Commit 204c6287 authored by Alexei Starovoitov's avatar Alexei Starovoitov Committed by Andrii Nakryiko
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bpf: Add helper macro bpf_addr_space_cast() 



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.

Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
Signed-off-by: default avatarAndrii Nakryiko <andrii@kernel.org>
Acked-by: default avatarKumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/bpf/20240308010812.89848-12-alexei.starovoitov@gmail.com
parent 2e7ba4f8

tools/testing/selftests/bpf/bpf_experimental.h

+43 −0
Original line number Diff line number Diff line
@@ -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