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Diffstat (limited to 'arch/sparc/mm/fault_64.c')
-rw-r--r--arch/sparc/mm/fault_64.c532
1 files changed, 532 insertions, 0 deletions
diff --git a/arch/sparc/mm/fault_64.c b/arch/sparc/mm/fault_64.c
new file mode 100644
index 000000000..e326caf70
--- /dev/null
+++ b/arch/sparc/mm/fault_64.c
@@ -0,0 +1,532 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * arch/sparc64/mm/fault.c: Page fault handlers for the 64-bit Sparc.
+ *
+ * Copyright (C) 1996, 2008 David S. Miller (davem@davemloft.net)
+ * Copyright (C) 1997, 1999 Jakub Jelinek (jj@ultra.linux.cz)
+ */
+
+#include <asm/head.h>
+
+#include <linux/string.h>
+#include <linux/types.h>
+#include <linux/sched.h>
+#include <linux/sched/debug.h>
+#include <linux/ptrace.h>
+#include <linux/mman.h>
+#include <linux/signal.h>
+#include <linux/mm.h>
+#include <linux/extable.h>
+#include <linux/init.h>
+#include <linux/perf_event.h>
+#include <linux/interrupt.h>
+#include <linux/kprobes.h>
+#include <linux/kdebug.h>
+#include <linux/percpu.h>
+#include <linux/context_tracking.h>
+#include <linux/uaccess.h>
+
+#include <asm/page.h>
+#include <asm/openprom.h>
+#include <asm/oplib.h>
+#include <asm/asi.h>
+#include <asm/lsu.h>
+#include <asm/sections.h>
+#include <asm/mmu_context.h>
+#include <asm/setup.h>
+
+int show_unhandled_signals = 1;
+
+static void __kprobes 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 %016lx\n", (unsigned long)address);
+ }
+ printk(KERN_ALERT "tsk->{mm,active_mm}->context = %016lx\n",
+ (tsk->mm ?
+ CTX_HWBITS(tsk->mm->context) :
+ CTX_HWBITS(tsk->active_mm->context)));
+ printk(KERN_ALERT "tsk->{mm,active_mm}->pgd = %016lx\n",
+ (tsk->mm ? (unsigned long) tsk->mm->pgd :
+ (unsigned long) tsk->active_mm->pgd));
+ die_if_kernel("Oops", regs);
+}
+
+static void __kprobes bad_kernel_pc(struct pt_regs *regs, unsigned long vaddr)
+{
+ printk(KERN_CRIT "OOPS: Bogus kernel PC [%016lx] in fault handler\n",
+ regs->tpc);
+ printk(KERN_CRIT "OOPS: RPC [%016lx]\n", regs->u_regs[15]);
+ printk("OOPS: RPC <%pS>\n", (void *) regs->u_regs[15]);
+ printk(KERN_CRIT "OOPS: Fault was to vaddr[%lx]\n", vaddr);
+ dump_stack();
+ unhandled_fault(regs->tpc, current, regs);
+}
+
+/*
+ * We now make sure that mmap_lock is held in all paths that call
+ * this. Additionally, to prevent kswapd from ripping ptes from
+ * under us, raise interrupts around the time that we look at the
+ * pte, kswapd will have to wait to get his smp ipi response from
+ * us. vmtruncate likewise. This saves us having to get pte lock.
+ */
+static unsigned int get_user_insn(unsigned long tpc)
+{
+ pgd_t *pgdp = pgd_offset(current->mm, tpc);
+ p4d_t *p4dp;
+ pud_t *pudp;
+ pmd_t *pmdp;
+ pte_t *ptep, pte;
+ unsigned long pa;
+ u32 insn = 0;
+
+ if (pgd_none(*pgdp) || unlikely(pgd_bad(*pgdp)))
+ goto out;
+ p4dp = p4d_offset(pgdp, tpc);
+ if (p4d_none(*p4dp) || unlikely(p4d_bad(*p4dp)))
+ goto out;
+ pudp = pud_offset(p4dp, tpc);
+ if (pud_none(*pudp) || unlikely(pud_bad(*pudp)))
+ goto out;
+
+ /* This disables preemption for us as well. */
+ local_irq_disable();
+
+ pmdp = pmd_offset(pudp, tpc);
+again:
+ if (pmd_none(*pmdp) || unlikely(pmd_bad(*pmdp)))
+ goto out_irq_enable;
+
