x86/entry: Rename is_{ia32,x32}_task() to in_{ia32,x32}_syscall()

The is_ia32_task()/is_x32_task() function names are a big misnomer: they
suggests that the compat-ness of a system call is a task property, which
is not true, the compatness of a system call purely depends on how it
was invoked through the system call layer.

A task may call 32-bit and 64-bit and x32 system calls without changing
any of its kernel visible state.

This specific minomer is also actively dangerous, as it might cause kernel
developers to use the wrong kind of security checks within system calls.

So rename it to in_{ia32,x32}_syscall().

Suggested-by: Andy Lutomirski <luto@amacapital.net>
Suggested-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Dmitry Safonov <dsafonov@virtuozzo.com>
[ Expanded the changelog. ]
Acked-by: Andy Lutomirski <luto@kernel.org>
Cc: 0x7f454c46@gmail.com
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>
Cc: akpm@linux-foundation.org
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/1460987025-30360-1-git-send-email-dsafonov@virtuozzo.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

2 files changed, 3 insertions, 3 deletions

diff --git a/arch/x86/include/asm/compat.h b/arch/x86/include/asm/compat.h
index ebb102e1bbc7a..5a3b2c119ed0e 100644
--- a/arch/x86/include/asm/compat.h
+++ b/arch/x86/include/asm/compat.h
@@ -307,7 +307,7 @@ static inline void __user *arch_compat_alloc_user_space(long len)
 	return (void __user *)round_down(sp - len, 16);
 }
 
-static inline bool is_x32_task(void)
+static inline bool in_x32_syscall(void)
 {
 #ifdef CONFIG_X86_X32_ABI
 	if (task_pt_regs(current)->orig_ax & __X32_SYSCALL_BIT)
@@ -318,7 +318,7 @@ static inline bool is_x32_task(void)
 
 static inline bool in_compat_syscall(void)
 {
-	return is_ia32_task() || is_x32_task();
+	return in_ia32_syscall() || in_x32_syscall();
 }
 #define in_compat_syscall in_compat_syscall	/* override the generic impl */
 
diff --git a/arch/x86/include/asm/thread_info.h b/arch/x86/include/asm/thread_info.h
index ffae84df8a931..30c133ac05cd8 100644
--- a/arch/x86/include/asm/thread_info.h
+++ b/arch/x86/include/asm/thread_info.h
@@ -255,7 +255,7 @@ static inline bool test_and_clear_restore_sigmask(void)
 	return true;
 }
 
-static inline bool is_ia32_task(void)
+static inline bool in_ia32_syscall(void)
 {
 #ifdef CONFIG_X86_32
 	return true;