Instead of determining buf_info string in the caller of check_buffer_access(),
we can determine whether the register type is read-only through
type_is_rdonly_mem() helper inside check_buffer_access() and construct
buf_info, making the code slightly cleaner.

Signed-off-by: Shung-Hsi Yu <shung-hsi.yu@suse.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/YiWYLnAkEZXBP/gH@syu-laptop

vmtest.sh also supports s390x now.

Signed-off-by: KP Singh <kpsingh@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220307133048.1287644-2-kpsingh@kernel.org

Dynamic linking when compiling on the host can cause issues when the
libc version does not match the one in the VM image. Update the
docs to explain how to do this.

Before:
  ./vmtest.sh -- ./test_progs -t test_ima
  ./test_progs: /usr/lib/libc.so.6: version `GLIBC_2.33' not found (required by ./test_progs)

After:

  LDLIBS=-static ./vmtest.sh -- ./test_progs -t test_ima
  test_ima:OK
  Summary: 1/0 PASSED, 0 SKIPPED, 0 FAILED

Reported-by: "Geyslan G. Bem" <geyslan@gmail.com>
Signed-off-by: KP Singh <kpsingh@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220307133048.1287644-1-kpsingh@kernel.org

The trailing slash of LIBBPF_SRCS is redundant, remove it. Also inline
it as its only used in LIBBPF_INCLUDE.

Signed-off-by: Yuntao Wang <ytcoode@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220305161013.361646-1-ytcoode@gmail.com

Fix the following coccicheck warning:
tools/lib/bpf/bpf.c:114:31-32: WARNING: Use ARRAY_SIZE
tools/lib/bpf/xsk.c:484:34-35: WARNING: Use ARRAY_SIZE
tools/lib/bpf/xsk.c:485:35-36: WARNING: Use ARRAY_SIZE

It has been tested with gcc (Debian 8.3.0-6) 8.3.0 on x86_64.

Signed-off-by: Guo Zhengkui <guozhengkui@vivo.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220306023426.19324-1-guozhengkui@vivo.com

Using strncpy() on NUL-terminated strings is considered deprecated[1].
Moreover, if the length of 'task->comm' is less than the destination buffer
size, strncpy() will NUL-pad the destination buffer, which is a needless
performance penalty.

Replacing strncpy() with strscpy() fixes all these issues.

[1] https://www.kernel.org/doc/html/latest/process/deprecated.html#strncpy-on-nul-terminated-strings



Signed-off-by: Yuntao Wang <ytcoode@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20220304070408.233658-1-ytcoode@gmail.com

xsk_umem__create() does mmap for fill/comp rings, but xsk_umem__delete()
doesn't do the unmap. This works fine for regular cases, because
xsk_socket__delete() does unmap for the rings. But for the case that
xsk_socket__create_shared() fails, umem rings are not unmapped.

fill_save/comp_save are checked to determine if rings have already be
unmapped by xsk. If fill_save and comp_save are NULL, it means that the
rings have already been used by xsk. Then they are supposed to be
unmapped by xsk_socket__delete(). Otherwise, xsk_umem__delete() does the
unmap.

Fixes: 2f6324a3

 ("libbpf: Support shared umems between queues and devices")
Signed-off-by: Cheng Li <lic121@chinatelecom.cn>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220301132623.GA19995@vscode.7~

Hao Luo says:

====================

This patchset is very much similar to Yonghong's patchset on adding
__user tagging [1], where a "user" btf_type_tag was introduced to
describe __user memory pointers. Similar approach can be applied on
__percpu pointers. The __percpu attribute in kernel is used to identify
pointers that point to memory allocated in percpu region. Normally,
accessing __percpu memory requires using special functions like
per_cpu_ptr() etc. Directly accessing __percpu pointer is meaningless.

Currently vmlinux BTF does not have a way to differentiate a __percpu
pointer from a regular pointer. So BPF programs are allowed to load
__percpu memory directly, which is an incorrect behavior.

