commit 296f781a4b7801ad9c1c0219f9e87b6c25e196fe
author Andy Lutomirski <luto@kernel.org> Tue Apr 26 12:23:29 2016 -0700
committer Ingo Molnar <mingo@kernel.org> Fri Apr 29 11:56:42 2016 +0200
tree 6ef66ab7f992aebabaeb40069919d217f35837fb
parent 731e33e39a5b95ad77017811b3ced32ecf9dc666

x86/asm/64: Rename thread_struct's fs and gs to fsbase and gsbase

Unlike ds and es, these are base addresses, not selectors.  Rename
them so their meaning is more obvious.

On x86_32, the field is still called fs.  Fixing that could make sense
as a future cleanup.

Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/69a18a51c4cba0ce29a241e570fc618ad721d908.1461698311.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

arch/x86/include/asm/elf.h

diff --git a/arch/x86/include/asm/elf.h b/arch/x86/include/asm/elf.h
index 15340e3..fea7724 100644
--- a/arch/x86/include/asm/elf.h
+++ b/arch/x86/include/asm/elf.h
@@ -176,7 +176,7 @@
 	regs->si = regs->di = regs->bp = 0;
 	regs->r8 = regs->r9 = regs->r10 = regs->r11 = 0;
 	regs->r12 = regs->r13 = regs->r14 = regs->r15 = 0;
-	t->fs = t->gs = 0;
+	t->fsbase = t->gsbase = 0;
 	t->fsindex = t->gsindex = 0;
 	t->ds = t->es = ds;
 }
@@ -226,8 +226,8 @@
 	(pr_reg)[18] = (regs)->flags;				\
 	(pr_reg)[19] = (regs)->sp;				\
 	(pr_reg)[20] = (regs)->ss;				\
-	(pr_reg)[21] = current->thread.fs;			\
-	(pr_reg)[22] = current->thread.gs;			\
+	(pr_reg)[21] = current->thread.fsbase;			\
+	(pr_reg)[22] = current->thread.gsbase;			\
 	asm("movl %%ds,%0" : "=r" (v)); (pr_reg)[23] = v;	\
 	asm("movl %%es,%0" : "=r" (v)); (pr_reg)[24] = v;	\
 	asm("movl %%fs,%0" : "=r" (v)); (pr_reg)[25] = v;	\

arch/x86/include/asm/processor.h

diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index 9264476..9251aa9 100644
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -388,9 +388,16 @@
 	unsigned long		ip;
 #endif
 #ifdef CONFIG_X86_64
-	unsigned long		fs;
+	unsigned long		fsbase;
+	unsigned long		gsbase;
+#else
+	/*
+	 * XXX: this could presumably be unsigned short.  Alternatively,
+	 * 32-bit kernels could be taught to use fsindex instead.
+	 */
+	unsigned long fs;
+	unsigned long gs;
 #endif
-	unsigned long		gs;
 
 	/* Save middle states of ptrace breakpoints */
 	struct perf_event	*ptrace_bps[HBP_NUM];