546 lines
14 KiB
C
546 lines
14 KiB
C
/*
|
|
* fault.c: Page fault handlers for the Sparc.
|
|
*
|
|
* Copyright (C) 1995 David S. Miller (davem@caip.rutgers.edu)
|
|
* Copyright (C) 1996 Eddie C. Dost (ecd@skynet.be)
|
|
* Copyright (C) 1997 Jakub Jelinek (jj@sunsite.mff.cuni.cz)
|
|
*/
|
|
|
|
#include <asm/head.h>
|
|
|
|
#include <linux/string.h>
|
|
#include <linux/types.h>
|
|
#include <linux/sched.h>
|
|
#include <linux/ptrace.h>
|
|
#include <linux/mman.h>
|
|
#include <linux/threads.h>
|
|
#include <linux/kernel.h>
|
|
#include <linux/signal.h>
|
|
#include <linux/mm.h>
|
|
#include <linux/smp.h>
|
|
#include <linux/interrupt.h>
|
|
#include <linux/module.h>
|
|
#include <linux/kdebug.h>
|
|
|
|
#include <asm/system.h>
|
|
#include <asm/page.h>
|
|
#include <asm/pgtable.h>
|
|
#include <asm/memreg.h>
|
|
#include <asm/openprom.h>
|
|
#include <asm/oplib.h>
|
|
#include <asm/smp.h>
|
|
#include <asm/traps.h>
|
|
#include <asm/uaccess.h>
|
|
|
|
extern int prom_node_root;
|
|
|
|
/* At boot time we determine these two values necessary for setting
|
|
* up the segment maps and page table entries (pte's).
|
|
*/
|
|
|
|
int num_segmaps, num_contexts;
|
|
int invalid_segment;
|
|
|
|
/* various Virtual Address Cache parameters we find at boot time... */
|
|
|
|
int vac_size, vac_linesize, vac_do_hw_vac_flushes;
|
|
int vac_entries_per_context, vac_entries_per_segment;
|
|
int vac_entries_per_page;
|
|
|
|
/* Return how much physical memory we have. */
|
|
unsigned long probe_memory(void)
|
|
{
|
|
unsigned long total = 0;
|
|
int i;
|
|
|
|
for (i = 0; sp_banks[i].num_bytes; i++)
|
|
total += sp_banks[i].num_bytes;
|
|
|
|
return total;
|
|
}
|
|
|
|
extern void sun4c_complete_all_stores(void);
|
|
|
|
/* Whee, a level 15 NMI interrupt memory error. Let's have fun... */
|
|
asmlinkage void sparc_lvl15_nmi(struct pt_regs *regs, unsigned long serr,
|
|
unsigned long svaddr, unsigned long aerr,
|
|
unsigned long avaddr)
|
|
{
|
|
sun4c_complete_all_stores();
|
|
printk("FAULT: NMI received\n");
|
|
printk("SREGS: Synchronous Error %08lx\n", serr);
|
|
printk(" Synchronous Vaddr %08lx\n", svaddr);
|
|
printk(" Asynchronous Error %08lx\n", aerr);
|
|
printk(" Asynchronous Vaddr %08lx\n", avaddr);
|
|
if (sun4c_memerr_reg)
|
|
printk(" Memory Parity Error %08lx\n", *sun4c_memerr_reg);
|
|
printk("REGISTER DUMP:\n");
|
|
show_regs(regs);
|
|
prom_halt();
|
|
}
|
|
|
|
static void unhandled_fault(unsigned long, struct task_struct *,
|
|
struct pt_regs *) __attribute__ ((noreturn));
|
|
|
|
static void unhandled_fault(unsigned long address, struct task_struct *tsk,
|
|
struct pt_regs *regs)
|
|
{
|
|
if((unsigned long) address < PAGE_SIZE) {
|
|
printk(KERN_ALERT
|
|
"Unable to handle kernel NULL pointer dereference\n");
|
|
} else {
|
|
printk(KERN_ALERT "Unable to handle kernel paging request "
|
|
"at virtual address %08lx\n", address);
|
|
}
|
|
printk(KERN_ALERT "tsk->{mm,active_mm}->context = %08lx\n",
|
|
(tsk->mm ? tsk->mm->context : tsk->active_mm->context));
|
|
printk(KERN_ALERT "tsk->{mm,active_mm}->pgd = %08lx\n",
|
|
(tsk->mm ? (unsigned long) tsk->mm->pgd :
|
|
