[PATCH bpf-next v1 3/7] bpf, arm64: Use resolved pointer for timed may_goto

[Siddharth Chintamaneni]

The timed may_goto fixup now passes the resolved counter pointer through
BPF_REG_AX instead of a stack offset.

Copy the pointer directly into the first argument register rather than
adding it to the BPF frame pointer again.

Fixes: 16175375da36 ("bpf, arm64: Add JIT support for timed may_goto")
Reported-by: Jeremy Jean <jeremy.jean at oss.cyber.gouv.fr>
Link: https://lore.kernel.org/all/20260824213158.3755932-2-Jeremy.Jean@oss.cyber.gouv.fr/
Assisted-by: Copilot:gpt-5.6-sol
Signed-off-by: Siddharth Chintamaneni <sidchintamaneni at gmail.com>
---
 arch/arm64/net/bpf_timed_may_goto.S | 12 +++---------
 1 file changed, 3 insertions(+), 9 deletions(-)

diff --git a/arch/arm64/net/bpf_timed_may_goto.S b/arch/arm64/net/bpf_timed_may_goto.S
index a9a802711a7f..53148c9a1c58 100644
--- a/arch/arm64/net/bpf_timed_may_goto.S
+++ b/arch/arm64/net/bpf_timed_may_goto.S
@@ -14,16 +14,10 @@ SYM_FUNC_START(arch_bpf_timed_may_goto)
 	stp	x3, x4, [sp, #48]
 
 	/*
-	 * Stack depth was passed in BPF_REG_AX (x9), add it to the BPF_FP
-	 * (x25) to get the pointer to count and timestamp and pass it as the
-	 * first argument in x0.
-	 *
-	 * Before generating the call to arch_bpf_timed_may_goto, the verifier
-	 * generates a load instruction using FP, i.e. REG_AX = *(u64 *)(FP -
-	 * stack_off_cnt), so BPF_REG_FP (x25) is always set up by the arm64
-	 * jit in this case.
+	 * BPF_REG_AX (x9) contains the count and timestamp pointer; pass it as
+	 * the first argument in x0.
 	 */
-	add	x0, x9, x25
+	mov	x0, x9
 	bl	bpf_check_timed_may_goto
 	/* BPF_REG_AX(x9) will be stored into count, so move return value to it. */
 	mov	x9, x0
-- 
2.43.0