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linux/arch/loongarch/kernel/head.S

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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>
2022-05-31 18:04:11 +08:00
/* 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>
LoongArch: Use generic BUG() handler Inspired by commit 9fb7410f955("arm64/BUG: Use BRK instruction for generic BUG traps"), do similar for LoongArch to use generic BUG() handler. This patch uses the BREAK software breakpoint instruction to generate a trap instead, similarly to most other arches, with the generic BUG code generating the dmesg boilerplate. This allows bug metadata to be moved to a separate table and reduces the amount of inline code at BUG() and WARN() sites. This also avoids clobbering any registers before they can be dumped. To mitigate the size of the bug table further, this patch makes use of the existing infrastructure for encoding addresses within the bug table as 32-bit relative pointers instead of absolute pointers. (Note: this limits the max kernel size to 2GB.) Before patch: [ 3018.338013] lkdtm: Performing direct entry BUG [ 3018.342445] Kernel bug detected[#5]: [ 3018.345992] CPU: 2 PID: 865 Comm: cat Tainted: G D 6.0.0-rc6+ #35 After patch: [ 125.585985] lkdtm: Performing direct entry BUG [ 125.590433] ------------[ cut here ]------------ [ 125.595020] kernel BUG at drivers/misc/lkdtm/bugs.c:78! [ 125.600211] Oops - BUG[#1]: [ 125.602980] CPU: 3 PID: 410 Comm: cat Not tainted 6.0.0-rc6+ #36 Out-of-line file/line data information obtained compared to before. Signed-off-by: Youling Tang <tangyouling@loongson.cn> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
2022-10-12 16:36:19 +08:00
#include <asm/bug.h>
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>
2022-05-31 18:04:11 +08:00
#include <asm/regdef.h>
#include <asm/loongarch.h>
#include <asm/stackframe.h>
efi/loongarch: Add efistub booting support This patch adds efistub booting support, which is the standard UEFI boot protocol for LoongArch to use. We use generic efistub, which means we can pass boot information (i.e., system table, memory map, kernel command line, initrd) via a light FDT and drop a lot of non-standard code. We use a flat mapping to map the efi runtime in the kernel's address space. In efi, VA = PA; in kernel, VA = PA + PAGE_OFFSET. As a result, flat mapping is not identity mapping, SetVirtualAddressMap() is still needed for the efi runtime. Tested-by: Xi Ruoyao <xry111@xry111.site> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn> [ardb: change fpic to fpie as suggested by Xi Ruoyao] Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2022-08-19 18:20:37 +08:00
#ifdef CONFIG_EFI_STUB
#include "efi-header.S"
__HEAD
_head:
.word MZ_MAGIC /* "MZ", MS-DOS header */
LoongArch: Add kexec support Add three new files, kexec.h, machine_kexec.c and relocate_kernel.S to the LoongArch architecture, so as to add support for the kexec re-boot mechanism (CONFIG_KEXEC) on LoongArch platforms. Kexec supports loading vmlinux.elf in ELF format and vmlinux.efi in PE format. I tested kexec on LoongArch machines (Loongson-3A5000) and it works as expected: $ sudo kexec -l /boot/vmlinux.efi --reuse-cmdline $ sudo kexec -e Signed-off-by: Youling Tang <tangyouling@loongson.cn> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
2022-10-12 16:36:19 +08:00
.org 0x8
.dword kernel_entry /* Kernel entry point */
.dword _end - _text /* Kernel image effective size */
.quad 0 /* Kernel image load offset from start of RAM */
.org 0x3c /* 0x20 ~ 0x3b reserved */
efi/loongarch: Add efistub booting support This patch adds efistub booting support, which is the standard UEFI boot protocol for LoongArch to use. We use generic efistub, which means we can pass boot information (i.e., system table, memory map, kernel command line, initrd) via a light FDT and drop a lot of non-standard code. We use a flat mapping to map the efi runtime in the kernel's address space. In efi, VA = PA; in kernel, VA = PA + PAGE_OFFSET. As a result, flat mapping is not identity mapping, SetVirtualAddressMap() is still needed for the efi runtime. Tested-by: Xi Ruoyao <xry111@xry111.site> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn> [ardb: change fpic to fpie as suggested by Xi Ruoyao] Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2022-08-19 18:20:37 +08:00
.long pe_header - _head /* Offset to the PE header */
pe_header:
__EFI_PE_HEADER
SYM_DATA(kernel_asize, .long _end - _text);
SYM_DATA(kernel_fsize, .long _edata - _text);
SYM_DATA(kernel_offset, .long kernel_offset - _text);
#endif
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>
2022-05-31 18:04:11 +08:00
