diff options
Diffstat (limited to 'arch/i386/kernel/sysenter.c')
| -rw-r--r-- | arch/i386/kernel/sysenter.c | 158 |
1 files changed, 149 insertions, 9 deletions
diff --git a/arch/i386/kernel/sysenter.c b/arch/i386/kernel/sysenter.c index 13ca54a85a1c..e5a958379ac9 100644 --- a/arch/i386/kernel/sysenter.c +++ b/arch/i386/kernel/sysenter.c @@ -22,6 +22,7 @@ #include <asm/msr.h> #include <asm/pgtable.h> #include <asm/unistd.h> +#include <asm/elf.h> /* * Should the kernel map a VDSO page into processes and pass its @@ -46,6 +47,129 @@ __setup("vdso=", vdso_setup); extern asmlinkage void sysenter_entry(void); +#ifdef CONFIG_COMPAT_VDSO +static __init void reloc_symtab(Elf32_Ehdr *ehdr, + unsigned offset, unsigned size) +{ + Elf32_Sym *sym = (void *)ehdr + offset; + unsigned nsym = size / sizeof(*sym); + unsigned i; + + for(i = 0; i < nsym; i++, sym++) { + if (sym->st_shndx == SHN_UNDEF || + sym->st_shndx == SHN_ABS) + continue; /* skip */ + + if (sym->st_shndx > SHN_LORESERVE) { + printk(KERN_INFO "VDSO: unexpected st_shndx %x\n", + sym->st_shndx); + continue; + } + + switch(ELF_ST_TYPE(sym->st_info)) { + case STT_OBJECT: + case STT_FUNC: + case STT_SECTION: + case STT_FILE: + sym->st_value += VDSO_HIGH_BASE; + } + } +} + +static __init void reloc_dyn(Elf32_Ehdr *ehdr, unsigned offset) +{ + Elf32_Dyn *dyn = (void *)ehdr + offset; + + for(; dyn->d_tag != DT_NULL; dyn++) + switch(dyn->d_tag) { + case DT_PLTGOT: + case DT_HASH: + case DT_STRTAB: + case DT_SYMTAB: + case DT_RELA: + case DT_INIT: + case DT_FINI: + case DT_REL: + case DT_DEBUG: + case DT_JMPREL: + case DT_VERSYM: + case DT_VERDEF: + case DT_VERNEED: + case DT_ADDRRNGLO ... DT_ADDRRNGHI: + /* definitely pointers needing relocation */ + dyn->d_un.d_ptr += VDSO_HIGH_BASE; + break; + + case DT_ENCODING ... OLD_DT_LOOS-1: + case DT_LOOS ... DT_HIOS-1: + /* Tags above DT_ENCODING are pointers if + they're even */ + if (dyn->d_tag >= DT_ENCODING && + (dyn->d_tag & 1) == 0) + dyn->d_un.d_ptr += VDSO_HIGH_BASE; + break; + + case DT_VERDEFNUM: + case DT_VERNEEDNUM: + case DT_FLAGS_1: + case DT_RELACOUNT: + case DT_RELCOUNT: + case DT_VALRNGLO ... DT_VALRNGHI: + /* definitely not pointers */ + break; + + case OLD_DT_LOOS ... DT_LOOS-1: + case DT_HIOS ... DT_VALRNGLO-1: + default: + if (dyn->d_tag > DT_ENCODING) + printk(KERN_INFO "VDSO: unexpected DT_tag %x\n", + dyn->d_tag); + break; + } +} + +static __init void relocate_vdso(Elf32_Ehdr *ehdr) +{ + Elf32_Phdr *phdr; + Elf32_Shdr *shdr; + int i; + + BUG_ON(memcmp(ehdr->e_ident, ELFMAG, 4) != 0 || + !elf_check_arch(ehdr) || + ehdr->e_type != ET_DYN); + + ehdr->e_entry += VDSO_HIGH_BASE; + + /* rebase phdrs */ + phdr = (void *)ehdr + ehdr->e_phoff; + for (i = 0; i < ehdr->e_phnum; i++) { + phdr[i].p_vaddr += VDSO_HIGH_BASE; + + /* relocate dynamic stuff */ + if (phdr[i].p_type == PT_DYNAMIC) + reloc_dyn(ehdr, phdr[i].p_offset); + } + + /* rebase sections */ + shdr = (void *)ehdr + ehdr->e_shoff; + for(i = 0; i < ehdr->e_shnum; i++) { + if (!(shdr[i].sh_flags & SHF_ALLOC)) + continue; + + shdr[i].sh_addr += VDSO_HIGH_BASE; + + if (shdr[i].sh_type == SHT_SYMTAB || + shdr[i].sh_type == SHT_DYNSYM) + reloc_symtab(ehdr, shdr[i].sh_offset, + shdr[i].sh_size); + } +} +#else +static inline void relocate_vdso(Elf32_Ehdr *ehdr) +{ +} +#endif /* COMPAT_VDSO */ + void enable_sep_cpu(void) { int cpu = get_cpu(); @@ -75,6 +199,9 @@ static struct page *syscall_pages[1]; int __init sysenter_setup(void) { void *syscall_page = (void *)get_zeroed_page(GFP_ATOMIC); + const void *vsyscall; + size_t vsyscall_len; + syscall_pages[0] = virt_to_page(syscall_page); #ifdef CONFIG_COMPAT_VDSO @@ -83,23 +210,23 @@ int __init sysenter_setup(void) #endif if (!boot_cpu_has(X86_FEATURE_SEP)) { - memcpy(syscall_page, - &vsyscall_int80_start, - &vsyscall_int80_end - &vsyscall_int80_start); - return 0; + vsyscall = &vsyscall_int80_start; + vsyscall_len = &vsyscall_int80_end - &vsyscall_int80_start; + } else { + vsyscall = &vsyscall_sysenter_start; + vsyscall_len = &vsyscall_sysenter_end - &vsyscall_sysenter_start; } - memcpy(syscall_page, - &vsyscall_sysenter_start, - &vsyscall_sysenter_end - &vsyscall_sysenter_start); + memcpy(syscall_page, vsyscall, vsyscall_len); + relocate_vdso(syscall_page); return 0; } -#ifndef CONFIG_COMPAT_VDSO /* Defined in vsyscall-sysenter.S */ extern void SYSENTER_RETURN; +#ifdef __HAVE_ARCH_GATE_AREA /* Setup a VMA at program startup for the vsyscall page */ int arch_setup_additional_pages(struct linux_binprm *bprm, int exstack) { @@ -159,4 +286,17 @@ int in_gate_area_no_task(unsigned long addr) { return 0; } -#endif +#else /* !__HAVE_ARCH_GATE_AREA */ +int arch_setup_additional_pages(struct linux_binprm *bprm, int exstack) +{ + /* + * If not creating userspace VMA, simply set vdso to point to + * fixmap page. + */ + current->mm->context.vdso = (void *)VDSO_HIGH_BASE; + current_thread_info()->sysenter_return = + (void *)VDSO_SYM(&SYSENTER_RETURN); + + return 0; +} +#endif /* __HAVE_ARCH_GATE_AREA */ |