From: David Daney <[email protected]> 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. Cc: <[email protected]> Cc: Leonid Yegoshin <[email protected]> Signed-off-by: David Daney <[email protected]> --- This is the same patch sent 19/12/2014 with an improved changlog and Cc list. arch/mips/mm/tlb-r4k.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/arch/mips/mm/tlb-r4k.c b/arch/mips/mm/tlb-r4k.c index e90b2e8..30639a6 100644 --- 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); } -- 1.7.11.7 -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