__REF
LoongArch: Align the address of kernel_entry to 4KB Align the address of kernel_entry to 4KB, to avoid early tlb miss exception in case the entry code crosses page boundary. Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
2022-09-26 22:25:29 +08:00
.align 12
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>
2022-05-31 18:04:11 +08:00
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
LoongArch: Jump to the link address before enable PG The kernel entry points of both boot CPU (i.e., kernel_entry) and non- boot CPUs (i.e., smpboot_entry) may be physical address from BootLoader (in DA mode or identity-mapping PG mode). So we should jump to the link address before PG enabled (because DA is disabled at the same time) and just after DMW configured. Specifically: With some older firmwares, non-boot CPUs started with PG enabled, but this need firmware cooperation in the form of a temporary page table, which is deemed unnecessary. OTOH, latest firmware versions configure the non-boot CPUs to start in DA mode, so kernel-side changes are needed. Reviewed-by: WANG Xuerui <git@xen0n.name> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
2022-08-11 20:52:12 +08:00
/* We might not get launched at the address the kernel is linked to,
so we jump there. */
la.abs t0, 0f
jr t0
0:
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>
2022-05-31 18:04:11 +08:00
/* 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
LoongArch: Adjust symbol addressing for AS_HAS_EXPLICIT_RELOCS If explicit relocation hints are used by the toolchain, -Wa,-mla-* options will be useless for the C code. So only use them for the !CONFIG_AS_HAS_EXPLICIT_RELOCS case. Replace "la" with "la.pcrel" in head.S to keep the semantic consistent with new and old toolchains for the low level startup code. For per-CPU variables, the "address" of the symbol is actually an offset from $r21. The value is near the loading address of main kernel image, but far from the loading address of modules. So we use model("extreme") attibute to tell the compiler that a PC-relative addressing with 32-bit offset is not sufficient for local per-CPU variables. The behavior with different assemblers and compilers are summarized in the following table: AS has CC has explicit relocs explicit relocs * Behavior ============================================================== No No Use la.* macros. No change from Linux 6.0. -------------------------------------------------------------- No Yes Disable explicit relocs. No change from Linux 6.0. -------------------------------------------------------------- Yes No Not supported. -------------------------------------------------------------- Yes Yes Enable explicit relocs. No -Wa,-mla* options used. ============================================================== *: We assume CC must have model attribute if it has explicit relocs. Both features are added in GCC 13 development cycle, so any GCC release >= 13 should be OK. Using early GCC 13 development snapshots may produce modules with unsupported relocations. Link: https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=f09482a Link: https://gcc.gnu.org/r13-1834 Link: https://gcc.gnu.org/r13-2199 Tested-by: WANG Xuerui <git@xen0n.name> Signed-off-by: Xi Ruoyao <xry111@xry111.site> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
2022-10-12 16:36:08 +08:00
la.pcrel t0, __bss_start # clear .bss
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>
2022-05-31 18:04:11 +08:00
st.d zero, t0, 0
LoongArch: Adjust symbol addressing for AS_HAS_EXPLICIT_RELOCS If explicit relocation hints are used by the toolchain, -Wa,-mla-* options will be useless for the C code. So only use them for the !CONFIG_AS_HAS_EXPLICIT_RELOCS case. Replace "la" with "la.pcrel" in head.S to keep the semantic consistent with new and old toolchains for the low level startup code. For per-CPU variables, the "address" of the symbol is actually an offset from $r21. The value is near the loading address of main kernel image, but far from the loading address of modules. So we use model("extreme") attibute to tell the compiler that a PC-relative addressing with 32-bit offset is not sufficient for local per-CPU variables. The behavior with different assemblers and compilers are summarized in the following table: AS has CC has explicit relocs explicit relocs * Behavior ============================================================== No No Use la.* macros. No change from Linux 6.0. -------------------------------------------------------------- No Yes Disable explicit relocs. No change from Linux 6.0. -------------------------------------------------------------- Yes No Not supported. -------------------------------------------------------------- Yes Yes Enable explicit relocs. No -Wa,-mla* options used. ============================================================== *: We assume CC must have model attribute if it has explicit relocs. Both features are added in GCC 13 development cycle, so any GCC release >= 13 should be OK. Using early GCC 13 development snapshots may produce modules with unsupported relocations. Link: https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=f09482a Link: https://gcc.gnu.org/r13-1834 Link: https://gcc.gnu.org/r13-2199 Tested-by: WANG Xuerui <git@xen0n.name> Signed-off-by: Xi Ruoyao <xry111@xry111.site> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
