- 28 Sep, 2021 19 commits
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Andrii Nakryiko authored
Normalize all the other non-conforming SEC() usages across all selftests. This is in preparation for libbpf to start to enforce stricter SEC() rules in libbpf 1.0 mode. Signed-off-by:
Andrii Nakryiko <andrii@kernel.org> Signed-off-by:
Alexei Starovoitov <ast@kernel.org> Acked-by:
Dave Marchevsky <davemarchevsky@fb.com> Link: https://lore.kernel.org/bpf/20210928161946.2512801-5-andrii@kernel.org
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Andrii Nakryiko authored
Convert all SEC("classifier*") uses to a new and strict SEC("tc") section name. In reference_tracking selftests switch from ambiguous searching by program title (section name) to non-ambiguous searching by name in some selftests, getting closer to completely removing bpf_object__find_program_by_title(). Signed-off-by: -
Andrii Nakryiko authored
Convert almost all SEC("xdp_blah") uses to strict SEC("xdp") to comply with strict libbpf 1.0 logic of exact section name match for XDP program types. There is only one exception, which is only tested through iproute2 and defines multiple XDP programs within the same BPF object. Given iproute2 still works in non-strict libbpf mode and it doesn't have means to specify XDP programs by its name (not section name/title), leave that single file alone for now until iproute2 gains lookup by function/program name. Signed-off-by: -
Andrii Nakryiko authored
As argued in [0], add "tc" ELF section definition for SCHED_CLS BPF program type. "classifier" is a misleading terminology and should be migrated away from. [0] https://lore.kernel.org/bpf/270e27b1-e5be-5b1c-b343-51bd644d0747@iogearbox.net/Signed-off-by:
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Johan Almbladh authored
This patch adds a tail call limit test where the program also emits a BPF_CALL to an external function prior to the tail call. Mainly testing that JITed programs preserve its internal register state, for example tail call count, across such external calls. Signed-off-by:
Johan Almbladh <johan.almbladh@anyfinetworks.com> Signed-off-by:
Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20210914091842.4186267-15-johan.almbladh@anyfinetworks.com
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Johan Almbladh authored
This patch fixes an error in the tail call limit test that caused the test to fail on for x86-64 JIT. Previously, the register R0 was used to report the total number of tail calls made. However, after a tail call fall-through, the value of the R0 register is undefined. Now, all tail call error path tests instead use context state to store the count. Fixes: 874be05f ("bpf, tests: Add tail call test suite") Reported-by:
Paul Chaignon <paul@cilium.io> Reported-by:
Tiezhu Yang <yangtiezhu@loongson.cn> Signed-off-by:
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Johan Almbladh authored
This patch adds tests of the high 32 bits of 64-bit BPF_END conversions. It also adds a mirrored set of tests where the source bytes are reversed. The MSB of each byte is now set on the high word instead, possibly affecting sign-extension during conversion in a different way. Mainly for JIT testing. Signed-off-by:
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Johan Almbladh authored
This patch expands the branch conversion test introduced by 66e5eb84 ("bpf, tests: Add branch conversion JIT test"). The test now includes a JMP with maximum eBPF offset. This triggers branch conversion for the 64-bit MIPS JIT. Additional variants are also added for cases when the branch is taken or not taken. Signed-off-by:
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Johan Almbladh authored
This patch adds a set of tests for JMP and JMP32 operations where the branch decision is know at JIT time. Mainly testing JIT behaviour. Signed-off-by:
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Johan Almbladh authored
This patch adds a set of tests for JMP to verify that the JITed jump offset is calculated correctly. We pretend that the verifier has inserted any zero extensions to make the jump-over operations JIT to one instruction each, in order to control the exact JITed jump offset. Signed-off-by:
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Johan Almbladh authored
