bpf: Rename BPF_XADD and prepare to encode other atomics in .imm

A subsequent patch will add additional atomic operations. These new
operations will use the same opcode field as the existing XADD, w

bpf: Rename BPF_XADD and prepare to encode other atomics in .imm

A subsequent patch will add additional atomic operations. These new
operations will use the same opcode field as the existing XADD, with
the immediate discriminating different operations.

In preparation, rename the instruction mode BPF_ATOMIC and start
calling the zero immediate BPF_ADD.

This is possible (doesn't break existing valid BPF progs) because the
immediate field is currently reserved MBZ and BPF_ADD is zero.

All uses are removed from the tree but the BPF_XADD definition is
kept around to avoid breaking builds for people including kernel
headers.

Signed-off-by: Brendan Jackman <jackmanb@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Björn Töpel <bjorn.topel@gmail.com>
Link: https://lore.kernel.org/bpf/20210114181751.768687-5-jackmanb@google.com

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nfp: bpf: eliminate zero extension code-gen

This patch eliminate zero extension code-gen for instructions including
both alu and load/store. The only exception is for ctx load, because
offload targe

nfp: bpf: eliminate zero extension code-gen

This patch eliminate zero extension code-gen for instructions including
both alu and load/store. The only exception is for ctx load, because
offload target doesn't go through host ctx convert logic so we do
customized load and ignores zext flag set by verifier.

Cc: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Jiong Wang <jiong.wang@netronome.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

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nfp: bpf: support removing dead code

Add a verifier callback to the nfp JIT to remove the instructions
the verifier deemed to be dead.

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
R

nfp: bpf: support removing dead code

Add a verifier callback to the nfp JIT to remove the instructions
the verifier deemed to be dead.

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Quentin Monnet <quentin.monnet@netronome.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

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nfp: bpf: support optimizing dead branches

Verifier will now optimize out branches to dead code, implement
the replace_insn callback to take advantage of that optimization.

Signed-off-by: Jakub Kic

nfp: bpf: support optimizing dead branches

Verifier will now optimize out branches to dead code, implement
the replace_insn callback to take advantage of that optimization.

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Quentin Monnet <quentin.monnet@netronome.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

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nfp: bpf: save original program length

Instead of passing env->prog->len around, and trying to adjust
for optimized out instructions just save the initial number
of instructions in struct nfp_prog.

nfp: bpf: save original program length

Instead of passing env->prog->len around, and trying to adjust
for optimized out instructions just save the initial number
of instructions in struct nfp_prog.

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Quentin Monnet <quentin.monnet@netronome.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

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nfp: bpf: move nfp_bpf_analyzer_ops from verifier.c to offload.c

We are about to add several new callbacks to the struct, all of them
defined in offload.c. Move the struct bpf_prog_offload_ops objec

nfp: bpf: move nfp_bpf_analyzer_ops from verifier.c to offload.c

We are about to add several new callbacks to the struct, all of them
defined in offload.c. Move the struct bpf_prog_offload_ops object in
that file. As a consequence, nfp_verify_insn() and nfp_finalize() can no
longer be static.

Signed-off-by: Quentin Monnet <quentin.monnet@netronome.com>
Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

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nfp: bpf: double check vNIC capabilities after object sharing

Program translation stage checks that program can be offloaded to
the netdev which was passed during the load (bpf_attr->prog_ifindex).

nfp: bpf: double check vNIC capabilities after object sharing

Program translation stage checks that program can be offloaded to
the netdev which was passed during the load (bpf_attr->prog_ifindex).
After program sharing was introduced, however, the netdev on which
program is loaded can theoretically be different, and therefore
we should recheck the program size and max stack size at load time.

This was found by code inspection, AFAIK today all vNICs have
identical caps.

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Quentin Monnet <quentin.monnet@netronome.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

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nfp: bpf: protect against mis-initializing atomic counters

Atomic operations on the NFP are currently always in big endian.
The driver keeps track of regions of memory storing atomic values
and byte

nfp: bpf: protect against mis-initializing atomic counters

Atomic operations on the NFP are currently always in big endian.
The driver keeps track of regions of memory storing atomic values
and byte swaps them accordingly. There are corner cases where
the map values may be initialized before the driver knows they
are used as atomic counters. This can happen either when the
datapath is performing the update and the stack contents are
unknown or when map is updated before the program which will
use it for atomic values is loaded.

