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35607b02db
- fix BPF_LD|ABS|IND from negative offsets: make sure to sign extend lower 32 bits in 64-bit register before calling C helpers from JITed code, otherwise 'int k' argument of bpf_internal_load_pointer_neg_helper() function will be added as large unsigned integer, causing packet size check to trigger and abort the program. It's worth noting that JITed code for 'A = A op K' will affect upper 32 bits differently depending whether K is simm13 or not. Since small constants are sign extended, whereas large constants are stored in temp register and zero extended. That is ok and we don't have to pay a penalty of sign extension for every sethi, since all classic BPF instructions have 32-bit semantics and we only need to set correct upper bits when transitioning from JITed code into C. - though instructions 'A &= 0' and 'A *= 0' are odd, JIT compiler should not optimize them out Signed-off-by: Alexei Starovoitov <ast@plumgrid.com> Signed-off-by: David S. Miller <davem@davemloft.net> |
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| .. | ||
| bpf_jit_asm.S | ||
| bpf_jit_comp.c | ||
| bpf_jit.h | ||
| Makefile | ||