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authorPeter Zijlstra <peterz@infradead.org>2020-06-17 18:21:16 +0200
committerPeter Zijlstra <peterz@infradead.org>2020-06-25 13:45:39 +0200
commite3a9e681adb779b39565a28b3252c3be1033f994 (patch)
tree1f613b0aca09f5304ee45af45ef14f28f17f7a36 /arch
parent734d099ba644f5a92c70efa3d54d0ba2500ce162 (diff)
downloadlinux-e3a9e681adb779b39565a28b3252c3be1033f994.tar.bz2
x86/entry: Fixup bad_iret vs noinstr
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 <elver@google.com> Suggested-by: Marco Elver <elver@google.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Tested-by: Marco Elver <elver@google.com> Link: https://lkml.kernel.org/r/20200618144801.760070502@infradead.org
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/kernel/traps.c6
-rw-r--r--arch/x86/lib/memcpy_64.S4
2 files changed, 7 insertions, 3 deletions
diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
index af75109485c2..a7d157090572 100644
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -690,13 +690,13 @@ struct bad_iret_stack *fixup_bad_iret(struct bad_iret_stack *s)
(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;
diff --git a/arch/x86/lib/memcpy_64.S b/arch/x86/lib/memcpy_64.S
index 56b243b14c3a..bbcc05bcefad 100644
--- 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