[PATCH v3 2/3] xen/riscv: read/save hart_id and dtb_base passed by bootloader

[Oleksii Kurochko <oleksii.kurochko@xxxxxxxxx>]

Signed-off-by: Oleksii Kurochko <oleksii.kurochko@xxxxxxxxx>
---
Changes since v2:
 * Add the comment for start() function with the explanation what and
   how OpenSBI pass to start() function.
 * Clean up start() code related to read&save hart_id & dtb_base.  
---
Changes since v1:
 * read/save/pass of hart_id and  dtb_base passed by a bootloader
   were moved to head.S. 
 * Update start_xen() to recieve hard_id & dtb_base
---
 xen/arch/riscv/riscv64/head.S | 5 +++++
 xen/arch/riscv/setup.c        | 3 ++-
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/xen/arch/riscv/riscv64/head.S b/xen/arch/riscv/riscv64/head.S
index 52fa41c778..adf5d6c74a 100644
--- a/xen/arch/riscv/riscv64/head.S
+++ b/xen/arch/riscv/riscv64/head.S
@@ -2,6 +2,11 @@
 
         .section .text.header, "ax", %progbits
 
+        /*
+         * OpenSBI pass to start():
+         *   a0 -> hart_id ( bootcpu_id )
+         *   a1 -> dtb_base 
+         */
 ENTRY(start)
         /* Mask all interrupts */
         csrw    CSR_SIE, zero
diff --git a/xen/arch/riscv/setup.c b/xen/arch/riscv/setup.c
index 1c87899e8e..d9723fe1c0 100644
--- a/xen/arch/riscv/setup.c
+++ b/xen/arch/riscv/setup.c
@@ -7,7 +7,8 @@
 unsigned char __initdata cpu0_boot_stack[STACK_SIZE]
     __aligned(STACK_SIZE);
 
-void __init noreturn start_xen(void)
+void __init noreturn start_xen(unsigned long bootcpu_id,
+                               unsigned long dtb_base)
 {
     early_printk("Hello from C env\n");
 
-- 
2.39.0