diff options
author | Palmer Dabbelt <palmer@rivosinc.com> | 2022-05-19 15:18:47 -0700 |
---|---|---|
committer | Palmer Dabbelt <palmer@rivosinc.com> | 2022-05-19 16:26:50 -0700 |
commit | 83a7a614ce584c469bf8abfc2cd539701bd7d4e9 (patch) | |
tree | 0ee08a965ab0cdae1f7c33c511d4e0603ed74a57 /arch | |
parent | 7eb6369d7acfe87df73848b3757c648e8f352b86 (diff) | |
parent | 838b3e28488f702e2b5477b393f009b2639d2b1a (diff) | |
download | linux-83a7a614ce584c469bf8abfc2cd539701bd7d4e9.tar.bz2 |
riscv: kexec: add kexec_file_load() support
This patch set implements kexec_file_load() for RISC-V, which is
currently only allowed on rv64 due to some minor build issues on 32-bit
platforms in the generic code. This allows users to kexec() using an FD
as opposed to a buffer.
Link: https://lore.kernel.org/all/20220408100914.150110-1-lizhengyu3@huawei.com/
* palmer/riscv-kexec_file:
RISC-V: Load purgatory in kexec_file
RISC-V: Add purgatory
RISC-V: Support for kexec_file on panic
RISC-V: Add kexec_file support
RISC-V: use memcpy for kexec_file mode
kexec_file: Fix kexec_file.c build error for riscv platform
Diffstat (limited to 'arch')
-rw-r--r-- | arch/riscv/Kbuild | 2 | ||||
-rw-r--r-- | arch/riscv/Kconfig | 20 | ||||
-rw-r--r-- | arch/riscv/include/asm/kexec.h | 4 | ||||
-rw-r--r-- | arch/riscv/kernel/Makefile | 1 | ||||
-rw-r--r-- | arch/riscv/kernel/elf_kexec.c | 448 | ||||
-rw-r--r-- | arch/riscv/kernel/machine_kexec.c | 4 | ||||
-rw-r--r-- | arch/riscv/kernel/machine_kexec_file.c | 14 | ||||
-rw-r--r-- | arch/riscv/purgatory/.gitignore | 4 | ||||
-rw-r--r-- | arch/riscv/purgatory/Makefile | 95 | ||||
-rw-r--r-- | arch/riscv/purgatory/entry.S | 47 | ||||
-rw-r--r-- | arch/riscv/purgatory/purgatory.c | 45 |
11 files changed, 683 insertions, 1 deletions
diff --git a/arch/riscv/Kbuild b/arch/riscv/Kbuild index fb3397223d52..f562c7343fda 100644 --- a/arch/riscv/Kbuild +++ b/arch/riscv/Kbuild @@ -3,5 +3,7 @@ obj-y += kernel/ mm/ net/ obj-$(CONFIG_BUILTIN_DTB) += boot/dts/ +obj-$(CONFIG_ARCH_HAS_KEXEC_PURGATORY) += purgatory/ + # for cleaning subdir- += boot diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig index cad2d42a77d9..0f1dc11b5d7f 100644 --- a/arch/riscv/Kconfig +++ b/arch/riscv/Kconfig @@ -418,6 +418,26 @@ config KEXEC The name comes from the similarity to the exec system call. +config KEXEC_FILE + bool "kexec file based systmem call" + select KEXEC_CORE + select KEXEC_ELF + select HAVE_IMA_KEXEC if IMA + depends on 64BIT + help + This is new version of kexec system call. This system call is + file based and takes file descriptors as system call argument + for kernel and initramfs as opposed to list of segments as + accepted by previous system call. + + If you don't know what to do here, say Y. + +config ARCH_HAS_KEXEC_PURGATORY + def_bool KEXEC_FILE + select BUILD_BIN2C + depends on CRYPTO=y + depends on CRYPTO_SHA256=y + config CRASH_DUMP