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@xxxxxxxxxxxxxxx # 2.6.14+
Fixes: e50c0a8fa60d ("Support the MIPS32 / MIPS64 DSP ASE.")
Signed-off-by: Maciej W. Rozycki <macro@xxxxxxxxxx>
---
I hope folding the formatting fix and `pr_info' update with the base
change is fine given that they all apply to the same code line.
Maciej
linux-mips-epc-for-insn-sigill-dsp.diff
Index: linux-sfr-test/arch/mips/kernel/branch.c
===================================================================
--- linux-sfr-test.orig/arch/mips/kernel/branch.c 2017-06-01 06:30:07.969735000 +0100
+++ linux-sfr-test/arch/mips/kernel/branch.c 2017-06-01 06:33:27.149519000 +0100
@@ -399,7 +399,7 @@ 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.
*
@@ -830,8 +830,9 @@ int __compute_return_epc_for_insn(struct
return ret;
sigill_dsp:
- 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;
sigill_r6:
pr_info("%s: R2 branch but r2-to-r6 emulator is not preset - sending SIGILL.\n",
