From 1417a6b8dc4db73055be9a3aa288b050e9dc06ab Mon Sep 17 00:00:00 2001 From: Catalin Marinas Date: Tue, 22 Apr 2014 16:14:29 +0100 Subject: ARM: 8036/1: Enable IRQs before attempting to read user space in __und_usr The Undef abort handler in the kernel reads the undefined instruction from user space. If the page table was modified from another CPU, the user access could fail and do_page_fault() will be executed with interrupts disabled. This can potentially deadlock on ARM11MPCore or on Cortex-A15 with erratum 798181 workaround enabled (both implying IPI for TLB maintenance with page table lock held). This patch enables the IRQs in __und_usr before attempting to read the instruction from user space. Signed-off-by: Catalin Marinas Tested-by: Arun KS Cc: Hartley Sweeten Cc: Ryan Mallon Signed-off-by: Russell King --- arch/arm/vfp/entry.S | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) (limited to 'arch/arm/vfp') diff --git a/arch/arm/vfp/entry.S b/arch/arm/vfp/entry.S index f0759e70fb86..fe6ca574d093 100644 --- a/arch/arm/vfp/entry.S +++ b/arch/arm/vfp/entry.S @@ -22,11 +22,10 @@ @ r9 = normal "successful" return address @ r10 = this threads thread_info structure @ lr = unrecognised instruction return address -@ IRQs disabled. +@ IRQs enabled. @ ENTRY(do_vfp) inc_preempt_count r10, r4 - enable_irq ldr r4, .LCvfp ldr r11, [r10, #TI_CPU] @ CPU number add r10, r10, #TI_VFPSTATE @ r10 = workspace -- cgit v1.2.1