arch/powerpc/perf/callchain.h

File Facts

System

Linux kernel

Corpus path

arch/powerpc/perf/callchain.h

Extension

.h

Size

1081 bytes

Lines

36

Domain

Architecture Layer

Bucket

arch/powerpc

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.
• Defines or uses C structs; map object ownership, embedded links, reference counts, and lock ownership.

Dependency Surface

• No C-style include directives detected by the generator.

Detected Declarations

• function invalid_user_sp
• function do_page_fault

Annotated Snippet

#ifndef _POWERPC_PERF_CALLCHAIN_H
#define _POWERPC_PERF_CALLCHAIN_H

void perf_callchain_user_64(struct perf_callchain_entry_ctx *entry,
			    struct pt_regs *regs);
void perf_callchain_user_32(struct perf_callchain_entry_ctx *entry,
			    struct pt_regs *regs);

static inline bool invalid_user_sp(unsigned long sp)
{
	unsigned long mask = is_32bit_task() ? 3 : 7;
	unsigned long top = STACK_TOP - (is_32bit_task() ? 16 : 32);

	return (!sp || (sp & mask) || (sp > top));
}

/*
 * On 32-bit we just access the address and let hash_page create a
 * HPTE if necessary, so there is no need to fall back to reading
 * the page tables.  Since this is called at interrupt level,
 * do_page_fault() won't treat a DSI as a page fault.
 */
static inline int __read_user_stack(const void __user *ptr, void *ret,
				    size_t size)
{
	unsigned long addr = (unsigned long)ptr;

	if (addr > TASK_SIZE - size || (addr & (size - 1)))
		return -EFAULT;

	return copy_from_user_nofault(ret, ptr, size);
}

#endif /* _POWERPC_PERF_CALLCHAIN_H */

Annotation

• Detected declarations: `function invalid_user_sp`, `function do_page_fault`.
• Atlas domain: Architecture Layer / arch/powerpc.
• 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.