Claude review: perf/core: out-of-line and export perf_allow_cpu/tracepoint()

[Claude Code Review Bot <claude-review@example.com>]

Patch Review

**Good:**

The out-of-line implementations are exact copies of the previous static inline bodies, preserving the distinct threshold levels and error codes:

```c
int perf_allow_cpu(void)
{
	if (sysctl_perf_event_paranoid > 0 && !perfmon_capable())
		return -EACCES;
	return security_perf_event_open(PERF_SECURITY_CPU);
}

int perf_allow_tracepoint(void)
{
	if (sysctl_perf_event_paranoid > -1 && !perfmon_capable())
		return -EPERM;
	return security_perf_event_open(PERF_SECURITY_TRACEPOINT);
}
```

The graduated thresholds (`> 0` for CPU, `> -1` for tracepoint, `> 1` for kernel in the existing code) and distinct error codes (`-EACCES` vs `-EPERM`) are all faithfully preserved.

**Good: !CONFIG_PERF_EVENTS stubs are complete.** The patch adds stubs for all three helpers:

```c
static inline int perf_allow_kernel(void)
{
	return perfmon_capable() ? 0 : -EACCES;
}
static inline int perf_allow_cpu(void)
{
	return perfmon_capable() ? 0 : -EACCES;
}
static inline int perf_allow_tracepoint(void)
{
	return perfmon_capable() ? 0 : -EPERM;
}
```

Note that `perf_allow_kernel()` didn't have a `!CONFIG_PERF_EVENTS` stub before this patch either -- the existing code declared it `extern` in the `CONFIG_PERF_EVENTS` block with no fallback. Adding it here is a bonus fix that makes the trio complete. The cover letter v2 changelog correctly attributes this to AI review feedback catching the build failure with `PERF_EVENTS=n`.

**Minor observation:** The stubs use `perfmon_capable()` as the fallback, which is a reasonable conservative default -- it requires `CAP_PERFMON` or `CAP_SYS_ADMIN`. The LSM hook is naturally unavailable without `CONFIG_PERF_EVENTS`, so this is the best approximation.

**Placement:** The new functions are placed in `kernel/events/core.c` right after the existing `perf_allow_kernel()` / `EXPORT_SYMBOL_GPL`, which is the natural location. No issues.

No problems with this patch.

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Generated by Claude Code Patch Reviewer