bool "Build kdump crash kernel" help diff --git a/arch/riscv/include/asm/kexec.h b/arch/riscv/include/asm/kexec.h index e4e291d40759..206217b23301 100644 --- a/arch/riscv/include/asm/kexec.h +++ b/arch/riscv/include/asm/kexec.h @@ -53,4 +53,8 @@ typedef void (*riscv_kexec_method)(unsigned long first_ind_entry, extern riscv_kexec_method riscv_kexec_norelocate; +#ifdef CONFIG_KEXEC_FILE +extern const struct kexec_file_ops elf_kexec_ops; +#endif + #endif diff --git a/arch/riscv/kernel/Makefile b/arch/riscv/kernel/Makefile index 19e0518d6721..c71d6591d539 100644 --- a/arch/riscv/kernel/Makefile +++ b/arch/riscv/kernel/Makefile @@ -79,6 +79,7 @@ endif obj-$(CONFIG_HOTPLUG_CPU) += cpu-hotplug.o obj-$(CONFIG_KGDB) += kgdb.o obj-$(CONFIG_KEXEC) += kexec_relocate.o crash_save_regs.o machine_kexec.o +obj-$(CONFIG_KEXEC_FILE) += elf_kexec.o machine_kexec_file.o obj-$(CONFIG_CRASH_DUMP) += crash_dump.o obj-$(CONFIG_JUMP_LABEL) += jump_label.o diff --git a/arch/riscv/kernel/elf_kexec.c b/arch/riscv/kernel/elf_kexec.c new file mode 100644 index 000000000000..9cb85095fd45 --- /dev/null +++ b/arch/riscv/kernel/elf_kexec.c @@ -0,0 +1,448 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Load ELF vmlinux file for the kexec_file_load syscall. + * + * Copyright (C) 2021 Huawei Technologies Co, Ltd. + * + * Author: Liao Chang (liaochang1@huawei.com) + * + * Based on kexec-tools' kexec-elf-riscv.c, heavily modified + * for kernel. + */ + +#define pr_fmt(fmt) "kexec_image: " fmt + +#include <linux/elf.h> +#include <linux/kexec.h> +#include <linux/slab.h> +#include <linux/of.h> +#include <linux/libfdt.h> +#include <linux/types.h> +#include <linux/memblock.h> +#include <asm/setup.h> + +static int riscv_kexec_elf_load(struct kimage *image, struct elfhdr *ehdr, + struct kexec_elf_info *elf_info, unsigned long old_pbase, + unsigned long new_pbase) +{ + int i; + int ret = 0; + size_t size; + struct kexec_buf kbuf; + const struct elf_phdr *phdr; + + kbuf.image = image; + + for (i = 0; i < ehdr->e_phnum; i++) { + phdr = &elf_info->proghdrs[i]; + if (phdr->p_type != PT_LOAD) + continue; + + size = phdr->p_filesz; + if (size > phdr->p_memsz) + size = phdr->p_memsz; + + kbuf.buffer = (void *) elf_info->buffer + phdr->p_offset; + kbuf.bufsz = size; + kbuf.buf_align = phdr->p_align; + kbuf.mem = phdr->p_paddr - old_pbase + new_pbase; + kbuf.memsz = phdr->p_memsz; + kbuf.top_down = false; + ret = kexec_add_buffer(&kbuf); + if (ret) + break; + } + + return ret; +} + +/* + * Go through the available phsyical memory regions and find one that hold + * an image of the specified size. + */ +static int elf_find_pbase(struct kimage *image, unsigned long kernel_len, + struct elfhdr *ehdr, struct kexec_elf_info *elf_info, + unsigned long *old_pbase, unsigned long *new_pbase) +{ + int i; + int ret; + struct kexec_buf kbuf; + const struct elf_phdr *phdr; + unsigned long lowest_paddr = ULONG_MAX; + unsigned long lowest_vaddr = ULONG_MAX; + + for (i = 0; i < ehdr->e_phnum; i++) { + phdr = &elf_info->proghdrs[i]; + if (phdr->p_type != PT_LOAD) + continue; + + if (lowest_paddr > phdr->p_paddr) + lowest_paddr = phdr->p_paddr; + + if (lowest_vaddr > phdr->p_vaddr) + lowest_vaddr = phdr->p_vaddr; + } + + kbuf.image = image; + kbuf.buf_min = lowest_paddr; + kbuf.buf_max = ULONG_MAX; + kbuf.buf_align = PAGE_SIZE; + kbuf.mem = KEXEC_BUF_MEM_UNKNOWN; + kbuf.memsz = ALIGN(kernel_len, PAGE_SIZE); + kbuf.top_down = false; + ret = arch_kexec_locate_mem_hole(&kbuf); + if (!ret) { + *old_pbase = lowest_paddr; + *new_pbase = kbuf.mem; + image->start = ehdr->e_entry - lowest_vaddr + kbuf.mem; + } + return ret; +} + +static int get_nr_ram_ranges_callback(struct resource *res, void *arg) +{ + unsigned int *nr_ranges = arg; + + (*nr_ranges)++; + return 0; +} + +static int prepare_elf64_ram_headers_callback(struct resource *res, void *arg) +{ + struct crash_mem *cmem = arg; + + cmem->ranges[cmem->nr_ranges].start = res->start; + cmem->ranges[cmem->nr_ranges].end = res->end; + cmem->nr_ranges++; + + return 0; +} + +static int prepare_elf_headers(void **addr, unsigned long *sz) +{ + struct crash_mem *cmem; + unsigned int nr_ranges; + int ret; + + nr_ranges = 1; /* For exclusion of crashkernel region */ + walk_system_ram_res(0, -1, &nr_ranges, get_nr_ram_ranges_callback); + + cmem = kmalloc(struct_size(cmem, ranges, nr_ranges), GFP_KERNEL); + if (!cmem) + return -ENOMEM; + + cmem->max_nr_ranges = nr_ranges; + cmem->nr_ranges = 0; + ret = walk_system_ram_res(0, -1, cmem, prepare_elf64_ram_headers_callback); + if (ret) + goto out; + + /* Exclude crashkernel region */ + ret = crash_exclude_mem_range(cmem, crashk_res.start, crashk_res.end); + if (!ret) + ret = crash_prepare_elf64_headers(cmem, true, addr, sz); + +out: + kfree(cmem); + return ret; +} + +static char *setup_kdump_cmdline(struct kimage *image, char *cmdline, + unsigned long cmdline_len) +{ + int elfcorehdr_strlen; + char *cmdline_ptr; + + cmdline_ptr = kzalloc(COMMAND_LINE_SIZE, GFP_KERNEL); + if (!cmdline_ptr) + return NULL; + + elfcorehdr_strlen = sprintf(cmdline_ptr, "elfcorehdr=0x%lx ", + image->elf_load_addr); + + if (elfcorehdr_strlen + cmdline_len > COMMAND_LINE_SIZE) { + pr_err("Appending elfcorehdr=<addr> exceeds cmdline size\n"); + kfree(cmdline_ptr); + return NULL; + } + + memcpy(cmdline_ptr + elfcorehdr_strlen, cmdline, cmdline_len); + /* Ensure it's nul terminated */ + cmdline_ptr[COMMAND_LINE_SIZE - 1] = '\0'; + return cmdline_ptr; +} + +static void *elf_kexec_load(struct kimage *image, char *kernel_buf, + unsigned long kernel_len, char *initrd, + unsigned long initrd_len, char *cmdline, + unsigned long cmdline_len) +{ + int ret; + unsigned long old_kernel_pbase = ULONG_MAX; + unsigned long new_kernel_pbase = 0UL; + unsigned long initrd_pbase = 0UL; + unsigned long