(unsigned long) tsk->active_mm->pgd));
|
|
die_if_kernel("Oops", regs);
|
|
}
|
|
|
|
asmlinkage int lookup_fault(unsigned long pc, unsigned long ret_pc,
|
|
unsigned long address)
|
|
{
|
|
struct pt_regs regs;
|
|
unsigned long g2;
|
|
unsigned int insn;
|
|
int i;
|
|
|
|
i = search_extables_range(ret_pc, &g2);
|
|
switch (i) {
|
|
case 3:
|
|
/* load & store will be handled by fixup */
|
|
return 3;
|
|
|
|
case 1:
|
|
/* store will be handled by fixup, load will bump out */
|
|
/* for _to_ macros */
|
|
insn = *((unsigned int *) pc);
|
|
if ((insn >> 21) & 1)
|
|
return 1;
|
|
break;
|
|
|
|
case 2:
|
|
/* load will be handled by fixup, store will bump out */
|
|
/* for _from_ macros */
|
|
insn = *((unsigned int *) pc);
|
|
if (!((insn >> 21) & 1) || ((insn>>19)&0x3f) == 15)
|
|
return 2;
|
|
break;
|
|
|
|
default:
|
|
break;
|
|
};
|
|
|
|
memset(®s, 0, sizeof (regs));
|
|
regs.pc = pc;
|
|
regs.npc = pc + 4;
|
|
__asm__ __volatile__(
|
|
"rd %%psr, %0\n\t"
|
|
"nop\n\t"
|
|
"nop\n\t"
|
|
"nop\n" : "=r" (regs.psr));
|
|
unhandled_fault(address, current, ®s);
|
|
|
|
/* Not reached */
|
|
return 0;
|
|
}
|
|
|
|
extern unsigned long safe_compute_effective_address(struct pt_regs *,
|
|
unsigned int);
|
|
|
|
static unsigned long compute_si_addr(struct pt_regs *regs, int text_fault)
|
|
{
|
|
unsigned int insn;
|
|
|
|
if (text_fault)
|
|
return regs->pc;
|
|
|
|
if (regs->psr & PSR_PS) {
|
|
insn = *(unsigned int *) regs->pc;
|
|
} else {
|
|
__get_user(insn, (unsigned int *) regs->pc);
|
|
}
|
|
|
|
return safe_compute_effective_address(regs, insn);
|
|
}
|
|
|
|
asmlinkage void do_sparc_fault(struct pt_regs *regs, int text_fault, int write,
|
|
unsigned long address)
|
|
{
|
|
struct vm_area_struct *vma;
|
|
struct task_struct *tsk = current;
|
|
struct mm_struct *mm = tsk->mm;
|
|
unsigned int fixup;
|
|
unsigned long g2;
|
|
siginfo_t info;
|
|
int from_user = !(regs->psr & PSR_PS);
|
|
int fault;
|
|
|
|
if(text_fault)
|
|
address = regs->pc;
|
|
|
|
/*
|
|
* We fault-in kernel-space virtual memory on-demand. The
|
|
* 'reference' page table is init_mm.pgd.
|
|
*
|
|
* NOTE! We MUST NOT take any locks for this case. We may
|
|
* be in an interrupt or a critical region, and should
|
|
* only copy the information from the master page table,
|
|
* nothing more.
|
|
*/
|
|
if (!ARCH_SUN4C && address >= TASK_SIZE)
|
|
goto vmalloc_fault;
|
|
|
|
info.si_code = SEGV_MAPERR;
|
|
|
|
/*
|
|
* If we're in an interrupt or have no user
|
|
* context, we must not take the fault..
|
|
*/
|
|
if (in_atomic() || !mm)
|
|
goto no_context;
|
|
|
|
down_read(&mm->mmap_sem);
|
|
|
|
/*
|
|
* The kernel referencing a bad kernel pointer can lock up
|
|
* a sun4c machine completely, so we must attempt recovery.
|
|
*/
|
|
if(!from_user && address >= PAGE_OFFSET)
|
|
goto bad_area;
|
|
|
|
vma = find_vma(mm, address);
|
|
if(!vma)
|
|
goto bad_area;
|
|
if(vma->vm_start <= address)
|
|
goto good_area;
|
|
if(!(vma->vm_flags & VM_GROWSDOWN))
|
|
goto bad_area;
|
|
if(expand_stack(vma, address))
|
|
goto bad_area;
|
|
/*
|
|
* Ok, we have a good vm_area for this memory access, so
|
|
* we can handle it..
