BACKPORT: x86/syscalls: Move compat syscall entry handling into syscalltbl.sh

Rather than duplicating the compat entry handling in all
consumers of syscalls_BITS.h, handle it directly in
syscalltbl.sh.  Now we generate entries in syscalls_32.h like:

__SYSCALL_I386(5, sys_open)
__SYSCALL_I386(5, compat_sys_open)

and all of its consumers implicitly get the right entry point.

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: Frederic Weisbecker <fweisbec@gmail.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/b7c2b501dc0e6e43050e916b95807c3e2e16e9bb.1454022279.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
(cherry picked from commit 3e65654e3db6df6aba9c5b895f8b8e6a8d8eb508)

Bug: 119769499
Change-Id: Iacf7ca64ca633dcba9c501017fbfed8af8623c93
[ghackmann@google.com: track down all the relevant __SYSCALL_* macros,
 which have moved around a lot after 3.18]
Signed-off-by: Greg Hackmann <ghackmann@google.com>

9 files changed, 33 insertions, 19 deletions

diff --git a/arch/x86/ia32/syscall_ia32.c b/arch/x86/ia32/syscall_ia32.c
index 4754ba0f5d9f..87ef508db4c7 100644
--- a/arch/x86/ia32/syscall_ia32.c
+++ b/arch/x86/ia32/syscall_ia32.c
@@ -5,11 +5,11 @@
 #include <linux/cache.h>
 #include <asm/asm-offsets.h>
 
-#define __SYSCALL_I386(nr, sym, compat) extern asmlinkage void compat(void) ;
+#define __SYSCALL_I386(nr, sym) extern asmlinkage void sym(void) ;
 #include <asm/syscalls_32.h>
 #undef __SYSCALL_I386
 
-#define __SYSCALL_I386(nr, sym, compat) [nr] = compat,
+#define __SYSCALL_I386(nr, sym) [nr] = sym,
 
 typedef void (*sys_call_ptr_t)(void);
 
diff --git a/arch/x86/kernel/asm-offsets_32.c b/arch/x86/kernel/asm-offsets_32.c
index d67c4be3e8b1..e5734ab91959 100644
--- a/arch/x86/kernel/asm-offsets_32.c
+++ b/arch/x86/kernel/asm-offsets_32.c
@@ -3,7 +3,7 @@
 #include <linux/lguest.h>
 #include "../../../drivers/lguest/lg.h"
 
-#define __SYSCALL_I386(nr, sym, compat) [nr] = 1,
+#define __SYSCALL_I386(nr, sym) [nr] = 1,
 static char syscalls[] = {
 #include <asm/syscalls_32.h>
 };
diff --git a/arch/x86/kernel/asm-offsets_64.c b/arch/x86/kernel/asm-offsets_64.c
index 72a262a496ae..e2a958f92e84 100644
--- a/arch/x86/kernel/asm-offsets_64.c
+++ b/arch/x86/kernel/asm-offsets_64.c
@@ -1,10 +1,10 @@
 #include <asm/ia32.h>
 
-#define __SYSCALL_64(nr, sym, compat) [nr] = 1,
+#define __SYSCALL_64(nr, sym) [nr] = 1,
 static char syscalls_64[] = {
 #include <asm/syscalls_64.h>
 };
-#define __SYSCALL_I386(nr, sym, compat) [nr] = 1,
+#define __SYSCALL_I386(nr, sym) [nr] = 1,
 static char syscalls_ia32[] = {
 #include <asm/syscalls_32.h>
 };
diff --git a/arch/x86/kernel/syscall_32.c b/arch/x86/kernel/syscall_32.c
index e9bcd57d8a9e..340816121f11 100644
--- a/arch/x86/kernel/syscall_32.c
+++ b/arch/x86/kernel/syscall_32.c
@@ -5,11 +5,11 @@
 #include <linux/cache.h>
 #include <asm/asm-offsets.h>
 
-#define __SYSCALL_I386(nr, sym, compat) extern asmlinkage void sym(void) ;
+#define __SYSCALL_I386(nr, sym) extern asmlinkage void sym(void) ;
 #include <asm/syscalls_32.h>
 #undef __SYSCALL_I386
 
-#define __SYSCALL_I386(nr, sym, compat) [nr] = sym,
+#define __SYSCALL_I386(nr, sym) [nr] = sym,
 
 typedef asmlinkage void (*sys_call_ptr_t)(void);
 
diff --git a/arch/x86/kernel/syscall_64.c b/arch/x86/kernel/syscall_64.c
index 9ed5128f975f..a511358a11bd 100644
--- a/arch/x86/kernel/syscall_64.c
+++ b/arch/x86/kernel/syscall_64.c
@@ -6,11 +6,11 @@
 #include <asm/asm-offsets.h>
 #include <asm/syscall.h>
 
