/*
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* This program is free software and is provided to you under the terms of the
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* GNU General Public License version 2 as published by the Free Software
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* Foundation, and any use by you of this program is subject to the terms
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* of such GNU licence.
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*
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* A copy of the licence is included with the program, and can also be obtained
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* from Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
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* Boston, MA 02110-1301, USA.
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*/
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#include "linux/mman.h"
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#include <mali_kbase.h>
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/* mali_kbase_mmap.c
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*
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* This file contains Linux specific implementation of
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* kbase_context_get_unmapped_area() interface.
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*/
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/**
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* align_and_check() - Align the specified pointer to the provided alignment and
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* check that it is still in range.
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* @gap_end: Highest possible start address for allocation (end of gap in
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* address space)
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* @gap_start: Start address of current memory area / gap in address space
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* @info: vm_unmapped_area_info structure passed to caller, containing
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* alignment, length and limits for the allocation
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* @is_shader_code: True if the allocation is for shader code (which has
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* additional alignment requirements)
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* @is_same_4gb_page: True if the allocation needs to reside completely within
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* a 4GB chunk
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*
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* Return: true if gap_end is now aligned correctly and is still in range,
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* false otherwise
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*/
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static bool align_and_check(unsigned long *gap_end, unsigned long gap_start,
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struct vm_unmapped_area_info *info, bool is_shader_code,
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bool is_same_4gb_page)
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{
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/* Compute highest gap address at the desired alignment */
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(*gap_end) -= info->length;
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(*gap_end) -= (*gap_end - info->align_offset) & info->align_mask;
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if (is_shader_code) {
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/* Check for 4GB boundary */
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if (0 == (*gap_end & BASE_MEM_MASK_4GB))
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(*gap_end) -= (info->align_offset ? info->align_offset :
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info->length);
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if (0 == ((*gap_end + info->length) & BASE_MEM_MASK_4GB))
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(*gap_end) -= (info->align_offset ? info->align_offset :
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info->length);
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if (!(*gap_end & BASE_MEM_MASK_4GB) || !((*gap_end +
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info->length) & BASE_MEM_MASK_4GB))
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return false;
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} else if (is_same_4gb_page) {
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unsigned long start = *gap_end;
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unsigned long end = *gap_end + info->length;
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unsigned long mask = ~((unsigned long)U32_MAX);
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/* Check if 4GB boundary is straddled */
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if ((start & mask) != ((end - 1) & mask)) {
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unsigned long offset = end - (end & mask);
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/* This is to ensure that alignment doesn't get
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* disturbed in an attempt to prevent straddling at
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* 4GB boundary. The GPU VA is aligned to 2MB when the
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* allocation size is > 2MB and there is enough CPU &
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* GPU virtual space.
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*/
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unsigned long rounded_offset =
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ALIGN(offset, info->align_mask + 1);
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start -= rounded_offset;
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end -= rounded_offset;
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*gap_end = start;
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/* The preceding 4GB boundary shall not get straddled,
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* even after accounting for the alignment, as the
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* size of allocation is limited to 4GB and the initial
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* start location was already aligned.
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*/
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WARN_ON((start & mask) != ((end - 1) & mask));
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}
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}
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if ((*gap_end < info->low_limit) || (*gap_end < gap_start))
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return false;
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return true;
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}
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/**
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* kbase_unmapped_area_topdown() - allocates new areas top-down from
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* below the stack limit.
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* @info: Information about the memory area to allocate.
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* @is_shader_code: Boolean which denotes whether the allocated area is
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* intended for the use by shader core in which case a
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* special alignment requirements apply.
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* @is_same_4gb_page: Boolean which indicates whether the allocated area needs
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* to reside completely within a 4GB chunk.
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*
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* The unmapped_area_topdown() function in the Linux kernel is not exported
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* using EXPORT_SYMBOL_GPL macro. To allow us to call this function from a
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* module and also make use of the fact that some of the requirements for
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* the unmapped area are known in advance, we implemented an extended version
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* of this function and prefixed it with 'kbase_'.
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*
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* The difference in the call parameter list comes from the fact that
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* kbase_unmapped_area_topdown() is called with additional parameters which
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* are provided to indicate whether the allocation is for a shader core memory,
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* which has additional alignment requirements, and whether the allocation can
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* straddle a 4GB boundary.
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*
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* The modification of the original Linux function lies in how the computation
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* of the highest gap address at the desired alignment is performed once the
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* gap with desirable properties is found. For this purpose a special function
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* is introduced (@ref align_and_check()) which beside computing the gap end
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* at the desired alignment also performs additional alignment checks for the
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* case when the memory is executable shader core memory, for which it is
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* ensured that the gap does not end on a 4GB boundary, and for the case when
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* memory needs to be confined within a 4GB chunk.
