ptrace.c

  1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * Ptrace support for Hexagon
  4 *
  5 * Copyright (c) 2010-2013, The Linux Foundation. All rights reserved.
  6 */
  7
  8#include <linux/kernel.h>
  9#include <linux/sched.h>
 10#include <linux/sched/task_stack.h>
 11#include <linux/mm.h>
 12#include <linux/smp.h>
 13#include <linux/errno.h>
 14#include <linux/ptrace.h>
 15#include <linux/regset.h>
 16#include <linux/user.h>
 17#include <linux/elf.h>
 18
 19#include <asm/user.h>
 20
 21#if arch_has_single_step()
 22/*  Both called from ptrace_resume  */
 23void user_enable_single_step(struct task_struct *child)
 24{
 25	pt_set_singlestep(task_pt_regs(child));
 26	set_tsk_thread_flag(child, TIF_SINGLESTEP);
 27}
 28
 29void user_disable_single_step(struct task_struct *child)
 30{
 31	pt_clr_singlestep(task_pt_regs(child));
 32	clear_tsk_thread_flag(child, TIF_SINGLESTEP);
 33}
 34#endif
 35
 36static int genregs_get(struct task_struct *target,
 37		   const struct user_regset *regset,
 38		   struct membuf to)
 39{
 40	struct pt_regs *regs = task_pt_regs(target);
 41
 42	/* The general idea here is that the copyout must happen in
 43	 * exactly the same order in which the userspace expects these
 44	 * regs. Now, the sequence in userspace does not match the
 45	 * sequence in the kernel, so everything past the 32 gprs
 46	 * happens one at a time.
 47	 */
 48	membuf_write(&to, &regs->r00, 32*sizeof(unsigned long));
 49	/* Must be exactly same sequence as struct user_regs_struct */
 50	membuf_store(&to, regs->sa0);
 51	membuf_store(&to, regs->lc0);
 52	membuf_store(&to, regs->sa1);
 53	membuf_store(&to, regs->lc1);
 54	membuf_store(&to, regs->m0);
 55	membuf_store(&to, regs->m1);
 56	membuf_store(&to, regs->usr);
 57	membuf_store(&to, regs->preds);
 58	membuf_store(&to, regs->gp);
 59	membuf_store(&to, regs->ugp);
 60	membuf_store(&to, pt_elr(regs)); // pc
 61	membuf_store(&to, (unsigned long)pt_cause(regs)); // cause
 62	membuf_store(&to, pt_badva(regs)); // badva
 63#if CONFIG_HEXAGON_ARCH_VERSION >=4
 64	membuf_store(&to, regs->cs0);
 65	membuf_store(&to, regs->cs1);
 66	return membuf_zero(&to, sizeof(unsigned long));
 67#else
 68	return membuf_zero(&to, 3 * sizeof(unsigned long));
 69#endif
 70}
 71
 72static int genregs_set(struct task_struct *target,
 73		   const struct user_regset *regset,
 74		   unsigned int pos, unsigned int count,
 75		   const void *kbuf, const void __user *ubuf)
 76{
 77	int ret, ignore_offset;
 78	unsigned long bucket;
 79	struct pt_regs *regs = task_pt_regs(target);
 80
 81	if (!regs)
 82		return -EIO;
 83
 84	ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
 85				 &regs->r00, 0, 32*sizeof(unsigned long));
 86
 87#define INEXT(KPT_REG, USR_REG) \
 88	if (!ret) \
 89		ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, \
 90			KPT_REG, offsetof(struct user_regs_struct, USR_REG), \
 91			offsetof(struct user_regs_struct, USR_REG) + \
 92				sizeof(unsigned long));
 93
 94	/* Must be exactly same sequence as struct user_regs_struct */
 95	INEXT(&regs->sa0, sa0);
 96	INEXT(&regs->lc0, lc0);
 97	INEXT(&regs->sa1, sa1);
 98	INEXT(&regs->lc1, lc1);
 99	INEXT(&regs->m0, m0);
100	INEXT(&regs->m1, m1);
101	INEXT(&regs->usr, usr);
102	INEXT(&regs->preds, p3_0);
103	INEXT(&regs->gp, gp);
104	INEXT(&regs->ugp, ugp);
105	INEXT(&pt_elr(regs), pc);
106
107	/* CAUSE and BADVA aren't writeable. */
108	INEXT(&bucket, cause);
109	INEXT(&bucket, badva);
110
111#if CONFIG_HEXAGON_ARCH_VERSION >=4
112	INEXT(&regs->cs0, cs0);
113	INEXT(&regs->cs1, cs1);
114	ignore_offset = offsetof(struct user_regs_struct, pad1);
115#else
116	ignore_offset = offsetof(struct user_regs_struct, cs0);
117#endif
118
119	/* Ignore the rest, if needed */
120	if (!ret)
121		user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
122					  ignore_offset, -1);
123	else
124		return ret;
125
126	/*
127	 * This is special; SP is actually restored by the VM via the
128	 * special event record which is set by the special trap.
129	 */
130	regs->hvmer.vmpsp = regs->r29;
131	return 0;
132}
133
134enum hexagon_regset {
135	REGSET_GENERAL,
136};
137
138static const struct user_regset hexagon_regsets[] = {
139	[REGSET_GENERAL] = {
140		USER_REGSET_NOTE_TYPE(PRSTATUS),
141		.n = ELF_NGREG,
142		.size = sizeof(unsigned long),
143		.align = sizeof(unsigned long),
144		.regset_get = genregs_get,
145		.set = genregs_set,
146	},
147};
148
149static const struct user_regset_view hexagon_user_view = {
150	.name = "hexagon",
151	.e_machine = ELF_ARCH,
152	.ei_osabi = ELF_OSABI,
153	.regsets = hexagon_regsets,
154	.e_flags = ELF_CORE_EFLAGS,
155	.n = ARRAY_SIZE(hexagon_regsets)
156};
157
158const struct user_regset_view *task_user_regset_view(struct task_struct *task)
159{
160	return &hexagon_user_view;
161}
162
163void ptrace_disable(struct task_struct *child)
164{
165	/* Boilerplate - resolves to null inline if no HW single-step */
166	user_disable_single_step(child);
167}
168
169long arch_ptrace(struct task_struct *child, long request,
170		 unsigned long addr, unsigned long data)
171{
172	return ptrace_request(child, request, addr, data);
173}