|
|
*/
|
|
good_area:
|
|
info.si_code = SEGV_ACCERR;
|
|
if(write) {
|
|
if(!(vma->vm_flags & VM_WRITE))
|
|
goto bad_area;
|
|
} else {
|
|
/* Allow reads even for write-only mappings */
|
|
if(!(vma->vm_flags & (VM_READ | VM_EXEC)))
|
|
goto bad_area;
|
|
}
|
|
|
|
/*
|
|
* If for any reason at all we couldn't handle the fault,
|
|
* make sure we exit gracefully rather than endlessly redo
|
|
* the fault.
|
|
*/
|
|
fault = handle_mm_fault(mm, vma, address, write ? FAULT_FLAG_WRITE : 0);
|
|
if (unlikely(fault & VM_FAULT_ERROR)) {
|
|
if (fault & VM_FAULT_OOM)
|
|
goto out_of_memory;
|
|
else if (fault & VM_FAULT_SIGBUS)
|
|
goto do_sigbus;
|
|
BUG();
|
|
}
|
|
if (fault & VM_FAULT_MAJOR)
|
|
current->maj_flt++;
|
|
else
|
|
current->min_flt++;
|
|
up_read(&mm->mmap_sem);
|
|
return;
|
|
|
|
/*
|
|
* Something tried to access memory that isn't in our memory map..
|
|
* Fix it, but check if it's kernel or user first..
|
|
*/
|
|
bad_area:
|
|
up_read(&mm->mmap_sem);
|
|
|
|
bad_area_nosemaphore:
|
|
/* User mode accesses just cause a SIGSEGV */
|
|
if(from_user) {
|
|
#if 0
|
|
printk("Fault whee %s [%d]: segfaults at %08lx pc=%08lx\n",
|
|
tsk->comm, tsk->pid, address, regs->pc);
|
|
#endif
|
|
info.si_signo = SIGSEGV;
|
|
info.si_errno = 0;
|
|
/* info.si_code set above to make clear whether
|
|
this was a SEGV_MAPERR or SEGV_ACCERR fault. */
|
|
info.si_addr = (void __user *)compute_si_addr(regs, text_fault);
|
|
info.si_trapno = 0;
|
|
force_sig_info (SIGSEGV, &info, tsk);
|
|
return;
|
|
}
|
|
|
|
/* Is this in ex_table? */
|
|
no_context:
|
|
g2 = regs->u_regs[UREG_G2];
|
|
if (!from_user) {
|
|
fixup = search_extables_range(regs->pc, &g2);
|
|
if (fixup > 10) { /* Values below are reserved for other things */
|
|
extern const unsigned __memset_start[];
|
|
extern const unsigned __memset_end[];
|
|
extern const unsigned __csum_partial_copy_start[];
|
|
extern const unsigned __csum_partial_copy_end[];
|
|
|
|
#ifdef DEBUG_EXCEPTIONS
|
|
printk("Exception: PC<%08lx> faddr<%08lx>\n", regs->pc, address);
|
|
printk("EX_TABLE: insn<%08lx> fixup<%08x> g2<%08lx>\n",
|
|
regs->pc, fixup, g2);
|
|
#endif
|
|
if ((regs->pc >= (unsigned long)__memset_start &&
|
|
regs->pc < (unsigned long)__memset_end) ||
|
|
(regs->pc >= (unsigned long)__csum_partial_copy_start &&
|
|
regs->pc < (unsigned long)__csum_partial_copy_end)) {
|
|
regs->u_regs[UREG_I4] = address;
|
|
regs->u_regs[UREG_I5] = regs->pc;
|
|
}
|
|
regs->u_regs[UREG_G2] = g2;
|
|
regs->pc = fixup;
|
|
regs->npc = regs->pc + 4;
|
|
return;
|
|
}
|
|
}
|
|
|
|
unhandled_fault (address, tsk, regs);
|
|
do_exit(SIGKILL);
|
|
|
|
/*
|
|
* We ran out of memory, or some other thing happened to us that made
|
|
* us unable to handle the page fault gracefully.
|
|
*/
|
|
out_of_memory:
|
|
up_read(&mm->mmap_sem);
|
|
if (from_user) {
|
|
pagefault_out_of_memory();
|
|
return;
|
|
}
|
|
goto no_context;
|
|
|
|
do_sigbus:
|
|
up_read(&mm->mmap_sem);
|
|
info.si_signo = SIGBUS;
|
|
info.si_errno = 0;
|
|
info.si_code = BUS_ADRERR;
|
|
info.si_addr = (void __user *) compute_si_addr(regs, text_fault);
|
|
info.si_trapno = 0;
|
|
force_sig_info (SIGBUS, &info, tsk);
|
|
if (!from_user)
|
|
goto no_context;
|
|
|
|
vmalloc_fault:
|
|
{
|
|
/*
|
|
* Synchronize this task's top level page-table
|
|
* with the 'reference' page table.
