0,%[vecoutptr] ; " : [res]"=r"(aborted) : [vecinptr]"r"(&vecin), [vecoutptr]"r"(&vecout), [map]"r"(a) : "memory", "r0", "r3", "r4", "r5", "r6", "r7"); if (aborted && (vecin != vecout)){ printf("FAILED: vector state leaked on abort %f != %f\n", (double)vecin, (double)vecout); exit(1); } munmap(a, size); close(fd); printf("PASSED!\n"); return 0; } Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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#
ec67ad82 |
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24-Nov-2013 |
Michael Neuling <mikey@neuling.org> |
powerpc/signals: Improved mark VSX not saved with small contexts fix In a recent patch: commit c13f20ac48328b05cd3b8c19e31ed6c132b44b42 Author: Michael Neuling <mikey@neuling.org> powerpc/signals: Mark VSX not saved with small contexts We fixed an issue but an improved solution was later discussed after the patch was merged. Firstly, this patch doesn't handle the 64bit signals case, which could also hit this issue (but has never been reported). Secondly, the original patch isn't clear what MSR VSX should be set to. The new approach below always clears the MSR VSX bit (to indicate no VSX is in the context) and sets it only in the specific case where VSX is available (ie. when VSX has been used and the signal context passed has space to provide the state). This reverts the original patch and replaces it with the improved solution. It also adds a 64 bit version. Signed-off-by: Michael Neuling <mikey@neuling.org> Cc: stable@vger.kernel.org Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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#
d606b92a |
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20-Nov-2013 |
Rusty Russell <rusty@rustcorp.com.au> |
powerpc: ELF2 binaries signal handling For the ELFv2 ABI, the hander is the entry point, not a function descriptor. We also need to set up r12, and fortunately the fast_exception_return exit path restores r12 for us so nothing else is required. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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#
de79f7b9 |
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10-Sep-2013 |
Paul Mackerras <paulus@samba.org> |
powerpc: Put FP/VSX and VR state into structures This creates new 'thread_fp_state' and 'thread_vr_state' structures to store FP/VSX state (including FPSCR) and Altivec/VSX state (including VSCR), and uses them in the thread_struct. In the thread_fp_state, the FPRs and VSRs are represented as u64 rather than double, since we rarely perform floating-point computations on the values, and this will enable the structures to be used in KVM code as well. Similarly FPSCR is now a u64 rather than a structure of two 32-bit values. This takes the offsets out of the macros such as SAVE_32FPRS, REST_32FPRS, etc. This enables the same macros to be used for normal and transactional state, enabling us to delete the transactional versions of the macros. This also removes the unused do_load_up_fpu and do_load_up_altivec, which were in fact buggy since they didn't create large enough stack frames to account for the fact that load_up_fpu and load_up_altivec are not designed to be called from C and assume that their caller's stack frame is an interrupt frame. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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#
e871c6bb |
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22-Sep-2013 |
Anton Blanchard <anton@samba.org> |
powerpc: Reset MSR_LE on signal entry We always take signals in big endian which is wrong. Signals should be taken in native endian. Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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#
662499d0 |
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14-Jul-2013 |
Kevin Hao <haokexin@gmail.com> |
powerpc: Remove the redundant flush_fp_to_thread() in setup_sigcontext() In commit c6e6771b(powerpc: Introduce VSX thread_struct and CONFIG_VSX) we add a invocation of flush_fp_to_thread() before copying the FPR or VSR to users. But we already invoke the flush_fp_to_thread() in this function. So remove one of them. Signed-off-by: Kevin Hao <haokexin@gmail.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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#
408a7e08 |
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04-Aug-2013 |
Paul Mackerras <paulus@samba.org> |
powerpc: Fix VRSAVE handling Since 2002, the kernel has not saved VRSAVE on exception entry and restored it on exit; rather, VRSAVE gets context-switched in _switch. This means that when executing in process context in the kernel, the userspace VRSAVE value is live in the VRSAVE register. However, the signal code assumes that current->thread.vrsave holds the current VRSAVE value, which is incorrect. Therefore, this commit changes it to use the actual VRSAVE register instead. (It still uses current->thread.vrsave as a temporary location to store it in, as __get_user and __put_user can only transfer to/from a variable, not an SPR.) This also modifies the transactional memory code to save and restore VRSAVE regardless of whether VMX is enabled in the MSR. This is because accesses to VRSAVE are not controlled by the MSR.VEC bit, but can happen at any time. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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#
