[PATCH v3 1/7] kexec: add KEXEC_ELF
Sven Schnelle
svens at stackframe.org
Thu Jul 11 00:29:38 AEST 2019
Right now powerpc provides an implementation to read elf files
with the kexec_file() syscall. Make that available as a public
kexec interface so it can be re-used on other architectures.
Signed-off-by: Sven Schnelle <svens at stackframe.org>
---
arch/Kconfig | 3 +
arch/powerpc/Kconfig | 1 +
arch/powerpc/kernel/kexec_elf_64.c | 551 +-----------------
include/linux/kexec.h | 24 +
kernel/Makefile | 1 +
.../kexec_elf_64.c => kernel/kexec_elf.c | 199 ++-----
6 files changed, 75 insertions(+), 704 deletions(-)
copy arch/powerpc/kernel/kexec_elf_64.c => kernel/kexec_elf.c (71%)
diff --git a/arch/Kconfig b/arch/Kconfig
index c47b328eada0..30694aca4316 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -18,6 +18,9 @@ config KEXEC_CORE
select CRASH_CORE
bool
+config KEXEC_ELF
+ bool
+
config HAVE_IMA_KEXEC
bool
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 12cee37f15c4..addc2dad78e0 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -510,6 +510,7 @@ config KEXEC_FILE
select KEXEC_CORE
select HAVE_IMA_KEXEC
select BUILD_BIN2C
+ select KEXEC_ELF
depends on PPC64
depends on CRYPTO=y
depends on CRYPTO_SHA256=y
diff --git a/arch/powerpc/kernel/kexec_elf_64.c b/arch/powerpc/kernel/kexec_elf_64.c
index ba4f18a43ee8..30bd57a93c17 100644
--- a/arch/powerpc/kernel/kexec_elf_64.c
+++ b/arch/powerpc/kernel/kexec_elf_64.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
/*
* Load ELF vmlinux file for the kexec_file_load syscall.
*
@@ -10,15 +11,6 @@
* Based on kexec-tools' kexec-elf-exec.c and kexec-elf-ppc64.c.
* Heavily modified for the kernel by
* Thiago Jung Bauermann <bauerman at linux.vnet.ibm.com>.
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation (version 2 of the License).
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
*/
#define pr_fmt(fmt) "kexec_elf: " fmt
@@ -39,532 +31,6 @@
#define Elf_Rel Elf64_Rel
#endif /* Elf_Rel */
-struct elf_info {
- /*
- * Where the ELF binary contents are kept.
- * Memory managed by the user of the struct.
- */
- const char *buffer;
-
- const struct elfhdr *ehdr;
- const struct elf_phdr *proghdrs;
- struct elf_shdr *sechdrs;
-};
-
-static inline bool elf_is_elf_file(const struct elfhdr *ehdr)
-{
- return memcmp(ehdr->e_ident, ELFMAG, SELFMAG) == 0;
-}
-
-static uint64_t elf64_to_cpu(const struct elfhdr *ehdr, uint64_t value)
-{
- if (ehdr->e_ident[EI_DATA] == ELFDATA2LSB)
- value = le64_to_cpu(value);
- else if (ehdr->e_ident[EI_DATA] == ELFDATA2MSB)
- value = be64_to_cpu(value);
-
- return value;
-}
-
-static uint16_t elf16_to_cpu(const struct elfhdr *ehdr, uint16_t value)
-{
- if (ehdr->e_ident[EI_DATA] == ELFDATA2LSB)
- value = le16_to_cpu(value);
- else if (ehdr->e_ident[EI_DATA] == ELFDATA2MSB)
- value = be16_to_cpu(value);
-
- return value;
-}
-
-static uint32_t elf32_to_cpu(const struct elfhdr *ehdr, uint32_t value)
-{
- if (ehdr->e_ident[EI_DATA] == ELFDATA2LSB)
- value = le32_to_cpu(value);
- else if (ehdr->e_ident[EI_DATA] == ELFDATA2MSB)
- value = be32_to_cpu(value);
-
- return value;
-}
-
-/**
- * elf_is_ehdr_sane - check that it is safe to use the ELF header
- * @buf_len: size of the buffer in which the ELF file is loaded.
- */
-static bool elf_is_ehdr_sane(const struct elfhdr *ehdr, size_t buf_len)
-{
- if (ehdr->e_phnum > 0 && ehdr->e_phentsize != sizeof(struct elf_phdr)) {
- pr_debug("Bad program header size.\n");
- return false;
- } else if (ehdr->e_shnum > 0 &&
- ehdr->e_shentsize != sizeof(struct elf_shdr)) {
- pr_debug("Bad section header size.\n");
- return false;
- } else if (ehdr->e_ident[EI_VERSION] != EV_CURRENT ||
- ehdr->e_version != EV_CURRENT) {
- pr_debug("Unknown ELF version.\n");
- return false;
- }
-
- if (ehdr->e_phoff > 0 && ehdr->e_phnum > 0) {
- size_t phdr_size;
-
- /*
- * e_phnum is at most 65535 so calculating the size of the
- * program header cannot overflow.