|
|
*/
|
|
int offset = pgd_index(address);
|
|
pgd_t *pgd, *pgd_k;
|
|
pmd_t *pmd, *pmd_k;
|
|
|
|
pgd = tsk->active_mm->pgd + offset;
|
|
pgd_k = init_mm.pgd + offset;
|
|
|
|
if (!pgd_present(*pgd)) {
|
|
if (!pgd_present(*pgd_k))
|
|
goto bad_area_nosemaphore;
|
|
pgd_val(*pgd) = pgd_val(*pgd_k);
|
|
return;
|
|
}
|
|
|
|
pmd = pmd_offset(pgd, address);
|
|
pmd_k = pmd_offset(pgd_k, address);
|
|
|
|
if (pmd_present(*pmd) || !pmd_present(*pmd_k))
|
|
goto bad_area_nosemaphore;
|
|
*pmd = *pmd_k;
|
|
return;
|
|
}
|
|
}
|
|
|
|
asmlinkage void do_sun4c_fault(struct pt_regs *regs, int text_fault, int write,
|
|
unsigned long address)
|
|
{
|
|
extern void sun4c_update_mmu_cache(struct vm_area_struct *,
|
|
unsigned long,pte_t);
|
|
extern pte_t *sun4c_pte_offset_kernel(pmd_t *,unsigned long);
|
|
struct task_struct *tsk = current;
|
|
struct mm_struct *mm = tsk->mm;
|
|
pgd_t *pgdp;
|
|
pte_t *ptep;
|
|
|
|
if (text_fault) {
|
|
address = regs->pc;
|
|
} else if (!write &&
|
|
!(regs->psr & PSR_PS)) {
|
|
unsigned int insn, __user *ip;
|
|
|
|
ip = (unsigned int __user *)regs->pc;
|
|
if (!get_user(insn, ip)) {
|
|
if ((insn & 0xc1680000) == 0xc0680000)
|
|
write = 1;
|
|
}
|
|
}
|
|
|
|
if (!mm) {
|
|
/* We are oopsing. */
|
|
do_sparc_fault(regs, text_fault, write, address);
|
|
BUG(); /* P3 Oops already, you bitch */
|
|
}
|
|
|
|
pgdp = pgd_offset(mm, address);
|
|
ptep = sun4c_pte_offset_kernel((pmd_t *) pgdp, address);
|
|
|
|
if (pgd_val(*pgdp)) {
|
|
if (write) {
|
|
if ((pte_val(*ptep) & (_SUN4C_PAGE_WRITE|_SUN4C_PAGE_PRESENT))
|
|
== (_SUN4C_PAGE_WRITE|_SUN4C_PAGE_PRESENT)) {
|
|
unsigned long flags;
|
|
|
|
*ptep = __pte(pte_val(*ptep) | _SUN4C_PAGE_ACCESSED |
|
|
_SUN4C_PAGE_MODIFIED |
|
|
_SUN4C_PAGE_VALID |
|
|
_SUN4C_PAGE_DIRTY);
|
|
|
|
local_irq_save(flags);
|
|
if (sun4c_get_segmap(address) != invalid_segment) {
|
|
sun4c_put_pte(address, pte_val(*ptep));
|
|
local_irq_restore(flags);
|
|
return;
|
|
}
|
|
local_irq_restore(flags);
|
|
}
|
|
} else {
|
|
if ((pte_val(*ptep) & (_SUN4C_PAGE_READ|_SUN4C_PAGE_PRESENT))
|
|
== (_SUN4C_PAGE_READ|_SUN4C_PAGE_PRESENT)) {
|
|
unsigned long flags;
|
|
|
|
*ptep = __pte(pte_val(*ptep) | _SUN4C_PAGE_ACCESSED |
|
|
_SUN4C_PAGE_VALID);
|
|
|
|
local_irq_save(flags);
|
|
if (sun4c_get_segmap(address) != invalid_segment) {
|
|
sun4c_put_pte(address, pte_val(*ptep));
|
|
local_irq_restore(flags);
|
|
return;
|
|
}
|
|
local_irq_restore(flags);
|
|
}
|
|
}
|
|
}
|
|
|
|
/* This conditional is 'interesting'. */
|
|
if (pgd_val(*pgdp) && !(write && !(pte_val(*ptep) & _SUN4C_PAGE_WRITE))
|
|
&& (pte_val(*ptep) & _SUN4C_PAGE_VALID))
|
|
/* Note: It is safe to not grab the MMAP semaphore here because
|
|
* we know that update_mmu_cache() will not sleep for
|
|
* any reason (at least not in the current implementation)
|
|
* and therefore there is no danger of another thread getting
|
|
* on the CPU and doing a shrink_mmap() on this vma.
