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-rw-r--r--kernel/bpf/hashtab.c30
-rw-r--r--tools/testing/selftests/bpf/prog_tests/map_init.c214
-rw-r--r--tools/testing/selftests/bpf/progs/test_map_init.c33
3 files changed, 275 insertions, 2 deletions
diff --git a/kernel/bpf/hashtab.c b/kernel/bpf/hashtab.c
index 1815e97d4c9c..1fccba6e88c4 100644
--- a/kernel/bpf/hashtab.c
+++ b/kernel/bpf/hashtab.c
@@ -821,6 +821,32 @@ static void pcpu_copy_value(struct bpf_htab *htab, void __percpu *pptr,
}
}
+static void pcpu_init_value(struct bpf_htab *htab, void __percpu *pptr,
+ void *value, bool onallcpus)
+{
+ /* When using prealloc and not setting the initial value on all cpus,
+ * zero-fill element values for other cpus (just as what happens when
+ * not using prealloc). Otherwise, bpf program has no way to ensure
+ * known initial values for cpus other than current one
+ * (onallcpus=false always when coming from bpf prog).
+ */
+ if (htab_is_prealloc(htab) && !onallcpus) {
+ u32 size = round_up(htab->map.value_size, 8);
+ int current_cpu = raw_smp_processor_id();
+ int cpu;
+
+ for_each_possible_cpu(cpu) {
+ if (cpu == current_cpu)
+ bpf_long_memcpy(per_cpu_ptr(pptr, cpu), value,
+ size);
+ else
+ memset(per_cpu_ptr(pptr, cpu), 0, size);
+ }
+ } else {
+ pcpu_copy_value(htab, pptr, value, onallcpus);
+ }
+}
+
static bool fd_htab_map_needs_adjust(const struct bpf_htab *htab)
{
return htab->map.map_type == BPF_MAP_TYPE_HASH_OF_MAPS &&
@@ -891,7 +917,7 @@ static struct htab_elem *alloc_htab_elem(struct bpf_htab *htab, void *key,
}
}
- pcpu_copy_value(htab, pptr, value, onallcpus);
+ pcpu_init_value(htab, pptr, value, onallcpus);
if (!prealloc)
htab_elem_set_ptr(l_new, key_size, pptr);
@@ -1183,7 +1209,7 @@ static int __htab_lru_percpu_map_update_elem(struct bpf_map *map, void *key,
pcpu_copy_value(htab, htab_elem_get_ptr(l_old, key_size),
value, onallcpus);
} else {
- pcpu_copy_value(htab, htab_elem_get_ptr(l_new, key_size),
+ pcpu_init_value(htab, htab_elem_get_ptr(l_new, key_size),
value, onallcpus);
hlist_nulls_add_head_rcu(&l_new->hash_node, head);
l_new = NULL;
diff --git a/tools/testing/selftests/bpf/prog_tests/map_init.c b/tools/testing/selftests/bpf/prog_tests/map_init.c
new file mode 100644
index 000000000000..14a31109dd0e
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/map_init.c
@@ -0,0 +1,214 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Copyright (c) 2020 Tessares SA <http://www.tessares.net> */
+
+#include <test_progs.h>
+#include "test_map_init.skel.h"
+
+#define TEST_VALUE 0x1234
+#define FILL_VALUE 0xdeadbeef
+
+static int nr_cpus;
+static int duration;
+
+typedef unsigned long long map_key_t;
+typedef unsigned long long map_value_t;
+typedef struct {
+ map_value_t v; /* padding */
+} __bpf_percpu_val_align pcpu_map_value_t;
+
+
+static int map_populate(int map_fd, int num)
+{
+ pcpu_map_value_t value[nr_cpus];
+ int i, err;
+ map_key_t key;
+
+ for (i = 0; i < nr_cpus; i++)
+ bpf_percpu(value, i) = FILL_VALUE;
+
+ for (key = 1; key <= num; key++) {
+ err = bpf_map_update_elem(map_fd, &key, value, BPF_NOEXIST);
+ if (!ASSERT_OK(err, "bpf_map_update_elem"))
+ return -1;
+ }
+
+ return 0;
+}
+
+static struct test_map_init *setup(enum bpf_map_type map_type, int map_sz,
+ int *map_fd, int populate)
+{
+ struct test_map_init *skel;
+ int err;
+
+ skel = test_map_init__open();
