[PATCH] x86_64: Implement is_compat_task the right way

By setting a flag during a 32bit system call only

Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

6 files changed, 16 insertions, 1 deletions

diff --git a/arch/x86_64/ia32/ia32entry.S b/arch/x86_64/ia32/ia32entry.S
index 8172e61c3f6f..58f5bfb52c63 100644
--- a/arch/x86_64/ia32/ia32entry.S
+++ b/arch/x86_64/ia32/ia32entry.S
@@ -104,6 +104,7 @@ ENTRY(ia32_sysenter_target)
         .quad 1b,ia32_badarg
         .previous       
         GET_THREAD_INFO(%r10)
+        orl    $TS_COMPAT,threadinfo_status(%r10)
         testl  $(_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT|_TIF_SECCOMP),threadinfo_flags(%r10)
         CFI_REMEMBER_STATE
         jnz  sysenter_tracesys
@@ -117,6 +118,7 @@ sysenter_do_call:
         cli
         testl   $_TIF_ALLWORK_MASK,threadinfo_flags(%r10)
         jnz     int_ret_from_sys_call
+        andl    $~TS_COMPAT,threadinfo_status(%r10)
         /* clear IF, that popfq doesn't enable interrupts early */
         andl  $~0x200,EFLAGS-R11(%rsp) 
         RESTORE_ARGS 1,24,1,1,1,1
@@ -203,6 +205,7 @@ ENTRY(ia32_cstar_target)
         .quad 1b,ia32_badarg
         .previous       
         GET_THREAD_INFO(%r10)
+        orl   $TS_COMPAT,threadinfo_status(%r10)
         testl $(_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT|_TIF_SECCOMP),threadinfo_flags(%r10)
         CFI_REMEMBER_STATE
         jnz   cstar_tracesys
@@ -216,6 +219,7 @@ cstar_do_call:
         cli
         testl $_TIF_ALLWORK_MASK,threadinfo_flags(%r10)
         jnz  int_ret_from_sys_call
+        andl $~TS_COMPAT,threadinfo_status(%r10)
         RESTORE_ARGS 1,-ARG_SKIP,1,1,1
         movl RIP-ARGOFFSET(%rsp),%ecx
         CFI_REGISTER rip,rcx
@@ -288,6 +292,7 @@ ENTRY(ia32_syscall)
            this could be a problem. */
         SAVE_ARGS 0,0,1
         GET_THREAD_INFO(%r10)
+        orl   $TS_COMPAT,threadinfo_status(%r10)
         testl $(_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT|_TIF_SECCOMP),threadinfo_flags(%r10)
         jnz ia32_tracesys
 ia32_do_syscall:        
diff --git a/arch/x86_64/kernel/asm-offsets.c b/arch/x86_64/kernel/asm-offsets.c
index 00a08d13230a..cfb4f9cebea4 100644
--- a/arch/x86_64/kernel/asm-offsets.c
+++ b/arch/x86_64/kernel/asm-offsets.c
@@ -33,6 +33,7 @@ int main(void)
         ENTRY(flags);
         ENTRY(addr_limit);
         ENTRY(preempt_count);
+        ENTRY(status);
         BLANK();
 #undef ENTRY
 #define ENTRY(entry) DEFINE(pda_ ## entry, offsetof(struct x8664_pda, entry))
diff --git a/arch/x86_64/kernel/entry.S b/arch/x86_64/kernel/entry.S
index 45e0ab8a1fca..300555bc56b3 100644
--- a/arch/x86_64/kernel/entry.S
+++ b/arch/x86_64/kernel/entry.S
@@ -313,6 +313,7 @@ int_with_check:
         movl threadinfo_flags(%rcx),%edx
         andl %edi,%edx
         jnz   int_careful
+        andl    $~TS_COMPAT,threadinfo_status(%rcx)
         jmp   retint_swapgs
 
         /* Either reschedule or signal or syscall exit tracking needed. */
diff --git a/drivers/input/evdev.c b/drivers/input/evdev.c
index f7490a015d18..362b33556b1a 100644
--- a/drivers/input/evdev.c
+++ b/drivers/input/evdev.c
@@ -154,8 +154,10 @@ struct input_event_compat {
         __s32 value;
 };
 
+/* Note to the author of this code: did it ever occur to
+   you why the ifdefs are needed? Think about it again. -AK */
 #ifdef CONFIG_X86_64
-#  define COMPAT_TEST test_thread_flag(TIF_IA32)
+#  define COMPAT_TEST is_compat_task()
 #elif defined(CONFIG_IA64)
 #  define COMPAT_TEST IS_IA32_PROCESS(ia64_task_regs(current))
 #elif defined(CONFIG_S390)
diff --git a/include/asm-x86_64/compat.h b/include/asm-x86_64/compat.h
index f0155c38f639..3863a7da372b 100644
--- a/include/asm-x86_64/compat.h
+++ b/include/asm-x86_64/compat.h
@@ -202,4 +202,9 @@ static __inline__ void __user *compat_alloc_user_space(long len)
         return (void __user *)regs->rsp - len; 
 }
 
+static inline int is_compat_task(void)
+{
+        return current_thread_info()->status & TS_COMPAT;
+}
+
 #endif /* _ASM_X86_64_COMPAT_H */
diff --git a/include/asm-x86_64/thread_info.h b/include/asm-x86_64/thread_info.h
index 08eb6e4f3737..eb7c5fda1870 100644
--- a/include/asm-x86_64/thread_info.h
+++ b/include/asm-x86_64/thread_info.h
@@ -138,6 +138,7 @@ static inline struct thread_info *stack_thread_info(void)
  * have to worry about atomic accesses.
  */
 #define TS_USEDFPU              0x0001  /* FPU was used by this task this quantum (SMP) */
+#define TS_COMPAT               0x0002  /* 32bit syscall active */
 
 #endif /* __KERNEL__ */