8cf14af0a7
The funny "range" exception table entries we had were only used by the compat layer socketcall assembly, and it wasn't even needed there. For free we now get proper exception table sorting and fast binary searching. Signed-off-by: David S. Miller <davem@davemloft.net>
510 lines
13 KiB
C
510 lines
13 KiB
C
/* $Id: fault.c,v 1.59 2002/02/09 19:49:31 davem Exp $
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* arch/sparc64/mm/fault.c: Page fault handlers for the 64-bit Sparc.
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*
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* Copyright (C) 1996 David S. Miller (davem@caip.rutgers.edu)
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* Copyright (C) 1997, 1999 Jakub Jelinek (jj@ultra.linux.cz)
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*/
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#include <asm/head.h>
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#include <linux/string.h>
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#include <linux/types.h>
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#include <linux/sched.h>
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#include <linux/ptrace.h>
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#include <linux/mman.h>
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#include <linux/signal.h>
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#include <linux/mm.h>
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#include <linux/module.h>
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#include <linux/smp_lock.h>
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#include <linux/init.h>
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#include <linux/interrupt.h>
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#include <linux/kprobes.h>
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#include <asm/page.h>
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#include <asm/pgtable.h>
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#include <asm/openprom.h>
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#include <asm/oplib.h>
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#include <asm/uaccess.h>
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#include <asm/asi.h>
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#include <asm/lsu.h>
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#include <asm/sections.h>
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#include <asm/kdebug.h>
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#define ELEMENTS(arr) (sizeof (arr)/sizeof (arr[0]))
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extern struct sparc_phys_banks sp_banks[SPARC_PHYS_BANKS];
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/*
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* To debug kernel to catch accesses to certain virtual/physical addresses.
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* Mode = 0 selects physical watchpoints, mode = 1 selects virtual watchpoints.
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* flags = VM_READ watches memread accesses, flags = VM_WRITE watches memwrite accesses.
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* Caller passes in a 64bit aligned addr, with mask set to the bytes that need to be
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* watched. This is only useful on a single cpu machine for now. After the watchpoint
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* is detected, the process causing it will be killed, thus preventing an infinite loop.
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*/
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void set_brkpt(unsigned long addr, unsigned char mask, int flags, int mode)
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{
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unsigned long lsubits;
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__asm__ __volatile__("ldxa [%%g0] %1, %0"
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: "=r" (lsubits)
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: "i" (ASI_LSU_CONTROL));
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lsubits &= ~(LSU_CONTROL_PM | LSU_CONTROL_VM |
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LSU_CONTROL_PR | LSU_CONTROL_VR |
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LSU_CONTROL_PW | LSU_CONTROL_VW);
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__asm__ __volatile__("stxa %0, [%1] %2\n\t"
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"membar #Sync"
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: /* no outputs */
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: "r" (addr), "r" (mode ? VIRT_WATCHPOINT : PHYS_WATCHPOINT),
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"i" (ASI_DMMU));
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lsubits |= ((unsigned long)mask << (mode ? 25 : 33));
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if (flags & VM_READ)
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lsubits |= (mode ? LSU_CONTROL_VR : LSU_CONTROL_PR);
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if (flags & VM_WRITE)
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lsubits |= (mode ? LSU_CONTROL_VW : LSU_CONTROL_PW);
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__asm__ __volatile__("stxa %0, [%%g0] %1\n\t"
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"membar #Sync"
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: /* no outputs */
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: "r" (lsubits), "i" (ASI_LSU_CONTROL)
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: "memory");
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}
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/* Nice, simple, prom library does all the sweating for us. ;) */
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unsigned long __init prom_probe_memory (void)
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{
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register struct linux_mlist_p1275 *mlist;
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register unsigned long bytes, base_paddr, tally;
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register int i;
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i = 0;
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mlist = *prom_meminfo()->p1275_available;
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bytes = tally = mlist->num_bytes;
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base_paddr = mlist->start_adr;
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sp_banks[0].base_addr = base_paddr;
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sp_banks[0].num_bytes = bytes;
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while (mlist->theres_more != (void *) 0) {
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i++;
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mlist = mlist->theres_more;
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bytes = mlist->num_bytes;
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tally += bytes;
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if (i >= SPARC_PHYS_BANKS-1) {
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printk ("The machine has more banks than "
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"this kernel can support\n"
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"Increase the SPARC_PHYS_BANKS "
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"setting (currently %d)\n",
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SPARC_PHYS_BANKS);
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i = SPARC_PHYS_BANKS-1;
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break;
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}
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sp_banks[i].base_addr = mlist->start_adr;
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sp_banks[i].num_bytes = mlist->num_bytes;
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}
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i++;
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sp_banks[i].base_addr = 0xdeadbeefbeefdeadUL;
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sp_banks[i].num_bytes = 0;
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/* Now mask all bank sizes on a page boundary, it is all we can
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* use anyways.
