ec0063b40a
It's possible to get an invalid page fault in kernel mode when we try to write out segments from vsyscall32 when dumping core for a 32bit process if the vsyscall32 DSO is not mapped in its address space (which can happen if, for example, ulimit -v 100 is run). Signed-off-by: Suleiman Souhlal <suleiman@google.com> Signed-off-by: Andi Kleen <ak@suse.de> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
419 lines
12 KiB
C
419 lines
12 KiB
C
/*
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* Written 2000,2002 by Andi Kleen.
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*
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* Loosely based on the sparc64 and IA64 32bit emulation loaders.
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* This tricks binfmt_elf.c into loading 32bit binaries using lots
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* of ugly preprocessor tricks. Talk about very very poor man's inheritance.
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*/
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#include <linux/types.h>
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#include <linux/config.h>
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#include <linux/stddef.h>
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#include <linux/rwsem.h>
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#include <linux/sched.h>
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#include <linux/compat.h>
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#include <linux/string.h>
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#include <linux/binfmts.h>
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#include <linux/mm.h>
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#include <linux/security.h>
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#include <asm/segment.h>
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#include <asm/ptrace.h>
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#include <asm/processor.h>
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#include <asm/user32.h>
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#include <asm/sigcontext32.h>
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#include <asm/fpu32.h>
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#include <asm/i387.h>
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#include <asm/uaccess.h>
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#include <asm/ia32.h>
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#include <asm/vsyscall32.h>
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#define ELF_NAME "elf/i386"
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#define AT_SYSINFO 32
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#define AT_SYSINFO_EHDR 33
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int sysctl_vsyscall32 = 1;
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#define ARCH_DLINFO do { \
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if (sysctl_vsyscall32) { \
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NEW_AUX_ENT(AT_SYSINFO, (u32)(u64)VSYSCALL32_VSYSCALL); \
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NEW_AUX_ENT(AT_SYSINFO_EHDR, VSYSCALL32_BASE); \
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} \
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} while(0)
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struct file;
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struct elf_phdr;
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#define IA32_EMULATOR 1
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#define ELF_ET_DYN_BASE (TASK_UNMAPPED_BASE + 0x1000000)
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#undef ELF_ARCH
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#define ELF_ARCH EM_386
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#undef ELF_CLASS
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#define ELF_CLASS ELFCLASS32
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#define ELF_DATA ELFDATA2LSB
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#define USE_ELF_CORE_DUMP 1
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/* Override elfcore.h */
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#define _LINUX_ELFCORE_H 1
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typedef unsigned int elf_greg_t;
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#define ELF_NGREG (sizeof (struct user_regs_struct32) / sizeof(elf_greg_t))
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typedef elf_greg_t elf_gregset_t[ELF_NGREG];
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/*
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* These macros parameterize elf_core_dump in fs/binfmt_elf.c to write out
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* extra segments containing the vsyscall DSO contents. Dumping its
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* contents makes post-mortem fully interpretable later without matching up
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* the same kernel and hardware config to see what PC values meant.
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* Dumping its extra ELF program headers includes all the other information
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* a debugger needs to easily find how the vsyscall DSO was being used.
