Commit af65d648 authored by Roland McGrath's avatar Roland McGrath Committed by Ingo Molnar

x86 vDSO: consolidate vdso32

This makes x86_64's ia32 emulation support share the sources used in the
32-bit kernel for the 32-bit vDSO and much of its setup code.

The 32-bit vDSO mapping now behaves the same on x86_64 as on native 32-bit.
The abi.syscall32 sysctl on x86_64 now takes the same values that
vm.vdso_enabled takes on the 32-bit kernel.  That is, 1 means a randomized
vDSO location, 2 means the fixed old address.  The CONFIG_COMPAT_VDSO
option is now available to make this the default setting, the same meaning
it has for the 32-bit kernel.  (This does not affect the 64-bit vDSO.)

The argument vdso32=[012] can be used on both 32-bit and 64-bit kernels to
set this paramter at boot time.  The vdso=[012] argument still does this
same thing on the 32-bit kernel.
Signed-off-by: default avatarRoland McGrath <roland@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
parent 00f8b1bc
......@@ -1988,6 +1988,11 @@ and is between 256 and 4096 characters. It is defined in the file
vdso=1: enable VDSO (default)
vdso=0: disable VDSO mapping
vdso32= [X86-32,X86-64]
vdso32=2: enable compat VDSO (default with COMPAT_VDSO)
vdso32=1: enable 32-bit VDSO (default)
vdso32=0: disable 32-bit VDSO mapping
vector= [IA-64,SMP]
vector=percpu: enable percpu vector domain
......
......@@ -1191,9 +1191,9 @@ config HOTPLUG_CPU
config COMPAT_VDSO
bool "Compat VDSO support"
default y
depends on X86_32
depends on X86_32 || IA32_EMULATION
help
Map the VDSO to the predictable old-style address too.
Map the 32-bit VDSO to the predictable old-style address too.
---help---
Say N here if you are running a sufficiently recent glibc
version (2.3.3 or later), to remove the high-mapped
......
......@@ -3,7 +3,7 @@
#
obj-$(CONFIG_IA32_EMULATION) := ia32entry.o sys_ia32.o ia32_signal.o tls32.o \
ia32_binfmt.o fpu32.o ptrace32.o syscall32.o syscall32_syscall.o
ia32_binfmt.o fpu32.o ptrace32.o
sysv-$(CONFIG_SYSVIPC) := ipc32.o
obj-$(CONFIG_IA32_EMULATION) += $(sysv-y)
......
......@@ -26,7 +26,7 @@
#include <asm/i387.h>
#include <asm/uaccess.h>
#include <asm/ia32.h>
#include <asm/vsyscall32.h>
#include <asm/vdso.h>
#undef ELF_ARCH
#undef ELF_CLASS
......@@ -47,14 +47,13 @@
#define AT_SYSINFO 32
#define AT_SYSINFO_EHDR 33
int sysctl_vsyscall32 = 1;
extern int sysctl_vsyscall32;
#undef ARCH_DLINFO
#define ARCH_DLINFO do { \
if (sysctl_vsyscall32) { \
current->mm->context.vdso = (void *)VSYSCALL32_BASE; \
NEW_AUX_ENT(AT_SYSINFO, (u32)(u64)VSYSCALL32_VSYSCALL); \
NEW_AUX_ENT(AT_SYSINFO_EHDR, VSYSCALL32_BASE); \
NEW_AUX_ENT(AT_SYSINFO, (u32)VDSO_ENTRY); \
NEW_AUX_ENT(AT_SYSINFO_EHDR, (u32)VDSO_CURRENT_BASE); \
} \
} while(0)
......
......@@ -31,7 +31,7 @@
#include <asm/sigcontext32.h>
#include <asm/fpu32.h>
#include <asm/proto.h>
#include <asm/vsyscall32.h>
#include <asm/vdso.h>
#define DEBUG_SIG 0
......@@ -465,13 +465,16 @@ int ia32_setup_frame(int sig, struct k_sigaction *ka,
goto give_sigsegv;
}
/* Return stub is in 32bit vsyscall page */
if (current->binfmt->hasvdso)
restorer = VSYSCALL32_SIGRETURN;
else
restorer = (void *)&frame->retcode;
if (ka->sa.sa_flags & SA_RESTORER)
if (ka->sa.sa_flags & SA_RESTORER) {
restorer = ka->sa.sa_restorer;
} else {
/* Return stub is in 32bit vsyscall page */
if (current->binfmt->hasvdso)
restorer = VDSO32_SYMBOL(current->mm->context.vdso,
sigreturn);
else
restorer = (void *)&frame->retcode;
}
err |= __put_user(ptr_to_compat(restorer), &frame->pretcode);
/*
......@@ -519,7 +522,7 @@ int ia32_setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
{
struct rt_sigframe __user *frame;
struct exec_domain *ed = current_thread_info()->exec_domain;
void __user *restorer = VSYSCALL32_RTSIGRETURN;
void __user *restorer;
int err = 0;
/* __copy_to_user optimizes that into a single 8 byte store */
......@@ -564,6 +567,9 @@ int ia32_setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
if (ka->sa.sa_flags & SA_RESTORER)
restorer = ka->sa.sa_restorer;
else
restorer = VDSO32_SYMBOL(current->mm->context.vdso,
rt_sigreturn);
err |= __put_user(ptr_to_compat(restorer), &frame->pretcode);
/*
......
