On 25 January 2017 at 11:53, Mark Rutland <mark.rutland@xxxxxxx> wrote: > On Wed, Jan 25, 2017 at 10:39:19AM +0000, Ard Biesheuvel wrote: >> When building with debugging symbols, take the absolute path to the >> vmlinux binary and add it to the special PE/COFF debug table entry. >> >> These entries are used internally by EDK2 based* debug builds of UEFI >> to populate the DebugImageInfo table, which can be used by debuggers >> as well as by the OS itself to retrieve information about all loaded >> PE/COFF executables. This is highly useful for source level debugging >> of the UEFI stub. > > Does that mean EFI_IMAGE_DEBUG_DIRECTORY_ENTRY and friends are > EDK2-specific? > > Or just that the way EDK2 happens to use those is EDK2-specific? > Those values are defined by the PE/COFF spec, and I assume that a CodeView type entry in the debug table usually contains a NUL terminated string as well, given that the EDK2 crowd is very Wintel-heavy. The significance of mentioning EDK2 here was that I thought that the DebugImageInfo table was a PI construct rather than something described in the UEFI spec. But looking more carefully, it seems that this table is in fact a UEFI construct, so I should probably drop this mention from the commit log >> * for AArch64, this probably means all of them >> >> Cc: Matt Fleming <matt@xxxxxxxxxxxxxxxxxxx> >> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx> >> --- >> arch/arm64/kernel/Makefile | 4 +++ >> arch/arm64/kernel/head.S | 34 +++++++++++++++++++- >> arch/arm64/kernel/image.h | 3 ++ >> 3 files changed, 40 insertions(+), 1 deletion(-) > >> +efi_debug_table: >> + // EFI_IMAGE_DEBUG_DIRECTORY_ENTRY >> + .long 0 // Characteristics >> + .long 0 // TimeDateStamp >> + .short 0 // MajorVersion >> + .short 0 // MinorVersion >> + .long 2 // Type == EFI_IMAGE_DEBUG_TYPE_CODEVIEW > >> +ENTRY(efi_debug_entry) >> + // EFI_IMAGE_DEBUG_CODEVIEW_NB10_ENTRY >> + .long 0x3031424E // Signature > > Certainly not a blocker for this, but this reminds me that it would be > nice to de-magic the EFI constants used by the stub. > > I took a stab a while back [1], for the existing definitions, but that > fell by the wayside. > Good point. -- 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
