[xen staging] xen/arm64: head: Don't set x22 and update the documentation

[patchbot@xxxxxxx]

commit 471721c341cb56487324410f501b7f012d313e0e
Author:     Julien Grall <jgrall@xxxxxxxxxx>
AuthorDate: Fri Aug 12 20:24:40 2022 +0100
Commit:     Julien Grall <julien@xxxxxxx>
CommitDate: Wed Aug 31 20:10:47 2022 +0100

    xen/arm64: head: Don't set x22 and update the documentation
    
    Since commit 7e14a47e7c73 ("xen/arm64: head Rework and document
    launch()"), the boot code is setting x22 but not read it.
    
    So remove the two instructions setting x22 and update the documentation
    to show x22 has no specific purpose.
    
    Signed-off-by: Julien Grall <jgrall@xxxxxxxxxx>
    Reviewed-by: Bertrand Marquis <bertrand.marquis@xxxxxxx>
    Reviewed-by: Wei Chen <Wei.Chen@xxxxxxx>
---
 xen/arch/arm/arm64/head.S | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/xen/arch/arm/arm64/head.S b/xen/arch/arm/arm64/head.S
index 1babcc65d7..26cc7705f5 100644
--- a/xen/arch/arm/arm64/head.S
+++ b/xen/arch/arm/arm64/head.S
@@ -71,7 +71,7 @@
  *  x19 - paddr(start)
  *  x20 - phys offset
  *  x21 - DTB address (boot cpu only)
- *  x22 - is_secondary_cpu
+ *  x22 -
  *  x23 - UART address
  *  x24 -
  *  x25 -
@@ -305,8 +305,6 @@ real_start_efi:
 #endif
         PRINT("- Boot CPU booting -\r\n")
 
-        mov   x22, #0                /* x22 := is_secondary_cpu */
-
         bl    check_cpu_mode
         bl    cpu_init
         bl    create_page_tables
@@ -345,8 +343,6 @@ GLOBAL(init_secondary)
         adr   x19, start             /* x19 := paddr (start) */
         sub   x20, x19, x0           /* x20 := phys-offset */
 
-        mov   x22, #1                /* x22 := is_secondary_cpu */
-
         mrs   x0, mpidr_el1
         ldr   x13, =(~MPIDR_HWID_MASK)
         bic   x24, x0, x13           /* Mask out flags to get CPU ID */
--
generated by git-patchbot for /home/xen/git/xen.git#staging