headers_sz; + unsigned long kernel_start; + void *fdt, *headers; + struct elfhdr ehdr; + struct kexec_buf kbuf; + struct kexec_elf_info elf_info; + char *modified_cmdline = NULL; + + ret = kexec_build_elf_info(kernel_buf, kernel_len, &ehdr, &elf_info); + if (ret) + return ERR_PTR(ret); + + ret = elf_find_pbase(image, kernel_len, &ehdr, &elf_info, + &old_kernel_pbase, &new_kernel_pbase); + if (ret) + goto out; + kernel_start = image->start; + pr_notice("The entry point of kernel at 0x%lx\n", image->start); + + /* Add the kernel binary to the image */ + ret = riscv_kexec_elf_load(image, &ehdr, &elf_info, + old_kernel_pbase, new_kernel_pbase); + if (ret) + goto out; + + kbuf.image = image; + kbuf.buf_min = new_kernel_pbase + kernel_len; + kbuf.buf_max = ULONG_MAX; + + /* Add elfcorehdr */ + if (image->type == KEXEC_TYPE_CRASH) { + ret = prepare_elf_headers(&headers, &headers_sz); + if (ret) { + pr_err("Preparing elf core header failed\n"); + goto out; + } + + kbuf.buffer = headers; + kbuf.bufsz = headers_sz; + kbuf.mem = KEXEC_BUF_MEM_UNKNOWN; + kbuf.memsz = headers_sz; + kbuf.buf_align = ELF_CORE_HEADER_ALIGN; + kbuf.top_down = true; + + ret = kexec_add_buffer(&kbuf); + if (ret) { + vfree(headers); + goto out; + } + image->elf_headers = headers; + image->elf_load_addr = kbuf.mem; + image->elf_headers_sz = headers_sz; + + pr_debug("Loaded elf core header at 0x%lx bufsz=0x%lx memsz=0x%lx\n", + image->elf_load_addr, kbuf.bufsz, kbuf.memsz); + + /* Setup cmdline for kdump kernel case */ + modified_cmdline = setup_kdump_cmdline(image, cmdline, + cmdline_len); + if (!modified_cmdline) { + pr_err("Setting up cmdline for kdump kernel failed\n"); + ret = -EINVAL; + goto out; + } + cmdline = modified_cmdline; + } + +#ifdef CONFIG_ARCH_HAS_KEXEC_PURGATORY + /* Add purgatory to the image */ + kbuf.top_down = true; + kbuf.mem = KEXEC_BUF_MEM_UNKNOWN; + ret = kexec_load_purgatory(image, &kbuf); + if (ret) { + pr_err("Error loading purgatory ret=%d\n", ret); + goto out; + } + ret = kexec_purgatory_get_set_symbol(image, "riscv_kernel_entry", + &kernel_start, + sizeof(kernel_start), 0); + if (ret) + pr_err("Error update purgatory ret=%d\n", ret); +#endif /* CONFIG_ARCH_HAS_KEXEC_PURGATORY */ + + /* Add the initrd to the image */ + if (initrd != NULL) { + kbuf.buffer = initrd; + kbuf.bufsz = kbuf.memsz = initrd_len; + kbuf.buf_align = PAGE_SIZE; + kbuf.top_down = false; + kbuf.mem = KEXEC_BUF_MEM_UNKNOWN; + ret = kexec_add_buffer(&kbuf); + if (ret) + goto out; + initrd_pbase = kbuf.mem; + pr_notice("Loaded initrd at 0x%lx\n", initrd_pbase); + } + + /* Add the DTB to the image */ + fdt = of_kexec_alloc_and_setup_fdt(image, initrd_pbase, + initrd_len, cmdline, 0); + if (!fdt) { + pr_err("Error setting up the new device tree.