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Commit ae82157b authored by Alexander van Heukelum's avatar Alexander van Heukelum Committed by Ingo Molnar
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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: default avatarAlexander van Heukelum <heukelum@fastmail.fm>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent a28680b4

arch/x86/kernel/traps_32.c

+43 −33
Original line number Original line Diff line number Diff line
@@ -95,6 +95,47 @@ die_if_kernel(const char *str, struct pt_regs *regs, long err) 
		die(str, regs, 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

static void __kprobes

do_trap(int trapnr, int signr, char *str, struct pt_regs *regs,

do_trap(int trapnr, int signr, char *str, struct pt_regs *regs,

	long error_code, siginfo_t *info)

	long error_code, siginfo_t *info)
@@ -187,44 +228,13 @@ void __kprobes 
do_general_protection(struct pt_regs *regs, long error_code)

do_general_protection(struct pt_regs *regs, long error_code)

{

{

	struct task_struct *tsk;

	struct task_struct *tsk;

	struct thread_struct *thread;

	struct tss_struct *tss;

	int cpu;





	conditional_sti(regs);

	conditional_sti(regs);





	cpu = get_cpu();

	if (lazy_iobitmap_copy()) {

	tss = &per_cpu(init_tss, cpu);

		/* restart the faulting instruction */

	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();



		return;

		return;

	}

	}

	put_cpu();





	if (regs->flags & X86_VM_MASK)

	if (regs->flags & X86_VM_MASK)

		goto gp_in_vm86;

		goto gp_in_vm86;