On Tue, 16 Mar 2021 09:04:59 +0100
Ahmad Fatoum <a.fatoum@xxxxxxxxxxxxxx> wrote:
> We now have everything in place to migrate erizo to PBL.
> As currently, this is the only board, we can drop all non-PBL support
> in the same go.
...
> diff --git a/arch/riscv/boards/erizo/lowlevel.c b/arch/riscv/boards/erizo/lowlevel.c
> index f9c640c1123f..d9edb530b746 100644
> --- a/arch/riscv/boards/erizo/lowlevel.c
> +++ b/arch/riscv/boards/erizo/lowlevel.c
> @@ -1,35 +1,18 @@
> // SPDX-License-Identifier: GPL-2.0-only
> -/*
> - * Copyright (C) 2016 Antony Pavlov <antonynpavlov@xxxxxxxxx>
> - *
> - * This file is part of barebox.
> - *
> - * This program is distributed in the hope that it will be useful,
> - * but WITHOUT ANY WARRANTY; without even the implied warranty of
> - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> - * GNU General Public License for more details.
> - *
> - */
>
> #include <common.h>
> -#include <memory.h>
> -#include <asm-generic/memory_layout.h>
> -#include <asm/sections.h>
> +#include <asm/barebox-riscv.h>
> +#include <debug_ll.h>
>
> -void main_entry(void);
> -
> -/**
> - * Called plainly from assembler code
> - *
> - * @note The C environment isn't initialized yet
> - */
> -void main_entry(void)
> +ENTRY_FUNCTION(start_erizo_generic, a0, a1, a2)
> {
> - /* clear the BSS first */
> - memset(__bss_start, 0x00, __bss_stop - __bss_start);
> + extern char __dtb_z_erizo_generic_start[];
> +
> + debug_ll_ns16550_init();
> + putc_ll('>');
>
> - mem_malloc_init((void *)MALLOC_BASE,
> - (void *)(MALLOC_BASE + MALLOC_SIZE - 1));
> + /* On POR, we are running from read-only memory here. */
>
> - start_barebox();
> + barebox_riscv_entry(0x80000000, SZ_8M,
> + __dtb_z_erizo_generic_start + get_runtime_offset());
> }
Let's see first instructions of resulting barebox-erizo-generic.img image:
barebox$ xxd -l 16 -e -g 4 ./images/barebox-erizo-generic.img
00000000: ff010113 00112623 900007b7 08700713 ....#&........p.
one can disassembly it:
barebox$ riscv64-linux-gnu-objdump -D images/start_erizo_generic.pbl | head -n 9
images/start_erizo_generic.pbl: file format elf32-littleriscv
Disassembly of section .text:
00000000 <start_erizo_generic>:
0: ff010113 addi sp,sp,-16
4: 00112623 sw ra,12(sp)
In general case 'sp' is in indeterminate state at start.
But despite this we use 'sp'-based address
for storing 'ra' register in memory! (sw ra,12(sp))
This behaviour can be fixed with adding __naked to ENTRY_FUNCTION macro definition:
--- a/arch/riscv/include/asm/barebox-riscv.h
+++ b/arch/riscv/include/asm/barebox-riscv.h
@@ -78,7 +78,7 @@ static inline unsigned long riscv_mem_barebox_image(unsigned long membase,
#define ENTRY_FUNCTION(name, arg0, arg1, arg2) \
void name (ulong a0, ulong a1, ulong a2); \
- void __section(.text_head_entry_##name) name (ulong a0, ulong a1, ulong a2)
+ void __section(.text_head_entry_##name) __naked name (ulong a0, ulong a1, ulong a2)
/*
* When using compressed images in conjunction with relocatable images
--
Best regards,
Antony Pavlov
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