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kernel-fxtec-pro1x/arch/x86_64/ia32/ia32_binfmt.c
Andi Kleen 2aae950b21 x86_64: Add vDSO for x86-64 with gettimeofday/clock_gettime/getcpu 
This implements new vDSO for x86-64.  The concept is similar
to the existing vDSOs on i386 and PPC.  x86-64 has had static
vsyscalls before,  but these are not flexible enough anymore.

A vDSO is a ELF shared library supplied by the kernel that is mapped into
user address space.  The vDSO mapping is randomized for each process
for security reasons.

Doing this was needed for clock_gettime, because clock_gettime
always needs a syscall fallback and having one at a fixed
address would have made buffer overflow exploits too easy to write.

The vdso can be disabled with vdso=0

It currently includes a new gettimeofday implemention and optimized
clock_gettime(). The gettimeofday implementation is slightly faster
than the one in the old vsyscall.  clock_gettime is significantly faster
than the syscall for CLOCK_MONOTONIC and CLOCK_REALTIME.

The new calls are generally faster than the old vsyscall.

Advantages over the old x86-64 vsyscalls:
- Extensible
- Randomized
- Cleaner
- Easier to virtualize (the old static address range previously causes
overhead e.g. for Xen because it has to create special page tables for it)

Weak points:
- glibc support still to be written

The VM interface is partly based on Ingo Molnar's i386 version.

