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 <[email protected]>
Acked-by: Matt Evans <[email protected]>
Signed-off-by: Benjamin Herrenschmidt <[email protected]>

diff --git a/arch/powerpc/net/bpf_jit_64.S b/arch/powerpc/net/bpf_jit_64.S
index 55ba3855a97f58093ec06f343cde1df2dffbb17b..7d3a3b5619a2b8f2528b61dc7077b4dd84c594d2 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);                                     \