Subject: [kvm-unit-tests v4 10/12] powerpc: Discover runtime load address dynamically

From: Nicholas Piggin <[email-masked]>
Date: Thu, 8 Jun 2023 17:58:24 +1000

The next change will load the kernels at different addresses depending
on test options, so this needs to be reverted back to dynamic
discovery.

Acked-by: Thomas Huth <[email-masked]>
Signed-off-by: Nicholas Piggin <[email-masked]>
---
 powerpc/cstart64.S | 19 ++++++++++++++-----
 1 file changed, 14 insertions(+), 5 deletions(-)

diff --git a/powerpc/cstart64.S b/powerpc/cstart64.S
index b7514100..e18ae9a2 100644
--- a/powerpc/cstart64.S
+++ b/powerpc/cstart64.S
@@ -33,9 +33,14 @@ start:
 	 * We were loaded at QEMU's kernel load address, but we're not
 	 * allowed to link there due to how QEMU deals with linker VMAs,
 	 * so we just linked at zero. This means the first thing to do is
-	 * to find our stack and toc, and then do a relocate.
+	 * to find our stack and toc, and then do a relocate. powernv and
+	 * pseries load addresses are not the same, so find the address
+	 * dynamically:
 	 */
-	LOAD_REG_IMMEDIATE(r31, SPAPR_KERNEL_LOAD_ADDR)
+	bl	0f
+0:	mflr	r31
+	subi	r31, r31, 0b - start	/* QEMU's kernel load address */
+
 	ld	r1, (p_stack - start)(r31)
 	ld	r2, (p_toc - start)(r31)
 	add	r1, r1, r31
@@ -114,8 +119,11 @@ p_toc:		.llong  tocptr
 p_dyn:		.llong  dynamic_start
 
 .text
+start_text:
 .align 3
+p_toc_text:	.llong	tocptr
 
+.align 3
 .globl hcall
 hcall:
 	sc	1
@@ -185,9 +193,10 @@ call_handler:
 	std	r0,_CCR(r1)
 
 	/* restore TOC pointer */
-
-	LOAD_REG_IMMEDIATE(r31, SPAPR_KERNEL_LOAD_ADDR)
-	ld	r2, (p_toc - start)(r31)
+	bl	0f
+0:	mflr	r31
+	subi	r31, r31, 0b - start_text
+	ld	r2, (p_toc_text - start_text)(r31)
 
 	/* FIXME: build stack frame */
 
-- 
2.40.1