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-rw-r--r--arch/parisc/mm/fault.c515
1 files changed, 515 insertions, 0 deletions
diff --git a/arch/parisc/mm/fault.c b/arch/parisc/mm/fault.c
new file mode 100644
index 000000000..5faa3cff4
--- /dev/null
+++ b/arch/parisc/mm/fault.c
@@ -0,0 +1,515 @@
+/*
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License. See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ *
+ * Copyright (C) 1995, 1996, 1997, 1998 by Ralf Baechle
+ * Copyright 1999 SuSE GmbH (Philipp Rumpf, prumpf@tux.org)
+ * Copyright 1999 Hewlett Packard Co.
+ *
+ */
+
+#include <linux/mm.h>
+#include <linux/ptrace.h>
+#include <linux/sched.h>
+#include <linux/sched/debug.h>
+#include <linux/interrupt.h>
+#include <linux/extable.h>
+#include <linux/uaccess.h>
+#include <linux/hugetlb.h>
+#include <linux/perf_event.h>
+
+#include <asm/traps.h>
+
+/* Various important other fields */
+#define bit22set(x) (x & 0x00000200)
+#define bits23_25set(x) (x & 0x000001c0)
+#define isGraphicsFlushRead(x) ((x & 0xfc003fdf) == 0x04001a80)
+ /* extended opcode is 0x6a */
+
+#define BITSSET 0x1c0 /* for identifying LDCW */
+
+
+int show_unhandled_signals = 1;
+
+/*
+ * parisc_acctyp(unsigned int inst) --
+ * Given a PA-RISC memory access instruction, determine if the
+ * the instruction would perform a memory read or memory write
+ * operation.
+ *
+ * This function assumes that the given instruction is a memory access
+ * instruction (i.e. you should really only call it if you know that
+ * the instruction has generated some sort of a memory access fault).
+ *
+ * Returns:
+ * VM_READ if read operation
+ * VM_WRITE if write operation
+ * VM_EXEC if execute operation
+ */
+static unsigned long
+parisc_acctyp(unsigned long code, unsigned int inst)
+{
+ if (code == 6 || code == 16)
+ return VM_EXEC;
+
+ switch (inst & 0xf0000000) {
+ case 0x40000000: /* load */
+ case 0x50000000: /* new load */
+ return VM_READ;
+
+ case 0x60000000: /* store */
+ case 0x70000000: /* new store */
+ return VM_WRITE;
+
+ case 0x20000000: /* coproc */
+ case 0x30000000: /* coproc2 */
+ if (bit22set(inst))
+ return VM_WRITE;
+ fallthrough;
+
+ case 0x0: /* indexed/memory management */
+ if (bit22set(inst)) {
+ /*
+ * Check for the 'Graphics Flush Read' instruction.
+ * It resembles an FDC instruction, except for bits
+ * 20 and 21. Any combination other than zero will
+ * utilize the block mover functionality on some
+ * older PA-RISC platforms. The case where a block
+ * move is performed from VM to graphics IO space
+ * should be treated as a READ.
+ *
+ * The significance of bits 20,21 in the FDC
+ * instruction is:
+ *
+ * 00 Flush data cache (normal instruction behavior)
+ * 01 Graphics flush write (IO space -> VM)
+ * 10 Graphics flush read (VM -> IO space)
+ * 11 Graphics flush read/write (VM <-> IO space)
+ */
+ if (isGraphicsFlushRead(inst))
+ return VM_READ;
+ return VM_WRITE;
+ } else {
+ /*
+ * Check for LDCWX and LDCWS (semaphore instructions).
+ * If bits 23 through 25 are all 1's it is one of
+ * the above two instructions and is a write.
