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ae24db43 |
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08-Dec-2023 |
Naveen N Rao <naveen@kernel.org> |
powerpc/ftrace: Remove nops after the call to ftrace_stub ftrace_stub is within the same CU, so there is no need for a subsequent nop instruction. Signed-off-by: Naveen N Rao <naveen@kernel.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://msgid.link/8ee5ec520e37d5523654bb2cd65a17512fb774e2.1702045299.git.naveen@kernel.org
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4b3338aa |
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29-Nov-2023 |
Naveen N Rao <naveen@kernel.org> |
powerpc/ftrace: Fix stack teardown in ftrace_no_trace Commit 41a506ef71eb ("powerpc/ftrace: Create a dummy stackframe to fix stack unwind") added use of a new stack frame on ftrace entry to fix stack unwind. However, the commit missed updating the offset used while tearing down the ftrace stack when ftrace is disabled. Fix the same. In addition, the commit missed saving the correct stack pointer in pt_regs. Update the same. Fixes: 41a506ef71eb ("powerpc/ftrace: Create a dummy stackframe to fix stack unwind") Cc: stable@vger.kernel.org # v6.5+ Signed-off-by: Naveen N Rao <naveen@kernel.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://msgid.link/20231130065947.2188860-1-naveen@kernel.org
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0f71dcfb |
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19-Jun-2023 |
Naveen N Rao <naveen@kernel.org> |
powerpc/ftrace: Add support for -fpatchable-function-entry GCC v13.1 updated support for -fpatchable-function-entry on ppc64le to emit nops after the local entry point, rather than before it. This allows us to use this in the kernel for ftrace purposes. A new script is added under arch/powerpc/tools/ to help detect if nops are emitted after the function local entry point, or before the global entry point. With -fpatchable-function-entry, we no longer have the profiling instructions generated at function entry, so we only need to validate the presence of two nops at the ftrace location in ftrace_init_nop(). We patch the preceding instruction with 'mflr r0' to match the -mprofile-kernel ABI for subsequent ftrace use. This changes the profiling instructions used on ppc32. The default -pg option emits an additional 'stw' instruction after 'mflr r0' and before the branch to _mcount 'bl _mcount'. This is very similar to the original -mprofile-kernel implementation on ppc64le, where an additional 'std' instruction was used to save LR to its save location in the caller's stackframe. Subsequently, this additional store was removed in later compiler versions for performance reasons. The same reasons apply for ppc32 so we only patch in a 'mflr r0'. Signed-off-by: Naveen N Rao <naveen@kernel.org> Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://msgid.link/68586d22981a2c3bb45f27a2b621173d10a7d092.1687166935.git.naveen@kernel.org
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bad90aa5 |
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19-Jun-2023 |
Naveen N Rao <naveen@kernel.org> |
powerpc/ftrace: Consolidate ftrace support into fewer files ftrace_low.S has just the _mcount stub and return_to_handler(). Merge this back into ftrace_mprofile.S and ftrace_64_pg.S to keep all ftrace code together, and to allow those to evolve independently. ftrace_mprofile.S is also not an entirely accurate name since this also holds ppc32 code. This will be all the more incorrect once support for -fpatchable-function-entry is added. Rename files here to more accurately describe the code: - ftrace_mprofile.S is renamed to ftrace_entry.S - ftrace_pg.c is renamed to ftrace_64_pg.c - ftrace_64_pg.S is rename to ftrace_64_pg_entry.S Signed-off-by: Naveen N Rao <naveen@kernel.org> Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://msgid.link/b900c9a8bba9d6c3c295e0f99886acf3e5bf6f7b.1687166935.git.naveen@kernel.org
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