[PATCH v2 15/29] nios2: System calls handling

Ley Foon Tan
2014-07-15T08:51:36Z

This patch adds support for system calls from userspaces. It uses the
asm-generic/unistd.h definitions with architecture spcific syscall. The sys_call_table
is just an array defined in a C file and it contains pointers to the syscall functions.

Signed-off-by: Ley Foon Tan <lftan@altera.com>
---
arch/nios2/include/asm/syscall.h | 138 +++++++++++++++++++++++++++++++++++
arch/nios2/include/asm/syscalls.h | 25 +++++++
arch/nios2/include/uapi/asm/unistd.h | 25 +++++++
arch/nios2/kernel/sys_nios2.c | 66 +++++++++++++++++
arch/nios2/kernel/syscall_table.c | 29 ++++++++
5 files changed, 283 insertions(+)
create mode 100644 arch/nios2/include/asm/syscall.h
create mode 100644 arch/nios2/include/asm/syscalls.h
create mode 100644 arch/nios2/include/uapi/asm/unistd.h
create mode 100644 arch/nios2/kernel/sys_nios2.c
create mode 100644 arch/nios2/kernel/syscall_table.c

diff --git a/arch/nios2/include/asm/syscall.h b/arch/nios2/include/asm/syscall.h
new file mode 100644
index 0000000..9de2208
--- /dev/null
+++ b/arch/nios2/include/asm/syscall.h
@@ -0,0 +1,138 @@
+/*
+ * Copyright Altera Corporation (C) <2014>. All rights reserved
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope 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_NIOS2_SYSCALL_H__
+#define __ASM_NIOS2_SYSCALL_H__
+
+#include <linux/err.h>
+#include <linux/sched.h>
+
+static inline int syscall_get_nr(struct task_struct *task, struct pt_regs *regs)
+{
+ return regs->r2;
+}
+
+static inline void syscall_rollback(struct task_struct *task,
+ struct pt_regs *regs)
+{
+ regs->r2 = regs->orig_r2;
+ regs->r7 = regs->orig_r7;
+}
+
+static inline long syscall_get_error(struct task_struct *task,
+ struct pt_regs *regs)
+{
+ return regs->r7 ? regs->r2 : 0;
+}
+
+static inline long syscall_get_return_value(struct task_struct *task,
+ struct pt_regs *regs)
+{
+ return regs->r2;
+}
+
+static inline void syscall_set_return_value(struct task_struct *task,
+ struct pt_regs *regs, int error, long val)
+{
+ if (error) {
+ /* error < 0, but nios2 uses > 0 return value */
+ regs->r2 = -error;
+ regs->r7 = 1;
+ } else {
+ regs->r2 = val;
+ regs->r7 = 0;
+ }
+}
+
+static inline void syscall_get_arguments(struct task_struct *task,
+ struct pt_regs *regs, unsigned int i, unsigned int n,
+ unsigned long *args)
+{
+ BUG_ON(i + n > 6);
+
+ switch (i) {
+ case 0:
+ if (!n--)
+ break;
+ *args++ = regs->r4;
+ case 1:
+ if (!n--)
+ break;
+ *args++ = regs->r5;
+ case 2:
+ if (!n--)
+ break;
+ *args++ = regs->r6;
+ case 3:
+ if (!n--)
+ break;
+ *args++ = regs->r7;
+ case 4:
+ if (!n--)
+ break;
+ *args++ = regs->r8;
+ case 5:
+ if (!n--)
+ break;
+ *args++ = regs->r9;
+ case 6:
+ if (!n--)
+ break;
+ default:
+ BUG();
+ }
+}
+
+static inline void syscall_set_arguments(struct task_struct *task,
+ struct pt_regs *regs, unsigned int i, unsigned int n,
+ const unsigned long *args)
+{
+ BUG_ON(i + n > 6);
+
+ switch (i) {
+ case 0:
+ if (!n--)
+ break;
+ regs->r4 = *args++;
+ case 1:
+ if (!n--)
+ break;
+ regs->r5 = *args++;
+ case 2:
+ if (!n--)
+ break;
+ regs->r6 = *args++;
+ case 3:
+ if (!n--)
+ break;
+ regs->r7 = *args++;
+ case 4:
+ if (!n--)
+ break;
+ regs->r8 = *args++;
+ case 5:
+ if (!n--)
+ break;
+ regs->r9 = *args++;
+ case 6:
+ if (!n)
+ break;
+ default:
+ BUG();
+ }
+}
+
+#endif
diff --git a/arch/nios2/include/asm/syscalls.h b/arch/nios2/include/asm/syscalls.h
new file mode 100644
index 0000000..0245d78
--- /dev/null
