[xen staging] xen/arm32: head: Don't set r12 and update the documentation

[patchbot@xxxxxxx]

commit faecea18d252f97c6ad41f0f457566ff2c125b8d
Author:     Julien Grall <jgrall@xxxxxxxxxx>
AuthorDate: Tue Mar 1 19:59:54 2022 +0000
Commit:     Julien Grall <jgrall@xxxxxxxxxx>
CommitDate: Tue Mar 1 20:01:12 2022 +0000

    xen/arm32: head: Don't set r12 and update the documentation
    
    Since commit 54c4ae18d158 ("xen/arm32: head: Rework and document
    launch()"), the boot code is setting r12 but not read it.
    
    So remove the two instructions setting r12 and update the documentation
    to show r12 has no specific purpose.
    
    Signed-off-by: Julien Grall <jgrall@xxxxxxxxxx>
    Reviewed-by: Michal Orzel <michal.orzel@xxxxxxx>
    Reviewed-by: Bertrand Marquis <bertrand.marquis@xxxxxxx>
---
 xen/arch/arm/arm32/head.S | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/xen/arch/arm/arm32/head.S b/xen/arch/arm/arm32/head.S
index 13cfc837d3..7a906167ef 100644
--- a/xen/arch/arm/arm32/head.S
+++ b/xen/arch/arm/arm32/head.S
@@ -79,7 +79,7 @@
  *   r9  - paddr(start)
  *   r10 - phys offset
  *   r11 - UART address
- *   r12 - is_secondary_cpu
+ *   r12 -
  *   r13 - SP
  *   r14 - LR
  *   r15 - PC
@@ -166,8 +166,6 @@ past_zImage:
 #endif
         PRINT("- Boot CPU booting -\r\n")
 
-        mov   r12, #0                /* r12 := is_secondary_cpu */
-
         bl    check_cpu_mode
         bl    cpu_init
         bl    create_page_tables
@@ -206,8 +204,6 @@ GLOBAL(init_secondary)
         adr   r9, start              /* r9  := paddr (start) */
         sub   r10, r9, r0            /* r10 := phys-offset */
 
-        mov   r12, #1                /* r12 := is_secondary_cpu */
-
         mrc   CP32(r1, MPIDR)
         bic   r7, r1, #(~MPIDR_HWID_MASK) /* Mask out flags to get CPU ID */
 
--
generated by git-patchbot for /home/xen/git/xen.git#staging