diff options
| -rw-r--r-- | arch/loongarch/Kconfig | 11 | ||||
| -rw-r--r-- | arch/loongarch/include/asm/kexec.h | 60 | ||||
| -rw-r--r-- | arch/loongarch/kernel/Makefile | 2 | ||||
| -rw-r--r-- | arch/loongarch/kernel/head.S | 6 | ||||
| -rw-r--r-- | arch/loongarch/kernel/machine_kexec.c | 216 | ||||
| -rw-r--r-- | arch/loongarch/kernel/relocate_kernel.S | 106 |
6 files changed, 400 insertions, 1 deletions
diff --git a/arch/loongarch/Kconfig b/arch/loongarch/Kconfig index cc3ba53242b6..cbbb82b0c4fe 100644 --- a/arch/loongarch/Kconfig +++ b/arch/loongarch/Kconfig @@ -426,6 +426,17 @@ config ARCH_IOREMAP protection support. However, you can enable LoongArch DMW-based ioremap() for better performance. +config KEXEC + bool "Kexec system call" + select KEXEC_CORE + help + kexec is a system call that implements the ability to shutdown your + current kernel, and to start another kernel. It is like a reboot + but it is independent of the system firmware. And like a reboot + you can start any kernel with it, not just Linux. + + The name comes from the similarity to the exec system call. + config SECCOMP bool "Enable seccomp to safely compute untrusted bytecode" depends on PROC_FS diff --git a/arch/loongarch/include/asm/kexec.h b/arch/loongarch/include/asm/kexec.h new file mode 100644 index 000000000000..cf95cd3eb2de --- /dev/null +++ b/arch/loongarch/include/asm/kexec.h @@ -0,0 +1,60 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * kexec.h for kexec + * + * Copyright (C) 2022 Loongson Technology Corporation Limited + */ + +#ifndef _ASM_KEXEC_H +#define _ASM_KEXEC_H + +#include <asm/stacktrace.h> +#include <asm/page.h> + +/* Maximum physical address we can use pages from */ +#define KEXEC_SOURCE_MEMORY_LIMIT (-1UL) +/* Maximum address we can reach in physical address mode */ +#define KEXEC_DESTINATION_MEMORY_LIMIT (-1UL) + /* Maximum address we can use for the control code buffer */ +#define KEXEC_CONTROL_MEMORY_LIMIT (-1UL) + +/* Reserve a page for the control code buffer */ +#define KEXEC_CONTROL_PAGE_SIZE PAGE_SIZE + +/* The native architecture */ +#define KEXEC_ARCH KEXEC_ARCH_LOONGARCH + +static inline void crash_setup_regs(struct pt_regs *newregs, + struct pt_regs *oldregs) +{ + if (oldregs) + memcpy(newregs, oldregs, sizeof(*newregs)); + else + prepare_frametrace(newregs); +} + +#define ARCH_HAS_KIMAGE_ARCH + +struct kimage_arch { + unsigned long efi_boot; + unsigned long cmdline_ptr; + unsigned long systable_ptr; +}; + +typedef void (*do_kexec_t)(unsigned long efi_boot, + unsigned long cmdline_ptr, + unsigned long systable_ptr, + unsigned long start_addr, + unsigned long first_ind_entry); + +struct kimage; +extern const unsigned char relocate_new_kernel[]; +extern const size_t relocate_new_kernel_size; +extern void kexec_reboot(void); + +#ifdef CONFIG_SMP +extern atomic_t kexec_ready_to_reboot; +extern const unsigned char kexec_smp_wait[]; +#endif + +#endif /* !