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ARM: fix the uaccess crash on PB11MPCore

Message ID 1473687521-779-1-git-send-email-linus.walleij@linaro.org
State Accepted
Commit 90f92c631b210c1e97080b53a9d863783281a932
Headers show

Commit Message

Linus Walleij Sept. 12, 2016, 1:38 p.m. UTC 
The following patch was sketched by Russell in response to my
crashes on the PB11MPCore after the patch for software-based
priviledged no access support for ARMv8.1. See this thread:
http://marc.info/?l=linux-arm-kernel&m=144051749807214&w=2

I am unsure what is going on, I suspect everyone involved in
the discussion is. I just want to repost this to get the
discussion restarted, as I still have to apply this patch
with every kernel iteration to get my PB11MPCore Realview
running.

Testing by Neil Armstrong on the Oxnas NAS has revealed that
this bug exist also on that widely deployed hardware, so
we are probably currently regressing all ARM11MPCore systems.

Cc: Russell King <linux@armlinux.org.uk>
Cc: Will Deacon <will.deacon@arm.com>
Fixes: a5e090acbf54 ("ARM: software-based priviledged-no-access support")
Tested-by: Neil Armstrong <narmstrong@baylibre.com>

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

---
 arch/arm/kernel/smp_tlb.c | 7 +++++++
 1 file changed, 7 insertions(+)

-- 
2.7.4


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diff mbox

Patch

diff --git a/arch/arm/kernel/smp_tlb.c b/arch/arm/kernel/smp_tlb.c
index 22313cb53362..9af0701f7094 100644
--- a/arch/arm/kernel/smp_tlb.c
+++ b/arch/arm/kernel/smp_tlb.c
@@ -9,6 +9,7 @@ 
  */
 #include <linux/preempt.h>
 #include <linux/smp.h>
+#include <linux/uaccess.h>
 
 #include <asm/smp_plat.h>
 #include <asm/tlbflush.h>
@@ -40,8 +41,11 @@  static inline void ipi_flush_tlb_mm(void *arg)
 static inline void ipi_flush_tlb_page(void *arg)
 {
 	struct tlb_args *ta = (struct tlb_args *)arg;
+	unsigned int __ua_flags = uaccess_save_and_enable();
 
 	local_flush_tlb_page(ta->ta_vma, ta->ta_start);
+
+	uaccess_restore(__ua_flags);
 }
 
 static inline void ipi_flush_tlb_kernel_page(void *arg)
@@ -54,8 +58,11 @@  static inline void ipi_flush_tlb_kernel_page(void *arg)
 static inline void ipi_flush_tlb_range(void *arg)
 {
 	struct tlb_args *ta = (struct tlb_args *)arg;
+	unsigned int __ua_flags = uaccess_save_and_enable();
 
 	local_flush_tlb_range(ta->ta_vma, ta->ta_start, ta->ta_end);
+
+	uaccess_restore(__ua_flags);
 }
 
 static inline void ipi_flush_tlb_kernel_range(void *arg)