[PATCH 3.18] MIPS: Send SIGILL for BPOSGE32 in `__compute_return_epc_for_insn'

[PATCH 3.18] MIPS: Send SIGILL for BPOSGE32 in `__compute_return_epc_for_insn'

[Maciej W. Rozycki]

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.

Cc: stable@vger.kernel.org # 2.6.14+
Fixes: e50c0a8fa60d ("Support the MIPS32 / MIPS64 DSP ASE.")
Signed-off-by: Maciej W. Rozycki <macro@imgtec.com>
---
Hi,

 This is a (mechanically regenerated) version of commit 7b82c1058ac1 for 
3.18-stable and before.  No functional changes.  Please apply.

  Maciej

linux-mips-epc-for-insn-sigill-dsp.diff
---
 arch/mips/kernel/branch.c |    7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

Index: linux/arch/mips/kernel/branch.c
===================================================================
--- linux.orig/arch/mips/kernel/branch.c
+++ linux/arch/mips/kernel/branch.c
@@ -396,7 +396,7 @@ int __MIPS16e_compute_return_epc(struct 
  *
  * @regs:	Pointer to pt_regs
  * @insn:	branch instruction to decode
- * @returns:	-EFAULT on error and forces SIGBUS, and on success
+ * @returns:	-EFAULT on error and forces SIGILL, and on success
  *		returns 0 or BRANCH_LIKELY_TAKEN as appropriate after
  *		evaluating the branch.
  */
@@ -632,8 +632,9 @@ int __compute_return_epc_for_insn(struct
 	return ret;
 
 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;
 }
 EXPORT_SYMBOL_GPL(__compute_return_epc_for_insn);

Re: [PATCH 3.18] MIPS: Send SIGILL for BPOSGE32 in `__compute_return_epc_for_insn'

[Greg KH]

On Tue, Jul 25, 2017 at 08:07:13PM +0100, Maciej W. Rozycki wrote:
> 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.
> 
> Cc: stable@vger.kernel.org # 2.6.14+
> Fixes: e50c0a8fa60d ("Support the MIPS32 / MIPS64 DSP ASE.")
> Signed-off-by: Maciej W. Rozycki <macro@imgtec.com>
> ---
> Hi,
> 
>  This is a (mechanically regenerated) version of commit 7b82c1058ac1 for 
> 3.18-stable and before.  No functional changes.  Please apply.

Thanks, now queued up.

greg k-h