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

[Thomas Huth <thuth@redhat.com>]

On 29/11/2023 04.42, Brian Cain wrote:
> 
> 
>> -----Original Message-----
>> From: Thomas Huth <thuth@redhat.com>
>> Sent: Thursday, October 26, 2023 6:31 AM
>> To: Arnd Bergmann <arnd@arndb.de>; linux-hexagon@vger.kernel.org; Brian
>> Cain <bcain@quicinc.com>
>> Cc: linux-kernel@vger.kernel.org; Oleg Nesterov <oleg@redhat.com>
>> 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@arndb.de>
>> Signed-off-by: Thomas Huth <thuth@redhat.com>
>> ---
>>   Based-on: <20231025073802.117625-1-thuth@redhat.com>
>>
>>   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@quicinc.com>

Thanks!

Arnd, could you maybe take this patch through your "generic include/asm 
header files" tree?

  Thomas