2022-10-12 16:36:08 +08:00
la.pcrel t1, __bss_stop - LONGSIZE
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>
2022-05-31 18:04:11 +08:00
1:
addi.d t0, t0, LONGSIZE
st.d zero, t0, 0
bne t0, t1, 1b
LoongArch: Adjust symbol addressing for AS_HAS_EXPLICIT_RELOCS If explicit relocation hints are used by the toolchain, -Wa,-mla-* options will be useless for the C code. So only use them for the !CONFIG_AS_HAS_EXPLICIT_RELOCS case. Replace "la" with "la.pcrel" in head.S to keep the semantic consistent with new and old toolchains for the low level startup code. For per-CPU variables, the "address" of the symbol is actually an offset from $r21. The value is near the loading address of main kernel image, but far from the loading address of modules. So we use model("extreme") attibute to tell the compiler that a PC-relative addressing with 32-bit offset is not sufficient for local per-CPU variables. The behavior with different assemblers and compilers are summarized in the following table: AS has CC has explicit relocs explicit relocs * Behavior ============================================================== No No Use la.* macros. No change from Linux 6.0. -------------------------------------------------------------- No Yes Disable explicit relocs. No change from Linux 6.0. -------------------------------------------------------------- Yes No Not supported. -------------------------------------------------------------- Yes Yes Enable explicit relocs. No -Wa,-mla* options used. ============================================================== *: We assume CC must have model attribute if it has explicit relocs. Both features are added in GCC 13 development cycle, so any GCC release >= 13 should be OK. Using early GCC 13 development snapshots may produce modules with unsupported relocations. Link: https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=f09482a Link: https://gcc.gnu.org/r13-1834 Link: https://gcc.gnu.org/r13-2199 Tested-by: WANG Xuerui <git@xen0n.name> Signed-off-by: Xi Ruoyao <xry111@xry111.site> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
2022-10-12 16:36:08 +08:00
la.pcrel t0, fw_arg0
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>
2022-05-31 18:04:11 +08:00
st.d a0, t0, 0 # firmware arguments
LoongArch: Adjust symbol addressing for AS_HAS_EXPLICIT_RELOCS If explicit relocation hints are used by the toolchain, -Wa,-mla-* options will be useless for the C code. So only use them for the !CONFIG_AS_HAS_EXPLICIT_RELOCS case. Replace "la" with "la.pcrel" in head.S to keep the semantic consistent with new and old toolchains for the low level startup code. For per-CPU variables, the "address" of the symbol is actually an offset from $r21. The value is near the loading address of main kernel image, but far from the loading address of modules. So we use model("extreme") attibute to tell the compiler that a PC-relative addressing with 32-bit offset is not sufficient for local per-CPU variables. The behavior with different assemblers and compilers are summarized in the following table: AS has CC has explicit relocs explicit relocs * Behavior ============================================================== No No Use la.* macros. No change from Linux 6.0. -------------------------------------------------------------- No Yes Disable explicit relocs. No change from Linux 6.0. -------------------------------------------------------------- Yes No Not supported. -------------------------------------------------------------- Yes Yes Enable explicit relocs. No -Wa,-mla* options used. ============================================================== *: We assume CC must have model attribute if it has explicit relocs. Both features are added in GCC 13 development cycle, so any GCC release >= 13 should be OK. Using early GCC 13 development snapshots may produce modules with unsupported relocations. Link: https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=f09482a Link: https://gcc.gnu.org/r13-1834 Link: https://gcc.gnu.org/r13-2199 Tested-by: WANG Xuerui <git@xen0n.name> Signed-off-by: Xi Ruoyao <xry111@xry111.site> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
2022-10-12 16:36:08 +08:00
la.pcrel t0, fw_arg1
