FRV: Implement new-style ptrace

Implement the new-style ptrace for FRV, including adding appropriate
tracehooks.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

arch/frv/Kconfig

@@ -6,6 +6,7 @@ config FRV
 	bool
 	default y
 	select HAVE_IDE
+	select HAVE_ARCH_TRACEHOOK
 
 config ZONE_DMA
 	bool

arch/frv/include/asm/elf.h

@@ -116,6 +116,7 @@ do {											\
 } while(0)
 
 #define USE_ELF_CORE_DUMP
+#define CORE_DUMP_USE_REGSET
 #define ELF_FDPIC_CORE_EFLAGS	EF_FRV_FDPIC
 #define ELF_EXEC_PAGESIZE	16384
 

arch/frv/include/asm/ptrace.h

@@ -65,6 +65,8 @@
 #ifdef __KERNEL__
 #ifndef __ASSEMBLY__
 
+struct task_struct;
+
 /*
  * we dedicate GR28 to keeping a pointer to the current exception frame
  * - gr28 is destroyed on entry to the kernel from userspace
@@ -73,11 +75,18 @@ register struct pt_regs *__frame asm("gr28");
 
 #define user_mode(regs)			(!((regs)->psr & PSR_S))
 #define instruction_pointer(regs)	((regs)->pc)
+#define user_stack_pointer(regs)	((regs)->sp)
 
 extern unsigned long user_stack(const struct pt_regs *);
 extern void show_regs(struct pt_regs *);
 #define profile_pc(regs) ((regs)->pc)
-#endif
+
+#define task_pt_regs(task) ((task)->thread.frame0)
+
+#define arch_has_single_step()	(1)
+extern void user_enable_single_step(struct task_struct *);
+extern void user_disable_single_step(struct task_struct *);
 
 #endif /* !__ASSEMBLY__ */
+#endif /* __KERNEL__ */
 #endif /* _ASM_PTRACE_H */

arch/frv/include/asm/syscall.h

@@ -0,0 +1,123 @@
+/* syscall parameter access functions
+ *
+ * Copyright (C) 2009 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public Licence
+ * as published by the Free Software Foundation; either version
+ * 2 of the Licence, or (at your option) any later version.
+ */
+
+#ifndef _ASM_SYSCALL_H
+#define _ASM_SYSCALL_H
+
+#include <linux/err.h>
+#include <asm/ptrace.h>
+
+/*
+ * Get the system call number or -1
+ */
+static inline long syscall_get_nr(struct task_struct *task,
+				  struct pt_regs *regs)
+{
+	return regs->syscallno;
+}
+
+/*
+ * Restore the clobbered GR8 register
+ * (1st syscall arg was overwritten with syscall return or error)
+ */
+static inline void syscall_rollback(struct task_struct *task,
+				    struct pt_regs *regs)
+{
+	regs->gr8 = regs->orig_gr8;
+}
+
+/*
+ * See if the syscall return value is an error, returning it if it is and 0 if
+ * not
+ */
+static inline long syscall_get_error(struct task_struct *task,
+				     struct pt_regs *regs)
+{
+	return IS_ERR_VALUE(regs->gr8) ? regs->gr8 : 0;
+}
+
+/*
+ * Get the syscall return value
+ */
+static inline long syscall_get_return_value(struct task_struct *task,
+					    struct pt_regs *regs)
+{
+	return regs->gr8;
+}
+
+/*
+ * Set the syscall return value
+ */
+static inline void syscall_set_return_value(struct task_struct *task,
+					    struct pt_regs *regs,
+					    int error, long val)
+{
+	if (error)
+		regs->gr8 = -error;
+	else
+		regs->gr8 = val;
+}
+
+/*
+ * Retrieve the system call arguments
+ */
+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: GR8, GR9, GR10, GR11, GR12, GR13 */
+	switch (n) {
+	case 6: args[5] = regs->gr13;
+	case 5: args[4] = regs->gr12;
+	case 4: args[3] = regs->gr11;
+	case 3: args[2] = regs->gr10;
+	case 2: args[1] = regs->gr9;
+	case 1:	args[0] = regs->gr8;
+		break;
+	default:
+		BUG();
+	}
+}
+
+/*
+ * Alter the system call arguments
+ */
+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->gr13 = args[5];
+	case 5: regs->gr12 = args[4];
+	case 4: regs->gr11 = args[3];
+	case 3: regs->gr10 = args[2];
+	case 2: regs->gr9  = args[1];
+	case 1: regs->gr8  = args[0];
+		break;
+	default:
+		BUG();
+	}
+}
+
+#endif /* _ASM_SYSCALL_H */

arch/frv/kernel/entry.S

@@ -1149,11 +1149,10 @@ __entry_work_notifysig:
 	# perform syscall entry tracing
 __syscall_trace_entry:
 	LEDS		0x6320
-	setlos.p	#0,gr8
-	call		do_syscall_trace
+	call		syscall_trace_entry
 
-	ldi		@(gr28,#REG_SYSCALLNO),gr7
-	lddi		@(gr28,#REG_GR(8)) ,gr8
+	lddi.p		@(gr28,#REG_GR(8)) ,gr8
+	ori		gr8,#0,gr7		; syscall_trace_entry() returned new syscallno
 	lddi		@(gr28,#REG_GR(10)),gr10
 	lddi.p		@(gr28,#REG_GR(12)),gr12
 
@@ -1168,11 +1167,10 @@ __syscall_exit_work:
 	beq		icc0,#1,__entry_work_pending
 
 	movsg		psr,gr23
-	andi		gr23,#~PSR_PIL,gr23	; could let do_syscall_trace() call schedule()
+	andi		gr23,#~PSR_PIL,gr23	; could let syscall_trace_exit() call schedule()
 	movgs		gr23,psr
 
-	setlos.p	#1,gr8
-	call		do_syscall_trace
+	call		syscall_trace_exit
 	bra		__entry_resume_userspace
 
 __syscall_badsys: