MIPS: Send SIGILL for R6 branches in `__compute_return_epc_for_insn' (a60b1a5b) · Commits · 戴 / test

Fix: * commit ("MIPS: Emulate the new MIPS R6 branch compact (BC) instruction"), * commit ("MIPS: Emulate the new MIPS R6 BALC instruction"), * commit ("MIPS: Emulate the new MIPS R6 BEQZC and JIC instructions"), * commit ("MIPS: Emulate the new MIPS R6 BNEZC and JIALC instructions"), * commit ("MIPS: Emulate the new MIPS R6 BOVC, BEQC and BEQZALC instructions") and send SIGILL rather than returning -SIGILL for R6 branch and jump instructions. Returning -SIGILL is never correct as the API defines this function's result upon error to be -EFAULT and a signal actually issued. Fixes: ("MIPS: Emulate the new MIPS R6 branch compact (BC) instruction") Fixes: ("MIPS: Emulate the new MIPS R6 BALC instruction") Fixes: ("MIPS: Emulate the new MIPS R6 BEQZC and JIC instructions") Fixes: ("MIPS: Emulate the new MIPS R6 BNEZC and JIALC instructions") Fixes: ("MIPS: Emulate the new MIPS R6 BOVC, BEQC and BEQZALC instructions") Signed-off-by:

Maciej W. Rozycki <macro@imgtec.com> Cc: James Hogan <james.hogan@imgtec.com> Cc: linux-mips@linux-mips.org Cc: stable@vger.kernel.org # 3.19+ Patchwork: https://patchwork.linux-mips.org/patch/16399/ Signed-off-by:

Ralf Baechle <ralf@linux-mips.org>

arch/mips/kernel/branch.c

+15 −20

Original line number	Diff line number	Diff line
		@@ -771,35 +771,27 @@ int __compute_return_epc_for_insn(struct pt_regs *regs,
		#else
		case bc6_op:
		/* Only valid for MIPS R6 */
		if (!cpu_has_mips_r6) {
		ret = -SIGILL;
		break;
		}
		if (!cpu_has_mips_r6)
		goto sigill_r6;
		regs->cp0_epc += 8;
		break;
		case balc6_op:
		if (!cpu_has_mips_r6) {
		ret = -SIGILL;
		break;
		}
		if (!cpu_has_mips_r6)
		goto sigill_r6;
		/* Compact branch: BALC */
		regs->regs[31] = epc + 4;
		epc += 4 + (insn.i_format.simmediate << 2);
		regs->cp0_epc = epc;
		break;
		case pop66_op:
		if (!cpu_has_mips_r6) {
		ret = -SIGILL;
		break;
		}
		if (!cpu_has_mips_r6)
		goto sigill_r6;
		/* Compact branch: BEQZC \|\| JIC */
		regs->cp0_epc += 8;
		break;
		case pop76_op:
		if (!cpu_has_mips_r6) {
		ret = -SIGILL;
		break;
		}
		if (!cpu_has_mips_r6)
		goto sigill_r6;
		/* Compact branch: BNEZC \|\| JIALC */
		if (!insn.i_format.rs) {
		/* JIALC: set $31/ra */
		@@ -811,10 +803,8 @@ int __compute_return_epc_for_insn(struct pt_regs *regs,
		case pop10_op:
		case pop30_op:
		/* Only valid for MIPS R6 */
		if (!cpu_has_mips_r6) {
		ret = -SIGILL;
		break;
		}
		if (!cpu_has_mips_r6)
		goto sigill_r6;
		/*
		* Compact branches:
		* bovc, beqc, beqzalc, bnvc, bnec, bnezlac
		@@ -837,6 +827,11 @@ sigill_r2r6:
		current->comm);
		force_sig(SIGILL, current);
		return -EFAULT;
		sigill_r6:
		pr_info("%s: R6 branch but no MIPSr6 ISA support - sending SIGILL.\n",
		current->comm);
		force_sig(SIGILL, current);
		return -EFAULT;
		}
		EXPORT_SYMBOL_GPL(__compute_return_epc_for_insn);

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