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| author | Kumar Kartikeya Dwivedi <memxor@gmail.com> | 2025-09-23 11:01:49 +0000 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2025-09-23 12:00:22 -0700 |
| commit | a91ae3c89311648cbaa9b46b860e4f76004a24b8 (patch) | |
| tree | eb70a89b901b3de88d52d81bc9536db2a337c5fc /include | |
| parent | Merge branch 'bpf-introduce-deferred-task-context-execution' (diff) | |
| download | linux-a91ae3c89311648cbaa9b46b860e4f76004a24b8.tar.gz linux-a91ae3c89311648cbaa9b46b860e4f76004a24b8.zip | |
bpf, x86: Add support for signed arena loads
Currently, signed load instructions into arena memory are unsupported.
The compiler is free to generate these, and on GCC-14 we see a
corresponding error when it happens. The hurdle in supporting them is
deciding which unused opcode to use to mark them for the JIT's own
consumption. After much thinking, it appears 0xc0 / BPF_NOSPEC can be
combined with load instructions to identify signed arena loads. Use
this to recognize and JIT them appropriately, and remove the verifier
side limitation on the program if the JIT supports them.
Co-developed-by: Puranjay Mohan <puranjay@kernel.org>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Puranjay Mohan <puranjay@kernel.org>
Link: https://lore.kernel.org/r/20250923110157.18326-2-puranjay@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/filter.h | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/include/linux/filter.h b/include/linux/filter.h index 4241a885975f..f5c859b8131a 100644 --- a/include/linux/filter.h +++ b/include/linux/filter.h @@ -78,6 +78,9 @@ struct ctl_table_header; /* unused opcode to mark special atomic instruction */ #define BPF_PROBE_ATOMIC 0xe0 +/* unused opcode to mark special ldsx instruction. Same as BPF_NOSPEC */ +#define BPF_PROBE_MEM32SX 0xc0 + /* unused opcode to mark call to interpreter with arguments */ #define BPF_CALL_ARGS 0xe0 |