diff options
Diffstat (limited to 'arch/x86/lib')
| -rw-r--r-- | arch/x86/lib/Makefile | 1 | ||||
| -rw-r--r-- | arch/x86/lib/clear_page_64.S | 2 | ||||
| -rw-r--r-- | arch/x86/lib/cpu.c | 2 | ||||
| -rw-r--r-- | arch/x86/lib/error-inject.c | 1 | ||||
| -rw-r--r-- | arch/x86/lib/msr-smp.c | 43 | ||||
| -rw-r--r-- | arch/x86/lib/retpoline.S | 56 |
6 files changed, 30 insertions, 75 deletions
diff --git a/arch/x86/lib/Makefile b/arch/x86/lib/Makefile index 91e9700cc6dc..25a972c61b0a 100644 --- a/arch/x86/lib/Makefile +++ b/arch/x86/lib/Makefile @@ -28,7 +28,6 @@ lib-$(CONFIG_INSTRUCTION_DECODER) += insn.o inat.o insn-eval.o lib-$(CONFIG_RANDOMIZE_BASE) += kaslr.o lib-$(CONFIG_FUNCTION_ERROR_INJECTION) += error-inject.o lib-$(CONFIG_RETPOLINE) += retpoline.o -OBJECT_FILES_NON_STANDARD_retpoline.o :=y obj-y += msr.o msr-reg.o msr-reg-export.o hweight.o diff --git a/arch/x86/lib/clear_page_64.S b/arch/x86/lib/clear_page_64.S index 81b1635d67de..88acd349911b 100644 --- a/arch/x86/lib/clear_page_64.S +++ b/arch/x86/lib/clear_page_64.S @@ -1,6 +1,4 @@ #include <linux/linkage.h> -#include <asm/cpufeatures.h> -#include <asm/alternative-asm.h> #include <asm/export.h> /* diff --git a/arch/x86/lib/cpu.c b/arch/x86/lib/cpu.c index d6f848d1211d..2dd1fe13a37b 100644 --- a/arch/x86/lib/cpu.c +++ b/arch/x86/lib/cpu.c @@ -18,7 +18,7 @@ unsigned int x86_model(unsigned int sig) { unsigned int fam, model; - fam = x86_family(sig); + fam = x86_family(sig); model = (sig >> 4) & 0xf; diff --git a/arch/x86/lib/error-inject.c b/arch/x86/lib/error-inject.c index 7b881d03d0dd..3cdf06128d13 100644 --- a/arch/x86/lib/error-inject.c +++ b/arch/x86/lib/error-inject.c @@ -7,6 +7,7 @@ asmlinkage void just_return_func(void); asm( ".type just_return_func, @function\n" + ".globl just_return_func\n" "just_return_func:\n" " ret\n" ".size just_return_func, .-just_return_func\n" diff --git a/arch/x86/lib/msr-smp.c b/arch/x86/lib/msr-smp.c index 693cce0be82d..fee8b9c0520c 100644 --- a/arch/x86/lib/msr-smp.c +++ b/arch/x86/lib/msr-smp.c @@ -2,6 +2,7 @@ #include <linux/export.h> #include <linux/preempt.h> #include <linux/smp.h> +#include <linux/completion.h> #include <asm/msr.h> static void __rdmsr_on_cpu(void *info) @@ -143,13 +144,19 @@ void wrmsr_on_cpus(const struct cpumask *mask, u32 msr_no, struct msr *msrs) } EXPORT_SYMBOL(wrmsr_on_cpus); +struct msr_info_completion { + struct msr_info msr; + struct completion done; +}; + /* These "safe" variants are slower and should be used when the target MSR may not actually exist. */ static void __rdmsr_safe_on_cpu(void *info) { - struct msr_info *rv = info; + struct msr_info_completion *rv = info; - rv->err = rdmsr_safe(rv->msr_no, &rv->reg.l, &rv->reg.h); + rv->msr.err = rdmsr_safe(rv->msr.msr_no, &rv->msr.reg.l, &rv->msr.reg.h); + complete(&rv->done); } static void __wrmsr_safe_on_cpu(void *info) @@ -161,17 +168,26 @@ static void __wrmsr_safe_on_cpu(void *info) int rdmsr_safe_on_cpu(unsigned int cpu, u32 