unimore/kernel-hacking-2024-linux-steffo
unimore/kernel-hacking-2024-linux-steffo
1
Fork 0
Code Pull requests 5 Wiki Activity

powerpc/bpf/32: BPF prog is never called with more than one arg

Browse source 
BPF progs are never called with more than one argument, plus the
tail call count as a second argument when needed.

So, no need to retrieve 9th and 10th argument (5th 64 bits argument)
from the stack in prologue.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/89a200fb45048601475c092c5775294dee3886de.1675245773.git.christophe.leroy@csgroup.eu
This commit is contained in:
Christophe Leroy 2023-02-01 11:04:26 +01:00 committed by Michael Ellerman
parent d084dcf256
commit 7dd0e28487
1 changed files with 0 additions and 6 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

6
arch/powerpc/net/bpf_jit_comp32.c
View file

@ -159,12 +159,6 @@ void bpf_jit_build_prologue(u32 *image, struct codegen_context *ctx)
if (bpf_is_seen_register(ctx, i))
EMIT(PPC_RAW_STW(i, _R1, bpf_jit_stack_offsetof(ctx, i)));
/* If needed retrieve arguments 9 and 10, ie 5th 64 bits arg.*/
if (bpf_is_seen_register(ctx, bpf_to_ppc(BPF_REG_5))) {
EMIT(PPC_RAW_LWZ(bpf_to_ppc(BPF_REG_5) - 1, _R1, BPF_PPC_STACKFRAME(ctx)) + 8);
EMIT(PPC_RAW_LWZ(bpf_to_ppc(BPF_REG_5), _R1, BPF_PPC_STACKFRAME(ctx)) + 12);
}
/* Setup frame pointer to point to the bpf stack area */
if (bpf_is_seen_register(ctx, bpf_to_ppc(BPF_REG_FP))) {
EMIT(PPC_RAW_LI(bpf_to_ppc(BPF_REG_FP) - 1, 0));