[Xen-changelog] [xen stable-4.4] xen: arm: flush TLB after overwriting 1:1 mapping in boot page tables

[patchbot@xxxxxxx]

commit 7adf0b22d888bd0514d153c8b44e4982ad4d6e6e
Author:     Ian Campbell <ian.campbell@xxxxxxxxxx>
AuthorDate: Mon Jul 14 17:39:10 2014 +0100
Commit:     Ian Campbell <ian.campbell@xxxxxxxxxx>
CommitDate: Wed Jul 23 09:50:33 2014 +0100

    xen: arm: flush TLB after overwriting 1:1 mapping in boot page tables
    
    Otherwise a stale TLB entry can shadow the fixmap/UART or DTB mapping
    
    Signed-off-by: Ian Campbell <ian.campbell@xxxxxxxxxx>
    Acked-by: Julien Grall <julien.grall@xxxxxxxxxx>
    (cherry picked from commit f1870804e58565399cd770e93f62e7ce57cd5231)
---
 xen/arch/arm/arm32/head.S |   13 ++++++++++++-
 xen/arch/arm/arm64/head.S |   13 ++++++++++++-
 2 files changed, 24 insertions(+), 2 deletions(-)

diff --git a/xen/arch/arm/arm32/head.S b/xen/arch/arm/arm32/head.S
index 96230ac..5bc23cc 100644
--- a/xen/arch/arm/arm32/head.S
+++ b/xen/arch/arm/arm32/head.S
@@ -372,9 +372,20 @@ paging:
         ldr   r4, =BOOT_FDT_VIRT_START
         mov   r4, r4, lsr #18        /* Slot for BOOT_FDT_VIRT_START */
         strd  r2, r3, [r1, r4]       /* Map it in the early fdt slot */
-        dsb
 1:
 
+        /*
+         * Flush the TLB in case the 1:1 mapping happens to clash with
+         * the virtual addresses used by the fixmap or DTB.
+         */
+        dsb                          /* Ensure any page table updates made 
above
+                                      * have occurred. */
+
+        isb
+        mcr   CP32(r0, TLBIALLH)     /* Flush hypervisor TLB */
+        dsb                          /* Ensure completion of TLB flush */
+        isb
+
         PRINT("- Ready -\r\n")
 
         /* The boot CPU should go straight into C now */
diff --git a/xen/arch/arm/arm64/head.S b/xen/arch/arm/arm64/head.S
index 31afdd0..be44f67 100644
--- a/xen/arch/arm/arm64/head.S
+++ b/xen/arch/arm/arm64/head.S
@@ -382,9 +382,20 @@ paging:
         ldr   x1, =BOOT_FDT_VIRT_START
         lsr   x1, x1, #18            /* x4 := Slot for BOOT_FDT_VIRT_START */
         str   x2, [x4, x1]           /* Map it in the early fdt slot */
-        dsb   sy
 1:
 
+        /*
+         * Flush the TLB in case the 1:1 mapping happens to clash with
+         * the virtual addresses used by the fixmap or DTB.
+         */
+        dsb   sy                     /* Ensure any page table updates made 
above
+                                      * have occurred. */
+
+        isb
+        tlbi  alle2
+        dsb   sy                     /* Ensure completion of TLB flush */
+        isb
+
         PRINT("- Ready -\r\n")
 
         /* The boot CPU should go straight into C now */
--
generated by git-patchbot for /home/xen/git/xen.git#stable-4.4

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