Commit b3d6bdfe authored by Nathan Chancellor's avatar Nathan Chancellor Committed by Palmer Dabbelt

riscv: Adjust dependencies of HAVE_DYNAMIC_FTRACE selection

When building allmodconfig with clang and its integrated assembler and
linking with a version of GNU ld prior to 2.36, the following link error
occurs:

  riscv64-linux-gnu-ld: .init.data has both ordered [`__patchable_function_entries' in init/main.o] and unordered [`.init_array.0' in kernel/trace/trace_benchmark.o] sections
  riscv64-linux-gnu-ld: final link failed: bad value

This is the same error addressed by commit 45bd8951 ("arm64: Improve
HAVE_DYNAMIC_FTRACE_WITH_REGS selection for clang") for arm64. See that
changelog for a full description of why this error occurs with this
combination of tools.

In a similar manner as that change, restrict the
CONFIG_HAVE_DYNAMIC_FTRACE selection to combinations of tools known to
work so that there are no errors.

Link: https://github.com/ClangBuiltLinux/linux/issues/1817Signed-off-by: default avatarNathan Chancellor <nathan@kernel.org>
Reviewed-by: default avatarConor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20230404-riscv-dynamic-ftrace-checks-clang-v1-1-0ce296b7d423@kernel.orgSigned-off-by: default avatarPalmer Dabbelt <palmer@rivosinc.com>
parent 89d77f71
......@@ -142,12 +142,23 @@ config RISCV
select TRACE_IRQFLAGS_SUPPORT
select UACCESS_MEMCPY if !MMU
select ZONE_DMA32 if 64BIT
select HAVE_DYNAMIC_FTRACE if !XIP_KERNEL && MMU && $(cc-option,-fpatchable-function-entry=8)
select HAVE_DYNAMIC_FTRACE if !XIP_KERNEL && MMU && (CLANG_SUPPORTS_DYNAMIC_FTRACE || GCC_SUPPORTS_DYNAMIC_FTRACE)
select HAVE_DYNAMIC_FTRACE_WITH_REGS if HAVE_DYNAMIC_FTRACE
select HAVE_FTRACE_MCOUNT_RECORD if !XIP_KERNEL
select HAVE_FUNCTION_GRAPH_TRACER
select HAVE_FUNCTION_TRACER if !XIP_KERNEL && !PREEMPTION
config CLANG_SUPPORTS_DYNAMIC_FTRACE
def_bool CC_IS_CLANG
# https://github.com/llvm/llvm-project/commit/6ab8927931851bb42b2c93a00801dc499d7d9b1e
depends on CLANG_VERSION >= 130000
# https://github.com/ClangBuiltLinux/linux/issues/1817
depends on AS_IS_GNU || (AS_IS_LLVM && (LD_IS_LLD || LD_VERSION >= 23600))
config GCC_SUPPORTS_DYNAMIC_FTRACE
def_bool CC_IS_GCC
depends on $(cc-option,-fpatchable-function-entry=8)
config ARCH_MMAP_RND_BITS_MIN
default 18 if 64BIT
default 8
......
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