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>
2022-05-31 18:04:11 +08:00
st.d a1, t0, 0
LoongArch: Adjust symbol addressing for AS_HAS_EXPLICIT_RELOCS If explicit relocation hints are used by the toolchain, -Wa,-mla-* options will be useless for the C code. So only use them for the !CONFIG_AS_HAS_EXPLICIT_RELOCS case. Replace "la" with "la.pcrel" in head.S to keep the semantic consistent with new and old toolchains for the low level startup code. For per-CPU variables, the "address" of the symbol is actually an offset from $r21. The value is near the loading address of main kernel image, but far from the loading address of modules. So we use model("extreme") attibute to tell the compiler that a PC-relative addressing with 32-bit offset is not sufficient for local per-CPU variables. The behavior with different assemblers and compilers are summarized in the following table: AS has CC has explicit relocs explicit relocs * Behavior ============================================================== No No Use la.* macros. No change from Linux 6.0. -------------------------------------------------------------- No Yes Disable explicit relocs. No change from Linux 6.0. -------------------------------------------------------------- Yes No Not supported. -------------------------------------------------------------- Yes Yes Enable explicit relocs. No -Wa,-mla* options used. ============================================================== *: We assume CC must have model attribute if it has explicit relocs. Both features are added in GCC 13 development cycle, so any GCC release >= 13 should be OK. Using early GCC 13 development snapshots may produce modules with unsupported relocations. Link: https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=f09482a Link: https://gcc.gnu.org/r13-1834 Link: https://gcc.gnu.org/r13-2199 Tested-by: WANG Xuerui <git@xen0n.name> Signed-off-by: Xi Ruoyao <xry111@xry111.site> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
2022-10-12 16:36:08 +08:00
la.pcrel t0, fw_arg2
efi/loongarch: libstub: remove dependency on flattened DT LoongArch does not use FDT or DT natively [yet], and the only reason it currently uses it is so that it can reuse the existing EFI stub code. Overloading the DT with data passed between the EFI stub and the core kernel has been a source of problems: there is the overlap between information provided by EFI which DT can also provide (initrd base/size, command line, memory descriptions), requiring us to reason about which is which and what to prioritize. It has also resulted in ABI leaks, i.e., internal ABI being promoted to external ABI inadvertently because the bootloader can set the EFI stub's DT properties as well (e.g., "kaslr-seed"). This has become especially problematic with boot environments that want to pretend that EFI boot is being done (to access ACPI and SMBIOS tables, for instance) but have no ability to execute the EFI stub, and so the environment that the EFI stub creates is emulated [poorly, in some cases]. Another downside of treating DT like this is that the DT binary that the kernel receives is different from the one created by the firmware, which is undesirable in the context of secure and measured boot. Given that LoongArch support in Linux is brand new, we can avoid these pitfalls, and treat the DT strictly as a hardware description, and use a separate handover method between the EFI stub and the kernel. Now that initrd loading and passing the EFI memory map have been refactored into pure EFI routines that use EFI configuration tables, the only thing we need to pass directly is the kernel command line (even if we could pass this via a config table as well, it is used extremely early, so passing it directly is preferred in this case.) Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Acked-by: Huacai Chen <chenhuacai@loongson.cn>
2022-09-16 19:48:53 +02:00
st.d a2, t0, 0
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>
2022-05-31 18:04:11 +08:00
/* KSave3 used for percpu base, initialized as 0 */
csrwr zero, PERCPU_BASE_KS
/* GPR21 used for percpu base (runtime), initialized as 0 */
LoongArch: Use the "move" pseudo-instruction where applicable Some of the assembly code in the LoongArch port likely originated from a time when the assembler did not support pseudo-instructions like "move" or "jr", so the desugared form was used and readability suffers (to a minor degree) as a result. As the upstream toolchain supports these pseudo-instructions from the beginning, migrate the existing few usages to them for better readability. Signed-off-by: WANG Xuerui <git@xen0n.name> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
2022-07-26 23:57:18 +08:00
move u0, zero
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>