+ *
+ * Note: With the limited bits we are looking at,
+ * this will also catch PROBEW and PROBEWI. However,
+ * these should never get in here because they don't
+ * generate exceptions of the type:
+ * Data TLB miss fault/data page fault
+ * Data memory protection trap
+ */
+ if (bits23_25set(inst) == BITSSET)
+ return VM_WRITE;
+ }
+ return VM_READ; /* Default */
+ }
+ return VM_READ; /* Default */
+}
+
+#undef bit22set
+#undef bits23_25set
+#undef isGraphicsFlushRead
+#undef BITSSET
+
+
+#if 0
+/* This is the treewalk to find a vma which is the highest that has
+ * a start < addr. We're using find_vma_prev instead right now, but
+ * we might want to use this at some point in the future. Probably
+ * not, but I want it committed to CVS so I don't lose it :-)
+ */
+ while (tree != vm_avl_empty) {
+ if (tree->vm_start > addr) {
+ tree = tree->vm_avl_left;
+ } else {
+ prev = tree;
+ if (prev->vm_next == NULL)
+ break;
+ if (prev->vm_next->vm_start > addr)
+ break;
+ tree = tree->vm_avl_right;
+ }
+ }
+#endif
+
+int fixup_exception(struct pt_regs *regs)
+{
+ const struct exception_table_entry *fix;
+
+ fix = search_exception_tables(regs->iaoq[0]);
+ if (fix) {
+ /*
+ * Fix up get_user() and put_user().
+ * ASM_EXCEPTIONTABLE_ENTRY_EFAULT() sets the least-significant
+ * bit in the relative address of the fixup routine to indicate
+ * that %r8 should be loaded with -EFAULT to report a userspace
+ * access error.
+ */
+ if (fix->fixup & 1) {
+ regs->gr[8] = -EFAULT;
+
+ /* zero target register for get_user() */
+ if (parisc_acctyp(0, regs->iir) == VM_READ) {
+ int treg = regs->iir & 0x1f;
+ BUG_ON(treg == 0);
+ regs->gr[treg] = 0;
+ }
+ }
+
+ regs->iaoq[0] = (unsigned long)&fix->fixup + fix->fixup;
+ regs->iaoq[0] &= ~3;
+ /*
+ * NOTE: In some cases the faulting instruction
+ * may be in the delay slot of a branch. We
+ * don't want to take the branch, so we don't
+ * increment iaoq[1], instead we set it to be
+ * iaoq[0]+4, and clear the B bit in the PSW
+ */
+ regs->iaoq[1] = regs->iaoq[0] + 4;
+ regs->gr[0] &= ~PSW_B; /* IPSW in gr[0] */
+
+ return 1;
+ }
+
+ return 0;
+}
+
+/*
+ * parisc hardware trap list
+ *
+ * Documented in section 3 "Addressing and Access Control" of the
+ * "PA-RISC 1.1 Architecture and Instruction Set Reference Manual"
+ * https://parisc.wiki.kernel.org/index.php/File:Pa11_acd.pdf
+ *
+ * For implementation see handle_interruption() in traps.c
+ */
+static const char * const trap_description[] = {
+ [1] "High-priority machine check (HPMC)",
+ [2] "Power failure interrupt",
+ [3] "Recovery counter trap",
+ [5] "Low-priority machine check",
+ [6] "Instruction TLB miss fault",
+ [7] "Instruction access rights / protection trap",
+ [8] "Illegal instruction trap",
+ [9] "Break instruction trap",
+ [10] "Privileged operation trap",
+ [11] "Privileged register trap",
+ [12] "Overflow trap",
+ [13] "Conditional trap",
+ [14] "FP Assist Exception trap",
+ [15] "Data TLB miss fault",
+ [16] "Non-access ITLB miss fault",
+ [17] "Non-access DTLB miss fault",
+ [18] "Data memory protection/unaligned access trap",
+ [19] "Data memory break trap",
+ [20] "TLB dirty bit trap",
+ [21] "Page reference trap",
+ [22] "Assist emulation trap",
+ [25] "Taken branch trap",
+ [26] "Data memory access rights trap",
+ [27] "Data memory protection ID trap",
+ [28] "Unaligned data reference trap",
+};
+
+const char *trap_name(unsigned long code)
+{
+ const char *t = NULL;
+
+ if (code < ARRAY_SIZE(trap_description))
+ t = trap_description[code];
+
+ return t ? t : "Unknown trap";
+}
+
+/*
+ * Print out info about fatal segfaults, if the show_unhandled_signals
+ * sysctl is set:
+ */
+static inline void
+show_signal_msg(struct pt_regs *regs, unsigned long code,
