mirrors
/
linux-stable
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
1
0
Fork 0
Code Issues Releases Wiki Activity

riscv: Restrict DWARF5 when building with LLVM to known working versions 

LLVM prior to 18.0.0 would generate incorrect debug info for DWARF5 due
to linker relaxation, which was worked around in clang by defaulting
RISC-V to DWARF4 [1]. Unfortunately, this workaround does not work for
the kernel because the DWARF version can be independently changed from
the default in Kconfig.

Do not allow DWARF5 to be selected for RISC-V when using linker
relaxation (ld.lld >= 15.0.0) and a version of LLVM that does not have
the fixes (the integrated assembler [2] and ld.lld [3] < 18.0.0)
necessary to generate the correct debug info.

Link: bbc0f99f3b [1]
Link: 1df5ea29b4 [2]
Link: 7ffabb61a5 [3]
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Fangrui Song <maskray@google.com>
Link: https://lore.kernel.org/r/20231205-riscv-restrict-dwarf5-llvm-v2-2-aedf00a382ac@kernel.org
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
This commit is contained in:
Nathan Chancellor 2023-12-05 16:53:51 -07:00 committed by Palmer Dabbelt
parent 55b71d2ce1
commit ae84ff9a14
No known key found for this signature in database
GPG Key ID: 2E1319F35FBB1889
2 changed files with 10 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

9
arch/riscv/Kconfig
View File

@ -186,6 +186,15 @@ config RISCV_USE_LINKER_RELAXATION
# https://github.com/llvm/llvm-project/commit/6611d58f5bbcbec77262d392e2923e1d680f6985
depends on !LD_IS_LLD || LLD_VERSION >= 150000
# https://github.com/llvm/llvm-project/commit/bbc0f99f3bc96f1db16f649fc21dd18e5b0918f6
config ARCH_HAS_BROKEN_DWARF5
def_bool y
depends on RISCV_USE_LINKER_RELAXATION
# https://github.com/llvm/llvm-project/commit/1df5ea29b43690b6622db2cad7b745607ca4de6a
depends on AS_IS_LLVM && AS_VERSION < 180000
# https://github.com/llvm/llvm-project/commit/7ffabb61a5569444b5ac9322e22e5471cc5e4a77
depends on LD_IS_LLD && LLD_VERSION < 180000
config ARCH_MMAP_RND_BITS_MIN
default 18 if 64BIT
default 8

1
lib/Kconfig.debug
View File

@ -282,6 +282,7 @@ config DEBUG_INFO_DWARF4
config DEBUG_INFO_DWARF5
bool "Generate DWARF Version 5 debuginfo"
select DEBUG_INFO
depends on !ARCH_HAS_BROKEN_DWARF5
depends on !CC_IS_CLANG || AS_IS_LLVM || (AS_IS_GNU && AS_VERSION >= 23502 && AS_HAS_NON_CONST_LEB128)
help
Generate DWARF v5 debug info. Requires binutils 2.35.2, gcc 5.0+ (gcc