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From: Huacai Chen <chenhc@lemote.com>
To: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: linux-mips@vger.kernel.org, Fuxin Zhang <zhangfx@lemote.com>,
	Zhangjin Wu <wuzhangjin@gmail.com>,
	Huacai Chen <chenhuacai@gmail.com>,
	Jiaxun Yang <jiaxun.yang@flygoat.com>,
	Huacai Chen <chenhc@lemote.com>
Subject: [PATCH 2/2] MIPS: Loongson-3: Calculate ra properly when unwinding the stack
Date: Wed, 29 Apr 2020 17:38:41 +0800	[thread overview]
Message-ID: <1588153121-28507-2-git-send-email-chenhc@lemote.com> (raw)
In-Reply-To: <1588153121-28507-1-git-send-email-chenhc@lemote.com>

Loongson-3 has 16-bytes load/store instructions: gslq and gssq. This
patch calculate ra properly when unwinding the stack, if ra is saved
by gssq and restored by gslq.

Signed-off-by: Huacai Chen <chenhc@lemote.com>
---
 arch/mips/kernel/process.c | 16 +++++++++++++++-
 1 file changed, 15 insertions(+), 1 deletion(-)

diff --git a/arch/mips/kernel/process.c b/arch/mips/kernel/process.c
index b2a7975..be79218 100644
--- a/arch/mips/kernel/process.c
+++ b/arch/mips/kernel/process.c
@@ -279,7 +279,21 @@ static inline int is_ra_save_ins(union mips_instruction *ip, int *poff)
 		*poff = ip->i_format.simmediate / sizeof(ulong);
 		return 1;
 	}
-
+#ifdef CONFIG_CPU_LOONGSON64
+	if ((ip->loongson3_lswc2_format.opcode == swc2_op) &&
+		      (ip->loongson3_lswc2_format.ls == 1) &&
+		      (ip->loongson3_lswc2_format.fr == 0) &&
+		      (ip->loongson3_lswc2_format.base == 29)) {
+		if (ip->loongson3_lswc2_format.rt == 31) {
+			*poff = ip->loongson3_lswc2_format.offset << 1;
+			return 1;
+		}
+		if (ip->loongson3_lswc2_format.rq == 31) {
+			*poff = (ip->loongson3_lswc2_format.offset << 1) + 1;
+			return 1;
+		}
+	}
+#endif
 	return 0;
 #endif
 }
-- 
2.7.0


  reply	other threads:[~2020-04-29  9:39 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-04-29  9:38 [PATCH 1/2] MIPS: Loongson-3: Enable COP2 usage in kernel Huacai Chen
2020-04-29  9:38 ` Huacai Chen [this message]
2020-04-29 18:33 ` Thomas Bogendoerfer
2020-04-30  7:54   ` Huacai Chen
2020-05-01  0:44     ` Maciej W. Rozycki
2020-05-14  5:44       ` Huacai Chen

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