_ASM_KEXEC_H */ diff --git a/arch/loongarch/kernel/Makefile b/arch/loongarch/kernel/Makefile index 7225916dd378..0bad6272a55e 100644 --- a/arch/loongarch/kernel/Makefile +++ b/arch/loongarch/kernel/Makefile @@ -25,6 +25,8 @@ obj-$(CONFIG_NUMA) += numa.o obj-$(CONFIG_MAGIC_SYSRQ) += sysrq.o +obj-$(CONFIG_KEXEC) += machine_kexec.o relocate_kernel.o + obj-$(CONFIG_UNWINDER_GUESS) += unwind_guess.o obj-$(CONFIG_UNWINDER_PROLOGUE) += unwind_prologue.o diff --git a/arch/loongarch/kernel/head.S b/arch/loongarch/kernel/head.S index d32128f1d3c4..97425779ce9f 100644 --- a/arch/loongarch/kernel/head.S +++ b/arch/loongarch/kernel/head.S @@ -21,7 +21,11 @@ _head: .word MZ_MAGIC /* "MZ", MS-DOS header */ - .org 0x3c /* 0x04 ~ 0x3b reserved */ + .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 */ .long pe_header - _head /* Offset to the PE header */ pe_header: diff --git a/arch/loongarch/kernel/machine_kexec.c b/arch/loongarch/kernel/machine_kexec.c new file mode 100644 index 000000000000..d5037573ed66 --- /dev/null +++ b/arch/loongarch/kernel/machine_kexec.c @@ -0,0 +1,216 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * machine_kexec.c for kexec + * + * Copyright (C) 2022 Loongson Technology Corporation Limited + */ +#include <linux/compiler.h> +#include <linux/cpu.h> +#include <linux/kexec.h> +#include <linux/mm.h> +#include <linux/delay.h> +#include <linux/libfdt.h> +#include <linux/of_fdt.h> + +#include <asm/bootinfo.h> +#include <asm/cacheflush.h> +#include <asm/page.h> + +/* 0x100000 ~ 0x200000 is safe */ +#define KEXEC_CONTROL_CODE TO_CACHE(0x100000UL) +#define KEXEC_CMDLINE_ADDR TO_CACHE(0x108000UL) + +static unsigned long reboot_code_buffer; + +#ifdef CONFIG_SMP +static void (*relocated_kexec_smp_wait)(void *); +atomic_t kexec_ready_to_reboot = ATOMIC_INIT(0); +#endif + +static unsigned long efi_boot; +static unsigned long cmdline_ptr; +static unsigned long systable_ptr; +static unsigned long start_addr; +static unsigned long first_ind_entry; + +static void kexec_image_info(const struct kimage *kimage) +{ + unsigned long i; + + pr_debug("kexec kimage info:\n"); + pr_debug("\ttype: %d\n", kimage->type); + pr_debug("\tstart: %lx\n", kimage->start); + pr_debug("\thead: %lx\n", kimage->head); + pr_debug("\tnr_segments: %lu\n", kimage->nr_segments); + + for (i = 0; i < kimage->nr_segments; i++) { + pr_debug("\t segment[%lu]: %016lx - %016lx", i, + kimage->segment[i].mem, + kimage->segment[i].mem + kimage->segment[i].memsz); + pr_debug("\t\t0x%lx bytes, %lu pages\n", + (unsigned long)kimage->segment[i].memsz, + (unsigned long)kimage->segment[i].memsz / PAGE_SIZE); + } +} + +int machine_kexec_prepare(struct kimage *kimage) +{ + int i; + char *bootloader = "kexec"; + void *cmdline_ptr = (void *)KEXEC_CMDLINE_ADDR; + + kexec_image_info(kimage); + + kimage->arch.efi_boot = fw_arg0; + kimage->arch.systable_ptr = fw_arg2; + + /* Find the command line */ + for (i = 0; i < kimage->nr_segments; i++) { + if (!strncmp(bootloader, (char __user *)kimage->segment[i].buf, strlen(bootloader))) { + if (!copy_from_user(cmdline_ptr, kimage->segment[i].buf, COMMAND_LINE_SIZE)) + kimage->arch.cmdline_ptr = (unsigned