3.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: David Daney <david.daney@xxxxxxxxxx> commit 9ead8632bbf454cfc709b6205dc9cd8582fb0d64 upstream. The following commits: 5890f70f15c52d (MIPS: Use dedicated exception handler if CPU supports RI/XI exceptions) 6575b1d4173eae (MIPS: kernel: cpu-probe: Detect unique RI/XI exceptions) break the kernel for *all* existing MIPS CPUs that implement the CP0_PageGrain[IEC] bit. They cause the TLB exception handlers to be generated without the legacy execute-inhibit handling, but never set the CP0_PageGrain[IEC] bit to activate the use of dedicated exception vectors for execute-inhibit exceptions. The result is that upon detection of an execute-inhibit violation, we loop forever in the TLB exception handlers instead of sending SIGSEGV to the task. If we are generating TLB exception handlers expecting separate vectors, we must also enable the CP0_PageGrain[IEC] feature. The bug was introduced in kernel version 3.17. Signed-off-by: David Daney <david.daney@xxxxxxxxxx> Cc: Leonid Yegoshin <Leonid.Yegoshin@xxxxxxxxxx> Cc: linux-mips@xxxxxxxxxxxxxx Patchwork: http://patchwork.linux-mips.org/patch/8880/ Signed-off-by: Ralf Baechle <ralf@xxxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- arch/mips/mm/tlb-r4k.c | 2 ++ 1 file changed, 2 insertions(+) --- a/arch/mips/mm/tlb-r4k.c +++ b/arch/mips/mm/tlb-r4k.c @@ -489,6 +489,8 @@ static void r4k_tlb_configure(void) #ifdef CONFIG_64BIT pg |= PG_ELPA; #endif + if (cpu_has_rixiex) + pg |= PG_IEC; write_c0_pagegrain(pg); }
