From: Alexei Starovoitov <ast@xxxxxxxxxx>
Introduce helper macro bpf_addr_space_cast() that emits:
rX = rX
instruction with off = BPF_ADDR_SPACE_CAST
and encodes dest and src address_space-s into imm32.
It's useful with older LLVM that doesn't emit this insn automatically.
Acked-by: Kumar Kartikeya Dwivedi <memxor@xxxxxxxxx>
Signed-off-by: Alexei Starovoitov <ast@xxxxxxxxxx>
---
.../testing/selftests/bpf/bpf_experimental.h | 43 +++++++++++++++++++
1 file changed, 43 insertions(+)
diff --git a/tools/testing/selftests/bpf/bpf_experimental.h b/tools/testing/selftests/bpf/bpf_experimental.h
index bc9a0832ae72..a5b9df38c162 100644
--- a/tools/testing/selftests/bpf/bpf_experimental.h
+++ b/tools/testing/selftests/bpf/bpf_experimental.h
@@ -343,6 +343,49 @@ l_true: \
asm volatile("%[reg]=%[reg]"::[reg]"r"((short)var))
#endif
+/* emit instruction:
+ * rX = rX .off = BPF_ADDR_SPACE_CAST .imm32 = (dst_as << 16) | src_as
+ */
+#ifndef bpf_addr_space_cast
+#define bpf_addr_space_cast(var, dst_as, src_as)\
+ asm volatile(".byte 0xBF; \
+ .ifc %[reg], r0; \
+ .byte 0x00; \
+ .endif; \
+ .ifc %[reg], r1; \
+ .byte 0x11; \
+ .endif; \
+ .ifc %[reg], r2; \
+ .byte 0x22; \
+ .endif; \
+ .ifc %[reg], r3; \
+ .byte 0x33; \
+ .endif; \
+ .ifc %[reg], r4; \
+ .byte 0x44; \
+ .endif; \
+ .ifc %[reg], r5; \
+ .byte 0x55; \
+ .endif; \
+ .ifc %[reg], r6; \
+ .byte 0x66; \
+ .endif; \
+ .ifc %[reg], r7; \
+ .byte 0x77; \
+ .endif; \
+ .ifc %[reg], r8; \
+ .byte 0x88; \
+ .endif; \
+ .ifc %[reg], r9; \
+ .byte 0x99; \
+ .endif; \
+ .short %[off]; \
+ .long %[as]" \
+ : [reg]"+r"(var) \
+ : [off]"i"(BPF_ADDR_SPACE_CAST) \
+ , [as]"i"((dst_as << 16) | src_as));
+#endif
+
/* Description
* Assert that a conditional expression is true.
* Returns
--
2.43.0
