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https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
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8ece53ef7f
The implementation was rather buggy. It unconditionally marked PTEs read-only, even for VM_SHARED mappings. I'm not sure whether this is actually a problem, but it certainly seems unwise. More importantly, it released the mmap lock before flushing the TLB, which could allow a racing CoW operation to falsely believe that the underlying memory was not writable. I can't find any users at all of this mechanism, so just remove it. Signed-off-by: Andy Lutomirski <luto@kernel.org> Signed-off-by: Borislav Petkov <bp@suse.de> Acked-by: Stas Sergeev <stsp2@yandex.ru> Link: https://lkml.kernel.org/r/f3086de0babcab36f69949b5780bde851f719bc8.1611078018.git.luto@kernel.org
91 lines
2.1 KiB
C
91 lines
2.1 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _ASM_X86_VM86_H
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#define _ASM_X86_VM86_H
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#include <asm/ptrace.h>
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#include <uapi/asm/vm86.h>
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/*
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* This is the (kernel) stack-layout when we have done a "SAVE_ALL" from vm86
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* mode - the main change is that the old segment descriptors aren't
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* useful any more and are forced to be zero by the kernel (and the
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* hardware when a trap occurs), and the real segment descriptors are
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* at the end of the structure. Look at ptrace.h to see the "normal"
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* setup. For user space layout see 'struct vm86_regs' above.
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*/
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struct kernel_vm86_regs {
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/*
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* normal regs, with special meaning for the segment descriptors..
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*/
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struct pt_regs pt;
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/*
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* these are specific to v86 mode:
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*/
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unsigned short es, __esh;
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unsigned short ds, __dsh;
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unsigned short fs, __fsh;
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unsigned short gs, __gsh;
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};
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struct vm86 {
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struct vm86plus_struct __user *user_vm86;
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struct pt_regs regs32;
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unsigned long veflags;
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unsigned long veflags_mask;
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unsigned long saved_sp0;
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unsigned long flags;
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unsigned long cpu_type;
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struct revectored_struct int_revectored;
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struct revectored_struct int21_revectored;
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struct vm86plus_info_struct vm86plus;
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};
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#ifdef CONFIG_VM86
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void handle_vm86_fault(struct kernel_vm86_regs *, long);
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int handle_vm86_trap(struct kernel_vm86_regs *, long, int);
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void save_v86_state(struct kernel_vm86_regs *, int);
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struct task_struct;
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#define free_vm86(t) do { \
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struct thread_struct *__t = (t); \
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if (__t->vm86 != NULL) { \
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kfree(__t->vm86); \
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__t->vm86 = NULL; \
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} \
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} while (0)
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/*
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* Support for VM86 programs to request interrupts for
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* real mode hardware drivers:
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*/
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#define FIRST_VM86_IRQ 3
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#define LAST_VM86_IRQ 15
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static inline int invalid_vm86_irq(int irq)
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{
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return irq < FIRST_VM86_IRQ || irq > LAST_VM86_IRQ;
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}
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void release_vm86_irqs(struct task_struct *);
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#else
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#define handle_vm86_fault(a, b)
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#define release_vm86_irqs(a)
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static inline int handle_vm86_trap(struct kernel_vm86_regs *a, long b, int c)
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{
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return 0;
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}
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static inline void save_v86_state(struct kernel_vm86_regs *a, int b) { }
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#define free_vm86(t) do { } while(0)
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#endif /* CONFIG_VM86 */
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#endif /* _ASM_X86_VM86_H */
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