b0d436c7 |
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06-Aug-2013 |
Anton Blanchard <anton@samba.org> |
powerpc: Fix a number of sparse warnings Address some of the trivial sparse warnings in arch/powerpc. Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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#
87b4e539 |
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09-Jun-2013 |
Michael Neuling <mikey@neuling.org> |
powerpc/tm: Fix return of active 64bit signals Currently we only restore signals which are transactionally suspended but it's possible that the transaction can be restored even when it's active. Most likely this will result in a transactional rollback by the hardware as the transaction will have been doomed by an earlier treclaim. The current code is a legacy of earlier kernel implementations which did software rollback of active transactions in the kernel. That code has now gone but we didn't correctly fix up this part of the signals code which still makes assumptions based on having software rollback. This changes the signal return code to always restore both contexts on 64 bit signal return. It also ensures that the MSR TM bits are properly restored from the signal context which they are not currently. Signed-off-by: Michael Neuling <mikey@neuling.org> cc: stable@vger.kernel.org (v3.9+) Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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#
2b3f8e87 |
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26-May-2013 |
Michael Neuling <mikey@neuling.org> |
powerpc/tm: Fix userspace stack corruption on signal delivery for active transactions When in an active transaction that takes a signal, we need to be careful with the stack. It's possible that the stack has moved back up after the tbegin. The obvious case here is when the tbegin is called inside a function that returns before a tend. In this case, the stack is part of the checkpointed transactional memory state. If we write over this non transactionally or in suspend, we are in trouble because if we get a tm abort, the program counter and stack pointer will be back at the tbegin but our in memory stack won't be valid anymore. To avoid this, when taking a signal in an active transaction, we need to use the stack pointer from the checkpointed state, rather than the speculated state. This ensures that the signal context (written tm suspended) will be written below the stack required for the rollback. The transaction is aborted becuase of the treclaim, so any memory written between the tbegin and the signal will be rolled back anyway. For signals taken in non-TM or suspended mode, we use the normal/non-checkpointed stack pointer. Tested with 64 and 32 bit signals Signed-off-by: Michael Neuling <mikey@neuling.org> Cc: <stable@vger.kernel.org> # v3.9 Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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#
f110c0c1 |
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09-Apr-2013 |
Michael Neuling <mikey@neuling.org> |
powerpc: fix compiling CONFIG_PPC_TRANSACTIONAL_MEM when CONFIG_ALTIVEC=n We can't compile a kernel with CONFIG_ALTIVEC=n when CONFIG_PPC_TRANSACTIONAL_MEM=y. We currently get: arch/powerpc/kernel/tm.S:320: Error: unsupported relocation against THREAD_VSCR arch/powerpc/kernel/tm.S:323: Error: unsupported relocation against THREAD_VR0 arch/powerpc/kernel/tm.S:323: Error: unsupported relocation against THREAD_VR0 etc. The below fixes this with a sprinkling of #ifdefs. This was found by mpe with kisskb: http://kisskb.ellerman.id.au/kisskb/buildresult/8539442/ Signed-off-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
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#
2b0a576d |
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13-Feb-2013 |
Michael Neuling <mikey@neuling.org> |
powerpc: Add new transactional memory state to the signal context This adds the new transactional memory archtected state to the signal context in both 32 and 64 bit. Signed-off-by: Matt Evans <matt@ozlabs.org> Signed-off-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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#
7cce2465 |
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23-Dec-2012 |
Al Viro <viro@zeniv.linux.org.uk> |
powerpc: switch to generic sigaltstack Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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#
48fc7f7e |
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19-Sep-2012 |
Adam Buchbinder <adam.buchbinder@gmail.com> |
Fix misspellings of "whether" in comments. "Whether" is misspelled in various comments across the tree; this fixes them. No code changes. Signed-off-by: Adam Buchbinder <adam.buchbinder@gmail.com> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
