x86/signal/64: Remove 'fs' and 'gs' from sigcontext
As far as I can tell, these fields have been set to zero on save
and ignored on restore since Linux was imported into git.
Rename them '__pad1' and '__pad2' to avoid confusion. This may
also allow us to recycle them some day.
This also adds a comment clarifying the history of those fields.
I'm intentionally avoiding calling either of them '__pad0': the
field formerly known as '__pad0' is now 'ss'.
Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Borislav Petkov <bp@alien8.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/844f8490e938780c03355be4c9b69eb4c494bf4e.1426193719.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
diff --git a/arch/x86/include/asm/sigcontext.h b/arch/x86/include/asm/sigcontext.h
index f910cdc..6fe6b18 100644
--- a/arch/x86/include/asm/sigcontext.h
+++ b/arch/x86/include/asm/sigcontext.h
@@ -57,8 +57,8 @@
unsigned long ip;
unsigned long flags;
unsigned short cs;
- unsigned short gs;
- unsigned short fs;
+ unsigned short __pad2; /* Was called gs, but was always zero. */
+ unsigned short __pad1; /* Was called fs, but was always zero. */
unsigned short ss;
unsigned long err;
unsigned long trapno;