With the previous work that encodes __user information in BTF, a nice
framework has been set up to allow us to encode __percpu information in
BTF and let the verifier to reject programs that try to directly access
percpu pointer. Previously, there is a PTR_TO_PERCPU_BTF_ID reg type which
is used to represent those percpu static variables in the kernel. Pahole
is able to collect variables that are stored in ".data..percpu" section
in the kernel image and emit BTF information for those variables. The
bpf_per_cpu_ptr() and bpf_this_cpu_ptr() helper functions were added to
access these variables. Now with __percpu information, we can tag those
__percpu fields in a struct (such as cgroup->rstat_cpu) and allow the
pair of bpf percpu helpers to access them as well.

In addition to adding __percpu tagging, this patchset also fixes a
harmless bug in the previous patch that introduced __user. Patch 01/04
is for that. Patch 02/04 adds the new attribute "percpu". Patch 03/04
adds MEM_PERCPU tag for PTR_TO_BTF_ID and replaces PTR_TO_PERCPU_BTF_ID
with (BTF_ID | MEM_PERCPU). Patch 04/04 refactors the btf_tag test a bit
and adds tests for percpu tag.

Like [1], the minimal requirements for btf_type_tag is
clang (>= clang14) and pahole (>= 1.23).

[1] https://lore.kernel.org/bpf/20211220015110.3rqxk5qwub3pa2gh@ast-mbp.dhcp.thefacebook.com/t/


====================

Signed-off-by: Alexei Starovoitov <ast@kernel.org>

Add test for percpu btf_type_tag. Similar to the "user" tag, we test
the following cases:

 1. __percpu struct field.
 2. __percpu as function parameter.
 3. per_cpu_ptr() accepts dynamically allocated __percpu memory.

Because the test for "user" and the test for "percpu" are very similar,
a little bit of refactoring has been done in btf_tag.c. Basically, both
tests share the same function for loading vmlinux and module btf.

Example output from log:

 > ./test_progs -v -t btf_tag

 libbpf: prog 'test_percpu1': BPF program load failed: Permission denied
 libbpf: prog 'test_percpu1': -- BEGIN PROG LOAD LOG --
 ...
 ; g = arg->a;
 1: (61) r1 = *(u32 *)(r1 +0)
 R1 is ptr_bpf_testmod_btf_type_tag_1 access percpu memory: off=0
 ...
 test_btf_type_tag_mod_percpu:PASS:btf_type_tag_percpu 0 nsec
 #26/6 btf_tag/btf_type_tag_percpu_mod1:OK

 libbpf: prog 'test_percpu2': BPF program load failed: Permission denied
 libbpf: prog 'test_percpu2': -- BEGIN PROG LOAD LOG --
 ...
 ; g = arg->p->a;
 2: (61) r1 = *(u32 *)(r1 +0)
 R1 is ptr_bpf_testmod_btf_type_tag_1 access percpu memory: off=0
 ...
 test_btf_type_tag_mod_percpu:PASS:btf_type_tag_percpu 0 nsec
 #26/7 btf_tag/btf_type_tag_percpu_mod2:OK

 libbpf: prog 'test_percpu_load': BPF program load failed: Permission denied
 libbpf: prog 'test_percpu_load': -- BEGIN PROG LOAD LOG --
 ...
 ; g = (__u64)cgrp->rstat_cpu->updated_children;
 2: (79) r1 = *(u64 *)(r1 +48)
 R1 is ptr_cgroup_rstat_cpu access percpu memory: off=48
 ...
 test_btf_type_tag_vmlinux_percpu:PASS:btf_type_tag_percpu_load 0 nsec
 #26/8 btf_tag/btf_type_tag_percpu_vmlinux_load:OK

 load_btfs:PASS:could not load vmlinux BTF 0 nsec
 test_btf_type_tag_vmlinux_percpu:PASS:btf_type_tag_percpu 0 nsec
 test_btf_type_tag_vmlinux_percpu:PASS:btf_type_tag_percpu_helper 0 nsec
 #26/9 btf_tag/btf_type_tag_percpu_vmlinux_helper:OK

