x86/compat: Move copy_siginfo_*_user32() to signal_compat.c

copy_siginfo_to_user32() and copy_siginfo_from_user32() are used
by both the 32-bit compat and x32 ABIs.  Move them to
signal_compat.c.

Signed-off-by: Brian Gerst <brgerst@gmail.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
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/1434974121-32575-2-git-send-email-brgerst@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

arch/x86/ia32/ia32_signal.c

@@ -34,99 +34,6 @@
 #include <asm/sys_ia32.h>
 #include <asm/smap.h>
 
-int copy_siginfo_to_user32(compat_siginfo_t __user *to, const siginfo_t *from)
-{
-	int err = 0;
-	bool ia32 = test_thread_flag(TIF_IA32);
-
-	if (!access_ok(VERIFY_WRITE, to, sizeof(compat_siginfo_t)))
-		return -EFAULT;
-
-	put_user_try {
-		/* If you change siginfo_t structure, please make sure that
-		   this code is fixed accordingly.
-		   It should never copy any pad contained in the structure
-		   to avoid security leaks, but must copy the generic
-		   3 ints plus the relevant union member.  */
-		put_user_ex(from->si_signo, &to->si_signo);
-		put_user_ex(from->si_errno, &to->si_errno);
-		put_user_ex((short)from->si_code, &to->si_code);
-
-		if (from->si_code < 0) {
-			put_user_ex(from->si_pid, &to->si_pid);
-			put_user_ex(from->si_uid, &to->si_uid);
-			put_user_ex(ptr_to_compat(from->si_ptr), &to->si_ptr);
-		} else {
-			/*
-			 * First 32bits of unions are always present:
-			 * si_pid === si_band === si_tid === si_addr(LS half)
-			 */
-			put_user_ex(from->_sifields._pad[0],
-					  &to->_sifields._pad[0]);
-			switch (from->si_code >> 16) {
-			case __SI_FAULT >> 16:
-				break;
-			case __SI_SYS >> 16:
-				put_user_ex(from->si_syscall, &to->si_syscall);
-				put_user_ex(from->si_arch, &to->si_arch);
-				break;
-			case __SI_CHLD >> 16:
-				if (ia32) {
-					put_user_ex(from->si_utime, &to->si_utime);
-					put_user_ex(from->si_stime, &to->si_stime);
-				} else {
-					put_user_ex(from->si_utime, &to->_sifields._sigchld_x32._utime);
-					put_user_ex(from->si_stime, &to->_sifields._sigchld_x32._stime);
-				}
-				put_user_ex(from->si_status, &to->si_status);
-				/* FALL THROUGH */
-			default:
-			case __SI_KILL >> 16:
-				put_user_ex(from->si_uid, &to->si_uid);
-				break;
-			case __SI_POLL >> 16:
-				put_user_ex(from->si_fd, &to->si_fd);
-				break;
-			case __SI_TIMER >> 16:
-				put_user_ex(from->si_overrun, &to->si_overrun);
-				put_user_ex(ptr_to_compat(from->si_ptr),
-					    &to->si_ptr);
-				break;
-				 /* This is not generated by the kernel as of now.  */
-			case __SI_RT >> 16:
-			case __SI_MESGQ >> 16:
-				put_user_ex(from->si_uid, &to->si_uid);
-				put_user_ex(from->si_int, &to->si_int);
-				break;
-			}
-		}
-	} put_user_catch(err);
-
-	return err;
-}
-
-int copy_siginfo_from_user32(siginfo_t *to, compat_siginfo_t __user *from)
-{
-	int err = 0;
-	u32 ptr32;
-
-	if (!access_ok(VERIFY_READ, from, sizeof(compat_siginfo_t)))
-		return -EFAULT;
-
-	get_user_try {
-		get_user_ex(to->si_signo, &from->si_signo);
-		get_user_ex(to->si_errno, &from->si_errno);
-		get_user_ex(to->si_code, &from->si_code);
-
-		get_user_ex(to->si_pid, &from->si_pid);
-		get_user_ex(to->si_uid, &from->si_uid);
-		get_user_ex(ptr32, &from->si_ptr);
-		to->si_ptr = compat_ptr(ptr32);
-	} get_user_catch(err);
-
-	return err;
-}
-
 /*
  * Do a signal return; undo the signal stack.
  */