|
|
*/
|
|
sun4c_update_mmu_cache (find_vma(current->mm, address), address,
|
|
*ptep);
|
|
else
|
|
do_sparc_fault(regs, text_fault, write, address);
|
|
}
|
|
|
|
/* This always deals with user addresses. */
|
|
static void force_user_fault(unsigned long address, int write)
|
|
{
|
|
struct vm_area_struct *vma;
|
|
struct task_struct *tsk = current;
|
|
struct mm_struct *mm = tsk->mm;
|
|
siginfo_t info;
|
|
|
|
info.si_code = SEGV_MAPERR;
|
|
|
|
#if 0
|
|
printk("wf<pid=%d,wr=%d,addr=%08lx>\n",
|
|
tsk->pid, write, address);
|
|
#endif
|
|
down_read(&mm->mmap_sem);
|
|
vma = find_vma(mm, address);
|
|
if(!vma)
|
|
goto bad_area;
|
|
if(vma->vm_start <= address)
|
|
goto good_area;
|
|
if(!(vma->vm_flags & VM_GROWSDOWN))
|
|
goto bad_area;
|
|
if(expand_stack(vma, address))
|
|
goto bad_area;
|
|
good_area:
|
|
info.si_code = SEGV_ACCERR;
|
|
if(write) {
|
|
if(!(vma->vm_flags & VM_WRITE))
|
|
goto bad_area;
|
|
} else {
|
|
if(!(vma->vm_flags & (VM_READ | VM_EXEC)))
|
|
goto bad_area;
|
|
}
|
|
switch (handle_mm_fault(mm, vma, address, write ? FAULT_FLAG_WRITE : 0)) {
|
|
case VM_FAULT_SIGBUS:
|
|
case VM_FAULT_OOM:
|
|
goto do_sigbus;
|
|
}
|
|
up_read(&mm->mmap_sem);
|
|
return;
|
|
bad_area:
|
|
up_read(&mm->mmap_sem);
|
|
#if 0
|
|
printk("Window whee %s [%d]: segfaults at %08lx\n",
|
|
tsk->comm, tsk->pid, address);
|
|
#endif
|
|
info.si_signo = SIGSEGV;
|
|
info.si_errno = 0;
|
|
/* info.si_code set above to make clear whether
|
|
this was a SEGV_MAPERR or SEGV_ACCERR fault. */
|
|
info.si_addr = (void __user *) address;
|
|
info.si_trapno = 0;
|
|
force_sig_info (SIGSEGV, &info, tsk);
|
|
return;
|
|
|
|
do_sigbus:
|
|
up_read(&mm->mmap_sem);
|
|
info.si_signo = SIGBUS;
|
|
info.si_errno = 0;
|
|
info.si_code = BUS_ADRERR;
|
|
info.si_addr = (void __user *) address;
|
|
info.si_trapno = 0;
|
|
force_sig_info (SIGBUS, &info, tsk);
|
|
}
|
|
|
|
void window_overflow_fault(void)
|
|
{
|
|
unsigned long sp;
|
|
|
|
sp = current_thread_info()->rwbuf_stkptrs[0];
|
|
if(((sp + 0x38) & PAGE_MASK) != (sp & PAGE_MASK))
|
|
force_user_fault(sp + 0x38, 1);
|
|
force_user_fault(sp, 1);
|
|
}
|
|
|
|
void window_underflow_fault(unsigned long sp)
|
|
{
|
|
if(((sp + 0x38) & PAGE_MASK) != (sp & PAGE_MASK))
|
|
force_user_fault(sp + 0x38, 0);
|
|
force_user_fault(sp, 0);
|
|
}
|
|
|
|
void window_ret_fault(struct pt_regs *regs)
|
|
{
|
|
unsigned long sp;
|
|
|
|
sp = regs->u_regs[UREG_FP];
|
|
if(((sp + 0x38) & PAGE_MASK) != (sp & PAGE_MASK))
|
|
force_user_fault(sp + 0x38, 0);
|
|
force_user_fault(sp, 0);
|
|
}
|