[PATCH v2 3/4] bpf: switch to new vmalloc vfree flags
From: Rick Edgecombe <rick.p.edgecombe@intel.com>
Date: 2018-12-12 00:12:30
Also in:
linux-mm, lkml
Subsystem:
bpf [core], bpf [general] (safe dynamic programs and tools), the rest · Maintainers:
Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko, Eduard Zingerman, Kumar Kartikeya Dwivedi, Linus Torvalds
This switches to use the new vmalloc flags to control freeing memory with special permissions. Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com> --- include/linux/filter.h | 26 ++++++++++++-------------- kernel/bpf/core.c | 1 - 2 files changed, 12 insertions(+), 15 deletions(-)
diff --git a/include/linux/filter.h b/include/linux/filter.h
index 795ff0b869bb..2aeb93d3337d 100644
--- a/include/linux/filter.h
+++ b/include/linux/filter.h@@ -20,6 +20,7 @@ #include <linux/set_memory.h> #include <linux/kallsyms.h> #include <linux/if_vlan.h> +#include <linux/vmalloc.h> #include <net/sch_generic.h>
@@ -487,7 +488,6 @@ struct bpf_prog { u16 pages; /* Number of allocated pages */ u16 jited:1, /* Is our filter JIT'ed? */ jit_requested:1,/* archs need to JIT the prog */ - undo_set_mem:1, /* Passed set_memory_ro() checkpoint */ gpl_compatible:1, /* Is filter GPL compatible? */ cb_access:1, /* Is control block accessed? */ dst_needed:1, /* Do we need dst entry? */
@@ -699,24 +699,23 @@ bpf_ctx_narrow_access_ok(u32 off, u32 size, u32 size_default) static inline void bpf_prog_lock_ro(struct bpf_prog *fp) { - fp->undo_set_mem = 1; - set_memory_ro((unsigned long)fp, fp->pages); -} + struct vm_struct *vm = find_vm_area(fp); -static inline void bpf_prog_unlock_ro(struct bpf_prog *fp) -{ - if (fp->undo_set_mem) - set_memory_rw((unsigned long)fp, fp->pages); + if (vm) + vm->flags |= VM_HAS_SPECIAL_PERMS; + set_memory_ro((unsigned long)fp, fp->pages); } static inline void bpf_jit_binary_lock_ro(struct bpf_binary_header *hdr) { - set_memory_ro((unsigned long)hdr, hdr->pages); -} + struct vm_struct *vm = find_vm_area(hdr); -static inline void bpf_jit_binary_unlock_ro(struct bpf_binary_header *hdr) -{ - set_memory_rw((unsigned long)hdr, hdr->pages); + if (vm) { + vm->flags |= VM_HAS_SPECIAL_PERMS; + vm->flags |= VM_IMMEDIATE_UNMAP; + } + + set_memory_ro((unsigned long)hdr, hdr->pages); } static inline struct bpf_binary_header *
@@ -746,7 +745,6 @@ void __bpf_prog_free(struct bpf_prog *fp); static inline void bpf_prog_unlock_free(struct bpf_prog *fp) { - bpf_prog_unlock_ro(fp); __bpf_prog_free(fp); }
diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c
index b1a3545d0ec8..bd3efd7ce526 100644
--- a/kernel/bpf/core.c
+++ b/kernel/bpf/core.c@@ -663,7 +663,6 @@ void __weak bpf_jit_free(struct bpf_prog *fp) if (fp->jited) { struct bpf_binary_header *hdr = bpf_jit_binary_hdr(fp); - bpf_jit_binary_unlock_ro(hdr); bpf_jit_binary_free(hdr); WARN_ON_ONCE(!bpf_prog_kallsyms_verify_off(fp));
--
2.17.1