[Xen-changelog] [xen staging] xen/arm32: head: Don't setup the fixmap on secondary CPUs

[patchbot@xxxxxxx]

commit 6fa1798b2d7066f53f310f05e86b82c713e3bc42
Author:     Julien Grall <julien.grall@xxxxxxx>
AuthorDate: Mon Jul 22 14:24:43 2019 +0100
Commit:     Julien Grall <julien.grall@xxxxxxx>
CommitDate: Sat Sep 7 12:11:00 2019 +0100

    xen/arm32: head: Don't setup the fixmap on secondary CPUs
    
    setup_fixmap() will setup the fixmap in the boot page tables in order to
    use earlyprintk and also update the register r11 holding the address to
    the UART.
    
    However, secondary CPUs are not using earlyprintk between turning the
    MMU on and switching to the runtime page table. So setting up the
    fixmap in the boot pages table is pointless.
    
    This means most of setup_fixmap() is not necessary for the secondary
    CPUs. The update of UART address is now moved out of setup_fixmap() and
    duplicated in the CPU boot and secondary CPUs boot. Additionally, the
    call to setup_fixmap() is removed from secondary CPUs boot.
    
    Lastly, take the opportunity to replace load from literal pool with the
    new macro mov_w.
    
    Signed-off-by: Julien Grall <julien.grall@xxxxxxx>
    Reviewed-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>
---
 xen/arch/arm/arm32/head.S | 20 ++++++++------------
 1 file changed, 8 insertions(+), 12 deletions(-)

diff --git a/xen/arch/arm/arm32/head.S b/xen/arch/arm/arm32/head.S
index 0c95d1c432..8f945d318a 100644
--- a/xen/arch/arm/arm32/head.S
+++ b/xen/arch/arm/arm32/head.S
@@ -159,6 +159,10 @@ past_zImage:
         mov   pc, r0
 primary_switched:
         bl    setup_fixmap
+#ifdef CONFIG_EARLY_PRINTK
+        /* Use a virtual address to access the UART. */
+        mov_w r11, EARLY_UART_VIRTUAL_ADDRESS
+#endif
         b     launch
 ENDPROC(start)
 
@@ -201,8 +205,6 @@ GLOBAL(init_secondary)
         ldr   r0, =secondary_switched
         mov   pc, r0
 secondary_switched:
-        bl    setup_fixmap
-
         /*
          * Non-boot CPUs need to move on to the proper pagetables, which were
          * setup in init_secondary_pagetables.
@@ -221,6 +223,10 @@ secondary_switched:
         dsb                          /* Ensure completion of TLB+BP flush */
         isb
 
+#ifdef CONFIG_EARLY_PRINTK
+        /* Use a virtual address to access the UART. */
+        mov_w r11, EARLY_UART_VIRTUAL_ADDRESS
+#endif
         b     launch
 ENDPROC(init_secondary)
 
@@ -475,13 +481,6 @@ setup_fixmap:
          */
         dsb
 #if defined(CONFIG_EARLY_PRINTK) /* Fixmap is only used by early printk */
-        /*
-         * Non-boot CPUs don't need to rebuild the fixmap itself, just
-         * the mapping from boot_second to xen_fixmap
-         */
-        teq   r12, #0
-        bne   1f
-
         /* Add UART to the fixmap table */
         ldr   r1, =xen_fixmap        /* r1 := vaddr (xen_fixmap) */
         lsr   r2, r11, #THIRD_SHIFT
@@ -502,9 +501,6 @@ setup_fixmap:
         mov   r4, r4, lsr #(SECOND_SHIFT - 3)   /* r4 := Slot for FIXMAP(0) */
         mov   r3, #0x0
         strd  r2, r3, [r1, r4]       /* Map it in the fixmap's slot */
-
-        /* Use a virtual address to access the UART. */
-        ldr   r11, =EARLY_UART_VIRTUAL_ADDRESS
 #endif
 
         /*
--
generated by git-patchbot for /home/xen/git/xen.git#staging

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