Skip to content

Commit

Permalink
x86_64/vsyscall: Move all of the gate_area code to vsyscall_64.c
Browse files Browse the repository at this point in the history
This code exists for the sole purpose of making the vsyscall
page look sort of like real userspace memory.  Move it so that
it lives with the rest of the vsyscall code.

Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Link: http://lkml.kernel.org/r/a7ee266773671a05f00b7175ca65a0dd812d2e4b.1411494540.git.luto@amacapital.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
  • Loading branch information
Andy Lutomirski authored and Ingo Molnar committed Oct 28, 2014
1 parent cac7f24 commit b935909
Show file tree
Hide file tree
Showing 2 changed files with 49 additions and 49 deletions.
49 changes: 49 additions & 0 deletions arch/x86/kernel/vsyscall_64.c
Original file line number Diff line number Diff line change
Expand Up @@ -283,6 +283,55 @@ bool emulate_vsyscall(struct pt_regs *regs, unsigned long address)
return true;
}

/*
* A pseudo VMA to allow ptrace access for the vsyscall page. This only
* covers the 64bit vsyscall page now. 32bit has a real VMA now and does
* not need special handling anymore:
*/
static const char *gate_vma_name(struct vm_area_struct *vma)
{
return "[vsyscall]";
}
static struct vm_operations_struct gate_vma_ops = {
.name = gate_vma_name,
};
static struct vm_area_struct gate_vma = {
.vm_start = VSYSCALL_ADDR,
.vm_end = VSYSCALL_ADDR + PAGE_SIZE,
.vm_page_prot = PAGE_READONLY_EXEC,
.vm_flags = VM_READ | VM_EXEC,
.vm_ops = &gate_vma_ops,
};

struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
{
#ifdef CONFIG_IA32_EMULATION
if (!mm || mm->context.ia32_compat)
return NULL;
#endif
return &gate_vma;
}

int in_gate_area(struct mm_struct *mm, unsigned long addr)
{
struct vm_area_struct *vma = get_gate_vma(mm);

if (!vma)
return 0;

return (addr >= vma->vm_start) && (addr < vma->vm_end);
}

/*
* Use this when you have no reliable mm, typically from interrupt
* context. It is less reliable than using a task's mm and may give
* false positives.
*/
int in_gate_area_no_mm(unsigned long addr)
{
return (addr & PAGE_MASK) == VSYSCALL_ADDR;
}

/*
* Assume __initcall executes before all user space. Hopefully kmod
* doesn't violate that. We'll find out if it does.
Expand Down
49 changes: 0 additions & 49 deletions arch/x86/mm/init_64.c
Original file line number Diff line number Diff line change
Expand Up @@ -1193,55 +1193,6 @@ int kern_addr_valid(unsigned long addr)
return pfn_valid(pte_pfn(*pte));
}

/*
* A pseudo VMA to allow ptrace access for the vsyscall page. This only
* covers the 64bit vsyscall page now. 32bit has a real VMA now and does
* not need special handling anymore:
*/
static const char *gate_vma_name(struct vm_area_struct *vma)
{
return "[vsyscall]";
}
static struct vm_operations_struct gate_vma_ops = {
.name = gate_vma_name,
};
static struct vm_area_struct gate_vma = {
.vm_start = VSYSCALL_ADDR,
.vm_end = VSYSCALL_ADDR + PAGE_SIZE,
.vm_page_prot = PAGE_READONLY_EXEC,
.vm_flags = VM_READ | VM_EXEC,
.vm_ops = &gate_vma_ops,
};

struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
{
#ifdef CONFIG_IA32_EMULATION
if (!mm || mm->context.ia32_compat)
return NULL;
#endif
return &gate_vma;
}

int in_gate_area(struct mm_struct *mm, unsigned long addr)
{
struct vm_area_struct *vma = get_gate_vma(mm);

if (!vma)
return 0;

return (addr >= vma->vm_start) && (addr < vma->vm_end);
}

/*
* Use this when you have no reliable mm, typically from interrupt
* context. It is less reliable than using a task's mm and may give
* false positives.
*/
int in_gate_area_no_mm(unsigned long addr)
{
return (addr & PAGE_MASK) == VSYSCALL_ADDR;
}

static unsigned long probe_memory_block_size(void)
{
/* start from 2g */
Expand Down

0 comments on commit b935909

Please sign in to comment.