......@@ -15,7 +15,7 @@ vobjs-y := vdso-note.o vclock_gettime.o vgetcpu.o vvar.o
# files to link into kernel
obj-$(VDSO64-y) += vma.o vdso.o
obj-$(CONFIG_X86_32) += vdso32.o vdso32-setup.o
obj-$(VDSO32-y) += vdso32.o vdso32-setup.o
vobjs := $(foreach F,$(vobjs-y),$(obj)/$F)
......
......@@ -24,6 +24,7 @@
#include <asm/elf.h>
#include <asm/tlbflush.h>
#include <asm/vdso.h>
#include <asm/proto.h>
enum {
VDSO_DISABLED = 0,
......@@ -37,14 +38,24 @@ enum {
#define VDSO_DEFAULT VDSO_ENABLED
#endif
#ifdef CONFIG_X86_64
#define vdso_enabled sysctl_vsyscall32
#define arch_setup_additional_pages syscall32_setup_pages
#endif
/*
* This is the difference between the prelinked addresses in the vDSO images
* and the VDSO_HIGH_BASE address where CONFIG_COMPAT_VDSO places the vDSO
* in the user address space.
*/
#define VDSO_ADDR_ADJUST (VDSO_HIGH_BASE - (unsigned long)VDSO32_PRELINK)
/*
* Should the kernel map a VDSO page into processes and pass its
* address down to glibc upon exec()?
*/
unsigned int __read_mostly vdso_enabled = VDSO_DEFAULT;
EXPORT_SYMBOL_GPL(vdso_enabled);
static int __init vdso_setup(char *s)
{
vdso_enabled = simple_strtoul(s, NULL, 0);
......@@ -52,9 +63,18 @@ static int __init vdso_setup(char *s)
return 1;
}
__setup("vdso=", vdso_setup);
/*
* For consistency, the argument vdso32=[012] affects the 32-bit vDSO
* behavior on both 64-bit and 32-bit kernels.
* On 32-bit kernels, vdso=[012] means the same thing.
*/
__setup("vdso32=", vdso_setup);
extern asmlinkage void ia32_sysenter_target(void);
#ifdef CONFIG_X86_32
__setup_param("vdso=", vdso32_setup, vdso_setup, 0);
EXPORT_SYMBOL_GPL(vdso_enabled);
#endif
static __init void reloc_symtab(Elf32_Ehdr *ehdr,
unsigned offset, unsigned size)
......@@ -79,7 +99,7 @@ static __init void reloc_symtab(Elf32_Ehdr *ehdr,
case STT_FUNC:
case STT_SECTION:
case STT_FILE:
sym->st_value += VDSO_HIGH_BASE;
sym->st_value += VDSO_ADDR_ADJUST;
}
}
}
......@@ -105,7 +125,7 @@ static __init void reloc_dyn(Elf32_Ehdr *ehdr, unsigned offset)
case DT_VERNEED:
case DT_ADDRRNGLO ... DT_ADDRRNGHI:
/* definitely pointers needing relocation */
dyn->d_un.d_ptr += VDSO_HIGH_BASE;
dyn->d_un.d_ptr += VDSO_ADDR_ADJUST;
break;
case DT_ENCODING ... OLD_DT_LOOS-1:
......@@ -114,7 +134,7 @@ static __init void reloc_dyn(Elf32_Ehdr *ehdr, unsigned offset)
they're even */
if (dyn->d_tag >= DT_ENCODING &&
(dyn->d_tag & 1) == 0)
dyn->d_un.d_ptr += VDSO_HIGH_BASE;
dyn->d_un.d_ptr += VDSO_ADDR_ADJUST;
break;
case DT_VERDEFNUM:
......@@ -143,15 +163,15 @@ static __init void relocate_vdso(Elf32_Ehdr *ehdr)
int i;
BUG_ON(memcmp(ehdr->e_ident, ELFMAG, 4) != 0 ||
!elf_check_arch(ehdr) ||
!elf_check_arch_ia32(ehdr) ||
ehdr->e_type != ET_DYN);
ehdr->e_entry += VDSO_HIGH_BASE;
ehdr->e_entry += VDSO_ADDR_ADJUST;
/* rebase phdrs */
phdr = (void *)ehdr + ehdr->e_phoff;
for (i = 0; i < ehdr->e_phnum; i++) {
phdr[i].p_vaddr += VDSO_HIGH_BASE;
phdr[i].p_vaddr += VDSO_ADDR_ADJUST;
/* relocate dynamic stuff */
if (phdr[i].p_type == PT_DYNAMIC)
......@@ -164,7 +184,7 @@ static __init void relocate_vdso(Elf32_Ehdr *ehdr)
if (!(shdr[i].sh_flags & SHF_ALLOC))
continue;
shdr[i].sh_addr += VDSO_HIGH_BASE;
shdr[i].sh_addr += VDSO_ADDR_ADJUST;
if (shdr[i].sh_type == SHT_SYMTAB ||
shdr[i].sh_type == SHT_DYNSYM)
......@@ -173,6 +193,45 @@ static __init void relocate_vdso(Elf32_Ehdr *ehdr)
}
}
/*
* These symbols are defined by vdso32.S to mark the bounds
* of the ELF DSO images included therein.
