4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Will Deacon <will.dea...@arm.com>

commit 9b0de864b5bc upstream.

Since an mm has both a kernel and a user ASID, we need to ensure that
broadcast TLB maintenance targets both address spaces so that things
like CoW continue to work with the uaccess primitives in the kernel.

Reviewed-by: Mark Rutland <mark.rutl...@arm.com>
Tested-by: Laura Abbott <labb...@redhat.com>
Tested-by: Shanker Donthineni <shank...@codeaurora.org>
Signed-off-by: Will Deacon <will.dea...@arm.com>
Signed-off-by: Alex Shi <alex....@linaro.org> [v4.9 backport]
Signed-off-by: Mark Rutland <mark.rutl...@arm.com> [v4.9 backport]
Tested-by: Will Deacon <will.dea...@arm.com>
Tested-by: Greg Hackmann <ghackm...@google.com>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
 arch/arm64/include/asm/tlbflush.h |   16 ++++++++++++++--
 1 file changed, 14 insertions(+), 2 deletions(-)

--- a/arch/arm64/include/asm/tlbflush.h
+++ b/arch/arm64/include/asm/tlbflush.h
@@ -23,6 +23,7 @@
 
 #include <linux/sched.h>
 #include <asm/cputype.h>
+#include <asm/mmu.h>
 
 /*
  * Raw TLBI operations.
@@ -42,6 +43,11 @@
 
 #define __tlbi(op, ...)                __TLBI_N(op, ##__VA_ARGS__, 1, 0)
 
+#define __tlbi_user(op, arg) do {                                              
\
+       if (arm64_kernel_unmapped_at_el0())                                     
\
+               __tlbi(op, (arg) | USER_ASID_FLAG);                             
\
+} while (0)
+
 /*
  *     TLB Management
  *     ==============
@@ -103,6 +109,7 @@ static inline void flush_tlb_mm(struct m
 
        dsb(ishst);
        __tlbi(aside1is, asid);
+       __tlbi_user(aside1is, asid);
        dsb(ish);
 }
 
@@ -113,6 +120,7 @@ static inline void flush_tlb_page(struct
 
        dsb(ishst);
        __tlbi(vale1is, addr);
+       __tlbi_user(vale1is, addr);
        dsb(ish);
 }
 
@@ -139,10 +147,13 @@ static inline void __flush_tlb_range(str
 
        dsb(ishst);
        for (addr = start; addr < end; addr += 1 << (PAGE_SHIFT - 12)) {
-               if (last_level)
+               if (last_level) {
                        __tlbi(vale1is, addr);
-               else
+                       __tlbi_user(vale1is, addr);
+               } else {
                        __tlbi(vae1is, addr);
+                       __tlbi_user(vae1is, addr);
+               }
        }
        dsb(ish);
 }
@@ -182,6 +193,7 @@ static inline void __flush_tlb_pgtable(s
        unsigned long addr = uaddr >> 12 | (ASID(mm) << 48);
 
        __tlbi(vae1is, addr);
+       __tlbi_user(vae1is, addr);
        dsb(ish);
 }
 


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