[PATCH 5.12 184/363] riscv: Select HAVE_DYNAMIC_FTRACE when -fpatchable-function-entry is available

From: Greg Kroah-Hartman
Date: Mon May 17 2021 - 10:25:47 EST


From: Nathan Chancellor <nathan@xxxxxxxxxx>

[ Upstream commit adebc8817b5c975d598ac379bbdf67a7a5186ade ]

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.

Fixes: afc76b8b8011 ("riscv: Using PATCHABLE_FUNCTION_ENTRY instead of MCOUNT")
Link: https://github.com/ClangBuiltLinux/linux/issues/1268
Reported-by: kernel test robot <lkp@xxxxxxxxx>
Signed-off-by: Nathan Chancellor <nathan@xxxxxxxxxx>
Reviewed-by: Fangrui Song <maskray@xxxxxxxxxx>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
arch/riscv/Kconfig | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index 4515a10c5d22..d9522fc35ca5 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
--
2.30.2