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authorCatalin Marinas <catalin.marinas@arm.com>2014-04-22 19:14:29 +0400
committerRussell King <rmk+kernel@arm.linux.org.uk>2014-04-25 15:06:38 +0400
commit1417a6b8dc4db73055be9a3aa288b050e9dc06ab (patch)
tree82fe7a3cb59ff82ddb74a8ebc6ff2d2e9237733b /arch/arm/vfp
parentbc94081c6ac823c4723d8e36e9604c6cf3eba0ef (diff)
downloadlinux-1417a6b8dc4db73055be9a3aa288b050e9dc06ab.tar.xz
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 <catalin.marinas@arm.com> Tested-by: Arun KS <getarunks@gmail.com> Cc: Hartley Sweeten <hsweeten@visionengravers.com> Cc: Ryan Mallon <rmallon@gmail.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Diffstat (limited to 'arch/arm/vfp')
-rw-r--r--arch/arm/vfp/entry.S3
1 files changed, 1 insertions, 2 deletions
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