提交 5dd57a13 编写于 作者: S Scott Wood 提交者: Kumar Gala

[POWERPC] 8xx: Move softemu8xx.c from arch/ppc

Previously, Soft_emulate_8xx was called with no implementation, resulting in
build failures whenever building 8xx without math emulation.  The
implementation is copied from arch/ppc to resolve this issue.

However, this sort of minimal emulation is not a very good idea other than
for compatibility with existing userspaces, as it's less efficient than
soft-float and can mislead users into believing they have soft-float.  Thus,
it is made a configurable option, off by default.
Signed-off-by: NScott Wood <scottwood@freescale.com>
Signed-off-by: NKumar Gala <galak@kernel.crashing.org>
上级 c4e05bc5
......@@ -198,6 +198,17 @@ config MATH_EMULATION
unit, which will allow programs that use floating-point
instructions to run.
config 8XX_MINIMAL_FPEMU
bool "Minimal math emulation for 8xx"
depends on 8xx && !MATH_EMULATION
help
Older arch/ppc kernels still emulated a few floating point
instructions such as load and store, even when full math
emulation is disabled. Say "Y" here if you want to preserve
this behavior.
It is recommended that you build a soft-float userspace instead.
config IOMMU_VMERGE
bool "Enable IOMMU virtual merging"
depends on PPC64
......
......@@ -75,6 +75,8 @@ obj-$(CONFIG_KEXEC) += machine_kexec.o crash.o \
obj-$(CONFIG_AUDIT) += audit.o
obj64-$(CONFIG_AUDIT) += compat_audit.o
obj-$(CONFIG_8XX_MINIMAL_FPEMU) += softemu8xx.o
ifneq ($(CONFIG_PPC_INDIRECT_IO),y)
obj-y += iomap.o
endif
......
/*
* 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 *)&current->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, &current->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;
}
......@@ -906,7 +906,9 @@ void SoftwareEmulation(struct pt_regs *regs)
{
extern int do_mathemu(struct pt_regs *);
extern int Soft_emulate_8xx(struct pt_regs *);
#if defined(CONFIG_MATH_EMULATION) || defined(CONFIG_8XX_MINIMAL_FPEMU)
int errcode;
#endif
CHECK_FULL_REGS(regs);
......@@ -936,7 +938,7 @@ void SoftwareEmulation(struct pt_regs *regs)
return;
}
#else
#elif defined(CONFIG_8XX_MINIMAL_FPEMU)
errcode = Soft_emulate_8xx(regs);
switch (errcode) {
case 0:
......@@ -949,6 +951,8 @@ void SoftwareEmulation(struct pt_regs *regs)
_exception(SIGSEGV, regs, SEGV_MAPERR, regs->nip);
return;
}
#else
_exception(SIGILL, regs, ILL_ILLOPC, regs->nip);
#endif
}
#endif /* CONFIG_8xx */
......
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