Re: [PATCH v3 18/26] arm64: Introduce asm/vdso/processor.h

Vincenzo Frascino
2020-03-16T09:42:32Z

Hi Catalin,

you should not really work on Sunday ;-) Joking, thanks for reviewing my patches.

On 3/15/20 6:30 PM, Catalin Marinas wrote:
> On Fri, Mar 13, 2020 at 03:43:37PM +0000, Vincenzo Frascino wrote:
>> --- /dev/null
>> +++ b/arch/arm64/include/asm/vdso/processor.h
>> @@ -0,0 +1,31 @@
>> +/* SPDX-License-Identifier: GPL-2.0-only */
>> +/*
>> + * Copyright (C) 2020 ARM Ltd.
>> + */
>> +#ifndef __ASM_VDSO_PROCESSOR_H
>> +#define __ASM_VDSO_PROCESSOR_H
>> +
>> +#ifndef __ASSEMBLY__
>> +
>> +#include <asm/page-def.h>
>> +
>> +#ifdef CONFIG_COMPAT
>> +#if defined(CONFIG_ARM64_64K_PAGES) && defined(CONFIG_KUSER_HELPERS)
>> +/*
>> + * With CONFIG_ARM64_64K_PAGES enabled, the last page is occupied
>> + * by the compat vectors page.
>> + */
>> +#define TASK_SIZE_32 UL(0x100000000)
>> +#else
>> +#define TASK_SIZE_32 (UL(0x100000000) - PAGE_SIZE)
>> +#endif /* CONFIG_ARM64_64K_PAGES */
>> +#endif /* CONFIG_COMPAT */
>
> Just curious, what's TASK_SIZE_32 used for in the vDSO code? You don't
> seem to move TASK_SIZE.
>

I tried to fine grain the headers as much as I could in order to avoid
unneeded/unwanted inclusions:
* TASK_SIZE_32 is used to verify ABI consistency on vdso32 (please refer to
arch/arm64/kernel/vdso32/vgettimeofday.c).
* TASK_SIZE is not required by the vdso library hence it is not present in
these headers.

--
Regards,
Vincenzo