To avoid situation where user initializes the value to 0 1 2 3
and then after loading a program which uses the word as an atomic
counter starts reading 3 2 1 0 - only allow atomic counters to be
initialized to endian-neutral values.

For updates from the datapath the stack information may not be
as precise, so just allow initializing such values to 0.

Example code which would break:
struct bpf_map_def SEC("maps") rxcnt = {
.type = BPF_MAP_TYPE_HASH,
.key_size = sizeof(__u32),
.value_size = sizeof(__u64),
.max_entries = 1,
};

int xdp_prog1()
{
__u64 nonzeroval = 3;
__u32 key = 0;
__u64 *value;

value = bpf_map_lookup_elem(&rxcnt, &key);
if (!value)
bpf_map_update_elem(&rxcnt, &key, &nonzeroval, BPF_ANY);
else
__sync_fetch_and_add(value, 1);

return XDP_PASS;
}

$ offload bpftool map dump
key: 00 00 00 00 value: 00 00 00 03 00 00 00 00

should be:

$ offload bpftool map dump
key: 00 00 00 00 value: 03 00 00 00 00 00 00 00

Reported-by: David Beckett <david.beckett@netronome.com>
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Quentin Monnet <quentin.monnet@netronome.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

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nfp: replace long license headers with SPDX

Replace the repeated license text with SDPX identifiers.
While at it bump the Copyright dates for files we touched
this year.

Signed-off-by: Edwin Peer <

nfp: replace long license headers with SPDX

Replace the repeated license text with SDPX identifiers.
While at it bump the Copyright dates for files we touched
this year.

Signed-off-by: Edwin Peer <edwin.peer@netronome.com>
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Nic Viljoen <nick.viljoen@netronome.com>
Reviewed-by: Simon Horman <simon.horman@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

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nfp: bpf: support pointers to other stack frames for BPF-to-BPF calls

Mark instructions that use pointers to areas in the stack outside of the
current stack frame, and process them accordingly in me

nfp: bpf: support pointers to other stack frames for BPF-to-BPF calls

Mark instructions that use pointers to areas in the stack outside of the
current stack frame, and process them accordingly in mem_op_stack().
This way, we also support BPF-to-BPF calls where the caller passes a
pointer to data in its own stack frame to the callee (typically, when
the caller passes an address to one of its local variables located in
the stack, as an argument).

Thanks to Jakub and Jiong for figuring out how to deal with this case,
I just had to turn their email discussion into this patch.

Suggested-by: Jiong Wang <jiong.wang@netronome.com>
Suggested-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Quentin Monnet <quentin.monnet@netronome.com>
Reviewed-by: Jiong Wang <jiong.wang@netronome.com>
Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

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nfp: bpf: optimise save/restore for R6~R9 based on register usage

When pre-processing the instructions, it is trivial to detect what
subprograms are using R6, R7, R8 or R9 as destination registers.

nfp: bpf: optimise save/restore for R6~R9 based on register usage

When pre-processing the instructions, it is trivial to detect what
subprograms are using R6, R7, R8 or R9 as destination registers. If a
subprogram uses none of those, then we do not need to jump to the
subroutines dedicated to saving and restoring callee-saved registers in
its prologue and epilogue.

This patch introduces detection of callee-saved registers in subprograms
and prevents the JIT from adding calls to those subroutines whenever we
can: we save some instructions in the translated program, and some time
at runtime on BPF-to-BPF calls and returns.

If no subprogram needs to save those registers, we can avoid appending
the subroutines at the end of the program.

