arm64: System calls handling

This patch adds support for system calls coming from 64-bit
applications. It uses the asm-generic/unistd.h definitions with the
canonical set of system calls. The private system calls are only used
for 32-bit (compat) applications as 64-bit ones can set the TLS and
flush the caches entirely from user space.

The sys_call_table is just an array defined in a C file and it contains
pointers to the syscall functions. The array is 4KB aligned to allow the
use of the ADRP instruction (longer range ADR) in entry.S.

Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Tony Lindgren <tony@atomide.com>
Acked-by: Nicolas Pitre <nico@linaro.org>
Acked-by: Olof Johansson <olof@lixom.net>
Acked-by: Santosh Shilimkar <santosh.shilimkar@ti.com>

1 files changed, 40 insertions, 0 deletions

diff --git a/arch/arm64/include/asm/syscalls.h b/arch/arm64/include/asm/syscalls.h
new file mode 100644
index 0000000..09ff335
--- /dev/null
+++ b/arch/arm64/include/asm/syscalls.h
@@ -0,0 +1,40 @@
+/*
+ * Copyright (C) 2012 ARM Ltd.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+#ifndef __ASM_SYSCALLS_H
+#define __ASM_SYSCALLS_H
+
+#include <linux/linkage.h>
+#include <linux/compiler.h>
+#include <linux/signal.h>
+
+/*
+ * System call wrappers implemented in kernel/entry.S.
+ */
+asmlinkage long sys_execve_wrapper(const char __user *filename,
+				   const char __user *const __user *argv,
+				   const char __user *const __user *envp);
+asmlinkage long sys_clone_wrapper(unsigned long clone_flags,
+				  unsigned long newsp,
+				  void __user *parent_tid,
+				  unsigned long tls_val,
+				  void __user *child_tid);
+asmlinkage long sys_rt_sigreturn_wrapper(void);
+asmlinkage long sys_sigaltstack_wrapper(const stack_t __user *uss,
+					stack_t __user *uoss);
+
+#include <asm-generic/syscalls.h>
+
+#endif	/* __ASM_SYSCALLS_H */