-#define __SYSCALL_64(nr, sym, compat) extern asmlinkage void sym(void) ;
+#define __SYSCALL_64(nr, sym) extern asmlinkage void sym(void) ;
 #include <asm/syscalls_64.h>
 #undef __SYSCALL_64
 
-#define __SYSCALL_64(nr, sym, compat) [nr] = sym,
+#define __SYSCALL_64(nr, sym) [nr] = sym,
 
 extern void sys_ni_syscall(void);
 
diff --git a/arch/x86/syscalls/syscalltbl.sh b/arch/x86/syscalls/syscalltbl.sh
index 5ebeaf1041e7..b81479c8c5fb 100644
--- a/arch/x86/syscalls/syscalltbl.sh
+++ b/arch/x86/syscalls/syscalltbl.sh
@@ -8,10 +8,24 @@ emit() {
     nr="$2"
     entry="$3"
     compat="$4"
-    if [ -n "$compat" ]; then
-	echo "__SYSCALL_${abi}($nr, $entry, $compat)"
-    elif [ -n "$entry" ]; then
-	echo "__SYSCALL_${abi}($nr, $entry, $entry)"
+
+    if [ "$abi" == "64" -a -n "$compat" ]; then
+	echo "a compat entry for a 64-bit syscall makes no sense" >&2
+	exit 1
+    fi
+
+    if [ -z "$compat" ]; then
+	if [ -n "$entry" ]; then
+	    echo "__SYSCALL_${abi}($nr, $entry)"
+	fi
+    else
+	echo "#ifdef CONFIG_X86_32"
+	if [ -n "$entry" ]; then
+	    echo "__SYSCALL_${abi}($nr, $entry)"
+	fi
+	echo "#else"
+	echo "__SYSCALL_${abi}($nr, $compat)"
+	echo "#endif"
     fi
 }
 
diff --git a/arch/x86/um/sys_call_table_32.c b/arch/x86/um/sys_call_table_32.c
index 531d4269e2e3..faece1e4c38e 100644
--- a/arch/x86/um/sys_call_table_32.c
+++ b/arch/x86/um/sys_call_table_32.c
@@ -24,11 +24,11 @@
 
 #define old_mmap sys_old_mmap
 
-#define __SYSCALL_I386(nr, sym, compat) extern asmlinkage void sym(void) ;
+#define __SYSCALL_I386(nr, sym) extern asmlinkage void sym(void) ;
 #include <asm/syscalls_32.h>
 
 #undef __SYSCALL_I386
-#define __SYSCALL_I386(nr, sym, compat) [ nr ] = sym,
+#define __SYSCALL_I386(nr, sym) [ nr ] = sym,
 
 typedef asmlinkage void (*sys_call_ptr_t)(void);
 
diff --git a/arch/x86/um/sys_call_table_64.c b/arch/x86/um/sys_call_table_64.c
index 0b20807582fc..1b67544307cd 100644
--- a/arch/x86/um/sys_call_table_64.c
+++ b/arch/x86/um/sys_call_table_64.c
@@ -33,11 +33,11 @@
 #define stub_execve sys_execve
 #define stub_rt_sigreturn sys_rt_sigreturn
 
-#define __SYSCALL_64(nr, sym, compat) extern asmlinkage void sym(void) ;
+#define __SYSCALL_64(nr, sym) extern asmlinkage void sym(void) ;
 #include <asm/syscalls_64.h>
 
 #undef __SYSCALL_64
-#define __SYSCALL_64(nr, sym, compat) [ nr ] = sym,
+#define __SYSCALL_64(nr, sym) [ nr ] = sym,
 
 typedef void (*sys_call_ptr_t)(void);
 
diff --git a/arch/x86/um/user-offsets.c b/arch/x86/um/user-offsets.c
index 5edf4f4bbf53..6c9a9c1eae32 100644
--- a/arch/x86/um/user-offsets.c
+++ b/arch/x86/um/user-offsets.c
@@ -9,12 +9,12 @@
 #include <asm/types.h>
 
 #ifdef __i386__
-#define __SYSCALL_I386(nr, sym, compat) [nr] = 1,
+#define __SYSCALL_I386(nr, sym) [nr] = 1,
 static char syscalls[] = {
 #include <asm/syscalls_32.h>
 };
 #else
-#define __SYSCALL_64(nr, sym, compat) [nr] = 1,
+#define __SYSCALL_64(nr, sym) [nr] = 1,
 static char syscalls[] = {
 #include <asm/syscalls_64.h>
 };