Signed-off-by: Quentin Monnet <quentin.monnet@netronome.com>
Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

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nfp: bpf: account for additional stack usage when checking stack limit

Offloaded programs using BPF-to-BPF calls use the stack to store the
return address when calling into a subprogram. Callees als

nfp: bpf: account for additional stack usage when checking stack limit

Offloaded programs using BPF-to-BPF calls use the stack to store the
return address when calling into a subprogram. Callees also need some
space to save eBPF registers R6 to R9. And contrarily to kernel
verifier, we align stack frames on 64 bytes (and not 32). Account for
all this when checking the stack size limit before JIT-ing the program.
This means we have to recompute maximum stack usage for the program, we
cannot get the value from the kernel.

In addition to adapting the checks on stack usage, move them to the
finalize() callback, now that we have it and because such checks are
part of the verification step rather than translation.

Signed-off-by: Quentin Monnet <quentin.monnet@netronome.com>
Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

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nfp: bpf: add main logics for BPF-to-BPF calls support in nfp driver

This is the main patch for the logics of BPF-to-BPF calls in the nfp
driver.

The functions called on BPF_JUMP | BPF_CALL and BPF

nfp: bpf: add main logics for BPF-to-BPF calls support in nfp driver

This is the main patch for the logics of BPF-to-BPF calls in the nfp
driver.

The functions called on BPF_JUMP | BPF_CALL and BPF_JUMP | BPF_EXIT were
used to call helpers and exit from the program, respectively; make them
usable for calling into, or returning from, a BPF subprogram as well.

For all calls, push the return address as well as the callee-saved
registers (R6 to R9) to the stack, and pop them upon returning from the
calls. In order to limit the overhead in terms of instruction number,
this is done through dedicated subroutines. Jumping to the callee
actually consists in jumping to the subroutine, that "returns" to the
callee: this will require some fixup for passing the address in a later
patch. Similarly, returning consists in jumping to the subroutine, which
pops registers and then return directly to the caller (but no fixup is
needed here).

Return to the caller is performed with the RTN instruction newly added
to the JIT.

For the few steps where we need to know what subprogram an instruction
belongs to, the struct nfp_insn_meta is extended with a new subprog_idx
field.

Note that checks on the available stack size, to take into account the
additional requirements associated to BPF-to-BPF calls (storing R6-R9
and return addresses), are added in a later patch.

Signed-off-by: Quentin Monnet <quentin.monnet@netronome.com>
Signed-off-by: Jiong Wang <jiong.wang@netronome.com>
Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

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nfp: bpf: ignore helper-related checks for BPF calls in nfp verifier

The checks related to eBPF helper calls are performed each time the nfp
driver meets a BPF_JUMP | BPF_CALL instruction. However,

nfp: bpf: ignore helper-related checks for BPF calls in nfp verifier

The checks related to eBPF helper calls are performed each time the nfp
driver meets a BPF_JUMP | BPF_CALL instruction. However, these checks
are not relevant for BPF-to-BPF call (same instruction code, different
value in source register), so just skip the checks for such calls.

While at it, rename the function that runs those checks to make it clear
they apply to _helper_ calls only.

Signed-off-by: Quentin Monnet <quentin.monnet@netronome.com>
Reviewed-by: Jiong Wang <jiong.wang@netronome.com>
Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

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nfp: bpf: copy eBPF subprograms information from kernel verifier

In order to support BPF-to-BPF calls in offloaded programs, the nfp
driver must collect information about the distinct subprograms: n

nfp: bpf: copy eBPF subprograms information from kernel verifier

In order to support BPF-to-BPF calls in offloaded programs, the nfp
driver must collect information about the distinct subprograms: namely,
the number of subprograms composing the complete program and the stack
depth of those subprograms. The latter in particular is non-trivial to
collect, so we copy those elements from the kernel verifier via the
newly added post-verification hook. The struct nfp_prog is extended to
store this information. Stack depths are stored in an array of dedicated
structs.

Subprogram start indexes are not collected. Instead, meta instructions
associated to the start of a subprogram will be marked with a flag in a
later patch.

Signed-off-by: Quentin Monnet <quentin.monnet@netronome.com>
Reviewed-by: Jiong Wang <jiong.wang@netronome.com>
Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

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bpf: add verifier callback to get stack usage info for offloaded progs

In preparation for BPF-to-BPF calls in offloaded programs, add a new
function attribute to the struct bpf_prog_offload_ops so t

bpf: add verifier callback to get stack usage info for offloaded progs

In preparation for BPF-to-BPF calls in offloaded programs, add a new
function attribute to the struct bpf_prog_offload_ops so that drivers
supporting eBPF offload can hook at the end of program verification, and
potentially extract information collected by the verifier.

Implement a minimal callback (returning 0) in the drivers providing the
structs, namely netdevsim and nfp.

This will be useful in the nfp driver, in later commits, to extract the
number of subprograms as well as the stack depth for those subprograms.

Signed-off-by: Quentin Monnet <quentin.monnet@netronome.com>
Reviewed-by: Jiong Wang <jiong.wang@netronome.com>
Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

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nfp: bpf: xdp_adjust_tail support

Add support for adjust_tail. There are no FW changes needed but add
a FW capability just in case there would be any issue with previously
released FW, or we will h

nfp: bpf: xdp_adjust_tail support

Add support for adjust_tail. There are no FW changes needed but add
a FW capability just in case there would be any issue with previously
released FW, or we will have to change the ABI in the future.

The helper is trivial and shouldn't be used too often so just inline
the body of the function. We add the delta to locally maintained
packet length register and check for overflow, since add of negative
value must overflow if result is positive. Note that if delta of 0
would be allowed in the kernel this trick stops working and we need
one more instruction to compare lengths before and after the change.

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Quentin Monnet <quentin.monnet@netronome.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

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nfp: bpf: support u32 divide using reciprocal_div.h

NFP doesn't have integer divide instruction, this patch use reciprocal
algorithm (the basic one, reciprocal_div) to emulate it.

For each u32 divi

nfp: bpf: support u32 divide using reciprocal_div.h

NFP doesn't have integer divide instruction, this patch use reciprocal
algorithm (the basic one, reciprocal_div) to emulate it.

For each u32 divide, we would need 11 instructions to finish the operation.

7 (for multiplication) + 4 (various ALUs) = 11

Given NFP only supports multiplication no bigger than u32, we'd require
divisor and dividend no bigger than that as well.

Also eBPF doesn't support signed divide and has enforced this on C language
level by failing compilation. However LLVM assembler hasn't enforced this,
so it is possible for negative constant to leak in as a BPF_K operand
through assembly code, we reject such cases as well.

Signed-off-by: Jiong Wang <jiong.wang@netronome.com>
Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

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nfp: bpf: support u16 and u32 multiplications

NFP supports u16 and u32 multiplication. Multiplication is done 8-bits per
step, therefore we need 2 steps for u16 and 4 steps for u32.

We also need on

nfp: bpf: support u16 and u32 multiplications

NFP supports u16 and u32 multiplication. Multiplication is done 8-bits per
step, therefore we need 2 steps for u16 and 4 steps for u32.

We also need one start instruction to initialize the sequence and one or
two instructions to fetch the result depending on either you need the high
halve of u32 multiplication.

For ALU64, if either operand is beyond u32's value range, we reject it. One
thing to note, if the source operand is BPF_K, then we need to check "imm"
field directly, and we'd reject it if it is negative. Because for ALU64,
"imm" (with s32 type) is expected to be sign extended to s64 which NFP mul
doesn't support. For ALU32, it is fine for "imm" be negative though,
because the result is 32-bits and here is no difference on the low halve
of result for signed/unsigned mul, so we will get correct result.

Signed-off-by: Jiong Wang <jiong.wang@netronome.com>
Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

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nfp: bpf: copy range info for all operands of all ALU operations

NFP verifier hook is coping range information of the shift amount for
indirect shift operation so optimized shift sequences could be

nfp: bpf: copy range info for all operands of all ALU operations

NFP verifier hook is coping range information of the shift amount for
indirect shift operation so optimized shift sequences could be generated.

We want to use range info to do more things. For example, to decide whether
multiplication and divide are supported on the given range.

This patch simply let NFP verifier hook to copy range info for all operands
of all ALU operands.

