summaryrefslogtreecommitdiff
path: root/arch/arc/mm/fault.c
diff options
context:
space:
mode:
authorLinus Torvalds <torvalds@linux-foundation.org>2013-03-02 19:58:56 +0400
committerLinus Torvalds <torvalds@linux-foundation.org>2013-03-02 19:58:56 +0400
commite23b62256a361611cbd45cd1456638f1a5106b5c (patch)
tree472968c961432a1d9d0c3634ca20433f1d9cd29b /arch/arc/mm/fault.c
parentaebb2afd5420c860b7fbc3882a323ef1247fbf16 (diff)
parent8ccfe6675fa974bd06d64f74d0fdee6a5267d2aa (diff)
downloadlinux-e23b62256a361611cbd45cd1456638f1a5106b5c.tar.xz
Merge tag 'arc-v3.9-rc1-late' of git://git.kernel.org/pub/scm/linux/kernel/git/vgupta/arc
Pull new ARC architecture from Vineet Gupta: "Initial ARC Linux port with some fixes on top for 3.9-rc1: I would like to introduce the Linux port to ARC Processors (from Synopsys) for 3.9-rc1. The patch-set has been discussed on the public lists since Nov and has received a fair bit of review, specially from Arnd, tglx, Al and other subsystem maintainers for DeviceTree, kgdb... The arch bits are in arch/arc, some asm-generic changes (acked by Arnd), a minor change to PARISC (acked by Helge). The series is a touch bigger for a new port for 2 main reasons: 1. It enables a basic kernel in first sub-series and adds ptrace/kgdb/.. later 2. Some of the fallout of review (DeviceTree support, multi-platform- image support) were added on top of orig series, primarily to record the revision history. This updated pull request additionally contains - fixes due to our GNU tools catching up with the new syscall/ptrace ABI - some (minor) cross-arch Kconfig updates." * tag 'arc-v3.9-rc1-late' of git://git.kernel.org/pub/scm/linux/kernel/git/vgupta/arc: (82 commits) ARC: split elf.h into uapi and export it for userspace ARC: Fixup the current ABI version ARC: gdbserver using regset interface possibly broken ARC: Kconfig cleanup tracking cross-arch Kconfig pruning in merge window ARC: make a copy of flat DT ARC: [plat-arcfpga] DT arc-uart bindings change: "baud" => "current-speed" ARC: Ensure CONFIG_VIRT_TO_BUS is not enabled ARC: Fix pt_orig_r8 access ARC: [3.9] Fallout of hlist iterator update ARC: 64bit RTSC timestamp hardware issue ARC: Don't fiddle with non-existent caches ARC: Add self to MAINTAINERS ARC: Provide a default serial.h for uart drivers needing BASE_BAUD ARC: [plat-arcfpga] defconfig for fully loaded ARC Linux ARC: [Review] Multi-platform image #8: platform registers SMP callbacks ARC: [Review] Multi-platform image #7: SMP common code to use callbacks ARC: [Review] Multi-platform image #6: cpu-to-dma-addr optional ARC: [Review] Multi-platform image #5: NR_IRQS defined by ARC core ARC: [Review] Multi-platform image #4: Isolate platform headers ARC: [Review] Multi-platform image #3: switch to board callback ...
Diffstat (limited to 'arch/arc/mm/fault.c')
-rw-r--r--arch/arc/mm/fault.c228
1 files changed, 228 insertions, 0 deletions
diff --git a/arch/arc/mm/fault.c b/arch/arc/mm/fault.c
new file mode 100644
index 000000000000..af55aab803d2
--- /dev/null
+++ b/arch/arc/mm/fault.c
@@ -0,0 +1,228 @@
+/* Page Fault Handling for ARC (TLB Miss / ProtV)
+ *
+ * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/signal.h>
+#include <linux/interrupt.h>
+#include <linux/sched.h>
+#include <linux/errno.h>
+#include <linux/ptrace.h>
+#include <linux/version.h>
+#include <linux/uaccess.h>
+#include <linux/kdebug.h>
+#include <asm/pgalloc.h>
+
+static int handle_vmalloc_fault(struct mm_struct *mm, unsigned long address)
+{
+ /*
+ * Synchronize this task's top level page-table
+ * with the 'reference' page table.
+ */
+ pgd_t *pgd, *pgd_k;
+ pud_t *pud, *pud_k;
+ pmd_t *pmd, *pmd_k;
+
+ pgd = pgd_offset_fast(mm, address);
+ pgd_k = pgd_offset_k(address);
+
+ if (!pgd_present(*pgd_k))
+ goto bad_area;
+
+ pud = pud_offset(pgd, address);
+ pud_k = pud_offset(pgd_k, address);
+ if (!pud_present(*pud_k))
+ goto bad_area;
+
+ pmd = pmd_offset(pud, address);
+ pmd_k = pmd_offset(pud_k, address);
+ if (!pmd_present(*pmd_k))
+ goto bad_area;
+
+ set_pmd(pmd, *pmd_k);
+
+ /* XXX: create the TLB entry here */
+ return 0;
+
+bad_area:
+ return 1;
+}
+
+void do_page_fault(struct pt_regs *regs, int write, unsigned long address,
+ unsigned long cause_code)
+{
+ struct vm_area_struct *vma = NULL;
+ struct task_struct *tsk = current;
+ struct mm_struct *mm = tsk->mm;
+ siginfo_t info;
+ int fault, ret;
+ unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE |
+ (write ? FAULT_FLAG_WRITE : 0);
+
+ /*
+ * 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 (address >= VMALLOC_START && address <= VMALLOC_END) {
+ ret = handle_vmalloc_fault(mm, address);
+ if (unlikely(ret))
+ goto bad_area_nosemaphore;
+ else
+ return;
+ }
+
+ 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;
+
+retry:
+ 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;
+
+ /*
+ * Ok, we have a good vm_area for this memory access, so
+ * we can handle it..
+ */
+good_area:
+ info.si_code = SEGV_ACCERR;
+
+ /* Handle protection violation, execute on heap or stack */
+
+ if (cause_code == ((ECR_V_PROTV << 16) | ECR_C_PROTV_INST_FETCH))
+ goto bad_area;
+
+ if (write) {
+ if (!(vma->vm_flags & VM_WRITE))
+ goto bad_area;
+ } else {
+ if (!(vma->vm_flags & (VM_READ | VM_EXEC)))
+ goto bad_area;
+ }
+
+survive:
+ /*
+ * 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, flags);
+
+ /* If Pagefault was interrupted by SIGKILL, exit page fault "early" */
+ if (unlikely(fatal_signal_pending(current))) {
+ if ((fault & VM_FAULT_ERROR) && !(fault & VM_FAULT_RETRY))
+ up_read(&mm->mmap_sem);
+ if (user_mode(regs))
+ return;
+ }
+
+ if (likely(!(fault & VM_FAULT_ERROR))) {
+ if (flags & FAULT_FLAG_ALLOW_RETRY) {
+ /* To avoid updating stats twice for retry case */
+ if (fault & VM_FAULT_MAJOR)
+ tsk->maj_flt++;
+ else
+ tsk->min_flt++;
+
+ if (fault & VM_FAULT_RETRY) {
+ flags &= ~FAULT_FLAG_ALLOW_RETRY;
+ flags |= FAULT_FLAG_TRIED;
+ goto retry;
+ }
+ }
+
+ /* Fault Handled Gracefully */
+ up_read(&mm->mmap_sem);
+ return;
+ }
+
+ /* TBD: switch to pagefault_out_of_memory() */
+ if (fault & VM_FAULT_OOM)
+ goto out_of_memory;
+ else if (fault & VM_FAULT_SIGBUS)
+ goto do_sigbus;
+
+ /* no man's land */
+ BUG();
+
+ /*
+ * 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 (user_mode(regs)) {
+ tsk->thread.fault_address = address;
+ tsk->thread.cause_code = cause_code;
+ info.si_signo = SIGSEGV;
+ info.si_errno = 0;
+ /* info.si_code has been set above */
+ info.si_addr = (void __user *)address;
+ force_sig_info(SIGSEGV, &info, tsk);
+ return;
+ }
+
+no_context:
+ /* Are we prepared to handle this kernel fault?
+ *
+ * (The kernel has valid exception-points in the source
+ * when it acesses user-memory. When it fails in one
+ * of those points, we find it in a table and do a jump
+ * to some fixup code that loads an appropriate error
+ * code)
+ */
+ if (fixup_exception(regs))
+ return;
+
+ die("Oops", regs, address, cause_code);
+
+out_of_memory:
+ if (is_global_init(tsk)) {
+ yield();
+ goto survive;
+ }
+ up_read(&mm->mmap_sem);
+
+ if (user_mode(regs))
+ do_group_exit(SIGKILL); /* This will never return */
+
+ goto no_context;
+
+do_sigbus:
+ up_read(&mm->mmap_sem);
+
+ if (!user_mode(regs))
+ goto no_context;
+
+ tsk->thread.fault_address = address;
+ tsk->thread.cause_code = cause_code;
+ info.si_signo = SIGBUS;
+ info.si_errno = 0;
+ info.si_code = BUS_ADRERR;
+ info.si_addr = (void __user *)address;
+ force_sig_info(SIGBUS, &info, tsk);
+}