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Commit 5f9f41c4 authored by Markos Chandras's avatar Markos Chandras
Browse files

MIPS: kernel: Prepare the JR instruction for emulation on MIPS R6 



The MIPS R6 JR instruction is an alias to the JALR one, so it may
need emulation for non-R6 userlands.

Signed-off-by: default avatarMarkos Chandras <markos.chandras@imgtec.com>
parent b5ad2c21

arch/mips/include/asm/branch.h

+3 −0
Original line number Original line Diff line number Diff line
@@ -13,6 +13,9 @@ 
#include <asm/ptrace.h>

#include <asm/ptrace.h>

#include <asm/inst.h>

#include <asm/inst.h>





static int mipsr2_emulation = 0;

#define NO_R6EMU	(cpu_has_mips_r6 && !mipsr2_emulation)



extern int __isa_exception_epc(struct pt_regs *regs);

extern int __isa_exception_epc(struct pt_regs *regs);

extern int __compute_return_epc(struct pt_regs *regs);

extern int __compute_return_epc(struct pt_regs *regs);

extern int __compute_return_epc_for_insn(struct pt_regs *regs,

extern int __compute_return_epc_for_insn(struct pt_regs *regs,

arch/mips/kernel/branch.c

+9 −2
Original line number Original line Diff line number Diff line
@@ -417,6 +417,8 @@ int __compute_return_epc_for_insn(struct pt_regs *regs, 
			regs->regs[insn.r_format.rd] = epc + 8;

			regs->regs[insn.r_format.rd] = epc + 8;

			/* Fall through */

			/* Fall through */

		case jr_op:

		case jr_op:

			if (NO_R6EMU && insn.r_format.func == jr_op)

				goto sigill_r6;

			regs->cp0_epc = regs->regs[insn.r_format.rs];

			regs->cp0_epc = regs->regs[insn.r_format.rs];

			break;

			break;

		}

		}
@@ -477,7 +479,7 @@ int __compute_return_epc_for_insn(struct pt_regs *regs, 




		case bposge32_op:

		case bposge32_op:

			if (!cpu_has_dsp)

			if (!cpu_has_dsp)

				goto sigill;

				goto sigill_dsp;





			dspcontrol = rddsp(0x01);

			dspcontrol = rddsp(0x01);
@@ -631,10 +633,15 @@ int __compute_return_epc_for_insn(struct pt_regs *regs, 




	return ret;

	return ret;





sigill:

sigill_dsp:

	printk("%s: DSP branch but not DSP ASE - sending SIGBUS.\n", current->comm);

	printk("%s: DSP branch but not DSP ASE - sending SIGBUS.\n", current->comm);

	force_sig(SIGBUS, current);

	force_sig(SIGBUS, current);

	return -EFAULT;

	return -EFAULT;

sigill_r6:

	pr_info("%s: R2 branch but r2-to-r6 emulator is not preset - sending SIGILL.\n",

		current->comm);

	force_sig(SIGILL, current);

	return -EFAULT;

}

}

EXPORT_SYMBOL_GPL(__compute_return_epc_for_insn);

EXPORT_SYMBOL_GPL(__compute_return_epc_for_insn);

arch/mips/math-emu/cp1emu.c

+3 −0
Original line number Original line Diff line number Diff line
@@ -448,6 +448,9 @@ static int isBranchInstr(struct pt_regs *regs, struct mm_decoded_insn dec_insn, 
				dec_insn.next_pc_inc;

				dec_insn.next_pc_inc;

			/* Fall through */

			/* Fall through */

		case jr_op:

		case jr_op:

			/* For R6, JR already emulated in jalr_op */

			if (NO_R6EMU && insn.r_format.opcode == jr_op)

				break;

			*contpc = regs->regs[insn.r_format.rs];

			*contpc = regs->regs[insn.r_format.rs];

			return 1;

			return 1;

		}

		}