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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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4e9baad8f5
Add safe (exception handled) variants of rdmsr_on_cpu and wrmsr_on_cpu. You should use these when the target MSR may not actually exist, as doing so could trigger an exception which the regular functions do not handle. The safe variants are slower, though. The upcoming coretemp hardware monitoring driver will need this. Signed-off-by: Rudolf Marek <r.marek@assembler.cz> Cc: Alexey Dobriyan <adobriyan@openvz.org> Cc: Dave Jones <davej@redhat.com> Signed-off-by: Jean Delvare <khali@linux-fr.org>
120 lines
2.3 KiB
C
120 lines
2.3 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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preempt_disable();
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if (smp_processor_id() == cpu)
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if (safe)
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err = rdmsr_safe(msr_no, l, h);
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else
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rdmsr(msr_no, *l, *h);
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else {
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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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smp_call_function_single(cpu, __rdmsr_safe_on_cpu,
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&rv, 0, 1);
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err = rv.err;
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} else {
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smp_call_function_single(cpu, __rdmsr_on_cpu, &rv, 0, 1);
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}
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*l = rv.l;
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*h = rv.h;
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}
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preempt_enable();
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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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preempt_disable();
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if (smp_processor_id() == cpu)
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if (safe)
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err = wrmsr_safe(msr_no, l, h);
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else
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wrmsr(msr_no, l, h);
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else {
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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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smp_call_function_single(cpu, __wrmsr_safe_on_cpu,
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&rv, 0, 1);
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err = rv.err;
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} else {
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smp_call_function_single(cpu, __wrmsr_on_cpu, &rv, 0, 1);
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}
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}
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preempt_enable();
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return err;
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}
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void wrmsr_on_cpu(unsigned int cpu, u32 msr_no, u32 l, u32 h)
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{
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_wrmsr_on_cpu(cpu, msr_no, l, h, 0);
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}
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void rdmsr_on_cpu(unsigned int cpu, u32 msr_no, u32 *l, u32 *h)
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{
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_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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