arch/powerpc/platforms/pseries/papr-sysparm.c

File Facts

System

Linux kernel

Corpus path

arch/powerpc/platforms/pseries/papr-sysparm.c

Extension

.c

Size

8691 bytes

Lines

353

Domain

Architecture Layer

Bucket

arch/powerpc

Inferred role

Architecture Layer: operation-table or driver-model contract

Status

pattern 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 an operation table; this is where Linux turns generic core objects into subsystem-specific behavior.
• 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/anon_inodes.h
• linux/bug.h
• linux/file.h
• linux/fs.h
• linux/init.h
• linux/kernel.h
• linux/miscdevice.h
• linux/printk.h
• linux/slab.h
• linux/uaccess.h
• asm/machdep.h
• asm/papr-sysparm.h
• asm/rtas-work-area.h
• asm/rtas.h

Detected Declarations

• function papr_sysparm_buf_free
• function papr_sysparm_buf_get_length
• function papr_sysparm_buf_set_length
• function papr_sysparm_buf_clamp_length
• function papr_sysparm_buf_can_submit
• function papr_sysparm_get
• function papr_sysparm_set
• function papr_sysparm_buf_from_user
• function papr_sysparm_buf_to_user
• function papr_sysparm_ioctl_get
• function papr_sysparm_ioctl_set
• function papr_sysparm_ioctl
• function papr_sysparm_init

Annotated Snippet

static const struct file_operations papr_sysparm_ops = {
	.unlocked_ioctl = papr_sysparm_ioctl,
};

static struct miscdevice papr_sysparm_dev = {
	.minor = MISC_DYNAMIC_MINOR,
	.name = "papr-sysparm",
	.fops = &papr_sysparm_ops,
};

static __init int papr_sysparm_init(void)
{
	if (!rtas_function_implemented(RTAS_FN_IBM_GET_SYSTEM_PARAMETER))
		return -ENODEV;

	return misc_register(&papr_sysparm_dev);
}
machine_device_initcall(pseries, papr_sysparm_init);

Annotation

• Immediate include surface: `linux/anon_inodes.h`, `linux/bug.h`, `linux/file.h`, `linux/fs.h`, `linux/init.h`, `linux/kernel.h`, `linux/miscdevice.h`, `linux/printk.h`.
• Detected declarations: `function papr_sysparm_buf_free`, `function papr_sysparm_buf_get_length`, `function papr_sysparm_buf_set_length`, `function papr_sysparm_buf_clamp_length`, `function papr_sysparm_buf_can_submit`, `function papr_sysparm_get`, `function papr_sysparm_set`, `function papr_sysparm_buf_from_user`, `function papr_sysparm_buf_to_user`, `function papr_sysparm_ioctl_get`.
• Atlas domain: Architecture Layer / arch/powerpc.
• Implementation status: pattern 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.