bpf: Fix percpu address space issues

In arraymap.c:

In bpf_array_map_seq_start() and bpf_array_map_seq_next()
cast return values from the __percpu address space to
the generic address space via uintptr_t [1].

Correct the declaration of pptr pointer in __bpf_array_map_seq_show()
to void __percpu * and cast the value from the generic address
space to the __percpu address space via uintptr_t [1].

In hashtab.c:

Assign the return value from bpf_mem_cache_alloc() to void pointer
and cast the value to void __percpu ** (void pointer to percpu void
pointer) before dereferencing.

In memalloc.c:

Explicitly declare __percpu variables.

Cast obj to void __percpu **.

In helpers.c:

Cast ptr in BPF_CALL_1 and BPF_CALL_2 from generic address space
to __percpu address space via const uintptr_t [1].

Found by GCC's named address space checks.

There were no changes in the resulting object files.

[1] https://sparse.docs.kernel.org/en/latest/annotations.html#address-space-name

Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: Martin KaFai Lau <martin.lau@linux.dev>
Cc: Eduard Zingerman <eddyz87@gmail.com>
Cc: Song Liu <song@kernel.org>
Cc: Yonghong Song <yonghong.song@linux.dev>
Cc: John Fastabend <john.fastabend@gmail.com>
Cc: KP Singh <kpsingh@kernel.org>
Cc: Stanislav Fomichev <sdf@fomichev.me>
Cc: Hao Luo <haoluo@google.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20240811161414.56744-1-ubizjak@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

1 files changed, 4 insertions, 4 deletions

diff --git a/kernel/bpf/arraymap.c b/kernel/bpf/arraymap.c
index 188e3c2effb2..a43e62e2a8bb 100644
--- a/kernel/bpf/arraymap.c
+++ b/kernel/bpf/arraymap.c
@@ -600,7 +600,7 @@ static void *bpf_array_map_seq_start(struct seq_file *seq, loff_t *pos)
 	array = container_of(map, struct bpf_array, map);
 	index = info->index & array->index_mask;
 	if (info->percpu_value_buf)
-	       return array->pptrs[index];
+		return (void *)(uintptr_t)array->pptrs[index];
 	return array_map_elem_ptr(array, index);
 }
 
@@ -619,7 +619,7 @@ static void *bpf_array_map_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 	array = container_of(map, struct bpf_array, map);
 	index = info->index & array->index_mask;
 	if (info->percpu_value_buf)
-	       return array->pptrs[index];
+		return (void *)(uintptr_t)array->pptrs[index];
 	return array_map_elem_ptr(array, index);
 }
 
@@ -632,7 +632,7 @@ static int __bpf_array_map_seq_show(struct seq_file *seq, void *v)
 	struct bpf_iter_meta meta;
 	struct bpf_prog *prog;
 	int off = 0, cpu = 0;
-	void __percpu **pptr;
+	void __percpu *pptr;
 	u32 size;
 
 	meta.seq = seq;
@@ -648,7 +648,7 @@ static int __bpf_array_map_seq_show(struct seq_file *seq, void *v)
 		if (!info->percpu_value_buf) {
 			ctx.value = v;
 		} else {
-			pptr = v;
+			pptr = (void __percpu *)(uintptr_t)v;
 			size = array->elem_size;
 			for_each_possible_cpu(cpu) {
 				copy_map_value_long(map, info->percpu_value_buf + off,