MIPS: math-emu: Fix prefx detection and COP1X function field definition

When running applications which contain the instruction "prefx" on FPU-less
CPUs, a message "Illegal instruction" will be seen. This instruction is
supposed to be ignored by the FPU emulator. However, its current detection
and function field encoding are incorrect. This patch fix the issue.

Signed-off-by: Deng-Cheng Zhu <dengcheng.zhu@imgtec.com>
Reviewed-by: Leonid Yegoshin <Leonid.Yegoshin@imgtec.com>
Reviewed-by: Paul Burton <paul.burton@imgtec.com>
Acked-by: David Daney <david.daney@cavium.com>
Cc: linux-mips@linux-mips.org
Cc: Steven.Hill@imgtec.com
Patchwork: https://patchwork.linux-mips.org/patch/6608/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

diff --git a/arch/mips/include/uapi/asm/inst.h b/arch/mips/include/uapi/asm/inst.h
index b39ba25b41ccd2db0ae723ba01c4fab3a82621a6..f25181b19941db0544dc8e98187827343df99238 100644 (file)
--- a/arch/mips/include/uapi/asm/inst.h
+++ b/arch/mips/include/uapi/asm/inst.h
@@ -163,8 +163,8 @@ enum cop1_sdw_func {
  */
 enum cop1x_func {
        lwxc1_op     =  0x00, ldxc1_op     =  0x01,
-       pfetch_op    =  0x07, swxc1_op     =  0x08,
-       sdxc1_op     =  0x09, madd_s_op    =  0x20,
+       swxc1_op     =  0x08, sdxc1_op     =  0x09,
+       pfetch_op    =  0x0f, madd_s_op    =  0x20,
        madd_d_op    =  0x21, madd_e_op    =  0x22,
        msub_s_op    =  0x28, msub_d_op    =  0x29,
        msub_e_op    =  0x2a, nmadd_s_op   =  0x30,

diff --git a/arch/mips/math-emu/cp1emu.c b/arch/mips/math-emu/cp1emu.c
index 506925b2c3f366a12aecfb8ecc3cf6d69274654d..0b4e2e38294bf174132fcb4036cc958a370cfbec 100644 (file)
--- a/arch/mips/math-emu/cp1emu.c
+++ b/arch/mips/math-emu/cp1emu.c
@@ -1538,10 +1538,10 @@ static int fpux_emu(struct pt_regs *xcp, struct mips_fpu_struct *ctx,
                break;
        }
 
-       case 0x7:               /* 7 */
-               if (MIPSInst_FUNC(ir) != pfetch_op) {
+       case 0x3:
+               if (MIPSInst_FUNC(ir) != pfetch_op)
                        return SIGILL;
-               }
+
                /* ignore prefx operation */
                break;