diff options
| author | Brian Gerst <brgerst@gmail.com> | 2015-07-29 08:41:19 +0300 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2015-07-31 14:31:09 +0300 |
| commit | 5ed92a8ab71f8865ba07811429c988c72299b315 (patch) | |
| tree | 30e8cd33bd97ca0c0b7a835e11b6ab41657c7356 /arch/x86/include | |
| parent | 90c6085a248f8f964588617f51329688bcc9f2bc (diff) | |
| download | linux-5ed92a8ab71f8865ba07811429c988c72299b315.tar.xz | |
x86/vm86: Use the normal pt_regs area for vm86
Change to use the normal pt_regs area to enter and exit vm86
mode. This is done by increasing the padding at the top of the
stack to make room for the extra vm86 segment slots in the IRET
frame. It then saves the 32-bit regs in the off-stack vm86
data, and copies in the vm86 regs. Exiting back to 32-bit mode
does the reverse. This allows removing the hacks to jump
directly into the exit asm code due to having to change the
stack pointer. Returning normally from the vm86 syscall and the
exception handlers allows things like ptrace and auditing to work properly.
Signed-off-by: Brian Gerst <brgerst@gmail.com>
Acked-by: Andy Lutomirski <luto@kernel.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1438148483-11932-5-git-send-email-brgerst@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86/include')
| -rw-r--r-- | arch/x86/include/asm/thread_info.h | 11 | ||||
| -rw-r--r-- | arch/x86/include/asm/vm86.h | 6 |
2 files changed, 11 insertions, 6 deletions
diff --git a/arch/x86/include/asm/thread_info.h b/arch/x86/include/asm/thread_info.h index 225ee545e1a0..fdad5c244350 100644 --- a/arch/x86/include/asm/thread_info.h +++ b/arch/x86/include/asm/thread_info.h @@ -27,14 +27,17 @@ * Without this offset, that can result in a page fault. (We are * careful that, in this case, the value we read doesn't matter.) * - * In vm86 mode, the hardware frame is much longer still, but we neither - * access the extra members from NMI context, nor do we write such a - * frame at sp0 at all. + * In vm86 mode, the hardware frame is much longer still, so add 16 + * bytes to make room for the real-mode segments. * * x86_64 has a fixed-length stack frame. */ #ifdef CONFIG_X86_32 -# define TOP_OF_KERNEL_STACK_PADDING 8 +# ifdef CONFIG_VM86 +# define TOP_OF_KERNEL_STACK_PADDING 16 +# else +# define TOP_OF_KERNEL_STACK_PADDING 8 +# endif #else # define TOP_OF_KERNEL_STACK_PADDING 0 #endif diff --git a/arch/x86/include/asm/vm86.h b/arch/x86/include/asm/vm86.h index 226d6c157ebc..e45386eee17a 100644 --- a/arch/x86/include/asm/vm86.h +++ b/arch/x86/include/asm/vm86.h @@ -29,7 +29,7 @@ struct kernel_vm86_regs { struct vm86 { struct vm86plus_struct __user *vm86_info; - struct pt_regs *regs32; + struct pt_regs regs32; unsigned long v86flags; unsigned long v86mask; unsigned long saved_sp0; @@ -46,7 +46,7 @@ struct vm86 { void handle_vm86_fault(struct kernel_vm86_regs *, long); int handle_vm86_trap(struct kernel_vm86_regs *, long, int); -struct pt_regs *save_v86_state(struct kernel_vm86_regs *); +void save_v86_state(struct kernel_vm86_regs *, int); struct task_struct; void release_vm86_irqs(struct task_struct *); @@ -69,6 +69,8 @@ static inline int handle_vm86_trap(struct kernel_vm86_regs *a, long b, int c) return 0; } +static inline void save_v86_state(struct kernel_vm86_regs *a, int b) { } + #define free_vm86(t) do { } while(0) #endif /* CONFIG_VM86 */ |