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#
17440f17 |
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27-Apr-2012 |
Al Viro <viro@zeniv.linux.org.uk> |
powerpc: get rid of restore_sigmask() ... it's just a call of set_current_blocked() now Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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#
ae3a197e |
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28-Mar-2012 |
David Howells <dhowells@redhat.com> |
Disintegrate asm/system.h for PowerPC Disintegrate asm/system.h for PowerPC. Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> cc: linuxppc-dev@lists.ozlabs.org
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#
ead53f22 |
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22-Jul-2011 |
Paul Gortmaker <paul.gortmaker@windriver.com> |
powerpc: remove non-required uses of include <linux/module.h> None of the files touched here are modules, and they are not exporting any symbols either -- so there is no need to be including the module.h. Builds of all the files remains successful. Even kernel/module.c does not need to include it, since it includes linux/moduleloader.h instead. Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
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#
76462232 |
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03-Jun-2011 |
Christian Dietrich <christian.dietrich@informatik.uni-erlangen.de> |
arch/powerpc: use printk_ratelimited instead of printk_ratelimit Since printk_ratelimit() shouldn't be used anymore (see comment in include/linux/printk.h), replace it with printk_ratelimited. Signed-off-by: Christian Dietrich <christian.dietrich@informatik.uni-erlangen.de> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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#
9f0b0793 |
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07-Apr-2011 |
Michael Ellerman <michael@ellerman.id.au> |
powerpc: Use MSR_64BIT in places Use the new MSR_64BIT in a few places. Some of these are already ifdef'ed for BOOKE vs BOOKS, but it's still clearer, MSR_SF does not immediately parse as "MSR bit for 64bit". Signed-off-by: Michael Ellerman <michael@ellerman.id.au> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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#
9a81c16b |
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20-Sep-2010 |
Al Viro <viro@zeniv.linux.org.uk> |
powerpc: fix double syscall restarts Make sigreturn zero regs->trap, make do_signal() do the same on all paths. As it is, signal interrupting e.g. read() from fd 512 (== ERESTARTSYS) with another signal getting unblocked when the first handler finishes will lead to restart one insn earlier than it ought to. Same for multiple signals with in-kernel handlers interrupting that sucker at the same time. Same for multiple signals of any kind interrupting that sucker on 64bit... Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Acked-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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#
efbda860 |
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25-Mar-2009 |
Josh Boyer <jwboyer@linux.vnet.ibm.com> |
powerpc: Sanitize stack pointer in signal handling code On powerpc64 machines running 32-bit userspace, we can get garbage bits in the stack pointer passed into the kernel. Most places handle this correctly, but the signal handling code uses the passed value directly for allocating signal stack frames. This fixes the issue by introducing a get_clean_sp function that returns a sanitized stack pointer. For 32-bit tasks on a 64-bit kernel, the stack pointer is masked correctly. In all other cases, the stack pointer is simply returned. Additionally, we pass an 'is_32' parameter to get_sigframe now in order to get the properly sanitized stack. The callers are know to be 32 or 64-bit statically. Signed-off-by: Josh Boyer <jwboyer@linux.vnet.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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#
16c29d18 |
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22-Oct-2008 |
Michael Neuling <mikey@neuling.org> |
powerpc: Fix swapcontext system for VSX + old ucontext size Since VSX support was added, we now have two sizes of ucontext_t; the older, smaller size without the extra VSX state, and the new larger size with the extra VSX state. A program using the sys_swapcontext system call and supplying smaller ucontext_t structures will currently get an EINVAL error if the task has used VSX (e.g. because of calling library code that uses VSX) and the old_ctx argument is non-NULL (i.e. the program is asking for its current context to be saved). Thus the program will start getting EINVAL errors on calls that previously worked. This commit changes this behaviour so that we don't send an EINVAL in this case. It will now return the smaller context but the VSX MSR bit will always be cleared to indicate that the ucontext_t doesn't include the extra VSX state, even if the task has executed VSX instructions. Both 32 and 64 bit cases are updated. [paulus@samba.org - also fix some access_ok() and get_user() calls] Thanks to Ben Herrenschmidt for noticing this problem. Signed-off-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Paul Mackerras <paulus@samba.org>
