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[V7,3/3] MIPS: Loongson-3: Calculate ra properly when unwinding the stack

Message ID 1600679548-29154-3-git-send-email-chenhc@lemote.com (mailing list archive)
State Accepted
Commit bc1c969f1158485f64e360659f755d19136bb5b0
Headers show
Series [V7,1/3] MIPS: context switch: Use save/restore instead of set/clear for Status.CU2 | expand

Commit Message

Huacai Chen Sept. 21, 2020, 9:12 a.m. UTC 
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(-)
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Patch

diff --git a/arch/mips/kernel/process.c b/arch/mips/kernel/process.c
index b36297e..37f05c8 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
 }