Re: [PATCH v2] tools/nolibc: add 64-bit parisc support

[Helge Deller <deller@gmx.de>]

On 8/31/26 06:32, Thomas Weißschuh wrote:
> Extend the existing parisc support to also handle 64-bit mode.
> 
> Some peculiarities:
> * The nonstandard ftruncate64 system call requires a workaround.
> * The linker defaults to main() as entry point, which needs to be
>    switched to _start() explicitly.
> * The linker defaults to dynamic linking, which needs to be disabled
>    explicitly.
> * With the default -Os, gcc does not use 64-bit multiplication
>    instructions, requiring libgcc. Use -O2 instead.
> * There is no qemu-user available.
> * CONFIG_COMPAT needs to be disabled to avoid build errors due to a
>    missing 32-bit vDSO compiler.
> 
> Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
> ---
> Changes in v2:
> - Rebase on latest nolibc/for-next.
> - Fix typo in comment.
> - Reorder conditions in run-tests.sh.
> - Fix llvm=1 check in run-tests.sh.
> - Link to v1: https://patch.msgid.link/20260820-nolibc-parisc64-v1-1-067ebe7c8efb@weissschuh.net
> ---
>   tools/include/nolibc/arch-parisc.h             | 26 +++++++++++++++++++++++---
>   tools/include/nolibc/stdlib.h                  |  2 +-
>   tools/testing/selftests/nolibc/Makefile.nolibc |  5 +++++
>   tools/testing/selftests/nolibc/run-tests.sh    | 10 +++++++---
>   4 files changed, 36 insertions(+), 7 deletions(-)
> 
> diff --git a/tools/include/nolibc/arch-parisc.h b/tools/include/nolibc/arch-parisc.h
> index 417043ecbc53..5c595ef88a62 100644
> --- a/tools/include/nolibc/arch-parisc.h
> +++ b/tools/include/nolibc/arch-parisc.h
> @@ -7,9 +7,7 @@
>   #ifndef _NOLIBC_ARCH_PARISC_H
>   #define _NOLIBC_ARCH_PARISC_H
>   
> -#if defined(__LP64__)
> -#error 64-bit not supported
> -#endif
> +#include <linux/unistd.h>
>   
>   #include "compiler.h"
>   #include "crt.h"
> @@ -167,9 +165,15 @@
>   void __attribute__((weak, noreturn)) __nolibc_entrypoint __nolibc_no_stack_protector _start(void)
>   {
>   	__asm__ volatile (
> +#ifdef __LP64__
> +		".import __gp\n"               /* Set up the dp register */
> +		"ldil L%__gp, %dp\n"
> +		"ldo R%__gp(%r27), %dp\n"

change to:
"ldo R%__gp(%dp), %dp\n"

> +#else
>   		".import $global$\n"           /* Set up the dp register */
>   		"ldil L%$global$, %dp\n"
>   		"ldo R%$global$(%r27), %dp\n"

change to:
"ldo R%$global$(%dp), %dp\n"


Helge