This patch adds a new flag to indicate that the verified did insert zero-extensions, even though the verifier is not being run for any of the tests. Signed-off-by:
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Johan Almbladh authored
This patch adds a test for the 64-bit immediate load, a two-instruction operation, to verify correctness for all possible magnitudes of the immediate operand. Mainly intended for JIT testing. Signed-off-by:
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Johan Almbladh authored
This patch adds a new type of jump test where the program jumps forwards and backwards with increasing offset. It mainly tests JITs where a relative jump may generate different JITed code depending on the offset size, read MIPS. Signed-off-by:
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Johan Almbladh authored
This patch adds a set of tests for conditional JMP and JMP32 operations to verify correctness for all possible magnitudes of the immediate and register operands. Mainly intended for JIT testing. Signed-off-by:
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Johan Almbladh authored
This patch adds a set of tests for ALU64 and ALU32 arithmetic and bitwise logical operations to verify correctness for all possible magnitudes of the register and immediate operands. Mainly intended for JIT testing. The patch introduces a pattern generator that can be used to drive extensive tests of different kinds of operations. It is parameterized to allow tuning of the operand combinations to test. Signed-off-by:
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Johan Almbladh authored
This patch adds a set of tests for ALU64 and ALU32 shift operations to verify correctness for all possible values of the shift value. Mainly intended for JIT testing. Signed-off-by:
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Johan Almbladh authored
The test suite used to call any fill_helper callbacks to generate eBPF program data for all test cases at once. This caused ballooning memory requirements as more extensive test cases were added. Now the each fill_helper is called before the test is run and the allocated memory released afterwards, before the next test case is processed. Signed-off-by:
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Johan Almbladh authored
This patch allows a test cast to specify the number of runs to use. For compatibility with existing test case definitions, the default value 0 is interpreted as MAX_TESTRUNS. A reduced number of runs is useful for complex test programs where 1000 runs may take a very long time. Instead of reducing what is tested, one can instead reduce the number of times the test is run. Signed-off-by:
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Toke Høiland-Jørgensen authored
When parsing legacy map definitions, libbpf would error out when encountering an STT_SECTION symbol. This becomes a problem because some versions of binutils will produce SECTION symbols for every section when processing an ELF file, so BPF files run through 'strip' will end up with such symbols, making libbpf refuse to load them. There's not really any reason why erroring out is strictly necessary, so change libbpf to just ignore SECTION symbols when parsing the ELF. Signed-off-by:
Toke Høiland-Jørgensen <toke@redhat.com> Signed-off-by:
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- 27 Sep, 2021 14 commits
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Daniel Borkmann authored
Magnus Karlsson says: ==================== This patch set introduces a batched interface for Rx buffer allocation in AF_XDP buffer pool. Instead of using xsk_buff_alloc(*pool), drivers can now use xsk_buff_alloc_batch(*pool, **xdp_buff_array, max). Instead of returning a pointer to an xdp_buff, it returns the number of xdp_buffs it managed to allocate up to the maximum value of the max parameter in the function call. Pointers to the allocated xdp_buff:s are put in the xdp_buff_array supplied in the call. This could be a SW ring that already exists in the driver or a new structure that the driver has allocated. u32 xsk_buff_alloc_batch(struct xsk_buff_pool *pool, struct xdp_buff **xdp, u32 max); When using this interface, the driver should also use the new interface below to set the relevant fields in the struct xdp_buff. The reason for this is that xsk_buff_alloc_batch() does