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authorAlexander van Heukelum <heukelum@fastmail.fm>2008-09-30 18:41:35 +0200
committerIngo Molnar <mingo@elte.hu>2008-10-13 10:33:19 +0200
commitae82157b3d8bb4902f76b56c7450a945288786ac (patch)
tree5148bdb03b75278e1bb9c28458baf8e9df3e623b /arch/x86
parenta28680b4b821a262fd3b5e57a28c148b5f9e662a (diff)
x86, traps, i386: factor out lazy io-bitmap copy
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>
Diffstat (limited to 'arch/x86')
-rw-r--r--arch/x86/kernel/traps_32.c76
1 files changed, 43 insertions, 33 deletions
diff --git a/arch/x86/kernel/traps_32.c b/arch/x86/kernel/traps_32.c
index ce1063c141f..0206c915748 100644
--- a/arch/x86/kernel/traps_32.c
+++ b/arch/x86/kernel/traps_32.c
@@ -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;