vmlinux.o: warning: objtool: fixup_bad_iret()+0x8e: call to memcpy() leaves
.noinstr.text section
Worse, when KASAN there is no telling what memcpy() actually is. Force
the use of __memcpy() which is our assmebly implementation.
Reported-by: Marco Elver <el...@google.com>
Suggested-by: Marco Elver <el...@google.com>
Signed-off-by: Peter Zijlstra (Intel) <pet...@infradead.org>
---
arch/x86/kernel/traps.c | 6 +++---
arch/x86/lib/memcpy_64.S | 4 ++++
2 files changed, 7 insertions(+), 3 deletions(-)
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -685,13 +685,13 @@ struct bad_iret_stack *fixup_bad_iret(st
(struct bad_iret_stack
*)__this_cpu_read(cpu_tss_rw.x86_tss.sp0) - 1;
/* Copy the IRET target to the temporary storage. */
- memcpy(&tmp.regs.ip, (void *)s->regs.sp, 5*8);
+ __memcpy(&tmp.regs.ip, (void *)s->regs.sp, 5*8);
/* Copy the remainder of the stack from the current stack. */
- memcpy(&tmp, s, offsetof(struct bad_iret_stack, regs.ip));
+ __memcpy(&tmp, s, offsetof(struct bad_iret_stack, regs.ip));
/* Update the entry stack */
- memcpy(new_stack, &tmp, sizeof(tmp));
+ __memcpy(new_stack, &tmp, sizeof(tmp));
BUG_ON(!user_mode(&new_stack->regs));
return new_stack;
--- a/arch/x86/lib/memcpy_64.S
+++ b/arch/x86/lib/memcpy_64.S
@@ -8,6 +8,8 @@
#include <asm/alternative-asm.h>
#include <asm/export.h>
+.pushsection .noinstr.text, "ax"
+
/*
* We build a jump to memcpy_orig by default which gets NOPped out on
* the majority of x86 CPUs which set REP_GOOD. In addition, CPUs which
@@ -184,6 +186,8 @@ SYM_FUNC_START_LOCAL(memcpy_orig)
retq
SYM_FUNC_END(memcpy_orig)
+.popsection
+
#ifndef CONFIG_UML
MCSAFE_TEST_CTL
