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powerpc64/bpf elfv1: Do not load TOC before calling functions

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BPF helpers always reside in core kernel and all BPF programs use the
kernel TOC. As such, there is no need to load the TOC before calling
helpers or other BPF functions. Drop code to do the same.

Add a check to ensure we don't proceed if this assumption ever changes
in future.

Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/a3cd3da4d24d95d845cd10382b1af083600c9074.1644834730.git.naveen.n.rao@linux.vnet.ibm.com
This commit is contained in:
Naveen N. Rao
2022-02-14 16:11:42 +05:30
committed by Michael Ellerman
parent b10cb163c4
commit 43d636f8b4
4 changed files with 30 additions and 23 deletions
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4
arch/powerpc/net/bpf_jit_comp.c
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@@ -59,7 +59,9 @@ static int bpf_jit_fixup_addresses(struct bpf_prog *fp, u32 *image,
*/
tmp_idx = ctx->idx;
ctx->idx = addrs[i] / 4;
bpf_jit_emit_func_call_rel(image, ctx, func_addr);
ret = bpf_jit_emit_func_call_rel(image, ctx, func_addr);
if (ret)
return ret;
/*
* Restore ctx->idx here. This is safe as the length