*/
extern const char vdso32_default_start, vdso32_default_end;
extern const char vdso32_sysenter_start, vdso32_sysenter_end;
static struct page *vdso32_pages[1];
#ifdef CONFIG_X86_64
static int use_sysenter __read_mostly = -1;
#define vdso32_sysenter() (use_sysenter > 0)
/* May not be __init: called during resume */
void syscall32_cpu_init(void)
{
if (use_sysenter < 0)
use_sysenter = (boot_cpu_data.x86_vendor == X86_VENDOR_INTEL);
/* Load these always in case some future AMD CPU supports
SYSENTER from compat mode too. */
checking_wrmsrl(MSR_IA32_SYSENTER_CS, (u64)__KERNEL_CS);
checking_wrmsrl(MSR_IA32_SYSENTER_ESP, 0ULL);
checking_wrmsrl(MSR_IA32_SYSENTER_EIP, (u64)ia32_sysenter_target);
wrmsrl(MSR_CSTAR, ia32_cstar_target);
}
#define compat_uses_vma 1
static inline void map_compat_vdso(int map)
{
}
#else /* CONFIG_X86_32 */
#define vdso32_sysenter() (boot_cpu_has(X86_FEATURE_SEP))
void enable_sep_cpu(void)
{
int cpu = get_cpu();
......@@ -210,13 +269,7 @@ static int __init gate_vma_init(void)
return 0;
}
/*
* These symbols are defined by vsyscall.o to mark the bounds
* of the ELF DSO images included therein.
*/
extern const char vsyscall_int80_start, vsyscall_int80_end;
extern const char vsyscall_sysenter_start, vsyscall_sysenter_end;
static struct page *syscall_pages[1];
#define compat_uses_vma 0
static void map_compat_vdso(int map)
{
......@@ -227,31 +280,35 @@ static void map_compat_vdso(int map)
vdso_mapped = map;
__set_fixmap(FIX_VDSO, page_to_pfn(syscall_pages[0]) << PAGE_SHIFT,
__set_fixmap(FIX_VDSO, page_to_pfn(vdso32_pages[0]) << PAGE_SHIFT,
map ? PAGE_READONLY_EXEC : PAGE_NONE);
/* flush stray tlbs */
flush_tlb_all();
}
#endif /* CONFIG_X86_64 */
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);
vdso32_pages[0] = virt_to_page(syscall_page);
#ifdef CONFIG_X86_32
gate_vma_init();
printk("Compat vDSO mapped to %08lx.\n", __fix_to_virt(FIX_VDSO));
#endif
if (!boot_cpu_has(X86_FEATURE_SEP)) {
vsyscall = &vsyscall_int80_start;
vsyscall_len = &vsyscall_int80_end - &vsyscall_int80_start;
if (!vdso32_sysenter()) {
vsyscall = &vdso32_default_start;
vsyscall_len = &vdso32_default_end - &vdso32_default_start;
} else {
vsyscall = &vsyscall_sysenter_start;
vsyscall_len = &vsyscall_sysenter_end - &vsyscall_sysenter_start;
vsyscall = &vdso32_sysenter_start;
vsyscall_len = &vdso32_sysenter_end - &vdso32_sysenter_start;
}
memcpy(syscall_page, vsyscall, vsyscall_len);
......@@ -284,7 +341,9 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int exstack)
ret = addr;
goto up_fail;
}
}
if (compat_uses_vma || !compat) {
/*
* MAYWRITE to allow gdb to COW and set breakpoints
*
......@@ -298,7 +357,7 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int exstack)
VM_READ|VM_EXEC|
VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC|
VM_ALWAYSDUMP,
syscall_pages);
vdso32_pages);
if (ret)
goto up_fail;
......@@ -314,6 +373,12 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int exstack)
return ret;
}
#ifdef CONFIG_X86_64
