share_pool: Reserve the va space for share_pool

ascend inclusion
category: Feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I4NDAW
CVE: NA

-------------------

Change the mmap_base in mm_struct and check the limit in
get_unmapped_area.
Signed-off-by: NWang Wensheng <wangwensheng4@huawei.com>
Signed-off-by: NPeng Wu <wupeng58@huawei.com>
Reviewed-by: Kefeng Wang<wangkefeng.wang@huawei.com>
Reviewed-by: NWeilong Chen <chenweilong@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

include/linux/share_pool.h

@@ -262,6 +262,16 @@ static inline bool sp_is_enabled(void)
 	return static_branch_likely(&share_pool_enabled_key);
 }
 
+static inline void sp_area_work_around(struct vm_unmapped_area_info *info,
+				       unsigned long flags)
+{
+	/* the MAP_DVPP couldn't work with MAP_SHARE_POOL. In addition, the
+	 * address ranges corresponding to the two flags must not overlap.
+	 */
+	if (sp_is_enabled() && !(flags & MAP_DVPP))
+		info->high_limit = min(info->high_limit, MMAP_SHARE_POOL_START);
+}
+
 #else /* CONFIG_ASCEND_SHARE_POOL */
 
 static inline int mg_sp_group_add_task(int pid, unsigned long prot, int spg_id)
@@ -442,7 +452,7 @@ static inline bool sp_is_enabled(void)
 	return false;
 }
 
-static inline void sp_area_work_around(struct vm_unmapped_area_info *info)
+static inline void sp_area_work_around(struct vm_unmapped_area_info *info, unsigned long flags)
 {
 }
 

mm/mmap.c

@@ -48,6 +48,7 @@
 #include <linux/oom.h>
 #include <linux/sched/mm.h>
 #include <linux/swapops.h>
+#include <linux/share_pool.h>
 
 #include <linux/uaccess.h>
 #include <asm/cacheflush.h>
@@ -2450,6 +2451,8 @@ arch_get_unmapped_area(struct file *filp, unsigned long addr,
 	if (enable_mmap_dvpp)
 		dvpp_mmap_get_area(&info, flags);
 
+	sp_area_work_around(&info, flags);
+
 	return vm_unmapped_area(&info);
 }
 #endif
@@ -2500,6 +2503,8 @@ arch_get_unmapped_area_topdown(struct file *filp, unsigned long addr,
 	if (enable_mmap_dvpp)
 		dvpp_mmap_get_area(&info, flags);
 
+	sp_area_work_around(&info, flags);
+
 	addr = vm_unmapped_area(&info);
 
 	/*
@@ -2517,6 +2522,8 @@ arch_get_unmapped_area_topdown(struct file *filp, unsigned long addr,
 		if (enable_mmap_dvpp)
 			dvpp_mmap_get_area(&info, flags);
 
+		sp_area_work_around(&info, flags);
+
 		addr = vm_unmapped_area(&info);
 	}
 

mm/util.c

@@ -23,6 +23,7 @@
 #include <linux/processor.h>
 #include <linux/sizes.h>
 #include <linux/compat.h>
+#include <linux/share_pool.h>
 
 #include <linux/uaccess.h>
 #include <linux/oom.h>
@@ -392,6 +393,9 @@ static unsigned long mmap_base(unsigned long rnd, struct rlimit *rlim_stack)
 	else if (gap > MAX_GAP)
 		gap = MAX_GAP;
 
+	if (sp_is_enabled())
+		return ALIGN_DOWN(MMAP_SHARE_POOL_START - rnd, PAGE_SIZE);
+
 	return PAGE_ALIGN(STACK_TOP - gap - rnd);
 }