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Saket Kumar BhaskarandMadhavan Srinivasan
b55b6b9ad7
When verifier sees a timed may_goto instruction, it emits a call to arch_bpf_timed_may_goto() with a stack offset in BPF_REG_AX (powerpc64 R12) and expects the refreshed count value to be returned in the same register. The verifier doesn't save or restore any registers before emitting this call. arch_bpf_timed_may_goto() should act as a trampoline to call bpf_check_timed_may_goto() with powerpc64 ELF ABI calling convention. To support this custom calling convention, implement arch_bpf_timed_may_goto() in assembly and make sure BPF caller saved registers are preserved, then call bpf_check_timed_may_goto with the powerpc64 ABI calling convention where first argument and return value both are in R3. Finally, move the result back into BPF_REG_AX(R12) before returning. Also, introduce bpf_jit_emit_func_call() that computes the offset from kernel_toc_addr(), validates that the target and emits the ADDIS/ADDI sequence to load the function address before performing the indirect branch via MTCTR/BCTRL. The existing code in bpf_jit_emit_func_call_rel() is refactored to use this function. Acked-by: Hari Bathini <hbathini@linux.ibm.com> Signed-off-by: Saket Kumar Bhaskar <skb99@linux.ibm.com> Signed-off-by: Madhavan Srinivasan <maddy@linux.ibm.com> Link: https://patch.msgid.link/20260403105016.74775-1-skb99@linux.ibm.com
10 lines
205 B
Makefile
10 lines
205 B
Makefile
# SPDX-License-Identifier: GPL-2.0
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#
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# Arch-specific network modules
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#
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obj-$(CONFIG_BPF_JIT) += bpf_jit_comp.o bpf_jit_comp$(BITS).o
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ifdef CONFIG_PPC64
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obj-$(CONFIG_BPF_JIT) += bpf_timed_may_goto.o
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endif
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