linux-kernel - [PATCH 5.4 006/183] MIPS: Clear Cause.BD in instruction_pointer

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Message-ID: <20240324234638.1355609-7-sashal@kernel.org>
Date: Sun, 24 Mar 2024 19:43:39 -0400
From: Sasha Levin <sashal@...nel.org>
To: linux-kernel@...r.kernel.org,
	stable@...r.kernel.org
Cc: Jiaxun Yang <jiaxun.yang@...goat.com>,
	Thomas Bogendoerfer <tsbogend@...ha.franken.de>,
	Sasha Levin <sashal@...nel.org>
Subject: [PATCH 5.4 006/183] MIPS: Clear Cause.BD in instruction_pointer_set

From: Jiaxun Yang <jiaxun.yang@...goat.com>

[ Upstream commit 9d6e21ddf20293b3880ae55b9d14de91c5891c59 ]

Clear Cause.BD after we use instruction_pointer_set to override
EPC.

This can prevent exception_epc check against instruction code at
new return address.
It won't be considered as "in delay slot" after epc being overridden
anyway.

Signed-off-by: Jiaxun Yang <jiaxun.yang@...goat.com>
Signed-off-by: Thomas Bogendoerfer <tsbogend@...ha.franken.de>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 arch/mips/include/asm/ptrace.h | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/mips/include/asm/ptrace.h b/arch/mips/include/asm/ptrace.h
index 1e76774b36ddf..2849a9b65a055 100644
--- a/arch/mips/include/asm/ptrace.h
+++ b/arch/mips/include/asm/ptrace.h
@@ -60,6 +60,7 @@ static inline void instruction_pointer_set(struct pt_regs *regs,
                                            unsigned long val)
 {
 	regs->cp0_epc = val;
+	regs->cp0_cause &= ~CAUSEF_BD;
 }
 
 /* Query offset/name of register from its name/offset */
-- 
2.43.0