x86/callthunks: Mark apply_relocation() as __init_or_module

Do it like the rest of the methods using it.

Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Uros Bizjak <ubizjak@gmail.com>
Link: https://lore.kernel.org/r/20231105213731.1878100-3-ubizjak@gmail.com

x86/callthunks: Handle %rip-relative relocations in call thunk template

Contrary to alternatives, relocations are currently not supported in
call thunk templates. Re-use the existing infrastructure from
alternative.c to allow %rip-relative relocations when copying call
thunk template from its storage location.

The patch allows unification of ASM_INCREMENT_CALL_DEPTH, which already
uses PER_CPU_VAR macro, with INCREMENT_CALL_DEPTH, used in call thunk
template, which is currently limited to use absolute address.

Reuse existing relocation infrastructure from alternative.c.,
as suggested by Peter Zijlstra.

Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20231105213731.1878100-3-ubizjak@gmail.com

x86/paravirt: Remove no longer needed paravirt patching code

Now that paravirt is using the alternatives patching infrastructure,
remove the paravirt patching code.

Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20231210062138.2417-6-jgross@suse.com

x86/alternatives: Introduce int3_emulate_jcc()

Move the kprobe Jcc emulation into int3_emulate_jcc() so it can be
used by more code -- specifically static_call() will need this.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Link: https://lore.kernel.org/r/20230123210607.057678245@infradead.org

x86/alternatives: Provide text_poke_copy_locked()

The upcoming call thunk patching must hold text_mutex and needs access to
text_poke_copy(), which takes text_mutex.

Provide a _locked postfixed variant to expose the inner workings.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20220915111147.159977224@infradead.org

x86/alternative: Introduce text_poke_set

Introduce a memset like API for text_poke. This will be used to fill the
unused RX memory with illegal instructions.

Suggested-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Song Liu <song@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/bpf/20220520235758.1858153-3-song@kernel.org

x86/ibt,paravirt: Use text_gen_insn() for paravirt_patch()

Less duplication is more better.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lore.kernel.org/r/20220308154317.697253958@infradead.org

x86/text-patching: Make text_gen_insn() play nice with ANNOTATE_NOENDBR

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lore.kernel.org/r/20220308154317.638561109@infradead.org

x86/alternative: Introduce text_poke_copy

This will be used by BPF jit compiler to dump JITed binary to a RX huge
page, and thus allow multiple BPF programs sharing the a huge (2MB) page.

Signed-off-by: Song Liu <song@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/bpf/20220204185742.271030-6-song@kernel.org

x86/alternatives: Teach text_poke_bp() to emulate RET

Future patches will need to poke a RET instruction, provide the
infrastructure required for this.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Link: https://lore.kernel.org/r/20200818135804.982214828@infradead.org

x86/int3: Ensure that poke_int3_handler() is not traced

In order to ensure poke_int3_handler() is completely self contained -- this
is called while modifying other text, imagine the fun of hitting another
INT3 -- ensure that everything it uses is not traced.

The primary means here is to force inlining; bsearch() is notrace because
all of lib/ is.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Acked-by: Andy Lutomirski <luto@kernel.org>
Link: https://lkml.kernel.org/r/20200505135313.410702173@linutronix.de

x86/kprobes: Fix ordering while text-patching

Kprobes does something like:

register:
arch_arm_kprobe()
text_poke(INT3)
/* guarantees nothing, INT3 will become visible at some point, maybe */

kprobe_optimizer()
/* guarantees the bytes after INT3 are unused */
synchronize_rcu_tasks();
text_poke_bp(JMP32);
/* implies IPI-sync, kprobe really is enabled */

unregister:
__disarm_kprobe()
unoptimize_kprobe()
text_poke_bp(INT3 + tail);
/* implies IPI-sync, so tail is guaranteed visible */
arch_disarm_kprobe()
text_poke(old);
/* guarantees nothing, old will maybe become visible */

synchronize_rcu()

free-stuff

Now the problem is that on register, the synchronize_rcu_tasks() does
not imply sufficient to guarantee all CPUs have already observed INT3
(although in practice this is exceedingly unlikely not to have
happened) (similar to how MEMBARRIER_CMD_PRIVATE_EXPEDITED does not
imply MEMBARRIER_CMD_PRIVATE_EXPEDITED_SYNC_CORE).

