microblaze: Implement include/asm/syscall.h.

Signed-off-by: Edgar E. Iglesias <edgar.iglesias@gmail.com>
Signed-off-by: Michal Simek <monstr@monstr.eu>

arch/microblaze/include/asm/syscall.h

+#ifndef __ASM_MICROBLAZE_SYSCALL_H
+#define __ASM_MICROBLAZE_SYSCALL_H
+
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <asm/ptrace.h>
+
+/* The system call number is given by the user in R12 */
+static inline long syscall_get_nr(struct task_struct *task,
+				  struct pt_regs *regs)
+{
+	return regs->r12;
+}
+
+static inline void syscall_rollback(struct task_struct *task,
+				    struct pt_regs *regs)
+{
+	/* TODO.  */
+}
+
+static inline long syscall_get_error(struct task_struct *task,
+				     struct pt_regs *regs)
+{
+	return IS_ERR_VALUE(regs->r3) ? regs->r3 : 0;
+}
+
+static inline long syscall_get_return_value(struct task_struct *task,
+					    struct pt_regs *regs)
+{
+	return regs->r3;
+}
+
+static inline void syscall_set_return_value(struct task_struct *task,
+					    struct pt_regs *regs,
+					    int error, long val)
+{
+	if (error)
+		regs->r3 = -error;
+	else
+		regs->r3 = val;
+}
+
+static inline microblaze_reg_t microblaze_get_syscall_arg(struct pt_regs *regs,
+							  unsigned int n)
+{
+	switch (n) {
+	case 5: return regs->r10;
+	case 4: return regs->r9;
+	case 3: return regs->r8;
+	case 2: return regs->r7;
+	case 1: return regs->r6;
+	case 0: return regs->r5;
+	default:
+		BUG();
+	}
+	return ~0;
+}
+
+static inline void microblaze_set_syscall_arg(struct pt_regs *regs,
+					      unsigned int n,
+					      unsigned long val)
+{
+	switch (n) {
+	case 5:
+		regs->r10 = val;
+	case 4:
+		regs->r9 = val;
+	case 3:
+		regs->r8 = val;
+	case 2:
+		regs->r7 = val;
+	case 1:
+		regs->r6 = val;
+	case 0:
+		regs->r5 = val;
+	default:
+		BUG();
+	}
+}
+
+static inline void syscall_get_arguments(struct task_struct *task,
+					 struct pt_regs *regs,
+					 unsigned int i, unsigned int n,
+					 unsigned long *args)
+{
+	while (n--)
+		*args++ = microblaze_get_syscall_arg(regs, i++);
+}
+
+static inline void syscall_set_arguments(struct task_struct *task,
+					 struct pt_regs *regs,
+					 unsigned int i, unsigned int n,
+					 const unsigned long *args)
+{
+	while (n--)
+		microblaze_set_syscall_arg(regs, i++, *args++);
+}
+
+#endif /* __ASM_MICROBLAZE_SYSCALL_H */