arch/s390/kernel/sthyi.c

File Facts

System

Linux kernel

Corpus path

arch/s390/kernel/sthyi.c

Extension

.c

Size

13055 bytes

Lines

557

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.
• Uses kernel synchronization; read lock ordering, sleepability, and interrupt context assumptions before translating.
• 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/export.h
• linux/errno.h
• linux/pagemap.h
• linux/vmalloc.h
• linux/syscalls.h
• linux/mutex.h
• asm/asm-offsets.h
• asm/sclp.h
• asm/diag.h
• asm/sysinfo.h
• asm/ebcdic.h
• asm/facility.h
• asm/sthyi.h
• asm/asm.h
• entry.h

Detected Declarations

• syscall s390_sthyi
• struct hdr_sctn
• struct mac_sctn
• struct par_sctn
• struct sthyi_sctns
• struct cpu_inf
• struct lpar_cpu_inf
• struct sthyi_info
• enum hdr_flags
• enum mac_validity
• enum par_flag
• enum par_validity
• function cpu_id
• function scale_cap
• function fill_hdr
• function fill_stsi_mac
• function fill_stsi_par
• function fill_stsi
• function fill_diag_mac
• function is_diag204_cached
• function fill_diag
• function sthyi
• function fill_dst
• function sthyi_init_cache
• function sthyi_update_cache
• function sthyi_fill
• export sthyi_fill

Annotated Snippet

SYSCALL_DEFINE4(s390_sthyi, unsigned long, function_code, void __user *, buffer,
		u64 __user *, return_code, unsigned long, flags)
{
	u64 sthyi_rc;
	void *info;
	int r;

	if (flags)
		return -EINVAL;
	if (function_code != STHYI_FC_CP_IFL_CAP)
		return -EOPNOTSUPP;
	info = (void *)get_zeroed_page(GFP_KERNEL);
	if (!info)
		return -ENOMEM;
	r = sthyi_fill(info, &sthyi_rc);
	if (r < 0)
		goto out;
	if (return_code && put_user(sthyi_rc, return_code)) {
		r = -EFAULT;
		goto out;
	}
	if (copy_to_user(buffer, info, PAGE_SIZE))
		r = -EFAULT;
out:
	free_page((unsigned long)info);
	return r;
}

Annotation

• Immediate include surface: `linux/export.h`, `linux/errno.h`, `linux/pagemap.h`, `linux/vmalloc.h`, `linux/syscalls.h`, `linux/mutex.h`, `asm/asm-offsets.h`, `asm/sclp.h`.
• Detected declarations: `syscall s390_sthyi`, `struct hdr_sctn`, `struct mac_sctn`, `struct par_sctn`, `struct sthyi_sctns`, `struct cpu_inf`, `struct lpar_cpu_inf`, `struct sthyi_info`, `enum hdr_flags`, `enum mac_validity`.
• 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.
• Synchronization appears in or near this file; preserve lock ordering, sleepability, and interrupt-context constraints.

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.