+ unsigned long address, struct task_struct *tsk,
+ struct vm_area_struct *vma)
+{
+ if (!unhandled_signal(tsk, SIGSEGV))
+ return;
+
+ if (!printk_ratelimit())
+ return;
+
+ pr_warn("\n");
+ pr_warn("do_page_fault() command='%s' type=%lu address=0x%08lx",
+ tsk->comm, code, address);
+ print_vma_addr(KERN_CONT " in ", regs->iaoq[0]);
+
+ pr_cont("\ntrap #%lu: %s%c", code, trap_name(code),
+ vma ? ',':'\n');
+
+ if (vma)
+ pr_cont(" vm_start = 0x%08lx, vm_end = 0x%08lx\n",
+ vma->vm_start, vma->vm_end);
+
+ show_regs(regs);
+}
+
+void do_page_fault(struct pt_regs *regs, unsigned long code,
+ unsigned long address)
+{
+ struct vm_area_struct *vma, *prev_vma;
+ struct task_struct *tsk;
+ struct mm_struct *mm;
+ unsigned long acc_type;
+ vm_fault_t fault = 0;
+ unsigned int flags;
+
+ if (faulthandler_disabled())
+ goto no_context;
+
+ tsk = current;
+ mm = tsk->mm;
+ if (!mm)
+ goto no_context;
+
+ flags = FAULT_FLAG_DEFAULT;
+ if (user_mode(regs))
+ flags |= FAULT_FLAG_USER;
+
+ acc_type = parisc_acctyp(code, regs->iir);
+ if (acc_type & VM_WRITE)
+ flags |= FAULT_FLAG_WRITE;
+ perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address);
+retry:
+ mmap_read_lock(mm);
+ vma = find_vma_prev(mm, address, &prev_vma);
+ if (!vma || address < vma->vm_start)
+ goto check_expansion;
+/*
+ * Ok, we have a good vm_area for this memory access. We still need to
+ * check the access permissions.
+ */
+
+good_area:
+
+ if ((vma->vm_flags & acc_type) != acc_type)
+ 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(vma, address, flags, regs);
+
+ if (fault_signal_pending(fault, regs))
+ return;
+
+ if (unlikely(fault & VM_FAULT_ERROR)) {
+ /*
+ * We hit a shared mapping outside of the file, or some
+ * other thing happened to us that made us unable to
+ * handle the page fault gracefully.
+ */
+ if (fault & VM_FAULT_OOM)
+ goto out_of_memory;
+ else if (fault & VM_FAULT_SIGSEGV)
+ goto bad_area;
+ else if (fault & (VM_FAULT_SIGBUS|VM_FAULT_HWPOISON|
+ VM_FAULT_HWPOISON_LARGE))
+ goto bad_area;
+ BUG();
+ }
+ if (flags & FAULT_FLAG_ALLOW_RETRY) {
+ if (fault & VM_FAULT_RETRY) {
+ /*
+ * No need to mmap_read_unlock(mm) as we would
+ * have already released it in __lock_page_or_retry
+ * in mm/filemap.c.
+ */
+ flags |= FAULT_FLAG_TRIED;
+ goto retry;
+ }
+ }
+ mmap_read_unlock(mm);
+ return;
+
+check_expansion:
+ vma = prev_vma;
+ if (vma && (expand_stack(vma, address) == 0))
+ goto good_area;
+
+/*
+ * Something tried to access memory that isn't in our memory map..
+ */
+bad_area:
+ mmap_read_unlock(mm);
+
+ if (user_mode(regs)) {
+ int signo, si_code;
+
+ switch (code) {
+ case 15: /* Data TLB miss fault/Data page fault */
+ /* send SIGSEGV when outside of vma */
+ if (!vma ||
+ address < vma->vm_start || address >= vma->vm_end) {
+ signo = SIGSEGV;
+ si_code = SEGV_MAPERR;
+ break;
+ }
+
+ /* send SIGSEGV for wrong permissions */
+ if ((vma->vm_flags & acc_type) != acc_type) {
+ signo = SIGSEGV;
+ si_code = SEGV_ACCERR;
+ break;
+ }
+
+ /* probably address is outside of mapped file */
+ fallthrough;
+ case 17: /* NA data TLB miss / page fault */
+ case 18: /* Unaligned access - PCXS only */
+ signo = SIGBUS;
+ si_code = (code == 18) ? BUS_ADRALN : BUS_ADRERR;
+ break;
+ case 16: /* Non-access instruction TLB miss fault */
+ case 26: /* PCXL: Data memory access rights trap */
+ default:
+ signo = SIGSEGV;
+ si_code = (code == 26) ? SEGV_ACCERR : SEGV_MAPERR;
+ break;
+ }
+#ifdef CONFIG_MEMORY_FAILURE
+ if (fault & (VM_FAULT_HWPOISON|VM_FAULT_HWPOISON_LARGE)) {
+ unsigned int lsb = 0;
+ printk(KERN_ERR
+ "MCE: Killing %s:%d due to hardware memory corruption fault at %08lx\n",
+ tsk->comm, tsk->pid, address);
+ /*
+ * Either small page or large page may be poisoned.
