Patch "MIPS: Send SIGILL for linked branches in `__compute_return_epc_for_insn'" has been added to the 4.9-stable tree

This is a note to let you know that I've just added the patch titled

MIPS: Send SIGILL for linked branches in `__compute_return_epc_for_insn'

to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
mips-send-sigill-for-linked-branches-in-__compute_return_epc_for_insn.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: "Maciej W. Rozycki" <[email protected]>
Date: Fri, 16 Jun 2017 00:12:53 +0100
Subject: MIPS: Send SIGILL for linked branches in `__compute_return_epc_for_insn'

From: Maciej W. Rozycki <[email protected]>

commit fef40be6da856afead4177aaa9d869a66fb3381f upstream.

Fix commit 319824eabc3f ("MIPS: kernel: branch: Do not emulate the branch likelies on MIPS R6") and also send SIGILL rather than returning -SIGILL for BLTZAL, BLTZALL, BGEZAL and BGEZALL instruction encodings no longer supported in R6, except where emulated. Returning -SIGILL is never correct as the API defines this function's result upon error to be -EFAULT and a signal actually issued.

Patchwork: https://patchwork.linux-mips.org/patch/16398/

---
 arch/mips/kernel/branch.c |   12 ++++--------
 1 file changed, 4 insertions(+), 8 deletions(-)

@@ -473,10 +473,8 @@ int __compute_return_epc_for_insn(struct
 		case bltzal_op:
 		case bltzall_op:
 			if (NO_R6EMU && (insn.i_format.rs ||
-			    insn.i_format.rt == bltzall_op)) {
-				ret = -SIGILL;
-				break;
-			}
+			    insn.i_format.rt == bltzall_op))
+				goto sigill_r2r6;
 			regs->regs[31] = epc + 8;
 			/*
 			 * OK we are here either because we hit a NAL

@@ -507,10 +505,8 @@ int __compute_return_epc_for_insn(struct
 		case bgezal_op:
 		case bgezall_op:
 			if (NO_R6EMU && (insn.i_format.rs ||
-			    insn.i_format.rt == bgezall_op)) {
-				ret = -SIGILL;
-				break;
-			}
+			    insn.i_format.rt == bgezall_op))
+				goto sigill_r2r6;
 			regs->regs[31] = epc + 8;
 			/*
 			 * OK we are here either because we hit a BAL

Patches currently in stable-queue which might be from [email protected] are

queue-4.9/mips-send-sigill-for-bposge32-in-__compute_return_epc_for_insn.patch queue-4.9/mips-actually-decode-jalx-in-__compute_return_epc_for_insn.patch queue-4.9/mips-fix-a-typo-s-preset-present-in-r2-to-r6-emulation-error-message.patch queue-4.9/mips-fix-unaligned-pc-interpretation-in-compute_return_epc.patch queue-4.9/mips-rename-sigill_r6-to-sigill_r2r6-in-__compute_return_epc_for_insn.patch queue-4.9/mips-send-sigill-for-r6-branches-in-__compute_return_epc_for_insn.patch queue-4.9/mips-send-sigill-for-linked-branches-in-__compute_return_epc_for_insn.patch queue-4.9/mips-math-emu-prevent-wrong-isa-mode-instruction-emulation.patch