This commit adds support for BPF dynamic code modification on the
LoongArch architecture:
1. Add bpf_arch_text_copy() for instruction block copying.
2. Add bpf_arch_text_poke() for runtime instruction patching.
3. Add bpf_arch_text_invalidate() for code invalidation.
On LoongArch, since symbol addresses in the direct mapping region can't
be reached via relative jump instructions from the paged mapping region,
we use the move_imm+jirl instruction pair as absolute jump instructions.
These require 2-5 instructions, so we reserve 5 NOP instructions in the
program as placeholders for function jumps.
The larch_insn_text_copy() function is solely used for BPF. And the use
of larch_insn_text_copy() requires PAGE_SIZE alignment. Currently, only
the size of the BPF trampoline is page-aligned.
Co-developed-by: George Guo <guodongtai@kylinos.cn>
Signed-off-by: George Guo <guodongtai@kylinos.cn>
Signed-off-by: Chenghao Duan <duanchenghao@kylinos.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: maoxiaochuan <maoxiaochuan@loongson.cn>
1. Rename the existing validate_code() to validate_ctx()
2. Factor out the code validation handling into a new helper
validate_code()
Then:
* validate_code() is used to check the validity of code.
* validate_ctx() is used to check both code validity and table entry
correctness.
The new validate_code() will be used in subsequent changes.
Reviewed-by: Hengqi Chen <hengqi.chen@gmail.com>
Co-developed-by: George Guo <guodongtai@kylinos.cn>
Signed-off-by: George Guo <guodongtai@kylinos.cn>
Signed-off-by: Chenghao Duan <duanchenghao@kylinos.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: maoxiaochuan <maoxiaochuan@loongson.cn>
Chenghao Duan