not fill in the data and data_meta fields for you as is the case with xsk_buff_alloc(). So it is not sufficient to just set data_end (effectively the size) anymore in the driver. The reason for this is performance as explained in detail in the commit message. void xsk_buff_set_size(struct xdp_buff *xdp, u32 size); Patch 6 also optimizes the buffer allocation in the aligned case. In this case, we can skip the reinitialization of most fields in the xdp_buff_xsk struct at allocation time. As the number of elements in the heads array is equal to the number of possible buffers in the umem, we can initialize them once and for all at bind time and then just point to the correct one in the xdp_buff_array that is returned to the driver. No reason to have a stack of free head entries. In the unaligned case, the buffers can reside anywhere in the umem, so this optimization is not possible as we still have to fill in the right information in the xdp_buff every single time one is allocated. I have updated i40e and ice to use this new batched interface. These are the throughput results on my 2.1 GHz Cascade Lake system: Aligned mode: ice: +11% / -9 cycles/pkt i40e: +12% / -9 cycles/pkt Unaligned mode: ice: +1.5% / -1 cycle/pkt i40e: +1% / -1 cycle/pkt For the aligned case, batching provides around 40% of the performance improvement and the aligned optimization the rest, around 60%. Would have expected a ~4% boost for unaligned with this data, but I only get around 1%. Do not know why. Note that memory consumption in aligned mode is also reduced by this patch set. ==================== Signed-off-by: -
Magnus Karlsson authored
Add a test for the frame_headroom feature that can be set on the umem. The logic added validates that all offsets in all tests and packets are valid, not just the ones that have a specifically configured frame_headroom. Signed-off-by:
Magnus Karlsson <magnus.karlsson@intel.com> Signed-off-by:
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Magnus Karlsson authored
Change the interleaving of packets in unaligned mode. With the current buffer addresses in the packet stream, the last buffer in the umem could not be used as a large packet could potentially write over the end of the umem. The kernel correctly threw this buffer address away and refused to use it. This is perfectly fine for all regular packet streams, but the ones used for unaligned mode have every other packet being at some different offset. As we will add checks for correct offsets in the next patch, this needs to be fixed. Just start these page-boundary straddling buffers one page earlier so that the last one is not on the last page of the umem, making all buffers valid. Signed-off-by:
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Magnus Karlsson authored
Add a test where a single packet is sent and received. This might sound like a silly test, but since many of the interfaces in xsk are batched, it is important to be able to validate that we did not break something as fundamental as just receiving single packets, instead of batches of packets at high speed. Signed-off-by:
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Magnus Karlsson authored
Introduce pacing of traffic so that the Tx thread can never send more packets than the receiver has processed plus the number of packets it can have in its umem. So at any point in time, the number of in flight packets (not processed by the Rx thread) are less than or equal to the number of packets that can be held in the Rx thread's umem. The batch size is also increased to improve running time. Signed-off-by:
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Magnus Karlsson authored
The socket creation retry unnecessarily registered the umem once for every retry. No reason to do this. It wastes memory and it might lead to too many pages being locked at some point and the failure of a test. Signed-off-by:
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Magnus Karlsson authored
Fix a problem where the fill ring was populated with too many entries. If number of buffers in the umem was smaller than the fill ring size, the code used to loop over from the beginning of the umem and start putting the same buffers in again. This is racy indeed as a later packet can be received overwriting an earlier one before the Rx thread manages to validate it. Signed-off-by:
