linux-kernel - [PATCH v2] ARC: bpf: Correct conditional check in 'check_jmp

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Message-ID: <20241113134142.14970-1-hardevsinh.palaniya@siliconsignals.io>
Date: Wed, 13 Nov 2024 19:11:18 +0530
From: Hardevsinh Palaniya <hardevsinh.palaniya@...iconsignals.io>
To: ast@...nel.org,
	vadim.fedorenko@...ux.dev,
	list+bpf@...edi.org
Cc: tarang.raval@...iconsignals.io,
	Hardevsinh Palaniya <hardevsinh.palaniya@...iconsignals.io>,
	Daniel Borkmann <daniel@...earbox.net>,
	Andrii Nakryiko <andrii@...nel.org>,
	Martin KaFai Lau <martin.lau@...ux.dev>,
	Eduard Zingerman <eddyz87@...il.com>,
	Song Liu <song@...nel.org>,
	Yonghong Song <yonghong.song@...ux.dev>,
	John Fastabend <john.fastabend@...il.com>,
	KP Singh <kpsingh@...nel.org>,
	Stanislav Fomichev <sdf@...ichev.me>,
	Hao Luo <haoluo@...gle.com>,
	Jiri Olsa <jolsa@...nel.org>,
	Vineet Gupta <vgupta@...nel.org>,
	bpf@...r.kernel.org,
	linux-snps-arc@...ts.infradead.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH v2] ARC: bpf: Correct conditional check in 'check_jmp_32'

The original code checks 'if (ARC_CC_AL)', which is always true since
ARC_CC_AL is a constant. This makes the check redundant and likely
obscures the intention of verifying whether the jump is conditional.

Updates the code to check cond == ARC_CC_AL instead, reflecting the intent
to differentiate conditional from unconditional jumps.

Suggested-by: Vadim Fedorenko <vadim.fedorenko@...ux.dev>
Signed-off-by: Hardevsinh Palaniya <hardevsinh.palaniya@...iconsignals.io>
---

Changelog in V2:

- Changed subject line
- Updated condition check to 'if (cond == ARC_CC_AL)' instead of removing it

Link for v1: https://lore.kernel.org/bpf/e6d27adb-151c-46c1-9668-1cd2b492321b@linux.dev/T/#t
---
 arch/arc/net/bpf_jit_arcv2.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arc/net/bpf_jit_arcv2.c b/arch/arc/net/bpf_jit_arcv2.c
index 4458e409ca0a..6d989b6d88c6 100644
--- a/arch/arc/net/bpf_jit_arcv2.c
+++ b/arch/arc/net/bpf_jit_arcv2.c
@@ -2916,7 +2916,7 @@ bool check_jmp_32(u32 curr_off, u32 targ_off, u8 cond)
 	addendum = (cond == ARC_CC_AL) ? 0 : INSN_len_normal;
 	disp = get_displacement(curr_off + addendum, targ_off);
 
-	if (ARC_CC_AL)
+	if (cond == ARC_CC_AL)
 		return is_valid_far_disp(disp);
 	else
 		return is_valid_near_disp(disp);
-- 
2.43.0