arch/s390/kernel/runtime_instr.c

File Facts

System

Linux kernel

Corpus path

arch/s390/kernel/runtime_instr.c

Extension

.c

Size

2252 bytes

Lines

103

Domain

Architecture Layer

Bucket

arch/s390

Inferred role

Architecture Layer: syscall or user/kernel boundary

Status

core 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.
• Defines or participates in a user/kernel boundary; inspect argument validation, copy_from_user/copy_to_user, credentials, and dispatch target.
• Allocates kernel memory; connect allocation flags and lifetime to context constraints.
• Defines or uses C structs; map object ownership, embedded links, reference counts, and lock ownership.

Dependency Surface

• linux/kernel.h
• linux/syscalls.h
• linux/signal.h
• linux/mm.h
• linux/slab.h
• linux/init.h
• linux/errno.h
• linux/kernel_stat.h
• linux/sched/task_stack.h
• asm/runtime_instr.h
• asm/cpu_mf.h
• asm/irq.h
• entry.h

Detected Declarations

• syscall s390_runtime_instr
• function runtime_instr_release
• function disable_runtime_instr
• function init_runtime_instr_cb

Annotated Snippet

SYSCALL_DEFINE2(s390_runtime_instr, int, command, int, signum)
{
	struct runtime_instr_cb *cb;

	if (!test_facility(64))
		return -EOPNOTSUPP;

	if (command == S390_RUNTIME_INSTR_STOP) {
		disable_runtime_instr();
		return 0;
	}

	if (command != S390_RUNTIME_INSTR_START)
		return -EINVAL;

	if (!current->thread.ri_cb) {
		cb = kzalloc_obj(*cb);
		if (!cb)
			return -ENOMEM;
	} else {
		cb = current->thread.ri_cb;
		memset(cb, 0, sizeof(*cb));
	}

	init_runtime_instr_cb(cb);

	/* now load the control block to make it available */
	preempt_disable();
	current->thread.ri_cb = cb;
	load_runtime_instr_cb(cb);
	preempt_enable();
	return 0;
}

Annotation

• Immediate include surface: `linux/kernel.h`, `linux/syscalls.h`, `linux/signal.h`, `linux/mm.h`, `linux/slab.h`, `linux/init.h`, `linux/errno.h`, `linux/kernel_stat.h`.
• Detected declarations: `syscall s390_runtime_instr`, `function runtime_instr_release`, `function disable_runtime_instr`, `function init_runtime_instr_cb`.
• Atlas domain: Architecture Layer / arch/s390.
• Implementation status: core implementation candidate.

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.