- */
- phdr_size = sizeof(struct elf_phdr) * ehdr->e_phnum;
-
- /* Sanity check the program header table location. */
- if (ehdr->e_phoff + phdr_size < ehdr->e_phoff) {
- pr_debug("Program headers at invalid location.\n");
- return false;
- } else if (ehdr->e_phoff + phdr_size > buf_len) {
- pr_debug("Program headers truncated.\n");
- return false;
- }
- }
-
- if (ehdr->e_shoff > 0 && ehdr->e_shnum > 0) {
- size_t shdr_size;
-
- /*
- * e_shnum is at most 65536 so calculating
- * the size of the section header cannot overflow.
- */
- shdr_size = sizeof(struct elf_shdr) * ehdr->e_shnum;
-
- /* Sanity check the section header table location. */
- if (ehdr->e_shoff + shdr_size < ehdr->e_shoff) {
- pr_debug("Section headers at invalid location.\n");
- return false;
- } else if (ehdr->e_shoff + shdr_size > buf_len) {
- pr_debug("Section headers truncated.\n");
- return false;
- }
- }
-
- return true;
-}
-
-static int elf_read_ehdr(const char *buf, size_t len, struct elfhdr *ehdr)
-{
- struct elfhdr *buf_ehdr;
-
- if (len < sizeof(*buf_ehdr)) {
- pr_debug("Buffer is too small to hold ELF header.\n");
- return -ENOEXEC;
- }
-
- memset(ehdr, 0, sizeof(*ehdr));
- memcpy(ehdr->e_ident, buf, sizeof(ehdr->e_ident));
- if (!elf_is_elf_file(ehdr)) {
- pr_debug("No ELF header magic.\n");
- return -ENOEXEC;
- }
-
- if (ehdr->e_ident[EI_CLASS] != ELF_CLASS) {
- pr_debug("Not a supported ELF class.\n");
- return -ENOEXEC;
- } else if (ehdr->e_ident[EI_DATA] != ELFDATA2LSB &&
- ehdr->e_ident[EI_DATA] != ELFDATA2MSB) {
- pr_debug("Not a supported ELF data format.\n");
- return -ENOEXEC;
- }
-
- buf_ehdr = (struct elfhdr *) buf;
- if (elf16_to_cpu(ehdr, buf_ehdr->e_ehsize) != sizeof(*buf_ehdr)) {
- pr_debug("Bad ELF header size.\n");
- return -ENOEXEC;
- }
-
- ehdr->e_type = elf16_to_cpu(ehdr, buf_ehdr->e_type);
- ehdr->e_machine = elf16_to_cpu(ehdr, buf_ehdr->e_machine);
- ehdr->e_version = elf32_to_cpu(ehdr, buf_ehdr->e_version);
- ehdr->e_entry = elf_addr_to_cpu(ehdr, buf_ehdr->e_entry);
- ehdr->e_phoff = elf_addr_to_cpu(ehdr, buf_ehdr->e_phoff);
- ehdr->e_shoff = elf_addr_to_cpu(ehdr, buf_ehdr->e_shoff);
- ehdr->e_flags = elf32_to_cpu(ehdr, buf_ehdr->e_flags);
- ehdr->e_phentsize = elf16_to_cpu(ehdr, buf_ehdr->e_phentsize);
- ehdr->e_phnum = elf16_to_cpu(ehdr, buf_ehdr->e_phnum);
- ehdr->e_shentsize = elf16_to_cpu(ehdr, buf_ehdr->e_shentsize);
- ehdr->e_shnum = elf16_to_cpu(ehdr, buf_ehdr->e_shnum);
- ehdr->e_shstrndx = elf16_to_cpu(ehdr, buf_ehdr->e_shstrndx);
-
- return elf_is_ehdr_sane(ehdr, len) ? 0 : -ENOEXEC;
-}
-
-/**
- * elf_is_phdr_sane - check that it is safe to use the program header
- * @buf_len: size of the buffer in which the ELF file is loaded.