msr_no, u32 *l, u32 *h) { + struct msr_info_completion rv; + call_single_data_t csd = { + .func = __rdmsr_safe_on_cpu, + .info = &rv, + }; int err; - struct msr_info rv; memset(&rv, 0, sizeof(rv)); + init_completion(&rv.done); + rv.msr.msr_no = msr_no; - rv.msr_no = msr_no; - err = smp_call_function_single(cpu, __rdmsr_safe_on_cpu, &rv, 1); - *l = rv.reg.l; - *h = rv.reg.h; + err = smp_call_function_single_async(cpu, &csd); + if (!err) { + wait_for_completion(&rv.done); + err = rv.msr.err; + } + *l = rv.msr.reg.l; + *h = rv.msr.reg.h; - return err ? err : rv.err; + return err; } EXPORT_SYMBOL(rdmsr_safe_on_cpu); @@ -209,16 +225,13 @@ EXPORT_SYMBOL(wrmsrl_safe_on_cpu); int rdmsrl_safe_on_cpu(unsigned int cpu, u32 msr_no, u64 *q) { + u32 low, high; int err; - struct msr_info rv; - memset(&rv, 0, sizeof(rv)); + err = rdmsr_safe_on_cpu(cpu, msr_no, &low, &high); + *q = (u64)high << 32 | low; - rv.msr_no = msr_no; - err = smp_call_function_single(cpu, __rdmsr_safe_on_cpu, &rv, 1); - *q = rv.reg.q; - - return err ? err : rv.err; + return err; } EXPORT_SYMBOL(rdmsrl_safe_on_cpu); diff --git a/arch/x86/lib/retpoline.S b/arch/x86/lib/retpoline.S index 480edc3a5e03..c909961e678a 100644 --- a/arch/x86/lib/retpoline.S +++ b/arch/x86/lib/retpoline.S @@ -7,7 +7,6 @@ #include <asm/alternative-asm.h> #include <asm/export.h> #include <asm/nospec-branch.h> -#include <asm/bitsperlong.h> .macro THUNK reg .section .text.__x86.indirect_thunk @@ -47,58 +46,3 @@ GENERATE_THUNK(r13) GENERATE_THUNK(r14) GENERATE_THUNK(r15) #endif - -/* - * Fill the CPU return stack buffer. - * - * Each entry in the RSB, if used for a speculative 'ret', contains an - * infinite 'pause; lfence; jmp' loop to capture speculative execution. - * - * This is required in various cases for retpoline and IBRS-based - * mitigations for the Spectre variant 2 vulnerability. Sometimes to - * eliminate potentially bogus entries from the RSB, and sometimes - * purely to ensure that it doesn't get empty, which on some CPUs would - * allow predictions from other (unwanted!) sources to be used. - * - * Google experimented with loop-unrolling and this turned out to be - * the optimal version - two calls, each with their own speculation - * trap should their return address end up getting used, in a loop. - */ -.macro STUFF_RSB nr:req sp:req - mov $(\nr / 2), %_ASM_BX - .align 16 -771: - call 772f -773: /* speculation trap */ - pause - lfence - jmp 773b - .align 16 -772: - call 774f -775: /* speculation trap */ - pause - lfence - jmp 775b - .align 16 -774: - dec %_ASM_BX - jnz 771b - add $((BITS_PER_LONG/8) * \nr), \sp -.endm - -#define RSB_FILL_LOOPS 16 /* To avoid underflow */ - -ENTRY(__fill_rsb) - STUFF_RSB RSB_FILL_LOOPS, %_ASM_SP - ret -END(__fill_rsb) -EXPORT_SYMBOL_GPL(__fill_rsb) - -#define RSB_CLEAR_LOOPS 32 /* To forcibly overwrite all entries */ - -ENTRY(__clear_rsb) - STUFF_RSB RSB_CLEAR_LOOPS, %_ASM_SP - ret -END(__clear_rsb) -EXPORT_SYMBOL_GPL(__clear_rsb) |
