[PATCH] uprobe: Do not use UPROBE_SWBP_INSN as static initializer

Jiri Olsa
2024-06-18T19:43:11Z

Nathan reported compilation fail for loongarch arch:

kernel/events/uprobes.c: In function 'arch_uprobe_trampoline':
arch/loongarch/include/asm/uprobes.h:12:33: error: initializer element is not constant
12 | #define UPROBE_SWBP_INSN larch_insn_gen_break(BRK_UPROBE_BP)
| ^~~~~~~~~~~~~~~~~~~~
kernel/events/uprobes.c:1479:39: note: in expansion of macro 'UPROBE_SWBP_INSN'
1479 | static uprobe_opcode_t insn = UPROBE_SWBP_INSN;

Loongarch defines UPROBE_SWBP_INSN as function call, so we can't
use it to initialize static variable.

Cc: Oleg Nesterov <oleg@redhat.com>
Fixes: ff474a78cef5 ("uprobe: Add uretprobe syscall to speed up return probe")
Reported-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
---
kernel/events/uprobes.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
index 2816e65729ac..6986bd993702 100644
--- a/kernel/events/uprobes.c
+++ b/kernel/events/uprobes.c
@@ -1476,8 +1476,9 @@ static int xol_add_vma(struct mm_struct *mm, struct xol_area *area)

void * __weak arch_uprobe_trampoline(unsigned long *psize)
{
- static uprobe_opcode_t insn = UPROBE_SWBP_INSN;
+ static uprobe_opcode_t insn;

+ insn = insn ?: UPROBE_SWBP_INSN;
*psize = UPROBE_SWBP_INSN_SIZE;
return &insn;
}
--
2.45.1