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*/
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#define ELF_CORE_EXTRA_PHDRS (find_vma(current->mm, VSYSCALL32_BASE) ? \
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(VSYSCALL32_EHDR->e_phnum) : 0)
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#define ELF_CORE_WRITE_EXTRA_PHDRS \
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do { \
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if (find_vma(current->mm, VSYSCALL32_BASE)) { \
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const struct elf32_phdr *const vsyscall_phdrs = \
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(const struct elf32_phdr *) (VSYSCALL32_BASE \
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+ VSYSCALL32_EHDR->e_phoff);\
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int i; \
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Elf32_Off ofs = 0; \
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for (i = 0; i < VSYSCALL32_EHDR->e_phnum; ++i) { \
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struct elf32_phdr phdr = vsyscall_phdrs[i]; \
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if (phdr.p_type == PT_LOAD) { \
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BUG_ON(ofs != 0); \
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ofs = phdr.p_offset = offset; \
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phdr.p_memsz = PAGE_ALIGN(phdr.p_memsz); \
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phdr.p_filesz = phdr.p_memsz; \
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offset += phdr.p_filesz; \
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} \
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else \
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phdr.p_offset += ofs; \
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phdr.p_paddr = 0; /* match other core phdrs */ \
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DUMP_WRITE(&phdr, sizeof(phdr)); \
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} \
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} \
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} while (0)
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#define ELF_CORE_WRITE_EXTRA_DATA \
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do { \
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if (find_vma(current->mm, VSYSCALL32_BASE)) { \
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const struct elf32_phdr *const vsyscall_phdrs = \
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(const struct elf32_phdr *) (VSYSCALL32_BASE \
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+ VSYSCALL32_EHDR->e_phoff); \
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int i; \
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for (i = 0; i < VSYSCALL32_EHDR->e_phnum; ++i) { \
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if (vsyscall_phdrs[i].p_type == PT_LOAD) \
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DUMP_WRITE((void *) (u64) vsyscall_phdrs[i].p_vaddr,\
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PAGE_ALIGN(vsyscall_phdrs[i].p_memsz)); \
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} \
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} \
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} while (0)
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struct elf_siginfo
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{
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int si_signo; /* signal number */
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int si_code; /* extra code */
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int si_errno; /* errno */
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};
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#define jiffies_to_timeval(a,b) do { (b)->tv_usec = 0; (b)->tv_sec = (a)/HZ; }while(0)
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struct elf_prstatus
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{
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struct elf_siginfo pr_info; /* Info associated with signal */
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short pr_cursig; /* Current signal */
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unsigned int pr_sigpend; /* Set of pending signals */
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unsigned int pr_sighold; /* Set of held signals */
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pid_t pr_pid;
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pid_t pr_ppid;
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pid_t pr_pgrp;
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pid_t pr_sid;
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struct compat_timeval pr_utime; /* User time */
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struct compat_timeval pr_stime; /* System time */
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struct compat_timeval pr_cutime; /* Cumulative user time */
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struct compat_timeval pr_cstime; /* Cumulative system time */
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elf_gregset_t pr_reg; /* GP registers */
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int pr_fpvalid; /* True if math co-processor being used. */
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};
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#define ELF_PRARGSZ (80) /* Number of chars for args */
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struct elf_prpsinfo
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{
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char pr_state; /* numeric process state */
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char pr_sname; /* char for pr_state */
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char pr_zomb; /* zombie */
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char pr_nice; /* nice val */
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unsigned int pr_flag; /* flags */
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__u16 pr_uid;
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__u16 pr_gid;
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pid_t pr_pid, pr_ppid, pr_pgrp, pr_sid;
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/* Lots missing */
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char pr_fname[16]; /* filename of executable */
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char pr_psargs[ELF_PRARGSZ]; /* initial part of arg list */
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};
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#define __STR(x) #x
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#define STR(x) __STR(x)
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#define _GET_SEG(x) \
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({ __u32 seg; asm("movl %%" STR(x) ",%0" : "=r"(seg)); seg; })
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/* Assumes current==process to be dumped */
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#define ELF_CORE_COPY_REGS(pr_reg, regs) \
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pr_reg[0] = regs->rbx; \
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pr_reg[1] = regs->rcx; \
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pr_reg[2] = regs->rdx; \
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pr_reg[3] = regs->rsi; \
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pr_reg[4] = regs->rdi; \
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pr_reg[5] = regs->rbp; \
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pr_reg[6] = regs->rax; \
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pr_reg[7] = _GET_SEG(ds); \
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pr_reg[8] = _GET_SEG(es); \
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pr_reg[9] = _GET_SEG(fs); \
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pr_reg[10] = _GET_SEG(gs); \
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pr_reg[11] = regs->orig_rax; \
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pr_reg[12] = regs->rip; \
