[PATCH v3 13/39] x86/ibt,paravirt: Sprinkle ENDBR

Peter Zijlstra
2022-03-03T11:30:55Z

Reviewed-by: Kees Cook <keescook@chromium.org>
---
arch/x86/include/asm/paravirt.h | 1 +
arch/x86/include/asm/qspinlock_paravirt.h | 3 +++
arch/x86/kernel/kvm.c | 3 ++-
arch/x86/kernel/paravirt.c | 2 ++
4 files changed, 8 insertions(+), 1 deletion(-)

--- a/arch/x86/include/asm/paravirt.h
+++ b/arch/x86/include/asm/paravirt.h
@@ -666,6 +666,7 @@ bool __raw_callee_save___native_vcpu_is_
".globl " PV_THUNK_NAME(func) ";" \
".type " PV_THUNK_NAME(func) ", @function;" \
PV_THUNK_NAME(func) ":" \
+ ASM_ENDBR \
FRAME_BEGIN \
PV_SAVE_ALL_CALLER_REGS \
"call " #func ";" \
--- a/arch/x86/include/asm/qspinlock_paravirt.h
+++ b/arch/x86/include/asm/qspinlock_paravirt.h
@@ -2,6 +2,8 @@
#ifndef __ASM_QSPINLOCK_PARAVIRT_H
#define __ASM_QSPINLOCK_PARAVIRT_H

+#include <asm/ibt.h>
+
/*
* For x86-64, PV_CALLEE_SAVE_REGS_THUNK() saves and restores 8 64-bit
* registers. For i386, however, only 1 32-bit register needs to be saved
@@ -39,6 +41,7 @@ asm (".pushsection .text;"
".type " PV_UNLOCK ", @function;"
".align 4,0x90;"
PV_UNLOCK ": "
+ ASM_ENDBR
FRAME_BEGIN
"push %rdx;"
"mov $0x1,%eax;"
--- a/arch/x86/kernel/kvm.c
+++ b/arch/x86/kernel/kvm.c
@@ -1024,10 +1024,11 @@ asm(
".global __raw_callee_save___kvm_vcpu_is_preempted;"
".type __raw_callee_save___kvm_vcpu_is_preempted, @function;"
"__raw_callee_save___kvm_vcpu_is_preempted:"
+ASM_ENDBR
"movq __per_cpu_offset(,%rdi,8), %rax;"
"cmpb $0, " __stringify(KVM_STEAL_TIME_preempted) "+steal_time(%rax);"
"setne %al;"
-"ret;"
+ASM_RET
".size __raw_callee_save___kvm_vcpu_is_preempted, .-__raw_callee_save___kvm_vcpu_is_preempted;"
".popsection");

--- a/arch/x86/kernel/paravirt.c
+++ b/arch/x86/kernel/paravirt.c
@@ -41,6 +41,7 @@ extern void _paravirt_nop(void);
asm (".pushsection .entry.text, \"ax\"\n"
".global _paravirt_nop\n"
"_paravirt_nop:\n\t"
+ ASM_ENDBR
ASM_RET
".size _paravirt_nop, . - _paravirt_nop\n\t"
".type _paravirt_nop, @function\n\t"
@@ -50,6 +51,7 @@ asm (".pushsection .entry.text, \"ax\"\n
asm (".pushsection .entry.text, \"ax\"\n"
".global paravirt_ret0\n"
"paravirt_ret0:\n\t"
+ ASM_ENDBR
"xor %" _ASM_AX ", %" _ASM_AX ";\n\t"
ASM_RET
".size paravirt_ret0, . - paravirt_ret0\n\t"