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

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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>
This commit is contained in:
Andy Lutomirski
2016-04-26 12:23:29 -07:00
committed by Ingo Molnar
parent 731e33e39a
commit 296f781a4b
5 changed files with 32 additions and 25 deletions
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30
arch/x86/kernel/process_64.c
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@@ -150,9 +150,9 @@ int copy_thread_tls(unsigned long clone_flags, unsigned long sp,
p->thread.io_bitmap_ptr = NULL;
savesegment(gs, p->thread.gsindex);
p->thread.gs = p->thread.gsindex ? 0 : me->thread.gs;
p->thread.gsbase = p->thread.gsindex ? 0 : me->thread.gsbase;
savesegment(fs, p->thread.fsindex);
p->thread.fs = p->thread.fsindex ? 0 : me->thread.fs;
p->thread.fsbase = p->thread.fsindex ? 0 : me->thread.fsbase;
savesegment(es, p->thread.es);
savesegment(ds, p->thread.ds);
memset(p->thread.ptrace_bps, 0, sizeof(p->thread.ptrace_bps));
@@ -329,18 +329,18 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p)
* stronger guarantees.)
*
* As an invariant,
* (fs != 0 && fsindex != 0) || (gs != 0 && gsindex != 0) is
* (fsbase != 0 && fsindex != 0) || (gsbase != 0 && gsindex != 0) is
* impossible.
*/
if (next->fsindex) {
/* Loading a nonzero value into FS sets the index and base. */
loadsegment(fs, next->fsindex);
} else {
if (next->fs) {
if (next->fsbase) {
/* Next index is zero but next base is nonzero. */
if (prev_fsindex)
loadsegment(fs, 0);
wrmsrl(MSR_FS_BASE, next->fs);
wrmsrl(MSR_FS_BASE, next->fsbase);
} else {
/* Next base and index are both zero. */
if (static_cpu_has_bug(X86_BUG_NULL_SEG)) {
@@ -356,7 +356,7 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p)
* didn't change the base, then the base is
* also zero and we don't need to do anything.
*/
if (prev->fs || prev_fsindex)
if (prev->fsbase || prev_fsindex)
loadsegment(fs, 0);
}
}
@@ -369,18 +369,18 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p)
* us.
*/
if (prev_fsindex)
prev->fs = 0;
prev->fsbase = 0;
prev->fsindex = prev_fsindex;
if (next->gsindex) {
/* Loading a nonzero value into GS sets the index and base. */
load_gs_index(next->gsindex);
} else {
if (next->gs) {
if (next->gsbase) {
/* Next index is zero but next base is nonzero. */
if (prev_gsindex)
load_gs_index(0);
wrmsrl(MSR_KERNEL_GS_BASE, next->gs);
wrmsrl(MSR_KERNEL_GS_BASE, next->gsbase);
} else {
/* Next base and index are both zero. */
if (static_cpu_has_bug(X86_BUG_NULL_SEG)) {
@@ -400,7 +400,7 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p)
* didn't change the base, then the base is
* also zero and we don't need to do anything.
*/
if (prev->gs || prev_gsindex)
if (prev->gsbase || prev_gsindex)
load_gs_index(0);
}
}
@@ -413,7 +413,7 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p)
* us.
*/
if (prev_gsindex)
prev->gs = 0;
prev->gsbase = 0;
prev->gsindex = prev_gsindex;
switch_fpu_finish(next_fpu, fpu_switch);
@@ -536,7 +536,7 @@ long do_arch_prctl(struct task_struct *task, int code, unsigned long addr)
return -EPERM;
cpu = get_cpu();
task->thread.gsindex = 0;
task->thread.gs = addr;
task->thread.gsbase = addr;
if (doit) {
load_gs_index(0);
ret = wrmsrl_safe(MSR_KERNEL_GS_BASE, addr);
@@ -549,7 +549,7 @@ long do_arch_prctl(struct task_struct *task, int code, unsigned long addr)
return -EPERM;
cpu = get_cpu();
task->thread.fsindex = 0;
task->thread.fs = addr;
task->thread.fsbase = addr;
if (doit) {
/* set the selector to 0 to not confuse __switch_to */
loadsegment(fs, 0);
@@ -562,7 +562,7 @@ long do_arch_prctl(struct task_struct *task, int code, unsigned long addr)
if (doit)
rdmsrl(MSR_FS_BASE, base);
else
base = task->thread.fs;
base = task->thread.fsbase;
ret = put_user(base, (unsigned long __user *)addr);
break;
}
@@ -571,7 +571,7 @@ long do_arch_prctl(struct task_struct *task, int code, unsigned long addr)
if (doit)
rdmsrl(MSR_KERNEL_GS_BASE, base);
else
base = task->thread.gs;
base = task->thread.gsbase;
ret = put_user(base, (unsigned long __user *)addr);
break;
}