From: Peter Zijlstra <peterz@xxxxxxxxxxxxx> commit b17c2baa305cccbd16bafa289fd743cc2db77966 upstream. Replace all ret/retq instructions with ASM_RET in preparation of making it more than a single instruction. Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx> Signed-off-by: Borislav Petkov <bp@xxxxxxx> Link: https://lore.kernel.org/r/20211204134907.964635458@xxxxxxxxxxxxx Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> [bwh: Backported to 5.10: adjust context] Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- arch/x86/include/asm/linkage.h | 4 ++++ arch/x86/include/asm/paravirt.h | 2 +- arch/x86/include/asm/qspinlock_paravirt.h | 4 ++-- arch/x86/kernel/alternative.c | 2 +- arch/x86/kernel/kprobes/core.c | 2 +- arch/x86/kernel/paravirt.c | 2 +- arch/x86/kvm/emulate.c | 4 ++-- arch/x86/lib/error-inject.c | 3 ++- samples/ftrace/ftrace-direct-modify.c | 4 ++-- samples/ftrace/ftrace-direct-too.c | 2 +- samples/ftrace/ftrace-direct.c | 2 +- 11 files changed, 18 insertions(+), 13 deletions(-) --- a/arch/x86/include/asm/linkage.h +++ b/arch/x86/include/asm/linkage.h @@ -18,6 +18,10 @@ #define __ALIGN_STR __stringify(__ALIGN) #endif +#else /* __ASSEMBLY__ */ + +#define ASM_RET "ret\n\t" + #endif /* __ASSEMBLY__ */ #endif /* _ASM_X86_LINKAGE_H */ --- a/arch/x86/include/asm/paravirt.h +++ b/arch/x86/include/asm/paravirt.h @@ -630,7 +630,7 @@ bool __raw_callee_save___native_vcpu_is_ "call " #func ";" \ PV_RESTORE_ALL_CALLER_REGS \ FRAME_END \ - "ret;" \ + ASM_RET \ ".size " PV_THUNK_NAME(func) ", .-" PV_THUNK_NAME(func) ";" \ ".popsection") --- a/arch/x86/include/asm/qspinlock_paravirt.h +++ b/arch/x86/include/asm/qspinlock_paravirt.h @@ -48,7 +48,7 @@ asm (".pushsection .text;" "jne .slowpath;" "pop %rdx;" FRAME_END - "ret;" + ASM_RET ".slowpath: " "push %rsi;" "movzbl %al,%esi;" @@ -56,7 +56,7 @@ asm (".pushsection .text;" "pop %rsi;" "pop %rdx;" FRAME_END - "ret;" + ASM_RET ".size " PV_UNLOCK ", .-" PV_UNLOCK ";" ".popsection"); --- a/arch/x86/kernel/alternative.c +++ b/arch/x86/kernel/alternative.c @@ -869,7 +869,7 @@ asm ( " .type int3_magic, @function\n" "int3_magic:\n" " movl $1, (%" _ASM_ARG1 ")\n" -" ret\n" + ASM_RET " .size int3_magic, .-int3_magic\n" " .popsection\n" ); --- a/arch/x86/kernel/kprobes/core.c +++ b/arch/x86/kernel/kprobes/core.c @@ -768,7 +768,7 @@ asm( RESTORE_REGS_STRING " popfl\n" #endif - " ret\n" + ASM_RET ".size kretprobe_trampoline, .-kretprobe_trampoline\n" ); NOKPROBE_SYMBOL(kretprobe_trampoline); --- a/arch/x86/kernel/paravirt.c +++ b/arch/x86/kernel/paravirt.c @@ -40,7 +40,7 @@ extern void _paravirt_nop(void); asm (".pushsection .entry.text, \"ax\"\n" ".global _paravirt_nop\n" "_paravirt_nop:\n\t" - "ret\n\t" + ASM_RET ".size _paravirt_nop, . - _paravirt_nop\n\t" ".type _paravirt_nop, @function\n\t" ".popsection"); --- a/arch/x86/kvm/emulate.c +++ b/arch/x86/kvm/emulate.c @@ -316,7 +316,7 @@ static int fastop(struct x86_emulate_ctx __FOP_FUNC(#name) #define __FOP_RET(name) \ - "ret \n\t" \ + ASM_RET \ ".size " name ", .-" name "\n\t" #define FOP_RET(name) \ @@ -437,7 +437,7 @@ static int fastop(struct x86_emulate_ctx asm(".pushsection .fixup, \"ax\"\n" ".global kvm_fastop_exception \n" - "kvm_fastop_exception: xor %esi, %esi; ret\n" + "kvm_fastop_exception: xor %esi, %esi; " ASM_RET ".popsection"); FOP_START(setcc) --- a/arch/x86/lib/error-inject.c +++ b/arch/x86/lib/error-inject.c @@ -1,5 +1,6 @@ // SPDX-License-Identifier: GPL-2.0 +#include <linux/linkage.h> #include <linux/error-injection.h> #include <linux/kprobes.h> @@ -10,7 +11,7 @@ asm( ".type just_return_func, @function\n" ".globl just_return_func\n" "just_return_func:\n" - " ret\n" + ASM_RET ".size just_return_func, .-just_return_func\n" ); --- a/samples/ftrace/ftrace-direct-modify.c +++ b/samples/ftrace/ftrace-direct-modify.c @@ -31,7 +31,7 @@ asm ( " call my_direct_func1\n" " leave\n" " .size my_tramp1, .-my_tramp1\n" -" ret\n" + ASM_RET " .type my_tramp2, @function\n" " .globl my_tramp2\n" " my_tramp2:" @@ -39,7 +39,7 @@ asm ( " movq %rsp, %rbp\n" " call my_direct_func2\n" " leave\n" -" ret\n" + ASM_RET " .size my_tramp2, .-my_tramp2\n" " .popsection\n" ); --- a/samples/ftrace/ftrace-direct-too.c +++ b/samples/ftrace/ftrace-direct-too.c @@ -31,7 +31,7 @@ asm ( " popq %rsi\n" " popq %rdi\n" " leave\n" -" ret\n" + ASM_RET " .size my_tramp, .-my_tramp\n" " .popsection\n" ); --- a/samples/ftrace/ftrace-direct.c +++ b/samples/ftrace/ftrace-direct.c @@ -24,7 +24,7 @@ asm ( " call my_direct_func\n" " popq %rdi\n" " leave\n" -" ret\n" + ASM_RET " .size my_tramp, .-my_tramp\n" " .popsection\n" );
