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authorMatt Redfearn <matt.redfearn@imgtec.com>2017-08-08 13:22:33 +0100
committerRalf Baechle <ralf@linux-mips.org>2017-09-06 13:20:25 +0200
commitcea8cd498f4f1c30ea27e3664b3c671e495c4fce (patch)
treef16e510564b485a6dffeab795cea7b103b34f7ce /arch/mips/kernel
parenta0ae2b08331a9882150618e0c81ea837e4a37ace (diff)
MIPS: microMIPS: Fix decoding of swsp16 instruction
When the immediate encoded in the instruction is accessed, it is sign extended due to being a signed value being assigned to a signed integer. The ISA specifies that this operation is an unsigned operation. The sign extension leads us to incorrectly decode: 801e9c8e: cbf1 sw ra,68(sp) As having an immediate of 1073741809. Since the instruction format does not specify signed/unsigned, and this is currently the only location to use this instuction format, change it to an unsigned immediate. Fixes: bb9bc4689b9c ("MIPS: Calculate microMIPS ra properly when unwinding the stack") Suggested-by: Paul Burton <paul.burton@imgtec.com> Signed-off-by: Matt Redfearn <matt.redfearn@imgtec.com> Reviewed-by: James Hogan <james.hogan@imgtec.com> Cc: Marcin Nowakowski <marcin.nowakowski@imgtec.com> Cc: Miodrag Dinic <miodrag.dinic@imgtec.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: David Daney <david.daney@cavium.com> Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/16957/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Diffstat (limited to 'arch/mips/kernel')
-rw-r--r--arch/mips/kernel/process.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/mips/kernel/process.c b/arch/mips/kernel/process.c
index 516089f8c6e7..debc0410a2d5 100644
--- a/arch/mips/kernel/process.c
+++ b/arch/mips/kernel/process.c
@@ -214,7 +214,7 @@ static inline int is_ra_save_ins(union mips_instruction *ip, int *poff)
if (ip->mm16_r5_format.rt != 31)
return 0;
- *poff = ip->mm16_r5_format.simmediate;
+ *poff = ip->mm16_r5_format.imm;
*poff = (*poff << 2) / sizeof(ulong);
return 1;