Signed-off-by: Hao Luo <haoluo@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20220304191657.981240-5-haoluo@google.com

With the introduction of the btf_type_tag "percpu", we can add a
MEM_PERCPU to identify those pointers that point to percpu memory.
The ability of differetiating percpu pointers from regular memory
pointers have two benefits:

 1. It forbids unexpected use of percpu pointers, such as direct loads.
    In kernel, there are special functions used for accessing percpu
    memory. Directly loading percpu memory is meaningless. We already
    have BPF helpers like bpf_per_cpu_ptr() and bpf_this_cpu_ptr() that
    wrap the kernel percpu functions. So we can now convert percpu
    pointers into regular pointers in a safe way.

 2. Previously, bpf_per_cpu_ptr() and bpf_this_cpu_ptr() only work on
    PTR_TO_PERCPU_BTF_ID, a special reg_type which describes static
    percpu variables in kernel (we rely on pahole to encode them into
    vmlinux BTF). Now, since we can identify __percpu tagged pointers,
    we can also identify dynamically allocated percpu memory as well.
    It means we can use bpf_xxx_cpu_ptr() on dynamic percpu memory.
    This would be very convenient when accessing fields like
    "cgroup->rstat_cpu".

Signed-off-by: Hao Luo <haoluo@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20220304191657.981240-4-haoluo@google.com

This is similar to commit 7472d5a6 ("compiler_types: define __user as
__attribute__((btf_type_tag("user")))"), where a type tag "user" was
introduced to identify the pointers that point to user memory. With that
change, the newest compile toolchain can encode __user information into
vmlinux BTF, which can be used by the BPF verifier to enforce safe
program behaviors.

Similarly, we have __percpu attribute, which is mainly used to indicate
memory is allocated in percpu region. The __percpu pointers in kernel
are supposed to be used together with functions like per_cpu_ptr() and
this_cpu_ptr(), which perform necessary calculation on the pointer's
base address. Without the btf_type_tag introduced in this patch,
__percpu pointers will be treated as regular memory pointers in vmlinux
BTF and BPF programs are allowed to directly dereference them, generating
incorrect behaviors. Now with "percpu" btf_type_tag, the BPF verifier is
able to differentiate __percpu pointers from regular pointers and forbids
unexpected behaviors like direct load.

The following is an example similar to the one given in commit
7472d5a6:

  [$ ~] cat test.c
  #define __percpu __attribute__((btf_type_tag("percpu")))
  int foo(int __percpu *arg) {
  	return *arg;
  }
  [$ ~] clang -O2 -g -c test.c
  [$ ~] pahole -JV test.o
  ...
  File test.o:
  [1] INT int size=4 nr_bits=32 encoding=SIGNED
  [2] TYPE_TAG percpu type_id=1
  [3] PTR (anon) type_id=2
  [4] FUNC_PROTO (anon) return=1 args=(3 arg)
  [5] FUNC foo type_id=4
  [$ ~]

for the function argument "int __percpu *arg", its type is described as
	PTR -> TYPE_TAG(percpu) -> INT
The kernel can use this information for bpf verification or other
use cases.

Like commit 7472d5a6

, this feature requires clang (>= clang14) and
pahole (>= 1.23).

Signed-off-by: Hao Luo <haoluo@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20220304191657.981240-3-haoluo@google.com

With the introduction of MEM_USER in

 commit c6f1bfe8 ("bpf: reject program if a __user tagged memory accessed in kernel way")

PTR_TO_BTF_ID can be combined with a MEM_USER tag. Therefore, most
likely, when we compare reg_type against PTR_TO_BTF_ID, we want to use
the reg's base_type. Previously the check in check_mem_access() wants
to say: if the reg is BTF_ID but not NULL, the execution flow falls
into the 'then' branch. But now a reg of (BTF_ID | MEM_USER), which
should go into the 'then' branch, goes into the 'else'.

