Messages in this thread | | | From | Andy Lutomirski <> | Date | Wed, 15 Jun 2016 11:44:48 -0700 | Subject | Re: [x86] 5ac0c41bf3: WARNING: CPU: 0 PID: 0 at arch/x86/mm/extable.c:50 ex_handler_rdmsr_unsafe |
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On Wed, Jun 15, 2016 at 11:23 AM, Borislav Petkov <bp@alien8.de> wrote: > On Wed, Jun 15, 2016 at 11:12:37AM -0700, Andy Lutomirski wrote: >> I want to see actual_problem in the log. > > So the optimal thing to do for that is to return an error to the calling > site which says "exception got handled" and then the *calling* site can > dump_stack(). > > And the old code did that: > > static inline unsigned long long native_read_msr_safe(unsigned int msr, > int *err) > { > DECLARE_ARGS(val, low, high); > > asm volatile("2: rdmsr ; xor %[err],%[err]\n" > "1:\n\t" > ".section .fixup,\"ax\"\n\t" > "3: mov %[fault],%[err] ; jmp 1b\n\t" > ".previous\n\t" > _ASM_EXTABLE(2b, 3b) > : [err] "=r" (*err), EAX_EDX_RET(val, low, high) > : "c" (msr), [fault] "i" (-EIO)); > ^^^^ >
Then we end up with bloat. The current thing generates very compact code.
--Andy
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