[PATCH] i386: Relocate VDSO ELF headers to match mapped location with COMPAT_VDSO (d4f7a2c1) · Commits · 戴 / test

arch/i386/kernel/entry.S

+0 −4

Original line number	Diff line number	Diff line
		@@ -305,16 +305,12 @@ sysenter_past_esp:
		pushl $(__USER_CS)
		CFI_ADJUST_CFA_OFFSET 4
		/CFI_REL_OFFSET cs, 0/
		#ifndef CONFIG_COMPAT_VDSO
		/*
		* Push current_thread_info()->sysenter_return to the stack.
		* A tiny bit of offset fixup is necessary - 4*4 means the 4 words
		* pushed above; +8 corresponds to copy_thread's esp0 setting.
		*/
		pushl (TI_sysenter_return-THREAD_SIZE+8+4*4)(%esp)
		#else
		pushl $SYSENTER_RETURN
		#endif
		CFI_ADJUST_CFA_OFFSET 4
		CFI_REL_OFFSET eip, 0

arch/i386/kernel/sysenter.c

+149 −9

Original line number	Diff line number	Diff line
		@@ -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 */

arch/i386/mm/pgtable.c

+0 −6

Original line number	Diff line number	Diff line
		@@ -144,10 +144,8 @@ void set_pmd_pfn(unsigned long vaddr, unsigned long pfn, pgprot_t flags)
		}

		static int fixmaps;
		#ifndef CONFIG_COMPAT_VDSO
		unsigned long __FIXADDR_TOP = 0xfffff000;
		EXPORT_SYMBOL(__FIXADDR_TOP);
		#endif

		void __set_fixmap (enum fixed_addresses idx, unsigned long phys, pgprot_t flags)
		{
		@@ -173,12 +171,8 @@ void reserve_top_address(unsigned long reserve)
		BUG_ON(fixmaps > 0);
		printk(KERN_INFO "Reserving virtual address space above 0x%08x\n",
		(int)-reserve);
		#ifdef CONFIG_COMPAT_VDSO
		BUG_ON(reserve != 0);
		#else
		__FIXADDR_TOP = -reserve - PAGE_SIZE;
		__VMALLOC_RESERVE += reserve;
		#endif
		}

		pte_t pte_alloc_one_kernel(struct mm_struct mm, unsigned long address)

include/asm-i386/elf.h

+10 −18

Original line number	Diff line number	Diff line
		@@ -133,39 +133,31 @@ extern int dump_task_extended_fpu (struct task_struct *, struct user_fxsr_struct
		#define ELF_CORE_COPY_XFPREGS(tsk, elf_xfpregs) dump_task_extended_fpu(tsk, elf_xfpregs)

		#define VDSO_HIGH_BASE (__fix_to_virt(FIX_VDSO))
		#define VDSO_BASE ((unsigned long)current->mm->context.vdso)

		#ifdef CONFIG_COMPAT_VDSO
		# define VDSO_COMPAT_BASE VDSO_HIGH_BASE
		# define VDSO_PRELINK VDSO_HIGH_BASE
		#else
		# define VDSO_COMPAT_BASE VDSO_BASE
		#define VDSO_CURRENT_BASE ((unsigned long)current->mm->context.vdso)
		#define VDSO_PRELINK 0
		#endif

		#define VDSO_SYM(x) \
		(VDSO_COMPAT_BASE + (unsigned long)(x) - VDSO_PRELINK)
		(VDSO_CURRENT_BASE + (unsigned long)(x) - VDSO_PRELINK)

		#define VDSO_HIGH_EHDR ((const struct elfhdr *) VDSO_HIGH_BASE)
		#define VDSO_EHDR ((const struct elfhdr *) VDSO_COMPAT_BASE)
		#define VDSO_EHDR ((const struct elfhdr *) VDSO_CURRENT_BASE)

		extern void __kernel_vsyscall;

		#define VDSO_ENTRY VDSO_SYM(&__kernel_vsyscall)

		#ifndef CONFIG_COMPAT_VDSO
		#define ARCH_HAS_SETUP_ADDITIONAL_PAGES
		struct linux_binprm;

		#define ARCH_HAS_SETUP_ADDITIONAL_PAGES
		extern int arch_setup_additional_pages(struct linux_binprm *bprm,
		int executable_stack);
		#endif

		extern unsigned int vdso_enabled;

		#define ARCH_DLINFO \
		do if (vdso_enabled) { \
		NEW_AUX_ENT(AT_SYSINFO, VDSO_ENTRY); \
		NEW_AUX_ENT(AT_SYSINFO_EHDR, VDSO_COMPAT_BASE); \
		NEW_AUX_ENT(AT_SYSINFO_EHDR, VDSO_CURRENT_BASE); \
		} while (0)

		#endif

include/asm-i386/fixmap.h

+2 −6

Original line number	Diff line number	Diff line
		@@ -19,13 +19,9 @@
		* Leave one empty page between vmalloc'ed areas and
		* the start of the fixmap.
		*/
		#ifndef CONFIG_COMPAT_VDSO
		extern unsigned long __FIXADDR_TOP;
		#else
		#define __FIXADDR_TOP 0xfffff000
		#define FIXADDR_USER_START __fix_to_virt(FIX_VDSO)
		#define FIXADDR_USER_END __fix_to_virt(FIX_VDSO - 1)
		#endif

		#ifndef __ASSEMBLY__
		#include <linux/kernel.h>

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