Includes compile fix from Joachim Deguara

Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-21 18:37:08 -07:00

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/*
* Written 2000,2002 by Andi Kleen.
*
* Loosely based on the sparc64 and IA64 32bit emulation loaders.
* This tricks binfmt_elf.c into loading 32bit binaries using lots
* of ugly preprocessor tricks. Talk about very very poor man's inheritance.
*/
#define __ASM_X86_64_ELF_H 1
#undef ELF_CLASS
#define ELF_CLASS ELFCLASS32
#include <linux/types.h>
#include <linux/stddef.h>
#include <linux/rwsem.h>
#include <linux/sched.h>
#include <linux/compat.h>
#include <linux/string.h>
#include <linux/binfmts.h>
#include <linux/mm.h>
#include <linux/security.h>
#include <asm/segment.h>
#include <asm/ptrace.h>
#include <asm/processor.h>
#include <asm/user32.h>
#include <asm/sigcontext32.h>
#include <asm/fpu32.h>
#include <asm/i387.h>
#include <asm/uaccess.h>
#include <asm/ia32.h>
#include <asm/vsyscall32.h>
#define ELF_NAME "elf/i386"
#define AT_SYSINFO 32
#define AT_SYSINFO_EHDR 33
int sysctl_vsyscall32 = 1;
#undef ARCH_DLINFO
#define ARCH_DLINFO do { \
if (sysctl_vsyscall32) { \
NEW_AUX_ENT(AT_SYSINFO, (u32)(u64)VSYSCALL32_VSYSCALL); \
NEW_AUX_ENT(AT_SYSINFO_EHDR, VSYSCALL32_BASE); \
} \
} while(0)
struct file;
struct elf_phdr;
#define IA32_EMULATOR 1
#define ELF_ET_DYN_BASE (TASK_UNMAPPED_BASE + 0x1000000)
#undef ELF_ARCH
#define ELF_ARCH EM_386
#define ELF_DATA ELFDATA2LSB
#define USE_ELF_CORE_DUMP 1
/* Override elfcore.h */
#define _LINUX_ELFCORE_H 1
typedef unsigned int elf_greg_t;
#define ELF_NGREG (sizeof (struct user_regs_struct32) / sizeof(elf_greg_t))
typedef elf_greg_t elf_gregset_t[ELF_NGREG];
struct elf_siginfo
{
int si_signo; /* signal number */
int si_code; /* extra code */
int si_errno; /* errno */
};
#define jiffies_to_timeval(a,b) do { (b)->tv_usec = 0; (b)->tv_sec = (a)/HZ; }while(0)
struct elf_prstatus
{
struct elf_siginfo pr_info; /* Info associated with signal */
short pr_cursig; /* Current signal */
unsigned int pr_sigpend; /* Set of pending signals */
unsigned int pr_sighold; /* Set of held signals */
pid_t pr_pid;
pid_t pr_ppid;
pid_t pr_pgrp;
pid_t pr_sid;
struct compat_timeval pr_utime; /* User time */
struct compat_timeval pr_stime; /* System time */
struct compat_timeval pr_cutime; /* Cumulative user time */
struct compat_timeval pr_cstime; /* Cumulative system time */
elf_gregset_t pr_reg; /* GP registers */
int pr_fpvalid; /* True if math co-processor being used. */
};
#define ELF_PRARGSZ (80) /* Number of chars for args */
struct elf_prpsinfo
{
char pr_state; /* numeric process state */
char pr_sname; /* char for pr_state */
char pr_zomb; /* zombie */
char pr_nice; /* nice val */
unsigned int pr_flag; /* flags */
__u16 pr_uid;
__u16 pr_gid;
pid_t pr_pid, pr_ppid, pr_pgrp, pr_sid;
/* Lots missing */
char pr_fname[16]; /* filename of executable */
char pr_psargs[ELF_PRARGSZ]; /* initial part of arg list */
};
#define __STR(x) #x
#define STR(x) __STR(x)
#define _GET_SEG(x) \
({ __u32 seg; asm("movl %%" STR(x) ",%0" : "=r"(seg)); seg; })
/* Assumes current==process to be dumped */
#define ELF_CORE_COPY_REGS(pr_reg, regs) \
pr_reg[0] = regs->rbx; \
pr_reg[1] = regs->rcx; \
pr_reg[2] = regs->rdx; \
pr_reg[3] = regs->rsi; \
pr_reg[4] = regs->rdi; \
pr_reg[5] = regs->rbp; \
pr_reg[6] = regs->rax; \
pr_reg[7] = _GET_SEG(ds); \
pr_reg[8] = _GET_SEG(es); \
pr_reg[9] = _GET_SEG(fs); \
pr_reg[10] = _GET_SEG(gs); \
pr_reg[11] = regs->orig_rax; \
pr_reg[12] = regs->rip; \
pr_reg[13] = regs->cs; \
pr_reg[14] = regs->eflags; \
pr_reg[15] = regs->rsp; \
pr_reg[16] = regs->ss;
#define user user32
#undef elf_read_implies_exec
#define elf_read_implies_exec(ex, executable_stack) (executable_stack != EXSTACK_DISABLE_X)
//#include <asm/ia32.h>
#include <linux/elf.h>
typedef struct user_i387_ia32_struct elf_fpregset_t;
typedef struct user32_fxsr_struct elf_fpxregset_t;
static inline void elf_core_copy_regs(elf_gregset_t *elfregs, struct pt_regs *regs)