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Magnus Karlsson authored
Fix missing initialization of the member rx_pkt_nb in the packet stream. This leads to some tests declaring success too early as the test thought all packets had already been received. Signed-off-by:
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Magnus Karlsson authored
Optimize for the aligned case by precomputing the parameter values of the xdp_buff_xsk and xdp_buff structures in the heads array. We can do this as the heads array size is equal to the number of chunks in the umem for the aligned case. Then every entry in this array will reflect a certain chunk/frame and can therefore be prepopulated with the correct values and we can drop the use of the free_heads stack. Note that it is not possible to allocate more buffers than what has been allocated in the aligned case since each chunk can only contain a single buffer. We can unfortunately not do this in the unaligned case as one chunk might contain multiple buffers. In this case, we keep the old scheme of populating a heads entry every time it is used and using the free_heads stack. Also move xp_release() and xp_get_handle() to xsk_buff_pool.h. They were for some reason in xsk.c even though they are buffer pool operations. Signed-off-by:
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Magnus Karlsson authored
Use the new xsk batched rx allocation interface for the zero-copy data path. As the array of struct xdp_buff pointers kept by the driver is really a ring that wraps, the allocation routine is modified to detect a wrap and in that case call the allocation function twice. The allocation function cannot deal with wrapped rings, only arrays. As we now know exactly how many buffers we get and that there is no wrapping, the allocation function can be simplified even more as all if-statements in the allocation loop can be removed, improving performance. Signed-off-by:
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Magnus Karlsson authored
Use the new xsk batched rx allocation interface for the zero-copy data path. As the array of struct xdp_buff pointers kept by the driver is really a ring that wraps, the allocation routine is modified to detect a wrap and in that case call the allocation function twice. The allocation function cannot deal with wrapped rings, only arrays. As we now know exactly how many buffers we get and that there is no wrapping, the allocation function can be simplified even more as all if-statements in the allocation loop can be removed, improving performance. Signed-off-by:
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Magnus Karlsson authored
In order to use the new xsk batched buffer allocation interface, a pointer to an array of struct xsk_buff pointers need to be provided so that the function can put the result of the allocation there. In the ice driver, we already have a ring that stores pointers to xdp_buffs. This is only used for the xsk zero-copy driver and is a union with the structure that is used for the regular non zero-copy path. Unfortunately, that structure is larger than the xdp_buffs pointers which mean that there will be a stride (of 20 bytes) between each xdp_buff pointer. And feeding this into the xsk_buff_alloc_batch interface will not work since it assumes a regular array of xdp_buff pointers (each 8 bytes with 0 bytes in-between them on a 64-bit system). To fix this, remove the xdp_buff pointer from the rx_buf union and move it one step higher to the union above which only has pointers to arrays in it. This solves the problem and we can directly feed the SW ring of xdp_buff pointers straight into the allocation function in the next patch when that interface is used. This will improve performance. Signed-off-by:
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Magnus Karlsson authored
