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powerpc32/bpf: Fix codegen for bpf-to-bpf calls

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Pad instructions emitted for BPF_CALL so that the number of instructions
generated does not change for different function addresses. This is
especially important for calls to other bpf functions, whose address
will only be known during extra pass.

Fixes: 51c66ad849a703 ("powerpc/bpf: Implement extended BPF on PPC32")
Cc: stable@vger.kernel.org # v5.13+
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/52d8fe51f7620a6f27f377791564d79d75463576.1641468127.git.naveen.n.rao@linux.vnet.ibm.com
This commit is contained in:
Naveen N. Rao 2022-01-06 17:15:06 +05:30 committed by Michael Ellerman
parent b992f01e66
commit fab07611fb
1 changed files with 3 additions and 0 deletions
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3
arch/powerpc/net/bpf_jit_comp32.c
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@ -191,6 +191,9 @@ void bpf_jit_emit_func_call_rel(u32 *image, struct codegen_context *ctx, u64 fun
if (image && rel < 0x2000000 && rel >= -0x2000000) {
PPC_BL_ABS(func);
EMIT(PPC_RAW_NOP());
EMIT(PPC_RAW_NOP());
EMIT(PPC_RAW_NOP());
} else {
/* Load function address into r0 */
EMIT(PPC_RAW_LIS(_R0, IMM_H(func)));