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*/
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for (i = 0; sp_banks[i].num_bytes != 0; i++)
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sp_banks[i].num_bytes &= PAGE_MASK;
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return tally;
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}
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static void __kprobes unhandled_fault(unsigned long address,
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struct task_struct *tsk,
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struct pt_regs *regs)
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{
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if ((unsigned long) address < PAGE_SIZE) {
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printk(KERN_ALERT "Unable to handle kernel NULL "
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"pointer dereference\n");
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} else {
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printk(KERN_ALERT "Unable to handle kernel paging request "
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"at virtual address %016lx\n", (unsigned long)address);
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}
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printk(KERN_ALERT "tsk->{mm,active_mm}->context = %016lx\n",
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(tsk->mm ?
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CTX_HWBITS(tsk->mm->context) :
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CTX_HWBITS(tsk->active_mm->context)));
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printk(KERN_ALERT "tsk->{mm,active_mm}->pgd = %016lx\n",
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(tsk->mm ? (unsigned long) tsk->mm->pgd :
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(unsigned long) tsk->active_mm->pgd));
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if (notify_die(DIE_GPF, "general protection fault", regs,
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0, 0, SIGSEGV) == NOTIFY_STOP)
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return;
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die_if_kernel("Oops", regs);
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}
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static void bad_kernel_pc(struct pt_regs *regs)
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{
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unsigned long *ksp;
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printk(KERN_CRIT "OOPS: Bogus kernel PC [%016lx] in fault handler\n",
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regs->tpc);
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__asm__("mov %%sp, %0" : "=r" (ksp));
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show_stack(current, ksp);
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unhandled_fault(regs->tpc, current, regs);
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}
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/*
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* We now make sure that mmap_sem is held in all paths that call
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* this. Additionally, to prevent kswapd from ripping ptes from
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* under us, raise interrupts around the time that we look at the
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* pte, kswapd will have to wait to get his smp ipi response from
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* us. This saves us having to get page_table_lock.
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*/
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static unsigned int get_user_insn(unsigned long tpc)
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{
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pgd_t *pgdp = pgd_offset(current->mm, tpc);
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pud_t *pudp;
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pmd_t *pmdp;
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pte_t *ptep, pte;
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unsigned long pa;
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u32 insn = 0;
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unsigned long pstate;
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if (pgd_none(*pgdp))
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goto outret;
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pudp = pud_offset(pgdp, tpc);
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if (pud_none(*pudp))
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goto outret;
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pmdp = pmd_offset(pudp, tpc);
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if (pmd_none(*pmdp))
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goto outret;
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/* This disables preemption for us as well. */
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__asm__ __volatile__("rdpr %%pstate, %0" : "=r" (pstate));
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__asm__ __volatile__("wrpr %0, %1, %%pstate"
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: : "r" (pstate), "i" (PSTATE_IE));
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ptep = pte_offset_map(pmdp, tpc);
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pte = *ptep;
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if (!pte_present(pte))
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goto out;
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pa = (pte_val(pte) & _PAGE_PADDR);
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pa += (tpc & ~PAGE_MASK);
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/* Use phys bypass so we don't pollute dtlb/dcache. */
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__asm__ __volatile__("lduwa [%1] %2, %0"
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: "=r" (insn)
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: "r" (pa), "i" (ASI_PHYS_USE_EC));
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out:
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pte_unmap(ptep);
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__asm__ __volatile__("wrpr %0, 0x0, %%pstate" : : "r" (pstate));
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outret:
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return insn;
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}
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extern unsigned long compute_effective_address(struct pt_regs *, unsigned int, unsigned int);
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static void do_fault_siginfo(int code, int sig, struct pt_regs *regs,
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unsigned int insn, int fault_code)
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{
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siginfo_t info;
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info.si_code = code;
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info.si_signo = sig;
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info.si_errno = 0;
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if (fault_code & FAULT_CODE_ITLB)
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info.si_addr = (void __user *) regs->tpc;
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else
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info.si_addr = (void __user *)
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compute_effective_address(regs, insn, 0);
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info.si_trapno = 0;
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force_sig_info(sig, &info, current);
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}
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extern int handle_ldf_stq(u32, struct pt_regs *);
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extern int handle_ld_nf(u32, struct pt_regs *);
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static unsigned int get_fault_insn(struct pt_regs *regs, unsigned int insn)
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{
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if (!insn) {
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if (!regs->tpc || (regs->tpc & 0x3))
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return 0;
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if (regs->tstate & TSTATE_PRIV) {
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insn = *(unsigned int *) regs->tpc;
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} else {
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insn = get_user_insn(regs->tpc);
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}
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}
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return insn;
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}
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static void do_kernel_fault(struct pt_regs *regs, int si_code, int fault_code,
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unsigned int insn, unsigned long address)
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{
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unsigned char asi = ASI_P;
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if ((!insn) && (regs->tstate & TSTATE_PRIV))
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goto cannot_handle;
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/* If user insn could be read (thus insn is zero), that
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* is fine. We will just gun down the process with a signal
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* in that case.
