On 2 February 2017 at 18:30, Will Deacon <will.deacon@xxxxxxx> wrote: > Hi Ard, > > On Thu, Feb 02, 2017 at 05:33:19PM +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. >> This allows a debug EFI build to find the vmlinux binary, which is >> very helpful in debugging, given that the offset where the Image is >> first loaded by EFI is highly unpredictable. >> >> On implementations of UEFI that choose to implement it, this >> information is exposed via the EFI debug support table, which is a UEFI >> configuration table that is accessible both by the firmware at boot time >> and by the OS at runtime, and lists all PE/COFF images loaded by the >> system. >> >> The format of the NB10 Codeview entry is based on the definition used >> by EDK2, which is our primary reference when it comes to the use of >> PE/COFF in the context of UEFI firmware. >> >> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx> >> --- >> v4: add a separate DEBUG_EFI debug option so that this feature is disabled >> by default >> dropped 1/2 which has been queued already in the EFI tree >> use ASCII rather than an opaque constant for "NB10" signature >> >> arch/arm64/Kconfig.debug | 8 ++++ >> arch/arm64/kernel/Makefile | 4 ++ >> arch/arm64/kernel/head.S | 47 +++++++++++++++++++- >> 3 files changed, 58 insertions(+), 1 deletion(-) >> >> diff --git a/arch/arm64/Kconfig.debug b/arch/arm64/Kconfig.debug >> index d1ebd46872fd..f7f38b1aab14 100644 >> --- a/arch/arm64/Kconfig.debug >> +++ b/arch/arm64/Kconfig.debug >> @@ -95,6 +95,14 @@ config DEBUG_ALIGN_RODATA >> >> If in doubt, say N. >> >> +config DEBUG_EFI >> + depends on EFI && DEBUG_INFO >> + bool "UEFI debugging" >> + help >> + Enable this option to include EFI specific debugging features into >> + the kernel that are only useful when using a debug build of the >> + UEFI firmware >> + > > I don't much like embedding the absolute host build path in the kernel > image, but if that's what the tools expect then so be it. > >> source "drivers/hwtracing/coresight/Kconfig" >> >> endmenu >> diff --git a/arch/arm64/kernel/Makefile b/arch/arm64/kernel/Makefile >> index 7d66bbaafc0c..2600c60337ac 100644 >> --- a/arch/arm64/kernel/Makefile >> +++ b/arch/arm64/kernel/Makefile >> @@ -55,3 +55,7 @@ obj-y += $(arm64-obj-y) vdso/ probes/ >> obj-m += $(arm64-obj-m) >> head-y := head.o >> extra-y += $(head-y) vmlinux.lds >> + >> +ifeq ($(CONFIG_DEBUG_EFI),y) >> +AFLAGS_head.o += -DVMLINUX_PATH="\"$(shell readlink -f $(objtree)/vmlinux)\"" >> +endif > > Can we use the Make realpath directive instead of calling out to the shell? > Yep. This works as expected: diff --git a/arch/arm64/kernel/Makefile b/arch/arm64/kernel/Makefile index 2600c60337ac..1606c6b2a280 100644 --- a/arch/arm64/kernel/Makefile +++ b/arch/arm64/kernel/Makefile @@ -57,5 +57,5 @@ head-y := head.o extra-y += $(head-y) vmlinux.lds ifeq ($(CONFIG_DEBUG_EFI),y) -AFLAGS_head.o += -DVMLINUX_PATH="\"$(shell readlink -f $(objtree)/vmlinux)\"" +AFLAGS_head.o += -DVMLINUX_PATH="\"$(realpath $(objtree)/vmlinux)\"" endif > Do you want me to merge this via arm64? > Yes, please -- 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
