diff options
Diffstat (limited to 'arch/x86')
| -rw-r--r-- | arch/x86/Kconfig | 1 | ||||
| -rw-r--r-- | arch/x86/include/asm/preempt.h | 48 | ||||
| -rw-r--r-- | arch/x86/include/asm/static_call.h | 7 | ||||
| -rw-r--r-- | arch/x86/kernel/static_call.c | 17 | ||||
| -rw-r--r-- | arch/x86/kvm/x86.c | 1 |
5 files changed, 63 insertions, 11 deletions
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 7b934a591df2..595193bc2d31 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -224,6 +224,7 @@ config X86 select HAVE_STACK_VALIDATION if X86_64 select HAVE_STATIC_CALL select HAVE_STATIC_CALL_INLINE if HAVE_STACK_VALIDATION + select HAVE_PREEMPT_DYNAMIC select HAVE_RSEQ select HAVE_SYSCALL_TRACEPOINTS select HAVE_UNSTABLE_SCHED_CLOCK diff --git a/arch/x86/include/asm/preempt.h b/arch/x86/include/asm/preempt.h index 69485ca13665..f8cb8af4de5c 100644 --- a/arch/x86/include/asm/preempt.h +++ b/arch/x86/include/asm/preempt.h @@ -5,6 +5,7 @@ #include <asm/rmwcc.h> #include <asm/percpu.h> #include <linux/thread_info.h> +#include <linux/static_call_types.h> DECLARE_PER_CPU(int, __preempt_count); @@ -103,16 +104,45 @@ static __always_inline bool should_resched(int preempt_offset) } #ifdef CONFIG_PREEMPTION - extern asmlinkage void preempt_schedule_thunk(void); -# define __preempt_schedule() \ - asm volatile ("call preempt_schedule_thunk" : ASM_CALL_CONSTRAINT) - extern asmlinkage void preempt_schedule(void); - extern asmlinkage void preempt_schedule_notrace_thunk(void); -# define __preempt_schedule_notrace() \ - asm volatile ("call preempt_schedule_notrace_thunk" : ASM_CALL_CONSTRAINT) +extern asmlinkage void preempt_schedule(void); +extern asmlinkage void preempt_schedule_thunk(void); - extern asmlinkage void preempt_schedule_notrace(void); -#endif +#define __preempt_schedule_func preempt_schedule_thunk + +extern asmlinkage void preempt_schedule_notrace(void); +extern asmlinkage void preempt_schedule_notrace_thunk(void); + +#define __preempt_schedule_notrace_func preempt_schedule_notrace_thunk + +#ifdef CONFIG_PREEMPT_DYNAMIC + +DECLARE_STATIC_CALL(preempt_schedule, __preempt_schedule_func); + +#define __preempt_schedule() \ +do { \ + __STATIC_CALL_MOD_ADDRESSABLE(preempt_schedule); \ + asm volatile ("call " STATIC_CALL_TRAMP_STR(preempt_schedule) : ASM_CALL_CONSTRAINT); \ +} while (0) + +DECLARE_STATIC_CALL(preempt_schedule_notrace, __preempt_schedule_notrace_func); + +#define __preempt_schedule_notrace() \ +do { \ + __STATIC_CALL_MOD_ADDRESSABLE(preempt_schedule_notrace); \ + asm volatile ("call " STATIC_CALL_TRAMP_STR(preempt_schedule_notrace) : ASM_CALL_CONSTRAINT); \ +} while (0) + +#else /* PREEMPT_DYNAMIC */ + +#define __preempt_schedule() \ + asm volatile ("call preempt_schedule_thunk" : ASM_CALL_CONSTRAINT); + +#define __preempt_schedule_notrace() \ + asm volatile ("call preempt_schedule_notrace_thunk" : ASM_CALL_CONSTRAINT); + +#endif /* PREEMPT_DYNAMIC */ + +#endif /* PREEMPTION */ #endif /* __ASM_PREEMPT_H */ diff --git a/arch/x86/include/asm/static_call.h b/arch/x86/include/asm/static_call.h index c37f11999d0c..cbb67b6030f9 100644 --- a/arch/x86/include/asm/static_call.h +++ b/arch/x86/include/asm/static_call.h @@ -37,4 +37,11 @@ #define ARCH_DEFINE_STATIC_CALL_NULL_TRAMP(name) \ __ARCH_DEFINE_STATIC_CALL_TRAMP(name, "ret; nop; nop; nop; nop") + +#define ARCH_ADD_TRAMP_KEY(name) \ + asm(".pushsection .static_call_tramp_key, \"a\" \n" \ + ".long " STATIC_CALL_TRAMP_STR(name) " - . \n" \ + ".long " STATIC_CALL_KEY_STR(name) " - . \n" \ + ".popsection \n") + #endif /* _ASM_STATIC_CALL_H */ diff --git a/arch/x86/kernel/static_call.c b/arch/x86/kernel/static_call.c index ca9a380d9c0b..9442c4136c38 100644 --- a/arch/x86/kernel/static_call.c +++ b/arch/x86/kernel/static_call.c @@ -11,14 +11,26 @@ enum insn_type { RET = 3, /* tramp / site cond-tail-call */ }; +/* + * data16 data16 xorq %rax, %rax - a single 5 byte instruction that clears %rax + * The REX.W cancels the effect of any data16. + */ +static const u8 xor5rax[] = { 0x66, 0x66, 0x48, 0x31, 0xc0 }; + static void __ref __static_call_transform(void *insn, enum insn_type type, void *func) { + const void *emulate = NULL; int size = CALL_INSN_SIZE; const void *code; switch (type) { case CALL: code = text_gen_insn(CALL_INSN_OPCODE, insn, func); + if (func == &__static_call_return0) { + emulate = code; + code = &xor5rax; + } + break; case NOP: @@ -41,7 +53,7 @@ static void __ref __static_call_transform(void *insn, enum insn_type type, void if (unlikely(system_state == SYSTEM_BOOTING)) return text_poke_early(insn, code, size); - text_poke_bp(insn, code, size, NULL); + text_poke_bp(insn, code, size, emulate); } static void __static_call_validate(void *insn, bool tail) @@ -54,7 +66,8 @@ static void __static_call_validate(void *insn, bool tail) return; } else { if (opcode == CALL_INSN_OPCODE || - !memcmp(insn, ideal_nops[NOP_ATOMIC5], 5)) + !memcmp(insn, ideal_nops[NOP_ATOMIC5], 5) || + !memcmp(insn, xor5rax, 5)) return; } diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 1b404e4d7dd8..b967c1c774a1 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -1782,6 +1782,7 @@ EXPORT_SYMBOL_GPL(kvm_emulate_wrmsr); bool kvm_vcpu_exit_request(struct kvm_vcpu *vcpu) { + xfer_to_guest_mode_prepare(); return vcpu->mode == EXITING_GUEST_MODE || kvm_request_pending(vcpu) || xfer_to_guest_mode_work_pending(); } |