c56004901f
This adds VM op batching to skas0. Rather than having a context switch to and from the userspace stub for each address space change, we write a number of operations to the stub data page and invoke a different stub which loops over them and executes them all in one go. The operations are stored as [ system call number, arg1, arg2, ... ] tuples. The set is terminated by a system call number of 0. Single operations, i.e. page faults, are handled in the old way, since that is slightly more efficient. For a kernel build, a minority (~1/4) of the operations are part of a set. These sets averaged ~100 in length, so for this quarter, the context switching overhead is greatly reduced. Signed-off-by: Jeff Dike <jdike@addtoit.com> Cc: Paolo Giarrusso <blaisorblade@yahoo.it> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
240 lines
7.5 KiB
C
240 lines
7.5 KiB
C
/*
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* Copyright (C) 2002 Jeff Dike (jdike@karaya.com)
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* Licensed under the GPL
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*/
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#include <signal.h>
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#include <errno.h>
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#include <sys/mman.h>
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#include <sys/wait.h>
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#include <asm/page.h>
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#include <asm/unistd.h>
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#include "mem_user.h"
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#include "mem.h"
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#include "mm_id.h"
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#include "user.h"
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#include "os.h"
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#include "proc_mm.h"
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#include "ptrace_user.h"
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#include "user_util.h"
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#include "kern_util.h"
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#include "task.h"
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#include "registers.h"
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#include "uml-config.h"
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#include "sysdep/ptrace.h"
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#include "sysdep/stub.h"
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#include "skas.h"
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extern unsigned long syscall_stub, batch_syscall_stub, __syscall_stub_start;
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extern void wait_stub_done(int pid, int sig, char * fname);
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int single_count = 0;
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static long one_syscall_stub(struct mm_id * mm_idp, int syscall,
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unsigned long *args)
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{
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int n, pid = mm_idp->u.pid;
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unsigned long regs[MAX_REG_NR];
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get_safe_registers(regs);
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regs[REGS_IP_INDEX] = UML_CONFIG_STUB_CODE +
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((unsigned long) &syscall_stub -
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(unsigned long) &__syscall_stub_start);
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/* XXX Don't have a define for starting a syscall */
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regs[REGS_SYSCALL_NR] = syscall;
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regs[REGS_SYSCALL_ARG1] = args[0];
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regs[REGS_SYSCALL_ARG2] = args[1];
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regs[REGS_SYSCALL_ARG3] = args[2];
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regs[REGS_SYSCALL_ARG4] = args[3];
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regs[REGS_SYSCALL_ARG5] = args[4];
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regs[REGS_SYSCALL_ARG6] = args[5];
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n = ptrace_setregs(pid, regs);
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if(n < 0){
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printk("one_syscall_stub : PTRACE_SETREGS failed, "
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"errno = %d\n", n);
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return(n);
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}
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wait_stub_done(pid, 0, "one_syscall_stub");
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return(*((unsigned long *) mm_idp->stack));
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}
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int multi_count = 0;
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int multi_op_count = 0;
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static long many_syscall_stub(struct mm_id * mm_idp, int syscall,
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unsigned long *args, int done, void **addr_out)
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{
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unsigned long regs[MAX_REG_NR], *stack;
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int n, pid = mm_idp->u.pid;
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stack = *addr_out;
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if(stack == NULL)
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stack = (unsigned long *) current_stub_stack();
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*stack++ = syscall;
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*stack++ = args[0];
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*stack++ = args[1];
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*stack++ = args[2];
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*stack++ = args[3];
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*stack++ = args[4];
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*stack++ = args[5];
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*stack = 0;
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multi_op_count++;
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if(!done && ((((unsigned long) stack) & ~PAGE_MASK) <
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PAGE_SIZE - 8 * sizeof(long))){
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*addr_out = stack;
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return 0;
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}
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multi_count++;
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get_safe_registers(regs);
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regs[REGS_IP_INDEX] = UML_CONFIG_STUB_CODE +
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((unsigned long) &batch_syscall_stub -
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(unsigned long) &__syscall_stub_start);
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regs[REGS_SP_INDEX] = UML_CONFIG_STUB_DATA;
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n = ptrace_setregs(pid, regs);
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if(n < 0){
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printk("many_syscall_stub : PTRACE_SETREGS failed, "
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"errno = %d\n", n);
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return(n);
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}
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wait_stub_done(pid, 0, "many_syscall_stub");
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stack = (unsigned long *) mm_idp->stack;
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*addr_out = stack;
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return(*stack);