Add a new driver interface xsk_buff_alloc_batch() offering batched buffer allocations to improve performance. The new interface takes three arguments: the buffer pool to allocated from, a pointer to an array of struct xdp_buff pointers which will contain pointers to the allocated xdp_buffs, and an unsigned integer specifying the max number of buffers to allocate. The return value is the actual number of buffers that the allocator managed to allocate and it will be in the range 0 <= N <= max, where max is the third parameter to the function. u32 xsk_buff_alloc_batch(struct xsk_buff_pool *pool, struct xdp_buff **xdp, u32 max); A second driver interface is also introduced that need to be used in conjunction with xsk_buff_alloc_batch(). It is a helper that sets the size of struct xdp_buff and is used by the NIC Rx irq routine when receiving a packet. This helper sets the three struct members data, data_meta, and data_end. The two first ones is in the xsk_buff_alloc() case set in the allocation routine and data_end is set when a packet is received in the receive irq function. This unfortunately leads to worse performance since the xdp_buff is touched twice with a long time period in between leading to an extra cache miss. Instead, we fill out the xdp_buff with all 3 fields at one single point in time in the driver, when the size of the packet is known. Hence this helper. Note that the driver has to use this helper (or set all three fields itself) when using xsk_buff_alloc_batch(). xsk_buff_alloc() works as before and does not require this. void xsk_buff_set_size(struct xdp_buff *xdp, u32 size); Signed-off-by: -
Magnus Karlsson authored
Get rid of the unused entry "unaligned" in struct xdp_buff_xsk. Signed-off-by:
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- 26 Sep, 2021 5 commits
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Alexei Starovoitov authored
Martin KaFai says: ==================== The verifier currently does not save the reg state when spilling <8byte bounded scalar to the stack. The bpf program will be incorrectly rejected when this scalar is refilled to the reg and then used to offset into a packet header. The later patch has a simplified bpf prog from a real use case to demonstrate this case. The current work around is to reparse the packet again such that this offset scalar is close to where the packet data will be accessed to avoid the spill. Thus, the header is parsed twice. The llvm patch [1] will align the <8bytes spill to the 8-byte stack address. This set is to make the necessary changes in verifier to support <8byte scalar spill and refill. [1] https://reviews.llvm.org/D109073 v2: - Changed the xdpwall selftest in patch 3 to trigger a u32 spill at a non 8-byte aligned stack address. The v1 has simplified the real example too much such that it only triggers a u32 spill but does not spill at a non 8-byte aligned stack address. - Changed README.rst in patch 3 to explain the llvm dependency for the xdpwall test. ==================== Signed-off-by:
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Martin KaFai Lau authored
This patch adds a few verifier tests for <8-byte spill and refill. Signed-off-by:
Martin KaFai Lau <kafai@fb.com> Signed-off-by:
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Martin KaFai Lau authored
It is a simplified example that can trigger a 32bit scalar spill. The const scalar is refilled and added to a skb->data later. Since the reg state of the 32bit scalar spill is not saved now, adding the refilled reg to skb->data and then comparing it with skb->data_end cannot verify the skb->data access. With the earlier verifier patch and the llvm patch [1]. The verifier can correctly verify the bpf prog. Here is the snippet of the verifier log that leads to verifier conclusion that the packet data is unsafe to read. The log is from the kerne without the previous verifier patch to save the <8-byte scalar spill. 67: R0=inv1 R1=inv17 R2=invP2 R3=inv1 R4=pkt(id=0,off=68,r=102,imm=0) R5=inv102 R6=pkt(id=0,off=62,r=102,imm=0) R7=pkt(id=0,off=0,r=102,imm=0) R8=pkt_end(id=0,off=0,imm=0) R9=inv17 R10=fp0 67: (63) *(u32 *)(r10 -12) = r5 68: R0=inv1 R1=inv17 R2=invP2 R3=inv1 R4=pkt(id=0,off=68,r=102,imm=0) R5=inv102 R6=pkt(id=0,off=62,r=102,imm=0) R7=pkt(id=0,off=0,r=102,imm=0) R8=pkt_end(id=0,off=0,imm=0) R9=inv17 R10=fp0 fp-16=mmmm???? ... 