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*
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* Return: address of the found gap end (high limit) if area is found;
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* -ENOMEM if search is unsuccessful
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*/
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static unsigned long kbase_unmapped_area_topdown(struct vm_unmapped_area_info
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*info, bool is_shader_code, bool is_same_4gb_page)
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{
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struct mm_struct *mm = current->mm;
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struct vm_area_struct *vma;
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unsigned long length, low_limit, high_limit, gap_start, gap_end;
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/* Adjust search length to account for worst case alignment overhead */
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length = info->length + info->align_mask;
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if (length < info->length)
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return -ENOMEM;
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/*
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* Adjust search limits by the desired length.
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* See implementation comment at top of unmapped_area().
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*/
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gap_end = info->high_limit;
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if (gap_end < length)
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return -ENOMEM;
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high_limit = gap_end - length;
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if (info->low_limit > high_limit)
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return -ENOMEM;
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low_limit = info->low_limit + length;
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/* Check highest gap, which does not precede any rbtree node */
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gap_start = mm->highest_vm_end;
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if (gap_start <= high_limit) {
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if (align_and_check(&gap_end, gap_start, info,
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is_shader_code, is_same_4gb_page))
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return gap_end;
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}
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/* Check if rbtree root looks promising */
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if (RB_EMPTY_ROOT(&mm->mm_rb))
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return -ENOMEM;
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vma = rb_entry(mm->mm_rb.rb_node, struct vm_area_struct, vm_rb);
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if (vma->rb_subtree_gap < length)
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return -ENOMEM;
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while (true) {
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/* Visit right subtree if it looks promising */
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gap_start = vma->vm_prev ? vma->vm_prev->vm_end : 0;
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if (gap_start <= high_limit && vma->vm_rb.rb_right) {
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struct vm_area_struct *right =
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rb_entry(vma->vm_rb.rb_right,
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struct vm_area_struct, vm_rb);
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if (right->rb_subtree_gap >= length) {
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vma = right;
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continue;
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}
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}
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check_current:
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/* Check if current node has a suitable gap */
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gap_end = vma->vm_start;
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if (gap_end < low_limit)
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return -ENOMEM;
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if (gap_start <= high_limit && gap_end - gap_start >= length) {
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/* We found a suitable gap. Clip it with the original
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* high_limit.
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*/
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if (gap_end > info->high_limit)
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gap_end = info->high_limit;
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if (align_and_check(&gap_end, gap_start, info,
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is_shader_code, is_same_4gb_page))
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return gap_end;
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}
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/* Visit left subtree if it looks promising */
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if (vma->vm_rb.rb_left) {
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struct vm_area_struct *left =
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rb_entry(vma->vm_rb.rb_left,
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struct vm_area_struct, vm_rb);
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if (left->rb_subtree_gap >= length) {
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vma = left;
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continue;
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}
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}
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/* Go back up the rbtree to find next candidate node */
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while (true) {
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struct rb_node *prev = &vma->vm_rb;
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if (!rb_parent(prev))
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return -ENOMEM;
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vma = rb_entry(rb_parent(prev),
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struct vm_area_struct, vm_rb);
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if (prev == vma->vm_rb.rb_right) {
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gap_start = vma->vm_prev ?
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vma->vm_prev->vm_end : 0;
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goto check_current;
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}
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}
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}
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return -ENOMEM;
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}
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/* This function is based on Linux kernel's arch_get_unmapped_area, but
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* simplified slightly. Modifications come from the fact that some values
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* about the memory area are known in advance.
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*/
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unsigned long kbase_context_get_unmapped_area(struct kbase_context *const kctx,
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const unsigned long addr, const unsigned long len,
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const unsigned long pgoff, const unsigned long flags)
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{
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struct mm_struct *mm = current->mm;
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struct vm_unmapped_area_info info;
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unsigned long align_offset = 0;
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unsigned long align_mask = 0;
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unsigned long high_limit = mm->mmap_base;
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unsigned long low_limit = PAGE_SIZE;
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int cpu_va_bits = BITS_PER_LONG;
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int gpu_pc_bits =
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kctx->kbdev->gpu_props.props.core_props.log2_program_counter_size;
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bool is_shader_code = false;
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bool is_same_4gb_page = false;
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unsigned long ret;
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/* the 'nolock' form is used here:
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* - the base_pfn of the SAME_VA zone does not change
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* - in normal use, va_size_pages is constant once the first allocation
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* begins
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*
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* However, in abnormal use this function could be processing whilst
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* another new zone is being setup in a different thread (e.g. to
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* borrow part of the SAME_VA zone). In the worst case, this path may
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* witness a higher SAME_VA end_pfn than the code setting up the new
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* zone.
