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-rw-r--r--arch/x86/net/bpf_jit_comp.c46
1 files changed, 46 insertions, 0 deletions
diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c
index 8c10d9abc239..e89e415aa743 100644
--- a/arch/x86/net/bpf_jit_comp.c
+++ b/arch/x86/net/bpf_jit_comp.c
@@ -3025,3 +3025,49 @@ void arch_bpf_stack_walk(bool (*consume_fn)(void *cookie, u64 ip, u64 sp, u64 bp
#endif
WARN(1, "verification of programs using bpf_throw should have failed\n");
}
+
+void bpf_arch_poke_desc_update(struct bpf_jit_poke_descriptor *poke,
+ struct bpf_prog *new, struct bpf_prog *old)
+{
+ u8 *old_addr, *new_addr, *old_bypass_addr;
+ int ret;
+
+ old_bypass_addr = old ? NULL : poke->bypass_addr;
+ old_addr = old ? (u8 *)old->bpf_func + poke->adj_off : NULL;
+ new_addr = new ? (u8 *)new->bpf_func + poke->adj_off : NULL;
+
+ /*
+ * On program loading or teardown, the program's kallsym entry
+ * might not be in place, so we use __bpf_arch_text_poke to skip
+ * the kallsyms check.
+ */
+ if (new) {
+ ret = __bpf_arch_text_poke(poke->tailcall_target,
+ BPF_MOD_JUMP,
+ old_addr, new_addr);
+ BUG_ON(ret < 0);
+ if (!old) {
+ ret = __bpf_arch_text_poke(poke->tailcall_bypass,
+ BPF_MOD_JUMP,
+ poke->bypass_addr,
+ NULL);
+ BUG_ON(ret < 0);
+ }
+ } else {
+ ret = __bpf_arch_text_poke(poke->tailcall_bypass,
+ BPF_MOD_JUMP,
+ old_bypass_addr,
+ poke->bypass_addr);
+ BUG_ON(ret < 0);
+ /* let other CPUs finish the execution of program
+ * so that it will not possible to expose them
+ * to invalid nop, stack unwind, nop state
+ */
+ if (!ret)
+ synchronize_rcu();
+ ret = __bpf_arch_text_poke(poke->tailcall_target,
+ BPF_MOD_JUMP,
+ old_addr, NULL);
+ BUG_ON(ret < 0);
+ }
+}