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MIPS: Send SIGILL for linked branches in `__compute_return_epc_for_insn' 

Fix commit 319824eabc ("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.

Fixes: 319824eabc ("MIPS: kernel: branch: Do not emulate the branch likelies on MIPS R6")
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/16398/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
This commit is contained in:
Maciej W. Rozycki 2017-06-16 00:12:53 +01:00 committed by Ralf Baechle
parent 1f4edde422
commit fef40be6da
1 changed files with 4 additions and 8 deletions
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12
arch/mips/kernel/branch.c
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@ -473,10 +473,8 @@ int __compute_return_epc_for_insn(struct pt_regs *regs,
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 pt_regs *regs,
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