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-rw-r--r--arch/x86/lib/msr-smp.c279
1 files changed, 279 insertions, 0 deletions
diff --git a/arch/x86/lib/msr-smp.c b/arch/x86/lib/msr-smp.c
new file mode 100644
index 0000000000..40bbe56bde
--- /dev/null
+++ b/arch/x86/lib/msr-smp.c
@@ -0,0 +1,279 @@
+// 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;
+ int this_cpu = raw_smp_processor_id();
+
+ if (rv->msrs)
+ reg = per_cpu_ptr(rv->msrs, this_cpu);
+ else
+ reg = &rv->reg;
+
+ rdmsr(rv->msr_no, reg->l, reg->h);
+}
+
+static void __wrmsr_on_cpu(void *info)
+{
+ struct msr_info *rv = info;
+ struct msr *reg;
+ int this_cpu = raw_smp_processor_id();
+
+ if (rv->msrs)
+ reg = per_cpu_ptr(rv->msrs, this_cpu);
+ else
+ reg = &rv->reg;
+
+ wrmsr(rv->msr_no, reg->l, reg->h);
+}
+
+int rdmsr_on_cpu(unsigned int cpu, u32 msr_no, u32 *l, u32 *h)
+{
+ 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);
+ *l = rv.reg.l;
+ *h = rv.reg.h;
+
+ return err;
+}
+EXPORT_SYMBOL(rdmsr_on_cpu);
+
+int rdmsrl_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(rdmsrl_on_cpu);
+
+int wrmsr_on_cpu(unsigned int cpu, u32 msr_no, u32 l, u32 h)
+{
+ int err;
+ struct msr_info rv;
+
+ memset(&rv, 0, sizeof(rv));
+
+ rv.msr_no = msr_no;
+ rv.reg.l = l;
+ rv.reg.h = h;
+ err = smp_call_function_single(cpu, __wrmsr_on_cpu, &rv, 1);
+
+ return err;
+}
+EXPORT_SYMBOL(wrmsr_on_cpu);
+
+int wrmsrl_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(wrmsrl_on_cpu);
+
+static void __rwmsr_on_cpus(const struct cpumask *mask, u32 msr_no,
+ struct msr *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 *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 *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 = 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)
+{
+ struct msr_info *rv = info;
+
+ rv->err = wrmsr_safe(rv->msr_no, rv->reg.l, rv->reg.h);
+}
+
+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;
+ 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;
+ }
+ *l = rv.msr.reg.l;
+ *h = rv.msr.reg.h;
+
+ return err;
+}
+EXPORT_SYMBOL(rdmsr_safe_on_cpu);
+
+int wrmsr_safe_on_cpu(unsigned int cpu, u32 msr_no, u32 l, u32 h)
+{
+ int err;
+ struct msr_info rv;
+
+ memset(&rv, 0, sizeof(rv));
+
+ rv.msr_no = msr_no;
+ rv.reg.l = l;
+ rv.reg.h = h;
+ err = smp_call_function_single(cpu, __wrmsr_safe_on_cpu, &rv, 1);
+
+ return err ? err : rv.err;
+}
+EXPORT_SYMBOL(wrmsr_safe_on_cpu);
+
+int wrmsrl_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(wrmsrl_safe_on_cpu);
+
+int rdmsrl_safe_on_cpu(unsigned int cpu, u32 msr_no, u64 *q)
+{
+ u32 low, high;
+ int err;
+
+ err = rdmsr_safe_on_cpu(cpu, msr_no, &low, &high);
+ *q = (u64)high << 32 | low;
+
+ return err;
+}
+EXPORT_SYMBOL(rdmsrl_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);