101: R0_w=map_value_or_null(id=2,off=0,ks=16,vs=1,imm=0) R6_w=pkt(id=0,off=70,r=102,imm=0) R7=pkt(id=0,off=0,r=102,imm=0) R8=pkt_end(id=0,off=0,imm=0) R9=inv17 R10=fp0 fp-16=mmmmmmmm 101: (61) r1 = *(u32 *)(r10 -12) 102: R0_w=map_value_or_null(id=2,off=0,ks=16,vs=1,imm=0) R1_w=inv(id=0,umax_value=4294967295,var_off=(0x0; 0xffffffff)) R6_w=pkt(id=0,off=70,r=102,imm=0) R7=pkt(id=0,off=0,r=102,imm=0) R8=pkt_end(id=0,off=0,imm=0) R9=inv17 R10=fp0 fp-16=mmmmmmmm 102: (bc) w1 = w1 103: R0_w=map_value_or_null(id=2,off=0,ks=16,vs=1,imm=0) R1_w=inv(id=0,umax_value=4294967295,var_off=(0x0; 0xffffffff)) R6_w=pkt(id=0,off=70,r=102,imm=0) R7=pkt(id=0,off=0,r=102,imm=0) R8=pkt_end(id=0,off=0,imm=0) R9=inv17 R10=fp0 fp-16=mmmmmmmm 103: (0f) r7 += r1 last_idx 103 first_idx 67 regs=2 stack=0 before 102: (bc) w1 = w1 regs=2 stack=0 before 101: (61) r1 = *(u32 *)(r10 -12) 104: R0_w=map_value_or_null(id=2,off=0,ks=16,vs=1,imm=0) R1_w=invP(id=0,umax_value=4294967295,var_off=(0x0; 0xffffffff)) R6_w=pkt(id=0,off=70,r=102,imm=0) R7_w=pkt(id=3,off=0,r=0,umax_value=4294967295,var_off=(0x0; 0xffffffff)) R8=pkt_end(id=0,off=0,imm=0) R9=inv17 R10=fp0 fp-16=mmmmmmmm ... 127: R0_w=inv1 R1=invP(id=0,umax_value=4294967295,var_off=(0x0; 0xffffffff)) R6=pkt(id=0,off=70,r=102,imm=0) R7=pkt(id=3,off=0,r=0,umax_value=4294967295,var_off=(0x0; 0xffffffff)) R8=pkt_end(id=0,off=0,imm=0) R9_w=invP17 R10=fp0 fp-16=mmmmmmmm 127: (bf) r1 = r7 128: R0_w=inv1 R1_w=pkt(id=3,off=0,r=0,umax_value=4294967295,var_off=(0x0; 0xffffffff)) R6=pkt(id=0,off=70,r=102,imm=0) R7=pkt(id=3,off=0,r=0,umax_value=4294967295,var_off=(0x0; 0xffffffff)) R8=pkt_end(id=0,off=0,imm=0) R9_w=invP17 R10=fp0 fp-16=mmmmmmmm 128: (07) r1 += 8 129: R0_w=inv1 R1_w=pkt(id=3,off=8,r=0,umax_value=4294967295,var_off=(0x0; 0xffffffff)) R6=pkt(id=0,off=70,r=102,imm=0) R7=pkt(id=3,off=0,r=0,umax_value=4294967295,var_off=(0x0; 0xffffffff)) R8=pkt_end(id=0,off=0,imm=0) R9_w=invP17 R10=fp0 fp-16=mmmmmmmm 129: (b4) w0 = 1 130: R0=inv1 R1=pkt(id=3,off=8,r=0,umax_value=4294967295,var_off=(0x0; 0xffffffff)) R6=pkt(id=0,off=70,r=102,imm=0) R7=pkt(id=3,off=0,r=0,umax_value=4294967295,var_off=(0x0; 0xffffffff)) R8=pkt_end(id=0,off=0,imm=0) R9=invP17 R10=fp0 fp-16=mmmmmmmm 130: (2d) if r1 > r8 goto pc-66 R0=inv1 R1=pkt(id=3,off=8,r=0,umax_value=4294967295,var_off=(0x0; 0xffffffff)) R6=pkt(id=0,off=70,r=102,imm=0) R7=pkt(id=3,off=0,r=0,umax_value=4294967295,var_off=(0x0; 0xffffffff)) R8=pkt_end(id=0,off=0,imm=0) R9=invP17 R10=fp0 fp-16=mmmmmmmm 131: R0=inv1 R1=pkt(id=3,off=8,r=0,umax_value=4294967295,var_off=(0x0; 0xffffffff)) R6=pkt(id=0,off=70,r=102,imm=0) R7=pkt(id=3,off=0,r=0,umax_value=4294967295,var_off=(0x0; 0xffffffff)) R8=pkt_end(id=0,off=0,imm=0) R9=invP17 R10=fp0 fp-16=mmmmmmmm 131: (69) r6 = *(u16 *)(r7 +0) invalid access to packet, off=0 size=2, R7(id=3,off=0,r=0) R7 offset is outside of the packet [1]: https://reviews.llvm.org/D109073Signed-off-by:
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Martin KaFai Lau authored
The verifier currently does not save the reg state when spilling <8byte bounded scalar to the stack. The bpf program will be incorrectly rejected when this scalar is refilled to the reg and then used to offset into a packet header. The later patch has a simplified bpf prog from a real use case to demonstrate this case. The current work around is to reparse the packet again such that this offset scalar is close to where the packet data will be accessed to avoid the spill. Thus, the header is parsed twice. The llvm patch [1] will align the <8bytes spill to the 8-byte stack address. This can simplify the verifier support by avoiding to store multiple reg states for each 8 byte stack slot. This patch changes the verifier to save the reg state when spilling <8bytes scalar to the stack. This reg state saving is limited to spill aligned to the 8-byte stack address. The current refill logic has already called coerce_reg_to_size(), so coerce_reg_to_size() is not called on state->stack[spi].spilled_ptr during spill. When refilling in check_stack_read_fixed_off(), it checks the refill size is the same as the number of bytes marked with STACK_SPILL before restoring the reg state. When restoring the reg state to state->regs[dst_regno], it needs to avoid the state->regs[dst_regno].subreg_def being over written because it has been marked by the check_reg_arg() earlier [check_mem_access() is called after check_reg_arg() in do_check()]. Reordering check_mem_access() and check_reg_arg() will need a lot of changes in test_verifier's tests because of the difference in verifier's error message. Thus, the patch here is to save the state->regs[dst_regno].subreg_def first in check_stack_read_fixed_off(). There are cases that the verifier needs to scrub the spilled slot from STACK_SPILL to STACK_MISC. After this patch the spill is not always in 8 bytes now, so it can no longer assume the other 7 bytes are always marked as STACK_SPILL. In particular, the scrub needs to avoid marking an uninitialized byte from STACK_INVALID to STACK_MISC. Otherwise, the verifier will incorrectly accept bpf program reading uninitialized bytes from the stack. A new helper scrub_spilled_slot() is created for this purpose. [1]: https://reviews.llvm.org/D109073Signed-off-by:
