sh: Provide the asm/syscall.h interface, needed by tracehook.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>

arch/sh/include/asm/syscall.h

+#ifndef __ASM_SH_SYSCALL_H
+#define __ASM_SH_SYSCALL_H
+
+#ifdef CONFIG_SUPERH32
+# include "syscall_32.h"
+#else
+# include "syscall_64.h"
+#endif
+
+#endif /* __ASM_SH_SYSCALL_H */

arch/sh/include/asm/syscall_32.h

+#ifndef __ASM_SH_SYSCALL_32_H
+#define __ASM_SH_SYSCALL_32_H
+
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <asm/ptrace.h>
+
+/* The system call number is given by the user in %g1 */
+static inline long syscall_get_nr(struct task_struct *task,
+				  struct pt_regs *regs)
+{
+	return (regs->tra >= 0) ? regs->regs[3] : -1L;
+}
+
+static inline void syscall_rollback(struct task_struct *task,
+				    struct pt_regs *regs)
+{
+	/*
+	 * XXX: This needs some thought. On SH we don't
+	 * save away the original r0 value anywhere.
+	 */
+}
+
+static inline bool syscall_has_error(struct pt_regs *regs)
+{
+	return (regs->sr & 0x1) ? true : false;
+}
+static inline void syscall_set_error(struct pt_regs *regs)
+{
+	regs->sr |= 0x1;
+}
+static inline void syscall_clear_error(struct pt_regs *regs)
+{
+	regs->sr &= ~0x1;
+}
+
+static inline long syscall_get_error(struct task_struct *task,
+				     struct pt_regs *regs)
+{
+	return syscall_has_error(regs) ? regs->regs[0] : 0;
+}
+
+static inline long syscall_get_return_value(struct task_struct *task,
+					    struct pt_regs *regs)
+{
+	return regs->regs[0];
+}
+
+static inline void syscall_set_return_value(struct task_struct *task,
+					    struct pt_regs *regs,
+					    int error, long val)
+{
+	if (error) {
+		syscall_set_error(regs);
+		regs->regs[0] = -error;
+	} else {
+		syscall_clear_error(regs);
+		regs->regs[0] = val;
+	}
+}
+
+static inline void syscall_get_arguments(struct task_struct *task,
+					 struct pt_regs *regs,
+					 unsigned int i, unsigned int n,
+					 unsigned long *args)
+{
+	/*
+	 * Do this simply for now. If we need to start supporting
+	 * fetching arguments from arbitrary indices, this will need some
+	 * extra logic. Presently there are no in-tree users that depend
+	 * on this behaviour.
+	 */
+	BUG_ON(i);
+
+	/* Argument pattern is: R4, R5, R6, R7, R0, R1 */
+	switch (n) {
+	case 6: args[5] = regs->regs[1];
+	case 5: args[4] = regs->regs[0];
+	case 4: args[3] = regs->regs[7];
+	case 3: args[2] = regs->regs[6];
+	case 2: args[1] = regs->regs[5];
+	case 1:	args[0] = regs->regs[4];
+		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)
+{
+	/* Same note as above applies */
+	BUG_ON(i);
+
+	switch (n) {
+	case 6: regs->regs[1] = args[5];
+	case 5: regs->regs[0] = args[4];
+	case 4: regs->regs[7] = args[3];
+	case 3: regs->regs[6] = args[2];
+	case 2: regs->regs[5] = args[1];
+	case 1: regs->regs[4] = args[0];
+		break;
+	default:
+		BUG();
+	}
+}
+
+#endif /* __ASM_SH_SYSCALL_32_H */

arch/sh/include/asm/syscall_64.h

+#ifndef __ASM_SH_SYSCALL_64_H
+#define __ASM_SH_SYSCALL_64_H
+
+#include <asm-generic/syscall.h>
+
+#endif /* __ASM_SH_SYSCALL_64_H */