On 11/15/2010 05:04 PM, Linus Torvalds wrote: > On Mon, Nov 15, 2010 at 3:16 AM, Jakub Jelinek <ja...@redhat.com> wrote: >> >> I don't see any problems on the assembly level. i8k_smm is >> not inlined in this case and checks all 3 conditions. > > If it really is related to gcc not understanding that "*regs" has > changed due to the memory being an automatic variable, and passing in > "regs" itself as a pointer to that automatic variable together with > the "memory" clobber not being sufficient, than I think it's the lack > of inlining that will automatically hide the bug. > > (Side note: and I think this does show how much of a gcc bug it is not > to consider "memory" together with passing in a pointer to an asm to > always be a clobber). > > Because if it isn't inlined, then "regs" will be seen a a real pointer > to some external memory (the caller) rather than being optimized to > just be the auto structure on the stack. Because *mem is auto only > within the context of the caller. > > Which actually points to a possible simpler: > - remove the "+m" since it adds too much register pressure > - mark the i8k_smm() as "noinline" instead. > > Quite frankly, I'd hate to add even more crud to that inline asm (to > save/restore the registers manually). It's already not the prettiest > thing around. > > So does the attached patch work for everybody? > > Linus
Hmm, that doesn't work. [ Not sure if you read to whole thread but initial workaround was to change the asm(..) to asm volatile(..) which did work. ] Jim.
