Daniel Borkmann d2e4c1e6c2 bpf: Constant map key tracking for prog array pokes ... Add tracking of constant keys into tail call maps. The signature of bpf_tail_call_proto is that arg1 is ctx, arg2 map pointer and arg3 is a index key. The direct call approach for tail calls can be enabled if the verifier asserted that for all branches leading to the tail call helper invocation, the map pointer and index key were both constant and the same. Tracking of map pointers we already do from prior work via c93552c443 ("bpf: properly enforce index mask to prevent out-of-bounds speculation") and 09772d92cd ("bpf: avoid retpoline for lookup/update/ delete calls on maps"). Given the tail call map index key is not on stack but directly in the register, we can add similar tracking approach and later in fixup_bpf_calls() add a poke descriptor to the progs poke_tab with the relevant information for the JITing phase. We internally reuse insn->imm for the rewritten BPF_JMP | BPF_TAIL_CALL instruction in order to point into the prog's poke_tab, and keep insn->imm as 0 as indicator that current indirect tail call emission must be used. Note that publishing to the tracker must happen at the end of fixup_bpf_calls() since adding elements to the poke_tab reallocates its memory, so we need to wait until its in final state. Future work can generalize and add similar approach to optimize plain array map lookups. Difference there is that we need to look into the key value that sits on stack. For clarity in bpf_insn_aux_data, map_state has been renamed into map_ptr_state, so we get map_{ptr,key}_state as trackers. Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Andrii Nakryiko <andriin@fb.com> Link: https://lore.kernel.org/bpf/e8db37f6b2ae60402fa40216c96738ee9b316c32.1574452833.git.daniel@iogearbox.net		2019-11-24 17:04:11 -08:00
..
acpi	cpufreq: Use per-policy frequency QoS	2019-10-21 02:05:21 +02:00
asm-generic	timekeeping/vsyscall: Update VDSO data unconditionally	2019-11-04 23:02:53 +01:00
clocksource
crypto	Merge branch 'next-integrity' of git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity	2019-09-27 19:37:27 -07:00
drm	drm/shmem: Add docbook comments for drm_gem_shmem_object madvise fields	2019-11-06 17:57:42 -06:00
dt-bindings	dt-bindings: net: dp83869: Add TI dp83869 phy	2019-11-14 17:42:43 -08:00
keys
kvm
linux	bpf: Constant map key tracking for prog array pokes	2019-11-24 17:04:11 -08:00
math-emu
media
misc
net	net: inet_is_local_reserved_port() should return bool not int	2019-11-22 16:52:47 -08:00
pcmcia
ras
rdma	RDMA/uverbs: Prevent potential underflow	2019-10-22 15:05:36 -03:00
scsi	SCSI fixes on 20191015	2019-10-15 12:19:08 -07:00
soc	net: mscc: ocelot: convert to use ocelot_port_add_txtstamp_skb()	2019-11-21 14:39:02 -08:00
sound	ASoC: Fixes for v5.4	2019-10-21 14:05:26 +02:00
target
trace	page_pool: Add API to update numa node	2019-11-20 11:47:36 -08:00
uapi	Revert "bpf: Emit audit messages upon successful prog load and unload"	2019-11-23 09:56:02 -08:00
vdso
video
xen	xen: fixes and cleanups for 5.4-rc2	2019-10-04 11:13:09 -07:00
Kbuild	- New Drivers	2019-09-23 19:37:49 -07:00