Worse, even if it did, we'd have to do 2 synchronize calls to provide
the guarantee we're looking for, the first to ensure INT3 is visible,
the second to guarantee nobody is then still using the instruction
bytes after INT3.

Similar on unregister; the synchronize_rcu() between
__unregister_kprobe_top() and __unregister_kprobe_bottom() does not
guarantee all CPUs are free of the INT3 (and observe the old text).

Therefore, sprinkle some IPI-sync love around. This guarantees that
all CPUs agree on the text and RCU once again provides the required
guaranteed.

Tested-by: Alexei Starovoitov <ast@kernel.org>
Tested-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Paul E. McKenney <paulmck@kernel.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20191111132458.162172862@infradead.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

x86/kprobes: Convert to text-patching.h

Convert kprobes to the new text-poke naming.

Tested-by: Alexei Starovoitov <ast@kernel.org>
Tested-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20191111132458.103959370@infradead.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

x86/ftrace: Use text_gen_insn()

Replace the ftrace_code_union with the generic text_gen_insn() helper,
which does exactly this.

Tested-by: Alexei Starovoitov <ast@kernel.org>
Tested-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20191111132457.932808000@infradead.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

x86/alternative: Add text_opcode_size()

Introduce a common helper to map *_INSN_OPCODE to *_INSN_SIZE.

Tested-by: Alexei Starovoitov <ast@kernel.org>
Tested-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20191111132457.875666061@infradead.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

x86/alternatives: Add and use text_gen_insn() helper

Provide a simple helper function to create common instruction
encodings.

Tested-by: Alexei Starovoitov <ast@kernel.org>
Tested-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Daniel Bristot de Oliveira <bristot@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20191111132457.703538332@infradead.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

x86/alternatives, jump_label: Provide better text_poke() batching interface

Adding another text_poke_bp_batch() user made me realize the interface
is all sorts of wrong. The text poke vector should be internal to the
implementation.

This then results in a trivial interface:

text_poke_queue() - which has the 'normal' text_poke_bp() interface
text_poke_finish() - which takes no arguments and flushes any
pending text_poke()s.

Tested-by: Alexei Starovoitov <ast@kernel.org>
Tested-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
Reviewed-by: Daniel Bristot de Oliveira <bristot@redhat.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20191111132457.646280715@infradead.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

x86/alternatives: Update int3_emulate_push() comment

Update the comment now that we've merged x86_32 support.

Tested-by: Alexei Starovoitov <ast@kernel.org>
Tested-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20191111132457.588386013@infradead.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

x86/alternatives: Teach text_poke_bp() to emulate instructions

In preparation for static_call and variable size jump_label support,
teach text_poke_bp() to emulate instructions, namely:

JMP32, JMP8, CALL, NOP2, NOP_ATOMIC5, INT3

The current text_poke_bp() takes a @handler argument which is used as
a jump target when the temporary INT3 is hit by a different CPU.

When patching CALL instructions, this doesn't work because we'd miss
the PUSH of the return address. Instead, teach poke_int3_handler() to
emulate an instruction, typically the instruction we're patching in.

This fits almost all text_poke_bp() users, except
arch_unoptimize_kprobe() which restores random text, and for that site
we have to build an explicit emulate instruction.

Tested-by: Alexei Starovoitov <ast@kernel.org>
Tested-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
Reviewed-by: Daniel Bristot de Oliveira <bristot@redhat.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20191111132457.529086974@infradead.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
(cherry picked from commit 8c7eebc10687af45ac8e40ad1bac0cf7893dba9f)
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

x86: Correct misc typos

Correct spelling typos in comments in different files under arch/x86/.

[ bp: Merge into a single patch, massage. ]

Signed-off-by: Marco Ammon <marco.ammon@fau.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Daniel Bristot de Oliveira <bristot@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Nadav Amit <namit@vmware.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Pu Wen <puwen@hygon.cn>
Cc: Rick Edgecombe <rick.p.edgecombe@intel.com>
Cc: "Steven Rostedt (VMware)" <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: trivial@kernel.org
Cc: x86-ml <x86@kernel.org>
Link: https://lkml.kernel.org/r/20190902102436.27396-1-marco.ammon@fau.de

x86/stackframe/32: Allow int3_emulate_push()

