Messages in this thread | | | From | Mike Frysinger <> | Subject | Re: [patch] use __asm__ and __volatile__ in asm-x86_64/msr.h | Date | Mon, 18 Jun 2007 10:02:21 -0400 |
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On Monday 18 June 2007, H. Peter Anvin wrote: > Mike Frysinger wrote: > > Most of the macros in msr.h already use __asm__ and __volatile__, this > > patch brings the rest into line. This is needed since these get exported > > into userspace (need to use strict __asm__ vs asm when gcc compiles with > > GNU extensions turned off). > > --- > > diff --git a/include/asm-x86_64/msr.h b/include/asm-x86_64/msr.h > > index d5c55b8..ed15d2b 100644 > > --- a/include/asm-x86_64/msr.h > > +++ b/include/asm-x86_64/msr.h > > @@ -33,7 +33,7 @@ > > > > /* 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" \ > > @@ -50,7 +50,7 @@ > > > > #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" \ > > NAK. > > This is wrong for two reasons: > > - MSRs are not accessible in user space. > - .section .fixup is not applicable to user space. > > Anything MSR-related should be protected by __KERNEL__ instead. > > This NAK doesn't apply to rdtsc* and rdpmc* changes, however, as those > instructions are legitimate in userspace.
then someone needs to audit msr.h for this because currently it lacks __KERNEL__ of any kind yet is exported completely to userspace ... i dont know anything about this instructions so that someone != me
this is similar to what i heard last time i tried to fixup msr.h for userspace, but the file still hasnt been updated ... -mike [unhandled content-type:application/pgp-signature] | |