diff mbox

[1/2] arm64: bpf: fix JIT frame pointer setup

Message ID 1447365421-1309-2-git-send-email-yang.shi@linaro.org (mailing list archive)
State New, archived
Headers show

Commit Message

Yang Shi Nov. 12, 2015, 9:57 p.m. UTC 
BPF fp should point to the top of the BPF prog stack. The original
implementation made it point to the bottom incorrectly.
Move A64_SP to fp before reserve BPF prog stack space.

CC: Zi Shen Lim <zlim.lnx@gmail.com>
CC: Xi Wang <xi.wang@gmail.com>
Signed-off-by: Yang Shi <yang.shi@linaro.org>
---
 arch/arm64/net/bpf_jit_comp.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

Comments

Zi Shen Lim Nov. 13, 2015, 3:21 a.m. UTC | #1 
On Thu, Nov 12, 2015 at 1:57 PM, Yang Shi <yang.shi@linaro.org> wrote:
> BPF fp should point to the top of the BPF prog stack. The original
> implementation made it point to the bottom incorrectly.
> Move A64_SP to fp before reserve BPF prog stack space.
>
> CC: Zi Shen Lim <zlim.lnx@gmail.com>
> CC: Xi Wang <xi.wang@gmail.com>
> Signed-off-by: Yang Shi <yang.shi@linaro.org>
> ---

Reviewed-by: Zi Shen Lim <zlim.lnx@gmail.com>

Also,

Fixes: e54bcde3d69d ("arm64: eBPF JIT compiler")
Cc: <stable@vger.kernel.org> # 3.18+
David Miller Nov. 16, 2015, 7:39 p.m. UTC | #2 
From: Yang Shi <yang.shi@linaro.org>
Date: Thu, 12 Nov 2015 13:57:00 -0800

> BPF fp should point to the top of the BPF prog stack. The original
> implementation made it point to the bottom incorrectly.
> Move A64_SP to fp before reserve BPF prog stack space.
> 
> CC: Zi Shen Lim <zlim.lnx@gmail.com>
> CC: Xi Wang <xi.wang@gmail.com>
> Signed-off-by: Yang Shi <yang.shi@linaro.org>

Applied.
diff mbox

Patch

diff --git a/arch/arm64/net/bpf_jit_comp.c b/arch/arm64/net/bpf_jit_comp.c
index a44e529..ac8b548 100644
--- a/arch/arm64/net/bpf_jit_comp.c
+++ b/arch/arm64/net/bpf_jit_comp.c
@@ -161,12 +161,12 @@  static void build_prologue(struct jit_ctx *ctx)
 	if (ctx->tmp_used)
 		emit(A64_PUSH(tmp1, tmp2, A64_SP), ctx);
 
-	/* Set up BPF stack */
-	emit(A64_SUB_I(1, A64_SP, A64_SP, stack_size), ctx);
-
 	/* Set up frame pointer */
 	emit(A64_MOV(1, fp, A64_SP), ctx);
 
+	/* Set up BPF stack */
+	emit(A64_SUB_I(1, A64_SP, A64_SP, stack_size), ctx);
+
 	/* Clear registers A and X */
 	emit_a64_mov_i64(ra, 0, ctx);
 	emit_a64_mov_i64(rx, 0, ctx);