[PATCH 3.2 22/74] MIPS: Send SIGILL for BPOSGE32 in `__compute_return_epc_for_insn'

[Ben Hutchings]

3.2.94-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: "Maciej W. Rozycki" <macro@xxxxxxxxxx>

commit 7b82c1058ac1f8f8b9f2b8786b1f710a57a870a8 upstream.

Fix commit e50c0a8fa60d ("Support the MIPS32 / MIPS64 DSP ASE.") and
send SIGILL rather than SIGBUS whenever an unimplemented BPOSGE32 DSP
ASE instruction has been encountered in `__compute_return_epc_for_insn'
as our Reserved Instruction exception handler would in response to an
attempt to actually execute the instruction.  Sending SIGBUS only makes
sense for the unaligned PC case, since moved to `__compute_return_epc'.
Adjust function documentation accordingly, correct formatting and use
`pr_info' rather than `printk' as the other exit path already does.

Fixes: e50c0a8fa60d ("Support the MIPS32 / MIPS64 DSP ASE.")
Signed-off-by: Maciej W. Rozycki <macro@xxxxxxxxxx>
Cc: James Hogan <james.hogan@xxxxxxxxxx>
Cc: linux-mips@xxxxxxxxxxxxxx
Patchwork: https://patchwork.linux-mips.org/patch/16396/
Signed-off-by: Ralf Baechle <ralf@xxxxxxxxxxxxxx>
[bwh: Backported to 3.2:
 - Drop the comment change
 - Adjust context]
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
--- a/arch/mips/kernel/branch.c
+++ b/arch/mips/kernel/branch.c
@@ -247,7 +247,8 @@ unaligned:
 	return -EFAULT;
 
 sigill:
-	printk("%s: DSP branch but not DSP ASE - sending SIGBUS.\n", current->comm);
-	force_sig(SIGBUS, current);
+	pr_info("%s: DSP branch but not DSP ASE - sending SIGILL.\n",
+		current->comm);
+	force_sig(SIGILL, current);
 	return -EFAULT;
 }