linux-toradex.git/tools/lib/bpf/btf_dump.c, branch v5.8-rc1

libbpf: Handle GCC noreturn-turned-volatile quirk

2020-06-10T11:37:02+00:00

Handle a GCC quirk of emitting extra volatile modifier in DWARF (and
subsequently preserved in BTF by pahole) for function pointers marked as
__attribute__((noreturn)). This was the way to mark such functions before GCC
2.5 added noreturn attribute. Drop such func_proto modifiers, similarly to how
it's done for array (also to handle GCC quirk/bug).

Such volatile attribute is emitted by GCC only, so existing selftests can't
express such test. Simple repro is like this (compiled with GCC + BTF
generated by pahole):

  struct my_struct {
      void __attribute__((noreturn)) (*fn)(int);
  };
  struct my_struct a;

Without this fix, output will be:

struct my_struct {
    voidvolatile  (*fn)(int);
};

With the fix:

struct my_struct {
    void (*fn)(int);
};

Fixes: 351131b51c7a ("libbpf: add btf_dump API for BTF-to-C conversion")
Reported-by: Jean-Philippe Brucker 
Signed-off-by: Andrii Nakryiko 
Signed-off-by: Daniel Borkmann 
Tested-by: Jean-Philippe Brucker 
Link: https://lore.kernel.org/bpf/20200610052335.2862559-1-andriin@fb.com

libbpf: Remove unneeded semicolon in btf_dump_emit_type

2020-04-28T19:47:47+00:00

Fixes the following coccicheck warning:

 tools/lib/bpf/btf_dump.c:661:4-5: Unneeded semicolon

Reported-by: Hulk Robot 
Signed-off-by: Zou Wei 
Signed-off-by: Daniel Borkmann 
Link: https://lore.kernel.org/bpf/1588064829-70613-1-git-send-email-zou_wei@huawei.com

libbpf: Assume unsigned values for BTF_KIND_ENUM

2020-03-04T16:00:06+00:00

Currently, BTF_KIND_ENUM type doesn't record whether enum values should be
interpreted as signed or unsigned. In Linux, most enums are unsigned, though,
so interpreting them as unsigned matches real world better.

Change btf_dump test case to test maximum 32-bit value, instead of negative
value.

Signed-off-by: Andrii Nakryiko 
Signed-off-by: Daniel Borkmann 
Link: https://lore.kernel.org/bpf/20200303003233.3496043-3-andriin@fb.com

libbpf: Fix handling of optional field_name in btf_dump__emit_type_decl

2020-03-04T00:41:36+00:00

Internal functions, used by btf_dump__emit_type_decl(), assume field_name is
never going to be NULL. Ensure it's always the case.

Fixes: 9f81654eebe8 ("libbpf: Expose BTF-to-C type declaration emitting API")
Signed-off-by: Andrii Nakryiko 
Signed-off-by: Alexei Starovoitov 
Link: https://lore.kernel.org/bpf/20200303180800.3303471-1-andriin@fb.com

libbpf: Fix error handling bug in btf_dump__new

2020-01-17T16:33:17+00:00

Fix missing jump to error handling in btf_dump__new, found by Coverity static
code analysis.

Fixes: 9f81654eebe8 ("libbpf: Expose BTF-to-C type declaration emitting API")
Signed-off-by: Andrii Nakryiko 
Signed-off-by: Alexei Starovoitov 
Link: https://lore.kernel.org/bpf/20200117060801.1311525-2-andriin@fb.com

libbpf: Poison kernel-only integer types

2020-01-10T18:38:00+00:00

It's been a recurring issue with types like u32 slipping into libbpf source
code accidentally. This is not detected during builds inside kernel source
tree, but becomes a compilation error in libbpf's Github repo. Libbpf is
supposed to use only __{s,u}{8,16,32,64} typedefs, so poison {s,u}{8,16,32,64}
explicitly in every .c file. Doing that in a bit more centralized way, e.g.,
inside libbpf_internal.h breaks selftests, which are both using kernel u32 and
libbpf_internal.h.

This patch also fixes a new u32 occurence in libbpf.c, added recently.

Fixes: 590a00888250 ("bpf: libbpf: Add STRUCT_OPS support")
Signed-off-by: Andrii Nakryiko 
Signed-off-by: Alexei Starovoitov 
Acked-by: Martin KaFai Lau 
Link: https://lore.kernel.org/bpf/20200110181916.271446-1-andriin@fb.com

libbpf: Expose BTF-to-C type declaration emitting API

2019-12-15T23:58:05+00:00

Expose API that allows to emit type declaration and field/variable definition
(if optional field name is specified) in valid C syntax for any provided BTF
type. This is going to be used by bpftool when emitting data section layout as
a struct. As part of making this API useful in a stand-alone fashion, move
initialization of some of the internal btf_dump state to earlier phase.

Signed-off-by: Andrii Nakryiko 
Signed-off-by: Alexei Starovoitov 
Acked-by: Martin KaFai Lau 
Link: https://lore.kernel.org/bpf/20191214014341.3442258-8-andriin@fb.com

libbpf: Expose btf__align_of() API

2019-12-15T23:58:05+00:00

Expose BTF API that calculates type alignment requirements.

Signed-off-by: Andrii Nakryiko 
Signed-off-by: Alexei Starovoitov 
Link: https://lore.kernel.org/bpf/20191214014341.3442258-7-andriin@fb.com

tools, bpf: Rename pr_warning to pr_warn to align with kernel logging

2019-10-21T12:38:41+00:00

For kernel logging macros, pr_warning() is completely removed and
replaced by pr_warn(). By using pr_warn() in tools/lib/bpf/ for
symmetry to kernel logging macros, we could eventually drop the
use of pr_warning() in the whole kernel tree.

Signed-off-by: Kefeng Wang 
Signed-off-by: Daniel Borkmann 
Reviewed-by: Sergey Senozhatsky 
Acked-by: Andrii Nakryiko 
Link: https://lore.kernel.org/bpf/20191021055532.185245-1-wangkefeng.wang@huawei.com

libbpf: Handle invalid typedef emitted by old GCC

2019-10-11T21:11:55+00:00

Old GCC versions are producing invalid typedef for __gnuc_va_list
pointing to void. Special-case this and emit valid:

typedef __builtin_va_list __gnuc_va_list;

Reported-by: John Fastabend 
Signed-off-by: Andrii Nakryiko 
Signed-off-by: Daniel Borkmann 
Acked-by: Martin KaFai Lau 
Acked-by: John Fastabend 
Link: https://lore.kernel.org/bpf/20191011032901.452042-1-andriin@fb.com