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*
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* This is safe because once we reach the main allocation functions,
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* we'll see the updated SAME_VA end_pfn and will determine that there
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* is no free region at the address found originally by too large a
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* same_va_end_addr here, and will fail the allocation gracefully.
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*/
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struct kbase_reg_zone *zone =
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kbase_ctx_reg_zone_get_nolock(kctx, KBASE_REG_ZONE_SAME_VA);
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u64 same_va_end_addr = kbase_reg_zone_end_pfn(zone) << PAGE_SHIFT;
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/* err on fixed address */
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if ((flags & MAP_FIXED) || addr)
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return -EINVAL;
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#if IS_ENABLED(CONFIG_64BIT)
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/* too big? */
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if (len > TASK_SIZE - SZ_2M)
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return -ENOMEM;
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if (!kbase_ctx_flag(kctx, KCTX_COMPAT)) {
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high_limit =
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min_t(unsigned long, mm->mmap_base, same_va_end_addr);
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/* If there's enough (> 33 bits) of GPU VA space, align
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* to 2MB boundaries.
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*/
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if (kctx->kbdev->gpu_props.mmu.va_bits > 33) {
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if (len >= SZ_2M) {
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align_offset = SZ_2M;
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align_mask = SZ_2M - 1;
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}
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}
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low_limit = SZ_2M;
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} else {
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cpu_va_bits = 32;
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}
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#endif /* CONFIG_64BIT */
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if ((PFN_DOWN(BASE_MEM_COOKIE_BASE) <= pgoff) &&
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(PFN_DOWN(BASE_MEM_FIRST_FREE_ADDRESS) > pgoff)) {
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int cookie = pgoff - PFN_DOWN(BASE_MEM_COOKIE_BASE);
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struct kbase_va_region *reg;
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/* Need to hold gpu vm lock when using reg */
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kbase_gpu_vm_lock(kctx);
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reg = kctx->pending_regions[cookie];
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if (!reg) {
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kbase_gpu_vm_unlock(kctx);
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return -EINVAL;
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}
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if (!(reg->flags & KBASE_REG_GPU_NX)) {
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if (cpu_va_bits > gpu_pc_bits) {
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align_offset = 1ULL << gpu_pc_bits;
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align_mask = align_offset - 1;
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is_shader_code = true;
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}
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#if !MALI_USE_CSF
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} else if (reg->flags & KBASE_REG_TILER_ALIGN_TOP) {
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unsigned long extension_bytes =
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(unsigned long)(reg->extension
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<< PAGE_SHIFT);
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/* kbase_check_alloc_sizes() already satisfies
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* these checks, but they're here to avoid
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* maintenance hazards due to the assumptions
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* involved
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*/
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WARN_ON(reg->extension >
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(ULONG_MAX >> PAGE_SHIFT));
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WARN_ON(reg->initial_commit > (ULONG_MAX >> PAGE_SHIFT));
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WARN_ON(!is_power_of_2(extension_bytes));
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align_mask = extension_bytes - 1;
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align_offset =
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extension_bytes -
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(reg->initial_commit << PAGE_SHIFT);
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#endif /* !MALI_USE_CSF */
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} else if (reg->flags & KBASE_REG_GPU_VA_SAME_4GB_PAGE) {
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is_same_4gb_page = true;
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}
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kbase_gpu_vm_unlock(kctx);
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#ifndef CONFIG_64BIT
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} else {
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return current->mm->get_unmapped_area(
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kctx->filp, addr, len, pgoff, flags);
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#endif
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}
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info.flags = 0;
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info.length = len;
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info.low_limit = low_limit;
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info.high_limit = high_limit;
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info.align_offset = align_offset;
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info.align_mask = align_mask;
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ret = kbase_unmapped_area_topdown(&info, is_shader_code,
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is_same_4gb_page);
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if (IS_ERR_VALUE(ret) && high_limit == mm->mmap_base &&
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high_limit < same_va_end_addr) {
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/* Retry above mmap_base */
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info.low_limit = mm->mmap_base;
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info.high_limit = min_t(u64, TASK_SIZE, same_va_end_addr);
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ret = kbase_unmapped_area_topdown(&info, is_shader_code,
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is_same_4gb_page);
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}
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return ret;
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}
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