Laura Abbott <labbott@xxxxxxxxxx> writes: > Hi, > > This is v4 of the series to allow unique build ids in the kernel. As a > reminder of the context: > > "" > In Fedora, the debug information is packaged separately (foo-debuginfo) and > can be installed separately. There's been a long standing issue where only one > version of a debuginfo info package can be installed at a time. Mark Wielaard > made an effort for Fedora 27 to allow parallel installation of debuginfo (see > https://fedoraproject.org/wiki/Changes/ParallelInstallableDebuginfo for > more details) > > Part of the requirement to allow this to work is that build ids are > unique between builds. The existing upstream rpm implementation ensures > this by re-calculating the build-id using the version and release as a > seed. This doesn't work 100% for the kernel because of the vDSO which is > its own binary and doesn't get updated. After poking holes in a few of my > ideas, there was a discussion with some people from the binutils team about > adding --build-id-salt to let ld do the calculation debugedit is doing. There > was a counter proposal made to add in the salt while building. The > easiest proposal was to add an item in the linker script vs. linking in > an object since we need the salt to go in every module as well as the > kernel and vmlinux. > "" > > v4 takes Linus' suggestion of using linker fill to insert the build id. > This removes the need to use a generated header which makes things much > easier. One change is that because this section isn't .comment it won't > get stripped automatically. This is pretty small but I also know people > can be picky so I'm open to opinions or suggestions here. > > Laura Abbott (3): > scripts: Preprocess module-common.lds > kbuild: Introduce build-salt linker section and config option > x86: Add build salt to the vDSO and kernel linker scripts Hi Laura, Here's a patch to get it working on powerpc. Seems to work as expected. cheers >From fc5e22e4873956f9328e401ee5dd2835f4884db9 Mon Sep 17 00:00:00 2001 From: Michael Ellerman <mpe@xxxxxxxxxxxxxx> Date: Tue, 12 Jun 2018 14:52:34 +1000 Subject: [PATCH] powerpc: Add support for BUILD_SALT in kernel, modules & VDSO This patch adds support for BUILD_SALT in the kernel, modules and VDSO. See the commit that adds BUILD_SALT for more info. Kernel: 0:mon> d c000000001340840 c000000001340840 0055aaff12345678 1234567812345678 |.U...4Vx.4Vx.4Vx| c000000001340850 1234567812345678 1234567812345678 |.4Vx.4Vx.4Vx.4Vx| Module: $ cat/sys/module/kvm/sections/.salt 0xd0000000064385e8 ... 0:mon> d d0000000064385e8 d0000000064385e8 0055aaff12345678 1234567812345678 |.U...4Vx.4Vx.4Vx| d0000000064385f8 1234567812345678 1234567812345678 |.4Vx.4Vx.4Vx.4Vx| vdso: (gdb) x/4xw (0x7ffff7f80000 + 0x4a0) 0x7ffff7f804a0: 0xffaa5500 0x78563412 0x78563412 0x78563412 Signed-off-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx> --- arch/powerpc/kernel/vdso32/vdso32.lds.S | 2 ++ arch/powerpc/kernel/vdso64/vdso64.lds.S | 2 ++ arch/powerpc/kernel/vmlinux.lds.S | 1 + 3 files changed, 5 insertions(+) diff --git a/arch/powerpc/kernel/vdso32/vdso32.lds.S b/arch/powerpc/kernel/vdso32/vdso32.lds.S index 099a6db14e67..c06a12607777 100644 --- a/arch/powerpc/kernel/vdso32/vdso32.lds.S +++ b/arch/powerpc/kernel/vdso32/vdso32.lds.S @@ -4,6 +4,7 @@ * library */ #include <asm/vdso.h> +#include <asm-generic/vmlinux.lds.h> #ifdef __LITTLE_ENDIAN__ OUTPUT_FORMAT("elf32-powerpcle", "elf32-powerpcle", "elf32-powerpcle") @@ -25,6 +26,7 @@ SECTIONS .gnu.version_d : { *(.gnu.version_d) } .gnu.version_r : { *(.gnu.version_r) } + BUILD_SALT .note : { *(.note.*) } :text :note . = ALIGN(16); diff --git a/arch/powerpc/kernel/vdso64/vdso64.lds.S b/arch/powerpc/kernel/vdso64/vdso64.lds.S index 256fb9720298..ace69258446a 100644 --- a/arch/powerpc/kernel/vdso64/vdso64.lds.S +++ b/arch/powerpc/kernel/vdso64/vdso64.lds.S @@ -4,6 +4,7 @@ * library */ #include <asm/vdso.h> +#include <asm-generic/vmlinux.lds.h> #ifdef __LITTLE_ENDIAN__ OUTPUT_FORMAT("elf64-powerpcle", "elf64-powerpcle", "elf64-powerpcle") @@ -25,6 +26,7 @@ SECTIONS .gnu.version_d : { *(.gnu.version_d) } .gnu.version_r : { *(.gnu.version_r) } + BUILD_SALT .note : { *(.note.*) } :text :note . = ALIGN(16); diff --git a/arch/powerpc/kernel/vmlinux.lds.S b/arch/powerpc/kernel/vmlinux.lds.S index 5baac79df97e..59635369ceea 100644 --- a/arch/powerpc/kernel/vmlinux.lds.S +++ b/arch/powerpc/kernel/vmlinux.lds.S @@ -348,6 +348,7 @@ SECTIONS } BUG_TABLE + BUILD_SALT . = ALIGN(PAGE_SIZE); _edata = .; -- 2.14.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kbuild" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
