/*
* Software emulation of some PPC instructions for the 8xx core.
*
* Copyright (C) 1998 Dan Malek (dmalek@jlc.net)
*
* Software floating emuation for the MPC8xx processor. I did this mostly
* because it was easier than trying to get the libraries compiled for
* software floating point. The goal is still to get the libraries done,
* but I lost patience and needed some hacks to at least get init and
* shells running. The first problem is the setjmp/longjmp that save
* and restore the floating point registers.
*
* For this emulation, our working registers are found on the register
* save area.
*/
#include <linux/errno.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/stddef.h>
#include <linux/unistd.h>
#include <linux/ptrace.h>
#include <linux/slab.h>
#include <linux/user.h>
#include <linux/a.out.h>
#include <linux/interrupt.h>
#include <asm/pgtable.h>
#include <asm/uaccess.h>
#include <asm/system.h>
#include <asm/io.h>
/* Eventually we may need a look-up table, but this works for now.
*/
#define LFS 48
#define LFD 50
#define LFDU 51
#define STFD 54
#define STFDU 55
#define FMR 63
void print_8xx_pte(struct mm_struct *mm, unsigned long addr)
{
pgd_t *pgd;
pmd_t *pmd;
pte_t *pte;
printk(" pte @ 0x%8lx: ", addr);
pgd = pgd_offset(mm, addr & PAGE_MASK);
if (pgd) {
pmd = pmd_offset(pud_offset(pgd, addr & PAGE_MASK),
addr & PAGE_MASK);
if (pmd && pmd_present(*pmd)) {
pte = pte_offset_kernel(pmd, addr & PAGE_MASK);
if (pte) {
printk(" (0x%08lx)->(0x%08lx)->0x%08lx\n",
(long)pgd, (long)pte, (long)pte_val(*pte));
#define pp ((long)pte_val(*pte))
printk(" RPN: %05lx PP: %lx SPS: %lx SH: %lx "
"CI: %lx v: %lx\n",
pp>>12, /* rpn */
(pp>>10)&3, /* pp */
(pp>>3)&1, /* small */
(pp>>2)&1, /* shared */
(pp>>1)&1, /* cache inhibit */
pp&1 /* valid */
);
#undef pp
}
else {
printk("no pte\n");
}
}
else {
printk("no pmd\n");
}
}
else {
printk("no pgd\n");
}
}
int get_8xx_pte(struct mm_struct *mm, unsigned long addr)
{
pgd_t *pgd;
pmd_t *pmd;
pte_t *pte;
int retval = 0;
pgd = pgd_offset(mm, addr & PAGE_MASK);
if (pgd) {
pmd = pmd_offset(pud_offset(pgd, addr & PAGE_MASK),
addr & PAGE_MASK);
if (pmd && pmd_present(*pmd)) {
pte = pte_offset_kernel(pmd, addr & PAGE_MASK);
if (pte) {
retval = (int)pte_val(*pte);
}
}
}
return retval;
}
/*
* We return 0 on success, 1 on unimplemented instruction, and EFAULT
* if a load/store faulted.
*/
int Soft_emulate_8xx(struct pt_regs *regs)
{
u32 inst, instword;
u32 flreg, idxreg, disp;
int retval;
s16 sdisp;
u32 *ea, *ip;
retval = 0;
instword = *((u32 *)regs->nip);
inst = instword >> 26;
flreg = (instword >> 21) & 0x1f;
idxreg = (instword >> 16) & 0x1f;
disp = instword & 0xffff;
ea = (u32 *)(regs->gpr[idxreg] + disp);
ip = (u32 *)¤t->thread.fpr[flreg];
switch ( inst )
{
case LFD:
/* this is a 16 bit quantity that is sign extended
* so use a signed short here -- Cort
*/
sdisp = (instword & 0xffff);
ea = (u32 *)(regs->gpr[idxreg] + sdisp);
if (copy_from_user(ip, ea, sizeof(double)))
retval = -EFAULT;
break;
case LFDU:
if (copy_from_user(ip, ea, sizeof(double)))
retval = -EFAULT;
else
regs->gpr[idxreg] = (u32)ea;
break;
case LFS:
sdisp = (instword & 0xffff);
ea = (u32 *)(regs->gpr[idxreg] + sdisp);
if (copy_from_user(ip, ea, sizeof(float)))
retval = -EFAULT;
break;
case STFD:
/* this is a 16 bit quantity that is sign extended
* so use a signed short here -- Cort
*/
sdisp = (instword & 0xffff);
ea = (u32 *)(regs->gpr[idxreg] + sdisp);
if (copy_to_user(ea, ip, sizeof(double)))
retval = -EFAULT;
break;
case STFDU:
if (copy_to_user(ea, ip, sizeof(double)))
retval = -EFAULT;
else
regs->gpr[idxreg] = (u32)ea;
break;
case FMR:
/* assume this is a fp move -- Cort */
memcpy(ip, ¤t->thread.fpr[(instword>>11)&0x1f],
sizeof(double));
break;
default:
retval = 1;
printk("Bad emulation %s/%d\n"
" NIP: %08lx instruction: %08x opcode: %x "
"A: %x B: %x C: %x code: %x rc: %x\n",
current->comm,current->pid,
regs->nip,
instword,inst,
(instword>>16)&0x1f,
(instword>>11)&0x1f,
(instword>>6)&0x1f,
(instword>>1)&0x3ff,
instword&1);
{
int pa;
print_8xx_pte(current->mm,regs->nip);
pa = get_8xx_pte(current->mm,regs->nip) & PAGE_MASK;
pa |= (regs->nip & ~PAGE_MASK);
pa = (unsigned long)__va(pa);
printk("Kernel VA for NIP %x ", pa);
print_8xx_pte(current->mm,pa);
}
}
if (retval == 0)
regs->nip += 4;
return retval;
}
