[PATCH v5 7/7] kexec_elf: support 32 bit ELF files
From: Sven Schnelle <hidden>
Date: 2019-08-23 20:51:43
Also in:
kexec
Subsystem:
kexec, the rest · Maintainers:
Andrew Morton, Baoquan He, Mike Rapoport, Pasha Tatashin, Pratyush Yadav, Linus Torvalds
The powerpc version only supported 64 bit. Add some code to switch decoding of fields during runtime so we can kexec a 32 bit kernel from a 64 bit kernel and vice versa. Signed-off-by: Sven Schnelle <redacted> Reviewed-by: Thiago Jung Bauermann <redacted> --- kernel/kexec_elf.c | 57 ++++++++++++++++++++++++++++++++++------------ 1 file changed, 42 insertions(+), 15 deletions(-)
diff --git a/kernel/kexec_elf.c b/kernel/kexec_elf.c
index 85f2bd177d6e..d3689632e8b9 100644
--- a/kernel/kexec_elf.c
+++ b/kernel/kexec_elf.c@@ -21,8 +21,6 @@ #include <linux/slab.h> #include <linux/types.h> -#define elf_addr_to_cpu elf64_to_cpu - static inline bool elf_is_elf_file(const struct elfhdr *ehdr) { return memcmp(ehdr->e_ident, ELFMAG, SELFMAG) == 0;
@@ -152,9 +150,6 @@ static int elf_read_ehdr(const char *buf, size_t len, struct elfhdr *ehdr) 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);
@@ -162,6 +157,24 @@ static int elf_read_ehdr(const char *buf, size_t len, struct elfhdr *ehdr) ehdr->e_shnum = elf16_to_cpu(ehdr, buf_ehdr->e_shnum); ehdr->e_shstrndx = elf16_to_cpu(ehdr, buf_ehdr->e_shstrndx); + switch (ehdr->e_ident[EI_CLASS]) { + case ELFCLASS64: + ehdr->e_entry = elf64_to_cpu(ehdr, buf_ehdr->e_entry); + ehdr->e_phoff = elf64_to_cpu(ehdr, buf_ehdr->e_phoff); + ehdr->e_shoff = elf64_to_cpu(ehdr, buf_ehdr->e_shoff); + break; + + case ELFCLASS32: + ehdr->e_entry = elf32_to_cpu(ehdr, buf_ehdr->e_entry); + ehdr->e_phoff = elf32_to_cpu(ehdr, buf_ehdr->e_phoff); + ehdr->e_shoff = elf32_to_cpu(ehdr, buf_ehdr->e_shoff); + break; + + default: + pr_debug("Unknown ELF class.\n"); + return -EINVAL; + } + return elf_is_ehdr_sane(ehdr, len) ? 0 : -ENOEXEC; }
@@ -192,6 +205,7 @@ static int elf_read_phdr(const char *buf, size_t len, { /* Override the const in proghdrs, we are the ones doing the loading. */ struct elf_phdr *phdr = (struct elf_phdr *) &elf_info->proghdrs[idx]; + const struct elfhdr *ehdr = elf_info->ehdr; const char *pbuf; struct elf_phdr *buf_phdr;
@@ -199,18 +213,31 @@ static int elf_read_phdr(const char *buf, size_t len, 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); + switch (ehdr->e_ident[EI_CLASS]) { + case ELFCLASS64: + phdr->p_offset = elf64_to_cpu(ehdr, buf_phdr->p_offset); + phdr->p_paddr = elf64_to_cpu(ehdr, buf_phdr->p_paddr); + phdr->p_vaddr = elf64_to_cpu(ehdr, buf_phdr->p_vaddr); + phdr->p_filesz = elf64_to_cpu(ehdr, buf_phdr->p_filesz); + phdr->p_memsz = elf64_to_cpu(ehdr, buf_phdr->p_memsz); + phdr->p_align = elf64_to_cpu(ehdr, buf_phdr->p_align); + break; + + case ELFCLASS32: + phdr->p_offset = elf32_to_cpu(ehdr, buf_phdr->p_offset); + phdr->p_paddr = elf32_to_cpu(ehdr, buf_phdr->p_paddr); + phdr->p_vaddr = elf32_to_cpu(ehdr, buf_phdr->p_vaddr); + phdr->p_filesz = elf32_to_cpu(ehdr, buf_phdr->p_filesz); + phdr->p_memsz = elf32_to_cpu(ehdr, buf_phdr->p_memsz); + phdr->p_align = elf32_to_cpu(ehdr, buf_phdr->p_align); + break; + + default: + pr_debug("Unknown ELF class.\n"); + return -EINVAL; + } return elf_is_phdr_sane(phdr, len) ? 0 : -ENOEXEC; }
--
2.23.0.rc1