Now that x86_32 has an unconditional gap on the kernel stack frame,
the int3_emulate_push() thing will work without further changes.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>

x86/alternative: Batch of patch operations

Currently, the patch of an address is done in three steps:

-- Pseudo-code #1 - Current implementation ---

1) add an int3 trap to the address that will be patched
sync cores (send IPI to all other CPUs)
2) update all but the first byte of the patched range
sync cores (send IPI to all other CPUs)
3) replace the first byte (int3) by the first byte of replacing opcode
sync cores (send IPI to all other CPUs)

-- Pseudo-code #1 ---

When a static key has more than one entry, these steps are called once for
each entry. The number of IPIs then is linear with regard to the number 'n' of
entries of a key: O(n*3), which is O(n).

This algorithm works fine for the update of a single key. But we think
it is possible to optimize the case in which a static key has more than
one entry. For instance, the sched_schedstats jump label has 56 entries
in my (updated) fedora kernel, resulting in 168 IPIs for each CPU in
which the thread that is enabling the key is _not_ running.

With this patch, rather than receiving a single patch to be processed, a vector
of patches is passed, enabling the rewrite of the pseudo-code #1 in this
way:

-- Pseudo-code #2 - This patch ---
1) for each patch in the vector:
add an int3 trap to the address that will be patched

sync cores (send IPI to all other CPUs)

2) for each patch in the vector:
update all but the first byte of the patched range

sync cores (send IPI to all other CPUs)

3) for each patch in the vector:
replace the first byte (int3) by the first byte of replacing opcode

sync cores (send IPI to all other CPUs)
-- Pseudo-code #2 - This patch ---

Doing the update in this way, the number of IPI becomes O(3) with regard
to the number of keys, which is O(1).

The batch mode is done with the function text_poke_bp_batch(), that receives
two arguments: a vector of "struct text_to_poke", and the number of entries
in the vector.

The vector must be sorted by the addr field of the text_to_poke structure,
enabling the binary search of a handler in the poke_int3_handler function
(a fast path).

Signed-off-by: Daniel Bristot de Oliveira <bristot@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Chris von Recklinghausen <crecklin@redhat.com>
Cc: Clark Williams <williams@redhat.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jason Baron <jbaron@akamai.com>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Scott Wood <swood@redhat.com>
Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/ca506ed52584c80f64de23f6f55ca288e5d079de.1560325897.git.bristot@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

x86: Hide the int3_emulate_call/jmp functions from UML

User Mode Linux does not have access to the ip or sp fields of the pt_regs,
and accessing them causes UML to fail to build. Hide the int3_emulate_jmp()
and int3_emulate_call() instructions from UML, as it doesn't need them
anyway.

Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

x86_64: Allow breakpoints to emulate call instructions

In order to allow breakpoints to emulate call instructions, they need to push
the return address onto the stack. The x86_64 int3 handler adds a small gap
to allow the stack to grow some. Use this gap to add the return address to
be able to emulate a call instruction at the breakpoint location.

These helper functions are added:

int3_emulate_jmp(): changes the location of the regs->ip to return there.

(The next two are only for x86_64)
int3_emulate_push(): to push the address onto the gap in the stack
int3_emulate_call(): push the return address and change regs->ip

Cc: Andy Lutomirski <luto@kernel.org>
Cc: Nicolai Stange <nstange@suse.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: the arch/x86 maintainers <x86@kernel.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Jiri Kosina <jikos@kernel.org>
Cc: Miroslav Benes <mbenes@suse.cz>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Joe Lawrence <joe.lawrence@redhat.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Mimi Zohar <zohar@linux.ibm.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Nayna Jain <nayna@linux.ibm.com>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: Joerg Roedel <jroedel@suse.de>
Cc: "open list:KERNEL SELFTEST FRAMEWORK" <linux-kselftest@vger.kernel.org>
Cc: stable@vger.kernel.org
Fixes: b700e7f03df5 ("livepatch: kernel: add support for live patching")
Tested-by: Nicolai Stange <nstange@suse.de>
Reviewed-by: Nicolai Stange <nstange@suse.de>
Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
[ Modified to only work for x86_64 and added comment to int3_emulate_push() ]
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

x86/alternatives: Remove the return value of text_poke_*()

The return value of text_poke_early() and text_poke_bp() is useless.
Remove it.