- */
-static bool elf_is_phdr_sane(const struct elf_phdr *phdr, size_t buf_len)
-{
-
- if (phdr->p_offset + phdr->p_filesz < phdr->p_offset) {
- pr_debug("ELF segment location wraps around.\n");
- return false;
- } else if (phdr->p_offset + phdr->p_filesz > buf_len) {
- pr_debug("ELF segment not in file.\n");
- return false;
- } else if (phdr->p_paddr + phdr->p_memsz < phdr->p_paddr) {
- pr_debug("ELF segment address wraps around.\n");
- return false;
- }
-
- return true;
-}
-
-static int elf_read_phdr(const char *buf, size_t len, struct elf_info *elf_info,
- int idx)
-{
- /* Override the const in proghdrs, we are the ones doing the loading. */
- struct elf_phdr *phdr = (struct elf_phdr *) &elf_info->proghdrs[idx];
- const char *pbuf;
- struct elf_phdr *buf_phdr;
-
- pbuf = buf + elf_info->ehdr->e_phoff + (idx * sizeof(*buf_phdr));
- buf_phdr = (struct elf_phdr *) pbuf;
-
- phdr->p_type = elf32_to_cpu(elf_info->ehdr, buf_phdr->p_type);
- phdr->p_offset = elf_addr_to_cpu(elf_info->ehdr, buf_phdr->p_offset);
- phdr->p_paddr = elf_addr_to_cpu(elf_info->ehdr, buf_phdr->p_paddr);
- phdr->p_vaddr = elf_addr_to_cpu(elf_info->ehdr, buf_phdr->p_vaddr);
- phdr->p_flags = elf32_to_cpu(elf_info->ehdr, buf_phdr->p_flags);
-
- /*
- * The following fields have a type equivalent to Elf_Addr
- * both in 32 bit and 64 bit ELF.
- */
- phdr->p_filesz = elf_addr_to_cpu(elf_info->ehdr, buf_phdr->p_filesz);
- phdr->p_memsz = elf_addr_to_cpu(elf_info->ehdr, buf_phdr->p_memsz);
- phdr->p_align = elf_addr_to_cpu(elf_info->ehdr, buf_phdr->p_align);
-
- return elf_is_phdr_sane(phdr, len) ? 0 : -ENOEXEC;
-}
-
-/**
- * elf_read_phdrs - read the program headers from the buffer
- *
- * This function assumes that the program header table was checked for sanity.
- * Use elf_is_ehdr_sane() if it wasn't.
- */
-static int elf_read_phdrs(const char *buf, size_t len,
- struct elf_info *elf_info)
-{
- size_t phdr_size, i;
- const struct elfhdr *ehdr = elf_info->ehdr;
-
- /*
- * e_phnum is at most 65535 so calculating the size of the
- * program header cannot overflow.
- */
- phdr_size = sizeof(struct elf_phdr) * ehdr->e_phnum;
-
- elf_info->proghdrs = kzalloc(phdr_size, GFP_KERNEL);
- if (!elf_info->proghdrs)
- return -ENOMEM;
-
- for (i = 0; i < ehdr->e_phnum; i++) {
- int ret;
-
- ret = elf_read_phdr(buf, len, elf_info, i);
- if (ret) {
- kfree(elf_info->proghdrs);
- elf_info->proghdrs = NULL;
- return ret;
- }
- }
-
- return 0;
-}
-
-/**
- * elf_is_shdr_sane - check that it is safe to use the section header
- * @buf_len: size of the buffer in which the ELF file is loaded.
- */
-static bool elf_is_shdr_sane(const struct elf_shdr *shdr, size_t buf_len)
-{
- bool size_ok;
-
- /* SHT_NULL headers have undefined values, so we can't check them. */
- if (shdr->sh_type == SHT_NULL)
- return true;
-
- /* Now verify sh_entsize */
- switch (shdr->sh_type) {
- case SHT_SYMTAB:
- size_ok = shdr->sh_entsize == sizeof(Elf_Sym);
- break;
- case SHT_RELA:
- size_ok = shdr->sh_entsize == sizeof(Elf_Rela);
- break;
- case SHT_DYNAMIC:
- size_ok = shdr->sh_entsize == sizeof(Elf_Dyn);
- break;
- case SHT_REL:
- size_ok = shdr->sh_entsize == sizeof(Elf_Rel);
- break;
- case SHT_NOTE:
- case SHT_PROGBITS:
- case SHT_HASH:
- case SHT_NOBITS:
- default:
- /*
- * This is a section whose entsize requirements
- * I don't care about. If I don't know about
- * the section I can't care about it's entsize
- * requirements.
