| Message ID | 20230417125630.1146906-3-usama.anjum@collabora.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | Implement IOCTL to get and optionally clear info about PTEs | expand |
Hi Muhammad,
kernel test robot noticed the following build warnings:
[auto build test WARNING on akpm-mm/mm-everything]
[cannot apply to linus/master v6.3-rc7]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]
url: https://github.com/intel-lab-lkp/linux/commits/Muhammad-Usama-Anjum/userfaultfd-UFFD_FEATURE_WP_ASYNC/20230417-210005
base: https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-everything
patch link: https://lore.kernel.org/r/20230417125630.1146906-3-usama.anjum%40collabora.com
patch subject: [PATCH v13 2/5] fs/proc/task_mmu: Implement IOCTL to get and optionally clear info about PTEs
config: i386-randconfig-a003-20230417 (https://download.01.org/0day-ci/archive/20230417/202304172319.CjlksY4s-lkp@intel.com/config)
compiler: gcc-11 (Debian 11.3.0-8) 11.3.0
reproduce (this is a W=1 build):
# https://github.com/intel-lab-lkp/linux/commit/2e7e6f5bd3b9c28493f9871282fe8f14e2263962
git remote add linux-review https://github.com/intel-lab-lkp/linux
git fetch --no-tags linux-review Muhammad-Usama-Anjum/userfaultfd-UFFD_FEATURE_WP_ASYNC/20230417-210005
git checkout 2e7e6f5bd3b9c28493f9871282fe8f14e2263962
# save the config file
mkdir build_dir && cp config build_dir/.config
make W=1 O=build_dir ARCH=i386 olddefconfig
make W=1 O=build_dir ARCH=i386 SHELL=/bin/bash fs/proc/
If you fix the issue, kindly add following tag where applicable
| Reported-by: kernel test robot <lkp@intel.com>
| Link: https://lore.kernel.org/oe-kbuild-all/202304172319.CjlksY4s-lkp@intel.com/
All warnings (new ones prefixed by >>):
fs/proc/task_mmu.c: In function 'pagemap_scan_pte_hole':
fs/proc/task_mmu.c:2059:14: error: invalid use of undefined type 'struct pagemap_scan_private'
2059 | if (p->max_pages && p->found_pages + n_pages > p->max_pages)
| ^~
fs/proc/task_mmu.c:2059:30: error: invalid use of undefined type 'struct pagemap_scan_private'
2059 | if (p->max_pages && p->found_pages + n_pages > p->max_pages)
| ^~
fs/proc/task_mmu.c:2059:57: error: invalid use of undefined type 'struct pagemap_scan_private'
2059 | if (p->max_pages && p->found_pages + n_pages > p->max_pages)
| ^~
fs/proc/task_mmu.c:2060:28: error: invalid use of undefined type 'struct pagemap_scan_private'
2060 | n_pages = p->max_pages - p->found_pages;
| ^~
fs/proc/task_mmu.c:2060:43: error: invalid use of undefined type 'struct pagemap_scan_private'
2060 | n_pages = p->max_pages - p->found_pages;
| ^~
fs/proc/task_mmu.c:2062:15: error: implicit declaration of function 'pagemap_scan_output' [-Werror=implicit-function-declaration]
2062 | ret = pagemap_scan_output(false, vma->vm_file, false, false, p, addr,
| ^~~~~~~~~~~~~~~~~~~
fs/proc/task_mmu.c: At top level:
fs/proc/task_mmu.c:2068:22: error: 'pagemap_scan_test_walk' undeclared here (not in a function); did you mean 'pagemap_scan_pte_hole'?
2068 | .test_walk = pagemap_scan_test_walk,
| ^~~~~~~~~~~~~~~~~~~~~~
| pagemap_scan_pte_hole
fs/proc/task_mmu.c:2069:22: error: 'pagemap_scan_pmd_entry' undeclared here (not in a function); did you mean 'pagemap_scan_pte_hole'?
2069 | .pmd_entry = pagemap_scan_pmd_entry,
| ^~~~~~~~~~~~~~~~~~~~~~
| pagemap_scan_pte_hole
fs/proc/task_mmu.c: In function 'pagemap_scan_args_valid':
fs/proc/task_mmu.c:2080:27: error: 'PM_SCAN_OPS' undeclared (first use in this function); did you mean 'PM_SCAN_OP_WP'?
2080 | if (arg->flags & ~PM_SCAN_OPS)
| ^~~~~~~~~~~
| PM_SCAN_OP_WP
fs/proc/task_mmu.c:2080:27: note: each undeclared identifier is reported only once for each function it appears in
fs/proc/task_mmu.c:2085:35: error: 'PM_SCAN_BITS_ALL' undeclared (first use in this function); did you mean 'CPU_BITS_ALL'?
2085 | arg->return_mask) & ~PM_SCAN_BITS_ALL)
| ^~~~~~~~~~~~~~~~
| CPU_BITS_ALL
fs/proc/task_mmu.c:2106:14: error: implicit declaration of function 'PM_SCAN_DO_UFFD_WP'; did you mean 'PM_SCAN_OP_WP'? [-Werror=implicit-function-declaration]
2106 | if (!PM_SCAN_DO_UFFD_WP(arg))
| ^~~~~~~~~~~~~~~~~~
| PM_SCAN_OP_WP
fs/proc/task_mmu.c: In function 'do_pagemap_scan':
fs/proc/task_mmu.c:2123:37: error: storage size of 'p' isn't known
2123 | struct pagemap_scan_private p;
| ^
fs/proc/task_mmu.c:2148:21: error: 'PAGEMAP_WALK_SIZE' undeclared (first use in this function); did you mean 'PAGE_TABLE_SIZE'?