Signed-off-by: Nadav Amit <namit@vmware.com>
Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: <akpm@linux-foundation.org>
Cc: <ard.biesheuvel@linaro.org>
Cc: <deneen.t.dock@intel.com>
Cc: <kernel-hardening@lists.openwall.com>
Cc: <kristen@linux.intel.com>
Cc: <linux_dti@icloud.com>
Cc: <will.deacon@arm.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20190426001143.4983-14-namit@vmware.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

x86/alternatives: Initialize temporary mm for patching

To prevent improper use of the PTEs that are used for text patching, the
next patches will use a temporary mm struct. Initailize it by copying
the init mm.

The address that will be used for patching is taken from the lower area
that is usually used for the task memory. Doing so prevents the need to
frequently synchronize the temporary-mm (e.g., when BPF programs are
installed), since different PGDs are used for the task memory.

Finally, randomize the address of the PTEs to harden against exploits
that use these PTEs.

Suggested-by: Andy Lutomirski <luto@kernel.org>
Tested-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Nadav Amit <namit@vmware.com>
Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: akpm@linux-foundation.org
Cc: ard.biesheuvel@linaro.org
Cc: deneen.t.dock@intel.com
Cc: kernel-hardening@lists.openwall.com
Cc: kristen@linux.intel.com
Cc: linux_dti@icloud.com
Cc: will.deacon@arm.com
Link: https://lkml.kernel.org/r/20190426232303.28381-8-nadav.amit@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

x86/alternatives: Add text_poke_kgdb() to not assert the lock when debugging

text_mutex is currently expected to be held before text_poke() is
called, but kgdb does not take the mutex, and instead *supposedly*
ensures the lock is not taken and will not be acquired by any other core
while text_poke() is running.

The reason for the "supposedly" comment is that it is not entirely clear
that this would be the case if gdb_do_roundup is zero.

Create two wrapper functions, text_poke() and text_poke_kgdb(), which do
or do not run the lockdep assertion respectively.

While we are at it, change the return code of text_poke() to something
meaningful. One day, callers might actually respect it and the existing
BUG_ON() when patching fails could be removed. For kgdb, the return
value can actually be used.

Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Nadav Amit <namit@vmware.com>
Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
Acked-by: Jiri Kosina <jkosina@suse.cz>
Cc: <akpm@linux-foundation.org>
Cc: <ard.biesheuvel@linaro.org>
Cc: <deneen.t.dock@intel.com>
Cc: <kernel-hardening@lists.openwall.com>
Cc: <kristen@linux.intel.com>
Cc: <linux_dti@icloud.com>
Cc: <will.deacon@arm.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: 9222f606506c ("x86/alternatives: Lockdep-enforce text_mutex in text_poke*()")
Link: https://lkml.kernel.org/r/20190426001143.4983-2-namit@vmware.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

x86/alternatives, jumplabel: Use text_poke_early() before mm_init()

It supposed to be safe to modify static branches after jump_label_init().
But, because static key modifying code eventually calls text_poke() it can
end up accessing a struct page which has not been initialized yet.

Here is how to quickly reproduce the problem. Insert code like this
into init/main.c:

| +static DEFINE_STATIC_KEY_FALSE(__test);
| asmlinkage __visible void __init start_kernel(void)
| {
| char *command_line;
|@@ -587,6 +609,10 @@ asmlinkage __visible void __init start_kernel(void)
| vfs_caches_init_early();
| sort_main_extable();
| trap_init();
|+ {
|+ static_branch_enable(&__test);
|+ WARN_ON(!static_branch_likely(&__test));
|+ }
| mm_init();

The following warnings show-up:
WARNING: CPU: 0 PID: 0 at arch/x86/kernel/alternative.c:701 text_poke+0x20d/0x230
RIP: 0010:text_poke+0x20d/0x230
Call Trace:
? text_poke_bp+0x50/0xda
? arch_jump_label_transform+0x89/0xe0
? __jump_label_update+0x78/0xb0
? static_key_enable_cpuslocked+0x4d/0x80
? static_key_enable+0x11/0x20
? start_kernel+0x23e/0x4c8
? secondary_startup_64+0xa5/0xb0

---[ end trace abdc99c031b8a90a ]---

If the code above is moved after mm_init(), no warning is shown, as struct
pages are initialized during handover from memblock.