+++ b/arch/nios2/include/asm/syscalls.h
@@ -0,0 +1,25 @@
+/*
+ * Copyright Altera Corporation (C) 2013. All rights reserved
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope 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_NIOS2_SYSCALLS_H
+#define __ASM_NIOS2_SYSCALLS_H
+
+int sys_cacheflush(unsigned long addr, unsigned long len,
+ unsigned int op);
+
+#include <asm-generic/syscalls.h>
+
+#endif /* __ASM_NIOS2_SYSCALLS_H */
diff --git a/arch/nios2/include/uapi/asm/unistd.h b/arch/nios2/include/uapi/asm/unistd.h
new file mode 100644
index 0000000..c4bf795
--- /dev/null
+++ b/arch/nios2/include/uapi/asm/unistd.h
@@ -0,0 +1,25 @@
+/*
+ * Copyright (C) 2013 Altera Corporation
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope 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/>.
+ *
+ */
+
+ #define sys_mmap2 sys_mmap_pgoff
+
+/* Use the standard ABI for syscalls */
+#include <asm-generic/unistd.h>
+
+/* Additional Nios II specific syscalls. */
+#define __NR_cacheflush (__NR_arch_specific_syscall)
+__SYSCALL(__NR_cacheflush, sys_cacheflush)
diff --git a/arch/nios2/kernel/sys_nios2.c b/arch/nios2/kernel/sys_nios2.c
new file mode 100644
index 0000000..b418f7e
--- /dev/null
+++ b/arch/nios2/kernel/sys_nios2.c
@@ -0,0 +1,66 @@
+/*
+ * Copyright (C) 2013 Altera Corporation
+ * Copyright (C) 2011-2012 Tobias Klauser <tklauser@distanz.ch>
+ * Copyright (C) 2004 Microtronix Datacom Ltd.
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License. See the file "COPYING" in the main directory of this archive
+ * for more details.
+ */
+
+#include <linux/export.h>
+#include <linux/file.h>
+#include <linux/fs.h>
+#include <linux/slab.h>
+#include <linux/syscalls.h>
+
+#include <asm/cacheflush.h>
+#include <asm/traps.h>
+
+/* sys_cacheflush -- flush the processor cache. */
+asmlinkage int sys_cacheflush(unsigned long addr, unsigned long len,
+ unsigned int op)
+{
+ struct vm_area_struct *vma;
+
+ if (len == 0)
+ return 0;
+
+ /* We only support op 0 now, return error if op is non-zero.*/
+ if (op)
+ return -EINVAL;
+
+ /* Check for overflow */
+ if (addr + len < addr)
+ return -EFAULT;
+
+ /*
+ * Verify that the specified address region actually belongs
+ * to this process.
+ */
+ vma = find_vma(current->mm, addr);
+ if (vma == NULL || addr < vma->vm_start || addr + len > vma->vm_end)
+ return -EFAULT;
+
+ flush_cache_range(vma, addr, addr + len);
+
+ return 0;
+}
+
+asmlinkage int sys_getpagesize(void)
+{
+ return PAGE_SIZE;
+}
+
+#if defined(CONFIG_FB) || defined(CONFIG_FB_MODULE)
+#include <linux/fb.h>
+unsigned long get_fb_unmapped_area(struct file *filp, unsigned long orig_addr,
+ unsigned long len, unsigned long pgoff, unsigned long flags)
+{
+
+ struct fb_info *info = filp->private_data;
+
+ return info->screen_base;
+}
+EXPORT_SYMBOL(get_fb_unmapped_area);
+#endif /* CONFIG_FB */
diff --git a/arch/nios2/kernel/syscall_table.c b/arch/nios2/kernel/syscall_table.c
new file mode 100644
index 0000000..06e6ac1
--- /dev/null
+++ b/arch/nios2/kernel/syscall_table.c
@@ -0,0 +1,29 @@
+/*
+ * Copyright Altera Corporation (C) 2013. All rights reserved
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope 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/>.
+ *
+ */
+
+#include <linux/syscalls.h>
+#include <linux/signal.h>
+#include <linux/unistd.h>
+
+#include <asm/syscalls.h>
+
+#undef __SYSCALL
+#define __SYSCALL(nr, call) [nr] = (call),
+
+void *sys_call_table[__NR_syscalls] = {
+#include <asm/unistd.h>
+};
--
1.8.2.1