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| author | Huacai Chen <chenhuacai@loongson.cn> | 2022-05-31 13:04:11 +0300 |
|---|---|---|
| committer | Huacai Chen <chenhuacai@loongson.cn> | 2022-06-03 15:09:28 +0300 |
| commit | 628c3bb40e9a8cefc0a6fde28b7b66bfe46d1dc2 (patch) | |
| tree | 37f8cf6768e1bab484836d7c2e456475efc7262a /arch/loongarch/kernel/head.S | |
| parent | b738c106f7355e318ca47a3b981688efe1bc12fb (diff) | |
| download | linux-628c3bb40e9a8cefc0a6fde28b7b66bfe46d1dc2.tar.xz | |
LoongArch: Add boot and setup routines
Add basic boot, setup and reset routines for LoongArch. Now, LoongArch
machines use UEFI-based firmware. The firmware passes configuration
information to the kernel via ACPI and DMI/SMBIOS.
Currently an existing interface between the kernel and the bootloader
is implemented. Kernel gets 2 values from the bootloader, passed in
registers a0 and a1; a0 is an "EFI boot flag" distinguishing UEFI and
non-UEFI firmware, while a1 is a pointer to an FDT with systable,
memmap, cmdline and initrd information.
The standard UEFI boot protocol (EFISTUB) will be added later.
Cc: linux-efi@vger.kernel.org
Cc: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: WANG Xuerui <git@xen0n.name>
Reviewed-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Co-developed-by: Yun Liu <liuyun@loongson.cn>
Signed-off-by: Yun Liu <liuyun@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Diffstat (limited to 'arch/loongarch/kernel/head.S')
| -rw-r--r-- | arch/loongarch/kernel/head.S | 68 |
1 files changed, 68 insertions, 0 deletions
diff --git a/arch/loongarch/kernel/head.S b/arch/loongarch/kernel/head.S new file mode 100644 index 000000000000..57dabb699bb7 --- /dev/null +++ b/arch/loongarch/kernel/head.S @@ -0,0 +1,68 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Copyright (C) 2020-2022 Loongson Technology Corporation Limited + */ +#include <linux/init.h> +#include <linux/threads.h> + +#include <asm/addrspace.h> +#include <asm/asm.h> +#include <asm/asmmacro.h> +#include <asm/regdef.h> +#include <asm/loongarch.h> +#include <asm/stackframe.h> + + __REF + +SYM_ENTRY(_stext, SYM_L_GLOBAL, SYM_A_NONE) + +SYM_CODE_START(kernel_entry) # kernel entry point + + /* Config direct window and set PG */ + li.d t0, CSR_DMW0_INIT # UC, PLV0, 0x8000 xxxx xxxx xxxx + csrwr t0, LOONGARCH_CSR_DMWIN0 + li.d t0, CSR_DMW1_INIT # CA, PLV0, 0x9000 xxxx xxxx xxxx + csrwr t0, LOONGARCH_CSR_DMWIN1 + /* Enable PG */ + li.w t0, 0xb0 # PLV=0, IE=0, PG=1 + csrwr t0, LOONGARCH_CSR_CRMD + li.w t0, 0x04 # PLV=0, PIE=1, PWE=0 + csrwr t0, LOONGARCH_CSR_PRMD + li.w t0, 0x00 # FPE=0, SXE=0, ASXE=0, BTE=0 + csrwr t0, LOONGARCH_CSR_EUEN + + /* We might not get launched at the address the kernel is linked to, + so we jump there. */ + la.abs t0, 0f + jirl zero, t0, 0 +0: + la t0, __bss_start # clear .bss + st.d zero, t0, 0 + la t1, __bss_stop - LONGSIZE +1: + addi.d t0, t0, LONGSIZE + st.d zero, t0, 0 + bne t0, t1, 1b + + la t0, fw_arg0 + st.d a0, t0, 0 # firmware arguments + la t0, fw_arg1 + st.d a1, t0, 0 + + /* KSave3 used for percpu base, initialized as 0 */ + csrwr zero, PERCPU_BASE_KS + /* GPR21 used for percpu base (runtime), initialized as 0 */ + or u0, zero, zero + + la tp, init_thread_union + /* Set the SP after an empty pt_regs. */ + PTR_LI sp, (_THREAD_SIZE - 32 - PT_SIZE) + PTR_ADD sp, sp, tp + set_saved_sp sp, t0, t1 + PTR_ADDI sp, sp, -4 * SZREG # init stack pointer + + bl start_kernel + +SYM_CODE_END(kernel_entry) + +SYM_ENTRY(kernel_entry_end, SYM_L_GLOBAL, SYM_A_NONE) |