diff options
| author |   Ingo Molnar <mingo@kernel.org> | 2015-03-29 11:02:34 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2015-03-31 11:45:19 +0200 |
| commit | 55474c48b4726fd3914c1ec47fced0f931729979 (patch) | |
| tree | cf2905156f4adad351dbd3195179deb939e24c73 /arch/x86/kernel/traps.c | |
| parent | x86/asm/entry/64: Do not GET_THREAD_INFO() too early (diff) | |
| download | linux-dev-55474c48b4726fd3914c1ec47fced0f931729979.tar.xz linux-dev-55474c48b4726fd3914c1ec47fced0f931729979.zip | |
x86/asm/entry: Remove user_mode_ignore_vm86()
user_mode_ignore_vm86() can be used instead of user_mode(), in
places where we have already done a v8086_mode() security
check of ptregs.
But doing this check in the wrong place would be a bug that
could result in security problems, and also the naming still
isn't very clear.
Furthermore, it only affects 32-bit kernels, while most
development happens on 64-bit kernels.
If we replace them with user_mode() checks then the cost is only
a very minor increase in various slowpaths:
text data bss dec hex filename
10573391 703562 1753042 13029995 c6d26b vmlinux.o.before
10573423 703562 1753042 13030027 c6d28b vmlinux.o.after
So lets get rid of this distinction once and for all.
Acked-by: Borislav Petkov <bp@suse.de>
Acked-by: Andy Lutomirski <luto@kernel.org>
Cc: Andrew Lutomirski <luto@kernel.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brad Spengler <spender@grsecurity.net>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20150329090233.GA1963@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86/kernel/traps.c')
| -rw-r--r-- | arch/x86/kernel/traps.c | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c index c8eb469a94a4..6751c5c58eec 100644 --- a/arch/x86/kernel/traps.c +++ b/arch/x86/kernel/traps.c @@ -207,7 +207,7 @@ do_trap_no_signal(struct task_struct *tsk, int trapnr, char *str, return -1; } - if (!user_mode_ignore_vm86(regs)) { + if (!user_mode(regs)) { if (!fixup_exception(regs)) { tsk->thread.error_code = error_code; tsk->thread.trap_nr = trapnr; @@ -468,7 +468,7 @@ do_general_protection(struct pt_regs *regs, long error_code) } tsk = current; - if (!user_mode_ignore_vm86(regs)) { + if (!user_mode(regs)) { if (fixup_exception(regs)) goto exit; @@ -685,7 +685,7 @@ dotraplinkage void do_debug(struct pt_regs *regs, long error_code) * We already checked v86 mode above, so we can check for kernel mode * by just checking the CPL of CS. */ - if ((dr6 & DR_STEP) && !user_mode_ignore_vm86(regs)) { + if ((dr6 & DR_STEP) && !user_mode(regs)) { tsk->thread.debugreg6 &= ~DR_STEP; set_tsk_thread_flag(tsk, TIF_SINGLESTEP); regs->flags &= ~X86_EFLAGS_TF; |