Unverified Commit 5f1a58ed authored by Juhan Jin's avatar Juhan Jin Committed by Alexandre Ghiti
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riscv: ftrace: Add parentheses in macro definitions of make_call_t0 and make_call_ra 



This patch adds parentheses to parameters caller and callee of macros
make_call_t0 and make_call_ra. Every existing invocation of these two
macros uses a single variable for each argument, so the absence of the
parentheses seems okay. However, future invocations might use more
complex expressions as arguments. For example, a future invocation might
look like this: make_call_t0(a - b, c, call). Without parentheses in the
macro definition, the macro invocation expands to:

...
unsigned int offset = (unsigned long) c - (unsigned long) a - b;
...

which is clearly wrong.

The use of parentheses ensures arguments are correctly evaluated and
potentially saves future users of make_call_t0 and make_call_ra debugging
trouble.

Fixes: 6724a76c ("riscv: ftrace: Reduce the detour code size to half")
Signed-off-by: default avatarJuhan Jin <juhan.jin@foxmail.com>
Reviewed-by: default avatarAlexandre Ghiti <alexghiti@rivosinc.com>
Link: https://lore.kernel.org/r/tencent_AE90AA59903A628E87E9F80E563DA5BA5508@qq.com


Signed-off-by: default avatarAlexandre Ghiti <alexghiti@rivosinc.com>
parent 82e81b89

arch/riscv/include/asm/ftrace.h

+2 −2
Original line number Diff line number Diff line
@@ -92,7 +92,7 @@ struct dyn_arch_ftrace { 
#define make_call_t0(caller, callee, call)				\

do {									\

	unsigned int offset =						\

		(unsigned long) callee - (unsigned long) caller;	\

		(unsigned long) (callee) - (unsigned long) (caller);	\

	call[0] = to_auipc_t0(offset);					\

	call[1] = to_jalr_t0(offset);					\

} while (0)
@@ -108,7 +108,7 @@ do { \ 
#define make_call_ra(caller, callee, call)				\

do {									\

	unsigned int offset =						\

		(unsigned long) callee - (unsigned long) caller;	\

		(unsigned long) (callee) - (unsigned long) (caller);	\

	call[0] = to_auipc_ra(offset);					\

	call[1] = to_jalr_ra(offset);					\

} while (0)