- */
- size_ok = true;
- break;
- }
-
- if (!size_ok) {
- pr_debug("ELF section with wrong entry size.\n");
- return false;
- } else if (shdr->sh_addr + shdr->sh_size < shdr->sh_addr) {
- pr_debug("ELF section address wraps around.\n");
- return false;
- }
-
- if (shdr->sh_type != SHT_NOBITS) {
- if (shdr->sh_offset + shdr->sh_size < shdr->sh_offset) {
- pr_debug("ELF section location wraps around.\n");
- return false;
- } else if (shdr->sh_offset + shdr->sh_size > buf_len) {
- pr_debug("ELF section not in file.\n");
- return false;
- }
- }
-
- return true;
-}
-
-static int elf_read_shdr(const char *buf, size_t len, struct elf_info *elf_info,
- int idx)
-{
- struct elf_shdr *shdr = &elf_info->sechdrs[idx];
- const struct elfhdr *ehdr = elf_info->ehdr;
- const char *sbuf;
- struct elf_shdr *buf_shdr;
-
- sbuf = buf + ehdr->e_shoff + idx * sizeof(*buf_shdr);
- buf_shdr = (struct elf_shdr *) sbuf;
-
- shdr->sh_name = elf32_to_cpu(ehdr, buf_shdr->sh_name);
- shdr->sh_type = elf32_to_cpu(ehdr, buf_shdr->sh_type);
- shdr->sh_addr = elf_addr_to_cpu(ehdr, buf_shdr->sh_addr);
- shdr->sh_offset = elf_addr_to_cpu(ehdr, buf_shdr->sh_offset);
- shdr->sh_link = elf32_to_cpu(ehdr, buf_shdr->sh_link);
- shdr->sh_info = elf32_to_cpu(ehdr, buf_shdr->sh_info);
-
- /*
- * The following fields have a type equivalent to Elf_Addr
- * both in 32 bit and 64 bit ELF.
- */
- shdr->sh_flags = elf_addr_to_cpu(ehdr, buf_shdr->sh_flags);
- shdr->sh_size = elf_addr_to_cpu(ehdr, buf_shdr->sh_size);
- shdr->sh_addralign = elf_addr_to_cpu(ehdr, buf_shdr->sh_addralign);
- shdr->sh_entsize = elf_addr_to_cpu(ehdr, buf_shdr->sh_entsize);
-
- return elf_is_shdr_sane(shdr, len) ? 0 : -ENOEXEC;
-}
-
-/**
- * elf_read_shdrs - read the section headers from the buffer
- *
- * This function assumes that the section header table was checked for sanity.
- * Use elf_is_ehdr_sane() if it wasn't.
- */
-static int elf_read_shdrs(const char *buf, size_t len,
- struct elf_info *elf_info)
-{
- size_t shdr_size, i;
-
- /*
- * e_shnum is at most 65536 so calculating
- * the size of the section header cannot overflow.
- */
- shdr_size = sizeof(struct elf_shdr) * elf_info->ehdr->e_shnum;
-
- elf_info->sechdrs = kzalloc(shdr_size, GFP_KERNEL);
- if (!elf_info->sechdrs)
- return -ENOMEM;
-
- for (i = 0; i < elf_info->ehdr->e_shnum; i++) {
- int ret;
-
- ret = elf_read_shdr(buf, len, elf_info, i);
- if (ret) {
- kfree(elf_info->sechdrs);
- elf_info->sechdrs = NULL;
- return ret;
- }
- }
-
- return 0;
-}
-
-/**
- * elf_read_from_buffer - read ELF file and sets up ELF header and ELF info
- * @buf: Buffer to read ELF file from.
- * @len: Size of @buf.
- * @ehdr: Pointer to existing struct which will be populated.
- * @elf_info: Pointer to existing struct which will be populated.
- *
- * This function allows reading ELF files with different byte order than
- * the kernel, byte-swapping the fields as needed.
- *
- * Return:
- * On success returns 0, and the caller should call elf_free_info(elf_info) to
- * free the memory allocated for the section and program headers.
- */
-int elf_read_from_buffer(const char *buf, size_t len, struct elfhdr *ehdr,
- struct elf_info *elf_info)
-{
- int ret;
-
- ret = elf_read_ehdr(buf, len, ehdr);
- if (ret)
- return ret;
-
- elf_info->buffer = buf;
- elf_info->ehdr = ehdr;
- if (ehdr->e_phoff > 0 && ehdr->e_phnum > 0) {
- ret = elf_read_phdrs(buf, len, elf_info);
- if (ret)
- return ret;
- }
- if (ehdr->e_shoff > 0 && ehdr->e_shnum > 0) {
- ret = elf_read_shdrs(buf, len, elf_info);
- if (ret) {
- kfree(elf_info->proghdrs);
- return ret;
- }
- }
-
- return 0;
-}
-
-/**
- * elf_free_info - free memory allocated by elf_read_from_buffer
- */
-void elf_free_info(struct elf_info *elf_info)
-{
- kfree(elf_info->proghdrs);
- kfree(elf_info->sechdrs);
- memset(elf_info, 0, sizeof(*elf_info));
-}
-/**
- * build_elf_exec_info - read ELF executable and check that we can use it
- */
-static int build_elf_exec_info(const char *buf, size_t len, struct elfhdr *ehdr,
- struct elf_info *elf_info)
-{
- int i;
- int ret;
-
- ret = elf_read_from_buffer(buf, len, ehdr, elf_info);
- if (ret)
- return ret;
-
- /* Big endian vmlinux has type ET_DYN. */
- if (ehdr->e_type != ET_EXEC && ehdr->e_type != ET_DYN) {
- pr_err("Not an ELF executable.\n");
- goto error;
- } else if (!elf_info->proghdrs) {
- pr_err("No ELF program header.\n");
- goto error;
- }
-
- for (i = 0; i < ehdr->e_phnum; i++) {
- /*
- * Kexec does not support loading interpreters.
