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>

diff --git a/arch/x86/kernel/traps_32.c b/arch/x86/kernel/traps_32.c
index ce1063c141fcbcafa5e3c474c98edd8c117b4c1d..0206c915748cc5c346c8cb5df5347fd75ea57b43 100644 (file)
--- 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;