The end results before and after this patch are the same: regs tagged
with MEM_USER get rejected, but not in a way we intended. So fix the
condition, the error message now is correct.

Before (log from commit 696c3901):

  $ ./test_progs -v -n 22/3
  ...
  libbpf: prog 'test_user1': BPF program load failed: Permission denied
  libbpf: prog 'test_user1': -- BEGIN PROG LOAD LOG --
  R1 type=ctx expected=fp
  0: R1=ctx(id=0,off=0,imm=0) R10=fp0
  ; int BPF_PROG(test_user1, struct bpf_testmod_btf_type_tag_1 *arg)
  0: (79) r1 = *(u64 *)(r1 +0)
  func 'bpf_testmod_test_btf_type_tag_user_1' arg0 has btf_id 136561 type STRUCT 'bpf_testmod_btf_type_tag_1'
  1: R1_w=user_ptr_bpf_testmod_btf_type_tag_1(id=0,off=0,imm=0)
  ; g = arg->a;
  1: (61) r1 = *(u32 *)(r1 +0)
  R1 invalid mem access 'user_ptr_'

Now:

  libbpf: prog 'test_user1': BPF program load failed: Permission denied
  libbpf: prog 'test_user1': -- BEGIN PROG LOAD LOG --
  R1 type=ctx expected=fp
  0: R1=ctx(id=0,off=0,imm=0) R10=fp0
  ; int BPF_PROG(test_user1, struct bpf_testmod_btf_type_tag_1 *arg)
  0: (79) r1 = *(u64 *)(r1 +0)
  func 'bpf_testmod_test_btf_type_tag_user_1' arg0 has btf_id 104036 type STRUCT 'bpf_testmod_btf_type_tag_1'
  1: R1_w=user_ptr_bpf_testmod_btf_type_tag_1(id=0,ref_obj_id=0,off=0,imm=0)
  ; g = arg->a;
  1: (61) r1 = *(u32 *)(r1 +0)
  R1 is ptr_bpf_testmod_btf_type_tag_1 access user memory: off=0

Note the error message for the reason of rejection.

Fixes: c6f1bfe8

 ("bpf: reject program if a __user tagged memory accessed in kernel way")
Signed-off-by: Hao Luo <haoluo@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20220304191657.981240-2-haoluo@google.com

Kumar Kartikeya Dwivedi says:

====================

This set fixes a bug related to bad var_off being permitted for kfunc call in
case of PTR_TO_BTF_ID, consolidates offset checks for all register types allowed
as helper or kfunc arguments into a common shared helper, and introduces a
couple of other checks to harden the kfunc release logic and prevent future
bugs. Some selftests are also included that fail in absence of these fixes,
serving as demonstration of the issues being fixed.

Changelog:
----------
v3 -> v4:
v3: https://lore.kernel.org/bpf/20220304000508.2904128-1-memxor@gmail.com

 * Update commit message for __diag patch to say clang instead of LLVM (Nathan)
 * Address nits for check_func_arg_reg_off (Martin)
 * Add comment for fixed_off_ok case, remove is_kfunc check (Martin)

v2 -> v3:
v2: https://lore.kernel.org/bpf/20220303045029.2645297-1-memxor@gmail.com

 * Add my SoB to __diag for clang patch (Nathan)

v1 -> v2:
v1: https://lore.kernel.org/bpf/20220301065745.1634848-1-memxor@gmail.com

 * Put reg->off check for release kfunc inside check_func_arg_reg_off,
   make the check a bit more readable
 * Squash verifier selftests errstr update into patch 3 for bisect (Alexei)
 * Include fix from Nathan for clang warning about missing prototypes
 * Add unified __diag_ingore_all that works for both GCC/LLVM (Alexei)

Older discussion:
Link: https://lore.kernel.org/bpf/20220219113744.1852259-1-memxor@gmail.com



Kumar Kartikeya Dwivedi (7):
  bpf: Add check_func_arg_reg_off function
  bpf: Fix PTR_TO_BTF_ID var_off check
  bpf: Disallow negative offset in check_ptr_off_reg
  bpf: Harden register offset checks for release helpers and kfuncs
  compiler_types.h: Add unified __diag_ignore_all for GCC/LLVM
  bpf: Replace __diag_ignore with unified __diag_ignore_all
  selftests/bpf: Add tests for kfunc register offset checks
====================

Acked-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

Include a few verifier selftests that test against the problems being
fixed by previous commits, i.e. release kfunc always require
PTR_TO_BTF_ID fixed and var_off to be 0, and negative offset is not
permitted and returns a helpful error message.

Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20220304224645.3677453-9-memxor@gmail.com

Currently, -Wmissing-prototypes warning is ignored for GCC, but not
clang. This leads to clang build warning in W=1 mode. Since the flag
used by both compilers is same, we can use the unified __diag_ignore_all
macro that works for all supported versions and compilers which have
__diag macro support (currently GCC >= 8.0, and Clang >= 11.0).

Also add nf_conntrack_bpf.h include to prevent missing prototype warning
for register_nf_conntrack_bpf.

Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20220304224645.3677453-8-memxor@gmail.com

Add a __diag_ignore_all macro, to ignore warnings for both GCC and LLVM,
without having to specify the compiler type and version. By default, GCC
8 and clang 11 are used. This will be used by bpf subsystem to ignore
-Wmissing-prototypes warning for functions that are meant to be global
functions so that they are in vmlinux BTF, but don't have a prototype.

Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20220304224645.3677453-7-memxor@gmail.com

Add __diag macros similar to those in compiler-gcc.h, so that warnings
that need to be adjusted for specific cases but not globally can be
ignored when building with clang.

Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20220304224645.3677453-6-memxor@gmail.com

[ Kartikeya: wrote commit message ]

Let's ensure that the PTR_TO_BTF_ID reg being passed in to release BPF
helpers and kfuncs always has its offset set to 0. While not a real
problem now, there's a very real possibility this will become a problem
when more and more kfuncs are exposed, and more BPF helpers are added
which can release PTR_TO_BTF_ID.

Previous commits already protected against non-zero var_off. One of the
case we are concerned about now is when we have a type that can be
returned by e.g. an acquire kfunc:

struct foo {
	int a;
	int b;
	struct bar b;
};

... and struct bar is also a type that can be returned by another
acquire kfunc.

Then, doing the following sequence:

	struct foo *f = bpf_get_foo(); // acquire kfunc
	if (!f)
		return 0;
	bpf_put_bar(&f->b); // release kfunc

... would work with the current code, since the btf_struct_ids_match
takes reg->off into account for matching pointer type with release kfunc
argument type, but would obviously be incorrect, and most likely lead to
a kernel crash. A test has been included later to prevent regressions in
this area.

Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20220304224645.3677453-5-memxor@gmail.com

check_ptr_off_reg only allows fixed offset to be set for PTR_TO_BTF_ID,
where reg->off < 0 doesn't make sense. This would shift the pointer
backwards, and fails later in btf_struct_ids_match or btf_struct_walk
due to out of bounds access (since offset is interpreted as unsigned).

Improve the verifier by rejecting this case by using a better error
message for BPF helpers and kfunc, by putting a check inside the
check_func_arg_reg_off function.

Also, update existing verifier selftests to work with new error string.

Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20220304224645.3677453-4-memxor@gmail.com

When kfunc support was added, check_ctx_reg was called for PTR_TO_CTX
register, but no offset checks were made for PTR_TO_BTF_ID. Only
reg->off was taken into account by btf_struct_ids_match, which protected
against type mismatch due to non-zero reg->off, but when reg->off was
zero, a user could set the variable offset of the register and allow it
to be passed to kfunc, leading to bad pointer being passed into the
kernel.