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#
8873d93b |
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15-Oct-2008 |
Michael Neuling <mikey@neuling.org> |
powerpc: Remove empty #else from signal_64.c Remove empty/bogus #else from signal_64.c Signed-off-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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7c292170 |
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11-Jul-2008 |
Michael Neuling <mikey@neuling.org> |
powerpc: fix giveup_vsx to save registers correctly giveup_vsx didn't save the FPU and VMX regsiters. Change it to be like giveup_fpr/altivec which save these registers. Also update call sites where FPU and VMX are already saved to use the original giveup_vsx (renamed to __giveup_vsx). Signed-off-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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c1cb299e |
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08-Jul-2008 |
Michael Neuling <mikey@neuling.org> |
powerpc: fix swapcontext backwards compat. with VSX ucontext changes When the ucontext changed to add the VSX context, this broke backwards compatibly on swapcontext. swapcontext only compares the ucontext size passed in from the user to the new kernel ucontext size. This adds a check against the old ucontext size (with VMX but without VSX). It also adds some sanity check for ucontexts without VSX, but where VSX is used according the MSR. Fixes for both 32 and 64bit processes on 64bit kernels Kudos to Paulus for noticing. Signed-off-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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6a274c08 |
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01-Jul-2008 |
Michael Neuling <mikey@neuling.org> |
powerpc: Clean up copy_to/from_user for vsx and fpr This merges and cleans up some of the ugly copy/to from user code which is required for the new fpr and vsx layout in the thread_struct. Also fixes some hard coded buffer sizes and removes a redundant fpr_flush_to_thread. Signed-off-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Paul Mackerras <paulus@samba.org>
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436db693 |
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30-Jun-2008 |
Michael Neuling <mikey@neuling.org> |
powerpc: Fix compile error for CONFIG_VSX Fix compile error when CONFIG_VSX is enabled. arch/powerpc/kernel/signal_64.c: In function 'restore_sigcontext': arch/powerpc/kernel/signal_64.c:241: error: 'i' undeclared (first use in this function) Signed-off-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Paul Mackerras <paulus@samba.org>
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fcbc5a97 |
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27-Jun-2008 |
Stephen Rothwell <sfr@canb.auug.org.au> |
powerpc: Explicitly copy elements of pt_regs Gcc 4.3 produced this warning: arch/powerpc/kernel/signal_64.c: In function 'restore_sigcontext': arch/powerpc/kernel/signal_64.c:161: warning: array subscript is above array bounds This is caused by us copying to aliases of elements of the pt_regs structure. Make those explicit. This adds one extra __get_user and unrolls a loop. Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Paul Mackerras <paulus@samba.org>
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ce48b210 |
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24-Jun-2008 |
Michael Neuling <mikey@neuling.org> |
powerpc: Add VSX context save/restore, ptrace and signal support This patch extends the floating point save and restore code to use the VSX load/stores when VSX is available. This will make FP context save/restore marginally slower on FP only code, when VSX is available, as it has to load/store 128bits rather than just 64bits. Mixing FP, VMX and VSX code will get constant architected state. The signals interface is extended to enable access to VSR 0-31 doubleword 1 after discussions with tool chain maintainers. Backward compatibility is maintained. The ptrace interface is also extended to allow access to VSR 0-31 full registers. Signed-off-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Paul Mackerras <paulus@samba.org>
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c6e6771b |
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24-Jun-2008 |
Michael Neuling <mikey@neuling.org> |
