Messages in this thread | | | Date | Sun, 10 Nov 2002 20:22:53 +0100 | From | Pavel Machek <> | Subject | Re: swsusp critical code rewritten to assembly |
| |
Hi!
> > do_magic was really too fragile to be written in C. This patch > > rewrites it into assembly, to make sure C compiler does not generate > > stack access and corrupt memory that way. Plus it cleans up suspend.c > > a bit, makes it really free memory it needs, an no longer calls > > drivers from atomic context. > > But this still has stuff in C: > > > + asm volatile ("movl %0, %%esp" :: "m" (saved_context_esp)); > > + asm volatile ("movl %0, %%ebp" :: "m" (saved_context_ebp)); > > + asm volatile ("movl %0, %%eax" :: "m" (saved_context_eax)); > > + asm volatile ("movl %0, %%ebx" :: "m" (saved_context_ebx)); > > + asm volatile ("movl %0, %%ecx" :: "m" (saved_context_ecx)); > > + asm volatile ("movl %0, %%edx" :: "m" (saved_context_edx)); > > + asm volatile ("movl %0, %%esi" :: "m" (saved_context_esi)); > > + asm volatile ("movl %0, %%edi" :: "m" (saved_context_edi)); > > > > - fix_processor_context(); > > + restore_processor_state(); > > What's up with that? There's no way you can safely restore regular > registers and _especially_ %%esp from C code, since the compiler may be > using them for other things.
After applying that patch, this stuff is no longer used for suspend-to-disk. Its still there for suspend-to-ram; I'll fix that.
Pavel
-- Casualities in World Trade Center: ~3k dead inside the building, cryptography in U.S.A. and free speech in Czech Republic. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |