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| H A D | relo_core.c | b58b2b3a Tue Jun 07 01:26:10 CDT 2022 Yonghong Song <yhs@fb.com> libbpf: Fix an error in 64bit relocation value computation
Currently, the 64bit relocation value in the instruction
is computed as follows:
__u64 imm = insn[0].imm + ((__u64)insn[1].imm << 32)
Suppose insn[0].imm = -1 (0xffffffff) and insn[1].imm = 1.
With the above computation, insn[0].imm will first sign-extend
to 64bit -1 (0xffffffffFFFFFFFF) and then add 0x1FFFFFFFF,
producing incorrect value 0xFFFFFFFF. The correct value
should be 0x1FFFFFFFF.
Changing insn[0].imm to __u32 first will prevent 64bit sign
extension and fix the issue. Merging high and low 32bit values
also changed from '+' to '|' to be consistent with other
similar occurences in kernel and libbpf.
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Dave Marchevsky <davemarchevsky@fb.com>
Signed-off-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/r/20220607062610.3717378-1-yhs@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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