[PATCH] uml: x86_64 thread fixes

x86_64 needs some TLS fixes.  What was missing was remembering the child
thread id during clone and stuffing it into the child during each context
switch.

The %fs value is stored separately in the thread structure since the host
controls what effect it has on the actual register file.  The host also needs
to store it in its own thread struct, so we need the value kept outside the
register file.

arch_prctl_skas was fixed to call PTRACE_ARCH_PRCTL appropriately.  There is
some saving and restoring of registers in the ARCH_SET_* cases so that the
correct set of registers are changed on the host and restored to the process
when it runs again.

Signed-off-by: Jeff Dike <jdike@addtoit.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

2 files changed, 6 insertions, 6 deletions

diff --git a/include/asm-um/processor-x86_64.h b/include/asm-um/processor-x86_64.h
index 10609af376c0..31c2d4d685bd 100644
--- a/include/asm-um/processor-x86_64.h
+++ b/include/asm-um/processor-x86_64.h
@@ -13,6 +13,7 @@
 struct arch_thread {
         unsigned long debugregs[8];
         int debugregs_seq;
+        unsigned long fs;
         struct faultinfo faultinfo;
 };
 
@@ -25,8 +26,9 @@ extern inline void rep_nop(void)
 #define cpu_relax()   rep_nop()
 
 #define INIT_ARCH_THREAD { .debugregs           = { [ 0 ... 7 ] = 0 }, \
-                           .debugregs_seq       = 0, \
-                           .faultinfo           = { 0, 0, 0 } }
+                           .debugregs_seq       = 0,                           \
+                           .fs                  = 0, \
+                           .faultinfo           = { 0, 0, 0 } }
 
 static inline void arch_flush_thread(struct arch_thread *thread)
 {
diff --git a/include/asm-um/ptrace-x86_64.h b/include/asm-um/ptrace-x86_64.h
index 03b4af4ac09a..a927450ce401 100644
--- a/include/asm-um/ptrace-x86_64.h
+++ b/include/asm-um/ptrace-x86_64.h
@@ -81,9 +81,7 @@ static inline void arch_switch_to_tt(struct task_struct *from,
 {
 }
 
-static inline void arch_switch_to_skas(struct task_struct *from,
-                                       struct task_struct *to)
-{
-}
+extern void arch_switch_to_skas(struct task_struct *from,
+                                struct task_struct *to);
 
 #endif