Hello Peng,
I would specific the file modified in the title.
On 20/04/16 14:54, Peng Fan wrote:
The 'Base address for 4K mapping' is '(x19 >> THIRD_SHIFT) << THIRD_SHIFT'.
The computation is a sequence of 2 instructions. I gave a look to the
rest of the file and the comments are usually put on the first instruction.
So I would much prefer to stay consistent with the rest of the code.
Also we are building 4K page mapping, not section mapping.
To be fair, a page is a specialized section.
Signed-off-by: Peng Fan
Cc: Stefano Stabellini
Cc: Julien Grall
---
xen/arch/arm/arm64/head.S | 8
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/xen/arch/arm/arm64/head.S b/xen/arch/arm/arm64/head.S
index 946e2c9..05e3db0 100644
--- a/xen/arch/arm/arm64/head.S
+++ b/xen/arch/arm/arm64/head.S
@@ -471,10 +471,10 @@ skip_bss:
ldr x4, =boot_third
add x4, x4, x20/* x4 := paddr (boot_third) */
-lsr x2, x19, #THIRD_SHIFT /* Base address for 4K mapping */
-lsl x2, x2, #THIRD_SHIFT
-mov x3, #PT_MEM_L3 /* x2 := Section map */
-orr x2, x2, x3
+lsr x2, x19, #THIRD_SHIFT
+lsl x2, x2, #THIRD_SHIFT /* Base address for 4K mapping */
+mov x3, #PT_MEM_L3
+orr x2, x2, x3/* x2 := Page map */
The section map is the combination of 2 instructions. With this change
we don't know quickly what the purpose of "mov x3, #PT_MEM_L3".
/* ... map of vaddr(start) in boot_third */
mov x1, xzr
Regards,
--
Julien Grall
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