[PATCH v2 09/18] arm64: mm: Invalidate both kernel and user ASIDs when performing TLBI

[Will Deacon]

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.

Signed-off-by: Will Deacon <will.dea...@arm.com>
---
 arch/arm64/include/asm/tlbflush.h | 16 ++++++++++++++--
 1 file changed, 14 insertions(+), 2 deletions(-)

diff --git a/arch/arm64/include/asm/tlbflush.h 
b/arch/arm64/include/asm/tlbflush.h
index af1c76981911..9e82dd79c7db 100644
--- 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.
@@ -54,6 +55,11 @@
 
 #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
  *     ==============
@@ -115,6 +121,7 @@ static inline void flush_tlb_mm(struct mm_struct *mm)
 
        dsb(ishst);
        __tlbi(aside1is, asid);
+       __tlbi_user(aside1is, asid);
        dsb(ish);
 }
 
@@ -125,6 +132,7 @@ static inline void flush_tlb_page(struct vm_area_struct 
*vma,
 
        dsb(ishst);
        __tlbi(vale1is, addr);
+       __tlbi_user(vale1is, addr);
        dsb(ish);
 }
 
@@ -151,10 +159,13 @@ static inline void __flush_tlb_range(struct 
vm_area_struct *vma,
 
        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);
 }
@@ -194,6 +205,7 @@ static inline void __flush_tlb_pgtable(struct mm_struct *mm,
        unsigned long addr = uaddr >> 12 | (ASID(mm) << 48);
 
        __tlbi(vae1is, addr);
+       __tlbi_user(vae1is, addr);
        dsb(ish);
 }
 
-- 
2.1.4