[PATCH] arm64: fix selection of HAVE_DYNAMIC_FTRACE_WITH_ARGS

Mark Rutland mark.rutland at arm.com
Mon Sep 30 05:04:48 PDT 2024


The Kconfig logic to select HAVE_DYNAMIC_FTRACE_WITH_ARGS is incorrect,
and HAVE_DYNAMIC_FTRACE_WITH_ARGS may be selected when it is not
supported by the combination of clang and GNU LD, resulting in link-time
errors:

  aarch64-linux-gnu-ld: .init.data has both ordered [`__patchable_function_entries' in init/main.o] and unordered [`.meminit.data' in mm/sparse.o] sections
  aarch64-linux-gnu-ld: final link failed: bad value

... which can be seen when building with CC=clang using a binutils
version older than 2.36.

We originally fixed that in commit:

  45bd8951806eb5e8 ("arm64: Improve HAVE_DYNAMIC_FTRACE_WITH_REGS selection for clang")

... by splitting the "select HAVE_DYNAMIC_FTRACE_WITH_ARGS" statement
into separete CLANG_SUPPORTS_DYNAMIC_FTRACE_WITH_ARGS and
GCC_SUPPORTS_DYNAMIC_FTRACE_WITH_ARGS options which individually select
HAVE_DYNAMIC_FTRACE_WITH_ARGS.

Subsequently we accidentally re-introduced the common "select
HAVE_DYNAMIC_FTRACE_WITH_ARGS" statement in commit:

  26299b3f6ba26bfc ("ftrace: arm64: move from REGS to ARGS")

... then we removed it again in commit:

  68a63a412d18bd2e ("arm64: Fix build with CC=clang, CONFIG_FTRACE=y and CONFIG_STACK_TRACER=y")

... then we accidentally re-introduced it again in commit:

  2aa6ac03516d078c ("arm64: ftrace: Add direct call support")

Fix this for the third time by keeping the unified select statement and
making this depend onf either GCC_SUPPORTS_DYNAMIC_FTRACE_WITH_ARGS or
CLANG_SUPPORTS_DYNAMIC_FTRACE_WITH_ARGS. This is more consistent with
usual style and less likely to go wrong in future.

Fixes: 2aa6ac03516d078c ("arm64: ftrace: Add direct call support")
Signed-off-by: Mark Rutland <mark.rutland at arm.com>
Cc: Will Deacon <will at kernel.org>
Cc: Catalin Marians <catalin.marinas at arm.com>
---
 arch/arm64/Kconfig | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 3e29b44d2d7bd..fd22eed3a683a 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -200,7 +200,8 @@ config ARM64
 	select HAVE_DMA_CONTIGUOUS
 	select HAVE_DYNAMIC_FTRACE
 	select HAVE_DYNAMIC_FTRACE_WITH_ARGS \
-		if $(cc-option,-fpatchable-function-entry=2)
+		if (GCC_SUPPORTS_DYNAMIC_FTRACE_WITH_ARGS || \
+		    CLANG_SUPPORTS_DYNAMIC_FTRACE_WITH_ARGS)
 	select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS \
 		if DYNAMIC_FTRACE_WITH_ARGS && DYNAMIC_FTRACE_WITH_CALL_OPS
 	select HAVE_DYNAMIC_FTRACE_WITH_CALL_OPS \
@@ -286,12 +287,10 @@ config CLANG_SUPPORTS_DYNAMIC_FTRACE_WITH_ARGS
 	def_bool CC_IS_CLANG
 	# https://github.com/ClangBuiltLinux/linux/issues/1507
 	depends on AS_IS_GNU || (AS_IS_LLVM && (LD_IS_LLD || LD_VERSION >= 23600))
-	select HAVE_DYNAMIC_FTRACE_WITH_ARGS
 
 config GCC_SUPPORTS_DYNAMIC_FTRACE_WITH_ARGS
 	def_bool CC_IS_GCC
 	depends on $(cc-option,-fpatchable-function-entry=2)
-	select HAVE_DYNAMIC_FTRACE_WITH_ARGS
 
 config 64BIT
 	def_bool y
-- 
2.30.2




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