From 7c6a469e3416fa23568c2395a3faa7dd6e376dcb Mon Sep 17 00:00:00 2001 From: Alexei Starovoitov Date: Tue, 15 Oct 2019 20:24:56 -0700 Subject: bpf: Add typecast to bpf helpers to help BTF generation When pahole converts dwarf to btf it emits only used types. Wrap existing bpf helper functions into typedef and use it in typecast to make gcc emits this type into dwarf. Then pahole will convert it to btf. The "btf_#name_of_helper" types will be used to figure out types of arguments of bpf helpers. The generated code before and after is the same. Only dwarf and btf sections are different. Signed-off-by: Alexei Starovoitov Signed-off-by: Daniel Borkmann Acked-by: Andrii Nakryiko Acked-by: John Fastabend Acked-by: Martin KaFai Lau Link: https://lore.kernel.org/bpf/20191016032505.2089704-3-ast@kernel.org --- include/linux/filter.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'include/linux/filter.h') diff --git a/include/linux/filter.h b/include/linux/filter.h index 2ce57645f3cd..d3d51d7aff2c 100644 --- a/include/linux/filter.h +++ b/include/linux/filter.h @@ -464,10 +464,11 @@ static inline bool insn_is_zext(const struct bpf_insn *insn) #define BPF_CALL_x(x, name, ...) \ static __always_inline \ u64 ____##name(__BPF_MAP(x, __BPF_DECL_ARGS, __BPF_V, __VA_ARGS__)); \ + typedef u64 (*btf_##name)(__BPF_MAP(x, __BPF_DECL_ARGS, __BPF_V, __VA_ARGS__)); \ u64 name(__BPF_REG(x, __BPF_DECL_REGS, __BPF_N, __VA_ARGS__)); \ u64 name(__BPF_REG(x, __BPF_DECL_REGS, __BPF_N, __VA_ARGS__)) \ { \ - return ____##name(__BPF_MAP(x,__BPF_CAST,__BPF_N,__VA_ARGS__));\ + return ((btf_##name)____##name)(__BPF_MAP(x,__BPF_CAST,__BPF_N,__VA_ARGS__));\ } \ static __always_inline \ u64 ____##name(__BPF_MAP(x, __BPF_DECL_ARGS, __BPF_V, __VA_ARGS__)) -- cgit v1.2.3 From 2a02759ef5f8a34792df22b41d5e10658fd7bbd3 Mon Sep 17 00:00:00 2001 From: Alexei Starovoitov Date: Tue, 15 Oct 2019 20:25:02 -0700 Subject: bpf: Add support for BTF pointers to interpreter Pointer to BTF object is a pointer to kernel object or NULL. The memory access in the interpreter has to be done via probe_kernel_read to avoid page faults. Signed-off-by: Alexei Starovoitov Signed-off-by: Daniel Borkmann Acked-by: Andrii Nakryiko Acked-by: Martin KaFai Lau Link: https://lore.kernel.org/bpf/20191016032505.2089704-9-ast@kernel.org --- include/linux/filter.h | 3 +++ 1 file changed, 3 insertions(+) (limited to 'include/linux/filter.h') diff --git a/include/linux/filter.h b/include/linux/filter.h index d3d51d7aff2c..22ebea2e64ea 100644 --- a/include/linux/filter.h +++ b/include/linux/filter.h @@ -65,6 +65,9 @@ struct ctl_table_header; /* unused opcode to mark special call to bpf_tail_call() helper */ #define BPF_TAIL_CALL 0xf0 +/* unused opcode to mark special load instruction. Same as BPF_ABS */ +#define BPF_PROBE_MEM 0x20 + /* unused opcode to mark call to interpreter with arguments */ #define BPF_CALL_ARGS 0xe0 -- cgit v1.2.3 From b7b3fc8dd95bc02bd30680da258e09dda55270db Mon Sep 17 00:00:00 2001 From: Ilya Leoshkevich Date: Fri, 15 Nov 2019 13:37:22 +0100 Subject: bpf: Support doubleword alignment in bpf_jit_binary_alloc Currently passing alignment greater than 4 to bpf_jit_binary_alloc does not work: in such cases it silently aligns only to 4 bytes. On s390, in order to load a constant from memory in a large (>512k) BPF program, one must use lgrl instruction, whose memory operand must be aligned on an 8-byte boundary. This patch makes it possible to request 8-byte alignment from bpf_jit_binary_alloc, and also makes it issue a warning when an unsupported alignment is requested. Signed-off-by: Ilya Leoshkevich Signed-off-by: Daniel Borkmann Link: https://lore.kernel.org/bpf/20191115123722.58462-1-iii@linux.ibm.com --- include/linux/filter.h | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) (limited to 'include/linux/filter.h') diff --git a/include/linux/filter.h b/include/linux/filter.h index 7a6f8f6f1da4..ad80e9c6111c 100644 --- a/include/linux/filter.h +++ b/include/linux/filter.h @@ -515,10 +515,12 @@ struct sock_fprog_kern { struct sock_filter *filter; }; +/* Some arches need doubleword alignment for their instructions and/or data */ +#define BPF_IMAGE_ALIGNMENT 8 + struct bpf_binary_header { u32 pages; - /* Some arches need word alignment for their instructions */ - u8 image[] __aligned(4); + u8 image[] __aligned(BPF_IMAGE_ALIGNMENT); }; struct bpf_prog { -- cgit v1.2.3 From a66886fe6c24ebeeb6dc10fbd9b75158029eacf7 Mon Sep 17 00:00:00 2001 From: Daniel Borkmann Date: Fri, 22 Nov 2019 21:07:57 +0100 Subject: bpf: Add initial poke descriptor table for jit images Add initial poke table data structures and management to the BPF prog that can later be used by JITs. Also add an instance of poke specific data for tail call maps; plan for later work is to extend this also for BPF static keys. Signed-off-by: Daniel Borkmann Signed-off-by: Alexei Starovoitov Acked-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/1db285ec2ea4207ee0455b3f8e191a4fc58b9ade.1574452833.git.daniel@iogearbox.net --- include/linux/filter.h | 10 ++++++++++ 1 file changed, 10 insertions(+) (limited to 'include/linux/filter.h') diff --git a/include/linux/filter.h b/include/linux/filter.h index ad80e9c6111c..796b60d8cc6c 100644 --- a/include/linux/filter.h +++ b/include/linux/filter.h @@ -952,6 +952,9 @@ void *bpf_jit_alloc_exec(unsigned long size); void bpf_jit_free_exec(void *addr); void bpf_jit_free(struct bpf_prog *fp); +int bpf_jit_add_poke_descriptor(struct bpf_prog *prog, + struct bpf_jit_poke_descriptor *poke); + int bpf_jit_get_func_addr(const struct bpf_prog *prog, const struct bpf_insn *insn, bool extra_pass, u64 *func_addr, bool *func_addr_fixed); @@ -1055,6 +1058,13 @@ static inline bool bpf_prog_ebpf_jited(const struct bpf_prog *fp) return false; } +static inline int +bpf_jit_add_poke_descriptor(struct bpf_prog *prog, + struct bpf_jit_poke_descriptor *poke) +{ + return -ENOTSUPP; +} + static inline void bpf_jit_free(struct bpf_prog *fp) { bpf_prog_unlock_free(fp); -- cgit v1.2.3 From b8cd76ca4ae34731d47cd6a876d912a08efcc240 Mon Sep 17 00:00:00 2001 From: Daniel Borkmann Date: Sat, 23 Nov 2019 21:37:31 +0100 Subject: bpf: Add bpf_jit_blinding_enabled for !CONFIG_BPF_JIT MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Add a definition of bpf_jit_blinding_enabled() when CONFIG_BPF_JIT is not set in order to fix a recent build regression: [...] CC kernel/bpf/verifier.o CC kernel/bpf/inode.o kernel/bpf/verifier.c: In function ‘fixup_bpf_calls’: kernel/bpf/verifier.c:9132:25: error: implicit declaration of function ‘bpf_jit_blinding_enabled’; did you mean ‘bpf_jit_kallsyms_enabled’? [-Werror=implicit-function-declaration] 9132 | bool expect_blinding = bpf_jit_blinding_enabled(prog); | ^~~~~~~~~~~~~~~~~~~~~~~~ | bpf_jit_kallsyms_enabled CC kernel/bpf/helpers.o CC kernel/bpf/hashtab.o [...] Fixes: d2e4c1e6c294 ("bpf: Constant map key tracking for prog array pokes") Reported-by: Jakub Sitnicki Reported-by: Andrii Nakryiko Signed-off-by: Daniel Borkmann Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/40baf8f3507cac4851a310578edfb98ce73b5605.1574541375.git.daniel@iogearbox.net --- include/linux/filter.h | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'include/linux/filter.h') diff --git a/include/linux/filter.h b/include/linux/filter.h index 796b60d8cc6c..1b1e8b8f88da 100644 --- a/include/linux/filter.h +++ b/include/linux/filter.h @@ -1053,6 +1053,11 @@ static inline bool ebpf_jit_enabled(void) return false; } +static inline bool bpf_jit_blinding_enabled(struct bpf_prog *prog) +{ + return false; +} + static inline bool bpf_prog_ebpf_jited(const struct bpf_prog *fp) { return false; -- cgit v1.2.3