powerpc: Introduce VSX thread_struct and CONFIG_VSX The layout of the new VSR registers and how they overlap on top of the legacy FPR and VR registers is: VSR doubleword 0 VSR doubleword 1 ---------------------------------------------------------------- VSR[0] | FPR[0] | | ---------------------------------------------------------------- VSR[1] | FPR[1] | | ---------------------------------------------------------------- | ... | | | ... | | ---------------------------------------------------------------- VSR[30] | FPR[30] | | ---------------------------------------------------------------- VSR[31] | FPR[31] | | ---------------------------------------------------------------- VSR[32] | VR[0] | ---------------------------------------------------------------- VSR[33] | VR[1] | ---------------------------------------------------------------- | ... | | ... | ---------------------------------------------------------------- VSR[62] | VR[30] | ---------------------------------------------------------------- VSR[63] | VR[31] | ---------------------------------------------------------------- VSX has 64 128bit registers. The first 32 regs overlap with the FP registers and hence extend them with and additional 64 bits. The second 32 regs overlap with the VMX registers. This commit introduces the thread_struct changes required to reflect this register layout. Ptrace and signals code is updated so that the floating point registers are correctly accessed from the thread_struct when CONFIG_VSX is enabled. Signed-off-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Paul Mackerras <paulus@samba.org>
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0be234a4 |
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02-Jun-2008 |
Benjamin Herrenschmidt <benh@kernel.crashing.org> |
[POWERPC] Fix incorrect enabling of VMX when building signal or user context When building a signal or a ucontext, we can incorrectly set the MSR_VEC bit of the kernel pt_regs->msr before returning to userspace if the task -ever- used VMX. This can lead to funny result if that stack used it in the past, then "lost" it (ie. it wasn't enabled after a context switch for example) and then called get_context. It can end up with VMX enabled and the registers containing values from some other task. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Paul Mackerras <paulus@samba.org>
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d0c3d534 |
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11-Oct-2007 |
Olof Johansson <olof@lixom.net> |
[POWERPC] Implement logging of unhandled signals Implement show_unhandled_signals sysctl + support to print when a process is killed due to unhandled signals just as i386 and x86_64 does. Default to having it off, unlike x86 that defaults on. Signed-off-by: Olof Johansson <olof@lixom.net> Signed-off-by: Paul Mackerras <paulus@samba.org>
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ae62fbb5 |
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25-Jun-2007 |
Paul Mackerras <paulus@samba.org> |
[POWERPC] Fix subtle FP state corruption bug in signal return on SMP This fixes a bug which can cause corruption of the floating-point state on return from a signal handler. If we have a signal handler that has used the floating-point registers, and it happens to context-switch to another task while copying the interrupted floating-point state from the user stack into the thread struct (e.g. because of a page fault, or because it gets preempted), the context switch code will think that the FP registers contain valid FP state that needs to be copied into the thread_struct, and will thus overwrite the values that the signal return code has put into the thread_struct. This can occur because we clear the MSR bits that indicate the presence of valid FP state after copying the state into the thread_struct. To fix this we just move the clearing of the MSR bits to before the copy. A similar potential problem also occurs with the Altivec state, and this fixes that in the same way. Signed-off-by: Paul Mackerras <paulus@samba.org>
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a3f61dc0 |
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04-Jun-2007 |
Benjamin Herrenschmidt <benh@kernel.crashing.org> |
[POWERPC] Merge creation of signal frame The code for creating signal frames was still duplicated and split in strange ways between 32 and 64 bits, including the SA_ONSTACK handling being in do_signal on 32 bits but inside handle_rt_signal on 64 bits etc... This moves the 64 bits get_sigframe() to the generic signal.c, cleans it a bit, moves the access_ok() call done by all callers to it as well, and adapts/cleanups the 3 different signal handling cases to use that common function. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Paul Mackerras <paulus@samba.org>
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f478f543 |
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03-Jun-2007 |
Christoph Hellwig <hch@lst.de> |
[POWERPC] Consolidate do_signal do_signal has exactly the same behaviour on 32bit and 64bit and 32bit compat on 64bit for handling 32bit signals. Consolidate all these into one common function in signal.c. The only odd left over is the try_to_free in the 32bit version that no other architecture has in mainline (only in i386 for some odd SuSE release). We should probably get rid of it in a separate patch. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Paul Mackerras <paulus@samba.org>
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db277e9a |
