[PATCH] arm64: Properly clear BSS

[Ilias Apalodimas]

Brock reports a breakage on an RK3568 SoC. His patch is
correct but he never followed up on the requested changes.

We currently use ldr to calculate the address of __bss_start and
__bss_end. However the absolute addresses of the literal pool are never
relocated and we end up clearing the wrong memory section. Use
PC-relative addressing instead.

Link: https://lore.kernel.org/u-boot/zfknlzcemnnaka5w2er5wjwefwoidrpndc4gjhx6d5xr6nlcjr@pasfayjiutii/

Suggested-by: brock_zheng <yzheng at techyauld.com>
Reported-by: brock_zheng <yzheng at techyauld.com>
Signed-off-by: Ilias Apalodimas <ilias.apalodimas at linaro.org>
---
 arch/arm/lib/crt0_64.S | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/arch/arm/lib/crt0_64.S b/arch/arm/lib/crt0_64.S
index f3f279f2c39c..3e7627aa389b 100644
--- a/arch/arm/lib/crt0_64.S
+++ b/arch/arm/lib/crt0_64.S
@@ -158,8 +158,10 @@ relocation_return:
 /*
  * Clear BSS section
  */
-	ldr	x0, =__bss_start		/* this is auto-relocated! */
-	ldr	x1, =__bss_end			/* this is auto-relocated! */
+	adrp	x0, __bss_start
+	add	x0, x0, #:lo12:__bss_start
+	adrp	x1, __bss_end
+	add	x1, x1, #:lo12:__bss_end
 clear_loop:
 	str	xzr, [x0], #8
 	cmp	x0, x1
-- 
2.50.1