@@ -981,7 +981,7 @@ struct mm16_r3_format { /* Load from global pointer format */
struct mm16_r5_format { /* Load/store from stack pointer format */
__BITFIELD_FIELD(unsigned int opcode : 6,
__BITFIELD_FIELD(unsigned int rt : 5,
- __BITFIELD_FIELD(signed int simmediate : 5,
+ __BITFIELD_FIELD(unsigned int imm : 5,
__BITFIELD_FIELD(unsigned int : 16, /* Ignored */
;))))
};
@@ -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;
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 . 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 <> Signed-off-by: Matt Redfearn <> Reviewed-by: James Hogan <> --- Changes in v3: None Changes in v2: None arch/mips/include/uapi/asm/inst.h | 2 +- arch/mips/kernel/process.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-)