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-rw-r--r--arch/riscv/kernel/elf_kexec.c469
1 files changed, 469 insertions, 0 deletions
diff --git a/arch/riscv/kernel/elf_kexec.c b/arch/riscv/kernel/elf_kexec.c
new file mode 100644
index 000000000..b3b96ff46
--- /dev/null
+++ b/arch/riscv/kernel/elf_kexec.c
@@ -0,0 +1,469 @@
+// 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>
+
+int arch_kimage_file_post_load_cleanup(struct kimage *image)
+{
+ kvfree(image->arch.fdt);
+ image->arch.fdt = NULL;
+
+ vfree(image->elf_headers);
+ image->elf_headers = NULL;
+ image->elf_headers_sz = 0;
+
+ return kexec_image_post_load_cleanup_default(image);
+}
+
+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;
+
+ /*
+ * Current riscv boot protocol requires 2MB alignment for
+ * RV64 and 4MB alignment for RV32
+ *
+ */
+ kbuf.buf_align = PMD_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 = true;
+ 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;
+ }
+ /* Cache the fdt buffer address for memory cleanup */
+ image->arch.fdt = 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;
+ Elf64_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_PLT:
+ 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,
+};
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-01 11:11:15 +0000