5.15-stable review patch. If anyone has any objections, please let me know.
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From: Juhan Jin juhan.jin@foxmail.com
[ Upstream commit 5f1a58ed91a040d4625d854f9bb3dd4995919202 ]
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: 6724a76cff85 ("riscv: ftrace: Reduce the detour code size to half") Signed-off-by: Juhan Jin juhan.jin@foxmail.com Reviewed-by: Alexandre Ghiti alexghiti@rivosinc.com Link: https://lore.kernel.org/r/tencent_AE90AA59903A628E87E9F80E563DA5BA5508@qq.co... Signed-off-by: Alexandre Ghiti alexghiti@rivosinc.com Signed-off-by: Sasha Levin sashal@kernel.org --- arch/riscv/include/asm/ftrace.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/arch/riscv/include/asm/ftrace.h b/arch/riscv/include/asm/ftrace.h index d47d87c2d7e3d..195f4ebd71f2c 100644 --- a/arch/riscv/include/asm/ftrace.h +++ b/arch/riscv/include/asm/ftrace.h @@ -77,7 +77,7 @@ 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) @@ -93,7 +93,7 @@ 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)