This is a note to let you know that I've just added the patch titled
LoongArch: BPF: Fix check condition to call lu32id in move_imm()
to the 6.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
loongarch-bpf-fix-check-condition-to-call-lu32id-in-move_imm.patch
and it can be found in the queue-6.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 4eece7e6de94d833c8aeed2f438faf487cbf94ff Mon Sep 17 00:00:00 2001
From: Tiezhu Yang <yangtiezhu@xxxxxxxxxxx>
Date: Fri, 28 Jul 2023 10:30:42 +0800
Subject: LoongArch: BPF: Fix check condition to call lu32id in move_imm()
From: Tiezhu Yang <yangtiezhu@xxxxxxxxxxx>
commit 4eece7e6de94d833c8aeed2f438faf487cbf94ff upstream.
As the code comment says, the initial aim is to reduce one instruction
in some corner cases, if bit[51:31] is all 0 or all 1, no need to call
lu32id. That is to say, it should call lu32id only if bit[51:31] is not
all 0 and not all 1. The current code always call lu32id, the result is
right but the logic is unexpected and wrong, fix it.
Cc: stable@xxxxxxxxxxxxxxx # 6.1
Fixes: 5dc615520c4d ("LoongArch: Add BPF JIT support")
Reported-by: Colin King (gmail) <colin.i.king@xxxxxxxxx>
Closes: https://lore.kernel.org/all/bcf97046-e336-712a-ac68-7fd194f2953e@xxxxxxxxx/
Signed-off-by: Tiezhu Yang <yangtiezhu@xxxxxxxxxxx>
Signed-off-by: Huacai Chen <chenhuacai@xxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/loongarch/net/bpf_jit.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/arch/loongarch/net/bpf_jit.h
+++ b/arch/loongarch/net/bpf_jit.h
@@ -150,7 +150,7 @@ static inline void move_imm(struct jit_c
* no need to call lu32id to do a new filled operation.
*/
imm_51_31 = (imm >> 31) & 0x1fffff;
- if (imm_51_31 != 0 || imm_51_31 != 0x1fffff) {
+ if (imm_51_31 != 0 && imm_51_31 != 0x1fffff) {
/* lu32id rd, imm_51_32 */
imm_51_32 = (imm >> 32) & 0xfffff;
emit_insn(ctx, lu32id, rd, imm_51_32);
Patches currently in stable-queue which might be from yangtiezhu@xxxxxxxxxxx are
queue-6.4/loongarch-bpf-fix-check-condition-to-call-lu32id-in-move_imm.patch