2148 | p.vec_len = PAGEMAP_WALK_SIZE >> PAGE_SHIFT;
| ^~~~~~~~~~~~~~~~~
| PAGE_TABLE_SIZE
In file included from include/linux/kernel.h:27,
from arch/x86/include/asm/percpu.h:27,
from arch/x86/include/asm/preempt.h:6,
from include/linux/preempt.h:78,
from include/linux/spinlock.h:56,
from include/linux/mmzone.h:8,
from include/linux/gfp.h:7,
from include/linux/mm.h:7,
from include/linux/pagewalk.h:5,
from fs/proc/task_mmu.c:2:
include/linux/minmax.h:36:9: error: first argument to '__builtin_choose_expr' not a constant
36 | __builtin_choose_expr(__safe_cmp(x, y), \
| ^~~~~~~~~~~~~~~~~~~~~
include/linux/minmax.h:67:25: note: in expansion of macro '__careful_cmp'
67 | #define min(x, y) __careful_cmp(x, y, <)
| ^~~~~~~~~~~~~
fs/proc/task_mmu.c:2173:29: note: in expansion of macro 'min'
2173 | p.vec_len = min(p.vec_len, empty_slots);
| ^~~
fs/proc/task_mmu.c:2175:63: error: 'PAGEMAP_WALK_MASK' undeclared (first use in this function)
2175 | walk_end = (walk_start + PAGEMAP_WALK_SIZE) & PAGEMAP_WALK_MASK;
| ^~~~~~~~~~~~~~~~~
fs/proc/task_mmu.c:2186:53: error: 'PM_SCAN_FOUND_MAX_PAGES' undeclared (first use in this function)
2186 | if (ret && ret != -ENOSPC && ret != PM_SCAN_FOUND_MAX_PAGES)
| ^~~~~~~~~~~~~~~~~~~~~~~
>> fs/proc/task_mmu.c:2123:37: warning: unused variable 'p' [-Wunused-variable]
2123 | struct pagemap_scan_private p;
| ^
fs/proc/task_mmu.c: At top level:
fs/proc/task_mmu.c:2240:27: error: 'pagemap_read' undeclared here (not in a function); did you mean 'filemap_read'?
2240 | .read = pagemap_read,
| ^~~~~~~~~~~~
| filemap_read
fs/proc/task_mmu.c:2241:27: error: 'pagemap_open' undeclared here (not in a function); did you mean 'pid_maps_open'?
2241 | .open = pagemap_open,
| ^~~~~~~~~~~~
| pid_maps_open
fs/proc/task_mmu.c:2242:27: error: 'pagemap_release' undeclared here (not in a function); did you mean 'proc_map_release'?
2242 | .release = pagemap_release,
| ^~~~~~~~~~~~~~~
| proc_map_release
fs/proc/task_mmu.c:2246:2: error: #endif without #if
2246 | #endif /* CONFIG_PROC_PAGE_MONITOR */
| ^~~~~
cc1: some warnings being treated as errors
vim +/p +2123 fs/proc/task_mmu.c
2115
2116 static long do_pagemap_scan(struct mm_struct *mm,
2117 struct pm_scan_arg __user *uarg)
2118 {
2119 unsigned long start, end, walk_start, walk_end;
2120 unsigned long empty_slots, vec_index = 0;
2121 struct mmu_notifier_range range;
2122 struct page_region __user *vec;
> 2123 struct pagemap_scan_private p;
2124 struct pm_scan_arg arg;
2125 int ret = 0;
2126
2127 if (copy_from_user(&arg, uarg, sizeof(arg)))
2128 return -EFAULT;
2129
2130 start = untagged_addr((unsigned long)arg.start);
2131 vec = (struct page_region *)untagged_addr((unsigned long)arg.vec);
2132
2133 ret = pagemap_scan_args_valid(&arg, start, vec);
2134 if (ret)
2135 return ret;
2136
2137 end = start + arg.len;
2138 p.max_pages = arg.max_pages;
2139 p.found_pages = 0;
2140 p.flags = arg.flags;
2141 p.required_mask = arg.required_mask;
2142 p.anyof_mask = arg.anyof_mask;
2143 p.excluded_mask = arg.excluded_mask;
2144 p.return_mask = arg.return_mask;
2145 p.cur.len = 0;
2146 p.cur.start = 0;
2147 p.vec = NULL;
2148 p.vec_len = PAGEMAP_WALK_SIZE >> PAGE_SHIFT;
2149
2150 /*
2151 * Allocate smaller buffer to get output from inside the page walk
2152 * functions and walk page range in PAGEMAP_WALK_SIZE size chunks. As
2153 * we want to return output to user in compact form where no two
2154 * consecutive regions should be continuous and have the same flags.
2155 * So store the latest element in p.cur between different walks and
2156 * store the p.cur at the end of the walk to the user buffer.
2157 */
2158 p.vec = kmalloc_array(p.vec_len, sizeof(*p.vec), GFP_KERNEL);
2159 if (!p.vec)
2160 return -ENOMEM;
2161
2162 if (p.flags & PM_SCAN_OP_WP) {
2163 mmu_notifier_range_init(&range, MMU_NOTIFY_PROTECTION_VMA, 0,
2164 vma->vm_mm, start, end);
2165 mmu_notifier_invalidate_range_start(&range);
2166 }
2167
2168 walk_start = walk_end = start;
2169 while (walk_end < end && !ret) {
2170 p.vec_index = 0;
2171
2172 empty_slots = arg.vec_len - vec_index;
2173 p.vec_len = min(p.vec_len, empty_slots);
2174
2175 walk_end = (walk_start + PAGEMAP_WALK_SIZE) & PAGEMAP_WALK_MASK;
2176 if (walk_end > end)
2177 walk_end = end;
2178
2179 ret = mmap_read_lock_killable(mm);
2180 if (ret)
2181 goto free_data;
2182 ret = walk_page_range(mm, walk_start, walk_end,
2183 &pagemap_scan_ops, &p);
2184 mmap_read_unlock(mm);
2185
2186 if (ret && ret != -ENOSPC && ret != PM_SCAN_FOUND_MAX_PAGES)
2187 goto free_data;
2188
2189 walk_start = walk_end;
2190 if (p.vec_index) {
2191 if (copy_to_user(&vec[vec_index], p.vec,
2192 p.vec_index * sizeof(*p.vec))) {
2193 /*
2194 * Return error even though the OP succeeded
2195 */
