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authorNathan Chancellor2023-12-05 16:53:51 -0700
committerPalmer Dabbelt2024-01-17 18:08:27 -0800
commitae84ff9a14a5a8d36a329a30626800155782e617 (patch)
tree16b1769cb8952a7095455b596c7944d6ebeaffac
parent55b71d2ce133da893ffb1ecd69a34e1fee509292 (diff)
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: https://github.com/llvm/llvm-project/commit/bbc0f99f3bc96f1db16f649fc21dd18e5b0918f6 [1] Link: https://github.com/llvm/llvm-project/commit/1df5ea29b43690b6622db2cad7b745607ca4de6a [2] Link: https://github.com/llvm/llvm-project/commit/7ffabb61a5569444b5ac9322e22e5471cc5e4a77 [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>
-rw-r--r--arch/riscv/Kconfig9
-rw-r--r--lib/Kconfig.debug1
2 files changed, 10 insertions, 0 deletions
diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index 72be1d8122a3..81b473cb47b0 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -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
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index cc7d53d9dc01..a0ebce05a368 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -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