Johan Almbladh 9b6b7054dd bpf, arm: Fix register clobbering in div/mod implementation ... [ Upstream commit 79e3445b38e0cab94264a3894c0c3d57c930b97e ] On ARM CPUs that lack div/mod instructions, ALU32 BPF_DIV and BPF_MOD are implemented using a call to a helper function. Before, the emitted code for those function calls failed to preserve caller-saved ARM registers. Since some of those registers happen to be mapped to BPF registers, it resulted in eBPF register values being overwritten. This patch emits code to push and pop the remaining caller-saved ARM registers r2-r3 into the stack during the div/mod function call. ARM registers r0-r1 are used as arguments and return value, and those were already saved and restored correctly. Fixes: 39c13c204b ("arm: eBPF JIT compiler") Signed-off-by: Johan Almbladh <johan.almbladh@anyfinetworks.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: Sasha Levin <sashal@kernel.org>		2021-10-13 10:10:51 +02:00
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bpf_jit_32.c	bpf, arm: Fix register clobbering in div/mod implementation	2021-10-13 10:10:51 +02:00
bpf_jit_32.h
Makefile