arch/x86/kernel/Makefile

@@ -23,6 +23,7 @@ KASAN_SANITIZE_dumpstack_$(BITS).o := n
 CFLAGS_irq.o := -I$(src)/../include/asm/trace
 
 obj-y			:= process_$(BITS).o signal.o
+obj-$(CONFIG_COMPAT)	+= signal_compat.o
 obj-y			+= traps.o irq.o irq_$(BITS).o dumpstack_$(BITS).o
 obj-y			+= time.o ioport.o ldt.o dumpstack.o nmi.o
 obj-y			+= setup.o x86_init.o i8259.o irqinit.o jump_label.o

arch/x86/kernel/signal_compat.c

@@ -0,0 +1,95 @@
+#include <linux/compat.h>
+#include <linux/uaccess.h>
+
+int copy_siginfo_to_user32(compat_siginfo_t __user *to, const siginfo_t *from)
+{
+	int err = 0;
+	bool ia32 = test_thread_flag(TIF_IA32);
+
+	if (!access_ok(VERIFY_WRITE, to, sizeof(compat_siginfo_t)))
+		return -EFAULT;
+
+	put_user_try {
+		/* If you change siginfo_t structure, please make sure that
+		   this code is fixed accordingly.
+		   It should never copy any pad contained in the structure
+		   to avoid security leaks, but must copy the generic
+		   3 ints plus the relevant union member.  */
+		put_user_ex(from->si_signo, &to->si_signo);
+		put_user_ex(from->si_errno, &to->si_errno);
+		put_user_ex((short)from->si_code, &to->si_code);
+
+		if (from->si_code < 0) {
+			put_user_ex(from->si_pid, &to->si_pid);
+			put_user_ex(from->si_uid, &to->si_uid);
+			put_user_ex(ptr_to_compat(from->si_ptr), &to->si_ptr);
+		} else {
+			/*
+			 * First 32bits of unions are always present:
+			 * si_pid === si_band === si_tid === si_addr(LS half)
+			 */
+			put_user_ex(from->_sifields._pad[0],
+					  &to->_sifields._pad[0]);
+			switch (from->si_code >> 16) {
+			case __SI_FAULT >> 16:
+				break;
+			case __SI_SYS >> 16:
+				put_user_ex(from->si_syscall, &to->si_syscall);
+				put_user_ex(from->si_arch, &to->si_arch);
+				break;
+			case __SI_CHLD >> 16:
+				if (ia32) {
+					put_user_ex(from->si_utime, &to->si_utime);
+					put_user_ex(from->si_stime, &to->si_stime);
+				} else {
+					put_user_ex(from->si_utime, &to->_sifields._sigchld_x32._utime);
+					put_user_ex(from->si_stime, &to->_sifields._sigchld_x32._stime);
+				}
+				put_user_ex(from->si_status, &to->si_status);
+				/* FALL THROUGH */
+			default:
+			case __SI_KILL >> 16:
+				put_user_ex(from->si_uid, &to->si_uid);
+				break;
+			case __SI_POLL >> 16:
+				put_user_ex(from->si_fd, &to->si_fd);
+				break;
+			case __SI_TIMER >> 16:
+				put_user_ex(from->si_overrun, &to->si_overrun);
+				put_user_ex(ptr_to_compat(from->si_ptr),
+					    &to->si_ptr);
+				break;
+				 /* This is not generated by the kernel as of now.  */
+			case __SI_RT >> 16:
+			case __SI_MESGQ >> 16:
+				put_user_ex(from->si_uid, &to->si_uid);
+				put_user_ex(from->si_int, &to->si_int);
+				break;
+			}
+		}
+	} put_user_catch(err);
+
+	return err;
+}
+
+int copy_siginfo_from_user32(siginfo_t *to, compat_siginfo_t __user *from)
+{
+	int err = 0;
+	u32 ptr32;
+
+	if (!access_ok(VERIFY_READ, from, sizeof(compat_siginfo_t)))
+		return -EFAULT;
+
+	get_user_try {
+		get_user_ex(to->si_signo, &from->si_signo);
+		get_user_ex(to->si_errno, &from->si_errno);
+		get_user_ex(to->si_code, &from->si_code);
+
+		get_user_ex(to->si_pid, &from->si_pid);
+		get_user_ex(to->si_uid, &from->si_uid);
+		get_user_ex(ptr32, &from->si_ptr);
+		to->si_ptr = compat_ptr(ptr32);
+	} get_user_catch(err);
+
+	return err;
+}