Re: [PATCH 07/16] powerpc: mm: Support MAP_BELOW_HINT

Christophe Leroy
2024-08-28T06:35:02Z

Hi Charlie,

Le 28/08/2024 à 07:49, Charlie Jenkins a écrit :
> Add support for MAP_BELOW_HINT to arch_get_mmap_base() and
> arch_get_mmap_end().
>
> Signed-off-by: Charlie Jenkins <charlie@rivosinc.com>
> ---
> arch/powerpc/include/asm/task_size_64.h | 36 +++++++++++++++++++++++++++------
> 1 file changed, 30 insertions(+), 6 deletions(-)
>
> diff --git a/arch/powerpc/include/asm/task_size_64.h b/arch/powerpc/include/asm/task_size_64.h
> index 239b363841aa..a37a5a81365d 100644
> --- a/arch/powerpc/include/asm/task_size_64.h
> +++ b/arch/powerpc/include/asm/task_size_64.h
> @@ -72,12 +72,36 @@
> #define STACK_TOP_MAX TASK_SIZE_USER64
> #define STACK_TOP (is_32bit_task() ? STACK_TOP_USER32 : STACK_TOP_USER64)
>
> -#define arch_get_mmap_base(addr, len, base, flags) \
> - (((addr) > DEFAULT_MAP_WINDOW) ? (base) + TASK_SIZE - DEFAULT_MAP_WINDOW : (base))
> +#define arch_get_mmap_base(addr, len, base, flags) \

This macro looks quite big for a macro, can it be a static inline
function instead ? Same for the other macro below.

> +({ \
> + unsigned long mmap_base; \
> + typeof(flags) _flags = (flags); \
> + typeof(addr) _addr = (addr); \
> + typeof(base) _base = (base); \
> + typeof(len) _len = (len); \
> + unsigned long rnd_gap = DEFAULT_MAP_WINDOW - (_base); \
> + if (_flags & MAP_BELOW_HINT && _addr != 0 && ((_addr + _len) > BIT(VA_BITS - 1)))\
> + mmap_base = (_addr + _len) - rnd_gap; \
> + else \
> + mmap_end = ((_addr > DEFAULT_MAP_WINDOW) ? \
> + _base + TASK_SIZE - DEFAULT_MAP_WINDOW : \
> + _base); \
> + mmap_end; \

mmap_end doesn't exist, did you mean mmap_base ?

> +})
>
> -#define arch_get_mmap_end(addr, len, flags) \
> - (((addr) > DEFAULT_MAP_WINDOW) || \
> - (((flags) & MAP_FIXED) && ((addr) + (len) > DEFAULT_MAP_WINDOW)) ? TASK_SIZE : \
> - DEFAULT_MAP_WINDOW)
> +#define arch_get_mmap_end(addr, len, flags) \
> +({ \
> + unsigned long mmap_end; \
> + typeof(flags) _flags = (flags); \
> + typeof(addr) _addr = (addr); \
> + typeof(len) _len = (len); \
> + if (_flags & MAP_BELOW_HINT && _addr != 0 && ((_addr + _len) > BIT(VA_BITS - 1))) \
> + mmap_end = (_addr + _len); \
> + else \
> + mmap_end = (((_addr) > DEFAULT_MAP_WINDOW) || \
> + (((_flags) & MAP_FIXED) && ((_addr) + (_len) > DEFAULT_MAP_WINDOW))\
> + ? TASK_SIZE : DEFAULT_MAP_WINDOW) \
> + mmap_end; \
> +})
>
> #endif /* _ASM_POWERPC_TASK_SIZE_64_H */
>