2022-05-31 18:04:11 +08:00
LoongArch: Adjust symbol addressing for AS_HAS_EXPLICIT_RELOCS If explicit relocation hints are used by the toolchain, -Wa,-mla-* options will be useless for the C code. So only use them for the !CONFIG_AS_HAS_EXPLICIT_RELOCS case. Replace "la" with "la.pcrel" in head.S to keep the semantic consistent with new and old toolchains for the low level startup code. For per-CPU variables, the "address" of the symbol is actually an offset from $r21. The value is near the loading address of main kernel image, but far from the loading address of modules. So we use model("extreme") attibute to tell the compiler that a PC-relative addressing with 32-bit offset is not sufficient for local per-CPU variables. The behavior with different assemblers and compilers are summarized in the following table: AS has CC has explicit relocs explicit relocs * Behavior ============================================================== No No Use la.* macros. No change from Linux 6.0. -------------------------------------------------------------- No Yes Disable explicit relocs. No change from Linux 6.0. -------------------------------------------------------------- Yes No Not supported. -------------------------------------------------------------- Yes Yes Enable explicit relocs. No -Wa,-mla* options used. ============================================================== *: We assume CC must have model attribute if it has explicit relocs. Both features are added in GCC 13 development cycle, so any GCC release >= 13 should be OK. Using early GCC 13 development snapshots may produce modules with unsupported relocations. Link: https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=f09482a Link: https://gcc.gnu.org/r13-1834 Link: https://gcc.gnu.org/r13-2199 Tested-by: WANG Xuerui <git@xen0n.name> Signed-off-by: Xi Ruoyao <xry111@xry111.site> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
2022-10-12 16:36:08 +08:00
la.pcrel tp, init_thread_union
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>
2022-05-31 18:04:11 +08:00
/* Set the SP after an empty pt_regs. */
LoongArch: Remove unused kernel stack padding The current LoongArch kernel stack is padded as if obeying the MIPS o32 calling convention (32 bytes), signifying the port's MIPS lineage but no longer making sense. Remove the padding for clarity. Reviewed-by: WANG Xuerui <git@xen0n.name> Signed-off-by: Jinyang He <hejinyang@loongson.cn> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
2022-10-29 16:29:31 +08:00
PTR_LI sp, (_THREAD_SIZE - PT_SIZE)
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>
2022-05-31 18:04:11 +08:00
PTR_ADD sp, sp, tp
set_saved_sp sp, t0, t1
bl start_kernel
LoongArch: Use generic BUG() handler Inspired by commit 9fb7410f955("arm64/BUG: Use BRK instruction for generic BUG traps"), do similar for LoongArch to use generic BUG() handler. This patch uses the BREAK software breakpoint instruction to generate a trap instead, similarly to most other arches, with the generic BUG code generating the dmesg boilerplate. This allows bug metadata to be moved to a separate table and reduces the amount of inline code at BUG() and WARN() sites. This also avoids clobbering any registers before they can be dumped. To mitigate the size of the bug table further, this patch makes use of the existing infrastructure for encoding addresses within the bug table as 32-bit relative pointers instead of absolute pointers. (Note: this limits the max kernel size to 2GB.) Before patch: [ 3018.338013] lkdtm: Performing direct entry BUG [ 3018.342445] Kernel bug detected[#5]: [ 3018.345992] CPU: 2 PID: 865 Comm: cat Tainted: G D 6.0.0-rc6+ #35 After patch: [ 125.585985] lkdtm: Performing direct entry BUG [ 125.590433] ------------[ cut here ]------------ [ 125.595020] kernel BUG at drivers/misc/lkdtm/bugs.c:78! [ 125.600211] Oops - BUG[#1]: [ 125.602980] CPU: 3 PID: 410 Comm: cat Not tainted 6.0.0-rc6+ #36 Out-of-line file/line data information obtained compared to before. Signed-off-by: Youling Tang <tangyouling@loongson.cn> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
2022-10-12 16:36:19 +08:00
ASM_BUG()
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>
2022-05-31 18:04:11 +08:00
SYM_CODE_END(kernel_entry)
LoongArch: Add multi-processor (SMP) support LoongArch-based procesors have 4, 8 or 16 cores per package. This patch adds multi-processor (SMP) support for LoongArch. Reviewed-by: WANG Xuerui <git@xen0n.name> Reviewed-by: Jiaxun Yang <jiaxun.yang@flygoat.com> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
2022-05-31 18:04:12 +08:00
#ifdef CONFIG_SMP
/*
* SMP slave cpus entry point. Board specific code for bootstrap calls this
* function after setting up the stack and tp registers.