__initcall(sysenter_setup);
#else /* CONFIG_X86_32 */
const char *arch_vma_name(struct vm_area_struct *vma)
{
if (vma->vm_mm && vma->vm_start == (long)vma->vm_mm->context.vdso)
......@@ -342,3 +407,5 @@ int in_gate_area_no_task(unsigned long addr)
{
return 0;
}
#endif /* CONFIG_X86_64 */
......@@ -2,14 +2,18 @@
__INITDATA
.globl vsyscall_int80_start, vsyscall_int80_end
vsyscall_int80_start:
.globl vdso32_default_start, vdso32_default_end
vdso32_default_start:
#ifdef CONFIG_X86_32
.incbin "arch/x86/vdso/vdso32-int80.so"
vsyscall_int80_end:
#else
.incbin "arch/x86/vdso/vdso32-syscall.so"
#endif
vdso32_default_end:
.globl vsyscall_sysenter_start, vsyscall_sysenter_end
vsyscall_sysenter_start:
.globl vdso32_sysenter_start, vdso32_sysenter_end
vdso32_sysenter_start:
.incbin "arch/x86/vdso/vdso32-sysenter.so"
vsyscall_sysenter_end:
vdso32_sysenter_end:
__FINIT
......@@ -62,8 +62,8 @@ static void xen_idle(void)
*/
static void fiddle_vdso(void)
{
extern char vsyscall_int80_start;
u32 *mask = VDSO32_SYMBOL(&vsyscall_int80_start, NOTE_MASK);
extern const char vdso32_default_start;
u32 *mask = VDSO32_SYMBOL(&vdso32_default_start, NOTE_MASK);
*mask |= 1 << VDSO_NOTE_NONEGSEG_BIT;
}
......
......@@ -74,17 +74,19 @@ typedef struct user_fxsr_struct elf_fpxregset_t;
#ifdef __KERNEL__
/*
* This is used to ensure we don't load something for the wrong architecture.
*/
#define elf_check_arch_ia32(x) \
(((x)->e_machine == EM_386) || ((x)->e_machine == EM_486))
#ifdef CONFIG_X86_32
#include <asm/processor.h>
#include <asm/system.h> /* for savesegment */
#include <asm/desc.h>
#include <asm/vdso.h>
/*
* This is used to ensure we don't load something for the wrong architecture.
*/
#define elf_check_arch(x) \
(((x)->e_machine == EM_386) || ((x)->e_machine == EM_486))
#define elf_check_arch(x) elf_check_arch_ia32(x)
/* SVR4/i386 ABI (pages 3-31, 3-32) says that when the program starts %edx
contains a pointer to a function which might be registered using `atexit'.
......@@ -247,10 +249,6 @@ extern int dump_task_extended_fpu (struct task_struct *,
#define ELF_CORE_XFPREG_TYPE NT_PRXFPREG
#define VDSO_HIGH_BASE (__fix_to_virt(FIX_VDSO))
#define VDSO_CURRENT_BASE ((unsigned long)current->mm->context.vdso)
#define VDSO_ENTRY \
((unsigned long) VDSO32_SYMBOL(VDSO_CURRENT_BASE, vsyscall))
/* update AT_VECTOR_SIZE_ARCH if the number of NEW_AUX_ENT entries changes */
......@@ -262,6 +260,8 @@ do if (vdso_enabled) { \
#else /* CONFIG_X86_32 */
#define VDSO_HIGH_BASE 0xffffe000U /* CONFIG_COMPAT_VDSO address */
/* 1GB for 64bit, 8MB for 32bit */
#define STACK_RND_MASK (test_thread_flag(TIF_IA32) ? 0x7ff : 0x3fffff)
......@@ -272,6 +272,11 @@ do if (vdso_enabled) { \
#endif /* !CONFIG_X86_32 */
#define VDSO_CURRENT_BASE ((unsigned long)current->mm->context.vdso)
#define VDSO_ENTRY \
((unsigned long) VDSO32_SYMBOL(VDSO_CURRENT_BASE, vsyscall))
struct linux_binprm;
#define ARCH_HAS_SETUP_ADDITIONAL_PAGES 1
......
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