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*/
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if (!(fault_code & (FAULT_CODE_WRITE|FAULT_CODE_ITLB)) &&
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(insn & 0xc0800000) == 0xc0800000) {
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if (insn & 0x2000)
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asi = (regs->tstate >> 24);
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else
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asi = (insn >> 5);
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if ((asi & 0xf2) == 0x82) {
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if (insn & 0x1000000) {
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handle_ldf_stq(insn, regs);
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} else {
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/* This was a non-faulting load. Just clear the
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* destination register(s) and continue with the next
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* instruction. -jj
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*/
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handle_ld_nf(insn, regs);
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}
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return;
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}
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}
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/* Is this in ex_table? */
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if (regs->tstate & TSTATE_PRIV) {
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const struct exception_table_entry *entry;
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if (asi == ASI_P && (insn & 0xc0800000) == 0xc0800000) {
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if (insn & 0x2000)
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asi = (regs->tstate >> 24);
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else
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asi = (insn >> 5);
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}
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/* Look in asi.h: All _S asis have LS bit set */
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if ((asi & 0x1) &&
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(entry = search_exception_tables(regs->tpc))) {
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regs->tpc = entry->fixup;
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regs->tnpc = regs->tpc + 4;
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return;
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}
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} else {
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/* The si_code was set to make clear whether
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* this was a SEGV_MAPERR or SEGV_ACCERR fault.
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*/
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do_fault_siginfo(si_code, SIGSEGV, regs, insn, fault_code);
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return;
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}
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cannot_handle:
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unhandled_fault (address, current, regs);
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}
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asmlinkage void __kprobes do_sparc64_fault(struct pt_regs *regs)
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{
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struct mm_struct *mm = current->mm;
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struct vm_area_struct *vma;
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unsigned int insn = 0;
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int si_code, fault_code;
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unsigned long address;
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fault_code = get_thread_fault_code();
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if (notify_die(DIE_PAGE_FAULT, "page_fault", regs,
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fault_code, 0, SIGSEGV) == NOTIFY_STOP)
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return;
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si_code = SEGV_MAPERR;
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address = current_thread_info()->fault_address;
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if ((fault_code & FAULT_CODE_ITLB) &&
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(fault_code & FAULT_CODE_DTLB))
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BUG();
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if (regs->tstate & TSTATE_PRIV) {
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unsigned long tpc = regs->tpc;
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/* Sanity check the PC. */
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if ((tpc >= KERNBASE && tpc < (unsigned long) _etext) ||
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(tpc >= MODULES_VADDR && tpc < MODULES_END)) {
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/* Valid, no problems... */
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} else {
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bad_kernel_pc(regs);
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return;
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}
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}
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/*
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* If we're in an interrupt or have no user
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* context, we must not take the fault..
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*/
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if (in_atomic() || !mm)
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goto intr_or_no_mm;
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if (test_thread_flag(TIF_32BIT)) {
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if (!(regs->tstate & TSTATE_PRIV))
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regs->tpc &= 0xffffffff;
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address &= 0xffffffff;
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}
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if (!down_read_trylock(&mm->mmap_sem)) {
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if ((regs->tstate & TSTATE_PRIV) &&
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!search_exception_tables(regs->tpc)) {
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insn = get_fault_insn(regs, insn);
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goto handle_kernel_fault;
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}
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down_read(&mm->mmap_sem);
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}
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vma = find_vma(mm, address);
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if (!vma)
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goto bad_area;
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/* Pure DTLB misses do not tell us whether the fault causing
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* load/store/atomic was a write or not, it only says that there
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* was no match. So in such a case we (carefully) read the
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* instruction to try and figure this out. It's an optimization
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* so it's ok if we can't do this.
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*
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* Special hack, window spill/fill knows the exact fault type.
