xiaomi-sm8450/android_kernel_xiaomi_sm8450
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

x86 vDSO: consolidate vdso32

Browse Source 
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: Roland McGrath <roland@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This commit is contained in:
Roland McGrath
2008-01-30 13:30:43 +01:00
committed by Ingo Molnar
parent 00f8b1bc0e
commit af65d64845
10 changed files with 146 additions and 60 deletions
Download Patch File Download Diff File Expand all files Collapse all files

119
arch/x86/vdso/vdso32-setup.c
View File

@@ -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 */