- * In addition this check keeps us from attempting
- * to kexec ordinay executables.
- */
- if (elf_info->proghdrs[i].p_type == PT_INTERP) {
- pr_err("Requires an ELF interpreter.\n");
- goto error;
- }
- }
-
- return 0;
-error:
- elf_free_info(elf_info);
- return -ENOEXEC;
-}
-
-static int elf64_probe(const char *buf, unsigned long len)
-{
- struct elfhdr ehdr;
- struct elf_info elf_info;
- int ret;
-
- ret = build_elf_exec_info(buf, len, &ehdr, &elf_info);
- if (ret)
- return ret;
-
- elf_free_info(&elf_info);
-
- return elf_check_arch(&ehdr) ? 0 : -ENOEXEC;
-}
-
-/**
- * elf_exec_load - load ELF executable image
- * @lowest_load_addr: On return, will be the address where the first PT_LOAD
- * section will be loaded in memory.
- *
- * Return:
- * 0 on success, negative value on failure.
- */
-static int elf_exec_load(struct kimage *image, struct elfhdr *ehdr,
- struct elf_info *elf_info,
- unsigned long *lowest_load_addr)
-{
- unsigned long base = 0, lowest_addr = UINT_MAX;
- int ret;
- size_t i;
- struct kexec_buf kbuf = { .image = image, .buf_max = ppc64_rma_size,
- .top_down = false };
-
- /* Read in the PT_LOAD segments. */
- for (i = 0; i < ehdr->e_phnum; i++) {
- unsigned long load_addr;
- size_t size;
- const struct elf_phdr *phdr;
-
- 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.memsz = phdr->p_memsz;
- kbuf.buf_align = phdr->p_align;
- kbuf.buf_min = phdr->p_paddr + base;
- ret = kexec_add_buffer(&kbuf);
- if (ret)
- goto out;
- load_addr = kbuf.mem;
-
- if (load_addr < lowest_addr)
- lowest_addr = load_addr;
- }
-
- /* Update entry point to reflect new load address. */
- ehdr->e_entry += base;
-
- *lowest_load_addr = lowest_addr;
- ret = 0;
- out:
- return ret;
-}
-
static void *elf64_load(struct kimage *image, char *kernel_buf,
unsigned long kernel_len, char *initrd,
unsigned long initrd_len, char *cmdline,
@@ -577,17 +43,18 @@ static void *elf64_load(struct kimage *image, char *kernel_buf,
void *fdt;
const void *slave_code;
struct elfhdr ehdr;
- struct elf_info elf_info;
+ struct kexec_elf_info elf_info;
struct kexec_buf kbuf = { .image = image, .buf_min = 0,
.buf_max = ppc64_rma_size };
struct kexec_buf pbuf = { .image = image, .buf_min = 0,
- .buf_max = ppc64_rma_size, .top_down = true };
+ .buf_max = ppc64_rma_size, .top_down = true,
+ .mem = KEXEC_BUF_MEM_UNKNOWN };
- ret = build_elf_exec_info(kernel_buf, kernel_len, &ehdr, &elf_info);
+ ret = kexec_build_elf_info(kernel_buf, kernel_len, &ehdr, &elf_info);
if (ret)
goto out;
- ret = elf_exec_load(image, &ehdr, &elf_info, &kernel_load_addr);
+ ret = kexec_elf_load(image, &ehdr, &elf_info, &kbuf, &kernel_load_addr);
if (ret)
goto out;
@@ -606,6 +73,7 @@ static void *elf64_load(struct kimage *image, char *kernel_buf,
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;
@@ -638,6 +106,7 @@ static void *elf64_load(struct kimage *image, char *kernel_buf,
kbuf.bufsz = kbuf.memsz = fdt_size;
kbuf.buf_align = PAGE_SIZE;
kbuf.top_down = true;
+ kbuf.mem = KEXEC_BUF_MEM_UNKNOWN;
ret = kexec_add_buffer(&kbuf);
if (ret)
goto out;
@@ -652,13 +121,13 @@ static void *elf64_load(struct kimage *image, char *kernel_buf,
pr_err("Error setting up the purgatory.\n");
out:
- elf_free_info(&elf_info);
+ kexec_free_elf_info(&elf_info);
/* Make kimage_file_post_load_cleanup free the fdt buffer for us. */
return ret ? ERR_PTR(ret) : fdt;
}
const struct kexec_file_ops kexec_elf64_ops = {
- .probe = elf64_probe,
+ .probe = kexec_elf_probe,
.load = elf64_load,
};
diff --git a/include/linux/kexec.h b/include/linux/kexec.h
index b9b1bc5f9669..da2a6b1d69e7 100644
--- a/include/linux/kexec.h
+++ b/include/linux/kexec.h
@@ -216,6 +216,30 @@ extern int crash_prepare_elf64_headers(struct crash_mem *mem, int kernel_map,
void **addr, unsigned long *sz);
#endif /* CONFIG_KEXEC_FILE */
+#ifdef CONFIG_KEXEC_ELF
+struct kexec_elf_info {
+ /*
+ * Where the ELF binary contents are kept.
