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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 18:49:45 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 18:49:45 +0000 |
commit | 2c3c1048746a4622d8c89a29670120dc8fab93c4 (patch) | |
tree | 848558de17fb3008cdf4d861b01ac7781903ce39 /arch/ia64/mm/fault.c | |
parent | Initial commit. (diff) | |
download | linux-upstream.tar.xz linux-upstream.zip |
Adding upstream version 6.1.76.upstream/6.1.76upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'arch/ia64/mm/fault.c')
-rw-r--r-- | arch/ia64/mm/fault.c | 248 |
1 files changed, 248 insertions, 0 deletions
diff --git a/arch/ia64/mm/fault.c b/arch/ia64/mm/fault.c new file mode 100644 index 000000000..99a09abe1 --- /dev/null +++ b/arch/ia64/mm/fault.c @@ -0,0 +1,248 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * MMU fault handling support. + * + * Copyright (C) 1998-2002 Hewlett-Packard Co + * David Mosberger-Tang <davidm@hpl.hp.com> + */ +#include <linux/sched/signal.h> +#include <linux/kernel.h> +#include <linux/mm.h> +#include <linux/extable.h> +#include <linux/interrupt.h> +#include <linux/kprobes.h> +#include <linux/kdebug.h> +#include <linux/prefetch.h> +#include <linux/uaccess.h> +#include <linux/perf_event.h> + +#include <asm/processor.h> +#include <asm/exception.h> + +extern int die(char *, struct pt_regs *, long); + +/* + * Return TRUE if ADDRESS points at a page in the kernel's mapped segment + * (inside region 5, on ia64) and that page is present. + */ +static int +mapped_kernel_page_is_present (unsigned long address) +{ + pgd_t *pgd; + p4d_t *p4d; + pud_t *pud; + pmd_t *pmd; + pte_t *ptep, pte; + + pgd = pgd_offset_k(address); + if (pgd_none(*pgd) || pgd_bad(*pgd)) + return 0; + + p4d = p4d_offset(pgd, address); + if (p4d_none(*p4d) || p4d_bad(*p4d)) + return 0; + + pud = pud_offset(p4d, address); + if (pud_none(*pud) || pud_bad(*pud)) + return 0; + + pmd = pmd_offset(pud, address); + if (pmd_none(*pmd) || pmd_bad(*pmd)) + return 0; + + ptep = pte_offset_kernel(pmd, address); + if (!ptep) + return 0; + + pte = *ptep; + return pte_present(pte); +} + +# define VM_READ_BIT 0 +# define VM_WRITE_BIT 1 +# define VM_EXEC_BIT 2 + +void __kprobes +ia64_do_page_fault (unsigned long address, unsigned long isr, struct pt_regs *regs) +{ + int signal = SIGSEGV, code = SEGV_MAPERR; + struct vm_area_struct *vma, *prev_vma; + struct mm_struct *mm = current->mm; + unsigned long mask; + vm_fault_t fault; + unsigned int flags = FAULT_FLAG_DEFAULT; + + mask = ((((isr >> IA64_ISR_X_BIT) & 1UL) << VM_EXEC_BIT) + | (((isr >> IA64_ISR_W_BIT) & 1UL) << VM_WRITE_BIT)); + + /* mmap_lock is performance critical.... */ + prefetchw(&mm->mmap_lock); + + /* + * If we're in an interrupt or have no user context, we must not take the fault.. + */ + if (faulthandler_disabled() || !mm) + goto no_context; + + /* + * This is to handle the kprobes on user space access instructions + */ + if (kprobe_page_fault(regs, TRAP_BRKPT)) + return; + + if (user_mode(regs)) + flags |= FAULT_FLAG_USER; + if (mask & 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 && !prev_vma ) + goto bad_area; + + /* + * find_vma_prev() returns vma such that address < vma->vm_end or NULL + * + * May find no vma, but could be that the last vm area is the + * register backing store that needs to expand upwards, in + * this case vma will be null, but prev_vma will ne non-null + */ + if (( !vma && prev_vma ) || (address < vma->vm_start) ) { + vma = expand_stack(mm, address); + if (!vma) + goto bad_area_nosemaphore; + } + + code = SEGV_ACCERR; + + /* OK, we've got a good vm_area for this memory area. Check the access permissions: */ + +# if (((1 << VM_READ_BIT) != VM_READ || (1 << VM_WRITE_BIT) != VM_WRITE) \ + || (1 << VM_EXEC_BIT) != VM_EXEC) +# error File is out of sync with <linux/mm.h>. Please update. +# endif + + if (((isr >> IA64_ISR_R_BIT) & 1UL) && (!(vma->vm_flags & (VM_READ | VM_WRITE)))) + goto bad_area; + + if ((vma->vm_flags & mask) != mask) + 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; + + /* The fault is fully completed (including releasing mmap lock) */ + if (fault & VM_FAULT_COMPLETED) + return; + + if (unlikely(fault & VM_FAULT_ERROR)) { + /* + * We ran out of memory, 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) { + signal = SIGBUS; + goto bad_area; + } + 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); + return; + + bad_area: + mmap_read_unlock(mm); + bad_area_nosemaphore: + if ((isr & IA64_ISR_SP) + || ((isr & IA64_ISR_NA) && (isr & IA64_ISR_CODE_MASK) == IA64_ISR_CODE_LFETCH)) + { + /* + * This fault was due to a speculative load or lfetch.fault, set the "ed" + * bit in the psr to ensure forward progress. (Target register will get a + * NaT for ld.s, lfetch will be canceled.) + */ + ia64_psr(regs)->ed = 1; + return; + } + if (user_mode(regs)) { + force_sig_fault(signal, code, (void __user *) address, + 0, __ISR_VALID, isr); + return; + } + + no_context: + if ((isr & IA64_ISR_SP) + || ((isr & IA64_ISR_NA) && (isr & IA64_ISR_CODE_MASK) == IA64_ISR_CODE_LFETCH)) + { + /* + * This fault was due to a speculative load or lfetch.fault, set the "ed" + * bit in the psr to ensure forward progress. (Target register will get a + * NaT for ld.s, lfetch will be canceled.) + */ + ia64_psr(regs)->ed = 1; + return; + } + + /* + * Since we have no vma's for region 5, we might get here even if the address is + * valid, due to the VHPT walker inserting a non present translation that becomes + * stale. If that happens, the non present fault handler already purged the stale + * translation, which fixed the problem. So, we check to see if the translation is + * valid, and return if it is. + */ + if (REGION_NUMBER(address) == 5 && mapped_kernel_page_is_present(address)) + return; + + if (ia64_done_with_exception(regs)) + return; + + /* + * Oops. The kernel tried to access some bad page. We'll have to terminate things + * with extreme prejudice. + */ + bust_spinlocks(1); + + if (address < PAGE_SIZE) + printk(KERN_ALERT "Unable to handle kernel NULL pointer dereference (address %016lx)\n", address); + else + printk(KERN_ALERT "Unable to handle kernel paging request at " + "virtual address %016lx\n", address); + if (die("Oops", regs, isr)) + regs = NULL; + bust_spinlocks(0); + if (regs) + make_task_dead(SIGKILL); + return; + + out_of_memory: + mmap_read_unlock(mm); + if (!user_mode(regs)) + goto no_context; + pagefault_out_of_memory(); +} |