arch/microblaze/mm/fault.c

File Facts

System

Linux kernel

Corpus path

arch/microblaze/mm/fault.c

Extension

.c

Size

7994 bytes

Lines

300

Domain

Architecture Layer

Bucket

arch/microblaze

Inferred role

Architecture Layer: implementation source

Status

source implementation candidate

Why This File Exists

CPU and platform-specific kernel glue: boot entry, traps, syscall entry, interrupts, page tables, context switch, and low-level barriers.

• CPU and platform-specific kernel glue: boot entry, traps, syscall entry, interrupts, page tables, context switch, and low-level barriers.
• Touches user memory; correctness depends on fault-safe copying and privilege boundary handling.
• Defines or uses C structs; map object ownership, embedded links, reference counts, and lock ownership.

Dependency Surface

• linux/extable.h
• linux/signal.h
• linux/sched.h
• linux/kernel.h
• linux/errno.h
• linux/string.h
• linux/types.h
• linux/ptrace.h
• linux/mman.h
• linux/mm.h
• linux/interrupt.h
• linux/perf_event.h
• asm/page.h
• asm/mmu.h
• linux/mmu_context.h
• linux/uaccess.h
• asm/exceptions.h

Detected Declarations

• function store_updates_sp
• function bad_page_fault
• function do_page_fault
• function pointer

Annotated Snippet

fault = handle_mm_fault(vma, address, flags, regs);

	if (fault_signal_pending(fault, regs)) {
		if (!user_mode(regs))
			bad_page_fault(regs, address, SIGBUS);
		return;
	}

	/* The fault is fully completed (including releasing mmap lock) */
	if (fault & VM_FAULT_COMPLETED)
		return;

	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);

	/*
	 * keep track of tlb+htab misses that are good addrs but
	 * just need pte's created via handle_mm_fault()
	 * -- Cort
	 */
	pte_misses++;
	return;

bad_area:
	mmap_read_unlock(mm);

bad_area_nosemaphore:
	pte_errors++;

	/* User mode accesses cause a SIGSEGV */
	if (user_mode(regs)) {
		_exception(SIGSEGV, regs, code, address);
		return;
	}

	bad_page_fault(regs, address, SIGSEGV);
	return;

/*
 * 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:
	mmap_read_unlock(mm);
	if (!user_mode(regs))
		bad_page_fault(regs, address, SIGKILL);
	else
		pagefault_out_of_memory();
	return;

do_sigbus:
	mmap_read_unlock(mm);
	if (user_mode(regs)) {
		force_sig_fault(SIGBUS, BUS_ADRERR, (void __user *)address);
		return;
	}
	bad_page_fault(regs, address, SIGBUS);
}

Annotation

• Immediate include surface: `linux/extable.h`, `linux/signal.h`, `linux/sched.h`, `linux/kernel.h`, `linux/errno.h`, `linux/string.h`, `linux/types.h`, `linux/ptrace.h`.
• Detected declarations: `function store_updates_sp`, `function bad_page_fault`, `function do_page_fault`, `function pointer`.
• Atlas domain: Architecture Layer / arch/microblaze.
• Implementation status: source implementation candidate.
• This snippet crosses the user/kernel memory boundary; validate fault handling and access checks before translating the pattern.

Implementation Notes

• This generated page is the file-by-file coverage layer; curated subsystem chapters should link here when they synthesize a multi-file control flow.
• Core OS pages should be promoted from atlas-only to deep-reviewed when they explain data structures, invariants, locking, lifecycle, and C implementation snippets.
• Driver-family pages are intentionally pattern-oriented unless they are part of the selected PCIe/NVMe representative device path.