From mboxrd@z Thu Jan 1 00:00:00 1970 From: linus.walleij@linaro.org (Linus Walleij) Date: Mon, 11 Jul 2016 19:08:13 +0200 Subject: [PATCH] RFC: ARM: fix the uaccess crash on PB11MPCore Message-ID: <1468256893-12811-1-git-send-email-linus.walleij@linaro.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org 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. I also know that Oxnas has actual, mass-deployed NAS (PogoPlug Pro variants) using PB11MPCore, and that they may or may not be seeing the same issue so I want their feedback on this: do you or do you not see this with mainline, or have you not even tested? Cc: Russell King Cc: Will Deacon Cc: Neil Armstrong Fixes: a5e090acbf54 ("ARM: software-based priviledged-no-access support") Signed-off-by: Linus Walleij --- arch/arm/kernel/smp_tlb.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/arch/arm/kernel/smp_tlb.c b/arch/arm/kernel/smp_tlb.c index 2e72be4f623e..7cb079e74010 100644 --- a/arch/arm/kernel/smp_tlb.c +++ b/arch/arm/kernel/smp_tlb.c @@ -9,6 +9,7 @@ */ #include #include +#include #include #include @@ -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) -- 2.7.4