Orange Pi5 kernel

^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   1) // SPDX-License-Identifier: GPL-2.0-or-later
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   2) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   3)  *  flexible mmap layout support
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   4)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   5)  * Copyright 2003-2004 Red Hat Inc., Durham, North Carolina.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   6)  * All Rights Reserved.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   7)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   8)  * Started by Ingo Molnar <mingo@elte.hu>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   9)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  10) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  11) #include <linux/personality.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  12) #include <linux/mm.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  13) #include <linux/random.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  14) #include <linux/sched/signal.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  15) #include <linux/sched/mm.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  16) #include <linux/elf-randomize.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  17) #include <linux/security.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  18) #include <linux/mman.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  19) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  20) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  21)  * Top of mmap area (just below the process stack).
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  22)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  23)  * Leave at least a ~128 MB hole.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  24)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  25) #define MIN_GAP (128*1024*1024)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  26) #define MAX_GAP (TASK_SIZE/6*5)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  27) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  28) static inline int mmap_is_legacy(struct rlimit *rlim_stack)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  29) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  30) 	if (current->personality & ADDR_COMPAT_LAYOUT)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  31) 		return 1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  32) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  33) 	if (rlim_stack->rlim_cur == RLIM_INFINITY)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  34) 		return 1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  35) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  36) 	return sysctl_legacy_va_layout;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  37) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  38) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  39) unsigned long arch_mmap_rnd(void)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  40) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  41) 	unsigned long shift, rnd;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  42) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  43) 	shift = mmap_rnd_bits;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  44) #ifdef CONFIG_COMPAT
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  45) 	if (is_32bit_task())
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  46) 		shift = mmap_rnd_compat_bits;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  47) #endif
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  48) 	rnd = get_random_long() % (1ul << shift);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  49) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  50) 	return rnd << PAGE_SHIFT;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  51) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  52) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  53) static inline unsigned long stack_maxrandom_size(void)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  54) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  55) 	if (!(current->flags & PF_RANDOMIZE))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  56) 		return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  57) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  58) 	/* 8MB for 32bit, 1GB for 64bit */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  59) 	if (is_32bit_task())
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  60) 		return (1<<23);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  61) 	else
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  62) 		return (1<<30);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  63) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  64) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  65) static inline unsigned long mmap_base(unsigned long rnd,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  66) 				      struct rlimit *rlim_stack)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  67) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  68) 	unsigned long gap = rlim_stack->rlim_cur;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  69) 	unsigned long pad = stack_maxrandom_size() + stack_guard_gap;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  70) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  71) 	/* Values close to RLIM_INFINITY can overflow. */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  72) 	if (gap + pad > gap)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  73) 		gap += pad;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  74) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  75) 	if (gap < MIN_GAP)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  76) 		gap = MIN_GAP;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  77) 	else if (gap > MAX_GAP)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  78) 		gap = MAX_GAP;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  79) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  80) 	return PAGE_ALIGN(DEFAULT_MAP_WINDOW - gap - rnd);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  81) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  82) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  83) #ifdef CONFIG_PPC_RADIX_MMU
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  84) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  85)  * Same function as generic code used only for radix, because we don't need to overload
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  86)  * the generic one. But we will have to duplicate, because hash select
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  87)  * HAVE_ARCH_UNMAPPED_AREA
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  88)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  89) static unsigned long
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  90) radix__arch_get_unmapped_area(struct file *filp, unsigned long addr,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  91) 			     unsigned long len, unsigned long pgoff,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  92) 			     unsigned long flags)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  93) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  94) 	struct mm_struct *mm = current->mm;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  95) 	struct vm_area_struct *vma;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  96) 	int fixed = (flags & MAP_FIXED);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  97) 	unsigned long high_limit;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  98) 	struct vm_unmapped_area_info info;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  99) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 100) 	high_limit = DEFAULT_MAP_WINDOW;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 101) 	if (addr >= high_limit || (fixed && (addr + len > high_limit)))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 102) 		high_limit = TASK_SIZE;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 103) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 104) 	if (len > high_limit)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 105) 		return -ENOMEM;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 106) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 107) 	if (fixed) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 108) 		if (addr > high_limit - len)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 109) 			return -ENOMEM;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 110) 		return addr;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 111) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 112) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 113) 	if (addr) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 114) 		addr = PAGE_ALIGN(addr);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 115) 		vma = find_vma(mm, addr);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 116) 		if (high_limit - len >= addr && addr >= mmap_min_addr &&
