Commit 51061b88 authored Mar 06, 2014 by Deng-Cheng Zhu Committed by Ralf Baechle Mar 11, 2014

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>

parent 031365b4

arch/mips/include/uapi/asm/inst.h

+2 −2

Original line number	Diff line number	Diff line
		@@ -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,

arch/mips/math-emu/cp1emu.c

+3 −3

Original line number	Diff line number	Diff line
		@@ -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;

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