\n"); + ret = -EINVAL; + goto out; + } + + fdt_pack(fdt); + kbuf.buffer = fdt; + kbuf.bufsz = kbuf.memsz = fdt_totalsize(fdt); + kbuf.buf_align = PAGE_SIZE; + kbuf.mem = KEXEC_BUF_MEM_UNKNOWN; + kbuf.top_down = true; + ret = kexec_add_buffer(&kbuf); + if (ret) { + pr_err("Error add DTB kbuf ret=%d\n", ret); + goto out_free_fdt; + } + pr_notice("Loaded device tree at 0x%lx\n", kbuf.mem); + goto out; + +out_free_fdt: + kvfree(fdt); +out: + kfree(modified_cmdline); + kexec_free_elf_info(&elf_info); + return ret ? ERR_PTR(ret) : NULL; +} + +#define RV_X(x, s, n) (((x) >> (s)) & ((1 << (n)) - 1)) +#define RISCV_IMM_BITS 12 +#define RISCV_IMM_REACH (1LL << RISCV_IMM_BITS) +#define RISCV_CONST_HIGH_PART(x) \ + (((x) + (RISCV_IMM_REACH >> 1)) & ~(RISCV_IMM_REACH - 1)) +#define RISCV_CONST_LOW_PART(x) ((x) - RISCV_CONST_HIGH_PART(x)) + +#define ENCODE_ITYPE_IMM(x) \ + (RV_X(x, 0, 12) << 20) +#define ENCODE_BTYPE_IMM(x) \ + ((RV_X(x, 1, 4) << 8) | (RV_X(x, 5, 6) << 25) | \ + (RV_X(x, 11, 1) << 7) | (RV_X(x, 12, 1) << 31)) +#define ENCODE_UTYPE_IMM(x) \ + (RV_X(x, 12, 20) << 12) +#define ENCODE_JTYPE_IMM(x) \ + ((RV_X(x, 1, 10) << 21) | (RV_X(x, 11, 1) << 20) | \ + (RV_X(x, 12, 8) << 12) | (RV_X(x, 20, 1) << 31)) +#define ENCODE_CBTYPE_IMM(x) \ + ((RV_X(x, 1, 2) << 3) | (RV_X(x, 3, 2) << 10) | (RV_X(x, 5, 1) << 2) | \ + (RV_X(x, 6, 2) << 5) | (RV_X(x, 8, 1) << 12)) +#define ENCODE_CJTYPE_IMM(x) \ + ((RV_X(x, 1, 3) << 3) | (RV_X(x, 4, 1) << 11) | (RV_X(x, 5, 1) << 2) | \ + (RV_X(x, 6, 1) << 7) | (RV_X(x, 7, 1) << 6) | (RV_X(x, 8, 2) << 9) | \ + (RV_X(x, 10, 1) << 8) | (RV_X(x, 11, 1) << 12)) +#define ENCODE_UJTYPE_IMM(x) \ + (ENCODE_UTYPE_IMM(RISCV_CONST_HIGH_PART(x)) | \ + (ENCODE_ITYPE_IMM(RISCV_CONST_LOW_PART(x)) << 32)) +#define ENCODE_UITYPE_IMM(x) \ + (ENCODE_UTYPE_IMM(x) | (ENCODE_ITYPE_IMM(x) << 32)) + +#define CLEAN_IMM(type, x) \ + ((~ENCODE_##type##_IMM((uint64_t)(-1))) & (x)) + +int arch_kexec_apply_relocations_add(struct purgatory_info *pi, + Elf_Shdr *section, + const Elf_Shdr *relsec, + const Elf_Shdr *symtab) +{ + const char *strtab, *name, *shstrtab; + const Elf_Shdr *sechdrs; + Elf_Rela *relas; + int i, r_type; + + /* String & section header string table */ + sechdrs = (void *)pi->ehdr + pi->ehdr->e_shoff; + strtab = (char *)pi->ehdr + sechdrs[symtab->sh_link].sh_offset; + shstrtab = (char *)pi->ehdr + sechdrs[pi->ehdr->e_shstrndx].sh_offset; + + relas = (void *)pi->ehdr + relsec->sh_offset; + + for (i = 0; i < relsec->sh_size / sizeof(*relas); i++) { + const Elf_Sym *sym; /* symbol to relocate */ + unsigned long addr; /* final location after relocation */ + unsigned long val; /* relocated symbol value */ + unsigned long sec_base; /* relocated symbol value */ + void *loc; /* tmp location to modify */ + + sym = (void *)pi->ehdr + symtab->sh_offset; + sym += ELF64_R_SYM(relas[i].r_info); + + if (sym->st_name) + name = strtab + sym->st_name; + else + name = shstrtab + sechdrs[sym->st_shndx].sh_name; + + loc = pi->purgatory_buf; + loc += section->sh_offset; + loc += relas[i].r_offset; + + if (sym->st_shndx == SHN_ABS) + sec_base = 0; + else if (sym->st_shndx >= pi->ehdr->e_shnum) { + pr_err("Invalid section %d for symbol %s\n", + sym->st_shndx, name); + return -ENOEXEC; + } else + sec_base = pi->sechdrs[sym->st_shndx].sh_addr; + + val = sym->st_value; + val += sec_base; + val += relas[i].r_addend; + + addr = section->sh_addr + relas[i].r_offset; + + r_type = ELF64_R_TYPE(relas[i].r_info); + + switch (r_type) { + case R_RISCV_BRANCH: + *(u32 *)loc = CLEAN_IMM(BTYPE, *(u32 *)loc) | + ENCODE_BTYPE_IMM(val - addr); + break; + case R_RISCV_JAL: + *(u32 *)loc = CLEAN_IMM(JTYPE, *(u32 *)loc) | + ENCODE_JTYPE_IMM(val - addr); + break; + /* + * With no R_RISCV_PCREL_LO12_S, R_RISCV_PCREL_LO12_I + * sym is expected to be next to R_RISCV_PCREL_HI20 + * in purgatory relsec. Handle it like R_RISCV_CALL + * sym, instead of searching the whole relsec. + */ + case R_RISCV_PCREL_HI20: + case R_RISCV_CALL: + *(u64 *)loc = CLEAN_IMM(UITYPE, *(u64 *)loc) | + ENCODE_UJTYPE_IMM(val - addr); + break; + case R_RISCV_RVC_BRANCH: + *(u32 *)loc = CLEAN_IMM(CBTYPE, *(u32 *)loc) | + ENCODE_CBTYPE_IMM(val - addr); + break; + case R_RISCV_RVC_JUMP: + *(u32 *)loc = CLEAN_IMM(CJTYPE, *(u32 *)loc) | + ENCODE_CJTYPE_IMM(val - addr); + break; + case R_RISCV_ADD32: + *(u32 *)loc += val; + break; + case R_RISCV_SUB32: + *(u32 *)loc -= val; + break; + /* It has been applied by R_RISCV_PCREL_HI20 sym */ + case R_RISCV_PCREL_LO12_I: + case R_RISCV_ALIGN: + case R_RISCV_RELAX: + break; + default: + pr_err("Unknown rela relocation: %d\n", r_type); + return -ENOEXEC; + } + } + return 0; +} + +const struct kexec_file_ops elf_kexec_ops = { + .probe = kexec_elf_probe, + .load = elf_kexec_load, +}; diff --git a/arch/riscv/kernel/machine_kexec.c b/arch/riscv/kernel/machine_kexec.c index cbef0fc73afa..df8e24559035 100644 --- a/arch/riscv/kernel/machine_kexec.c +++ b/arch/riscv/kernel/machine_kexec.c @@ -65,7 +65,9 @@ machine_kexec_prepare(struct kimage *image) if (image->segment[i].memsz <= sizeof(fdt)) continue; - if (copy_from_user(&fdt, image->segment[i].buf, sizeof(fdt))) + if (image->file_mode) + memcpy(&fdt, image->segment[i].buf, sizeof(fdt)); + else if (copy_from_user(&fdt, image->segment[i].buf, sizeof(fdt))) continue; if (fdt_check_header(&fdt)) diff --git a/arch/riscv/kernel/machine_kexec_file.c b/arch/riscv/kernel/machine_kexec_file.c new file mode 100644 index 000000000000..b0bf8c1722c0 --- /dev/null +++ b/arch/riscv/kernel/machine_kexec_file.c @@ -0,0 +1,14 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * kexec_file for riscv, use vmlinux as the dump-capture kernel image. + * + * Copyright (C) 2021 Huawei Technologies Co, Ltd. + * + * Author: Liao Chang (liaochang1@huawei.com) + */ +#include <linux/kexec.h> + +const struct kexec_file_ops * const kexec_file_loaders[] = { + &elf_kexec_ops, + NULL +}; diff --git a/arch/riscv/purgatory/.gitignore