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 117) 		    (!vma || addr + len <= vm_start_gap(vma)))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 118) 			return addr;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 119) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 120) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 121) 	info.flags = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 122) 	info.length = len;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 123) 	info.low_limit = mm->mmap_base;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 124) 	info.high_limit = high_limit;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 125) 	info.align_mask = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 126) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 127) 	return vm_unmapped_area(&info);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 128) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 129) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 130) static unsigned long
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 131) radix__arch_get_unmapped_area_topdown(struct file *filp,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 132) 				     const unsigned long addr0,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 133) 				     const unsigned long len,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 134) 				     const unsigned long pgoff,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 135) 				     const unsigned long flags)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 136) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 137) 	struct vm_area_struct *vma;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 138) 	struct mm_struct *mm = current->mm;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 139) 	unsigned long addr = addr0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 140) 	int fixed = (flags & MAP_FIXED);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 141) 	unsigned long high_limit;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 142) 	struct vm_unmapped_area_info info;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 143) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 144) 	high_limit = DEFAULT_MAP_WINDOW;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 145) 	if (addr >= high_limit || (fixed && (addr + len > high_limit)))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 146) 		high_limit = TASK_SIZE;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 147) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 148) 	if (len > high_limit)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 149) 		return -ENOMEM;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 150) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 151) 	if (fixed) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 152) 		if (addr > high_limit - len)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 153) 			return -ENOMEM;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 154) 		return addr;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 155) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 156) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 157) 	if (addr) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 158) 		addr = PAGE_ALIGN(addr);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 159) 		vma = find_vma(mm, addr);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 160) 		if (high_limit - len >= addr && addr >= mmap_min_addr &&
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 161) 		    (!vma || addr + len <= vm_start_gap(vma)))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 162) 			return addr;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 163) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 164) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 165) 	info.flags = VM_UNMAPPED_AREA_TOPDOWN;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 166) 	info.length = len;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 167) 	info.low_limit = max(PAGE_SIZE, mmap_min_addr);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 168) 	info.high_limit = mm->mmap_base + (high_limit - DEFAULT_MAP_WINDOW);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 169) 	info.align_mask = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 170) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 171) 	addr = vm_unmapped_area(&info);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 172) 	if (!(addr & ~PAGE_MASK))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 173) 		return addr;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 174) 	VM_BUG_ON(addr != -ENOMEM);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 175) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 176) 	/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 177) 	 * A failed mmap() very likely causes application failure,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 178) 	 * so fall back to the bottom-up function here. This scenario
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 179) 	 * can happen with large stack limits and large mmap()
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 180) 	 * allocations.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 181) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 182) 	return radix__arch_get_unmapped_area(filp, addr0, len, pgoff, flags);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 183) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 184) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 185) static void radix__arch_pick_mmap_layout(struct mm_struct *mm,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 186) 					unsigned long random_factor,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 187) 					struct rlimit *rlim_stack)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 188) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 189) 	if (mmap_is_legacy(rlim_stack)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 190) 		mm->mmap_base = TASK_UNMAPPED_BASE;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 191) 		mm->get_unmapped_area = radix__arch_get_unmapped_area;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 192) 	} else {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 193) 		mm->mmap_base = mmap_base(random_factor, rlim_stack);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 194) 		mm->get_unmapped_area = radix__arch_get_unmapped_area_topdown;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 195) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 196) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 197) #else
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 198) /* dummy */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 199) extern void radix__arch_pick_mmap_layout(struct mm_struct *mm,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 200) 					unsigned long random_factor,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 201) 					struct rlimit *rlim_stack);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 202) #endif
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 203) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 204)  * This function, called very early during the creation of a new
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 205)  * process VM image, sets up which VM layout function to use:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 206)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 207) void arch_pick_mmap_layout(struct mm_struct *mm, struct rlimit *rlim_stack)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 208) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 209) 	unsigned long random_factor = 0UL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 210) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 211) 	if (current->flags & PF_RANDOMIZE)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 212) 		random_factor = arch_mmap_rnd();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 213) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 214) 	if (radix_enabled())
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 215) 		return radix__arch_pick_mmap_layout(mm, random_factor,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 216) 						    rlim_stack);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 217) 	/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 218) 	 * Fall back to the standard layout if the personality
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 219) 	 * bit is set, or if the expected stack growth is unlimited:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 220) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 221) 	if (mmap_is_legacy(rlim_stack)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 222) 		mm->mmap_base = TASK_UNMAPPED_BASE;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 223) 		mm->get_unmapped_area = arch_get_unmapped_area;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 224) 	} else {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 225) 		mm->mmap_base = mmap_base(random_factor, rlim_stack);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 226) 		mm->get_unmapped_area = arch_get_unmapped_area_topdown;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 227) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 228) }