*/
SYM_CODE_START(smpboot_entry)
li.d t0, CSR_DMW0_INIT # UC, PLV0
csrwr t0, LOONGARCH_CSR_DMWIN0
li.d t0, CSR_DMW1_INIT # CA, PLV0
csrwr t0, LOONGARCH_CSR_DMWIN1
LoongArch: Jump to the link address before enable PG The kernel entry points of both boot CPU (i.e., kernel_entry) and non- boot CPUs (i.e., smpboot_entry) may be physical address from BootLoader (in DA mode or identity-mapping PG mode). So we should jump to the link address before PG enabled (because DA is disabled at the same time) and just after DMW configured. Specifically: With some older firmwares, non-boot CPUs started with PG enabled, but this need firmware cooperation in the form of a temporary page table, which is deemed unnecessary. OTOH, latest firmware versions configure the non-boot CPUs to start in DA mode, so kernel-side changes are needed. Reviewed-by: WANG Xuerui <git@xen0n.name> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
2022-08-11 20:52:12 +08:00
la.abs t0, 0f
jr t0
0:
/* Enable PG */
LoongArch: Add multi-processor (SMP) support LoongArch-based procesors have 4, 8 or 16 cores per package. This patch adds multi-processor (SMP) support for LoongArch. Reviewed-by: WANG Xuerui <git@xen0n.name> Reviewed-by: Jiaxun Yang <jiaxun.yang@flygoat.com> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
2022-05-31 18:04:12 +08:00
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
la.abs t0, cpuboot_data
ld.d sp, t0, CPU_BOOT_STACK
ld.d tp, t0, CPU_BOOT_TINFO
bl start_secondary
LoongArch: Use generic BUG() handler Inspired by commit 9fb7410f955("arm64/BUG: Use BRK instruction for generic BUG traps"), do similar for LoongArch to use generic BUG() handler. This patch uses the BREAK software breakpoint instruction to generate a trap instead, similarly to most other arches, with the generic BUG code generating the dmesg boilerplate. This allows bug metadata to be moved to a separate table and reduces the amount of inline code at BUG() and WARN() sites. This also avoids clobbering any registers before they can be dumped. To mitigate the size of the bug table further, this patch makes use of the existing infrastructure for encoding addresses within the bug table as 32-bit relative pointers instead of absolute pointers. (Note: this limits the max kernel size to 2GB.) Before patch: [ 3018.338013] lkdtm: Performing direct entry BUG [ 3018.342445] Kernel bug detected[#5]: [ 3018.345992] CPU: 2 PID: 865 Comm: cat Tainted: G D 6.0.0-rc6+ #35 After patch: [ 125.585985] lkdtm: Performing direct entry BUG [ 125.590433] ------------[ cut here ]------------ [ 125.595020] kernel BUG at drivers/misc/lkdtm/bugs.c:78! [ 125.600211] Oops - BUG[#1]: [ 125.602980] CPU: 3 PID: 410 Comm: cat Not tainted 6.0.0-rc6+ #36 Out-of-line file/line data information obtained compared to before. Signed-off-by: Youling Tang <tangyouling@loongson.cn> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
2022-10-12 16:36:19 +08:00
ASM_BUG()
LoongArch: Add multi-processor (SMP) support LoongArch-based procesors have 4, 8 or 16 cores per package. This patch adds multi-processor (SMP) support for LoongArch. Reviewed-by: WANG Xuerui <git@xen0n.name> Reviewed-by: Jiaxun Yang <jiaxun.yang@flygoat.com> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
2022-05-31 18:04:12 +08:00
SYM_CODE_END(smpboot_entry)
#endif /* CONFIG_SMP */
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>
2022-05-31 18:04:11 +08:00
SYM_ENTRY(kernel_entry_end, SYM_L_GLOBAL, SYM_A_NONE)
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