forked from Minki/linux
3fc32f40c4
Implement support for TYPE_EXISTS/TYPE_SIZE/TYPE_ID_LOCAL/TYPE_ID_REMOTE relocations. These are examples of type-based relocations, as opposed to field-based relocations supported already. The difference is that they are calculating relocation values based on the type itself, not a field within a struct/union. Type-based relos have slightly different semantics when matching local types to kernel target types, see comments in bpf_core_types_are_compat() for details. Their behavior on failure to find target type in kernel BTF also differs. Instead of "poisoning" relocatable instruction and failing load subsequently in kernel, they return 0 (which is rarely a valid return result, so user BPF code can use that to detect success/failure of the relocation and deal with it without extra "guarding" relocations). Also, it's always possible to check existence of the type in target kernel with TYPE_EXISTS relocation, similarly to a field-based FIELD_EXISTS. TYPE_ID_LOCAL relocation is a bit special in that it always succeeds (barring any libbpf/Clang bugs) and resolved to BTF ID using **local** BTF info of BPF program itself. Tests in subsequent patches demonstrate the usage and semantics of new relocations. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Yonghong Song <yhs@fb.com> Link: https://lore.kernel.org/bpf/20200819194519.3375898-2-andriin@fb.com |
||
|---|---|---|
| .. | ||
| accounting | ||
| arch | ||
| bootconfig | ||
| bpf | ||
| build | ||
| cgroup | ||
| debugging | ||
| edid | ||
| firewire | ||
| firmware | ||
| gpio | ||
| hv | ||
| iio | ||
| include | ||
| io_uring | ||
| kvm/kvm_stat | ||
| laptop | ||
| leds | ||
| lib | ||
| memory-model | ||
| nfsd | ||
| objtool | ||
| pci | ||
| pcmcia | ||
| perf | ||
| power | ||
| scripts | ||
| spi | ||
| testing | ||
| thermal/tmon | ||
| time | ||
| usb | ||
| virtio | ||
| vm | ||
| wmi | ||
| Makefile | ||