Fix this by reusing the extracted helper check_func_arg_reg_off from
previous commit, and make one call before checking all supported
register types. Since the list is maintained, any future changes will be
taken into account by updating check_func_arg_reg_off. This function
prevents non-zero var_off to be set for PTR_TO_BTF_ID, but still allows
a fixed non-zero reg->off, which is needed for type matching to work
correctly when using pointer arithmetic.

ARG_DONTCARE is passed as arg_type, since kfunc doesn't support
accepting a ARG_PTR_TO_ALLOC_MEM without relying on size of parameter
type from BTF (in case of pointer), or using a mem, len pair. The
forcing of offset check for ARG_PTR_TO_ALLOC_MEM is done because ringbuf
helpers obtain the size from the header located at the beginning of the
memory region, hence any changes to the original pointer shouldn't be
allowed. In case of kfunc, size is always known, either at verification
time, or using the length parameter, hence this forcing is not required.

Since this check will happen once already for PTR_TO_CTX, remove the
check_ptr_off_reg call inside its block.

Fixes: e6ac2450

 ("bpf: Support bpf program calling kernel function")
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20220304224645.3677453-3-memxor@gmail.com

Lift the list of register types allowed for having fixed and variable
offsets when passed as helper function arguments into a common helper,
so that they can be reused for kfunc checks in later commits. Keeping a
common helper aids maintainability and allows us to follow the same
consistent rules across helpers and kfuncs. Also, convert check_func_arg
to use this function.

Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20220304224645.3677453-2-memxor@gmail.com

Andrii Nakryiko says:

====================

Add ability for user applications and libraries to register custom BPF program
SEC() handlers. See patch #2 for examples where this is useful.

Patch #1 does some preliminary refactoring to allow exponsing program
init, preload, and attach callbacks as public API. It also establishes
a protocol to allow optional auto-attach behavior. This will also help the
case of sometimes auto-attachable uprobes.

v4->v5:
  - API documentation improvements (Daniel);
v3->v4:
  - init_fn -> prog_setup_fn, preload_fn -> prog_prepare_load_fn (Alexei);
v2->v3:
  - moved callbacks and cookie into OPTS struct (Alan);
  - added more test scenarios (Alan);
  - address most of Alan's feedback, but kept API name;
v1->v2:
  - resubmitting due to git send-email screw up.

Cc: Alan Maguire <alan.maguire@oracle.com>
====================

Signed-off-by: Alexei Starovoitov <ast@kernel.org>

Add a selftest validating various aspects of libbpf's handling of custom
SEC() handlers. It also demonstrates how libraries can ensure very early
callbacks registration and unregistration using
__attribute__((constructor))/__attribute__((destructor)) functions.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Tested-by: Alan Maguire <alan.maguire@oracle.com>
Reviewed-by: Alan Maguire <alan.maguire@oracle.com>
Link: https://lore.kernel.org/bpf/20220305010129.1549719-4-andrii@kernel.org

Allow registering and unregistering custom handlers for BPF program.
This allows user applications and libraries to plug into libbpf's
declarative SEC() definition handling logic. This allows to offload
complex and intricate custom logic into external libraries, but still
provide a great user experience.

One such example is USDT handling library, which has a lot of code and
complexity which doesn't make sense to put into libbpf directly, but it
would be really great for users to be able to specify BPF programs with
something like SEC("usdt/<path-to-binary>:<usdt_provider>:<usdt_name>")
and have correct BPF program type set (BPF_PROGRAM_TYPE_KPROBE, as it is
uprobe) and even support BPF skeleton's auto-attach logic.

In some cases, it might be even good idea to override libbpf's default
handling, like for SEC("perf_event") programs. With custom library, it's
possible to extend logic to support specifying perf event specification
right there in SEC() definition without burdening libbpf with lots of
custom logic or extra library dependecies (e.g., libpfm4). With current
patch it's possible to override libbpf's SEC("perf_event") handling and
specify a completely custom ones.

