>> +#ifdef __x86_64__ >> +extern grub_uint64_t grub_relocator32_backward_src; >> +#else >> +extern grub_uint32_t grub_relocator32_backward_src; >> +#endif > > You could make this a pointer, or grub_uintptr_t > (the latter we don't yet have, it seems like a good excuse to > add it if a pointer is not suitable :-)). grub_addr_t would actually do the job. > >> +#ifndef __x86_64__ >> + /* mov imm32, %eax */ >> + .byte 0xb8 >> +RELOCATOR_VARIABLE(dest) >> + .long 0 >> + mov %eax, %edi > > Please use size qualifiers (e.g. movl). > > Also, remember to indent the first parameter like we do elsewhere > (e.g. ".long\t0", "movl\t%eax, %edi", etc). > Ok >> + /* Backward movsl is implicitly off-by-four. compensate that. */ >> + subl $4, %esi >> + subl $4, %edi >> + >> + /* Backward copy. */ >> + std >> + addl %ecx, %esi >> + addl %ecx, %edi >> + >> + rep >> + movsl > > Are you sure moving to movsl is a good idea? Maybe the payload size is not > 4-aligned. > On AFAIK x86 movsl works on unaligned addresses too. I'll recheck >> +#ifdef APPLE_CC >> + add $(cont0 - base), %eax >> +#else >> + add $(cont0 - base), %rax >> +#endif > > What's the issue at hand? Apple assembler [1] can't add an inmediate to > %rax ? > Apple linker can't handle 64-bit differences > Truncating it seems like it could be problematic if %eax overflows. > Actually it's not a problem since this code is put together with kernel which executes in 32-bit mode so it can't be over 4GiB. If we base 64-bit relocator it will be a problem if OS wants to go over 4GiB. > [1] btw, APPLE_CC macro for assembler checks is really confusing > I'll try with __apple__ > Please use macros for such things (see GRUB_MEMORY_MACHINE_CR0_PE_ON). Will look into it > > -- > Robert Millan > > The DRM opt-in fallacy: "Your data belongs to us. We will decide when (and > how) you may access your data; but nobody's threatening your freedom: we > still allow you to remove your data and not access it at all." > > > _______________________________________________ > Grub-devel mailing list > Grub-devel@gnu.org > http://lists.gnu.org/mailman/listinfo/grub-devel >
-- Regards Vladimir 'phcoder' Serbinenko Personal git repository: http://repo.or.cz/w/grub2/phcoder.git _______________________________________________ Grub-devel mailing list Grub-devel@gnu.org http://lists.gnu.org/mailman/listinfo/grub-devel
