Commit ad3ff105 authored by Huacai Chen's avatar Huacai Chen
Browse files

LoongArch: Remove shm_align_mask and use SHMLBA instead 



Both shm_align_mask and SHMLBA want to avoid cache alias. But they are
inconsistent: shm_align_mask is (PAGE_SIZE - 1) while SHMLBA is SZ_64K,
but PAGE_SIZE is not always equal to SZ_64K.

This may cause problems when shmat() twice. Fix this problem by removing
shm_align_mask and using SHMLBA (strictly SHMLBA - 1) instead.

Reported-by: default avatarJiantao Shan <shanjiantao@loongson.cn>
Signed-off-by: default avatarHuacai Chen <chenhuacai@loongson.cn>
parent 303be4b3

arch/loongarch/mm/cache.c

+0 −1
Original line number Diff line number Diff line
@@ -156,7 +156,6 @@ void cpu_cache_init(void) 


	current_cpu_data.cache_leaves_present = leaf;

	current_cpu_data.options |= LOONGARCH_CPU_PREFETCH;

	shm_align_mask = PAGE_SIZE - 1;

}



static const pgprot_t protection_map[16] = {

arch/loongarch/mm/mmap.c

+6 −7
Original line number Diff line number Diff line
@@ -8,12 +8,11 @@ 
#include <linux/mm.h>

#include <linux/mman.h>



unsigned long shm_align_mask = PAGE_SIZE - 1;	/* Sane caches */

EXPORT_SYMBOL(shm_align_mask);

#define SHM_ALIGN_MASK	(SHMLBA - 1)



#define COLOUR_ALIGN(addr, pgoff)			\

	((((addr) + shm_align_mask) & ~shm_align_mask) +	\

	 (((pgoff) << PAGE_SHIFT) & shm_align_mask))

	((((addr) + SHM_ALIGN_MASK) & ~SHM_ALIGN_MASK)	\

	 + (((pgoff) << PAGE_SHIFT) & SHM_ALIGN_MASK))



enum mmap_allocation_direction {UP, DOWN};
@@ -40,7 +39,7 @@ static unsigned long arch_get_unmapped_area_common(struct file *filp, 
		 * cache aliasing constraints.

		 */

		if ((flags & MAP_SHARED) &&

		    ((addr - (pgoff << PAGE_SHIFT)) & shm_align_mask))

		    ((addr - (pgoff << PAGE_SHIFT)) & SHM_ALIGN_MASK))

			return -EINVAL;

		return addr;

	}
@@ -63,7 +62,7 @@ static unsigned long arch_get_unmapped_area_common(struct file *filp, 
	}



	info.length = len;

	info.align_mask = do_color_align ? (PAGE_MASK & shm_align_mask) : 0;

	info.align_mask = do_color_align ? (PAGE_MASK & SHM_ALIGN_MASK) : 0;

	info.align_offset = pgoff << PAGE_SHIFT;



	if (dir == DOWN) {