long)cmdline_ptr; + break; + } + } + + if (!kimage->arch.cmdline_ptr) { + pr_err("Command line not included in the provided image\n"); + return -EINVAL; + } + + /* kexec need a safe page to save reboot_code_buffer */ + kimage->control_code_page = virt_to_page((void *)KEXEC_CONTROL_CODE); + + reboot_code_buffer = (unsigned long)page_address(kimage->control_code_page); + memcpy((void *)reboot_code_buffer, relocate_new_kernel, relocate_new_kernel_size); + +#ifdef CONFIG_SMP + /* All secondary cpus now may jump to kexec_smp_wait cycle */ + relocated_kexec_smp_wait = reboot_code_buffer + (void *)(kexec_smp_wait - relocate_new_kernel); +#endif + + return 0; +} + +void machine_kexec_cleanup(struct kimage *kimage) +{ +} + +void kexec_reboot(void) +{ + do_kexec_t do_kexec = NULL; + + /* + * We know we were online, and there will be no incoming IPIs at + * this point. + */ + set_cpu_online(smp_processor_id(), true); + + /* Ensure remote CPUs observe that we're online before rebooting. */ + smp_mb__after_atomic(); + + /* + * Make sure we get correct instructions written by the + * machine_kexec_prepare() CPU. + */ + __asm__ __volatile__ ("\tibar 0\n"::); + +#ifdef CONFIG_SMP + /* All secondary cpus go to kexec_smp_wait */ + if (smp_processor_id() > 0) { + relocated_kexec_smp_wait(NULL); + unreachable(); + } +#endif + + do_kexec = (void *)reboot_code_buffer; + do_kexec(efi_boot, cmdline_ptr, systable_ptr, start_addr, first_ind_entry); + + unreachable(); +} + + +#ifdef CONFIG_SMP +static void kexec_shutdown_secondary(void *regs) +{ + int cpu = smp_processor_id(); + + if (!cpu_online(cpu)) + return; + + /* We won't be sent IPIs any more. */ + set_cpu_online(cpu, false); + + local_irq_disable(); + while (!atomic_read(&kexec_ready_to_reboot)) + cpu_relax(); + + kexec_reboot(); +} +#endif + +void machine_shutdown(void) +{ + int cpu; + + /* All CPUs go to reboot_code_buffer */ + for_each_possible_cpu(cpu) + if (!cpu_online(cpu)) + cpu_device_up(get_cpu_device(cpu)); + +#ifdef CONFIG_SMP + smp_call_function(kexec_shutdown_secondary, NULL, 0); +#endif +} + +void machine_crash_shutdown(struct pt_regs *regs) +{ +} + +void machine_kexec(struct kimage *image) +{ + unsigned long entry, *ptr; + struct kimage_arch *internal = &image->arch; + + efi_boot = internal->efi_boot; + cmdline_ptr = internal->cmdline_ptr; + systable_ptr = internal->systable_ptr; + + start_addr = (unsigned long)phys_to_virt(image->start); + + first_ind_entry = (unsigned long)phys_to_virt(image->head & PAGE_MASK); + + /* + * The generic kexec code builds a page list with physical + * addresses. they are directly accessible through XKPRANGE + * hence the phys_to_virt() call. + */ + for (ptr = &image->head; (entry = *ptr) && !(entry & IND_DONE); + ptr = (entry & IND_INDIRECTION) ? + phys_to_virt(entry & PAGE_MASK) : ptr + 1) { + if (*ptr & IND_SOURCE || *ptr & IND_INDIRECTION || + *ptr & IND_DESTINATION) + *ptr = (unsigned long) phys_to_virt(*ptr); + } + + /* Mark offline before disabling local irq. */ + set_cpu_online(smp_processor_id(), false); + + /* We do not want to be bothered. */ + local_irq_disable(); + + pr_notice("EFI boot flag 0x%lx\n", efi_boot); + pr_notice("Command line at 0x%lx\n", cmdline_ptr); + pr_notice("System table at 0x%lx\n", systable_ptr); + pr_notice("We will call new kernel at 0x%lx\n", start_addr); + pr_notice("Bye ...