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pr_reg[13] = regs->cs; \
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pr_reg[14] = regs->eflags; \
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pr_reg[15] = regs->rsp; \
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pr_reg[16] = regs->ss;
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#define user user32
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#define __ASM_X86_64_ELF_H 1
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#define elf_read_implies_exec(ex, executable_stack) (executable_stack != EXSTACK_DISABLE_X)
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//#include <asm/ia32.h>
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#include <linux/elf.h>
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typedef struct user_i387_ia32_struct elf_fpregset_t;
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typedef struct user32_fxsr_struct elf_fpxregset_t;
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static inline void elf_core_copy_regs(elf_gregset_t *elfregs, struct pt_regs *regs)
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{
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ELF_CORE_COPY_REGS((*elfregs), regs)
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}
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static inline int elf_core_copy_task_regs(struct task_struct *t, elf_gregset_t* elfregs)
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{
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struct pt_regs *pp = task_pt_regs(t);
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ELF_CORE_COPY_REGS((*elfregs), pp);
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/* fix wrong segments */
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(*elfregs)[7] = t->thread.ds;
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(*elfregs)[9] = t->thread.fsindex;
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(*elfregs)[10] = t->thread.gsindex;
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(*elfregs)[8] = t->thread.es;
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return 1;
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}
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static inline int
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elf_core_copy_task_fpregs(struct task_struct *tsk, struct pt_regs *regs, elf_fpregset_t *fpu)
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{
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struct _fpstate_ia32 *fpstate = (void*)fpu;
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mm_segment_t oldfs = get_fs();
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if (!tsk_used_math(tsk))
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return 0;
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if (!regs)
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regs = task_pt_regs(tsk);
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if (tsk == current)
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unlazy_fpu(tsk);
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set_fs(KERNEL_DS);
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save_i387_ia32(tsk, fpstate, regs, 1);
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/* Correct for i386 bug. It puts the fop into the upper 16bits of
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the tag word (like FXSAVE), not into the fcs*/
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fpstate->cssel |= fpstate->tag & 0xffff0000;
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set_fs(oldfs);
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return 1;
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}
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#define ELF_CORE_COPY_XFPREGS 1
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static inline int
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elf_core_copy_task_xfpregs(struct task_struct *t, elf_fpxregset_t *xfpu)
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{
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struct pt_regs *regs = task_pt_regs(t);
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if (!tsk_used_math(t))
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return 0;
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if (t == current)
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unlazy_fpu(t);
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memcpy(xfpu, &t->thread.i387.fxsave, sizeof(elf_fpxregset_t));
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xfpu->fcs = regs->cs;
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xfpu->fos = t->thread.ds; /* right? */
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return 1;
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}
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#undef elf_check_arch
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#define elf_check_arch(x) \
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((x)->e_machine == EM_386)
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extern int force_personality32;
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#define ELF_EXEC_PAGESIZE PAGE_SIZE
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#define ELF_HWCAP (boot_cpu_data.x86_capability[0])
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#define ELF_PLATFORM ("i686")
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#define SET_PERSONALITY(ex, ibcs2) \
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do { \
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unsigned long new_flags = 0; \
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if ((ex).e_ident[EI_CLASS] == ELFCLASS32) \
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new_flags = _TIF_IA32; \
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if ((current_thread_info()->flags & _TIF_IA32) \
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!= new_flags) \
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set_thread_flag(TIF_ABI_PENDING); \
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else \
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clear_thread_flag(TIF_ABI_PENDING); \
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/* XXX This overwrites the user set personality */ \
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current->personality |= force_personality32; \
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} while (0)
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/* Override some function names */
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#define elf_format elf32_format
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#define init_elf_binfmt init_elf32_binfmt
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#define exit_elf_binfmt exit_elf32_binfmt
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#define load_elf_binary load_elf32_binary
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#define ELF_PLAT_INIT(r, load_addr) elf32_init(r)
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#define setup_arg_pages(bprm, stack_top, exec_stack) \
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ia32_setup_arg_pages(bprm, stack_top, exec_stack)
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int ia32_setup_arg_pages(struct linux_binprm *bprm, unsigned long stack_top, int executable_stack);
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#undef start_thread
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#define start_thread(regs,new_rip,new_rsp) do { \
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asm volatile("movl %0,%%fs" :: "r" (0)); \
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asm volatile("movl %0,%%es; movl %0,%%ds": :"r" (__USER32_DS)); \
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load_gs_index(0); \
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(regs)->rip = (new_rip); \
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(regs)->rsp = (new_rsp); \
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(regs)->eflags = 0x200; \
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(regs)->cs = __USER32_CS; \