Use text_poke_early() in static branching until early boot IRQs are enabled
and from there switch to text_poke. Also, ensure text_poke() is never
invoked when unitialized memory access may happen by using adding a
!after_bootmem assertion.

Signed-off-by: Pavel Tatashin <pasha.tatashin@oracle.com>
Cc: steven.sistare@oracle.com
Cc: daniel.m.jordan@oracle.com
Cc: linux@armlinux.org.uk
Cc: schwidefsky@de.ibm.com
Cc: heiko.carstens@de.ibm.com
Cc: john.stultz@linaro.org
Cc: sboyd@codeaurora.org
Cc: hpa@zytor.com
Cc: douly.fnst@cn.fujitsu.com
Cc: peterz@infradead.org
Cc: prarit@redhat.com
Cc: feng.tang@intel.com
Cc: pmladek@suse.com
Cc: gnomes@lxorguk.ukuu.org.uk
Cc: linux-s390@vger.kernel.org
Cc: boris.ostrovsky@oracle.com
Cc: jgross@suse.com
Cc: pbonzini@redhat.com
Link: https://lkml.kernel.org/r/20180719205545.16512-9-pasha.tatashin@oracle.com

License cleanup: add SPDX GPL-2.0 license identifier to files with no license

Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.

By default all files without license information are under the default
license of the kernel, which is GPL version 2.

Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier. The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.

This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.

How this work was done:

Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
- file had no licensing information it it.
- file was a */uapi/* one with no licensing information in it,
- file was a */uapi/* one with existing licensing information,

Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.

The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne. Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.

The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed. Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.

Criteria used to select files for SPDX license identifier tagging was:
- Files considered eligible had to be source code files.
- Make and config files were included as candidates if they contained >5
lines of source
- File already had some variant of a license header in it (even if <5
lines).

All documentation files were explicitly excluded.

The following heuristics were used to determine which SPDX license
identifiers to apply.

- when both scanners couldn't find any license traces, file was
considered to have no license information in it, and the top level
COPYING file license applied.

For non */uapi/* files that summary was:

SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 11139

and resulted in the first patch in this series.

If that file was a */uapi/* path one, it was "GPL-2.0 WITH
Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was:

SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 WITH Linux-syscall-note 930

and resulted in the second patch in this series.

- if a file had some form of licensing information in it, and was one
of the */uapi/* ones, it was denoted with the Linux-syscall-note if
any GPL family license was found in the file or had no licensing in
it (per prior point). Results summary:

SPDX license identifier # files
---------------------------------------------------|------
GPL-2.0 WITH Linux-syscall-note 270
GPL-2.0+ WITH Linux-syscall-note 169
((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21
((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17
LGPL-2.1+ WITH Linux-syscall-note 15
GPL-1.0+ WITH Linux-syscall-note 14
((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5
LGPL-2.0+ WITH Linux-syscall-note 4
LGPL-2.1 WITH Linux-syscall-note 3
((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3
((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1

and that resulted in the third patch in this series.

- when the two scanners agreed on the detected license(s), that became
the concluded license(s).

- when there was disagreement between the two scanners (one detected a
license but the other didn't, or they both detected different
licenses) a manual inspection of the file occurred.

- In most cases a manual inspection of the information in the file
resulted in a clear resolution of the license that should apply (and
which scanner probably needed to revisit its heuristics).

- When it was not immediately clear, the license identifier was
confirmed with lawyers working with the Linux Foundation.

- If there was any question as to the appropriate license identifier,
the file was flagged for further research and to be revisited later
in time.

In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.

Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights. The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.

Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.

In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.

Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
- a full scancode scan run, collecting the matched texts, detected
license ids and scores
- reviewing anything where there was a license detected (about 500+
files) to ensure that the applied SPDX license was correct
- reviewing anything where there was no detection but the patch license
was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
SPDX license was correct

This produced a worksheet with 20 files needing minor correction. This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.

These .csv files were then reviewed by Greg. Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected. This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.) Finally Greg ran the script using the .csv files to
generate the patches.

Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

x86/asm: Stop depending on ptrace.h in alternative.h

alternative.h pulls in ptrace.h, which means that alternatives can't
be used in anything referenced from ptrace.h, which is a mess.

Break the dependency by pulling text patching helpers into their own
header.

Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/99b93b13f2c9eb671f5c98bba4c2cbdc061293a2.1461698311.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>