[IA64] utrace syscall.h support for ia64

Add asm/syscall.h for IA64. Utrace requires this.
Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>

arch/ia64/include/asm/ptrace.h

@@ -240,6 +240,12 @@ struct switch_stack {
  */
 # define instruction_pointer(regs) ((regs)->cr_iip + ia64_psr(regs)->ri)
 
+static inline unsigned long user_stack_pointer(struct pt_regs *regs)
+{
+	/* FIXME: should this be bspstore + nr_dirty regs? */
+	return regs->ar_bspstore;
+}
+
 #define regs_return_value(regs) ((regs)->r8)
 
 /* Conserve space in histogram by encoding slot bits in address

arch/ia64/include/asm/syscall.h

+/*
+ * Access to user system call parameters and results
+ *
+ * Copyright (C) 2008 Intel Corp.  Shaohua Li <shaohua.li@intel.com>
+ *
+ * This copyrighted material is made available to anyone wishing to use,
+ * modify, copy, or redistribute it subject to the terms and conditions
+ * of the GNU General Public License v.2.
+ *
+ * See asm-generic/syscall.h for descriptions of what we must do here.
+ */
+
+#ifndef _ASM_SYSCALL_H
+#define _ASM_SYSCALL_H	1
+
+#include <linux/sched.h>
+#include <linux/err.h>
+
+static inline long syscall_get_nr(struct task_struct *task,
+				  struct pt_regs *regs)
+{
+	BUG_ON(IS_IA32_PROCESS(regs));
+
+	if ((long)regs->cr_ifs < 0) /* Not a syscall */
+		return -1;
+	return regs->r15;
+}
+
+static inline void syscall_rollback(struct task_struct *task,
+				    struct pt_regs *regs)
+{
+	BUG_ON(IS_IA32_PROCESS(regs));
+	/* do nothing */
+}
+
+static inline long syscall_get_error(struct task_struct *task,
+				     struct pt_regs *regs)
+{
+	BUG_ON(IS_IA32_PROCESS(regs));
+
+	return regs->r10 == -1 ? regs->r8:0;
+}
+
+static inline long syscall_get_return_value(struct task_struct *task,
+					    struct pt_regs *regs)
+{
+	BUG_ON(IS_IA32_PROCESS(regs));
+
+	return regs->r8;
+}
+
+static inline void syscall_set_return_value(struct task_struct *task,
+					    struct pt_regs *regs,
+					    int error, long val)
+{
+	BUG_ON(IS_IA32_PROCESS(regs));
+
+	if (error) {
+		/* error < 0, but ia64 uses > 0 return value */
+		regs->r8 = -error;
+		regs->r10 = -1;
+	} else {
+		regs->r8 = val;
+		regs->r10 = 0;
+	}
+}
+
+extern void ia64_syscall_get_set_arguments(struct task_struct *task,
+	struct pt_regs *regs, unsigned int i, unsigned int n,
+	unsigned long *args, int rw);
+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(IS_IA32_PROCESS(regs));
+	BUG_ON(i + n > 6);
+
+	ia64_syscall_get_set_arguments(task, regs, i, n, args, 0);
+}
+
+static inline void syscall_set_arguments(struct task_struct *task,
+					 struct pt_regs *regs,
+					 unsigned int i, unsigned int n,
+					 unsigned long *args)
+{
+	BUG_ON(IS_IA32_PROCESS(regs));
+	BUG_ON(i + n > 6);
+
+	ia64_syscall_get_set_arguments(task, regs, i, n, args, 1);
+}
+#endif	/* _ASM_SYSCALL_H */

arch/ia64/kernel/ptrace.c

@@ -2199,3 +2199,68 @@ const struct user_regset_view *task_user_regset_view(struct task_struct *tsk)
 #endif
 	return &user_ia64_view;
 }
+
+struct syscall_get_set_args {
+	unsigned int i;
+	unsigned int n;
+	unsigned long *args;
+	struct pt_regs *regs;
+	int rw;
+};
+
+static void syscall_get_set_args_cb(struct unw_frame_info *info, void *data)
+{
+	struct syscall_get_set_args *args = data;
+	struct pt_regs *pt = args->regs;
+	unsigned long *krbs, cfm, ndirty;
+	int i, count;
+
+	if (unw_unwind_to_user(info) < 0)
+		return;
+
+	cfm = pt->cr_ifs;
+	krbs = (unsigned long *)info->task + IA64_RBS_OFFSET/8;
+	ndirty = ia64_rse_num_regs(krbs, krbs + (pt->loadrs >> 19));
+
+	count = 0;
+	if (in_syscall(pt))
+		count = min_t(int, args->n, cfm & 0x7f);
+
+	for (i = 0; i < count; i++) {
+		if (args->rw)
+			*ia64_rse_skip_regs(krbs, ndirty + i + args->i) =
+				args->args[i];
+		else
+			args->args[i] = *ia64_rse_skip_regs(krbs,
+				ndirty + i + args->i);
+	}
+
+	if (!args->rw) {
+		while (i < args->n) {
+			args->args[i] = 0;
+			i++;
+		}
+	}
+}
+
+void ia64_syscall_get_set_arguments(struct task_struct *task,
+	struct pt_regs *regs, unsigned int i, unsigned int n,
+	unsigned long *args, int rw)
+{
+	struct syscall_get_set_args data = {
+		.i = i,
+		.n = n,
+		.args = args,
+		.regs = regs,
+		.rw = rw,
+	};
+
+	if (task == current)
+		unw_init_running(syscall_get_set_args_cb, &data);
+	else {
+		struct unw_frame_info ufi;
+		memset(&ufi, 0, sizeof(ufi));
+		unw_init_from_blocked_task(&ufi, task);
+		syscall_get_set_args_cb(&ufi, &data);
+	}
+}