PCI: Add pci_irq_type() to query the allocated interrupt typegrafted

Add a helper that returns PCI_IRQ_MSIX, PCI_IRQ_MSI, or PCI_IRQ_INTX
based on the interrupt type the PCI core selected after
pci_alloc_irq_vectors().

Several drivers already open-code this check against pdev->msix_enabled
and pdev->msi_enabled, or even open code this helper [1].

A common helper avoids the duplication and keeps drivers from accessing
the bitfield directly (see also [2]).

Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Tested-by: John Hubbard <jhubbard@nvidia.com>
Link: https://elixir.bootlin.com/linux/v7.1/source/drivers/net/ethernet/aquantia/atlantic/aq_pci_func.c#L196 [1]
Inspired-by: John Hubbard <jhubbard@nvidia.com>
Link: https://lore.kernel.org/all/DKKG2QM3YJYB.Z2H2B2UXJ75N@kernel.org/ [2]
Reviewed-by: Gary Guo <gary@garyguo.net>
Link: https://patch.msgid.link/20260813165234.620555-5-dakr@kernel.org
[ Add missing pci_irq_type() stub for CONFIG_PCI=n. ]
Signed-off-by: Danilo Krummrich <dakr@kernel.org>

1 files changed, 84 insertions, 0 deletions

diff --git a/tools/perf/tests/openat-syscall.c b/tools/perf/tests/openat-syscall.c
new file mode 100644
index 000000000..b54cbe5f1
--- /dev/null
+++ b/tools/perf/tests/openat-syscall.c
@@ -0,0 +1,84 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <errno.h>
+#include <inttypes.h>
+#include <api/fs/tracing_path.h>
+#include <linux/err.h>
+#include <linux/string.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include "thread_map.h"
+#include "evsel.h"
+#include "debug.h"
+#include "tests.h"
+#include "util/counts.h"
+
+static int test__openat_syscall_event(struct test_suite *test __maybe_unused,
+				      int subtest __maybe_unused)
+{
+	int err = TEST_FAIL, fd;
+	struct evsel *evsel;
+	unsigned int nr_openat_calls = 111, i;
+	struct perf_thread_map *threads = thread_map__new_by_tid(getpid());
+	char sbuf[STRERR_BUFSIZE];
+	char errbuf[BUFSIZ];
+
+	if (threads == NULL) {
+		pr_debug("thread_map__new\n");
+		return TEST_FAIL;
+	}
+
+	evsel = evsel__newtp("syscalls", "sys_enter_openat");
+	if (IS_ERR(evsel)) {
+		tracing_path__strerror_open_tp(errno, errbuf, sizeof(errbuf), "syscalls", "sys_enter_openat");
+		pr_debug("%s\n", errbuf);
+		err = TEST_SKIP;
+		goto out_thread_map_delete;
+	}
+
+	if (evsel__open_per_thread(evsel, threads) < 0) {
+		pr_debug("failed to open counter: %s, "
+			 "tweak /proc/sys/kernel/perf_event_paranoid?\n",
+			 str_error_r(errno, sbuf, sizeof(sbuf)));
+		err = TEST_SKIP;
+		goto out_evsel_delete;
+	}
+
+	for (i = 0; i < nr_openat_calls; ++i) {
+		fd = openat(0, "/etc/passwd", O_RDONLY);
+		close(fd);
+	}
+
+	if (evsel__read_on_cpu(evsel, 0, 0) < 0) {
+		pr_debug("evsel__read_on_cpu\n");
+		goto out_close_fd;
+	}
+
+	if (perf_counts(evsel->counts, 0, 0)->val != nr_openat_calls) {
+		pr_debug("evsel__read_on_cpu: expected to intercept %d calls, got %" PRIu64 "\n",
+			 nr_openat_calls, perf_counts(evsel->counts, 0, 0)->val);
+		goto out_close_fd;
+	}
+
+	err = TEST_OK;
+out_close_fd:
+	perf_evsel__close_fd(&evsel->core);
+out_evsel_delete:
+	evsel__delete(evsel);
+out_thread_map_delete:
+	perf_thread_map__put(threads);
+	return err;
+}
+
+static struct test_case tests__openat_syscall_event[] = {
+	TEST_CASE_REASON("Detect openat syscall event",
+			 openat_syscall_event,
+			 "permissions"),
+	{	.name = NULL, }
+};
+
+struct test_suite suite__openat_syscall_event = {
+	.desc = "Detect openat syscall event",
+	.test_cases = tests__openat_syscall_event,
+};