You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
178 lines
8.0 KiB
178 lines
8.0 KiB
/*
|
|
* Copyright (C) 2020 The Android Open Source Project
|
|
*
|
|
* Licensed under the Apache License, Version 2.0 (the "License");
|
|
* you may not use this file except in compliance with the License.
|
|
* You may obtain a copy of the License at
|
|
*
|
|
* http://www.apache.org/licenses/LICENSE-2.0
|
|
*
|
|
* Unless required by applicable law or agreed to in writing, software
|
|
* distributed under the License is distributed on an "AS IS" BASIS,
|
|
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
* See the License for the specific language governing permissions and
|
|
* limitations under the License.
|
|
*/
|
|
|
|
#pragma once
|
|
|
|
/* This file is separate because it's included both by eBPF programs (via include
|
|
* in bpf_helpers.h) and directly by the boot time bpfloader (Loader.cpp).
|
|
*/
|
|
|
|
#include <linux/bpf.h>
|
|
|
|
// Pull in AID_* constants from //system/core/libcutils/include/private/android_filesystem_config.h
|
|
#include <private/android_filesystem_config.h>
|
|
|
|
/******************************************************************************
|
|
* *
|
|
* ! ! ! W A R N I N G ! ! ! *
|
|
* *
|
|
* CHANGES TO THESE STRUCTURE DEFINITIONS OUTSIDE OF AOSP/MASTER *WILL* BREAK *
|
|
* MAINLINE MODULE COMPATIBILITY *
|
|
* *
|
|
* AND THUS MAY RESULT IN YOUR DEVICE BRICKING AT SOME ARBITRARY POINT IN *
|
|
* THE FUTURE *
|
|
* *
|
|
* (and even in aosp/master you may only append new fields at the very end, *
|
|
* you may *never* delete fields, change their types, ordering, insert in *
|
|
* the middle, etc. If a mainline module using the old definition has *
|
|
* already shipped (which happens roughly monthly), then it's set in stone) *
|
|
* *
|
|
******************************************************************************/
|
|
|
|
// These are the values used if these fields are missing
|
|
#define DEFAULT_BPFLOADER_MIN_VER 0u // v0.0 (this is inclusive ie. >= v0.0)
|
|
#define DEFAULT_BPFLOADER_MAX_VER 0x10000u // v1.0 (this is exclusive ie. < v1.0)
|
|
#define DEFAULT_SIZEOF_BPF_MAP_DEF 32 // v0.0 struct: enum (uint sized) + 7 uint
|
|
#define DEFAULT_SIZEOF_BPF_PROG_DEF 20 // v0.0 struct: 4 uint + bool + 3 byte alignment pad
|
|
|
|
/*
|
|
* The bpf_{map,prog}_def structures are compiled for different architectures.
|
|
* Once by the BPF compiler for the BPF architecture, and once by a C++
|
|
* compiler for the native Android architecture for the bpfloader.
|
|
*
|
|
* For things to work, their layout must be the same between the two.
|
|
* The BPF architecture is platform independent ('64-bit LSB bpf').
|
|
* So this effectively means these structures must be the same layout
|
|
* on 5 architectures, all of them little endian:
|
|
* 64-bit BPF, x86_64, arm and 32-bit x86 and arm
|
|
*
|
|
* As such for any types we use inside of these structs we must make sure that
|
|
* the size and alignment are the same, so the same amount of padding is used.
|
|
*
|
|
* Currently we only use: bool, enum bpf_map_type and unsigned int.
|
|
* Additionally we use char for padding.
|
|
*
|
|
* !!! WARNING: HERE BE DRAGONS !!!
|
|
*
|
|
* Be particularly careful with 64-bit integers.
|
|
* You will need to manually override their alignment to 8 bytes.
|
|
*
|
|
* To quote some parts of https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69560
|
|
*
|
|
* Some types have weaker alignment requirements when they are structure members.
|
|
*
|
|
* unsigned long long on x86 is such a type.
|
|
*
|
|
* C distinguishes C11 _Alignof (the minimum alignment the type is guaranteed
|
|
* to have in all contexts, so 4, see min_align_of_type) from GNU C __alignof
|
|
* (the normal alignment of the type, so 8).
|
|
*
|
|
* alignof / _Alignof == minimum alignment required by target ABI
|
|
* __alignof / __alignof__ == preferred alignment
|
|
*
|
|
* When in a struct, apparently the minimum alignment is used.
