[PATCH v4 bpf-next 4/7] bpf: add a pointer of bpf_binary_header to bpf_prog
From: Song Liu <song@kernel.org>
Date: 2022-01-19 23:06:51
Also in:
bpf, lkml
Subsystem:
bpf jit for x86 64-bit, bpf [core], bpf [general] (safe dynamic programs and tools), the rest, x86 architecture (32-bit and 64-bit) · Maintainers:
Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko, Eduard Zingerman, Kumar Kartikeya Dwivedi, Linus Torvalds, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen
With sub page allocation, we cannot simply use bpf_func & PAGE_MASK to find the bpf_binary_header. Add a pointer to struct bpf_prog to avoid this logic. Use this point for x86_64. If the pointer is not set by the jit engine, fall back to original logic. Signed-off-by: Song Liu <song@kernel.org> --- arch/x86/net/bpf_jit_comp.c | 2 ++ include/linux/filter.h | 10 ++++++++-- 2 files changed, 10 insertions(+), 2 deletions(-)
diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c
index ce1f86f245c9..fe4f08e25a1d 100644
--- a/arch/x86/net/bpf_jit_comp.c
+++ b/arch/x86/net/bpf_jit_comp.c@@ -2339,6 +2339,7 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog) if (header) bpf_jit_binary_free(header); prog = orig_prog; + header = NULL; goto out_addrs; } if (image) {
@@ -2406,6 +2407,7 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog) if (tmp_blinded) bpf_jit_prog_release_other(prog, prog == orig_prog ? tmp : orig_prog); + prog->hdr = header; return prog; }
diff --git a/include/linux/filter.h b/include/linux/filter.h
index 6cc1ebf1f840..6bb00f343cc5 100644
--- a/include/linux/filter.h
+++ b/include/linux/filter.h@@ -584,6 +584,7 @@ struct bpf_prog { const struct bpf_insn *insn); struct bpf_prog_aux *aux; /* Auxiliary fields */ struct sock_fprog_kern *orig_prog; /* Original BPF program */ + struct bpf_binary_header *hdr; /* Instructions for interpreter */ union { DECLARE_FLEX_ARRAY(struct sock_filter, insns);
@@ -893,9 +894,14 @@ static inline void bpf_jit_binary_lock_ro(struct bpf_binary_header *hdr) static inline struct bpf_binary_header * bpf_jit_binary_hdr(const struct bpf_prog *fp) { - unsigned long real_start = (unsigned long)fp->bpf_func; - unsigned long addr = real_start & PAGE_MASK; + unsigned long real_start; + unsigned long addr; + if (fp->hdr) + return fp->hdr; + + real_start = (unsigned long)fp->bpf_func; + addr = real_start & PAGE_MASK; return (void *)addr; }
--
2.30.2