x86/asm/32: Make pt_regs's segment registers be 16 bits
authorAndy Lutomirski <luto@kernel.org>
Fri, 28 Jul 2017 13:00:30 +0000 (06:00 -0700)
committerIngo Molnar <mingo@kernel.org>
Sun, 30 Jul 2017 10:04:40 +0000 (12:04 +0200)
commit385eca8f277c4c34f361a4c3a088fd876d29ae21
tree741009fbb9b67a8d6934b087f71b474784cfe107
parent21ec3bf6aeb4033210747837421e63286ba32646
x86/asm/32: Make pt_regs's segment registers be 16 bits

Many 32-bit x86 CPUs do 16-bit writes when storing segment registers to
memory.  This can cause the high word of regs->[cdefgs]s to
occasionally contain garbage.

Rather than making the entry code more complicated to fix up the
garbage, just change pt_regs to reflect reality.

Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Borislav Petkov <bpetkov@suse.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
arch/x86/include/asm/ptrace.h