+ if (!ASSERT_OK_PTR(skel, "skel_open"))
+ return NULL;
+
+ err = bpf_map__set_type(skel->maps.hashmap1, map_type);
+ if (!ASSERT_OK(err, "bpf_map__set_type"))
+ goto error;
+
+ err = bpf_map__set_max_entries(skel->maps.hashmap1, map_sz);
+ if (!ASSERT_OK(err, "bpf_map__set_max_entries"))
+ goto error;
+
+ err = test_map_init__load(skel);
+ if (!ASSERT_OK(err, "skel_load"))
+ goto error;
+
+ *map_fd = bpf_map__fd(skel->maps.hashmap1);
+ if (CHECK(*map_fd < 0, "bpf_map__fd", "failed\n"))
+ goto error;
+
+ err = map_populate(*map_fd, populate);
+ if (!ASSERT_OK(err, "map_populate"))
+ goto error_map;
+
+ return skel;
+
+error_map:
+ close(*map_fd);
+error:
+ test_map_init__destroy(skel);
+ return NULL;
+}
+
+/* executes bpf program that updates map with key, value */
+static int prog_run_insert_elem(struct test_map_init *skel, map_key_t key,
+ map_value_t value)
+{
+ struct test_map_init__bss *bss;
+
+ bss = skel->bss;
+
+ bss->inKey = key;
+ bss->inValue = value;
+ bss->inPid = getpid();
+
+ if (!ASSERT_OK(test_map_init__attach(skel), "skel_attach"))
+ return -1;
+
+ /* Let tracepoint trigger */
+ syscall(__NR_getpgid);
+
+ test_map_init__detach(skel);
+
+ return 0;
+}
+
+static int check_values_one_cpu(pcpu_map_value_t *value, map_value_t expected)
+{
+ int i, nzCnt = 0;
+ map_value_t val;
+
+ for (i = 0; i < nr_cpus; i++) {
+ val = bpf_percpu(value, i);
+ if (val) {
+ if (CHECK(val != expected, "map value",
+ "unexpected for cpu %d: 0x%llx\n", i, val))
+ return -1;
+ nzCnt++;
+ }
+ }
+
+ if (CHECK(nzCnt != 1, "map value", "set for %d CPUs instead of 1!\n",
+ nzCnt))
+ return -1;
+
+ return 0;
+}
+
+/* Add key=1 elem with values set for all CPUs
+ * Delete elem key=1
+ * Run bpf prog that inserts new key=1 elem with value=0x1234
+ * (bpf prog can only set value for current CPU)
+ * Lookup Key=1 and check value is as expected for all CPUs:
+ * value set by bpf prog for one CPU, 0 for all others
+ */
+static void test_pcpu_map_init(void)
+{
+ pcpu_map_value_t value[nr_cpus];
+ struct test_map_init *skel;
+ int map_fd, err;
+ map_key_t key;
+
+ /* max 1 elem in map so insertion is forced to reuse freed entry */
+ skel = setup(BPF_MAP_TYPE_PERCPU_HASH, 1, &map_fd, 1);
+ if (!ASSERT_OK_PTR(skel, "prog_setup"))
+ return;
+
+ /* delete element so the entry can be re-used*/
+ key = 1;
+ err = bpf_map_delete_elem(map_fd, &key);
+ if (!ASSERT_OK(err, "bpf_map_delete_elem"))
+ goto cleanup;
+
+ /* run bpf prog that inserts new elem, re-using the slot just freed */
+ err = prog_run_insert_elem(skel, key, TEST_VALUE);
+ if (!ASSERT_OK(err, "prog_run_insert_elem"))
+ goto cleanup;
+
+ /* check that key=1 was re-created by bpf prog */
+ err = bpf_map_lookup_elem(map_fd, &key, value);
+ if (!ASSERT_OK(err, "bpf_map_lookup_elem"))
+ goto cleanup;
+
+ /* and has expected values */
+ check_values_one_cpu(value, TEST_VALUE);
+
+cleanup:
+ test_map_init__destroy(skel);
+}
+
+/* Add key=1 and key=2 elems with values set for all CPUs
+ * Run bpf prog that inserts new key=3 elem
+ * (only for current cpu; other cpus should have initial value = 0)
+ * Lookup Key=1 and check value is as expected for all CPUs
+ */
+static void test_pcpu_lru_map_init(void)
+{
+ pcpu_map_value_t value[nr_cpus];
+ struct test_map_init *skel;
+ int map_fd, err;
+ map_key_t key;
+
+ /* Set up LRU map with 2 elements, values filled for all CPUs.
