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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: Jiantao Shan <shanjiantao@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
This commit is contained in:
Huacai Chen 2023-09-06 22:53:09 +08:00
parent 303be4b335
commit ad3ff10561
2 changed files with 6 additions and 8 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
arch/loongarch/mm/cache.c
View File

@ -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] = {

13
arch/loongarch/mm/mmap.c
View File

@ -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))
#define COLOUR_ALIGN(addr, pgoff) \
((((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) {