diff options
Diffstat (limited to 'arch/hexagon/mm/vm_fault.c')
| -rw-r--r-- | arch/hexagon/mm/vm_fault.c | 176 |
1 files changed, 176 insertions, 0 deletions
diff --git a/arch/hexagon/mm/vm_fault.c b/arch/hexagon/mm/vm_fault.c new file mode 100644 index 0000000000..7295ea3f8c --- /dev/null +++ b/arch/hexagon/mm/vm_fault.c @@ -0,0 +1,176 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Memory fault handling for Hexagon + * + * Copyright (c) 2010-2011, The Linux Foundation. All rights reserved. + */ + +/* + * Page fault handling for the Hexagon Virtual Machine. + * Can also be called by a native port emulating the HVM + * execptions. + */ + +#include <asm/traps.h> +#include <linux/uaccess.h> +#include <linux/mm.h> +#include <linux/sched/signal.h> +#include <linux/signal.h> +#include <linux/extable.h> +#include <linux/hardirq.h> +#include <linux/perf_event.h> + +/* + * Decode of hardware exception sends us to one of several + * entry points. At each, we generate canonical arguments + * for handling by the abstract memory management code. + */ +#define FLT_IFETCH -1 +#define FLT_LOAD 0 +#define FLT_STORE 1 + + +/* + * Canonical page fault handler + */ +void do_page_fault(unsigned long address, long cause, struct pt_regs *regs) +{ + struct vm_area_struct *vma; + struct mm_struct *mm = current->mm; + int si_signo; + int si_code = SEGV_MAPERR; + vm_fault_t fault; + const struct exception_table_entry *fixup; + unsigned int flags = FAULT_FLAG_DEFAULT; + + /* + * If we're in an interrupt or have no user context, + * then must not take the fault. + */ + if (unlikely(in_interrupt() || !mm)) + goto no_context; + + local_irq_enable(); + + if (user_mode(regs)) + flags |= FAULT_FLAG_USER; + + perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address); +retry: + vma = lock_mm_and_find_vma(mm, address, regs); + if (unlikely(!vma)) + goto bad_area_nosemaphore; + + /* Address space is OK. Now check access rights. */ + si_code = SEGV_ACCERR; + + switch (cause) { + case FLT_IFETCH: + if (!(vma->vm_flags & VM_EXEC)) + goto bad_area; + break; + case FLT_LOAD: + if (!(vma->vm_flags & VM_READ)) + goto bad_area; + break; + case FLT_STORE: + if (!(vma->vm_flags & VM_WRITE)) + goto bad_area; + flags |= FAULT_FLAG_WRITE; + break; + } + + fault = handle_mm_fault(vma, address, flags, regs); + + if (fault_signal_pending(fault, regs)) { + if (!user_mode(regs)) + goto no_context; + return; + } + + /* The fault is fully completed (including releasing mmap lock) */ + if (fault & VM_FAULT_COMPLETED) + return; + + /* The most common case -- we are done. */ + if (likely(!(fault & VM_FAULT_ERROR))) { + if (fault & VM_FAULT_RETRY) { + flags |= FAULT_FLAG_TRIED; + goto retry; + } + + mmap_read_unlock(mm); + return; + } + + mmap_read_unlock(mm); + + /* Handle copyin/out exception cases */ + if (!user_mode(regs)) + goto no_context; + + if (fault & VM_FAULT_OOM) { + pagefault_out_of_memory(); + return; + } + + /* User-mode address is in the memory map, but we are + * unable to fix up the page fault. + */ + if (fault & VM_FAULT_SIGBUS) { + si_signo = SIGBUS; + si_code = BUS_ADRERR; + } + /* Address is not in the memory map */ + else { + si_signo = SIGSEGV; + si_code = SEGV_ACCERR; + } + force_sig_fault(si_signo, si_code, (void __user *)address); + return; + +bad_area: + mmap_read_unlock(mm); + +bad_area_nosemaphore: + if (user_mode(regs)) { + force_sig_fault(SIGSEGV, si_code, (void __user *)address); + return; + } + /* Kernel-mode fault falls through */ + +no_context: + fixup = search_exception_tables(pt_elr(regs)); + if (fixup) { + pt_set_elr(regs, fixup->fixup); + return; + } + + /* Things are looking very, very bad now */ + bust_spinlocks(1); + printk(KERN_EMERG "Unable to handle kernel paging request at " + "virtual address 0x%08lx, regs %p\n", address, regs); + die("Bad Kernel VA", regs, SIGKILL); +} + + +void read_protection_fault(struct pt_regs *regs) +{ + unsigned long badvadr = pt_badva(regs); + + do_page_fault(badvadr, FLT_LOAD, regs); +} + +void write_protection_fault(struct pt_regs *regs) +{ + unsigned long badvadr = pt_badva(regs); + + do_page_fault(badvadr, FLT_STORE, regs); +} + +void execute_protection_fault(struct pt_regs *regs) +{ + unsigned long badvadr = pt_badva(regs); + + do_page_fault(badvadr, FLT_IFETCH, regs); +} |