linux/arch/um/kernel/exec.c

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/*
* Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
* Licensed under the GPL
*/
#include "linux/stddef.h"
#include "linux/fs.h"
#include "linux/smp_lock.h"
#include "linux/ptrace.h"
#include "linux/sched.h"
#include "asm/current.h"
#include "asm/processor.h"
#include "asm/uaccess.h"
uml: fix stub address calculations The calculation of CONFIG_STUB_CODE and CONFIG_STUB_DATA didn't take into account anything but 3G/1G and 2G/2G, leaving the other vmsplits out in the cold. I'd rather not duplicate the four known host vmsplit cases for each of these symbols. I'd also like to calculate them based on the highest userspace address. The Kconfig language seems not to allow calculation of hex constants, so I moved this to as-layout.h. CONFIG_STUB_CODE, CONFIG_STUB_DATA, and CONFIG_STUB_START are now gone. In their place are STUB_CODE, STUB_DATA, and STUB_START in as-layout.h. i386 and x86_64 seem to differ as to whether an unadorned constant is an int or a long, so I cast them to unsigned long so they can be printed consistently. However, they are also used in stub.S, where C types don't work so well. So, there are ASM_ versions of these constants for use in stub.S. I also ifdef-ed the non-asm-friendly portion of as-layout.h. With this in place, most of the rest of this patch is changing CONFIG_STUB_* to STUB_*, except in stub.S, where they are changed to ASM_STUB_*. defconfig has the old symbols deleted. I also print these addresses out in case there is any problem mapping them on the host. The two stub.S files had some trailing whitespace, so that is cleaned up here. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Jeff Dike <jdike@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-16 08:27:33 +00:00
#include "as-layout.h"
#include "mem_user.h"
#include "skas.h"
#include "os.h"
#include "internal.h"
void flush_thread(void)
{
void *data = NULL;
int ret;
arch_flush_thread(&current->thread.arch);
uml: cover stubs with a VMA Give the stubs a VMA. This allows the removal of a truly nasty kludge to make sure that mm->nr_ptes was correct in exit_mmap. The underlying problem was always that the stubs, which have ptes, and thus allocated a page table, weren't covered by a VMA. This patch fixes that by using install_special_mapping in arch_dup_mmap and activate_context to create the VMA. The stubs have to be moved, since shift_arg_pages seems to assume that the stack is the only VMA present at that point during exec, and uses vma_adjust to fiddle its VMA. However, that extends the stub VMA by the amount removed from the stack VMA. To avoid this problem, the stubs were moved to a different fixed location at the start of the address space. The init_stub_pte calls were moved from init_new_context to arch_dup_mmap because I was occasionally seeing arch_dup_mmap not being called, causing exit_mmap to die. Rather than figure out what was really happening, I decided it was cleaner to just move the calls so that there's no doubt that both the pte and VMA creation happen, no matter what. arch_exit_mmap is used to clear the stub ptes at exit time. The STUB_* constants in as-layout.h no longer depend on UM_TASK_SIZE, that that definition is removed, along with the comments complaining about gcc. Because the stubs are no longer at the top of the address space, some care is needed while flushing TLBs. update_pte_range checks for addresses in the stub range and skips them. flush_thread now issues two unmaps, one for the range before STUB_START and one for the range after STUB_END. Signed-off-by: Jeff Dike <jdike@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-05 06:31:01 +00:00
ret = unmap(&current->mm->context.id, 0, STUB_START, 0, &data);
ret = ret || unmap(&current->mm->context.id, STUB_END,
host_task_size - STUB_END, 1, &data);
if (ret) {
printk(KERN_ERR "flush_thread - clearing address space failed, "
"err = %d\n", ret);
force_sig(SIGKILL, current);
}
__switch_mm(&current->mm->context.id);
}
void start_thread(struct pt_regs *regs, unsigned long eip, unsigned long esp)
{
set_fs(USER_DS);
PT_REGS_IP(regs) = eip;
PT_REGS_SP(regs) = esp;
}
static long execve1(char *file, char __user * __user *argv,
char __user *__user *env)
{
long error;
error = do_execve(file, argv, env, &current->thread.regs);
if (error == 0) {
task_lock(current);
current->ptrace &= ~PT_DTRACE;
#ifdef SUBARCH_EXECVE1
SUBARCH_EXECVE1(&current->thread.regs.regs);
#endif
task_unlock(current);
}
return error;
}
long um_execve(char *file, char __user *__user *argv, char __user *__user *env)
{
long err;
err = execve1(file, argv, env);
if (!err)
UML_LONGJMP(current->thread.exec_buf, 1);
return err;
}
long sys_execve(char __user *file, char __user *__user *argv,
char __user *__user *env)
{
long error;
char *filename;
lock_kernel();
filename = getname(file);
error = PTR_ERR(filename);
if (IS_ERR(filename)) goto out;
error = execve1(filename, argv, env);
putname(filename);
out:
unlock_kernel();
return error;
}