2196 ret = -EFAULT;
2197 goto free_data;
2198 }
2199 vec_index += p.vec_index;
2200 }
2201 }
2202
2203 if (p.flags & PM_SCAN_OP_WP) {
2204 mmu_notifier_invalidate_range_end(&range);
2205 flush_tlb_mm_range(mm, start, end, PAGE_SHIFT, false);
2206 }
2207
2208 if (p.cur.len) {
2209 if (copy_to_user(&vec[vec_index], &p.cur, sizeof(*p.vec))) {
2210 ret = -EFAULT;
2211 goto free_data;
2212 }
2213 vec_index++;
2214 }
2215
2216 ret = vec_index;
2217
2218 free_data:
2219 kfree(p.vec);
2220 return ret;
2221 }
2222
Hi Muhammad,
kernel test robot noticed the following build errors:
[auto build test ERROR on akpm-mm/mm-everything]
[cannot apply to linus/master v6.3-rc7]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]
url: https://github.com/intel-lab-lkp/linux/commits/Muhammad-Usama-Anjum/userfaultfd-UFFD_FEATURE_WP_ASYNC/20230417-210005
base: https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-everything
patch link: https://lore.kernel.org/r/20230417125630.1146906-3-usama.anjum%40collabora.com
patch subject: [PATCH v13 2/5] fs/proc/task_mmu: Implement IOCTL to get and optionally clear info about PTEs
config: i386-randconfig-a003-20230417 (https://download.01.org/0day-ci/archive/20230418/202304180050.anuTGBfy-lkp@intel.com/config)
compiler: gcc-11 (Debian 11.3.0-8) 11.3.0
reproduce (this is a W=1 build):
# https://github.com/intel-lab-lkp/linux/commit/2e7e6f5bd3b9c28493f9871282fe8f14e2263962
git remote add linux-review https://github.com/intel-lab-lkp/linux
git fetch --no-tags linux-review Muhammad-Usama-Anjum/userfaultfd-UFFD_FEATURE_WP_ASYNC/20230417-210005
git checkout 2e7e6f5bd3b9c28493f9871282fe8f14e2263962
# save the config file
mkdir build_dir && cp config build_dir/.config
make W=1 O=build_dir ARCH=i386 olddefconfig
make W=1 O=build_dir ARCH=i386 SHELL=/bin/bash fs/
If you fix the issue, kindly add following tag where applicable
| Reported-by: kernel test robot <lkp@intel.com>
| Link: https://lore.kernel.org/oe-kbuild-all/202304180050.anuTGBfy-lkp@intel.com/
All errors (new ones prefixed by >>):
fs/proc/task_mmu.c: In function 'pagemap_scan_pte_hole':
>> fs/proc/task_mmu.c:2059:14: error: invalid use of undefined type 'struct pagemap_scan_private'
2059 | if (p->max_pages && p->found_pages + n_pages > p->max_pages)
| ^~
fs/proc/task_mmu.c:2059:30: error: invalid use of undefined type 'struct pagemap_scan_private'
2059 | if (p->max_pages && p->found_pages + n_pages > p->max_pages)
| ^~
fs/proc/task_mmu.c:2059:57: error: invalid use of undefined type 'struct pagemap_scan_private'
2059 | if (p->max_pages && p->found_pages + n_pages > p->max_pages)
| ^~
fs/proc/task_mmu.c:2060:28: error: invalid use of undefined type 'struct pagemap_scan_private'
2060 | n_pages = p->max_pages - p->found_pages;
| ^~
fs/proc/task_mmu.c:2060:43: error: invalid use of undefined type 'struct pagemap_scan_private'
2060 | n_pages = p->max_pages - p->found_pages;
| ^~
>> fs/proc/task_mmu.c:2062:15: error: implicit declaration of function 'pagemap_scan_output' [-Werror=implicit-function-declaration]
2062 | ret = pagemap_scan_output(false, vma->vm_file, false, false, p, addr,
| ^~~~~~~~~~~~~~~~~~~
fs/proc/task_mmu.c: At top level:
>> fs/proc/task_mmu.c:2068:22: error: 'pagemap_scan_test_walk' undeclared here (not in a function); did you mean 'pagemap_scan_pte_hole'?
2068 | .test_walk = pagemap_scan_test_walk,
| ^~~~~~~~~~~~~~~~~~~~~~
| pagemap_scan_pte_hole
>> fs/proc/task_mmu.c:2069:22: error: 'pagemap_scan_pmd_entry' undeclared here (not in a function); did you mean 'pagemap_scan_pte_hole'?
2069 | .pmd_entry = pagemap_scan_pmd_entry,
| ^~~~~~~~~~~~~~~~~~~~~~
| pagemap_scan_pte_hole
fs/proc/task_mmu.c: In function 'pagemap_scan_args_valid':
>> fs/proc/task_mmu.c:2080:27: error: 'PM_SCAN_OPS' undeclared (first use in this function); did you mean 'PM_SCAN_OP_WP'?
2080 | if (arg->flags & ~PM_SCAN_OPS)
| ^~~~~~~~~~~
| PM_SCAN_OP_WP
fs/proc/task_mmu.c:2080:27: note: each undeclared identifier is reported only once for each function it appears in
>> fs/proc/task_mmu.c:2085:35: error: 'PM_SCAN_BITS_ALL' undeclared (first use in this function); did you mean 'CPU_BITS_ALL'?
2085 | arg->return_mask) & ~PM_SCAN_BITS_ALL)
| ^~~~~~~~~~~~~~~~
| CPU_BITS_ALL
>> fs/proc/task_mmu.c:2106:14: error: implicit declaration of function 'PM_SCAN_DO_UFFD_WP'; did you mean 'PM_SCAN_OP_WP'? [-Werror=implicit-function-declaration]
2106 | if (!PM_SCAN_DO_UFFD_WP(arg))
| ^~~~~~~~~~~~~~~~~~
| PM_SCAN_OP_WP
fs/proc/task_mmu.c: In function 'do_pagemap_scan':
>> fs/proc/task_mmu.c:2123:37: error: storage size of 'p' isn't known
2123 | struct pagemap_scan_private p;
| ^
>> fs/proc/task_mmu.c:2148:21: error: 'PAGEMAP_WALK_SIZE' undeclared (first use in this function); did you mean 'PAGE_TABLE_SIZE'?
