![H. Peter Anvin](/assets/img/avatar_default.png)
When implementing things as macros, make sure we use typecasts and parentheses where needed. The macros as defined were vulnerable to surreptitious promotion causing problems. Avoid macros where practical; e.g. wrmsr() can be an inline instead. Signed-off-by: H. Peter Anvin <hpa@zytor.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
162 lines
3.8 KiB
C
162 lines
3.8 KiB
C
#ifndef __ASM_MSR_H
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#define __ASM_MSR_H
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#include <asm/msr-index.h>
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#ifdef __KERNEL__
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#ifndef __ASSEMBLY__
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#include <asm/errno.h>
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static inline unsigned long long native_read_msr(unsigned int msr)
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{
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unsigned long long val;
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asm volatile("rdmsr" : "=A" (val) : "c" (msr));
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return val;
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}
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static inline unsigned long long native_read_msr_safe(unsigned int msr,
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int *err)
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{
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unsigned long long val;
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asm volatile("2: rdmsr ; xorl %0,%0\n"
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"1:\n\t"
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".section .fixup,\"ax\"\n\t"
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"3: movl %3,%0 ; jmp 1b\n\t"
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".previous\n\t"
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".section __ex_table,\"a\"\n"
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" .align 4\n\t"
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" .long 2b,3b\n\t"
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".previous"
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: "=r" (*err), "=A" (val)
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: "c" (msr), "i" (-EFAULT));
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return val;
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}
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static inline void native_write_msr(unsigned int msr, unsigned long long val)
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{
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asm volatile("wrmsr" : : "c" (msr), "A"(val));
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}
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static inline int native_write_msr_safe(unsigned int msr,
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unsigned long long val)
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{
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int err;
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asm volatile("2: wrmsr ; xorl %0,%0\n"
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"1:\n\t"
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".section .fixup,\"ax\"\n\t"
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"3: movl %4,%0 ; jmp 1b\n\t"
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".previous\n\t"
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".section __ex_table,\"a\"\n"
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" .align 4\n\t"
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" .long 2b,3b\n\t"
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".previous"
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: "=a" (err)
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: "c" (msr), "0" ((u32)val), "d" ((u32)(val>>32)),
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"i" (-EFAULT));
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return err;
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}
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static inline unsigned long long native_read_tsc(void)
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{
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unsigned long long val;
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asm volatile("rdtsc" : "=A" (val));
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return val;
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}
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static inline unsigned long long native_read_pmc(void)
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{
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unsigned long long val;
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asm volatile("rdpmc" : "=A" (val));
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return val;
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}
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#ifdef CONFIG_PARAVIRT
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#include <asm/paravirt.h>
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#else
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#include <linux/errno.h>
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/*
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* Access to machine-specific registers (available on 586 and better only)
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* Note: the rd* operations modify the parameters directly (without using
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* pointer indirection), this allows gcc to optimize better
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*/
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#define rdmsr(msr,val1,val2) \
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do { \
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u64 __val = native_read_msr(msr); \
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(val1) = (u32)__val; \
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(val2) = (u32)(__val >> 32); \
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} while(0)
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static inline void wrmsr(u32 __msr, u32 __low, u32 __high)
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{
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native_write_msr(__msr, ((u64)__high << 32) | __low);
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}
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#define rdmsrl(msr,val) \
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((val) = native_read_msr(msr))
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#define wrmsrl(msr,val) native_write_msr(msr, val)
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/* wrmsr with exception handling */
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static inline int wrmsr_safe(u32 __msr, u32 __low, u32 __high)
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{
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return native_write_msr_safe(__msr, ((u64)__high << 32) | __low);
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}
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/* rdmsr with exception handling */
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#define rdmsr_safe(msr,p1,p2) \
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({ \
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int __err; \
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u64 __val = native_read_msr_safe(msr, &__err); \
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(*p1) = (u32)__val; \
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(*p2) = (u32)(__val >> 32); \
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__err; \
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})
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#define rdtscl(low) \
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((low) = (u32)native_read_tsc())
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#define rdtscll(val) \
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((val) = native_read_tsc())
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#define write_tsc(val1,val2) wrmsr(0x10, val1, val2)
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#define rdpmc(counter,low,high) \
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do { \
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u64 _l = native_read_pmc(); \
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(low) = (u32)_l; \
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(high) = (u32)(_l >> 32); \
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} while(0)
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#endif /* !CONFIG_PARAVIRT */
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#ifdef CONFIG_SMP
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void rdmsr_on_cpu(unsigned int cpu, u32 msr_no, u32 *l, u32 *h);
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void wrmsr_on_cpu(unsigned int cpu, u32 msr_no, u32 l, u32 h);
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int rdmsr_safe_on_cpu(unsigned int cpu, u32 msr_no, u32 *l, u32 *h);
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int wrmsr_safe_on_cpu(unsigned int cpu, u32 msr_no, u32 l, u32 h);
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#else /* CONFIG_SMP */
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static inline void rdmsr_on_cpu(unsigned int cpu, u32 msr_no, u32 *l, u32 *h)
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{
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rdmsr(msr_no, *l, *h);
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}
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static inline void wrmsr_on_cpu(unsigned int cpu, u32 msr_no, u32 l, u32 h)
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{
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wrmsr(msr_no, l, h);
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}
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static inline 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_safe(msr_no, l, h);
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}
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static inline 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_safe(msr_no, l, h);
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}
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#endif /* CONFIG_SMP */
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#endif
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#endif
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#endif /* __ASM_MSR_H */
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