[tip: core/kprobes] x86/alternatives: Update int3_emulate_push() comment

[tip-bot2 for Peter Zijlstra]

The following commit has been merged into the core/kprobes branch of tip:

Commit-ID:     8959eb6ef5b86512452ef3bad167511dace61d84
Gitweb:        https://git.kernel.org/tip/8959eb6ef5b86512452ef3bad167511dace61d84
Author:        Peter Zijlstra <peterz@xxxxxxxxxxxxx>
AuthorDate:    Tue, 03 Sep 2019 13:43:24 +02:00
Committer:     Ingo Molnar <mingo@xxxxxxxxxx>
CommitterDate: Fri, 15 Nov 2019 09:07:41 +01:00

x86/alternatives: Update int3_emulate_push() comment

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

Tested-by: Alexei Starovoitov <ast@xxxxxxxxxx>
Tested-by: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Acked-by: Alexei Starovoitov <ast@xxxxxxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: H. Peter Anvin <hpa@xxxxxxxxx>
Cc: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Link: https://lkml.kernel.org/r/20191111132457.588386013@xxxxxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
 arch/x86/include/asm/text-patching.h | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/arch/x86/include/asm/text-patching.h b/arch/x86/include/asm/text-patching.h
index 23c626a..ea91049 100644
--- a/arch/x86/include/asm/text-patching.h
+++ b/arch/x86/include/asm/text-patching.h
@@ -85,6 +85,9 @@ static inline void int3_emulate_push(struct pt_regs *regs, unsigned long val)
 	 * stack where the break point happened, and the saving of
 	 * pt_regs. We can extend the original stack because of
 	 * this gap. See the idtentry macro's create_gap option.
+	 *
+	 * Similarly entry_32.S will have a gap on the stack for (any) hardware
+	 * exception and pt_regs; see FIXUP_FRAME.
 	 */
 	regs->sp -= sizeof(unsigned long);
 	*(unsigned long *)regs->sp = val;