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https://github.com/edk2-porting/linux-next.git
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c6f31932d0
Propagate error (-ENXIO) from smp_call_function_single(). These errors can happen when a CPU is unplugged while the MSR driver is open. Signed-off-by: H. Peter Anvin <hpa@zytor.com>
104 lines
2.0 KiB
C
104 lines
2.0 KiB
C
#include <linux/module.h>
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#include <linux/preempt.h>
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#include <linux/smp.h>
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#include <asm/msr.h>
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struct msr_info {
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u32 msr_no;
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u32 l, h;
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int err;
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};
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static void __rdmsr_on_cpu(void *info)
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{
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struct msr_info *rv = info;
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rdmsr(rv->msr_no, rv->l, rv->h);
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}
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static void __rdmsr_safe_on_cpu(void *info)
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{
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struct msr_info *rv = info;
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rv->err = rdmsr_safe(rv->msr_no, &rv->l, &rv->h);
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}
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static int _rdmsr_on_cpu(unsigned int cpu, u32 msr_no, u32 *l, u32 *h, int safe)
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{
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int err = 0;
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struct msr_info rv;
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rv.msr_no = msr_no;
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if (safe) {
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err = smp_call_function_single(cpu, __rdmsr_safe_on_cpu,
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&rv, 1);
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err = err ? err : rv.err;
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} else {
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err = smp_call_function_single(cpu, __rdmsr_on_cpu, &rv, 1);
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}
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*l = rv.l;
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*h = rv.h;
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return err;
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}
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static void __wrmsr_on_cpu(void *info)
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{
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struct msr_info *rv = info;
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wrmsr(rv->msr_no, rv->l, rv->h);
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}
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static void __wrmsr_safe_on_cpu(void *info)
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{
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struct msr_info *rv = info;
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rv->err = wrmsr_safe(rv->msr_no, rv->l, rv->h);
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}
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static int _wrmsr_on_cpu(unsigned int cpu, u32 msr_no, u32 l, u32 h, int safe)
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{
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int err = 0;
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struct msr_info rv;
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rv.msr_no = msr_no;
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rv.l = l;
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rv.h = h;
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if (safe) {
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err = smp_call_function_single(cpu, __wrmsr_safe_on_cpu,
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&rv, 1);
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err = err ? err : rv.err;
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} else {
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err = smp_call_function_single(cpu, __wrmsr_on_cpu, &rv, 1);
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}
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return err;
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}
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int wrmsr_on_cpu(unsigned int cpu, u32 msr_no, u32 l, u32 h)
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{
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return _wrmsr_on_cpu(cpu, msr_no, l, h, 0);
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}
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int rdmsr_on_cpu(unsigned int cpu, u32 msr_no, u32 *l, u32 *h)
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{
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return _rdmsr_on_cpu(cpu, msr_no, l, h, 0);
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}
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/* These "safe" variants are slower and should be used when the target MSR
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may not actually exist. */
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int wrmsr_safe_on_cpu(unsigned int cpu, u32 msr_no, u32 l, u32 h)
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{
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return _wrmsr_on_cpu(cpu, msr_no, l, h, 1);
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}
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int rdmsr_safe_on_cpu(unsigned int cpu, u32 msr_no, u32 *l, u32 *h)
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{
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return _rdmsr_on_cpu(cpu, msr_no, l, h, 1);
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}
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EXPORT_SYMBOL(rdmsr_on_cpu);
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EXPORT_SYMBOL(wrmsr_on_cpu);
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EXPORT_SYMBOL(rdmsr_safe_on_cpu);
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EXPORT_SYMBOL(wrmsr_safe_on_cpu);
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