+ * In other words, VM_FAULT_HWPOISON_LARGE and
+ * VM_FAULT_HWPOISON are mutually exclusive.
+ */
+ if (fault & VM_FAULT_HWPOISON_LARGE)
+ lsb = hstate_index_to_shift(VM_FAULT_GET_HINDEX(fault));
+ else if (fault & VM_FAULT_HWPOISON)
+ lsb = PAGE_SHIFT;
+
+ force_sig_mceerr(BUS_MCEERR_AR, (void __user *) address,
+ lsb);
+ return;
+ }
+#endif
+ show_signal_msg(regs, code, address, tsk, vma);
+
+ force_sig_fault(signo, si_code, (void __user *) address);
+ return;
+ }
+
+no_context:
+
+ if (!user_mode(regs) && fixup_exception(regs)) {
+ return;
+ }
+
+ parisc_terminate("Bad Address (null pointer deref?)", regs, code, address);
+
+ out_of_memory:
+ mmap_read_unlock(mm);
+ if (!user_mode(regs))
+ goto no_context;
+ pagefault_out_of_memory();
+}
+
+/* Handle non-access data TLB miss faults.
+ *
+ * For probe instructions, accesses to userspace are considered allowed
+ * if they lie in a valid VMA and the access type matches. We are not
+ * allowed to handle MM faults here so there may be situations where an
+ * actual access would fail even though a probe was successful.
+ */
+int
+handle_nadtlb_fault(struct pt_regs *regs)
+{
+ unsigned long insn = regs->iir;
+ int breg, treg, xreg, val = 0;
+ struct vm_area_struct *vma, *prev_vma;
+ struct task_struct *tsk;
+ struct mm_struct *mm;
+ unsigned long address;
+ unsigned long acc_type;
+
+ switch (insn & 0x380) {
+ case 0x280:
+ /* FDC instruction */
+ fallthrough;
+ case 0x380:
+ /* PDC and FIC instructions */
+ if (printk_ratelimit()) {
+ pr_warn("BUG: nullifying cache flush/purge instruction\n");
+ show_regs(regs);
+ }
+ if (insn & 0x20) {
+ /* Base modification */
+ breg = (insn >> 21) & 0x1f;
+ xreg = (insn >> 16) & 0x1f;
+ if (breg && xreg)
+ regs->gr[breg] += regs->gr[xreg];
+ }
+ regs->gr[0] |= PSW_N;
+ return 1;
+
+ case 0x180:
+ /* PROBE instruction */
+ treg = insn & 0x1f;
+ if (regs->isr) {
+ tsk = current;
+ mm = tsk->mm;
+ if (mm) {
+ /* Search for VMA */
+ address = regs->ior;
+ mmap_read_lock(mm);
+ vma = find_vma_prev(mm, address, &prev_vma);
+ mmap_read_unlock(mm);
+
+ /*
+ * Check if access to the VMA is okay.
+ * We don't allow for stack expansion.
+ */
+ acc_type = (insn & 0x40) ? VM_WRITE : VM_READ;
+ if (vma
+ && address >= vma->vm_start
+ && (vma->vm_flags & acc_type) == acc_type)
+ val = 1;
+ }
+ }
+ if (treg)
+ regs->gr[treg] = val;
+ regs->gr[0] |= PSW_N;
+ return 1;
+
+ case 0x300:
+ /* LPA instruction */
+ if (insn & 0x20) {
+ /* Base modification */
+ breg = (insn >> 21) & 0x1f;
+ xreg = (insn >> 16) & 0x1f;
+ if (breg && xreg)
+ regs->gr[breg] += regs->gr[xreg];
+ }
+ treg = insn & 0x1f;
+ if (treg)
+ regs->gr[treg] = 0;
+ regs->gr[0] |= PSW_N;
+ return 1;
+
+ default:
+ break;
+ }
+
+ return 0;
+}
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