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*/
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if (((fault_code &
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(FAULT_CODE_DTLB | FAULT_CODE_WRITE | FAULT_CODE_WINFIXUP)) == FAULT_CODE_DTLB) &&
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(vma->vm_flags & VM_WRITE) != 0) {
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insn = get_fault_insn(regs, 0);
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if (!insn)
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goto continue_fault;
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if ((insn & 0xc0200000) == 0xc0200000 &&
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(insn & 0x1780000) != 0x1680000) {
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/* Don't bother updating thread struct value,
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* because update_mmu_cache only cares which tlb
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* the access came from.
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*/
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fault_code |= FAULT_CODE_WRITE;
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}
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}
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continue_fault:
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if (vma->vm_start <= address)
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goto good_area;
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if (!(vma->vm_flags & VM_GROWSDOWN))
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goto bad_area;
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if (!(fault_code & FAULT_CODE_WRITE)) {
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/* Non-faulting loads shouldn't expand stack. */
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insn = get_fault_insn(regs, insn);
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if ((insn & 0xc0800000) == 0xc0800000) {
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unsigned char asi;
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if (insn & 0x2000)
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asi = (regs->tstate >> 24);
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else
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asi = (insn >> 5);
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if ((asi & 0xf2) == 0x82)
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goto bad_area;
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}
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}
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if (expand_stack(vma, address))
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goto bad_area;
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/*
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* Ok, we have a good vm_area for this memory access, so
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* we can handle it..
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*/
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good_area:
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si_code = SEGV_ACCERR;
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/* If we took a ITLB miss on a non-executable page, catch
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* that here.
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*/
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if ((fault_code & FAULT_CODE_ITLB) && !(vma->vm_flags & VM_EXEC)) {
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BUG_ON(address != regs->tpc);
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BUG_ON(regs->tstate & TSTATE_PRIV);
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goto bad_area;
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}
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if (fault_code & FAULT_CODE_WRITE) {
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if (!(vma->vm_flags & VM_WRITE))
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goto bad_area;
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/* Spitfire has an icache which does not snoop
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* processor stores. Later processors do...
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*/
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if (tlb_type == spitfire &&
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(vma->vm_flags & VM_EXEC) != 0 &&
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vma->vm_file != NULL)
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set_thread_fault_code(fault_code |
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FAULT_CODE_BLKCOMMIT);
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} else {
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/* Allow reads even for write-only mappings */
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if (!(vma->vm_flags & (VM_READ | VM_EXEC)))
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goto bad_area;
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}
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switch (handle_mm_fault(mm, vma, address, (fault_code & FAULT_CODE_WRITE))) {
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case VM_FAULT_MINOR:
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current->min_flt++;
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break;
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case VM_FAULT_MAJOR:
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current->maj_flt++;
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break;
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case VM_FAULT_SIGBUS:
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goto do_sigbus;
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case VM_FAULT_OOM:
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goto out_of_memory;
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default:
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BUG();
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}
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up_read(&mm->mmap_sem);
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goto fault_done;
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/*
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* Something tried to access memory that isn't in our memory map..
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* Fix it, but check if it's kernel or user first..
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*/
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bad_area:
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insn = get_fault_insn(regs, insn);
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up_read(&mm->mmap_sem);
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handle_kernel_fault:
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do_kernel_fault(regs, si_code, fault_code, insn, address);
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goto fault_done;
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/*
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* We ran out of memory, or some other thing happened to us that made
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* us unable to handle the page fault gracefully.
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*/
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out_of_memory:
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insn = get_fault_insn(regs, insn);
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up_read(&mm->mmap_sem);
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printk("VM: killing process %s\n", current->comm);
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if (!(regs->tstate & TSTATE_PRIV))
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do_exit(SIGKILL);
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goto handle_kernel_fault;
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intr_or_no_mm:
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insn = get_fault_insn(regs, 0);
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goto handle_kernel_fault;
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do_sigbus:
|
|
insn = get_fault_insn(regs, insn);
|
|
up_read(&mm->mmap_sem);
|
|
|
|
/*
|
|
* Send a sigbus, regardless of whether we were in kernel
|
|
* or user mode.
|
|
*/
|
|
do_fault_siginfo(BUS_ADRERR, SIGBUS, regs, insn, fault_code);
|
|
|
|
/* Kernel mode? Handle exceptions or die */
|
|
if (regs->tstate & TSTATE_PRIV)
|
|
goto handle_kernel_fault;
|
|
|
|
fault_done:
|
|
/* These values are no longer needed, clear them. */
|
|
set_thread_fault_code(0);
|
|
current_thread_info()->fault_address = 0;
|
|
}
|