riscv: Select HAVE_DYNAMIC_FTRACE when -fpatchable-function-entry is available

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@intel.com>
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Fangrui Song <maskray@google.com>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>

diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index 82c469b..a840004 100644 (file)
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -231,7 +231,7 @@ 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