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Martin KaFai Lau authored
Every 8 bytes of the stack is tracked by a bpf_stack_state. Within each bpf_stack_state, there is a 'u8 slot_type[8]' to track the type of each byte. Verifier tests slot_type[0] == STACK_SPILL to decide if the spilled reg state is saved. Verifier currently only saves the reg state if the whole 8 bytes are spilled to the stack, so checking the slot_type[7] is the same as checking slot_type[0]. The later patch will allow verifier to save the bounded scalar reg also for <8 bytes spill. There is a llvm patch [1] to ensure the <8 bytes spill will be 8-byte aligned, so checking slot_type[7] instead of slot_type[0] is required. While at it, this patch refactors the slot_type[0] == STACK_SPILL test into a new function is_spilled_reg() and change the slot_type[0] check to slot_type[7] check in there also. [1] https://reviews.llvm.org/D109073Signed-off-by:
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- 24 Sep, 2021 1 commit
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Yonghong Song authored
With clang build kernel (adding LLVM=1 to kernel and selftests/bpf build command line), I hit the following test failure: $ ./test_progs -t btf_dump ... btf_dump_data:PASS:ensure expected/actual match 0 nsec btf_dump_data:FAIL:find type id unexpected find type id: actual -2 < expected 0 btf_dump_data:FAIL:find type id unexpected find type id: actual -2 < expected 0 test_btf_dump_int_data:FAIL:dump __int128 unexpected error: -2 (errno 2) #15/9 btf_dump/btf_dump: int_data:FAIL Further analysis showed gcc build kernel has type "__int128" in dwarf/BTF and it doesn't exist in clang build kernel. Code searching for kernel code found the following: arch/s390/include/asm/types.h: unsigned __int128 pair; crypto/ecc.c: unsigned __int128 m = (unsigned __int128)left * right; include/linux/math64.h: return (u64)(((unsigned __int128)a * mul) >> shift); include/linux/math64.h: return (u64)(((unsigned __int128)a * mul) >> shift); lib/ubsan.h:typedef __int128 s_max; lib/ubsan.h:typedef unsigned __int128 u_max; In my case, CONFIG_UBSAN is not enabled. Even if we only have "unsigned __int128" in the code, somehow gcc still put "__int128" in dwarf while clang didn't. Hence current test works fine for gcc but not for clang. Enabling CONFIG_UBSAN is an option to provide __int128 type into dwarf reliably for both gcc and clang, but not everybody enables CONFIG_UBSAN in their kernel build. So the best choice is to use "unsigned __int128" type which is available in both clang and gcc build kernels. But clang and gcc dwarf encoded names for "unsigned __int128" are different: [$ ~] cat t.c unsigned __int128 a; [$ ~] gcc -g -c t.c && llvm-dwarfdump t.o | grep __int128 DW_AT_type (0x00000031 "__int128 unsigned") DW_AT_name ("__int128 unsigned") [$ ~] clang -g -c t.c && llvm-dwarfdump t.o | grep __int128 DW_AT_type (0x00000033 "unsigned __int128") DW_AT_name ("unsigned __int128") The test change in this patch tries to test type name before doing actual test. Signed-off-by:Yonghong Song <yhs@fb.com> Signed-off-by:
Alan Maguire <alan.maguire@oracle.com> Link: https://lore.kernel.org/bpf/20210924025856.2192476-1-yhs@fb.com
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- 22 Sep, 2021 1 commit
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Alexei Starovoitov authored
Document and clarify BPF licensing. Signed-off-by:
Simon Horman <simon.horman@corigine.com> Acked-by:
Joe Stringer <joe@cilium.io> Acked-by:
Lorenz Bauer <lmb@cloudflare.com> Acked-by:
Dave Thaler <dthaler@microsoft.com> Acked-by:
Stephen Hemminger <stephen@networkplumber.org> Acked-by:
Jesper Dangaard Brouer <brouer@redhat.com> Acked-by:
KP Singh <kpsingh@kernel.org> Link: https://lore.kernel.org/bpf/20210917230034.51080-1-alexei.starovoitov@gmail.com
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