b/arch/riscv/purgatory/.gitignore new file mode 100644 index 000000000000..38d7d1bda4d7 --- /dev/null +++ b/arch/riscv/purgatory/.gitignore @@ -0,0 +1,4 @@ +# SPDX-License-Identifier: GPL-2.0-only +purgatory.chk +purgatory.ro +kexec-purgatory.c diff --git a/arch/riscv/purgatory/Makefile b/arch/riscv/purgatory/Makefile new file mode 100644 index 000000000000..d4df200f7edf --- /dev/null +++ b/arch/riscv/purgatory/Makefile @@ -0,0 +1,95 @@ +# SPDX-License-Identifier: GPL-2.0 +OBJECT_FILES_NON_STANDARD := y + +purgatory-y := purgatory.o sha256.o entry.o string.o ctype.o memcpy.o memset.o + +targets += $(purgatory-y) +PURGATORY_OBJS = $(addprefix $(obj)/,$(purgatory-y)) + +$(obj)/string.o: $(srctree)/lib/string.c FORCE + $(call if_changed_rule,cc_o_c) + +$(obj)/ctype.o: $(srctree)/lib/ctype.c FORCE + $(call if_changed_rule,cc_o_c) + +$(obj)/memcpy.o: $(srctree)/arch/riscv/lib/memcpy.S FORCE + $(call if_changed_rule,as_o_S) + +$(obj)/memset.o: $(srctree)/arch/riscv/lib/memset.S FORCE + $(call if_changed_rule,as_o_S) + +$(obj)/sha256.o: $(srctree)/lib/crypto/sha256.c FORCE + $(call if_changed_rule,cc_o_c) + +CFLAGS_sha256.o := -D__DISABLE_EXPORTS +CFLAGS_string.o := -D__DISABLE_EXPORTS +CFLAGS_ctype.o := -D__DISABLE_EXPORTS + +# When linking purgatory.ro with -r unresolved symbols are not checked, +# also link a purgatory.chk binary without -r to check for unresolved symbols. +PURGATORY_LDFLAGS := -e purgatory_start -z nodefaultlib +LDFLAGS_purgatory.ro := -r $(PURGATORY_LDFLAGS) +LDFLAGS_purgatory.chk := $(PURGATORY_LDFLAGS) +targets += purgatory.ro purgatory.chk + +# Sanitizer, etc. runtimes are unavailable and cannot be linked here. +GCOV_PROFILE := n +KASAN_SANITIZE := n +UBSAN_SANITIZE := n +KCSAN_SANITIZE := n +KCOV_INSTRUMENT := n + +# These are adjustments to the compiler flags used for objects that +# make up the standalone purgatory.ro + +PURGATORY_CFLAGS_REMOVE := -mcmodel=kernel +PURGATORY_CFLAGS := -mcmodel=medany -ffreestanding -fno-zero-initialized-in-bss +PURGATORY_CFLAGS += $(DISABLE_STACKLEAK_PLUGIN) -DDISABLE_BRANCH_PROFILING +PURGATORY_CFLAGS += -fno-stack-protector -g0 + +# Default KBUILD_CFLAGS can have -pg option set when FTRACE is enabled. That +# in turn leaves some undefined symbols like __fentry__ in purgatory and not +# sure how to relocate those. +ifdef CONFIG_FUNCTION_TRACER +PURGATORY_CFLAGS_REMOVE += $(CC_FLAGS_FTRACE) +endif + +ifdef CONFIG_STACKPROTECTOR +PURGATORY_CFLAGS_REMOVE += -fstack-protector +endif + +ifdef CONFIG_STACKPROTECTOR_STRONG +PURGATORY_CFLAGS_REMOVE += -fstack-protector-strong +endif + +CFLAGS_REMOVE_purgatory.o += $(PURGATORY_CFLAGS_REMOVE) +CFLAGS_purgatory.o += $(PURGATORY_CFLAGS) + +CFLAGS_REMOVE_sha256.o += $(PURGATORY_CFLAGS_REMOVE) +CFLAGS_sha256.o += $(PURGATORY_CFLAGS) + +CFLAGS_REMOVE_string.o += $(PURGATORY_CFLAGS_REMOVE) +CFLAGS_string.o += $(PURGATORY_CFLAGS) + +CFLAGS_REMOVE_ctype.o += $(PURGATORY_CFLAGS_REMOVE) +CFLAGS_ctype.o += $(PURGATORY_CFLAGS) + +AFLAGS_REMOVE_entry.o += -Wa,-gdwarf-2 +AFLAGS_REMOVE_memcpy.o += -Wa,-gdwarf-2 +AFLAGS_REMOVE_memset.o += -Wa,-gdwarf-2 + +$(obj)/purgatory.ro: $(PURGATORY_OBJS) FORCE + $(call if_changed,ld) + +$(obj)/purgatory.chk: $(obj)/purgatory.ro FORCE + $(call if_changed,ld) + +targets += kexec-purgatory.c + +quiet_cmd_bin2c = BIN2C $@ + cmd_bin2c = $(objtree)/scripts/bin2c kexec_purgatory < $< > $@ + +$(obj)/kexec-purgatory.c: $(obj)/purgatory.ro $(obj)/purgatory.chk FORCE + $(call if_changed,bin2c) + +obj-$(CONFIG_ARCH_HAS_KEXEC_PURGATORY) += kexec-purgatory.o diff --git a/arch/riscv/purgatory/entry.S b/arch/riscv/purgatory/entry.S new file mode 100644 index 000000000000..0194f4554130 --- /dev/null +++ b/arch/riscv/purgatory/entry.S @@ -0,0 +1,47 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * purgatory: Runs between two kernels + * + * Copyright (C) 2022 Huawei Technologies Co, Ltd. + * + * Author: Li Zhengyu (lizhengyu3@huawei.com) + * + */ + +.macro size, sym:req + .size \sym, . - \sym +.endm + +.text + +.globl purgatory_start +purgatory_start: + + lla sp, .Lstack + mv s0, a0 /* The hartid of the current hart */ + mv s1, a1 /* Phys address of the FDT image */ + + jal purgatory + + /* Start new image. */ + mv a0, s0 + mv a1, s1 + ld a2, riscv_kernel_entry + jr a2 + +size purgatory_start + +.align 4 + .rept 256 + .quad 0 + .endr +.Lstack: + +.data + +.globl riscv_kernel_entry +riscv_kernel_entry: + .quad 0 +size riscv_kernel_entry + +.end diff --git a/arch/riscv/purgatory/purgatory.c b/arch/riscv/purgatory/purgatory.c new file mode 100644 index 000000000000..80596ab5fb62 --- /dev/null +++ b/arch/riscv/purgatory/purgatory.c @@ -0,0 +1,45 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * purgatory: Runs between two kernels + * + * Copyright (C) 2022 Huawei Technologies Co, Ltd. + * + * Author: Li Zhengyu (lizhengyu3@huawei.com) + * + */ + +#include <linux/purgatory.h> +#include <linux/kernel.h> +#include <linux/string.h> +#include <asm/string.h> + +u8 purgatory_sha256_digest[SHA256_DIGEST_SIZE] __section(".kexec-purgatory"); + +struct kexec_sha_region purgatory_sha_regions[KEXEC_SEGMENT_MAX] __section(".kexec-purgatory"); + +static int verify_sha256_digest(void) +{ + struct kexec_sha_region *ptr, *end; + struct sha256_state ss; + u8 digest[SHA256_DIGEST_SIZE]; + + sha256_init(&ss); + end = purgatory_sha_regions + ARRAY_SIZE(purgatory_sha_regions); + for (ptr = purgatory_sha_regions; ptr < end; ptr++) + sha256_update(&ss, (uint8_t *)(ptr->start), ptr->len); + sha256_final(&ss, digest); + if (memcmp(digest, purgatory_sha256_digest, sizeof(digest)) != 0) + return 1; + return 0; +} + +/* workaround for a warning with -Wmissing-prototypes */ +void purgatory(void); + +void purgatory(void) +{ + if (verify_sha256_digest()) + for (;;) + /* loop forever */ + ; +} |