On Tue, 17 Dec, at 12:36:37AM, Borislav Petkov wrote: > From: Borislav Petkov <bp@xxxxxxx> > > Currently, running SetVirtualAddressMap() and passing the physical > address of the virtual map array was working only by a lucky coincidence > because the memory was present in the EFI page table too. Until Toshi > went and booted this on a big HP box - the krealloc() manner of resizing > the memmap we're doing did allocate from such physical addresses which > were not mapped anymore and boom: > > http://lkml.kernel.org/r/1386806463.1791.295.camel@xxxxxxxxxxxxxxxx > > One way to take care of that issue is to reimplement the krealloc thing > but with pages. We start with contiguous pages of order 1, i.e. 2 pages, > and when we deplete that memory (shouldn't happen all that often but you > know firmware) we realloc the next power-of-two pages. > > Having the pages, it is much more handy and easy to map them into the > EFI page table with the already existing mapping code which we're using > for building the virtual mappings. > > And, it doesn't matter all that much how much pages we've used as we're > freeing them right after they've fulfilled their purpose at the end of > the function anyway. > > Reported-by: Toshi Kani <toshi.kani@xxxxxx> > Signed-off-by: Borislav Petkov <bp@xxxxxxx> > --- > arch/x86/platform/efi/efi.c | 57 ++++++++++++++++++++++++++++++++++++++------- > 1 file changed, 48 insertions(+), 9 deletions(-) [...] > @@ -794,12 +814,13 @@ void __init old_map_region(efi_memory_desc_t *md) > */ > void __init efi_enter_virtual_mode(void) > { > + pgd_t *pgd = (pgd_t *)__va(real_mode_header->trampoline_pgd); > + unsigned long size, new_memmap_left = 0; > efi_memory_desc_t *md, *prev_md = NULL; > + int count = 0, new_memmap_shift = 0; > void *p, *new_memmap = NULL; > - unsigned long size; > efi_status_t status; > u64 end, systab; > - int count = 0; > > efi.systab = NULL; You sunk my i386 battleship, /home/build/git/efi/arch/x86/platform/efi/efi.c:824:24: error: ‘struct real_mode_header’ has no member named ‘trampoline_pgd’ make[4]: *** [arch/x86/platform/efi/efi.o] Error 1 make[3]: *** [arch/x86/platform/efi] Error 2 -- Matt Fleming, Intel Open Source Technology Center -- To unsubscribe from this list: send the line "unsubscribe linux-efi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