+#if defined(CONFIG_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE)
+ if (is_hugetlb_pmd(*pmdp)) {
+ pa = pmd_pfn(*pmdp) << PAGE_SHIFT;
+ pa += tpc & ~HPAGE_MASK;
+
+ /* Use phys bypass so we don't pollute dtlb/dcache. */
+ __asm__ __volatile__("lduwa [%1] %2, %0"
+ : "=r" (insn)
+ : "r" (pa), "i" (ASI_PHYS_USE_EC));
+ } else
+#endif
+ {
+ ptep = pte_offset_map(pmdp, tpc);
+ if (!ptep)
+ goto again;
+ pte = *ptep;
+ if (pte_present(pte)) {
+ pa = (pte_pfn(pte) << PAGE_SHIFT);
+ pa += (tpc & ~PAGE_MASK);
+
+ /* Use phys bypass so we don't pollute dtlb/dcache. */
+ __asm__ __volatile__("lduwa [%1] %2, %0"
+ : "=r" (insn)
+ : "r" (pa), "i" (ASI_PHYS_USE_EC));
+ }
+ pte_unmap(ptep);
+ }
+out_irq_enable:
+ local_irq_enable();
+out:
+ return insn;
+}
+
+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 %px (rpc %px) sp %px error %x",
+ task_pid_nr(tsk) > 1 ? KERN_INFO : KERN_EMERG,
+ tsk->comm, task_pid_nr(tsk), address,
+ (void *)regs->tpc, (void *)regs->u_regs[UREG_I7],
+ (void *)regs->u_regs[UREG_FP], code);
+
+ print_vma_addr(KERN_CONT " in ", regs->tpc);
+
+ printk(KERN_CONT "\n");
+}
+
+static void do_fault_siginfo(int code, int sig, struct pt_regs *regs,
+ unsigned long fault_addr, unsigned int insn,
+ int fault_code)
+{
+ unsigned long addr;
+
+ if (fault_code & FAULT_CODE_ITLB) {
+ addr = regs->tpc;
+ } else {
+ /* If we were able to probe the faulting instruction, use it
+ * to compute a precise fault address. Otherwise use the fault
+ * time provided address which may only have page granularity.
+ */
+ if (insn)
+ addr = compute_effective_address(regs, insn, 0);
+ else
+ addr = fault_addr;
+ }
+
+ if (unlikely(show_unhandled_signals))
+ show_signal_msg(regs, sig, code, addr, current);
+
+ force_sig_fault(sig, code, (void __user *) addr);
+}
+
+static unsigned int get_fault_insn(struct pt_regs *regs, unsigned int insn)
+{
+ if (!insn) {
+ if (!regs->tpc || (regs->tpc & 0x3))
+ return 0;
+ if (regs->tstate & TSTATE_PRIV) {
+ insn = *(unsigned int *) regs->tpc;
+ } else {
+ insn = get_user_insn(regs->tpc);
+ }
+ }
+ return insn;
+}
+
+static void __kprobes do_kernel_fault(struct pt_regs *regs, int si_code,
+ int fault_code, unsigned int insn,
+ unsigned long address)
+{
+ unsigned char asi = ASI_P;
+
+ if ((!insn) && (regs->tstate & TSTATE_PRIV))
+ goto cannot_handle;
+
+ /* If user insn could be read (thus insn is zero), that
+ * is fine. We will just gun down the process with a signal
+ * in that case.
+ */
+
+ if (!(fault_code & (FAULT_CODE_WRITE|FAULT_CODE_ITLB)) &&
+ (insn & 0xc0800000) == 0xc0800000) {
+ if (insn & 0x2000)
+ asi = (regs->tstate >> 24);
+ else
+ asi = (insn >> 5);
+ if ((asi & 0xf2) == 0x82) {
+ if (insn & 0x1000000) {
+ handle_ldf_stq(insn, regs);
+ } else {
+ /* This was a non-faulting load. Just clear the
+ * destination register(s) and continue with the next
+ * instruction. -jj
+ */
+ handle_ld_nf(insn, regs);
+ }
+ return;
+ }
+ }
+
+ /* Is this in ex_table? */
+ if (regs->tstate & TSTATE_PRIV) {
+ const struct exception_table_entry *entry;
+
+ entry = search_exception_tables(regs->tpc);
+ if (entry) {
+ regs->tpc = entry->fixup;
+ regs->tnpc = regs->tpc + 4;
+ return;
+ }
+ } else {
+ /* The si_code was set to make clear whether
+ * this was a SEGV_MAPERR or SEGV_ACCERR fault.
