On 16/09/2023 05:06, Henry Wang wrote:
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Some addressed comments on enable_boot_cpu_mm() were reintroduced
back during the code movement from arm64/head.S to arm64/mmu/head.S.
We should drop the unreachable code, move the 'mov lr, x5' closer to
'b remove_identity_mapping' so it is clearer that it will return,
and update the in-code comment accordingly.

Fixes: 6734327d76be ("xen/arm64: Split and move MMU-specific head.S to 
mmu/head.S")
Reported-by: Julien Grall <[email protected]>
Signed-off-by: Henry Wang <[email protected]>
Reviewed-by: Ayan Kumar Halder <[email protected]>
---
  xen/arch/arm/arm64/mmu/head.S | 11 +++--------
  1 file changed, 3 insertions(+), 8 deletions(-)

diff --git a/xen/arch/arm/arm64/mmu/head.S b/xen/arch/arm/arm64/mmu/head.S
index a5271e3880..88075ef083 100644
--- a/xen/arch/arm/arm64/mmu/head.S
+++ b/xen/arch/arm/arm64/mmu/head.S
@@ -329,7 +329,6 @@ ENTRY(enable_boot_cpu_mm)
          load_paddr x0, boot_pgtable

          bl    enable_mmu
-        mov   lr, x5

          /*
           * The MMU is turned on and we are in the 1:1 mapping. Switch
@@ -338,19 +337,15 @@ ENTRY(enable_boot_cpu_mm)
          ldr   x0, =1f
          br    x0
  1:
+        mov   lr, x5
          /*
           * The 1:1 map may clash with other parts of the Xen virtual memory
           * layout. As it is not used anymore, remove it completely to
           * avoid having to worry about replacing existing mapping
-         * afterwards. Function will return to primary_switched.
+         * afterwards. Function will return to the virtual address requested
+         * by the caller.
           */
          b     remove_identity_mapping
-
-        /*
-         * Below is supposed to be unreachable code, as "ret" in
-         * remove_identity_mapping will use the return address in LR in 
advance.
-         */
-        b     fail
  ENDPROC(enable_boot_cpu_mm)

  /*
--
2.25.1



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