From: Daniel Dickman <didickman@gmail.com>
Subject: Re: ld.so/sparc64: fix UA64 relocation mask selection and byte order
To: "Kirill A. Korinsky" <kirill@korins.ky>
Cc: OpenBSD tech <tech@openbsd.org>
Date: Thu, 9 Jul 2026 13:27:14 +0200

Looks like netbsd fixed these comma bug in 2013?

https://github.com/NetBSD/src/commit/c60b2e0b87cfd6205cd7689126f9375f22ff6916

> On Jul 9, 2026, at 12:08 PM, Kirill A. Korinsky <kirill@korins.ky> wrote:
> 
> tech@,
> 
> tb@ continue to test my sparc64-by-llvm diff and he discovered a new issues.
> 
> After some search here and where I think I had spoted two separated issues
> in ld.so for sparc64.
> 
> The first one is missing comma. The relocation mask table is indexed by
> relocation number; the missing separator after the R_SPARC_6 entry shifts
> subsequent initializers, so R_SPARC_UA64 receives the R_SPARC_UA16 mask.
> Restore the table layout, otherwise only the low 16 bits of relocated 64 bit
> pointers survive.
> 
> Ok, the next one is byte order. The unaligned relocation path reconstructs
> the relocation target in SPARC byte order, but writes the adjusted value
> back least significant byte first; this reverses R_SPARC_UA64 results on a
> big endian target. Write the value back in target byte order, so relocated
> function pointers retain their canonical representation.
> 
> Ok?
> 
> Index: libexec/ld.so/sparc64/rtld_machine.c
> ===================================================================
> RCS file: /home/cvs/src/libexec/ld.so/sparc64/rtld_machine.c,v
> diff -u -p -r1.72 rtld_machine.c
> --- libexec/ld.so/sparc64/rtld_machine.c    6 May 2026 08:07:05 -0000    1.72
> +++ libexec/ld.so/sparc64/rtld_machine.c    9 Jul 2026 09:55:55 -0000
> @@ -189,7 +189,7 @@ static const long reloc_target_bitmask[]
>    _BM(22), _BM(10), _BM(22),    /* _PC_HH22, _PC_HM10, _PC_LM22 */
>    _BM(16), _BM(19),        /* _WDISP16, _WDISP19 */
>    -1,                /* GLOB_JMP */
> -    _BM(7), _BM(5), _BM(6)        /* _7, _5, _6 */
> +    _BM(7), _BM(5), _BM(6),        /* _7, _5, _6 */
>    -1, -1,                /* DISP64, PLT64 */
>    _BM(22), _BM(13),        /* HIX22, LOX10 */
>    _BM(22), _BM(10), _BM(13),    /* H44, M44, L44 */
> @@ -328,7 +328,7 @@ resolve_failed:
> 
>            /* Write it back out. */
>            for (i=0; i<size; i++)
> -                ptr[i] = ((tmp >> (8*i)) & 0xff);
> +                ptr[i] = ((tmp >> (8*(size - i - 1))) & 0xff);
>        } else if (RELOC_TARGET_SIZE(type) > 32) {
>            *where &= ~mask;
>            *where |= value;
> 
> 
> --
> wbr, Kirill
>