2148 | p.vec_len = PAGEMAP_WALK_SIZE >> PAGE_SHIFT;
| ^~~~~~~~~~~~~~~~~
| PAGE_TABLE_SIZE
In file included from include/linux/kernel.h:27,
from arch/x86/include/asm/percpu.h:27,
from arch/x86/include/asm/preempt.h:6,
from include/linux/preempt.h:78,
from include/linux/spinlock.h:56,
from include/linux/mmzone.h:8,
from include/linux/gfp.h:7,
from include/linux/mm.h:7,
from include/linux/pagewalk.h:5,
from fs/proc/task_mmu.c:2:
>> include/linux/minmax.h:36:9: error: first argument to '__builtin_choose_expr' not a constant
36 | __builtin_choose_expr(__safe_cmp(x, y), \
| ^~~~~~~~~~~~~~~~~~~~~
include/linux/minmax.h:67:25: note: in expansion of macro '__careful_cmp'
67 | #define min(x, y) __careful_cmp(x, y, <)
| ^~~~~~~~~~~~~
fs/proc/task_mmu.c:2173:29: note: in expansion of macro 'min'
2173 | p.vec_len = min(p.vec_len, empty_slots);
| ^~~
>> fs/proc/task_mmu.c:2175:63: error: 'PAGEMAP_WALK_MASK' undeclared (first use in this function)
2175 | walk_end = (walk_start + PAGEMAP_WALK_SIZE) & PAGEMAP_WALK_MASK;
| ^~~~~~~~~~~~~~~~~
>> fs/proc/task_mmu.c:2186:53: error: 'PM_SCAN_FOUND_MAX_PAGES' undeclared (first use in this function)
2186 | if (ret && ret != -ENOSPC && ret != PM_SCAN_FOUND_MAX_PAGES)
| ^~~~~~~~~~~~~~~~~~~~~~~
fs/proc/task_mmu.c:2123:37: warning: unused variable 'p' [-Wunused-variable]
2123 | struct pagemap_scan_private p;
| ^
fs/proc/task_mmu.c: At top level:
>> fs/proc/task_mmu.c:2240:27: error: 'pagemap_read' undeclared here (not in a function); did you mean 'filemap_read'?
2240 | .read = pagemap_read,
| ^~~~~~~~~~~~
| filemap_read
>> fs/proc/task_mmu.c:2241:27: error: 'pagemap_open' undeclared here (not in a function); did you mean 'pid_maps_open'?
2241 | .open = pagemap_open,
| ^~~~~~~~~~~~
| pid_maps_open
>> fs/proc/task_mmu.c:2242:27: error: 'pagemap_release' undeclared here (not in a function); did you mean 'proc_map_release'?
2242 | .release = pagemap_release,
| ^~~~~~~~~~~~~~~
| proc_map_release
fs/proc/task_mmu.c:2246:2: error: #endif without #if
2246 | #endif /* CONFIG_PROC_PAGE_MONITOR */
| ^~~~~
cc1: some warnings being treated as errors
vim +2059 fs/proc/task_mmu.c
2047
2048 static int pagemap_scan_pte_hole(unsigned long addr, unsigned long end,
2049 int depth, struct mm_walk *walk)
2050 {
2051 unsigned long n_pages = (end - addr)/PAGE_SIZE;
2052 struct pagemap_scan_private *p = walk->private;
2053 struct vm_area_struct *vma = walk->vma;
2054 int ret = 0;
2055
2056 if (!vma)
2057 return 0;
2058
> 2059 if (p->max_pages && p->found_pages + n_pages > p->max_pages)
> 2060 n_pages = p->max_pages - p->found_pages;
2061
> 2062 ret = pagemap_scan_output(false, vma->vm_file, false, false, p, addr,
2063 n_pages);
2064 return ret;
2065 }
2066
2067 static const struct mm_walk_ops pagemap_scan_ops = {
> 2068 .test_walk = pagemap_scan_test_walk,
> 2069 .pmd_entry = pagemap_scan_pmd_entry,
2070 .pte_hole = pagemap_scan_pte_hole,
2071 .hugetlb_entry = pagemap_scan_hugetlb_entry,
2072 };
2073
2074 static int pagemap_scan_args_valid(struct pm_scan_arg *arg, unsigned long start,
2075 struct page_region __user *vec)
2076 {
2077 /* Detect illegal size, flags, len and masks */
2078 if (arg->size != sizeof(struct pm_scan_arg))
2079 return -EINVAL;
> 2080 if (arg->flags & ~PM_SCAN_OPS)
2081 return -EINVAL;
2082 if (!arg->len)
2083 return -EINVAL;
2084 if ((arg->required_mask | arg->anyof_mask | arg->excluded_mask |
> 2085 arg->return_mask) & ~PM_SCAN_BITS_ALL)
2086 return -EINVAL;
2087 if (!arg->required_mask && !arg->anyof_mask &&
2088 !arg->excluded_mask)
2089 return -EINVAL;
2090 if (!arg->return_mask)
2091 return -EINVAL;
2092
2093 /* Validate memory ranges */
2094 if (!(arg->flags & PM_SCAN_OP_GET))
2095 return -EINVAL;
2096 if (!arg->vec)
2097 return -EINVAL;
2098 if (arg->vec_len == 0)
2099 return -EINVAL;
2100
2101 if (!IS_ALIGNED(start, PAGE_SIZE))
2102 return -EINVAL;
2103 if (!access_ok((void __user *)start, arg->len))
2104 return -EFAULT;
2105
> 2106 if (!PM_SCAN_DO_UFFD_WP(arg))
2107 return 0;
2108
2109 if ((arg->required_mask | arg->anyof_mask | arg->excluded_mask) &
2110 ~PAGE_IS_WRITTEN)
2111 return -EINVAL;
2112
2113 return 0;
2114 }
2115
2116 static long do_pagemap_scan(struct mm_struct *mm,
2117 struct pm_scan_arg __user *uarg)
2118 {
2119 unsigned long start, end, walk_start, walk_end;
2120 unsigned long empty_slots, vec_index = 0;
2121 struct mmu_notifier_range range;
2122 struct page_region __user *vec;
> 2123 struct pagemap_scan_private p;
2124 struct pm_scan_arg arg;
2125 int ret = 0;
2126
2127 if (copy_from_user(&arg, uarg, sizeof(arg)))
2128 return -EFAULT;
2129
2130 start = untagged_addr((unsigned long)arg.start);
2131 vec = (struct page_region *)untagged_addr((unsigned long)arg.vec);
2132
2133 ret = pagemap_scan_args_valid(&arg, start, vec);
2134 if (ret)
2135 return ret;
2136
2137 end = start + arg.len;
2138 p.max_pages = arg.max_pages;
2139 p.found_pages = 0;
2140 p.flags = arg.flags;
2141 p.required_mask = arg.required_mask;
2142 p.anyof_mask = arg.anyof_mask;
2143 p.excluded_mask = arg.excluded_mask;
2144 p.return_mask = arg.return_mask;
2145 p.cur.len = 0;
2146 p.cur.start = 0;
2147 p.vec = NULL;
> 2148 p.vec_len = PAGEMAP_WALK_SIZE >> PAGE_SHIFT;
2149
2150 /*
2151 * Allocate smaller buffer to get output from inside the page walk
2152 * functions and walk page range in PAGEMAP_WALK_SIZE size chunks. As
2153 * we want to return output to user in compact form where no two
2154 * consecutive regions should be continuous and have the same flags.
