3.16.51-rc1 review patch. If anyone has any objections, please let me know.
------------------ From: Matt Redfearn <[email protected]> commit cea8cd498f4f1c30ea27e3664b3c671e495c4fce upstream. 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 <[email protected]> Signed-off-by: Matt Redfearn <[email protected]> Reviewed-by: James Hogan <[email protected]> Cc: Marcin Nowakowski <[email protected]> Cc: Miodrag Dinic <[email protected]> Cc: Ingo Molnar <[email protected]> Cc: David Daney <[email protected]> Cc: [email protected] Cc: [email protected] Patchwork: https://patchwork.linux-mips.org/patch/16957/ Signed-off-by: Ralf Baechle <[email protected]> Signed-off-by: Ben Hutchings <[email protected]> --- arch/mips/include/uapi/asm/inst.h | 2 +- arch/mips/kernel/process.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) --- a/arch/mips/include/uapi/asm/inst.h +++ b/arch/mips/include/uapi/asm/inst.h @@ -808,7 +808,7 @@ struct mm16_r3_format { /* Load from gl 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 */ ;)))) }; --- a/arch/mips/kernel/process.c +++ b/arch/mips/kernel/process.c @@ -241,7 +241,7 @@ static inline int is_ra_save_ins(union m 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;
