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-rw-r--r--arch/powerpc/kernel/softemu8xx.c202
1 files changed, 202 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/softemu8xx.c b/arch/powerpc/kernel/softemu8xx.c
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1/*
2 * Software emulation of some PPC instructions for the 8xx core.
3 *
4 * Copyright (C) 1998 Dan Malek (dmalek@jlc.net)
5 *
6 * Software floating emuation for the MPC8xx processor. I did this mostly
7 * because it was easier than trying to get the libraries compiled for
8 * software floating point. The goal is still to get the libraries done,
9 * but I lost patience and needed some hacks to at least get init and
10 * shells running. The first problem is the setjmp/longjmp that save
11 * and restore the floating point registers.
12 *
13 * For this emulation, our working registers are found on the register
14 * save area.
15 */
16
17#include <linux/errno.h>
18#include <linux/sched.h>
19#include <linux/kernel.h>
20#include <linux/mm.h>
21#include <linux/stddef.h>
22#include <linux/unistd.h>
23#include <linux/ptrace.h>
24#include <linux/slab.h>
25#include <linux/user.h>
26#include <linux/a.out.h>
27#include <linux/interrupt.h>
28
29#include <asm/pgtable.h>
30#include <asm/uaccess.h>
31#include <asm/system.h>
32#include <asm/io.h>
33
34/* Eventually we may need a look-up table, but this works for now.
35*/
36#define LFS 48
37#define LFD 50
38#define LFDU 51
39#define STFD 54
40#define STFDU 55
41#define FMR 63
42
43void print_8xx_pte(struct mm_struct *mm, unsigned long addr)
44{
45 pgd_t *pgd;
46 pmd_t *pmd;
47 pte_t *pte;
48
49 printk(" pte @ 0x%8lx: ", addr);
50 pgd = pgd_offset(mm, addr & PAGE_MASK);
51 if (pgd) {
52 pmd = pmd_offset(pud_offset(pgd, addr & PAGE_MASK),
53 addr & PAGE_MASK);
54 if (pmd && pmd_present(*pmd)) {
55 pte = pte_offset_kernel(pmd, addr & PAGE_MASK);
56 if (pte) {
57 printk(" (0x%08lx)->(0x%08lx)->0x%08lx\n",
58 (long)pgd, (long)pte, (long)pte_val(*pte));
59#define pp ((long)pte_val(*pte))
60 printk(" RPN: %05lx PP: %lx SPS: %lx SH: %lx "
61 "CI: %lx v: %lx\n",
62 pp>>12, /* rpn */
63 (pp>>10)&3, /* pp */
64 (pp>>3)&1, /* small */
65 (pp>>2)&1, /* shared */
66 (pp>>1)&1, /* cache inhibit */
67 pp&1 /* valid */
68 );
69#undef pp
70 }
71 else {
72 printk("no pte\n");
73 }
74 }
75 else {
76 printk("no pmd\n");
77 }
78 }
79 else {
80 printk("no pgd\n");
81 }
82}
83
84int get_8xx_pte(struct mm_struct *mm, unsigned long addr)
85{
86 pgd_t *pgd;
87 pmd_t *pmd;
88 pte_t *pte;
89 int retval = 0;
90
91 pgd = pgd_offset(mm, addr & PAGE_MASK);
92 if (pgd) {
93 pmd = pmd_offset(pud_offset(pgd, addr & PAGE_MASK),
94 addr & PAGE_MASK);
95 if (pmd && pmd_present(*pmd)) {
96 pte = pte_offset_kernel(pmd, addr & PAGE_MASK);
97 if (pte) {
98 retval = (int)pte_val(*pte);
99 }
100 }
101 }
102 return retval;
103}
104
105/*
106 * We return 0 on success, 1 on unimplemented instruction, and EFAULT
107 * if a load/store faulted.
108 */
109int Soft_emulate_8xx(struct pt_regs *regs)
110{
111 u32 inst, instword;
112 u32 flreg, idxreg, disp;
113 int retval;
114 s16 sdisp;
115 u32 *ea, *ip;
116
117 retval = 0;
118
119 instword = *((u32 *)regs->nip);
120 inst = instword >> 26;
121
122 flreg = (instword >> 21) & 0x1f;
123 idxreg = (instword >> 16) & 0x1f;
124 disp = instword & 0xffff;
125
126 ea = (u32 *)(regs->gpr[idxreg] + disp);
127 ip = (u32 *)&current->thread.fpr[flreg];
128
129 switch ( inst )
130 {
131 case LFD:
132 /* this is a 16 bit quantity that is sign extended
133 * so use a signed short here -- Cort
134 */
135 sdisp = (instword & 0xffff);
136 ea = (u32 *)(regs->gpr[idxreg] + sdisp);
137 if (copy_from_user(ip, ea, sizeof(double)))
138 retval = -EFAULT;
139 break;
140
141 case LFDU:
142 if (copy_from_user(ip, ea, sizeof(double)))
143 retval = -EFAULT;
144 else
145 regs->gpr[idxreg] = (u32)ea;
146 break;
147 case LFS:
148 sdisp = (instword & 0xffff);
149 ea = (u32 *)(regs->gpr[idxreg] + sdisp);
150 if (copy_from_user(ip, ea, sizeof(float)))
151 retval = -EFAULT;
152 break;
153 case STFD:
154 /* this is a 16 bit quantity that is sign extended
155 * so use a signed short here -- Cort
156 */
157 sdisp = (instword & 0xffff);
158 ea = (u32 *)(regs->gpr[idxreg] + sdisp);
159 if (copy_to_user(ea, ip, sizeof(double)))
160 retval = -EFAULT;
161 break;
162
163 case STFDU:
164 if (copy_to_user(ea, ip, sizeof(double)))
165 retval = -EFAULT;
166 else
167 regs->gpr[idxreg] = (u32)ea;
168 break;
169 case FMR:
170 /* assume this is a fp move -- Cort */
171 memcpy(ip, &current->thread.fpr[(instword>>11)&0x1f],
172 sizeof(double));
173 break;
174 default:
175 retval = 1;
176 printk("Bad emulation %s/%d\n"
177 " NIP: %08lx instruction: %08x opcode: %x "
178 "A: %x B: %x C: %x code: %x rc: %x\n",
179 current->comm,current->pid,
180 regs->nip,
181 instword,inst,
182 (instword>>16)&0x1f,
183 (instword>>11)&0x1f,
184 (instword>>6)&0x1f,
185 (instword>>1)&0x3ff,
186 instword&1);
187 {
188 int pa;
189 print_8xx_pte(current->mm,regs->nip);
190 pa = get_8xx_pte(current->mm,regs->nip) & PAGE_MASK;
191 pa |= (regs->nip & ~PAGE_MASK);
192 pa = (unsigned long)__va(pa);
193 printk("Kernel VA for NIP %x ", pa);
194 print_8xx_pte(current->mm,pa);
195 }
196 }
197
198 if (retval == 0)
199 regs->nip += 4;
200
201 return retval;
202}
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