On 2021-03-25, Nathan Chancellor wrote:
clang prior to 13.0.0 does not support -fpatchable-function-entry for
RISC-V.
clang: error: unsupported option '-fpatchable-function-entry=8' for target
'riscv64-unknown-linux-gnu'
To avoid this error, only select HAVE_DYNAMIC_FTRACE when this option is
not available.
If clang -fpatchable-function-entry=8 does not error "unsupported
option" for one target, it means the backend feature is supported on
this target.
Reviewed-by: Fangrui Song <mask...@google.com>
Fixes: afc76b8b8011 ("riscv: Using PATCHABLE_FUNCTION_ENTRY instead of MCOUNT")
Link: https://github.com/ClangBuiltLinux/linux/issues/1268
Reported-by: kernel test robot <l...@intel.com>
Signed-off-by: Nathan Chancellor <nat...@kernel.org>
---
arch/riscv/Kconfig | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index 87d7b52f278f..ba1d07640b66 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -227,7 +227,7 @@ config ARCH_RV64I
bool "RV64I"
select 64BIT
select ARCH_SUPPORTS_INT128 if CC_HAS_INT128 && GCC_VERSION >= 50000
- select HAVE_DYNAMIC_FTRACE if MMU
+ select HAVE_DYNAMIC_FTRACE if MMU &&
$(cc-option,-fpatchable-function-entry=8)
select HAVE_DYNAMIC_FTRACE_WITH_REGS if HAVE_DYNAMIC_FTRACE
select HAVE_FTRACE_MCOUNT_RECORD
select HAVE_FUNCTION_GRAPH_TRACER
--
2.31.0
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