linux-kernel - [PATCH AUTOSEL 4.19 3/3] MIPS: Clear Cause.BD in instruction_pointer

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Date: Thu, 29 Feb 2024 10:51:37 -0500
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>,
	oleg@...hat.com,
	linux-mips@...r.kernel.org
Subject: [PATCH AUTOSEL 4.19 3/3] 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 b6578611dddbf..e45c082e12316 100644
--- a/arch/mips/include/asm/ptrace.h
+++ b/arch/mips/include/asm/ptrace.h
@@ -65,6 +65,7 @@ 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