arch/s390/kernel/guarded_storage.c

File Facts

System

Linux kernel

Corpus path

arch/s390/kernel/guarded_storage.c

Extension

.c

Size

2576 bytes

Lines

130

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.
• Touches user memory; correctness depends on fault-safe copying and privilege boundary handling.
• 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/cpufeature.h
• linux/kernel.h
• linux/syscalls.h
• linux/signal.h
• linux/mm.h
• linux/slab.h
• asm/guarded_storage.h
• entry.h

Detected Declarations

• syscall s390_guarded_storage
• function Author
• function gs_enable
• function gs_disable
• function gs_set_bc_cb
• function gs_clear_bc_cb
• function gs_load_bc_cb
• function gs_broadcast

Annotated Snippet

SYSCALL_DEFINE2(s390_guarded_storage, int, command,
		struct gs_cb __user *, gs_cb)
{
	if (!cpu_has_gs())
		return -EOPNOTSUPP;
	switch (command) {
	case GS_ENABLE:
		return gs_enable();
	case GS_DISABLE:
		return gs_disable();
	case GS_SET_BC_CB:
		return gs_set_bc_cb(gs_cb);
	case GS_CLEAR_BC_CB:
		return gs_clear_bc_cb();
	case GS_BROADCAST:
		return gs_broadcast();
	default:
		return -EINVAL;
	}
}

Annotation

• Immediate include surface: `linux/cpufeature.h`, `linux/kernel.h`, `linux/syscalls.h`, `linux/signal.h`, `linux/mm.h`, `linux/slab.h`, `asm/guarded_storage.h`, `entry.h`.
• Detected declarations: `syscall s390_guarded_storage`, `function Author`, `function gs_enable`, `function gs_disable`, `function gs_set_bc_cb`, `function gs_clear_bc_cb`, `function gs_load_bc_cb`, `function gs_broadcast`.
• Atlas domain: Architecture Layer / arch/s390.
• Implementation status: core 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.