CVS commit: [netbsd-8] src/sys/arch/x86/x86

["Martin Husemann" <martin%netbsd.org@localhost>]

Module Name:    src
Committed By:   martin
Date:           Thu Apr 12 13:08:16 UTC 2018

Modified Files:
        src/sys/arch/x86/x86 [netbsd-8]: dbregs.c

Log Message:
Pull up following revision(s) (requested by kamil in ticket #712):

        sys/arch/x86/x86/dbregs.c: revision 1.7-1.9

Fix the check, should be >=.

Hum, don't let userland set bit 13, because this can crash the kernel.

Add paranoid code to X86 Debug Registers

Reset certain bits in DR6 and DR7 in x86_dbregs_setup_initdbstate().
Reset X86_BREAKPOINT_CONDITION_DETECTED in DR6.
Reset X86_DR7_GENERAL_DETECT_ENABLE in DR7.

It's allowed by devices or software before the kernel boot, to
use these registers for their own purposes. Handle this paranoid case
explicitly setting the mentioned bits to zero.

Sponsored by <The NetBSD Foundation>


To generate a diff of this commit:
cvs rdiff -u -r1.6 -r1.6.6.1 src/sys/arch/x86/x86/dbregs.c

Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.