[kvm-unit-tests v3 11/13] powerpc: Discover runtime load address dynamically

Nicholas Piggin
2023-03-27T12:46:25Z

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

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
---
powerpc/cstart64.S | 19 ++++++++++++++-----
1 file changed, 14 insertions(+), 5 deletions(-)

diff --git a/powerpc/cstart64.S b/powerpc/cstart64.S
index 1bd0437..0592e03 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 addreses 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 */

--
2.37.2