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authorTony Ambardar <tony.ambardar@gmail.com>2022-06-17 13:57:34 +0300
committerDaniel Borkmann <daniel@iogearbox.net>2022-06-21 19:52:04 +0300
commit95acd8817e66d031d2e6ee7def3f1e1874819317 (patch)
treef42808f3e806be15132e6978a1f2501eef59372b /kernel/bpf/core.c
parentb40b414ec8d971be0b2f6485c3a039b0fa7f078c (diff)
bpf, x64: Add predicate for bpf2bpf with tailcalls support in JIT
The BPF core/verifier is hard-coded to permit mixing bpf2bpf and tail calls for only x86-64. Change the logic to instead rely on a new weak function 'bool bpf_jit_supports_subprog_tailcalls(void)', which a capable JIT backend can override. Update the x86-64 eBPF JIT to reflect this. Signed-off-by: Tony Ambardar <Tony.Ambardar@gmail.com> [jakub: drop MIPS bits and tweak patch subject] Signed-off-by: Jakub Sitnicki <jakub@cloudflare.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20220617105735.733938-2-jakub@cloudflare.com
Diffstat (limited to 'kernel/bpf/core.c')
-rw-r--r--kernel/bpf/core.c6
1 files changed, 6 insertions, 0 deletions
diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c
index b5ffebcce6cc..f023cb399e3f 100644
--- a/kernel/bpf/core.c
+++ b/kernel/bpf/core.c
@@ -2729,6 +2729,12 @@ bool __weak bpf_jit_needs_zext(void)
return false;
}
+/* Return TRUE if the JIT backend supports mixing bpf2bpf and tailcalls. */
+bool __weak bpf_jit_supports_subprog_tailcalls(void)
+{
+ return false;
+}
+
bool __weak bpf_jit_supports_kfunc_call(void)
{
return false;