1/*
  2 *  linux/arch/h8300/kernel/ptrace.c
  3 *
  4 *  Copyright 2015 Yoshinori Sato <ysato@users.sourceforge.jp>
  5 *
  6 * This file is subject to the terms and conditions of the GNU General
  7 * Public License.  See the file COPYING in the main directory of
  8 * this archive for more details.
  9 */
 10
 11#include <linux/kernel.h>
 12#include <linux/errno.h>
 13#include <linux/ptrace.h>
 14#include <linux/audit.h>
 15#include <linux/tracehook.h>
 16#include <linux/regset.h>
 17#include <linux/elf.h>
 18
 19#define CCR_MASK 0x6f    /* mode/imask not set */
 20#define EXR_MASK 0x80    /* modify only T */
 21
 22#define PT_REG(r) offsetof(struct pt_regs, r)
 23
 24extern void user_disable_single_step(struct task_struct *child);
 25
 26/* Mapping from PT_xxx to the stack offset at which the register is
 27   saved.  Notice that usp has no stack-slot and needs to be treated
 28   specially (see get_reg/put_reg below). */
 29static const int register_offset[] = {
 30	PT_REG(er1), PT_REG(er2), PT_REG(er3), PT_REG(er4),
 31	PT_REG(er5), PT_REG(er6), PT_REG(er0), -1,
 32	PT_REG(orig_er0), PT_REG(ccr), PT_REG(pc),
 33#if defined(CONFIG_CPU_H8S)
 34	PT_REG(exr),
 35#endif
 36};
 37
 38/* read register */
 39long h8300_get_reg(struct task_struct *task, int regno)
 40{
 41	switch (regno) {
 42	case PT_USP:
 43		return task->thread.usp + sizeof(long)*2;
 44	case PT_CCR:
 45	case PT_EXR:
 46	    return *(unsigned short *)(task->thread.esp0 +
 47				       register_offset[regno]);
 48	default:
 49	    return *(unsigned long *)(task->thread.esp0 +
 50				      register_offset[regno]);
 51	}
 52}
 53
 54int h8300_put_reg(struct task_struct *task, int regno, unsigned long data)
 55{
 56	unsigned short oldccr;
 57	unsigned short oldexr;
 58
 59	switch (regno) {
 60	case PT_USP:
 61		task->thread.usp = data - sizeof(long)*2;
 62	case PT_CCR:
 63		oldccr = *(unsigned short *)(task->thread.esp0 +
 64					     register_offset[regno]);
 65		oldccr &= ~CCR_MASK;
 66		data &= CCR_MASK;
 67		data |= oldccr;
 68		*(unsigned short *)(task->thread.esp0 +
 69				    register_offset[regno]) = data;
 70		break;
 71	case PT_EXR:
 72		oldexr = *(unsigned short *)(task->thread.esp0 +
 73					     register_offset[regno]);
 74		oldccr &= ~EXR_MASK;
 75		data &= EXR_MASK;
 76		data |= oldexr;
 77		*(unsigned short *)(task->thread.esp0 +
 78				    register_offset[regno]) = data;
 79		break;
 80	default:
 81		*(unsigned long *)(task->thread.esp0 +
 82				   register_offset[regno]) = data;
 83		break;
 84	}
 85	return 0;
 86}
 87
 88static int regs_get(struct task_struct *target,
 89		    const struct user_regset *regset,
 90		    unsigned int pos, unsigned int count,
 91		    void *kbuf, void __user *ubuf)
 92{
 93	int r;
 94	struct user_regs_struct regs;
 95	long *reg = (long *)&regs;
 96
 97	/* build user regs in buffer */
 98	BUILD_BUG_ON(sizeof(regs) % sizeof(long) != 0);
 99	for (r = 0; r < sizeof(regs) / sizeof(long); r++)
100		*reg++ = h8300_get_reg(target, r);
101
102	return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
103				   &regs, 0, sizeof(regs));
104}
105
106static int regs_set(struct task_struct *target,
107		    const struct user_regset *regset,
108		    unsigned int pos, unsigned int count,
109		    const void *kbuf, const void __user *ubuf)
110{
111	int r;
112	int ret;
113	struct user_regs_struct regs;
114	long *reg;
115
116	/* build user regs in buffer */
117	BUILD_BUG_ON(sizeof(regs) % sizeof(long) != 0);
118	for (reg = (long *)&regs, r = 0; r < sizeof(regs) / sizeof(long); r++)
119		*reg++ = h8300_get_reg(target, r);
120
121	ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
122				 &regs, 0, sizeof(regs));
123	if (ret)
124		return ret;
125
126	/* write back to pt_regs */
127	for (reg = (long *)&regs, r = 0; r < sizeof(regs) / sizeof(long); r++)
128		h8300_put_reg(target, r, *reg++);
129	return 0;
130}
131
132enum h8300_regset {
133	REGSET_GENERAL,
134};
135
136static const struct user_regset h8300_regsets[] = {
137	[REGSET_GENERAL] = {
138		.core_note_type	= NT_PRSTATUS,
139		.n		= ELF_NGREG,
140		.size		= sizeof(long),
141		.align		= sizeof(long),
142		.get		= regs_get,
143		.set		= regs_set,
144	},
145};
146
147static const struct user_regset_view user_h8300_native_view = {
148	.name = "h8300",
149	.e_machine = EM_H8_300,
150	.regsets = h8300_regsets,
151	.n = ARRAY_SIZE(h8300_regsets),
152};
153
154const struct user_regset_view *task_user_regset_view(struct task_struct *task)
155{
156	return &user_h8300_native_view;
157}
158
159void ptrace_disable(struct task_struct *child)
160{
161	user_disable_single_step(child);
162}
163
164long arch_ptrace(struct task_struct *child, long request,
165		 unsigned long addr, unsigned long data)
166{
167	int ret;
168
169	switch (request) {
170	default:
171		ret = ptrace_request(child, request, addr, data);
172		break;
173	}
174	return ret;
175}
176
177asmlinkage long do_syscall_trace_enter(struct pt_regs *regs)
178{
179	long ret = 0;
180
181	if (test_thread_flag(TIF_SYSCALL_TRACE) &&
182	    tracehook_report_syscall_entry(regs))
183		/*
184		 * Tracing decided this syscall should not happen.
185		 * We'll return a bogus call number to get an ENOSYS
186		 * error, but leave the original number in regs->regs[0].
187		 */
188		ret = -1L;
189
190	audit_syscall_entry(regs->er1, regs->er2, regs->er3,
191			    regs->er4, regs->er5);
192
193	return ret ?: regs->er0;
194}
195
196asmlinkage void do_syscall_trace_leave(struct pt_regs *regs)
197{
198	int step;
199
200	audit_syscall_exit(regs);
201
202	step = test_thread_flag(TIF_SINGLESTEP);
203	if (step || test_thread_flag(TIF_SYSCALL_TRACE))
204		tracehook_report_syscall_exit(regs, step);
205}