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03-Jun-2007 |
Christoph Hellwig <hch@lst.de> |
[POWERPC] Consolidate restore_sigmask restore_sigmask is exactly the same on 32 and 64bit, so move it to common code. Also move _BLOCKABLE to signal.h to avoid defining it multiple times. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Paul Mackerras <paulus@samba.org>
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69d15f6b |
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03-Jun-2007 |
Christoph Hellwig <hch@lst.de> |
[POWERPC] Consolidate sys_sigaltstack sys_sigaltstack is the same on 32bit and 64 and we can consolidate it to signal.c. The only difference is that the 32bit code uses ints for the unused register paramaters and 64bit unsigned long. I've changed it to unsigned long because it's the same width on 32bit. (I also wonder who came up with this awkward calling convention.. :)) Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Paul Mackerras <paulus@samba.org>
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22e38f29 |
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03-Jun-2007 |
Benjamin Herrenschmidt <benh@kernel.crashing.org> |
[POWERPC] Make syscall restart code more common This patch moves the code in signal_32.c and signal_64.c for handling syscall restart into a common signal.c file and converge around a single implementation that is based on the 32 bits one, using trap, ccr and r3 rather than the special "result" field for deciding what to do. The "result" field is now pretty much deprecated. We still set it for the sake of whatever might rely on it in userland but we no longer use it's content. This, along with a previous patch that enables ptracers to write to "trap" and "orig_r3" should allow gdb to properly handle syscall restarting. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Paul Mackerras <paulus@samba.org>
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e63340ae |
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08-May-2007 |
Randy Dunlap <randy.dunlap@oracle.com> |
header cleaning: don't include smp_lock.h when not used Remove includes of <linux/smp_lock.h> where it is not used/needed. Suggested by Al Viro. Builds cleanly on x86_64, i386, alpha, ia64, powerpc, sparc, sparc64, and arm (all 59 defconfigs). Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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6ab3d562 |
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30-Jun-2006 |
Jörn Engel <joern@wohnheim.fh-wedel.de> |
Remove obsolete #include <linux/config.h> Signed-off-by: Jörn Engel <joern@wohnheim.fh-wedel.de> Signed-off-by: Adrian Bunk <bunk@stusta.de>
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fab5db97 |
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07-Jun-2006 |
Paul Mackerras <paulus@samba.org> |
[PATCH] powerpc: Implement support for setting little-endian mode via prctl This adds the PowerPC part of the code to allow processes to change their endian mode via prctl. This also extends the alignment exception handler to be able to fix up alignment exceptions that occur in little-endian mode, both for "PowerPC" little-endian and true little-endian. We always enter signal handlers in big-endian mode -- the support for little-endian mode does not amount to the creation of a little-endian user/kernel ABI. If the signal handler returns, the endian mode is restored to what it was when the signal was delivered. We have two new kernel CPU feature bits, one for PPC little-endian and one for true little-endian. Most of the classic 32-bit processors support PPC little-endian, and this is reflected in the CPU feature table. There are two corresponding feature bits reported to userland in the AT_HWCAP aux vector entry. This is based on an earlier patch by Anton Blanchard. Signed-off-by: Paul Mackerras <paulus@samba.org>
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a5bba930 |
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29-May-2006 |
Benjamin Herrenschmidt <benh@kernel.crashing.org> |
[PATCH] powerpc vdso updates This patch cleans up some locking & error handling in the ppc vdso and moves the vdso base pointer from the thread struct to the mm context where it more logically belongs. It brings the powerpc implementation closer to Ingo's new x86 one and also adds an arch_vma_name() function allowing to print [vsdo] in /proc/<pid>/maps if Ingo's x86 vdso patch is also applied. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Paul Mackerras <paulus@samba.org>
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7c85d1f9 |
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08-Jun-2006 |
Paul Mackerras <paulus@samba.org> |
powerpc: Fix machine check problem on 32-bit kernels This fixes a bug found by Dave Jones that means that it is possible for userspace to provoke a machine check on 32-bit kernels. This also fixes a couple of other places where I found similar problems by inspection. Signed-off-by: Paul Mackerras <paulus@samba.org>
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11089f08 |
