From a66886fe6c24ebeeb6dc10fbd9b75158029eacf7 Mon Sep 17 00:00:00 2001 From: Daniel Borkmann Date: Fri, 22 Nov 2019 21:07:57 +0100 Subject: bpf: Add initial poke descriptor table for jit images Add initial poke table data structures and management to the BPF prog that can later be used by JITs. Also add an instance of poke specific data for tail call maps; plan for later work is to extend this also for BPF static keys. Signed-off-by: Daniel Borkmann Signed-off-by: Alexei Starovoitov Acked-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/1db285ec2ea4207ee0455b3f8e191a4fc58b9ade.1574452833.git.daniel@iogearbox.net --- kernel/bpf/core.c | 34 ++++++++++++++++++++++++++++++++++ 1 file changed, 34 insertions(+) (limited to 'kernel') diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c index 07af9c1d9cf1..608b7085e0c9 100644 --- a/kernel/bpf/core.c +++ b/kernel/bpf/core.c @@ -256,6 +256,7 @@ void __bpf_prog_free(struct bpf_prog *fp) { if (fp->aux) { free_percpu(fp->aux->stats); + kfree(fp->aux->poke_tab); kfree(fp->aux); } vfree(fp); @@ -756,6 +757,39 @@ int bpf_get_kallsym(unsigned int symnum, unsigned long *value, char *type, return ret; } +int bpf_jit_add_poke_descriptor(struct bpf_prog *prog, + struct bpf_jit_poke_descriptor *poke) +{ + struct bpf_jit_poke_descriptor *tab = prog->aux->poke_tab; + static const u32 poke_tab_max = 1024; + u32 slot = prog->aux->size_poke_tab; + u32 size = slot + 1; + + if (size > poke_tab_max) + return -ENOSPC; + if (poke->ip || poke->ip_stable || poke->adj_off) + return -EINVAL; + + switch (poke->reason) { + case BPF_POKE_REASON_TAIL_CALL: + if (!poke->tail_call.map) + return -EINVAL; + break; + default: + return -EINVAL; + } + + tab = krealloc(tab, size * sizeof(*poke), GFP_KERNEL); + if (!tab) + return -ENOMEM; + + memcpy(&tab[slot], poke, sizeof(*poke)); + prog->aux->size_poke_tab = size; + prog->aux->poke_tab = tab; + + return slot; +} + static atomic_long_t bpf_jit_current; /* Can be overridden by an arch's JIT compiler if it has a custom, -- cgit v1.2.3-70-g09d2