\n"); + + /* Make reboot code buffer available to the boot CPU. */ + flush_cache_all(); + +#ifdef CONFIG_SMP + atomic_set(&kexec_ready_to_reboot, 1); +#endif + + kexec_reboot(); +} diff --git a/arch/loongarch/kernel/relocate_kernel.S b/arch/loongarch/kernel/relocate_kernel.S new file mode 100644 index 000000000000..48362f38c6bf --- /dev/null +++ b/arch/loongarch/kernel/relocate_kernel.S @@ -0,0 +1,106 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * relocate_kernel.S for kexec + * + * Copyright (C) 2022 Loongson Technology Corporation Limited + */ + +#include <linux/kexec.h> + +#include <asm/asm.h> +#include <asm/asmmacro.h> +#include <asm/regdef.h> +#include <asm/loongarch.h> +#include <asm/stackframe.h> +#include <asm/addrspace.h> + +SYM_CODE_START(relocate_new_kernel) + /* + * a0: EFI boot flag for the new kernel + * a1: Command line pointer for the new kernel + * a2: System table pointer for the new kernel + * a3: Start address to jump to after relocation + * a4: Pointer to the current indirection page entry + */ + move s0, a4 + +process_entry: + PTR_L s1, s0, 0 + PTR_ADDI s0, s0, SZREG + + /* destination page */ + andi s2, s1, IND_DESTINATION + beqz s2, 1f + li.w t0, ~0x1 + and s3, s1, t0 /* store destination addr in s3 */ + b process_entry + +1: + /* indirection page, update s0 */ + andi s2, s1, IND_INDIRECTION + beqz s2, 1f + li.w t0, ~0x2 + and s0, s1, t0 + b process_entry + +1: + /* done page */ + andi s2, s1, IND_DONE + beqz s2, 1f + b done + +1: + /* source page */ + andi s2, s1, IND_SOURCE + beqz s2, process_entry + li.w t0, ~0x8 + and s1, s1, t0 + li.w s5, (1 << _PAGE_SHIFT) / SZREG + +copy_word: + /* copy page word by word */ + REG_L s4, s1, 0 + REG_S s4, s3, 0 + PTR_ADDI s3, s3, SZREG + PTR_ADDI s1, s1, SZREG + LONG_ADDI s5, s5, -1 + beqz s5, process_entry + b copy_word + b process_entry + +done: + ibar 0 + dbar 0 + + /* + * Jump to the new kernel, + * make sure the values of a0, a1, a2 and a3 are not changed. + */ + jr a3 +SYM_CODE_END(relocate_new_kernel) + +#ifdef CONFIG_SMP +/* + * Other CPUs should wait until code is relocated and + * then start at the entry point from LOONGARCH_IOCSR_MBUF0. + */ +SYM_CODE_START(kexec_smp_wait) +1: li.w t0, 0x100 /* wait for init loop */ +2: addi.w t0, t0, -1 /* limit mailbox access */ + bnez t0, 2b + li.w t1, LOONGARCH_IOCSR_MBUF0 + iocsrrd.w s0, t1 /* check PC as an indicator */ + beqz s0, 1b + iocsrrd.d s0, t1 /* get PC via mailbox */ + + li.d t0, CACHE_BASE + or s0, s0, t0 /* s0 = TO_CACHE(s0) */ + jr s0 /* jump to initial PC */ +SYM_CODE_END(kexec_smp_wait) +#endif + +relocate_new_kernel_end: + +SYM_DATA_START(relocate_new_kernel_size) + PTR relocate_new_kernel_end - relocate_new_kernel +SYM_DATA_END(relocate_new_kernel_size) |