+ * Memory managed by the user of the struct.
+ */
+ const char *buffer;
+
+ const struct elfhdr *ehdr;
+ const struct elf_phdr *proghdrs;
+ struct elf_shdr *sechdrs;
+};
+
+int kexec_build_elf_info(const char *buf, size_t len, struct elfhdr *ehdr,
+ struct kexec_elf_info *elf_info);
+
+int kexec_elf_load(struct kimage *image, struct elfhdr *ehdr,
+ struct kexec_elf_info *elf_info,
+ struct kexec_buf *kbuf,
+ unsigned long *lowest_load_addr);
+
+void kexec_free_elf_info(struct kexec_elf_info *elf_info);
+int kexec_elf_probe(const char *buf, unsigned long len);
+#endif
struct kimage {
kimage_entry_t head;
kimage_entry_t *entry;
diff --git a/kernel/Makefile b/kernel/Makefile
index 33824f0385b3..7062306de9b7 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -64,6 +64,7 @@ obj-$(CONFIG_CRASH_CORE) += crash_core.o
obj-$(CONFIG_KEXEC_CORE) += kexec_core.o
obj-$(CONFIG_KEXEC) += kexec.o
obj-$(CONFIG_KEXEC_FILE) += kexec_file.o
+obj-$(CONFIG_KEXEC_ELF) += kexec_elf.o
obj-$(CONFIG_BACKTRACE_SELF_TEST) += backtracetest.o
obj-$(CONFIG_COMPAT) += compat.o
obj-$(CONFIG_CGROUPS) += cgroup/
diff --git a/arch/powerpc/kernel/kexec_elf_64.c b/kernel/kexec_elf.c
similarity index 71%
copy from arch/powerpc/kernel/kexec_elf_64.c
copy to kernel/kexec_elf.c
index ba4f18a43ee8..6e9f52171ede 100644
--- a/arch/powerpc/kernel/kexec_elf_64.c
+++ b/kernel/kexec_elf.c
@@ -1,33 +1,10 @@
-/*
- * Load ELF vmlinux file for the kexec_file_load syscall.
- *
- * Copyright (C) 2004 Adam Litke (agl at us.ibm.com)
- * Copyright (C) 2004 IBM Corp.
- * Copyright (C) 2005 R Sharada (sharada at in.ibm.com)
- * Copyright (C) 2006 Mohan Kumar M (mohan at in.ibm.com)
- * Copyright (C) 2016 IBM Corporation
- *
- * Based on kexec-tools' kexec-elf-exec.c and kexec-elf-ppc64.c.
- * Heavily modified for the kernel by
- * Thiago Jung Bauermann <bauerman at linux.vnet.ibm.com>.
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation (version 2 of the License).
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- */
+// SPDX-License-Identifier: GPL-2.0-only
#define pr_fmt(fmt) "kexec_elf: " fmt
#include <linux/elf.h>
#include <linux/kexec.h>
-#include <linux/libfdt.h>
#include <linux/module.h>
-#include <linux/of_fdt.h>
#include <linux/slab.h>
#include <linux/types.h>
@@ -39,21 +16,9 @@
#define Elf_Rel Elf64_Rel
#endif /* Elf_Rel */
-struct elf_info {
- /*
- * Where the ELF binary contents are kept.
- * Memory managed by the user of the struct.
- */
- const char *buffer;
-
- const struct elfhdr *ehdr;
- const struct elf_phdr *proghdrs;
- struct elf_shdr *sechdrs;
-};
-
static inline bool elf_is_elf_file(const struct elfhdr *ehdr)
{
- return memcmp(ehdr->e_ident, ELFMAG, SELFMAG) == 0;
+ return memcmp(ehdr->e_ident, ELFMAG, SELFMAG) == 0;
}
static uint64_t elf64_to_cpu(const struct elfhdr *ehdr, uint64_t value)
@@ -214,7 +179,8 @@ static bool elf_is_phdr_sane(const struct elf_phdr *phdr, size_t buf_len)
return true;
}
-static int elf_read_phdr(const char *buf, size_t len, struct elf_info *elf_info,
+static int elf_read_phdr(const char *buf, size_t len,
+ struct kexec_elf_info *elf_info,
int idx)
{
/* Override the const in proghdrs, we are the ones doing the loading. */
@@ -249,7 +215,7 @@ static int elf_read_phdr(const char *buf, size_t len, struct elf_info *elf_info,
* Use elf_is_ehdr_sane() if it wasn't.
