Re: [PATCH 1/1 perf-tools] tools riscv: Include fence.h from the same directory barrier.h lives

[Charlie Jenkins <charlie@rivosinc.com>]

On Tue, Nov 26, 2024 at 06:23:41PM -0300, Arnaldo Carvalho de Melo wrote:
> When cross building perf to riscv I noticed that it isn't finding the
> asm/fence.h file included from tools/arch/riscv/include/asm/barrier.h,
> since both live in the same directory, load it from there instead of
> from asm/fence.h, fixing the libbpf build in such environment:
> 
>   perfbuilder@number:~$ time dm ubuntu:22.04-x-riscv64
>      1     4.32 ubuntu:22.04-x-riscv64        : FAIL gcc version 11.4.0 (Ubuntu 11.4.0-1ubuntu1~22.04)
>                        from mmap.c:7:
>       /git/perf-6.12.0-rc6/tools/include/asm/../../arch/riscv/include/asm/barrier.h:13:10: fatal error: asm/fence.h: No such file or directory
>          13 | #include <asm/fence.h>
>             |          ^~~~~~~~~~~~~
>       compilation terminated.
>   <SNIP other similar errors>
> 
> This probably should work in other systems where the right asm/fence.h
> is available, but in the above scenario, it fails. Probably we should
> fix the perf build system to find it in tools/arch/riscv/include/asm/,
> but this one-liner should be a stop gap solution till we get there.
> 
> Testing it:
> 
>   perfbuilder@number:~$ time dm ubuntu:22.04-x-riscv64
>      1    21.65 ubuntu:22.04-x-riscv64        : Ok   riscv64-linux-gnu-gcc (Ubuntu 11.4.0-1ubuntu1~22.04) 11.4.0  flex 2.6.4
>   BUILD_TARBALL_HEAD=800d169e2d39e4e81ade326d73ae7c4343c12b45
>   $ git log --oneline -1 800d169e2d39e4e81ade326d73ae7c4343c12b45
>   800d169e2d39e4e8 tools riscv: Include fence.h from the same directory barrier.h lives
>   toolsbuilder@number:~/perf-6.12.0-rc6$ ls -la /tmp/build/perf/perf
>   -rwxr-xr-x. 1 toolsbuilder toolsbuilder 3278728 Nov 26 21:12 /tmp/build/perf/perf
>   toolsbuilder@number:~/perf-6.12.0-rc6$ file /tmp/build/perf/perf
>   /tmp/build/perf/perf: ELF 64-bit LSB pie executable, UCB RISC-V, RVC, double-float ABI, version 1 (SYSV), dynamically linked, interpreter /lib/ld-linux-riscv64-lp64d.so.1, BuildID[sha1]=9b77bbf51da74cee24c6d5fc5814343cc7e9a652, for GNU/Linux 4.15.0, with debug_info, not stripped
>   toolsbuilder@number:~/perf-6.12.0-rc6$
>   toolsbuilder@number:~/perf-6.12.0-rc6$ readelf -d /tmp/build/perf/perf | head
>   Dynamic section at offset 0x242db0 contains 33 entries:
>     Tag        Type                         Name/Value
>    0x0000000000000001 (NEEDED)             Shared library: [libm.so.6]
>    0x0000000000000001 (NEEDED)             Shared library: [libz.so.1]
>    0x0000000000000001 (NEEDED)             Shared library: [libelf.so.1]
>    0x0000000000000001 (NEEDED)             Shared library: [libdw.so.1]
>    0x0000000000000001 (NEEDED)             Shared library: [libc.so.6]
>    0x0000000000000001 (NEEDED)             Shared library: [ld-linux-riscv64-lp64d.so.1]
>    0x0000000000000020 (PREINIT_ARRAY)      0x238740
>   toolsbuilder@number:~/perf-6.12.0-rc6$
> 
> Fixes: 6d74d178fe6eaf61 ("tools: Add riscv barrier implementation")
> Cc: Charlie Jenkins <charlie@rivosinc.com>
> Cc: Palmer Dabbelt <palmer@rivosinc.com>
> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
> ---
>  tools/arch/riscv/include/asm/barrier.h | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/tools/arch/riscv/include/asm/barrier.h b/tools/arch/riscv/include/asm/barrier.h
> index 6997f197086ddf61..e78241632e2f1301 100644
> --- a/tools/arch/riscv/include/asm/barrier.h
> +++ b/tools/arch/riscv/include/asm/barrier.h
> @@ -10,7 +10,7 @@
>  #ifndef _TOOLS_LINUX_ASM_RISCV_BARRIER_H
>  #define _TOOLS_LINUX_ASM_RISCV_BARRIER_H
>  
> -#include <asm/fence.h>
> +#include "fence.h"
>  #include <linux/compiler.h>
>  
>  /* These barriers need to enforce ordering on both devices and memory. */
> -- 
> 2.47.0
> 

We have been trying to get this resolved with a different patch [1], but
getting it picked up was painfully slow and it wasn't picked up into
6.12 for some reason... It is on master now, but it hasn't been
backported yet, I don't know why not. There was another fix here [2]
that is similar to what you have, but [1] was selected instead of it.

[1] https://lore.kernel.org/linux-riscv/172835823300.66789.3704854116445399222.git-patchwork-notify@kernel.org/
[2] https://lore.kernel.org/linux-riscv/mvm5xq44bqh.fsf@suse.de/

- Charlie