forked from luck/tmp_suning_uos_patched
x86: Document rdmsr_safe restrictions
Recently, I got bitten by using rdmsr_safe too early in the boot process. Document its shortcomings for future reference. Link: http://lkml.kernel.org/r/4ED5B70F.606@lwfinger.net Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
This commit is contained in:
parent
bd39906397
commit
ce37defc0f
|
@ -169,7 +169,14 @@ static inline int wrmsr_safe(unsigned msr, unsigned low, unsigned high)
|
|||
return native_write_msr_safe(msr, low, high);
|
||||
}
|
||||
|
||||
/* rdmsr with exception handling */
|
||||
/*
|
||||
* rdmsr with exception handling.
|
||||
*
|
||||
* Please note that the exception handling works only after we've
|
||||
* switched to the "smart" #GP handler in trap_init() which knows about
|
||||
* exception tables - using this macro earlier than that causes machine
|
||||
* hangs on boxes which do not implement the @msr in the first argument.
|
||||
*/
|
||||
#define rdmsr_safe(msr, p1, p2) \
|
||||
({ \
|
||||
int __err; \
|
||||
|
|
Loading…
Reference in New Issue
Block a user