[PATCH v8 5/8] arm: armv8: save boot arguments

[Raymond Mao]

Save boot arguments x[0-3] into an array for handover of bloblist from
previous boot stage.

Signed-off-by: Raymond Mao <raymond.mao at linaro.org>
Suggested-by: Ard Biesheuvel <ardb at kernel.org>
---
Changes in v2
- New patch file created for v2.
Changes in V5
- Drop the dependence on OF_BOARD.
Changes in V7
- Exclude the saved_args when BLOBLIST is disabled.
Changes in V8
- Use PC-relative reference for saved_args.
- Add 4-byte alignment for saved_args.

 arch/arm/cpu/armv8/start.S | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/arch/arm/cpu/armv8/start.S b/arch/arm/cpu/armv8/start.S
index 6cc1d26e5e..7461280261 100644
--- a/arch/arm/cpu/armv8/start.S
+++ b/arch/arm/cpu/armv8/start.S
@@ -370,5 +370,28 @@ ENTRY(c_runtime_cpu_setup)
 ENDPROC(c_runtime_cpu_setup)
 
 WEAK(save_boot_params)
+#if (IS_ENABLED(CONFIG_BLOBLIST))
+	/* Calculate the PC-relative address of saved_args */
+	adr	x9, saved_args_offset
+	ldr	w10, saved_args_offset
+	add	x9, x9, w10, sxtw
+
+	stp	x0, x1, [x9]
+	stp	x2, x3, [x9, #16]
+#endif
 	b	save_boot_params_ret	/* back to my caller */
 ENDPROC(save_boot_params)
+
+#if (IS_ENABLED(CONFIG_BLOBLIST))
+saved_args_offset:
+	.long	saved_args - .	/* offset from current code to save_args */
+
+	.section .data
+	.align 2
+	.global saved_args
+saved_args:
+	.rept 4
+	.dword 0
+	.endr
+END(saved_args)
+#endif
-- 
2.25.1