*/
static int elf_read_phdrs(const char *buf, size_t len,
- struct elf_info *elf_info)
+ struct kexec_elf_info *elf_info)
{
size_t phdr_size, i;
const struct elfhdr *ehdr = elf_info->ehdr;
@@ -340,7 +306,8 @@ static bool elf_is_shdr_sane(const struct elf_shdr *shdr, size_t buf_len)
return true;
}
-static int elf_read_shdr(const char *buf, size_t len, struct elf_info *elf_info,
+static int elf_read_shdr(const char *buf, size_t len,
+ struct kexec_elf_info *elf_info,
int idx)
{
struct elf_shdr *shdr = &elf_info->sechdrs[idx];
@@ -377,7 +344,7 @@ static int elf_read_shdr(const char *buf, size_t len, struct elf_info *elf_info,
* Use elf_is_ehdr_sane() if it wasn't.
*/
static int elf_read_shdrs(const char *buf, size_t len,
- struct elf_info *elf_info)
+ struct kexec_elf_info *elf_info)
{
size_t shdr_size, i;
@@ -416,11 +383,13 @@ static int elf_read_shdrs(const char *buf, size_t len,
* the kernel, byte-swapping the fields as needed.
*
* Return:
- * On success returns 0, and the caller should call elf_free_info(elf_info) to
- * free the memory allocated for the section and program headers.
+ * On success returns 0, and the caller should call
+ * kexec_free_elf_info(elf_info) to free the memory allocated for the section
+ * and program headers.
*/
-int elf_read_from_buffer(const char *buf, size_t len, struct elfhdr *ehdr,
- struct elf_info *elf_info)
+static int elf_read_from_buffer(const char *buf, size_t len,
+ struct elfhdr *ehdr,
+ struct kexec_elf_info *elf_info)
{
int ret;
@@ -447,19 +416,19 @@ int elf_read_from_buffer(const char *buf, size_t len, struct elfhdr *ehdr,
}
/**
- * elf_free_info - free memory allocated by elf_read_from_buffer
+ * kexec_free_elf_info - free memory allocated by elf_read_from_buffer
*/
-void elf_free_info(struct elf_info *elf_info)
+void kexec_free_elf_info(struct kexec_elf_info *elf_info)
{
kfree(elf_info->proghdrs);
kfree(elf_info->sechdrs);
memset(elf_info, 0, sizeof(*elf_info));
}
/**
- * build_elf_exec_info - read ELF executable and check that we can use it
+ * kexec_build_elf_info - read ELF executable and check that we can use it
*/
-static int build_elf_exec_info(const char *buf, size_t len, struct elfhdr *ehdr,
- struct elf_info *elf_info)
+int kexec_build_elf_info(const char *buf, size_t len, struct elfhdr *ehdr,
+ struct kexec_elf_info *elf_info)
{
int i;
int ret;
@@ -491,42 +460,42 @@ static int build_elf_exec_info(const char *buf, size_t len, struct elfhdr *ehdr,
return 0;
error:
- elf_free_info(elf_info);
+ kexec_free_elf_info(elf_info);
return -ENOEXEC;
}
-static int elf64_probe(const char *buf, unsigned long len)
+
+int kexec_elf_probe(const char *buf, unsigned long len)
{
struct elfhdr ehdr;
- struct elf_info elf_info;
+ struct kexec_elf_info elf_info;
int ret;
- ret = build_elf_exec_info(buf, len, &ehdr, &elf_info);
+ ret = kexec_build_elf_info(buf, len, &ehdr, &elf_info);
if (ret)
return ret;
- elf_free_info(&elf_info);
+ kexec_free_elf_info(&elf_info);
return elf_check_arch(&ehdr) ? 0 : -ENOEXEC;
}
/**
- * elf_exec_load - load ELF executable image
+ * kexec_elf_load - load ELF executable image
* @lowest_load_addr: On return, will be the address where the first PT_LOAD
* section will be loaded in memory.
*
* Return:
* 0 on success, negative value on failure.