{
ELF_CORE_COPY_REGS((*elfregs), regs)
}
static inline int elf_core_copy_task_regs(struct task_struct *t, elf_gregset_t* elfregs)
{
struct pt_regs *pp = task_pt_regs(t);
ELF_CORE_COPY_REGS((*elfregs), pp);
/* fix wrong segments */
(*elfregs)[7] = t->thread.ds;
(*elfregs)[9] = t->thread.fsindex;
(*elfregs)[10] = t->thread.gsindex;
(*elfregs)[8] = t->thread.es;
return 1;
}
static inline int
elf_core_copy_task_fpregs(struct task_struct *tsk, struct pt_regs *regs, elf_fpregset_t *fpu)
{
struct _fpstate_ia32 *fpstate = (void*)fpu;
mm_segment_t oldfs = get_fs();
if (!tsk_used_math(tsk))
return 0;
if (!regs)
regs = task_pt_regs(tsk);
if (tsk == current)
unlazy_fpu(tsk);
set_fs(KERNEL_DS);
save_i387_ia32(tsk, fpstate, regs, 1);
/* Correct for i386 bug. It puts the fop into the upper 16bits of
the tag word (like FXSAVE), not into the fcs*/
fpstate->cssel |= fpstate->tag & 0xffff0000;
set_fs(oldfs);
return 1;
}
#define ELF_CORE_COPY_XFPREGS 1
static inline int
elf_core_copy_task_xfpregs(struct task_struct *t, elf_fpxregset_t *xfpu)
{
struct pt_regs *regs = task_pt_regs(t);
if (!tsk_used_math(t))
return 0;
if (t == current)
unlazy_fpu(t);
memcpy(xfpu, &t->thread.i387.fxsave, sizeof(elf_fpxregset_t));
xfpu->fcs = regs->cs;
xfpu->fos = t->thread.ds; /* right? */
return 1;
}
#undef elf_check_arch
#define elf_check_arch(x) \
((x)->e_machine == EM_386)
extern int force_personality32;
#define ELF_EXEC_PAGESIZE PAGE_SIZE
#define ELF_HWCAP (boot_cpu_data.x86_capability[0])
#define ELF_PLATFORM ("i686")
#define SET_PERSONALITY(ex, ibcs2) \
do { \
unsigned long new_flags = 0; \
if ((ex).e_ident[EI_CLASS] == ELFCLASS32) \
new_flags = _TIF_IA32; \
if ((current_thread_info()->flags & _TIF_IA32) \
!= new_flags) \
set_thread_flag(TIF_ABI_PENDING); \
else \
clear_thread_flag(TIF_ABI_PENDING); \
/* XXX This overwrites the user set personality */ \
current->personality |= force_personality32; \
} while (0)
/* Override some function names */
#define elf_format elf32_format
#define init_elf_binfmt init_elf32_binfmt
#define exit_elf_binfmt exit_elf32_binfmt
#define load_elf_binary load_elf32_binary
#define ELF_PLAT_INIT(r, load_addr) elf32_init(r)
#undef start_thread
#define start_thread(regs,new_rip,new_rsp) do { \
asm volatile("movl %0,%%fs" :: "r" (0)); \
asm volatile("movl %0,%%es; movl %0,%%ds": :"r" (__USER32_DS)); \
load_gs_index(0); \
(regs)->rip = (new_rip); \
(regs)->rsp = (new_rsp); \
(regs)->eflags = 0x200; \
(regs)->cs = __USER32_CS; \
(regs)->ss = __USER32_DS; \
set_fs(USER_DS); \
} while(0)
#include <linux/module.h>
MODULE_DESCRIPTION("Binary format loader for compatibility with IA32 ELF binaries.");
MODULE_AUTHOR("Eric Youngdale, Andi Kleen");
#undef MODULE_DESCRIPTION
#undef MODULE_AUTHOR
static void elf32_init(struct pt_regs *);
#define ARCH_HAS_SETUP_ADDITIONAL_PAGES 1
#define arch_setup_additional_pages syscall32_setup_pages
extern int syscall32_setup_pages(struct linux_binprm *, int exstack);
#include "../../../fs/binfmt_elf.c"
static void elf32_init(struct pt_regs *regs)
{
struct task_struct *me = current;
regs->rdi = 0;
regs->rsi = 0;
regs->rdx = 0;
regs->rcx = 0;
regs->rax = 0;
regs->rbx = 0;
regs->rbp = 0;
regs->r8 = regs->r9 = regs->r10 = regs->r11 = regs->r12 =
regs->r13 = regs->r14 = regs->r15 = 0;
me->thread.fs = 0;
me->thread.gs = 0;
me->thread.fsindex = 0;
me->thread.gsindex = 0;
me->thread.ds = __USER_DS;
me->thread.es = __USER_DS;
}
#ifdef CONFIG_SYSCTL
/* Register vsyscall32 into the ABI table */
#include <linux/sysctl.h>
static ctl_table abi_table2[] = {
{
.ctl_name = 99,
.procname = "vsyscall32",
.data = &sysctl_vsyscall32,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec
},
{}
};
static ctl_table abi_root_table2[] = {
{
.ctl_name = CTL_ABI,
.procname = "abi",
.mode = 0555,
.child = abi_table2
},
{}
};
static __init int ia32_binfmt_init(void)
{
register_sysctl_table(abi_root_table2);
return 0;
}
__initcall(ia32_binfmt_init);
#endif
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