2155 * So store the latest element in p.cur between different walks and
2156 * store the p.cur at the end of the walk to the user buffer.
2157 */
2158 p.vec = kmalloc_array(p.vec_len, sizeof(*p.vec), GFP_KERNEL);
2159 if (!p.vec)
2160 return -ENOMEM;
2161
2162 if (p.flags & PM_SCAN_OP_WP) {
2163 mmu_notifier_range_init(&range, MMU_NOTIFY_PROTECTION_VMA, 0,
2164 vma->vm_mm, start, end);
2165 mmu_notifier_invalidate_range_start(&range);
2166 }
2167
2168 walk_start = walk_end = start;
2169 while (walk_end < end && !ret) {
2170 p.vec_index = 0;
2171
2172 empty_slots = arg.vec_len - vec_index;
> 2173 p.vec_len = min(p.vec_len, empty_slots);
2174
> 2175 walk_end = (walk_start + PAGEMAP_WALK_SIZE) & PAGEMAP_WALK_MASK;
2176 if (walk_end > end)
2177 walk_end = end;
2178
2179 ret = mmap_read_lock_killable(mm);
2180 if (ret)
2181 goto free_data;
2182 ret = walk_page_range(mm, walk_start, walk_end,
2183 &pagemap_scan_ops, &p);
2184 mmap_read_unlock(mm);
2185
> 2186 if (ret && ret != -ENOSPC && ret != PM_SCAN_FOUND_MAX_PAGES)
2187 goto free_data;
2188
2189 walk_start = walk_end;
2190 if (p.vec_index) {
2191 if (copy_to_user(&vec[vec_index], p.vec,
2192 p.vec_index * sizeof(*p.vec))) {
2193 /*
2194 * Return error even though the OP succeeded
2195 */
2196 ret = -EFAULT;
2197 goto free_data;
2198 }
2199 vec_index += p.vec_index;
2200 }
2201 }
2202
2203 if (p.flags & PM_SCAN_OP_WP) {
2204 mmu_notifier_invalidate_range_end(&range);
2205 flush_tlb_mm_range(mm, start, end, PAGE_SHIFT, false);
2206 }
2207
2208 if (p.cur.len) {
2209 if (copy_to_user(&vec[vec_index], &p.cur, sizeof(*p.vec))) {
2210 ret = -EFAULT;
2211 goto free_data;
2212 }
2213 vec_index++;
2214 }
2215
2216 ret = vec_index;
2217
2218 free_data:
2219 kfree(p.vec);
2220 return ret;
2221 }
2222
2223 static long do_pagemap_cmd(struct file *file, unsigned int cmd,
2224 unsigned long arg)
2225 {
2226 struct pm_scan_arg __user *uarg = (struct pm_scan_arg __user *)arg;
2227 struct mm_struct *mm = file->private_data;
2228
2229 switch (cmd) {
2230 case PAGEMAP_SCAN:
2231 return do_pagemap_scan(mm, uarg);
2232
2233 default:
2234 return -EINVAL;
2235 }
2236 }
2237
2238 const struct file_operations proc_pagemap_operations = {
2239 .llseek = mem_lseek, /* borrow this */
> 2240 .read = pagemap_read,
> 2241 .open = pagemap_open,
> 2242 .release = pagemap_release,
2243 .unlocked_ioctl = do_pagemap_cmd,
2244 .compat_ioctl = do_pagemap_cmd,
2245 };
2246 #endif /* CONFIG_PROC_PAGE_MONITOR */
2247
Muhammad, On Mon, Apr 17, 2023 at 05:56:27PM +0500, Muhammad Usama Anjum wrote: > +static int pagemap_scan_pmd_entry(pmd_t *pmd, unsigned long start, > + unsigned long end, struct mm_walk *walk) > +{ > + struct pagemap_scan_private *p = walk->private; > + struct vm_area_struct *vma = walk->vma; > + unsigned long addr = end; > + pte_t *pte, *orig_pte; > + spinlock_t *ptl; > + bool is_written; > + int ret = 0; > + > +#ifdef CONFIG_TRANSPARENT_HUGEPAGE > + ptl = pmd_trans_huge_lock(pmd, vma); > + if (ptl) { > + unsigned long n_pages = (end - start)/PAGE_SIZE; > + > + if (p->max_pages && n_pages > p->max_pages - p->found_pages) > + n_pages = p->max_pages - p->found_pages; > + > + is_written = !is_pmd_uffd_wp(*pmd); > + > + /* > + * Break huge page into small pages if the WP operation need to > + * be performed is on a portion of the huge page. > + */ > + if (is_written && PM_SCAN_DO_UFFD_WP(p) && > + n_pages < HPAGE_SIZE/PAGE_SIZE) { > + spin_unlock(ptl); > + split_huge_pmd(vma, pmd, start); > + goto process_smaller_pages; > + } > + > + ret = pagemap_scan_output(is_written, vma->vm_file, > + pmd_present(*pmd), is_swap_pmd(*pmd), > + p, start, n_pages); > + > + if (ret >= 0 && is_written && PM_SCAN_DO_UFFD_WP(p)) > + make_uffd_wp_pmd(vma, addr, pmd); > + > + spin_unlock(ptl); > + return ret; > + } > +process_smaller_pages: > + if (pmd_trans_unstable(pmd)) > + return 0; > +#endif > + > + pte = pte_offset_map_lock(vma->vm_mm, pmd, start, &ptl); > + for (addr = start; addr < end && !ret; pte++, addr += PAGE_SIZE) { > + is_written = !is_pte_uffd_wp(*pte); > + > + ret = pagemap_scan_output(is_written, vma->vm_file, > + pte_present(*pte), is_swap_pte(*pte), > + p, addr, 1); > + > + if (ret >= 0 && is_written && PM_SCAN_DO_UFFD_WP(p)) > + make_uffd_wp_pte(vma, addr, pte); > + } > + pte_unmap_unlock(orig_pte, ptl); IIUC tlb flushes, mmu notifications are still missing here, am I right? Thanks, > + > + cond_resched(); > + return ret; > +}
