kpriv/linux-hardened
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity

x86, traps, i386: factor out lazy io-bitmap copy

Browse source 
x86_64 does not do the lazy io-bitmap dance. Putting it in
its own function makes i386's do_general_protection look
much more like x86_64's.

Signed-off-by: Alexander van Heukelum <heukelum@fastmail.fm>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Alexander van Heukelum 2008-09-30 18:41:35 +02:00 committed by Ingo Molnar
parent a28680b4b8
commit ae82157b3d
1 changed files with 43 additions and 33 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

76
arch/x86/kernel/traps_32.c
View file

@ -95,6 +95,47 @@ die_if_kernel(const char *str, struct pt_regs *regs, long err)
die(str, regs, err);
}
/*
* Perform the lazy TSS's I/O bitmap copy. If the TSS has an
* invalid offset set (the LAZY one) and the faulting thread has
* a valid I/O bitmap pointer, we copy the I/O bitmap in the TSS,
* we set the offset field correctly and return 1.
*/
static int lazy_iobitmap_copy(void)
{
struct thread_struct *thread;
struct tss_struct *tss;
int cpu;
cpu = get_cpu();
tss = &per_cpu(init_tss, cpu);
thread = &current->thread;
if (tss->x86_tss.io_bitmap_base == INVALID_IO_BITMAP_OFFSET_LAZY &&
thread->io_bitmap_ptr) {
memcpy(tss->io_bitmap, thread->io_bitmap_ptr,
thread->io_bitmap_max);
/*
* If the previously set map was extending to higher ports
* than the current one, pad extra space with 0xff (no access).
*/
if (thread->io_bitmap_max < tss->io_bitmap_max) {
memset((char *) tss->io_bitmap +
thread->io_bitmap_max, 0xff,
tss->io_bitmap_max - thread->io_bitmap_max);
}
tss->io_bitmap_max = thread->io_bitmap_max;
tss->x86_tss.io_bitmap_base = IO_BITMAP_OFFSET;
tss->io_bitmap_owner = thread;
put_cpu();
return 1;
}
put_cpu();
return 0;
}
static void __kprobes
do_trap(int trapnr, int signr, char *str, struct pt_regs *regs,
long error_code, siginfo_t *info)
@ -187,44 +228,13 @@ void __kprobes
do_general_protection(struct pt_regs *regs, long error_code)
{
struct task_struct *tsk;
struct thread_struct *thread;
struct tss_struct *tss;
int cpu;
conditional_sti(regs);
cpu = get_cpu();
tss = &per_cpu(init_tss, cpu);
thread = &current->thread;
/*
* Perform the lazy TSS's I/O bitmap copy. If the TSS has an
* invalid offset set (the LAZY one) and the faulting thread has
* a valid I/O bitmap pointer, we copy the I/O bitmap in the TSS
* and we set the offset field correctly. Then we let the CPU to
* restart the faulting instruction.
*/
if (tss->x86_tss.io_bitmap_base == INVALID_IO_BITMAP_OFFSET_LAZY &&
thread->io_bitmap_ptr) {
memcpy(tss->io_bitmap, thread->io_bitmap_ptr,
thread->io_bitmap_max);
/*
* If the previously set map was extending to higher ports
* than the current one, pad extra space with 0xff (no access).
*/
if (thread->io_bitmap_max < tss->io_bitmap_max) {
memset((char *) tss->io_bitmap +
thread->io_bitmap_max, 0xff,
tss->io_bitmap_max - thread->io_bitmap_max);
}
tss->io_bitmap_max = thread->io_bitmap_max;
tss->x86_tss.io_bitmap_base = IO_BITMAP_OFFSET;
tss->io_bitmap_owner = thread;
put_cpu();
if (lazy_iobitmap_copy()) {
/* restart the faulting instruction */
return;
}
put_cpu();
if (regs->flags & X86_VM_MASK)
goto gp_in_vm86;