Re: asm-x86/msr.h for sanitized headers: clean it or punt it

On Monday 31 December 2007, Andi Kleen wrote:
can you enumerate which functions need to actually go to userspace then ?
the

rdtscl/rdtscll/rdpmc primarily

i'll just mark out the useless C funcs then

__KERNEL__ markings are a crapshoot at the moment. you must also be
jumping through hoops in order to use the header in the first place since
the vanilla one wont compile out of the box.

At least the 64bit one or older 32bit one works without hoops. Agreed that
the paravirt changes destroyed it on newer 32bit though. That's an
unfortunate regression.

i dont see how when the exported code has prototypes with "u32" types in them.
but at any rate ...
---
Use __asm__ and __volatile__ in code that is exported to userspace. Wrap
kernel functions with __KERNEL__ so they get scrubbed.

Signed-off-by: Mike Frysinger <vapier@xxxxxxxxxx>
---
diff --git a/include/asm-x86/msr.h b/include/asm-x86/msr.h
index ba4b314..ffb9319 100644
--- a/include/asm-x86/msr.h
+++ b/include/asm-x86/msr.h
@@ -193,7 +193,7 @@ static inline int wrmsr_safe_on_cpu(unsigned int cpu, u32 msr_no, u32 l, u32 h)

/* wrmsr with exception handling */
#define wrmsr_safe(msr,a,b) ({ int ret__; \
- asm volatile("2: wrmsr ; xorl %0,%0\n" \
+ __asm__ __volatile__("2: wrmsr ; xorl %0,%0\n" \
"1:\n\t" \
".section .fixup,\"ax\"\n\t" \
"3: movl %4,%0 ; jmp 1b\n\t" \
@@ -210,7 +210,7 @@ static inline int wrmsr_safe_on_cpu(unsigned int cpu, u32 msr_no, u32 l, u32 h)

#define rdmsr_safe(msr,a,b) \
({ int ret__; \
- asm volatile ("1: rdmsr\n" \
+ __asm__ __volatile__ ("1: rdmsr\n" \
"2:\n" \
".section .fixup,\"ax\"\n" \
"3: movl %4,%0\n" \
@@ -230,17 +230,17 @@ static inline int wrmsr_safe_on_cpu(unsigned int cpu, u32 msr_no, u32 l, u32 h)
__asm__ __volatile__ ("rdtsc" : "=a" (low) : : "edx")

#define rdtscp(low,high,aux) \
- asm volatile (".byte 0x0f,0x01,0xf9" : "=a" (low), "=d" (high), "=c" (aux))
+ __asm__ __volatile__ (".byte 0x0f,0x01,0xf9" : "=a" (low), "=d" (high), "=c" (aux))

#define rdtscll(val) do { \
unsigned int __a,__d; \
- asm volatile("rdtsc" : "=a" (__a), "=d" (__d)); \
+ __asm__ __volatile__("rdtsc" : "=a" (__a), "=d" (__d)); \
(val) = ((unsigned long)__a) | (((unsigned long)__d)<<32); \
} while(0)

#define rdtscpll(val, aux) do { \
unsigned long __a, __d; \
- asm volatile (".byte 0x0f,0x01,0xf9" : "=a" (__a), "=d" (__d), "=c" (aux)); \
+ __asm__ __volatile__ (".byte 0x0f,0x01,0xf9" : "=a" (__a), "=d" (__d), "=c" (aux)); \
(val) = (__d << 32) | __a; \
} while (0)

@@ -320,6 +320,7 @@ static inline unsigned int cpuid_edx(unsigned int op)
return edx;
}

+#ifdef __KERNEL__
#ifdef CONFIG_SMP
void rdmsr_on_cpu(unsigned int cpu, u32 msr_no, u32 *l, u32 *h);
void wrmsr_on_cpu(unsigned int cpu, u32 msr_no, u32 l, u32 h);
@@ -343,6 +344,7 @@ static inline int wrmsr_safe_on_cpu(unsigned int cpu, u32 msr_no, u32 l, u32 h)
return wrmsr_safe(msr_no, l, h);
}
#endif /* CONFIG_SMP */
+#endif /* __KERNEL__ */
#endif /* __ASSEMBLY__ */

#endif /* !__i386__ */
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