diff options
Diffstat (limited to 'arch/x86/lib/msr-smp.c')
| -rw-r--r-- | arch/x86/lib/msr-smp.c | 216 |
1 files changed, 216 insertions, 0 deletions
diff --git a/arch/x86/lib/msr-smp.c b/arch/x86/lib/msr-smp.c new file mode 100644 index 000000000..7b6cfc2c0 --- /dev/null +++ b/arch/x86/lib/msr-smp.c @@ -0,0 +1,216 @@ +// SPDX-License-Identifier: GPL-2.0 +#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) +{ + struct msr_info *rv = info; + struct msr *reg; + + if (rv->msrs) + reg = this_cpu_ptr(rv->msrs); + else + reg = &rv->reg; + + rdmsrq(rv->msr_no, reg->q); +} + +static void __wrmsr_on_cpu(void *info) +{ + struct msr_info *rv = info; + struct msr *reg; + + if (rv->msrs) + reg = this_cpu_ptr(rv->msrs); + else + reg = &rv->reg; + + wrmsrq(rv->msr_no, reg->q); +} + +int rdmsrq_on_cpu(unsigned int cpu, u32 msr_no, u64 *q) +{ + int err; + struct msr_info rv; + + memset(&rv, 0, sizeof(rv)); + + rv.msr_no = msr_no; + err = smp_call_function_single(cpu, __rdmsr_on_cpu, &rv, 1); + *q = rv.reg.q; + + return err; +} +EXPORT_SYMBOL(rdmsrq_on_cpu); + +int wrmsrq_on_cpu(unsigned int cpu, u32 msr_no, u64 q) +{ + int err; + struct msr_info rv; + + memset(&rv, 0, sizeof(rv)); + + rv.msr_no = msr_no; + rv.reg.q = q; + + err = smp_call_function_single(cpu, __wrmsr_on_cpu, &rv, 1); + + return err; +} +EXPORT_SYMBOL(wrmsrq_on_cpu); + +static void __rwmsr_on_cpus(const struct cpumask *mask, u32 msr_no, + struct msr __percpu *msrs, + void (*msr_func) (void *info)) +{ + struct msr_info rv; + int this_cpu; + + memset(&rv, 0, sizeof(rv)); + + rv.msrs = msrs; + rv.msr_no = msr_no; + + this_cpu = get_cpu(); + + if (cpumask_test_cpu(this_cpu, mask)) + msr_func(&rv); + + smp_call_function_many(mask, msr_func, &rv, 1); + put_cpu(); +} + +/* rdmsr on a bunch of CPUs + * + * @mask: which CPUs + * @msr_no: which MSR + * @msrs: array of MSR values + * + */ +void rdmsr_on_cpus(const struct cpumask *mask, u32 msr_no, struct msr __percpu *msrs) +{ + __rwmsr_on_cpus(mask, msr_no, msrs, __rdmsr_on_cpu); +} +EXPORT_SYMBOL(rdmsr_on_cpus); + +/* + * wrmsr on a bunch of CPUs + * + * @mask: which CPUs + * @msr_no: which MSR + * @msrs: array of MSR values + * + */ +void wrmsr_on_cpus(const struct cpumask *mask, u32 msr_no, struct msr __percpu *msrs) +{ + __rwmsr_on_cpus(mask, msr_no, msrs, __wrmsr_on_cpu); +} +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_completion *rv = info; + + rv->msr.err = rdmsrq_safe(rv->msr.msr_no, &rv->msr.reg.q); + complete(&rv->done); +} + +static void __wrmsr_safe_on_cpu(void *info) +{ + struct msr_info *rv = info; + + rv->err = wrmsrq_safe(rv->msr_no, rv->reg.q); +} + +int wrmsrq_safe_on_cpu(unsigned int cpu, u32 msr_no, u64 q) +{ + int err; + struct msr_info rv; + + memset(&rv, 0, sizeof(rv)); + + rv.msr_no = msr_no; + rv.reg.q = q; + + err = smp_call_function_single(cpu, __wrmsr_safe_on_cpu, &rv, 1); + + return err ? err : rv.err; +} +EXPORT_SYMBOL(wrmsrq_safe_on_cpu); + +int rdmsrq_safe_on_cpu(unsigned int cpu, u32 msr_no, u64 *q) +{ + struct msr_info_completion rv; + call_single_data_t csd; + int err; + + INIT_CSD(&csd, __rdmsr_safe_on_cpu, &rv); + + memset(&rv, 0, sizeof(rv)); + init_completion(&rv.done); + rv.msr.msr_no = msr_no; + + err = smp_call_function_single_async(cpu, &csd); + if (!err) { + wait_for_completion(&rv.done); + err = rv.msr.err; + } + *q = rv.msr.reg.q; + + return err; +} +EXPORT_SYMBOL(rdmsrq_safe_on_cpu); + +/* + * These variants are significantly slower, but allows control over + * the entire 32-bit GPR set. + */ +static void __rdmsr_safe_regs_on_cpu(void *info) +{ + struct msr_regs_info *rv = info; + + rv->err = rdmsr_safe_regs(rv->regs); +} + +static void __wrmsr_safe_regs_on_cpu(void *info) +{ + struct msr_regs_info *rv = info; + + rv->err = wrmsr_safe_regs(rv->regs); +} + +int rdmsr_safe_regs_on_cpu(unsigned int cpu, u32 regs[8]) +{ + int err; + struct msr_regs_info rv; + + rv.regs = regs; + rv.err = -EIO; + err = smp_call_function_single(cpu, __rdmsr_safe_regs_on_cpu, &rv, 1); + + return err ? err : rv.err; +} +EXPORT_SYMBOL(rdmsr_safe_regs_on_cpu); + +int wrmsr_safe_regs_on_cpu(unsigned int cpu, u32 regs[8]) +{ + int err; + struct msr_regs_info rv; + + rv.regs = regs; + rv.err = -EIO; + err = smp_call_function_single(cpu, __wrmsr_safe_regs_on_cpu, &rv, 1); + + return err ? err : rv.err; +} +EXPORT_SYMBOL(wrmsr_safe_regs_on_cpu); |