+ */
+ do_fault_siginfo(si_code, SIGSEGV, regs, address, insn, fault_code);
+ return;
+ }
+
+cannot_handle:
+ unhandled_fault (address, current, regs);
+}
+
+static void noinline __kprobes bogus_32bit_fault_tpc(struct pt_regs *regs)
+{
+ static int times;
+
+ if (times++ < 10)
+ printk(KERN_ERR "FAULT[%s:%d]: 32-bit process reports "
+ "64-bit TPC [%lx]\n",
+ current->comm, current->pid,
+ regs->tpc);
+ show_regs(regs);
+}
+
+asmlinkage void __kprobes do_sparc64_fault(struct pt_regs *regs)
+{
+ enum ctx_state prev_state = exception_enter();
+ struct mm_struct *mm = current->mm;
+ struct vm_area_struct *vma;
+ unsigned int insn = 0;
+ int si_code, fault_code;
+ vm_fault_t fault;
+ unsigned long address, mm_rss;
+ unsigned int flags = FAULT_FLAG_DEFAULT;
+
+ fault_code = get_thread_fault_code();
+
+ if (kprobe_page_fault(regs, 0))
+ goto exit_exception;
+
+ si_code = SEGV_MAPERR;
+ address = current_thread_info()->fault_address;
+
+ if ((fault_code & FAULT_CODE_ITLB) &&
+ (fault_code & FAULT_CODE_DTLB))
+ BUG();
+
+ if (test_thread_flag(TIF_32BIT)) {
+ if (!(regs->tstate & TSTATE_PRIV)) {
+ if (unlikely((regs->tpc >> 32) != 0)) {
+ bogus_32bit_fault_tpc(regs);
+ goto intr_or_no_mm;
+ }
+ }
+ if (unlikely((address >> 32) != 0))
+ goto intr_or_no_mm;
+ }
+
+ if (regs->tstate & TSTATE_PRIV) {
+ unsigned long tpc = regs->tpc;
+
+ /* Sanity check the PC. */
+ if ((tpc >= KERNBASE && tpc < (unsigned long) __init_end) ||
+ (tpc >= MODULES_VADDR && tpc < MODULES_END)) {
+ /* Valid, no problems... */
+ } else {
+ bad_kernel_pc(regs, address);
+ goto exit_exception;
+ }
+ } else
+ flags |= FAULT_FLAG_USER;
+
+ /*
+ * If we're in an interrupt or have no user
+ * context, we must not take the fault..
+ */
+ if (faulthandler_disabled() || !mm)
+ goto intr_or_no_mm;
+
+ perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address);
+
+ if (!mmap_read_trylock(mm)) {
+ if ((regs->tstate & TSTATE_PRIV) &&
+ !search_exception_tables(regs->tpc)) {
+ insn = get_fault_insn(regs, insn);
+ goto handle_kernel_fault;
+ }
+
+retry:
+ mmap_read_lock(mm);
+ }
+
+ if (fault_code & FAULT_CODE_BAD_RA)
+ goto do_sigbus;
+
+ vma = find_vma(mm, address);
+ if (!vma)
+ goto bad_area;
+
+ /* Pure DTLB misses do not tell us whether the fault causing
+ * load/store/atomic was a write or not, it only says that there
+ * was no match. So in such a case we (carefully) read the
+ * instruction to try and figure this out. It's an optimization
+ * so it's ok if we can't do this.
+ *
+ * Special hack, window spill/fill knows the exact fault type.
+ */
+ if (((fault_code &
+ (FAULT_CODE_DTLB | FAULT_CODE_WRITE | FAULT_CODE_WINFIXUP)) == FAULT_CODE_DTLB) &&
+ (vma->vm_flags & VM_WRITE) != 0) {
+ insn = get_fault_insn(regs, 0);
+ if (!insn)
+ goto continue_fault;
+ /* All loads, stores and atomics have bits 30 and 31 both set
+ * in the instruction. Bit 21 is set in all stores, but we
+ * have to avoid prefetches which also have bit 21 set.
+ */
+ if ((insn & 0xc0200000) == 0xc0200000 &&
+ (insn & 0x01780000) != 0x01680000) {
+ /* Don't bother updating thread struct value,
+ * because update_mmu_cache only cares which tlb
+ * the access came from.
+ */
+ fault_code |= FAULT_CODE_WRITE;
+ }
+ }
+continue_fault:
+
+ if (vma->vm_start <= address)
+ goto good_area;
+ if (!(vma->vm_flags & VM_GROWSDOWN))
+ goto bad_area;
+ if (!(fault_code & FAULT_CODE_WRITE)) {
+ /* Non-faulting loads shouldn't expand stack. */
+ insn = get_fault_insn(regs, insn);
+ if ((insn & 0xc0800000) == 0xc0800000) {
+ unsigned char asi;
+
+ if (insn & 0x2000)
+ asi = (regs->tstate >> 24);
+ else
+ asi = (insn >> 5);
+ if ((asi & 0xf2) == 0x82)
+ goto bad_area;
+ }
+ }
+ vma = expand_stack(mm, address);
+ if (!vma)
+ goto bad_area_nosemaphore;
+ /*
+ * Ok, we have a good vm_area for this memory access, so
+ * we can handle it..
