[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-Id: <8c1d86e6-7ab9-43ed-8da5-27ebde624d0b@app.fastmail.com>
Date: Sat, 16 Aug 2025 19:37:58 +0200
From: Alex Rønne Petersen <alex@...xrp.com>
To: musl@...ts.openwall.com
Subject: Re: [PATCH] s390x: manually inline __tls_get_addr in __tls_get_offset
On Fri, Jan 24, 2025, at 06:12, Alex Rønne Petersen wrote:
> Calling __tls_get_addr with brasl is not valid since it's a global symbol; doing
> so results in an R_390_PC32DBL relocation error from lld. We could fix this by
> marking __tls_get_addr hidden since it is not part of the s390x ABI, or by using
> a different instruction. However, given its simplicity, it makes more sense to
> just manually inline it into __tls_get_offset for performance.
>
> The patch has been tested by applying to Zig's bundled musl copy and running the
> full Zig test suite under qemu-s390x.
> ---
> src/thread/s390x/__tls_get_offset.s | 20 ++++++++++----------
> 1 file changed, 10 insertions(+), 10 deletions(-)
>
> diff --git a/src/thread/s390x/__tls_get_offset.s
> b/src/thread/s390x/__tls_get_offset.s
> index 8ee92de8..405f118b 100644
> --- a/src/thread/s390x/__tls_get_offset.s
> +++ b/src/thread/s390x/__tls_get_offset.s
> @@ -1,17 +1,17 @@
> .global __tls_get_offset
> .type __tls_get_offset,%function
> __tls_get_offset:
> - stmg %r14, %r15, 112(%r15)
> - aghi %r15, -160
> + ear %r0, %a0
> + sllg %r0, %r0, 32
> + ear %r0, %a1
>
> - la %r2, 0(%r2, %r12)
> - brasl %r14, __tls_get_addr
> + la %r1, 0(%r2, %r12)
>
> - ear %r1, %a0
> - sllg %r1, %r1, 32
> - ear %r1, %a1
> + lg %r3, 0(%r1)
> + sllg %r4, %r3, 3
> + lg %r5, 8(%r0)
> + lg %r2, 0(%r4, %r5)
> + ag %r2, 8(%r1)
> + sgr %r2, %r0
>
> - sgr %r2, %r1
> -
> - lmg %r14, %r15, 272(%r15)
> br %r14
> --
> 2.43.0
Friendly ping.
Regards,
Alex
Powered by blists - more mailing lists
Confused about mailing lists and their use?
Read about mailing lists on Wikipedia
and check out these
guidelines on proper formatting of your messages.