|
|
*/
|
|
|
|
_Static_assert(sizeof(bool) == 1, "sizeof bool != 1");
|
|
_Static_assert(__alignof__(bool) == 1, "__alignof__ bool != 1");
|
|
_Static_assert(_Alignof(bool) == 1, "_Alignof bool != 1");
|
|
|
|
_Static_assert(sizeof(char) == 1, "sizeof char != 1");
|
|
_Static_assert(__alignof__(char) == 1, "__alignof__ char != 1");
|
|
_Static_assert(_Alignof(char) == 1, "_Alignof char != 1");
|
|
|
|
// This basically verifies that an enum is 'just' a 32-bit int
|
|
_Static_assert(sizeof(enum bpf_map_type) == 4, "sizeof enum bpf_map_type != 4");
|
|
_Static_assert(__alignof__(enum bpf_map_type) == 4, "__alignof__ enum bpf_map_type != 4");
|
|
_Static_assert(_Alignof(enum bpf_map_type) == 4, "_Alignof enum bpf_map_type != 4");
|
|
|
|
// Linux kernel requires sizeof(int) == 4, sizeof(void*) == sizeof(long), sizeof(long long) == 8
|
|
_Static_assert(sizeof(unsigned int) == 4, "sizeof unsigned int != 4");
|
|
_Static_assert(__alignof__(unsigned int) == 4, "__alignof__ unsigned int != 4");
|
|
_Static_assert(_Alignof(unsigned int) == 4, "_Alignof unsigned int != 4");
|
|
|
|
// We don't currently use any 64-bit types in these structs, so this is purely to document issue.
|
|
// Here sizeof & __alignof__ are consistent, but _Alignof is not: compile for 'aosp_cf_x86_phone'
|
|
_Static_assert(sizeof(unsigned long long) == 8, "sizeof unsigned long long != 8");
|
|
_Static_assert(__alignof__(unsigned long long) == 8, "__alignof__ unsigned long long != 8");
|
|
// BPF wants 8, but 32-bit x86 wants 4
|
|
//_Static_assert(_Alignof(unsigned long long) == 8, "_Alignof unsigned long long != 8");
|
|
|
|
/*
|
|
* Map structure to be used by Android eBPF C programs. The Android eBPF loader
|
|
* uses this structure from eBPF object to create maps at boot time.
|
|
*
|
|
* The eBPF C program should define structure in the maps section using
|
|
* SEC("maps") otherwise it will be ignored by the eBPF loader.
|
|
*
|
|
* For example:
|
|
* const struct bpf_map_def SEC("maps") mymap { .type=... , .key_size=... }
|
|
*
|
|
* See 'bpf_helpers.h' for helpful macros for eBPF program use.
|
|
*/
|
|
struct bpf_map_def {
|
|
enum bpf_map_type type;
|
|
unsigned int key_size;
|
|
unsigned int value_size;
|
|
unsigned int max_entries;
|
|
unsigned int map_flags;
|
|
|
|
// The following are not supported by the Android bpfloader:
|
|
// unsigned int inner_map_idx;
|
|
// unsigned int numa_node;
|
|
|
|
unsigned int uid; // uid_t
|
|
unsigned int gid; // gid_t
|
|
unsigned int mode; // mode_t
|
|
|
|
// The following fields were added in version 0.1
|
|
unsigned int bpfloader_min_ver; // if missing, defaults to 0, ie. v0.0
|
|
unsigned int bpfloader_max_ver; // if missing, defaults to 0x10000, ie. v1.0
|
|
|
|
// The following fields were added in version 0.2
|
|
// kernelVersion() must be >= min_kver and < max_kver
|
|
unsigned int min_kver;
|
|
unsigned int max_kver;
|
|
};
|
|
|
|
// This needs to be updated whenever the above structure definition is expanded.
|
|
_Static_assert(sizeof(struct bpf_map_def) == 48, "sizeof struct bpf_map_def != 48");
|
|
_Static_assert(__alignof__(struct bpf_map_def) == 4, "__alignof__ struct bpf_map_def != 4");
|
|
_Static_assert(_Alignof(struct bpf_map_def) == 4, "_Alignof struct bpf_map_def != 4");
|
|
|
|
struct bpf_prog_def {
|
|
unsigned int uid;
|
|
unsigned int gid;
|
|
|
|
// kernelVersion() must be >= min_kver and < max_kver
|
|
unsigned int min_kver;
|
|
unsigned int max_kver;
|
|
|
|
bool optional; // program section (ie. function) may fail to load, continue onto next func.
|
|
char pad0[3];
|
|
|
|
// The following fields were added in version 0.1
|
|
unsigned int bpfloader_min_ver; // if missing, defaults to 0, ie. v0.0
|
|
unsigned int bpfloader_max_ver; // if missing, defaults to 0x10000, ie. v1.0
|
|
|
|
// No new fields in version 0.2
|
|
};
|
|
|
|
// This needs to be updated whenever the above structure definition is expanded.
|
|
_Static_assert(sizeof(struct bpf_prog_def) == 28, "sizeof struct bpf_prog_def != 28");
|
|
_Static_assert(__alignof__(struct bpf_prog_def) == 4, "__alignof__ struct bpf_prog_def != 4");
|
|
_Static_assert(_Alignof(struct bpf_prog_def) == 4, "_Alignof struct bpf_prog_def != 4");
|