[PATCH 2/4] net/bpf: refactor freeing of executable allocations
From: Ard Biesheuvel <hidden>
Date: 2018-11-17 18:57:26
Also in:
linux-mips, linuxppc-dev, lkml, netdev, sparclinux
Subsystem:
bpf jit for mips (32-bit and 64-bit), bpf jit for powerpc (32-bit and 64-bit), bpf jit for sparc (32-bit and 64-bit), bpf [core], bpf [general] (safe dynamic programs and tools), linux for powerpc (32-bit and 64-bit), mips, sparc + ultrasparc (sparc/sparc64), the rest · Maintainers:
Johan Almbladh, Paul Burton, Hari Bathini, Christophe Leroy, David S. Miller, Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko, Eduard Zingerman, Kumar Kartikeya Dwivedi, Madhavan Srinivasan, Michael Ellerman, Thomas Bogendoerfer, "David S. Miller", Andreas Larsson, Linus Torvalds
All arch overrides of the __weak bpf_jit_free() amount to the same thing: the allocated memory was never mapped read-only, and so it does not have to be remapped to read-write before being freed. So in preparation of permitting arches to serve allocations for BPF JIT programs from other regions than the module region, refactor the existing bpf_jit_free() implementations to use the shared code where possible, and only specialize the remap and free operations. Signed-off-by: Ard Biesheuvel <redacted> --- arch/mips/net/bpf_jit.c | 7 ++----- arch/powerpc/net/bpf_jit_comp.c | 7 ++----- arch/powerpc/net/bpf_jit_comp64.c | 9 +++------ arch/sparc/net/bpf_jit_comp_32.c | 7 ++----- kernel/bpf/core.c | 15 +++++---------- 5 files changed, 14 insertions(+), 31 deletions(-)
diff --git a/arch/mips/net/bpf_jit.c b/arch/mips/net/bpf_jit.c
index 1b69897274a1..5696bd7dccc7 100644
--- a/arch/mips/net/bpf_jit.c
+++ b/arch/mips/net/bpf_jit.c@@ -1261,10 +1261,7 @@ void bpf_jit_compile(struct bpf_prog *fp) kfree(ctx.offsets); } -void bpf_jit_free(struct bpf_prog *fp) +void bpf_jit_binary_free(struct bpf_binary_header *hdr) { - if (fp->jited) - bpf_jit_binary_free(bpf_jit_binary_hdr(fp)); - - bpf_prog_unlock_free(fp); + module_memfree(hdr); }
diff --git a/arch/powerpc/net/bpf_jit_comp.c b/arch/powerpc/net/bpf_jit_comp.c
index a1ea1ea6b40d..5b5ce4a1b44b 100644
--- a/arch/powerpc/net/bpf_jit_comp.c
+++ b/arch/powerpc/net/bpf_jit_comp.c@@ -680,10 +680,7 @@ void bpf_jit_compile(struct bpf_prog *fp) return; } -void bpf_jit_free(struct bpf_prog *fp) +void bpf_jit_binary_free(struct bpf_binary_header *hdr) { - if (fp->jited) - bpf_jit_binary_free(bpf_jit_binary_hdr(fp)); - - bpf_prog_unlock_free(fp); + module_memfree(hdr); }
diff --git a/arch/powerpc/net/bpf_jit_comp64.c b/arch/powerpc/net/bpf_jit_comp64.c
index 84c8f013a6c6..f64f1294bd62 100644
--- a/arch/powerpc/net/bpf_jit_comp64.c
+++ b/arch/powerpc/net/bpf_jit_comp64.c@@ -1021,11 +1021,8 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *fp) return fp; } -/* Overriding bpf_jit_free() as we don't set images read-only. */ -void bpf_jit_free(struct bpf_prog *fp) +/* Overriding bpf_jit_binary_free() as we don't set images read-only. */ +void bpf_jit_binary_free(struct bpf_binary_header *hdr) { - if (fp->jited) - bpf_jit_binary_free(bpf_jit_binary_hdr(fp)); - - bpf_prog_unlock_free(fp); + module_memfree(hdr); }
diff --git a/arch/sparc/net/bpf_jit_comp_32.c b/arch/sparc/net/bpf_jit_comp_32.c
index 01bda6bc9e7f..589950d152cc 100644
--- a/arch/sparc/net/bpf_jit_comp_32.c
+++ b/arch/sparc/net/bpf_jit_comp_32.c@@ -756,10 +756,7 @@ cond_branch: f_offset = addrs[i + filter[i].jf]; return; } -void bpf_jit_free(struct bpf_prog *fp) +void bpf_jit_binary_free(struct bpf_binary_header *hdr) { - if (fp->jited) - bpf_jit_binary_free(bpf_jit_binary_hdr(fp)); - - bpf_prog_unlock_free(fp); + module_memfree(hdr); }
diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c
index 1a796e0799ec..29f766dac203 100644
--- a/kernel/bpf/core.c
+++ b/kernel/bpf/core.c@@ -646,25 +646,20 @@ bpf_jit_binary_alloc(unsigned int proglen, u8 **image_ptr, return hdr; } -void bpf_jit_binary_free(struct bpf_binary_header *hdr) +void __weak bpf_jit_binary_free(struct bpf_binary_header *hdr) { - u32 pages = hdr->pages; - + bpf_jit_binary_unlock_ro(hdr); module_memfree(hdr); - bpf_jit_uncharge_modmem(pages); } -/* This symbol is only overridden by archs that have different - * requirements than the usual eBPF JITs, f.e. when they only - * implement cBPF JIT, do not set images read-only, etc. - */ -void __weak bpf_jit_free(struct bpf_prog *fp) +void bpf_jit_free(struct bpf_prog *fp) { if (fp->jited) { struct bpf_binary_header *hdr = bpf_jit_binary_hdr(fp); + u32 pages = hdr->pages; - bpf_jit_binary_unlock_ro(hdr); bpf_jit_binary_free(hdr); + bpf_jit_uncharge_modmem(pages); WARN_ON_ONCE(!bpf_prog_kallsyms_verify_off(fp)); }
--
2.17.1