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27-Mar-2006 |
Laurent MEYER <meyerlau@fr.ibm.com> |
[PATCH] powerpc: fix incorrect SA_ONSTACK behaviour for 64-bit processes *) When setting a sighandler using sigaction() call, if the flag SA_ONSTACK is set and no alternate stack is provided via sigaltstack(), the kernel still try to install the alternate stack. This behavior is the opposite of the one which is documented in Single Unix Specifications V3. *) Also when setting an alternate stack using sigaltstack() with the flag SS_DISABLE, the kernel try to install the alternate stack on signal delivery. These two use cases makes the process crash at signal delivery. This fixes it. Signed-off-by: Laurent Meyer <meyerlau@fr.ibm.com> Signed-off-by: Paul Mackerras <paulus@samba.org>
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a7f31841 |
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22-Mar-2006 |
Arnd Bergmann <abergman@de.ibm.com> |
[PATCH] powerpc: declare arch syscalls in <asm/syscalls.h> powerpc currently declares some of its own system calls in <asm/unistd.h>, but not all of them. That place also contains remainders of the now almost unused kernel syscall hack. - Add a new <asm/syscalls.h> with clean declarations - Include that file from every source that implements one of these - Get rid of old declarations in <asm/unistd.h> This patch is required as a base for implementing system calls from an SPU, but also makes sense as a general cleanup. Signed-off-by: Arnd Bergmann <arnd.bergmann@de.ibm.com> Signed-off-by: Paul Mackerras <paulus@samba.org>
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1bd79336 |
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07-Mar-2006 |
Paul Mackerras <paulus@samba.org> |
powerpc: Fix various syscall/signal/swapcontext bugs A careful reading of the recent changes to the system call entry/exit paths revealed several problems, plus some things that could be simplified and improved: * 32-bit wasn't testing the _TIF_NOERROR bit in the syscall fast exit path, so it was only doing anything with it once it saw some other bit being set. In other words, the noerror behaviour would apply to the next system call where we had to reschedule or deliver a signal, which is not necessarily the current system call. * 32-bit wasn't doing the call to ptrace_notify in the syscall exit path when the _TIF_SINGLESTEP bit was set. * _TIF_RESTOREALL was in both _TIF_USER_WORK_MASK and _TIF_PERSYSCALL_MASK, which is odd since _TIF_RESTOREALL is only set by system calls. I took it out of _TIF_USER_WORK_MASK. * On 64-bit, _TIF_RESTOREALL wasn't causing the non-volatile registers to be restored (unless perhaps a signal was delivered or the syscall was traced or single-stepped). Thus the non-volatile registers weren't restored on exit from a signal handler. We probably got away with it mostly because signal handlers written in C wouldn't alter the non-volatile registers. * On 32-bit I simplified the code and made it more like 64-bit by making the syscall exit path jump to ret_from_except to handle preemption and signal delivery. * 32-bit was calling do_signal unnecessarily when _TIF_RESTOREALL was set - but I think because of that 32-bit was actually restoring the non-volatile registers on exit from a signal handler. * I changed the order of enabling interrupts and saving the non-volatile registers before calling do_syscall_trace_leave; now we enable interrupts first. Signed-off-by: Paul Mackerras <paulus@samba.org>
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2ef9481e |
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23-Jan-2006 |
Jon Mason <jdmason@us.ibm.com> |
[PATCH] powerpc: trivial: modify comments to refer to new location of files This patch removes all self references and fixes references to files in the now defunct arch/ppc64 tree. I think this accomplises everything wanted, though there might be a few references I missed. Signed-off-by: Jon Mason <jdmason@us.ibm.com> Signed-off-by: Paul Mackerras <paulus@samba.org>
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29e646df |
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01-Feb-2006 |
Al Viro <viro@zeniv.linux.org.uk> |
[PATCH] powerpc signal __user annotations Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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f27201da |
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18-Jan-2006 |
David Woodhouse <dwmw2@infradead.org> |
[PATCH] TIF_RESTORE_SIGMASK support for arch/powerpc Implement the TIF_RESTORE_SIGMASK flag in the new arch/powerpc kernel, for both 32-bit and 64-bit system call paths. Signed-off-by: David Woodhouse <dwmw2@infradead.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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150256d8 |
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18-Jan-2006 |
David Woodhouse <dwmw2@infradead.org> |