Further, it's possible to specify a generic fallback handling for any
SEC() that doesn't match any other custom or standard libbpf handlers.
This allows to accommodate whatever legacy use cases there might be, if
necessary.

See doc comments for libbpf_register_prog_handler() and
libbpf_unregister_prog_handler() for detailed semantics.

This patch also bumps libbpf development version to v0.8 and adds new
APIs there.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Tested-by: Alan Maguire <alan.maguire@oracle.com>
Reviewed-by: Alan Maguire <alan.maguire@oracle.com>
Link: https://lore.kernel.org/bpf/20220305010129.1549719-3-andrii@kernel.org

Allow some BPF program types to support auto-attach only in subste of
cases. Currently, if some BPF program type specifies attach callback, it
is assumed that during skeleton attach operation all such programs
either successfully attach or entire skeleton attachment fails. If some
program doesn't support auto-attachment from skeleton, such BPF program
types shouldn't have attach callback specified.

This is limiting for cases when, depending on how full the SEC("")
definition is, there could either be enough details to support
auto-attach or there might not be and user has to use some specific API
to provide more details at runtime.

One specific example of such desired behavior might be SEC("uprobe"). If
it's specified as just uprobe auto-attach isn't possible. But if it's
SEC("uprobe/<some_binary>:<some_func>") then there are enough details to
support auto-attach. Note that there is a somewhat subtle difference
between auto-attach behavior of BPF skeleton and using "generic"
bpf_program__attach(prog) (which uses the same attach handlers under the
cover). Skeleton allow some programs within bpf_object to not have
auto-attach implemented and doesn't treat that as an error. Instead such
BPF programs are just skipped during skeleton's (optional) attach step.
bpf_program__attach(), on the other hand, is called when user *expects*
auto-attach to work, so if specified program doesn't implement or
doesn't support auto-attach functionality, that will be treated as an
error.

Another improvement to the way libbpf is handling SEC()s would be to not
require providing dummy kernel function name for kprobe. Currently,
SEC("kprobe/whatever") is necessary even if actual kernel function is
determined by user at runtime and bpf_program__attach_kprobe() is used
to specify it. With changes in this patch, it's possible to support both
SEC("kprobe") and SEC("kprobe/<actual_kernel_function"), while only in
the latter case auto-attach will be performed. In the former one, such
kprobe will be skipped during skeleton attach operation.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Tested-by: Alan Maguire <alan.maguire@oracle.com>
Reviewed-by: Alan Maguire <alan.maguire@oracle.com>
Link: https://lore.kernel.org/bpf/20220305010129.1549719-2-andrii@kernel.org

Michael Chan says:

====================
bnxt_en: Updates.

This patch series contains mainly NVRAM related features.  More
NVRAM error checking and logging are added when installing firmware
packages.  A new devlink hw health report is now added to report
and diagnose NVRAM issues.  Other miscellaneous patches include
reporting correctly cards that don't support link pause, adding
an internal unknown link state, and avoiding unnecessary link
toggle during firmware reset.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

Add an NVM test function for devlink hw reporter.
In this function an NVM VPD area is read followed by
a write. Test result is cached and if it is successful then
the next test can be conducted only after HW_RETEST_MIN_TIME to
avoid frequent writes to the NVM.

Reviewed-by: Edwin Peer <edwin.peer@broadcom.com>
Signed-off-by: Vikas Gupta <vikas.gupta@broadcom.com>
Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

This reporter will report NVM errors which are non-fatal.
When we receive these NVM error events, we'll report it
through this new hw health reporter.

Reviewed-by: Edwin Peer <edwin.peer@broadcom.com>
Signed-off-by: Kalesh AP <kalesh-anakkur.purayil@broadcom.com>
Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Health reporter state should be maintained over resets. Previously
reporters were destroyed if the device capabilities changed, but
since none of the reporters depend on capabilities anymore, this
logic should be removed.