+ * With these 2 elements, the LRU map is full
+ */
+ skel = setup(BPF_MAP_TYPE_LRU_PERCPU_HASH, 2, &map_fd, 2);
+ if (!ASSERT_OK_PTR(skel, "prog_setup"))
+ return;
+
+ /* run bpf prog that inserts new key=3 element, re-using LRU slot */
+ key = 3;
+ err = prog_run_insert_elem(skel, key, TEST_VALUE);
+ if (!ASSERT_OK(err, "prog_run_insert_elem"))
+ goto cleanup;
+
+ /* check that key=3 replaced one of earlier elements */
+ err = bpf_map_lookup_elem(map_fd, &key, value);
+ if (!ASSERT_OK(err, "bpf_map_lookup_elem"))
+ goto cleanup;
+
+ /* and has expected values */
+ check_values_one_cpu(value, TEST_VALUE);
+
+cleanup:
+ test_map_init__destroy(skel);
+}
+
+void test_map_init(void)
+{
+ nr_cpus = bpf_num_possible_cpus();
+ if (nr_cpus <= 1) {
+ printf("%s:SKIP: >1 cpu needed for this test\n", __func__);
+ test__skip();
+ return;
+ }
+
+ if (test__start_subtest("pcpu_map_init"))
+ test_pcpu_map_init();
+ if (test__start_subtest("pcpu_lru_map_init"))
+ test_pcpu_lru_map_init();
+}
diff --git a/tools/testing/selftests/bpf/progs/test_map_init.c b/tools/testing/selftests/bpf/progs/test_map_init.c
new file mode 100644
index 000000000000..c89d28ead673
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/test_map_init.c
@@ -0,0 +1,33 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2020 Tessares SA <http://www.tessares.net> */
+
+#include "vmlinux.h"
+#include <bpf/bpf_helpers.h>
+
+__u64 inKey = 0;
+__u64 inValue = 0;
+__u32 inPid = 0;
+
+struct {
+ __uint(type, BPF_MAP_TYPE_PERCPU_HASH);
+ __uint(max_entries, 2);
+ __type(key, __u64);
+ __type(value, __u64);
+} hashmap1 SEC(".maps");
+
+
+SEC("tp/syscalls/sys_enter_getpgid")
+int sysenter_getpgid(const void *ctx)
+{
+ /* Just do it for once, when called from our own test prog. This
+ * ensures the map value is only updated for a single CPU.
+ */
+ int cur_pid = bpf_get_current_pid_tgid() >> 32;
+
+ if (cur_pid == inPid)
+ bpf_map_update_elem(&hashmap1, &inKey, &inValue, BPF_NOEXIST);
+
+ return 0;
+}
+
+char _license[] SEC("license") = "GPL";
generated by cgit v1.2.3-58-ga151 (git 2.39.0) at 2024-11-30 08:53:36 +0000