Re: [PATCH v4 5/5] powerpc/lib/sstep: Add isel instruction emulation
From: Cyril Bur <hidden>
Date: 2017-07-31 04:11:35
On Mon, 2017-07-31 at 10:58 +1000, Matt Brown wrote:
This adds emulation for the isel instruction. Tested for correctness against the isel instruction and its extended mnemonics (lt, gt, eq) on ppc64le. Signed-off-by: Matt Brown <redacted>
Reviewed-by: Cyril Bur <redacted>
quoted hunk ↗ jump to hunk
--- v4: - simplify if statement to ternary op (same as isel emulation in kernel/traps.c) v2: - fixed opcode - fixed definition to include the 'if RA=0, a=0' clause - fixed ccr bitshifting error --- arch/powerpc/lib/sstep.c | 8 ++++++++ 1 file changed, 8 insertions(+)diff --git a/arch/powerpc/lib/sstep.c b/arch/powerpc/lib/sstep.c index af4eef9..473bab5 100644 --- a/arch/powerpc/lib/sstep.c +++ b/arch/powerpc/lib/sstep.c@@ -1240,6 +1240,14 @@ int analyse_instr(struct instruction_op *op, struct pt_regs *regs, /* * Logical instructions */ + case 15: /* isel */ + mb = (instr >> 6) & 0x1f; /* bc */ + val = (regs->ccr >> (31 - mb)) & 1; + val2 = (ra) ? regs->gpr[ra] : 0; + + regs->gpr[rd] = (val) ? val2 : regs->gpr[rb]; + goto logical_done; + case 26: /* cntlzw */ asm("cntlzw %0,%1" : "=r" (regs->gpr[ra]) : "r" (regs->gpr[rd]));