Signed-off-by: Jiong Wang <jiong.wang@netronome.com>
Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

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nfp: bpf: rename umin/umax to umin_src/umax_src

The two fields are a copy of umin and umax info of bpf_insn->src_reg
generated by verifier.

Rename to make their meaning clear.

Signed-off-by: Jiong

nfp: bpf: rename umin/umax to umin_src/umax_src

The two fields are a copy of umin and umax info of bpf_insn->src_reg
generated by verifier.

Rename to make their meaning clear.

Signed-off-by: Jiong Wang <jiong.wang@netronome.com>
Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

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nfp: bpf: support logic indirect shifts (BPF_[L|R]SH | BPF_X)

For indirect shifts, shift amount is not specified as constant, NFP needs
to get the shift amount through the low 5 bits of source A ope

nfp: bpf: support logic indirect shifts (BPF_[L|R]SH | BPF_X)

For indirect shifts, shift amount is not specified as constant, NFP needs
to get the shift amount through the low 5 bits of source A operand in
PREV_ALU, therefore extra instructions are needed compared with shifts by
constants.

Because NFP is 32-bit, so we are using register pair for 64-bit shifts and
therefore would need different instruction sequences depending on whether
shift amount is less than 32 or not.

NFP branch-on-bit-test instruction emitter is added by this patch and is
used for efficient runtime check on shift amount. We'd think the shift
amount is less than 32 if bit 5 is clear and greater or equal than 32
otherwise. Shift amount is greater than or equal to 64 will result in
undefined behavior.

This patch also use range info to avoid generating unnecessary runtime code
if we are certain shift amount is less than 32 or not.

Signed-off-by: Jiong Wang <jiong.wang@netronome.com>
Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

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nfp: bpf: support setting the RX queue index

BPF has access to all internal FW datapath structures. Including
the structure containing RX queue selection. With little coordination
with the datapat

nfp: bpf: support setting the RX queue index

BPF has access to all internal FW datapath structures. Including
the structure containing RX queue selection. With little coordination
with the datapath we can let the offloaded BPF select the RX queue.
We just need a way to tell the datapath that queue selection has already
been done and it shouldn't overwrite it. Define a bit to tell datapath
BPF already selected a queue (QSEL_SET), if the selected queue is not
enabled (>= number of enabled queues) datapath will perform normal RSS.

BPF queue selection on the NIC can be used to replace standard
datapath RSS with fully programmable BPF/XDP RSS.

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Quentin Monnet <quentin.monnet@netronome.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

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nfp: bpf: rewrite map pointers with NFP TIDs

Kernel will now replace map fds with actual pointer before
calling the offload prepare. We can identify those pointers
and replace them with NFP table I

nfp: bpf: rewrite map pointers with NFP TIDs

Kernel will now replace map fds with actual pointer before
calling the offload prepare. We can identify those pointers
and replace them with NFP table IDs instead of loading the
table ID in code generated for CALL instruction.

This allows us to support having the same CALL being used with
different maps.

Since we don't want to change the FW ABI we still need to
move the TID from R1 to portion of R0 before the jump.

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Quentin Monnet <quentin.monnet@netronome.com>
Reviewed-by: Jiong Wang <jiong.wang@netronome.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

show more ...

nfp: bpf: perf event output helpers support

Add support for the perf_event_output family of helpers.

The implementation on the NFP will not match the host code exactly.
The state of the host map an

nfp: bpf: perf event output helpers support

Add support for the perf_event_output family of helpers.

The implementation on the NFP will not match the host code exactly.
The state of the host map and rings is unknown to the device, hence
device can't return errors when rings are not installed. The device
simply packs the data into a firmware notification message and sends
it over to the host, returning success to the program.

There is no notion of a host CPU on the device when packets are being
processed. Device will only offload programs which set BPF_F_CURRENT_CPU.
Still, if map index doesn't match CPU no error will be returned (see
above).

Dropped/lost firmware notification messages will not cause "lost
events" event on the perf ring, they are only visible via device
error counters.

Firmware notification messages may also get reordered in respect
to the packets which caused their generation.

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Quentin Monnet <quentin.monnet@netronome.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

show more ...