powerpc: Fix BPF_JIT code to link with multiple TOCs

If the kernel is big enough (eg. allyesconfig), the linker may need to
switch TOCs when calling from the BPF JIT code out to the external
helpers (skb_copy_bits() & bpf_internal_load_pointer_neg_helper()).

In order to do that we need to leave space after the bl for the linker
to insert a reload of our TOC pointer.

Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Acked-by: Matt Evans <matt@ozlabs.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

diff --git a/arch/powerpc/net/bpf_jit_64.S b/arch/powerpc/net/bpf_jit_64.S
index 55ba385..7d3a3b5 100644 (file)
--- a/arch/powerpc/net/bpf_jit_64.S
+++ b/arch/powerpc/net/bpf_jit_64.S
@@ -105,6 +105,7 @@ sk_load_byte_msh_positive_offset:
        mr      r4, r_addr;                                     \
        li      r6, SIZE;                                       \
        bl      skb_copy_bits;                                  \
+       nop;                                                    \
        /* R3 = 0 on success */                                 \
        addi    r1, r1, BPF_PPC_SLOWPATH_FRAME;                 \
        ld      r0, 16(r1);                                     \
@@ -156,6 +157,7 @@ bpf_slow_path_byte_msh:
        mr      r4, r_addr;                                     \
        li      r5, SIZE;                                       \
        bl      bpf_internal_load_pointer_neg_helper;           \
+       nop;                                                    \
        /* R3 != 0 on success */                                \
        addi    r1, r1, BPF_PPC_SLOWPATH_FRAME;                 \
        ld      r0, 16(r1);                                     \