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From: Huacai Chen <chenhuacai@loongson.cn>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Sasha Levin <sashal@kernel.org>,
	Huacai Chen <chenhuacai@kernel.org>
Cc: Xuerui Wang <kernel@xen0n.name>,
	stable@vger.kernel.org, linux-kernel@vger.kernel.org,
	loongarch@lists.linux.dev, Tiezhu Yang <yangtiezhu@loongson.cn>,
	Huacai Chen <chenhuacai@loongson.cn>
Subject: [PATCH for 6.12] LoongArch: Remove unnecessary checks for ORC unwinder
Date: Mon, 13 Apr 2026 10:23:14 +0800	[thread overview]
Message-ID: <20260413022314.1238307-1-chenhuacai@loongson.cn> (raw)

From: Tiezhu Yang <yangtiezhu@loongson.cn>

According to the following function definitions, __kernel_text_address()
already checks __module_text_address(), so it should remove the check of
__module_text_address() in bt_address() at least.

int __kernel_text_address(unsigned long addr)
{
	if (kernel_text_address(addr))
		return 1;
	...
	return 0;
}

int kernel_text_address(unsigned long addr)
{
	bool no_rcu;
	int ret = 1;
	...
	if (is_module_text_address(addr))
		goto out;
	...
	return ret;
}

bool is_module_text_address(unsigned long addr)
{
	guard(rcu)();
	return __module_text_address(addr) != NULL;
}

Furthermore, there are two checks of __kernel_text_address(), one is in
bt_address() and the other is after calling bt_address(), it looks like
redundant.

Handle the exception address first and then use __kernel_text_address()
to validate the calculated address for exception or the normal address
in bt_address(), then it can remove the check of __kernel_text_address()
after calling bt_address().

Just remove unnecessary checks, no functional changes intended.

Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
---
 arch/loongarch/kernel/unwind_orc.c | 16 +++++-----------
 1 file changed, 5 insertions(+), 11 deletions(-)

diff --git a/arch/loongarch/kernel/unwind_orc.c b/arch/loongarch/kernel/unwind_orc.c
index 9001b5377c22..5f256d75ab1e 100644
--- a/arch/loongarch/kernel/unwind_orc.c
+++ b/arch/loongarch/kernel/unwind_orc.c
@@ -351,12 +351,6 @@ static inline unsigned long bt_address(unsigned long ra)
 {
 	extern unsigned long eentry;
 
-	if (__kernel_text_address(ra))
-		return ra;
-
-	if (__module_text_address(ra))
-		return ra;
-
 	if (ra >= eentry && ra < eentry +  EXCCODE_INT_END * VECSIZE) {
 		unsigned long func;
 		unsigned long type = (ra - eentry) / VECSIZE;
@@ -374,10 +368,13 @@ static inline unsigned long bt_address(unsigned long ra)
 			break;
 		}
 
-		return func + offset;
+		ra = func + offset;
 	}
 
-	return ra;
+	if (__kernel_text_address(ra))
+		return ra;
+
+	return 0;
 }
 
 bool unwind_next_frame(struct unwind_state *state)
@@ -500,9 +497,6 @@ bool unwind_next_frame(struct unwind_state *state)
 		goto err;
 	}
 
-	if (!__kernel_text_address(state->pc))
-		goto err;
-
 	preempt_enable();
 	return true;
 
-- 
2.52.0


                 reply	other threads:[~2026-04-13  2:23 UTC|newest]

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