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(regs)->ss = __USER32_DS; \
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set_fs(USER_DS); \
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} while(0)
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#include <linux/module.h>
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MODULE_DESCRIPTION("Binary format loader for compatibility with IA32 ELF binaries.");
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MODULE_AUTHOR("Eric Youngdale, Andi Kleen");
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#undef MODULE_DESCRIPTION
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#undef MODULE_AUTHOR
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#define elf_addr_t __u32
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static void elf32_init(struct pt_regs *);
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#define ARCH_HAS_SETUP_ADDITIONAL_PAGES 1
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#define arch_setup_additional_pages syscall32_setup_pages
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extern int syscall32_setup_pages(struct linux_binprm *, int exstack);
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#include "../../../fs/binfmt_elf.c"
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static void elf32_init(struct pt_regs *regs)
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{
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struct task_struct *me = current;
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regs->rdi = 0;
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regs->rsi = 0;
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regs->rdx = 0;
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regs->rcx = 0;
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regs->rax = 0;
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regs->rbx = 0;
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regs->rbp = 0;
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regs->r8 = regs->r9 = regs->r10 = regs->r11 = regs->r12 =
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regs->r13 = regs->r14 = regs->r15 = 0;
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me->thread.fs = 0;
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me->thread.gs = 0;
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me->thread.fsindex = 0;
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me->thread.gsindex = 0;
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me->thread.ds = __USER_DS;
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me->thread.es = __USER_DS;
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}
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int ia32_setup_arg_pages(struct linux_binprm *bprm, unsigned long stack_top,
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int executable_stack)
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{
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unsigned long stack_base;
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struct vm_area_struct *mpnt;
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struct mm_struct *mm = current->mm;
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int i, ret;
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stack_base = stack_top - MAX_ARG_PAGES * PAGE_SIZE;
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mm->arg_start = bprm->p + stack_base;
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bprm->p += stack_base;
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if (bprm->loader)
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bprm->loader += stack_base;
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bprm->exec += stack_base;
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mpnt = kmem_cache_alloc(vm_area_cachep, SLAB_KERNEL);
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if (!mpnt)
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return -ENOMEM;
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memset(mpnt, 0, sizeof(*mpnt));
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down_write(&mm->mmap_sem);
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{
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mpnt->vm_mm = mm;
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mpnt->vm_start = PAGE_MASK & (unsigned long) bprm->p;
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mpnt->vm_end = stack_top;
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if (executable_stack == EXSTACK_ENABLE_X)
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mpnt->vm_flags = VM_STACK_FLAGS | VM_EXEC;
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else if (executable_stack == EXSTACK_DISABLE_X)
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mpnt->vm_flags = VM_STACK_FLAGS & ~VM_EXEC;
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else
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mpnt->vm_flags = VM_STACK_FLAGS;
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mpnt->vm_page_prot = (mpnt->vm_flags & VM_EXEC) ?
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PAGE_COPY_EXEC : PAGE_COPY;
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if ((ret = insert_vm_struct(mm, mpnt))) {
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up_write(&mm->mmap_sem);
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kmem_cache_free(vm_area_cachep, mpnt);
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return ret;
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}
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mm->stack_vm = mm->total_vm = vma_pages(mpnt);
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}
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for (i = 0 ; i < MAX_ARG_PAGES ; i++) {
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struct page *page = bprm->page[i];
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if (page) {
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bprm->page[i] = NULL;
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install_arg_page(mpnt, page, stack_base);
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}
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stack_base += PAGE_SIZE;
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}
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up_write(&mm->mmap_sem);
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return 0;
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}
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EXPORT_SYMBOL(ia32_setup_arg_pages);
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#ifdef CONFIG_SYSCTL
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/* Register vsyscall32 into the ABI table */
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#include <linux/sysctl.h>
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static ctl_table abi_table2[] = {
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{ 99, "vsyscall32", &sysctl_vsyscall32, sizeof(int), 0644, NULL,
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proc_dointvec },
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{ 0, }
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};
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static ctl_table abi_root_table2[] = {
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{ .ctl_name = CTL_ABI, .procname = "abi", .mode = 0555,
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.child = abi_table2 },
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{ 0 },
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};
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static __init int ia32_binfmt_init(void)
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{
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register_sysctl_table(abi_root_table2, 1);
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return 0;
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}
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__initcall(ia32_binfmt_init);
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#endif
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