diff options
Diffstat (limited to 'arch/ppc/kernel/softemu8xx.c')
| -rw-r--r-- | arch/ppc/kernel/softemu8xx.c | 147 |
1 files changed, 147 insertions, 0 deletions
diff --git a/arch/ppc/kernel/softemu8xx.c b/arch/ppc/kernel/softemu8xx.c new file mode 100644 index 000000000000..9bbb6bf7b645 --- /dev/null +++ b/arch/ppc/kernel/softemu8xx.c @@ -0,0 +1,147 @@ +/* + * 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> + +extern void +print_8xx_pte(struct mm_struct *mm, unsigned long addr); +extern int +get_8xx_pte(struct mm_struct *mm, unsigned long addr); + +/* 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 + +/* + * We return 0 on success, 1 on unimplemented instruction, and EFAULT + * if a load/store faulted. + */ +int +Soft_emulate_8xx(struct pt_regs *regs) +{ + uint inst, instword; + uint flreg, idxreg, disp; + uint retval; + signed short sdisp; + uint *ea, *ip; + + retval = 0; + + instword = *((uint *)regs->nip); + inst = instword >> 26; + + flreg = (instword >> 21) & 0x1f; + idxreg = (instword >> 16) & 0x1f; + disp = instword & 0xffff; + + ea = (uint *)(regs->gpr[idxreg] + disp); + ip = (uint *)¤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 = (uint *)(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] = (uint)ea; + break; + case LFS: + sdisp = (instword & 0xffff); + ea = (uint *)(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 = (uint *)(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] = (uint)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); +} + |