[PATCH] Generic sys_rt_sigsuspend() The TIF_RESTORE_SIGMASK flag allows us to have a generic implementation of sys_rt_sigsuspend() instead of duplicating it for each architecture. This provides such an implementation and makes arch/powerpc use it. It also tidies up the ppc32 sys_sigsuspend() to use TIF_RESTORE_SIGMASK. Signed-off-by: David Woodhouse <dwmw2@infradead.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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5388fb10 |
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11-Jan-2006 |
Paul Mackerras <paulus@samba.org> |
[PATCH] powerpc: Avoid potential FP corruption with preempt and UP Heikki Lindholm pointed out that there was a potential race with the lazy CPU state (FP, VR, EVR) stuff if preempt is enabled. The race is that in the process of restoring FP state on sigreturn, the task gets preempted by a user task that wants to use the FPU. It will take an FP unavailable exception, which will write the current FPU state to the thread_struct, overwriting the values which sigreturn has stored. Note that this can only happen on UP since we don't implement lazy CPU state on SMP. The fix is to flush the lazy CPU state before updating the thread_struct. To do this we re-use the flush_lazy_cpu_state() function from process.c. Signed-off-by: Paul Mackerras <paulus@samba.org>
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401d1f02 |
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15-Nov-2005 |
David Woodhouse <dwmw2@infradead.org> |
[PATCH] syscall entry/exit revamp This cleanup patch speeds up the null syscall path on ppc64 by about 3%, and brings the ppc32 and ppc64 code slightly closer together. The ppc64 code was checking current_thread_info()->flags twice in the syscall exit path; once for TIF_SYSCALL_T_OR_A before disabling interrupts, and then again for TIF_SIGPENDING|TIF_NEED_RESCHED etc after disabling interrupts. Now we do the same as ppc32 -- check the flags only once in the fast path, and re-enable interrupts if necessary in the ptrace case. The patch abolishes the 'syscall_noerror' member of struct thread_info and replaces it with a TIF_NOERROR bit in the flags, which is handled in the slow path. This shortens the syscall entry code, which no longer needs to clear syscall_noerror. The patch adds a TIF_SAVE_NVGPRS flag which causes the syscall exit slow path to save the non-volatile GPRs into a signal frame. This removes the need for the assembly wrappers around sys_sigsuspend(), sys_rt_sigsuspend(), et al which existed solely to save those registers in advance. It also means I don't have to add new wrappers for ppoll() and pselect(), which is what I was supposed to be doing when I got distracted into this... Finally, it unifies the ppc64 and ppc32 methods of handling syscall exit directly into a signal handler (as required by sigsuspend et al) by introducing a TIF_RESTOREALL flag which causes _all_ the registers to be reloaded from the pt_regs by taking the ret_from_exception path, instead of the normal syscall exit path which stomps on the callee-saved GPRs. It appears to pass an LTP test run on ppc64, and passes basic testing on ppc32 too. Brief tests of ptrace functionality with strace and gdb also appear OK. I wouldn't send it to Linus for 2.6.15 just yet though :) Signed-off-by: David Woodhouse <dwmw2@infradead.org> Signed-off-by: Paul Mackerras <paulus@samba.org>
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cc657f53 |
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14-Nov-2005 |
Paul Mackerras <paulus@samba.org> |
powerpc: Fix clearing of the FPSCR when invoking a signal handler As pointed out by Gary Byers, we were clearing the image of the FPSCR (floating point status and control register) in the thread_struct before copying it to the user stack when invoking a signal. Thus the task would see its FPSCR getting cleared when it took a signal. While fixing it I noticed that our swapcontext system call was also clearing FPSCR. It shouldn't, so I fixed that too. Signed-off-by: Paul Mackerras <paulus@samba.org>
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dcad47fc |
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06-Nov-2005 |
David Gibson <david@gibson.dropbear.id.au> |
[PATCH] powerpc: Kill ppcdebug The ancient ppcdebug/PPCDBG mechanism is now only used in two places. First, in the hash setup code, one of the bits allows the size of the hash table to be reduced by a factor of 8 - which would be better accomplished with a command line option for that purpose. The other was a bunch of bus walking related messages in the iSeries code, which would seem to be insufficient reason to keep the mechanism. This patch removes the last traces of this mechanism. Built and booted on iSeries and pSeries POWER5 LPAR (ARCH=powerpc). Signed-off-by: David Gibson <dwg@au1.ibm.com> Signed-off-by: Paul Mackerras <paulus@samba.org>
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62f4f47d |
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02-Nov-2005 |
Stephen Rothwell <sfr@canb.auug.org.au> |
powerpc: move ppc64/kernel/signal.c to arch/powerpc Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
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