From 8ece53ef7f428ee3f8eab936268b1a3fe2725e6b Mon Sep 17 00:00:00 2001 From: Andy Lutomirski Date: Tue, 19 Jan 2021 09:40:55 -0800 Subject: x86/vm86/32: Remove VM86_SCREEN_BITMAP support 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 Signed-off-by: Borislav Petkov Acked-by: Stas Sergeev Link: https://lkml.kernel.org/r/f3086de0babcab36f69949b5780bde851f719bc8.1611078018.git.luto@kernel.org --- arch/x86/include/asm/vm86.h | 1 - 1 file changed, 1 deletion(-) (limited to 'arch/x86/include/asm/vm86.h') diff --git a/arch/x86/include/asm/vm86.h b/arch/x86/include/asm/vm86.h index 26efbec94448..9e8ac5073ecb 100644 --- a/arch/x86/include/asm/vm86.h +++ b/arch/x86/include/asm/vm86.h @@ -36,7 +36,6 @@ struct vm86 { unsigned long saved_sp0; unsigned long flags; - unsigned long screen_bitmap; unsigned long cpu_type; struct revectored_struct int_revectored; struct revectored_struct int21_revectored; -- cgit