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x86/ftrace: Remove ftrace_epilogue()

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Remove the weird jumps to RET and simply use RET.

This then promotes ftrace_stub() to a real function; which becomes
important for kcfi.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20220915111148.719080593@infradead.org
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
This commit is contained in:
Peter Zijlstra 2022-09-15 13:11:35 +02:00
parent 67bf649344
commit b5f1fc3184
1 changed files with 6 additions and 15 deletions
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21
arch/x86/kernel/ftrace_64.S
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@ -172,20 +172,14 @@ SYM_INNER_LABEL(ftrace_call, SYM_L_GLOBAL)
*/
SYM_INNER_LABEL(ftrace_caller_end, SYM_L_GLOBAL)
ANNOTATE_NOENDBR
jmp ftrace_epilogue
RET
SYM_FUNC_END(ftrace_caller);
STACK_FRAME_NON_STANDARD_FP(ftrace_caller)
SYM_FUNC_START(ftrace_epilogue)
/*
* This is weak to keep gas from relaxing the jumps.
*/
SYM_INNER_LABEL_ALIGN(ftrace_stub, SYM_L_WEAK)
SYM_FUNC_START(ftrace_stub)
UNWIND_HINT_FUNC
ENDBR
RET
SYM_FUNC_END(ftrace_epilogue)
SYM_FUNC_END(ftrace_stub)
SYM_FUNC_START(ftrace_regs_caller)
/* Save the current flags before any operations that can change them */
@ -262,14 +256,11 @@ SYM_INNER_LABEL(ftrace_regs_caller_jmp, SYM_L_GLOBAL)
popfq
/*
* As this jmp to ftrace_epilogue can be a short jump
* it must not be copied into the trampoline.
* The trampoline will add the code to jump
* to the return.
* The trampoline will add the return.
*/
SYM_INNER_LABEL(ftrace_regs_caller_end, SYM_L_GLOBAL)
ANNOTATE_NOENDBR
jmp ftrace_epilogue
RET
/* Swap the flags with orig_rax */
1: movq MCOUNT_REG_SIZE(%rsp), %rdi
@ -280,7 +271,7 @@ SYM_INNER_LABEL(ftrace_regs_caller_end, SYM_L_GLOBAL)
/* Restore flags */
popfq
UNWIND_HINT_FUNC
jmp ftrace_epilogue
RET
SYM_FUNC_END(ftrace_regs_caller)
STACK_FRAME_NON_STANDARD_FP(ftrace_regs_caller)