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}
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static long run_syscall_stub(struct mm_id * mm_idp, int syscall,
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unsigned long *args, void **addr, int done)
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{
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long res;
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if((*addr == NULL) && done)
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res = one_syscall_stub(mm_idp, syscall, args);
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else res = many_syscall_stub(mm_idp, syscall, args, done, addr);
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return res;
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}
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void *map(struct mm_id * mm_idp, unsigned long virt, unsigned long len,
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int r, int w, int x, int phys_fd, unsigned long long offset,
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int done, void *data)
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{
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int prot, n;
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prot = (r ? PROT_READ : 0) | (w ? PROT_WRITE : 0) |
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(x ? PROT_EXEC : 0);
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if(proc_mm){
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struct proc_mm_op map;
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int fd = mm_idp->u.mm_fd;
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map = ((struct proc_mm_op) { .op = MM_MMAP,
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.u =
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{ .mmap =
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{ .addr = virt,
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.len = len,
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.prot = prot,
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.flags = MAP_SHARED |
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MAP_FIXED,
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.fd = phys_fd,
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.offset= offset
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} } } );
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n = os_write_file(fd, &map, sizeof(map));
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if(n != sizeof(map))
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printk("map : /proc/mm map failed, err = %d\n", -n);
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}
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else {
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long res;
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unsigned long args[] = { virt, len, prot,
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MAP_SHARED | MAP_FIXED, phys_fd,
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MMAP_OFFSET(offset) };
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res = run_syscall_stub(mm_idp, STUB_MMAP_NR, args,
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&data, done);
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if((void *) res == MAP_FAILED)
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printk("mmap stub failed, errno = %d\n", res);
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}
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return data;
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}
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void *unmap(struct mm_id * mm_idp, void *addr, unsigned long len, int done,
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void *data)
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{
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int n;
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if(proc_mm){
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struct proc_mm_op unmap;
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int fd = mm_idp->u.mm_fd;
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unmap = ((struct proc_mm_op) { .op = MM_MUNMAP,
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.u =
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{ .munmap =
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{ .addr =
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(unsigned long) addr,
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.len = len } } } );
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n = os_write_file(fd, &unmap, sizeof(unmap));
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if(n != sizeof(unmap))
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printk("unmap - proc_mm write returned %d\n", n);
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}
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else {
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int res;
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unsigned long args[] = { (unsigned long) addr, len, 0, 0, 0,
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0 };
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res = run_syscall_stub(mm_idp, __NR_munmap, args,
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&data, done);
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if(res < 0)
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printk("munmap stub failed, errno = %d\n", res);
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}
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return data;
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}
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void *protect(struct mm_id * mm_idp, unsigned long addr, unsigned long len,
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int r, int w, int x, int done, void *data)
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{
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struct proc_mm_op protect;
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int prot, n;
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prot = (r ? PROT_READ : 0) | (w ? PROT_WRITE : 0) |
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(x ? PROT_EXEC : 0);
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if(proc_mm){
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int fd = mm_idp->u.mm_fd;
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protect = ((struct proc_mm_op) { .op = MM_MPROTECT,
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.u =
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{ .mprotect =
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{ .addr =
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(unsigned long) addr,
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.len = len,
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.prot = prot } } } );
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n = os_write_file(fd, &protect, sizeof(protect));
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if(n != sizeof(protect))
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panic("protect failed, err = %d", -n);
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}
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else {
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int res;
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unsigned long args[] = { addr, len, prot, 0, 0, 0 };
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res = run_syscall_stub(mm_idp, __NR_mprotect, args,
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&data, done);
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if(res < 0)
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panic("mprotect stub failed, errno = %d\n", res);
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}
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return data;
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}
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void before_mem_skas(unsigned long unused)
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{
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}
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