*/
-static int elf_exec_load(struct kimage *image, struct elfhdr *ehdr,
- struct elf_info *elf_info,
+int kexec_elf_load(struct kimage *image, struct elfhdr *ehdr,
+ struct kexec_elf_info *elf_info,
+ struct kexec_buf *kbuf,
unsigned long *lowest_load_addr)
{
unsigned long base = 0, lowest_addr = UINT_MAX;
int ret;
size_t i;
- struct kexec_buf kbuf = { .image = image, .buf_max = ppc64_rma_size,
- .top_down = false };
/* Read in the PT_LOAD segments. */
for (i = 0; i < ehdr->e_phnum; i++) {
@@ -542,15 +511,15 @@ static int elf_exec_load(struct kimage *image, struct elfhdr *ehdr,
if (size > phdr->p_memsz)
size = phdr->p_memsz;
- kbuf.buffer = (void *) elf_info->buffer + phdr->p_offset;
- kbuf.bufsz = size;
- kbuf.memsz = phdr->p_memsz;
- kbuf.buf_align = phdr->p_align;
- kbuf.buf_min = phdr->p_paddr + base;
- ret = kexec_add_buffer(&kbuf);
+ kbuf->buffer = (void *) elf_info->buffer + phdr->p_offset;
+ kbuf->bufsz = size;
+ kbuf->memsz = phdr->p_memsz;
+ kbuf->buf_align = phdr->p_align;
+ kbuf->buf_min = phdr->p_paddr + base;
+ ret = kexec_add_buffer(kbuf);
if (ret)
goto out;
- load_addr = kbuf.mem;
+ load_addr = kbuf->mem;
if (load_addr < lowest_addr)
lowest_addr = load_addr;
@@ -565,100 +534,4 @@ static int elf_exec_load(struct kimage *image, struct elfhdr *ehdr,
return ret;
}
-static void *elf64_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 int fdt_size;
- unsigned long kernel_load_addr;
- unsigned long initrd_load_addr = 0, fdt_load_addr;
- void *fdt;
- const void *slave_code;
- struct elfhdr ehdr;
- struct elf_info elf_info;
- struct kexec_buf kbuf = { .image = image, .buf_min = 0,
- .buf_max = ppc64_rma_size };
- struct kexec_buf pbuf = { .image = image, .buf_min = 0,
- .buf_max = ppc64_rma_size, .top_down = true };
-
- ret = build_elf_exec_info(kernel_buf, kernel_len, &ehdr, &elf_info);
- if (ret)
- goto out;
-
- ret = elf_exec_load(image, &ehdr, &elf_info, &kernel_load_addr);
- if (ret)
- goto out;
-
- pr_debug("Loaded the kernel at 0x%lx\n", kernel_load_addr);
-
- ret = kexec_load_purgatory(image, &pbuf);
- if (ret) {
- pr_err("Loading purgatory failed.\n");
- goto out;
- }
-
- pr_debug("Loaded purgatory at 0x%lx\n", pbuf.mem);
-
- if (initrd != NULL) {
- kbuf.buffer = initrd;
- kbuf.bufsz = kbuf.memsz = initrd_len;
- kbuf.buf_align = PAGE_SIZE;
- kbuf.top_down = false;
- ret = kexec_add_buffer(&kbuf);
- if (ret)
- goto out;
- initrd_load_addr = kbuf.mem;
-
- pr_debug("Loaded initrd at 0x%lx\n", initrd_load_addr);
- }
-
- fdt_size = fdt_totalsize(initial_boot_params) * 2;
- fdt = kmalloc(fdt_size, GFP_KERNEL);
- if (!fdt) {
- pr_err("Not enough memory for the device tree.\n");
- ret = -ENOMEM;
- goto out;
- }
- ret = fdt_open_into(initial_boot_params, fdt, fdt_size);
- if (ret < 0) {
- pr_err("Error setting up the new device tree.\n");
- ret = -EINVAL;
- goto out;
- }
-
- ret = setup_new_fdt(image, fdt, initrd_load_addr, initrd_len, cmdline);
- if (ret)
- goto out;
-
- fdt_pack(fdt);
-
- kbuf.buffer = fdt;
- kbuf.bufsz = kbuf.memsz = fdt_size;
- kbuf.buf_align = PAGE_SIZE;
- kbuf.top_down = true;
- ret = kexec_add_buffer(&kbuf);
- if (ret)
- goto out;
- fdt_load_addr = kbuf.mem;
-
- pr_debug("Loaded device tree at 0x%lx\n", fdt_load_addr);
-
- slave_code = elf_info.buffer + elf_info.proghdrs[0].p_offset;
- ret = setup_purgatory(image, slave_code, fdt, kernel_load_addr,
- fdt_load_addr);
- if (ret)
- pr_err("Error setting up the purgatory.\n");
-
-out:
- elf_free_info(&elf_info);
-
- /* Make kimage_file_post_load_cleanup free the fdt buffer for us. */
- return ret ? ERR_PTR(ret) : fdt;
-}
-const struct kexec_file_ops kexec_elf64_ops = {
- .probe = elf64_probe,
- .load = elf64_load,
-};
--
2.20.1
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