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linux/arch/sparc/mm/fault_32.c

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/*
* 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/perf_event.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;
int show_unhandled_signals = 1;
/* 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(&regs, 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, &regs);
/* Not reached */
return 0;
}
static inline void
show_signal_msg(struct pt_regs *regs, int sig, int code,
unsigned long address, struct task_struct *tsk)
{
if (!unhandled_signal(tsk, sig))
return;
if (!printk_ratelimit())
return;
printk("%s%s[%d]: segfault at %lx ip %p (rpc %p) sp %p error %x",
task_pid_nr(tsk) > 1 ? KERN_INFO : KERN_EMERG,
tsk->comm, task_pid_nr(tsk), address,
(void *)regs->pc, (void *)regs->u_regs[UREG_I7],
(void *)regs->u_regs[UREG_FP], code);
print_vma_addr(KERN_CONT " in ", regs->pc);
printk(KERN_CONT "\n");
}
static void __do_fault_siginfo(int code, int sig, struct pt_regs *regs,
unsigned long addr)
{
siginfo_t info;
info.si_signo = sig;
info.si_code = code;
info.si_errno = 0;
info.si_addr = (void __user *) addr;
info.si_trapno = 0;
if (unlikely(show_unhandled_signals))
show_signal_msg(regs, sig, info.si_code,
addr, current);
force_sig_info (sig, &info, current);
}
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);
}
static noinline void do_fault_siginfo(int code, int sig, struct pt_regs *regs,
int text_fault)
{
unsigned long addr = compute_si_addr(regs, text_fault);
__do_fault_siginfo(code, sig, regs, addr);
}
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;
int from_user = !(regs->psr & PSR_PS);
int fault, code;
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.
*/
code = SEGV_MAPERR;
if (!ARCH_SUN4C && address >= TASK_SIZE)
goto vmalloc_fault;
/*
* If we're in an interrupt or have no user
* context, we must not take the fault..
*/
if (in_atomic() || !mm)
goto no_context;
perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address);
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:
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++;
perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ, 1, regs, address);
} else {
current->min_flt++;
perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN, 1, regs, address);
}
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) {
do_fault_siginfo(code, SIGSEGV, regs, text_fault);
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);
do_fault_siginfo(BUS_ADRERR, SIGBUS, regs, text_fault);
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;
int code;
code = SEGV_MAPERR;
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:
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);
__do_fault_siginfo(code, SIGSEGV, tsk->thread.kregs, address);
return;
do_sigbus:
up_read(&mm->mmap_sem);
__do_fault_siginfo(BUS_ADRERR, SIGBUS, tsk->thread.kregs, address);
}
static void check_stack_aligned(unsigned long sp)
{
if (sp & 0x7UL)
force_sig(SIGILL, current);
}
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);
check_stack_aligned(sp);
}
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);
check_stack_aligned(sp);
}
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);
check_stack_aligned(sp);
}
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