[PATCH] LoongArch: uprobes: make UPROBE_SWBP_INSN/UPROBE_XOLBP_INSN constant

[Oleg Nesterov]

LoongArch defines UPROBE_SWBP_INSN as a function call and this breaks
arch_uprobe_trampoline() which uses it to initialize a static variable.

Fixes: ff474a78cef5 ("uprobe: Add uretprobe syscall to speed up return probe")
Reported-by: Nathan Chancellor <nathan@xxxxxxxxxx>
Closes: https://lore.kernel.org/all/20240614174822.GA1185149@thelio-3990X/
Suggested-by: Andrii Nakryiko <andrii@xxxxxxxxxx>
Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx>
---
 arch/loongarch/include/asm/uprobes.h | 6 ++++--
 arch/loongarch/kernel/uprobes.c      | 8 ++++++++
 2 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/arch/loongarch/include/asm/uprobes.h b/arch/loongarch/include/asm/uprobes.h
index c8f59983f702..18221eb9a8b0 100644
--- a/arch/loongarch/include/asm/uprobes.h
+++ b/arch/loongarch/include/asm/uprobes.h
@@ -6,13 +6,15 @@
 
 typedef u32 uprobe_opcode_t;
 
+#define __emit_break(imm)	(uprobe_opcode_t)((imm) | (break_op << 15))
+
 #define MAX_UINSN_BYTES		8
 #define UPROBE_XOL_SLOT_BYTES	MAX_UINSN_BYTES
 
-#define UPROBE_SWBP_INSN	larch_insn_gen_break(BRK_UPROBE_BP)
+#define UPROBE_SWBP_INSN	__emit_break(BRK_UPROBE_BP)
 #define UPROBE_SWBP_INSN_SIZE	LOONGARCH_INSN_SIZE
 
-#define UPROBE_XOLBP_INSN	larch_insn_gen_break(BRK_UPROBE_XOLBP)
+#define UPROBE_XOLBP_INSN	__emit_break(BRK_UPROBE_XOLBP)
 
 struct arch_uprobe {
 	unsigned long	resume_era;
diff --git a/arch/loongarch/kernel/uprobes.c b/arch/loongarch/kernel/uprobes.c
index 87abc7137b73..90462d94c28f 100644
--- a/arch/loongarch/kernel/uprobes.c
+++ b/arch/loongarch/kernel/uprobes.c
@@ -7,6 +7,14 @@
 
 #define UPROBE_TRAP_NR	UINT_MAX
 
+static __init int check_emit_break(void)
+{
+	BUG_ON(UPROBE_SWBP_INSN  != larch_insn_gen_break(BRK_UPROBE_BP));
+	BUG_ON(UPROBE_XOLBP_INSN != larch_insn_gen_break(BRK_UPROBE_XOLBP));
+	return 0;
+}
+arch_initcall(check_emit_break);
+
 int arch_uprobe_analyze_insn(struct arch_uprobe *auprobe,
 			     struct mm_struct *mm, unsigned long addr)
 {
-- 
2.25.1.362.g51ebf55