zephyr/arch/x86/core/common.S
Jakub Michalski 0cf726b8ef arch/x86: multiboot: add bootargs support
Add bootargs support for multiboot. This
implements get_bootargs() when multiboot and
bootargs are selected in config.

Signed-off-by: Jakub Michalski <jmichalski@internships.antmicro.com>
Signed-off-by: Filip Kokosinski <fkokosinski@antmicro.com>
2024-09-05 12:30:39 -05:00

83 lines
2.1 KiB
ArmAsm

/*
* Copyright (c) 2019 Intel Corporation
* SPDX-License-Identifier: Apache-2.0
*/
#include <zephyr/arch/x86/multiboot.h>
#include <zephyr/devicetree.h>
/*
* This is included by ia32/crt0.S and intel64/locore.S
* at their 32-bit entry points to cover common ground.
*/
#ifdef CONFIG_MULTIBOOT_INFO
/*
* If we were loaded by a multiboot-compliant loader, then EAX
* contains MULTIBOOT_EAX_MAGIC and EBX points to a valid 'struct
* multiboot_info'; otherwise EBX is just junk. Check EAX early
* before it's clobbered and leave a sentinel (0) in EBX if invalid.
* The valid in EBX will be the argument to z_prep_c(), so the
* subsequent code must, of course, be sure to preserve it meanwhile.
*/
cmpl $MULTIBOOT_EAX_MAGIC, %eax
#ifndef CONFIG_DYNAMIC_BOOTARGS
je 1f
xorl %ebx, %ebx
1:
#else
movl $multiboot_cmdline, %edi
je setup_copy_cmdline
xorl %ebx, %ebx
jmp end_cmdline
setup_copy_cmdline:
testl $MULTIBOOT_INFO_FLAGS_CMDLINE, __multiboot_info_t_flags_OFFSET(%ebx)
jz end_cmdline
movl $multiboot_cmdline + CONFIG_BOOTARGS_ARGS_BUFFER_SIZE - 1, %edx
movl __multiboot_info_t_cmdline_OFFSET(%ebx), %esi
copy_cmdline:
cmpl %esi, %edx
je end_cmdline
cmpb $0, (%esi)
je end_cmdline
movsb
jmp copy_cmdline
end_cmdline:
movb $0, (%edi)
#endif
#endif
#ifdef CONFIG_PIC_DISABLE
/*
* "Disable" legacy i8259 interrupt controllers. Note that we
* can't actually disable them, but we mask all their interrupt
* sources which is effectively the same thing (almost).
*/
movb $0xff, %al
outb %al, $0x21
outb %al, $0xA1
#endif
#ifdef CONFIG_MULTIBOOT
jmp 1f
.align 4
.long MULTIBOOT_HEADER_MAGIC
.long MULTIBOOT_HEADER_FLAGS
.long -(MULTIBOOT_HEADER_MAGIC + MULTIBOOT_HEADER_FLAGS)
#if DT_HAS_COMPAT_STATUS_OKAY(intel_multiboot_framebuffer)
.fill 5,4,0 /* (unused exec layout) */
.long 0 /* linear graphics mode */
.long DT_PROP(DT_INST(0, intel_multiboot_framebuffer), width) /* width */
.long DT_PROP(DT_INST(0, intel_multiboot_framebuffer), height) /* height */
.long 32 /* depth */
#endif
1:
#endif