perf/x86/rapl: Fix the error checking order

After the commit b4943b8bfc41 ("perf/x86/rapl: Add core energy counter
support for AMD CPUs"), the default "perf record"/"perf top" command is
broken in systems where there isn't a PMU registered for type
PERF_TYPE_RAW.

This is due to the change in order of error checks in rapl_pmu_event_init()
Due to which we return -EINVAL instead of -ENOENT, when we reach here from
the fallback loop in perf_init_event().

Move the "PMU and event type match" back to the beginning of the function
so that we return -ENOENT early on.

Closes: https://lore.kernel.org/all/uv7mz6vew2bzgre5jdpmwldxljp5djzmuiksqdcdwipfm4zm7w@ribobcretidk/
Fixes: b4943b8bfc41 ("perf/x86/rapl: Add core energy counter support for AMD CPUs")
Reported-by: Koichiro Den <koichiro.den@canonical.com>
Signed-off-by: Dhananjay Ugwekar <dhananjay.ugwekar@amd.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20250129080513.30353-1-dhananjay.ugwekar@amd.com

diff --git a/arch/x86/events/rapl.c b/arch/x86/events/rapl.c
index d3bb3865c1b1faaff2456517a7a518b73bb21a82..4952faf03e82d9fae5d4a0a235de649ffb514062 100644 (file)
--- a/arch/x86/events/rapl.c
+++ b/arch/x86/events/rapl.c
@@ -370,6 +370,10 @@ static int rapl_pmu_event_init(struct perf_event *event)
        unsigned int rapl_pmu_idx;
        struct rapl_pmus *rapl_pmus;
 
+       /* only look at RAPL events */
+       if (event->attr.type != event->pmu->type)
+               return -ENOENT;
+
        /* unsupported modes and filters */
        if (event->attr.sample_period) /* no sampling */
                return -EINVAL;
@@ -387,10 +391,6 @@ static int rapl_pmu_event_init(struct perf_event *event)
        rapl_pmus_scope = rapl_pmus->pmu.scope;
 
        if (rapl_pmus_scope == PERF_PMU_SCOPE_PKG || rapl_pmus_scope == PERF_PMU_SCOPE_DIE) {
-               /* only look at RAPL package events */
-               if (event->attr.type != rapl_pmus_pkg->pmu.type)
-                       return -ENOENT;
-
                cfg = array_index_nospec((long)cfg, NR_RAPL_PKG_DOMAINS + 1);
                if (!cfg || cfg >= NR_RAPL_PKG_DOMAINS + 1)
                        return -EINVAL;
@@ -398,10 +398,6 @@ static int rapl_pmu_event_init(struct perf_event *event)
                bit = cfg - 1;
                event->hw.event_base = rapl_model->rapl_pkg_msrs[bit].msr;
        } else if (rapl_pmus_scope == PERF_PMU_SCOPE_CORE) {
-               /* only look at RAPL core events */
-               if (event->attr.type != rapl_pmus_core->pmu.type)
-                       return -ENOENT;
-
                cfg = array_index_nospec((long)cfg, NR_RAPL_CORE_DOMAINS + 1);
                if (!cfg || cfg >= NR_RAPL_PKG_DOMAINS + 1)
                        return -EINVAL;