1// SPDX-License-Identifier: GPL-2.0-or-later
2
3#include <linux/regset.h>
4#include <linux/elf.h>
5
6#include <asm/switch_to.h>
7
8#include "ptrace-decl.h"
9
10/*
11 * Get/set all the altivec registers vr0..vr31, vscr, vrsave, in one go.
12 * The transfer totals 34 quadword.  Quadwords 0-31 contain the
13 * corresponding vector registers.  Quadword 32 contains the vscr as the
14 * last word (offset 12) within that quadword.  Quadword 33 contains the
15 * vrsave as the first word (offset 0) within the quadword.
16 *
17 * This definition of the VMX state is compatible with the current PPC32
18 * ptrace interface.  This allows signal handling and ptrace to use the
19 * same structures.  This also simplifies the implementation of a bi-arch
20 * (combined (32- and 64-bit) gdb.
21 */
22
23int vr_active(struct task_struct *target, const struct user_regset *regset)
24{
25	flush_altivec_to_thread(target);
26	return target->thread.used_vr ? regset->n : 0;
27}
28
29/*
30 * Regardless of transactions, 'vr_state' holds the current running
31 * value of all the VMX registers and 'ckvr_state' holds the last
32 * checkpointed value of all the VMX registers for the current
33 * transaction to fall back on in case it aborts.
34 *
35 * Userspace interface buffer layout:
36 *
37 * struct data {
38 *	vector128	vr[32];
39 *	vector128	vscr;
40 *	vector128	vrsave;
41 * };
42 */
43int vr_get(struct task_struct *target, const struct user_regset *regset,
44	   struct membuf to)
45{
46	union {
47		elf_vrreg_t reg;
48		u32 word;
49	} vrsave;
50
51	flush_altivec_to_thread(target);
52
53	BUILD_BUG_ON(offsetof(struct thread_vr_state, vscr) !=
54		     offsetof(struct thread_vr_state, vr[32]));
55
56	membuf_write(&to, &target->thread.vr_state, 33 * sizeof(vector128));
57	/*
58	 * Copy out only the low-order word of vrsave.
59	 */
60	memset(&vrsave, 0, sizeof(vrsave));
61	vrsave.word = target->thread.vrsave;
62	return membuf_write(&to, &vrsave, sizeof(vrsave));
63}
64
65/*
66 * Regardless of transactions, 'vr_state' holds the current running
67 * value of all the VMX registers and 'ckvr_state' holds the last
68 * checkpointed value of all the VMX registers for the current
69 * transaction to fall back on in case it aborts.
70 *
71 * Userspace interface buffer layout:
72 *
73 * struct data {
74 *	vector128	vr[32];
75 *	vector128	vscr;
76 *	vector128	vrsave;
77 * };
78 */
79int vr_set(struct task_struct *target, const struct user_regset *regset,
80	   unsigned int pos, unsigned int count,
81	   const void *kbuf, const void __user *ubuf)
82{
83	int ret;
84
85	flush_altivec_to_thread(target);
86
87	BUILD_BUG_ON(offsetof(struct thread_vr_state, vscr) !=
88		     offsetof(struct thread_vr_state, vr[32]));
89
90	ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
91				 &target->thread.vr_state, 0,
92				 33 * sizeof(vector128));
93	if (!ret && count > 0) {
94		/*
95		 * We use only the first word of vrsave.
96		 */
97		int start, end;
98		union {
99			elf_vrreg_t reg;
100			u32 word;
101		} vrsave;
102		memset(&vrsave, 0, sizeof(vrsave));
103
104		vrsave.word = target->thread.vrsave;
105
106		start = 33 * sizeof(vector128);
107		end = start + sizeof(vrsave);
108		ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &vrsave,
109					 start, end);
110		if (!ret)
111			target->thread.vrsave = vrsave.word;
112	}
113
114	return ret;
115}
116