arch/arc/include/asm/uaccess.h

File Facts

System

Linux kernel

Corpus path

arch/arc/include/asm/uaccess.h

Extension

.h

Size

15883 bytes

Lines

638

Domain

Architecture Layer

Bucket

arch/arc

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.

Dependency Surface

• linux/string.h
• asm-generic/uaccess.h

Detected Declarations

• function raw_copy_from_user
• function raw_copy_to_user
• function __clear_user

Annotated Snippet

if (orig_n / 16) {
			orig_n = orig_n % 16;

			__asm__ __volatile__(
			"	lsr   lp_count, %7,4		\n"
			"	lp    3f			\n"
			"1:	ld.ab   %3, [%2, 4]		\n"
			"11:	ld.ab   %4, [%2, 4]		\n"
			"12:	ld.ab   %5, [%2, 4]		\n"
			"13:	ld.ab   %6, [%2, 4]		\n"
			"	st.ab   %3, [%1, 4]		\n"
			"	st.ab   %4, [%1, 4]		\n"
			"	st.ab   %5, [%1, 4]		\n"
			"	st.ab   %6, [%1, 4]		\n"
			"	sub     %0,%0,16		\n"
			"3:	;nop				\n"
			"	.section .fixup, \"ax\"		\n"
			"	.align 4			\n"
			"4:	j   3b				\n"
			"	.previous			\n"
			"	.section __ex_table, \"a\"	\n"
			"	.align 4			\n"
			"	.word   1b, 4b			\n"
			"	.word   11b,4b			\n"
			"	.word   12b,4b			\n"
			"	.word   13b,4b			\n"
			"	.previous			\n"
			: "+r" (res), "+r"(to), "+r"(from),
			  "=r"(tmp1), "=r"(tmp2), "=r"(tmp3), "=r"(tmp4)
			: "ir"(n)
			: "lp_count", "memory");
		}
		if (orig_n / 8) {
			orig_n = orig_n % 8;

			__asm__ __volatile__(
			"14:	ld.ab   %3, [%2,4]		\n"
			"15:	ld.ab   %4, [%2,4]		\n"
			"	st.ab   %3, [%1,4]		\n"
			"	st.ab   %4, [%1,4]		\n"
			"	sub     %0,%0,8			\n"
			"31:	;nop				\n"
			"	.section .fixup, \"ax\"		\n"
			"	.align 4			\n"
			"4:	j   31b				\n"
			"	.previous			\n"
			"	.section __ex_table, \"a\"	\n"
			"	.align 4			\n"
			"	.word   14b,4b			\n"
			"	.word   15b,4b			\n"
			"	.previous			\n"
			: "+r" (res), "+r"(to), "+r"(from),
			  "=r"(tmp1), "=r"(tmp2)
			:
			: "memory");
		}
		if (orig_n / 4) {
			orig_n = orig_n % 4;

			__asm__ __volatile__(
			"16:	ld.ab   %3, [%2,4]		\n"
			"	st.ab   %3, [%1,4]		\n"
			"	sub     %0,%0,4			\n"
			"32:	;nop				\n"
			"	.section .fixup, \"ax\"		\n"
			"	.align 4			\n"
			"4:	j   32b				\n"
			"	.previous			\n"
			"	.section __ex_table, \"a\"	\n"
			"	.align 4			\n"
			"	.word   16b,4b			\n"
			"	.previous			\n"
			: "+r" (res), "+r"(to), "+r"(from), "=r"(tmp1)
			:
			: "memory");
		}
		if (orig_n / 2) {
			orig_n = orig_n % 2;

			__asm__ __volatile__(
			"17:	ldw.ab   %3, [%2,2]		\n"
			"	stw.ab   %3, [%1,2]		\n"
			"	sub      %0,%0,2		\n"
			"33:	;nop				\n"
			"	.section .fixup, \"ax\"		\n"
			"	.align 4			\n"
			"4:	j   33b				\n"
			"	.previous			\n"
			"	.section __ex_table, \"a\"	\n"
			"	.align 4			\n"

Annotation

• Immediate include surface: `linux/string.h`, `asm-generic/uaccess.h`.
• Detected declarations: `function raw_copy_from_user`, `function raw_copy_to_user`, `function __clear_user`.
• Atlas domain: Architecture Layer / arch/arc.
• 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.