RE: [PATCH] hexagon: Remove CONFIG_HEXAGON_ARCH_VERSION from uapi header

[Brian Cain]

> -----Original Message-----
> From: Thomas Huth <thuth@xxxxxxxxxx>
> Sent: Thursday, October 26, 2023 6:31 AM
> To: Arnd Bergmann <arnd@xxxxxxxx>; linux-hexagon@xxxxxxxxxxxxxxx; Brian
> Cain <bcain@xxxxxxxxxxx>
> Cc: linux-kernel@xxxxxxxxxxxxxxx; Oleg Nesterov <oleg@xxxxxxxxxx>
> Subject: [PATCH] hexagon: Remove CONFIG_HEXAGON_ARCH_VERSION from
> uapi header
> 
> WARNING: This email originated from outside of Qualcomm. Please be wary of
> any links or attachments, and do not enable macros.
> 
> uapi headers should not expose CONFIG switches since they are not
> available in userspace. Fix it in arch/hexagon/include/uapi/asm/user.h
> by always defining the cs0 and cs1 entries instead of pad values.
> 
> Suggested-by: Arnd Bergmann <arnd@xxxxxxxx>
> Signed-off-by: Thomas Huth <thuth@xxxxxxxxxx>
> ---
>  Based-on: <20231025073802.117625-1-thuth@xxxxxxxxxx>
> 
>  Compile tested only (with CONFIG_HEXAGON_ARCH_VERSION set to 2
>  and with CONFIG_HEXAGON_ARCH_VERSION set to 4)
> 
>  arch/hexagon/include/uapi/asm/user.h | 7 +------
>  arch/hexagon/kernel/ptrace.c         | 7 +++++--
>  scripts/headers_install.sh           | 1 -
>  3 files changed, 6 insertions(+), 9 deletions(-)
> 
> diff --git a/arch/hexagon/include/uapi/asm/user.h
> b/arch/hexagon/include/uapi/asm/user.h
> index 7327ec59b22f..abae6a4b5813 100644
> --- a/arch/hexagon/include/uapi/asm/user.h
> +++ b/arch/hexagon/include/uapi/asm/user.h
> @@ -56,15 +56,10 @@ struct user_regs_struct {
>         unsigned long pc;
>         unsigned long cause;
>         unsigned long badva;
> -#if CONFIG_HEXAGON_ARCH_VERSION < 4
> -       unsigned long pad1;  /* pad out to 48 words total */
> -       unsigned long pad2;  /* pad out to 48 words total */
> -       unsigned long pad3;  /* pad out to 48 words total */
> -#else
> +       /* cs0 and cs1 are only available with HEXAGON_ARCH_VERSION >= 4 */
>         unsigned long cs0;
>         unsigned long cs1;
>         unsigned long pad1;  /* pad out to 48 words total */
> -#endif
>  };
> 
>  #endif
> diff --git a/arch/hexagon/kernel/ptrace.c b/arch/hexagon/kernel/ptrace.c
> index 125f19995b76..905b06790ab7 100644
> --- a/arch/hexagon/kernel/ptrace.c
> +++ b/arch/hexagon/kernel/ptrace.c
> @@ -74,7 +74,7 @@ static int genregs_set(struct task_struct *target,
>                    unsigned int pos, unsigned int count,
>                    const void *kbuf, const void __user *ubuf)
>  {
> -       int ret;
> +       int ret, ignore_offset;
>         unsigned long bucket;
>         struct pt_regs *regs = task_pt_regs(target);
> 
> @@ -111,12 +111,15 @@ static int genregs_set(struct task_struct *target,
>  #if CONFIG_HEXAGON_ARCH_VERSION >=4
>         INEXT(&regs->cs0, cs0);
>         INEXT(&regs->cs1, cs1);
> +       ignore_offset = offsetof(struct user_regs_struct, pad1);
> +#else
> +       ignore_offset = offsetof(struct user_regs_struct, cs0);
>  #endif
> 
>         /* Ignore the rest, if needed */
>         if (!ret)
>                 user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
> -                       offsetof(struct user_regs_struct, pad1), -1);
> +                                         ignore_offset, -1);
>         else
>                 return ret;
> 
> diff --git a/scripts/headers_install.sh b/scripts/headers_install.sh
> index c3064ac31003..f7d9b114de8f 100755
> --- a/scripts/headers_install.sh
> +++ b/scripts/headers_install.sh
> @@ -74,7 +74,6 @@
> arch/arc/include/uapi/asm/page.h:CONFIG_ARC_PAGE_SIZE_16K
>  arch/arc/include/uapi/asm/page.h:CONFIG_ARC_PAGE_SIZE_4K
>  arch/arc/include/uapi/asm/swab.h:CONFIG_ARC_HAS_SWAPE
>  arch/arm/include/uapi/asm/ptrace.h:CONFIG_CPU_ENDIAN_BE8
> -arch/hexagon/include/uapi/asm/user.h:CONFIG_HEXAGON_ARCH_VERSION
>  arch/m68k/include/uapi/asm/ptrace.h:CONFIG_COLDFIRE
>  arch/nios2/include/uapi/asm/swab.h:CONFIG_NIOS2_CI_SWAB_NO
>  arch/nios2/include/uapi/asm/swab.h:CONFIG_NIOS2_CI_SWAB_SUPPORT
> --
> 2.41.0

Acked-by: Brian Cain <bcain@xxxxxxxxxxx>