722a0d22d0
Due to a typo the msr accessor function introduced in22085a66c2didn't have any lasting effects because they accidentally wrote the old value back. Afterc0a639ad0bthis at the very least this causes cpuid limits not to be lifted on some cpus leading to missing capabilities for those. Signed-off-by: Andres Freund <andres@anarazel.de> Link: http://lkml.kernel.org/r/1399598957-7011-2-git-send-email-andres@anarazel.de Cc: Borislav Petkov <bp@suse.de> Signed-off-by: H. Peter Anvin <hpa@zytor.com>
110 lines
1.6 KiB
C
110 lines
1.6 KiB
C
#include <linux/module.h>
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#include <linux/preempt.h>
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#include <asm/msr.h>
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struct msr *msrs_alloc(void)
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{
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struct msr *msrs = NULL;
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msrs = alloc_percpu(struct msr);
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if (!msrs) {
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pr_warn("%s: error allocating msrs\n", __func__);
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return NULL;
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}
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return msrs;
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}
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EXPORT_SYMBOL(msrs_alloc);
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void msrs_free(struct msr *msrs)
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{
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free_percpu(msrs);
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}
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EXPORT_SYMBOL(msrs_free);
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/**
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* Read an MSR with error handling
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*
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* @msr: MSR to read
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* @m: value to read into
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*
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* It returns read data only on success, otherwise it doesn't change the output
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* argument @m.
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*
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*/
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int msr_read(u32 msr, struct msr *m)
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{
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int err;
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u64 val;
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err = rdmsrl_safe(msr, &val);
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if (!err)
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m->q = val;
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return err;
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}
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/**
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* Write an MSR with error handling
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*
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* @msr: MSR to write
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* @m: value to write
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*/
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int msr_write(u32 msr, struct msr *m)
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{
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return wrmsrl_safe(msr, m->q);
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}
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static inline int __flip_bit(u32 msr, u8 bit, bool set)
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{
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struct msr m, m1;
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int err = -EINVAL;
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if (bit > 63)
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return err;
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err = msr_read(msr, &m);
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if (err)
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return err;
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m1 = m;
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if (set)
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m1.q |= BIT_64(bit);
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else
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m1.q &= ~BIT_64(bit);
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if (m1.q == m.q)
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return 0;
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err = msr_write(msr, &m1);
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if (err)
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return err;
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return 1;
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}
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/**
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* Set @bit in a MSR @msr.
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*
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* Retval:
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* < 0: An error was encountered.
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* = 0: Bit was already set.
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* > 0: Hardware accepted the MSR write.
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*/
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int msr_set_bit(u32 msr, u8 bit)
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{
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return __flip_bit(msr, bit, true);
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}
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/**
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* Clear @bit in a MSR @msr.
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*
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* Retval:
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* < 0: An error was encountered.
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* = 0: Bit was already cleared.
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* > 0: Hardware accepted the MSR write.
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*/
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int msr_clear_bit(u32 msr, u8 bit)
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{
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return __flip_bit(msr, bit, false);
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}
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