+ */
+good_area:
+ si_code = SEGV_ACCERR;
+
+ /* If we took a ITLB miss on a non-executable page, catch
+ * that here.
+ */
+ if ((fault_code & FAULT_CODE_ITLB) && !(vma->vm_flags & VM_EXEC)) {
+ WARN(address != regs->tpc,
+ "address (%lx) != regs->tpc (%lx)\n", address, regs->tpc);
+ WARN_ON(regs->tstate & TSTATE_PRIV);
+ goto bad_area;
+ }
+
+ if (fault_code & FAULT_CODE_WRITE) {
+ if (!(vma->vm_flags & VM_WRITE))
+ goto bad_area;
+
+ /* Spitfire has an icache which does not snoop
+ * processor stores. Later processors do...
+ */
+ if (tlb_type == spitfire &&
+ (vma->vm_flags & VM_EXEC) != 0 &&
+ vma->vm_file != NULL)
+ set_thread_fault_code(fault_code |
+ FAULT_CODE_BLKCOMMIT);
+
+ flags |= FAULT_FLAG_WRITE;
+ } else {
+ /* Allow reads even for write-only mappings */
+ if (!(vma->vm_flags & (VM_READ | VM_EXEC)))
+ goto bad_area;
+ }
+
+ fault = handle_mm_fault(vma, address, flags, regs);
+
+ if (fault_signal_pending(fault, regs)) {
+ if (regs->tstate & TSTATE_PRIV) {
+ insn = get_fault_insn(regs, insn);
+ goto handle_kernel_fault;
+ }
+ goto exit_exception;
+ }
+
+ /* The fault is fully completed (including releasing mmap lock) */
+ if (fault & VM_FAULT_COMPLETED)
+ goto lock_released;
+
+ if (unlikely(fault & VM_FAULT_ERROR)) {
+ if (fault & VM_FAULT_OOM)
+ goto out_of_memory;
+ else if (fault & VM_FAULT_SIGSEGV)
+ goto bad_area;
+ else if (fault & VM_FAULT_SIGBUS)
+ goto do_sigbus;
+ BUG();
+ }
+
+ if (fault & VM_FAULT_RETRY) {
+ flags |= FAULT_FLAG_TRIED;
+
+ /* No need to mmap_read_unlock(mm) as we would
+ * have already released it in __lock_page_or_retry
+ * in mm/filemap.c.
+ */
+
+ goto retry;
+ }
+ mmap_read_unlock(mm);
+
+lock_released:
+ mm_rss = get_mm_rss(mm);
+#if defined(CONFIG_TRANSPARENT_HUGEPAGE)
+ mm_rss -= (mm->context.thp_pte_count * (HPAGE_SIZE / PAGE_SIZE));
+#endif
+ if (unlikely(mm_rss >
+ mm->context.tsb_block[MM_TSB_BASE].tsb_rss_limit))
+ tsb_grow(mm, MM_TSB_BASE, mm_rss);
+#if defined(CONFIG_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE)
+ mm_rss = mm->context.hugetlb_pte_count + mm->context.thp_pte_count;
+ mm_rss *= REAL_HPAGE_PER_HPAGE;
+ if (unlikely(mm_rss >
+ mm->context.tsb_block[MM_TSB_HUGE].tsb_rss_limit)) {
+ if (mm->context.tsb_block[MM_TSB_HUGE].tsb)
+ tsb_grow(mm, MM_TSB_HUGE, mm_rss);
+ else
+ hugetlb_setup(regs);
+
+ }
+#endif
+exit_exception:
+ exception_exit(prev_state);
+ 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:
+ mmap_read_unlock(mm);
+bad_area_nosemaphore:
+ insn = get_fault_insn(regs, insn);
+
+handle_kernel_fault:
+ do_kernel_fault(regs, si_code, fault_code, insn, address);
+ goto exit_exception;
+
+/*
+ * 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:
+ insn = get_fault_insn(regs, insn);
+ mmap_read_unlock(mm);
+ if (!(regs->tstate & TSTATE_PRIV)) {
+ pagefault_out_of_memory();
+ goto exit_exception;
+ }
+ goto handle_kernel_fault;
+
+intr_or_no_mm:
+ insn = get_fault_insn(regs, 0);
+ goto handle_kernel_fault;
+
+do_sigbus:
+ insn = get_fault_insn(regs, insn);
+ mmap_read_unlock(mm);
+
+ /*
+ * Send a sigbus, regardless of whether we were in kernel
+ * or user mode.
+ */
+ do_fault_siginfo(BUS_ADRERR, SIGBUS, regs, address, insn, fault_code);
+
+ /* Kernel mode? Handle exceptions or die */
+ if (regs->tstate & TSTATE_PRIV)
+ goto handle_kernel_fault;
+}
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