Signed-off-by: Edwin Peer <edwin.peer@broadcom.com>
Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

If the flow control settings have been changed, a subsequent FW reset
may cause the ethernet link to toggle unnecessarily.  This link toggle
will increase the down time by a few seconds.

The problem is caused by bnxt_update_phy_setting() detecting a false
mismatch in the flow control settings between the stored software
settings and the current FW settings after the FW reset.  This mismatch
is caused by the AUTONEG bit added to link_info->req_flow_ctrl in an
inconsistent way in bnxt_set_pauseparam() in autoneg mode.  The AUTONEG
bit should not be added to link_info->req_flow_ctrl.

Reviewed-by: Colin Winegarden <colin.winegarden@broadcom.com>
Reviewed-by: Pavan Chebbi <pavan.chebbi@broadcom.com>
Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Some cards are configured to never support link pause or PFC.  Discover
these cards and properly report no pause support to ethtool.  Disable
PFC settings from DCBNL if PFC is unsupported.

Reviewed-by: Pavan Chebbi <pavan.chebbi@broadcom.com>
Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

This will force link state to always be logged for initial NIC open.

Signed-off-by: Edwin Peer <edwin.peer@broadcom.com>
Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Instead of always returning -ENOPKG, decode the firmware error
code further when the HWRM_NVM_INSTALL_UPDATE firmware call fails.
Return a more suitable error code to userspace and log an error
in dmesg.

Reviewed-by: Somnath Kotur <somnath.kotur@broadcom.com>
Reviewed-by: Pavan Chebbi <pavan.chebbi@broadcom.com>
Signed-off-by: Kalesh AP <kalesh-anakkur.purayil@broadcom.com>
Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

FW returns error code "NVM_INSTALL_UPDATE_CMD_ERR_CODE_ANTI_ROLLBACK"
in the response to indicate that HWRM_NVM_INSTALL_UPDATE command has
failed due to Anti-rollback feature. Parse the error and return an
appropriate error code to the user.

Reviewed-by: Somnath Kotur <somnath.kotur@broadcom.com>
Reviewed-by: Edwin Peer <edwin.peer@broadcom.com>
Signed-off-by: Kalesh AP <kalesh-anakkur.purayil@broadcom.com>
Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

This is in anticipation of handling more "cmd_err" from FW in the next
patch.

Reviewed-by: Somnath Kotur <somnath.kotur@broadcom.com>
Reviewed-by: Edwin Peer <edwin.peer@broadcom.com>
Signed-off-by: Kalesh AP <kalesh-anakkur.purayil@broadcom.com>
Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Robert Hancock says:

====================
NAPI/GRO support for axienet driver

Add support for NAPI and GRO receive in the Xilinx AXI Ethernet driver,
and some other related cleanups.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

Add the ability to configure the RX/TX coalesce timer with ethtool.
Change default setting to scale with the clock rate rather than being a
fixed number of clock cycles.

Signed-off-by: Robert Hancock <robert.hancock@calian.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Now that NAPI has been implemented, the hardware interrupt mitigation
mechanism is not needed to avoid excessive interrupt load in most cases.
Reduce the default RX interrupt threshold to 1 to reduce introduced
latency. This can be increased with ethtool if desired if some applications
still want to reduce interrupts.

Signed-off-by: Robert Hancock <robert.hancock@calian.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Implement NAPI and GRO receive. In addition to better performance, this
also avoids handling RX packets in hard IRQ context, which reduces the
IRQ latency impact to other devices.

Signed-off-by: Robert Hancock <robert.hancock@calian.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

When the RX or TX coalesce count is set to 1, there's no point in
setting the delay timer value since an interrupt will already be raised
on every packet, and the delay interrupt just causes extra pointless
interrupts.

Signed-off-by: Robert Hancock <robert.hancock@calian.com>
Signed-off-by: David S. Miller <davem@davemloft.net>