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author | Kui-Feng Lee <thinker.li@gmail.com> | 2024-01-19 14:49:59 -0800 |
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committer | Martin KaFai Lau <martin.lau@kernel.org> | 2024-01-23 16:37:44 -0800 |
commit | fcc2c1fb0651477c8ed78a3a293c175ccd70697a (patch) | |
tree | 5db50a9fefdd357c802c97bfe3962f1c6e0fee90 /kernel/bpf/syscall.c | |
parent | 689423db3bda2244c24db8a64de4cdb37be1de41 (diff) | |
download | linux-stable-fcc2c1fb0651477c8ed78a3a293c175ccd70697a.tar.gz linux-stable-fcc2c1fb0651477c8ed78a3a293c175ccd70697a.tar.bz2 linux-stable-fcc2c1fb0651477c8ed78a3a293c175ccd70697a.zip |
bpf: pass attached BTF to the bpf_struct_ops subsystem
Pass the fd of a btf from the userspace to the bpf() syscall, and then
convert the fd into a btf. The btf is generated from the module that
defines the target BPF struct_ops type.
In order to inform the kernel about the module that defines the target
struct_ops type, the userspace program needs to provide a btf fd for the
respective module's btf. This btf contains essential information on the
types defined within the module, including the target struct_ops type.
A btf fd must be provided to the kernel for struct_ops maps and for the bpf
programs attached to those maps.
In the case of the bpf programs, the attach_btf_obj_fd parameter is passed
as part of the bpf_attr and is converted into a btf. This btf is then
stored in the prog->aux->attach_btf field. Here, it just let the verifier
access attach_btf directly.
In the case of struct_ops maps, a btf fd is passed as value_type_btf_obj_fd
of bpf_attr. The bpf_struct_ops_map_alloc() function converts the fd to a
btf and stores it as st_map->btf. A flag BPF_F_VTYPE_BTF_OBJ_FD is added
for map_flags to indicate that the value of value_type_btf_obj_fd is set.
Signed-off-by: Kui-Feng Lee <thinker.li@gmail.com>
Link: https://lore.kernel.org/r/20240119225005.668602-9-thinker.li@gmail.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Diffstat (limited to 'kernel/bpf/syscall.c')
-rw-r--r-- | kernel/bpf/syscall.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index 55b458429705..f8124b3229e2 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -1123,7 +1123,7 @@ free_map_tab: return ret; } -#define BPF_MAP_CREATE_LAST_FIELD map_extra +#define BPF_MAP_CREATE_LAST_FIELD value_type_btf_obj_fd /* called via syscall */ static int map_create(union bpf_attr *attr) { |