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c index 38b19a757281..3d091095d404 100644 --- a/fs/proc/task_mmu.c +++ b/fs/proc/task_mmu.c @@ -19,6 +19,7 @@ #include <linux/shmem_fs.h> #include <linux/uaccess.h> #include <linux/pkeys.h> +#include <linux/minmax.h> #include <asm/elf.h> #include <asm/tlb.h> @@ -1767,11 +1768,488 @@ static int pagemap_release(struct inode *inode, struct file *file) return 0; } +#define PM_SCAN_FOUND_MAX_PAGES (1) +#define PM_SCAN_BITS_ALL (PAGE_IS_WRITTEN | PAGE_IS_FILE | \ + PAGE_IS_PRESENT | PAGE_IS_SWAPPED) +#define PM_SCAN_OPS (PM_SCAN_OP_GET | PM_SCAN_OP_WP) +#define PM_SCAN_DO_UFFD_WP(a) (a->flags & PM_SCAN_OP_WP) +#define PM_SCAN_BITMAP(wt, file, present, swap) \ + ((wt) | ((file) << 1) | ((present) << 2) | ((swap) << 3)) + +struct pagemap_scan_private { + struct page_region *vec; + struct page_region cur; + unsigned long vec_len, vec_index; + unsigned int max_pages, found_pages, flags; + unsigned long required_mask, anyof_mask, excluded_mask, return_mask; +}; + +static inline bool is_pte_uffd_wp(pte_t pte) +{ + return (pte_present(pte) && pte_uffd_wp(pte)) || + pte_swp_uffd_wp_any(pte); +} + +static inline void make_uffd_wp_pte(struct vm_area_struct *vma, + unsigned long addr, pte_t *pte) +{ + pte_t ptent = *pte; + + if (pte_present(ptent)) { + pte_t old_pte; + + old_pte = ptep_modify_prot_start(vma, addr, pte); + ptent = pte_mkuffd_wp(ptent); + ptep_modify_prot_commit(vma, addr, pte, old_pte, ptent); + } else if (is_swap_pte(ptent)) { + ptent = pte_swp_mkuffd_wp(ptent); + set_pte_at(vma->vm_mm, addr, pte, ptent); + } +} + +#ifdef CONFIG_TRANSPARENT_HUGEPAGE +static inline bool is_pmd_uffd_wp(pmd_t pmd) +{ + return (pmd_present(pmd) && pmd_uffd_wp(pmd)) || + (is_swap_pmd(pmd) && pmd_swp_uffd_wp(pmd)); +} + +static inline void make_uffd_wp_pmd(struct vm_area_struct *vma, + unsigned long addr, pmd_t *pmdp) +{ + pmd_t old, pmd = *pmdp; + + if (pmd_present(pmd)) { + old = pmdp_invalidate_ad(vma, addr, pmdp); + pmd = pmd_mkuffd_wp(old); + set_pmd_at(vma->vm_mm, addr, pmdp, pmd); + } else if (is_migration_entry(pmd_to_swp_entry(pmd))) { + pmd = pmd_swp_mkuffd_wp(pmd); + set_pmd_at(vma->vm_mm, addr, pmdp, pmd); + } +} +#endif + +#ifdef CONFIG_HUGETLB_PAGE +static inline bool is_huge_pte_uffd_wp(pte_t pte) +{ + return ((pte_present(pte) && huge_pte_uffd_wp(pte)) || + pte_swp_uffd_wp_any(pte)); +} + +static inline void make_uffd_wp_huge_pte(struct vm_area_struct *vma, + unsigned long addr, pte_t *ptep, + pte_t ptent) +{ + pte_t old_pte; + + if (!huge_pte_none(ptent)) { + old_pte = huge_ptep_modify_prot_start(vma, addr, ptep); + ptent = huge_pte_mkuffd_wp(old_pte); + ptep_modify_prot_commit(vma, addr, ptep, old_pte, ptent); + } else { + set_huge_pte_at(vma->vm_mm, addr, ptep, + make_pte_marker(PTE_MARKER_UFFD_WP)); + } +} +#endif + +static inline bool pagemap_scan_check_page_written(struct pagemap_scan_private *p) +{ + return (p->required_mask | p->anyof_mask | p->excluded_mask) & + PAGE_IS_WRITTEN; +} + +static int pagemap_scan_test_walk(unsigned long start, unsigned long end, + struct mm_walk *walk) +{ + struct pagemap_scan_private *p = walk->private; + struct vm_area_struct *vma = walk->vma; + + if (pagemap_scan_check_page_written(p) && (!userfaultfd_wp(vma) || + !userfaultfd_wp_async(vma))) + return -EPERM; + + if (vma->vm_flags & VM_PFNMAP) + return 1; + + return 0; +} + +static int pagemap_scan_output(bool wt, bool file, bool pres, bool swap, + struct pagemap_scan_private *p, + unsigned long addr, unsigned int n_pages) +{ + unsigned long bitmap = PM_SCAN_BITMAP(wt, file, pres, swap); + struct page_region *cur = &p->cur; + + if (!n_pages) + return -EINVAL; + + if ((p->required_mask & bitmap) != p->required_mask) + return 0; + if (p->anyof_mask && !(p->anyof_mask & bitmap)) + return 0; + if (p->excluded_mask & bitmap) + return 0; + + bitmap &= p->return_mask; + if (!bitmap) + return 0; + + if (cur->bitmap == bitmap && + cur->start + cur->len * PAGE_SIZE == addr) { + cur->len += n_pages; + p->found_pages += n_pages; + + if (p->max_pages && (p->found_pages == p->max_pages)) + return PM_SCAN_FOUND_MAX_PAGES; + + return 0; + } + + /* + * All data is copied to cur first. When more data is found, we push + * cur to vec and copy new data to cur. The vec_index represents the + * current index of vec array. We add 1 to the vec_index while + * performing checks to account for data in cur. + */ + if (p->vec_index && (p->vec_index + 1) >= p->vec_len) + return -ENOSPC; + + if (cur->len) { + memcpy(&p->vec[p->vec_index], cur, sizeof(*p->vec)); + p->vec_index++; + } + + cur->start = addr; + cur->len = n_pages; + cur->bitmap = bitmap; + p->found_pages += n_pages; + + if (p->max_pages && (p->found_pages == p->max_pages)) + return PM_SCAN_FOUND_MAX_PAGES; + + return 0; +} + +static int pagemap_scan_pmd_entry(pmd_t *pmd, unsigned long start, + unsigned long end, struct mm_walk *walk) +{ + struct pagemap_scan_private *p = walk->private; + struct vm_area_struct *vma = walk->vma; + unsigned long addr = end; + pte_t *pte, *orig_pte; + spinlock_t *ptl; + bool is_written; + int ret = 0; + +#ifdef CONFIG_TRANSPARENT_HUGEPAGE + ptl = pmd_trans_huge_lock(pmd, vma); + if (ptl) { + unsigned long n_pages = (end - start)/PAGE_SIZE; + + if (p->max_pages && n_pages > p->max_pages - p->found_pages) + n_pages = p->max_pages - p->found_pages; + + is_written = !is_pmd_uffd_wp(*pmd); + + /* + * Break huge page into small pages if the WP operation need to + * be performed is on a portion of the huge page. + */ + if (is_written && PM_SCAN_DO_UFFD_WP(p) && + n_pages < HPAGE_SIZE/PAGE_SIZE) { + spin_unlock(ptl); + split_huge_pmd(vma, pmd, start); + goto process_smaller_pages; + } + + ret = pagemap_scan_output(is_written, vma->vm_file, + pmd_present(*pmd), is_swap_pmd(*pmd), + p, start, n_pages); + + if (ret >= 0 && is_written && PM_SCAN_DO_UFFD_WP(p)) + make_uffd_wp_pmd(vma, addr, pmd); + + spin_unlock(ptl); + return ret; + } +process_smaller_pages: + if (pmd_trans_unstable(pmd)) + return 0; +#endif + + pte = pte_offset_map_lock(vma->vm_mm, pmd, start, &ptl); + for (addr = start; addr < end && !ret; pte++, addr += PAGE_SIZE) { + is_written = !is_pte_uffd_wp(*pte); + + ret = pagemap_scan_output(is_written, vma->vm_file, + pte_present(*pte), is_swap_pte(*pte), + p, addr, 1); + + if (ret >= 0 && is_written && PM_SCAN_DO_UFFD_WP(p)) + make_uffd_wp_pte(vma, addr, pte); + } + pte_unmap_unlock(orig_pte, ptl); + + cond_resched(); + return ret; +} + +#ifdef CONFIG_HUGETLB_PAGE +static int pagemap_scan_hugetlb_entry(pte_t *ptep, unsigned long hmask, + unsigned long start, unsigned long end, + struct mm_walk *walk) +{ + unsigned long n_pages = (end - start)/PAGE_SIZE; + struct pagemap_scan_private *p = walk->private; + struct vm_area_struct *vma = walk->vma; + struct hstate *h = hstate_vma(vma); + int ret = -EPERM; + spinlock_t *ptl; + bool is_written; + pte_t pte; + + if (p->max_pages && n_pages > p->max_pages - p->found_pages) + n_pages = p->max_pages - p->found_pages; + + if (PM_SCAN_DO_UFFD_WP(p)) { + i_mmap_lock_write(vma->vm_file->f_mapping); + ptl = huge_pte_lock(h, vma->vm_mm, ptep); + } + + pte = huge_ptep_get(ptep); + is_written = !is_huge_pte_uffd_wp(pte); + + /* + * Partial hugetlb page clear isn't supported + */ + if (is_written && PM_SCAN_DO_UFFD_WP(p) && + n_pages < HPAGE_SIZE/PAGE_SIZE) + goto unlock_and_return; + + ret = pagemap_scan_output(is_written, vma->vm_file, pte_present(pte), + is_swap_pte(pte), p, start, n_pages); + if (ret < 0) + goto unlock_and_return; + + if (is_written && PM_SCAN_DO_UFFD_WP(p)) { + make_uffd_wp_huge_pte(vma, start, ptep, pte); +#define __HAVE_ARCH_FLUSH_HUGETLB_TLB_RANGE + flush_hugetlb_tlb_range(vma, start, end); +#endif + } + +unlock_and_return: + if (PM_SCAN_DO_UFFD_WP(p)) { + spin_unlock(ptl); + i_mmap_unlock_write(vma->vm_file->f_mapping); + } + + return ret; +} +#else +#define pagemap_scan_hugetlb_entry NULL +#endif + +static int pagemap_scan_pte_hole(unsigned long addr, unsigned long end, + int depth, struct mm_walk *walk) +{ + unsigned long n_pages = (end - addr)/PAGE_SIZE; + struct pagemap_scan_private *p = walk->private; + struct vm_area_struct *vma = walk->vma; + int ret = 0; + + if (!vma) + return 0; + + if (p->max_pages && p->found_pages + n_pages > p->max_pages) + n_pages = p->max_pages - p->found_pages; + + ret = pagemap_scan_output(false, vma->vm_file, false, false, p, addr, + n_pages); + return ret; +} + +static const struct mm_walk_ops pagemap_scan_ops = { + .test_walk = pagemap_scan_test_walk, + .pmd_entry = pagemap_scan_pmd_entry, + .pte_hole = pagemap_scan_pte_hole, + .hugetlb_entry = pagemap_scan_hugetlb_entry, +}; + +static int pagemap_scan_args_valid(struct pm_scan_arg *arg, unsigned long start, + struct page_region __user *vec) +{ + /* Detect illegal size, flags, len and masks */ + if (arg->size != sizeof(struct pm_scan_arg)) + return -EINVAL; + if (arg->flags & ~PM_SCAN_OPS) + return -EINVAL; + if (!arg->len) + return -EINVAL; + if ((arg->required_mask | arg->anyof_mask | arg->excluded_mask | + arg->return_mask) & ~PM_SCAN_BITS_ALL) + return -EINVAL; + if (!arg->required_mask && !arg->anyof_mask && + !arg->excluded_mask) + return -EINVAL; + if (!arg->return_mask) + return -EINVAL; + + /* Validate memory ranges */ + if (!(arg->flags & PM_SCAN_OP_GET)) + return -EINVAL; + if (!arg->vec) + return -EINVAL; + if (arg->vec_len == 0) + return -EINVAL; + + if (!IS_ALIGNED(start, PAGE_SIZE)) + return -EINVAL; + if (!access_ok((void __user *)start, arg->len)) + return -EFAULT; + + if (!PM_SCAN_DO_UFFD_WP(arg)) + return 0; + + if ((arg->required_mask | arg->anyof_mask | arg->excluded_mask) & + ~PAGE_IS_WRITTEN) + return -EINVAL; + + return 0; +} + +static long do_pagemap_scan(struct mm_struct *mm, + struct pm_scan_arg __user *uarg) +{ + unsigned long start, end, walk_start, walk_end; + unsigned long empty_slots, vec_index = 0; + struct mmu_notifier_range range; + struct page_region __user *vec; + struct pagemap_scan_private p; + struct pm_scan_arg arg; + int ret = 0; + + if (copy_from_user(&arg, uarg, sizeof(arg))) + return -EFAULT; + + start = untagged_addr((unsigned long)arg.start); + vec = (struct page_region *)untagged_addr((unsigned long)arg.vec); + + ret = pagemap_scan_args_valid(&arg, start, vec); + if (ret) + return ret; + + end = start + arg.len; + p.max_pages = arg.max_pages; + p.found_pages = 0; + p.flags = arg.flags; + p.required_mask = arg.required_mask; + p.anyof_mask = arg.anyof_mask; + p.excluded_mask = arg.excluded_mask; + p.return_mask = arg.return_mask; + p.cur.len = 0; + p.cur.start = 0; + p.vec = NULL; + p.vec_len = PAGEMAP_WALK_SIZE >> PAGE_SHIFT; + + /* + * Allocate smaller buffer to get output from inside the page walk + * functions and walk page range in PAGEMAP_WALK_SIZE size chunks. As + * we want to return output to user in compact form where no two + * consecutive regions should be continuous and have the same flags. + * So store the latest element in p.cur between different walks and + * store the p.cur at the end of the walk to the user buffer. + */ + p.vec = kmalloc_array(p.vec_len, sizeof(*p.vec), GFP_KERNEL); + if (!p.vec) + return -ENOMEM; + + if (p.flags & PM_SCAN_OP_WP) { + mmu_notifier_range_init(&range, MMU_NOTIFY_PROTECTION_VMA, 0, + vma->vm_mm, start, end); + mmu_notifier_invalidate_range_start(&range); + } + + walk_start = walk_end = start; + while (walk_end < end && !ret) { + p.vec_index = 0; + + empty_slots = arg.vec_len - vec_index; + p.vec_len = min(p.vec_len, empty_slots); + + walk_end = (walk_start + PAGEMAP_WALK_SIZE) & PAGEMAP_WALK_MASK; + if (walk_end > end) + walk_end = end; + + ret = mmap_read_lock_killable(mm); + if (ret) + goto free_data; + ret = walk_page_range(mm, walk_start, walk_end, + &pagemap_scan_ops, &p); + mmap_read_unlock(mm); + + if (ret && ret != -ENOSPC && ret != PM_SCAN_FOUND_MAX_PAGES) + goto free_data; + + walk_start = walk_end; + if (p.vec_index) { + if (copy_to_user(&vec[vec_index], p.vec, + p.vec_index * sizeof(*p.vec))) { + /* + * Return error even though the OP succeeded + */ + ret = -EFAULT; + goto free_data; + } + vec_index += p.vec_index; + } + } + + if (p.flags & PM_SCAN_OP_WP) { + mmu_notifier_invalidate_range_end(&range); + flush_tlb_mm_range(mm, start, end, PAGE_SHIFT, false); + } + + if (p.cur.len) { + if (copy_to_user(&vec[vec_index], &p.cur, sizeof(*p.vec))) { + ret = -EFAULT; + goto free_data; + } + vec_index++; + } + + ret = vec_index; + +free_data: + kfree(p.vec); + return ret; +} + +static long do_pagemap_cmd(struct file *file, unsigned int cmd, + unsigned long arg) +{ + struct pm_scan_arg __user *uarg = (struct pm_scan_arg __user *)arg; + struct mm_struct *mm = file->private_data; + + switch (cmd) { + case PAGEMAP_SCAN: + return do_pagemap_scan(mm, uarg); + + default: + return -EINVAL; + } +} + const struct file_operations proc_pagemap_operations = { .llseek = mem_lseek, /* borrow this */ .read = pagemap_read, .open = pagemap_open, .release = pagemap_release, + .unlocked_ioctl = do_pagemap_cmd, + .compat_ioctl = do_pagemap_cmd, }; #endif /* CONFIG_PROC_PAGE_MONITOR */ diff --git a/include/uapi/linux/fs.h b/include/uapi/linux/fs.h index b7b56871029c..47879c38ce2f 100644 --- a/include/uapi/linux/fs.h +++ b/include/uapi/linux/fs.h @@ -305,4 +305,57 @@ typedef int __bitwise __kernel_rwf_t; #define RWF_SUPPORTED (RWF_HIPRI | RWF_DSYNC | RWF_SYNC | RWF_NOWAIT |\ RWF_APPEND) +/* Pagemap ioctl */ +#define PAGEMAP_SCAN _IOWR('f', 16, struct pm_scan_arg) + +/* Bits are set in the bitmap of the page_region and masks in pm_scan_args */ +#define PAGE_IS_WRITTEN (1 << 0) +#define PAGE_IS_FILE (1 << 1) +#define PAGE_IS_PRESENT (1 << 2) +#define PAGE_IS_SWAPPED (1 << 3) + +/* + * struct page_region - Page region with bitmap flags + * @start: Start of the region + * @len: Length of the region in pages + * bitmap: Bits sets for the region + */ +struct page_region { + __u64 start; + __u64 len; + __u64 bitmap; +}; + +/* + * struct pm_scan_arg - Pagemap ioctl argument + * @size: Size of the structure + * @flags: Flags for the IOCTL + * @start: Starting address of the region + * @len: Length of the region (All the pages in this length are included) + * @vec: Address of page_region struct array for output + * @vec_len: Length of the page_region struct array + * @max_pages: Optional max return pages + * @required_mask: Required mask - All of these bits have to be set in the PTE + * @anyof_mask: Any mask - Any of these bits are set in the PTE + * @excluded_mask: Exclude mask - None of these bits are set in the PTE + * @return_mask: Bits that are to be reported in page_region + */ +struct pm_scan_arg { + __u64 size; + __u64 flags; + __u64 start; + __u64 len; + __u64 vec; + __u64 vec_len; + __u64 max_pages; + __u64 required_mask; + __u64 anyof_mask; + __u64 excluded_mask; + __u64 return_mask; +}; + +/* Supported flags */ +#define PM_SCAN_OP_GET (1 << 0) +#define PM_SCAN_OP_WP (1 << 1) + #endif /* _UAPI_LINUX_FS_H */
This IOCTL, PAGEMAP_SCAN on pagemap file can be used to get and/or clear the info about page table entries. The following operations are supported in this ioctl: - Get the information if the pages have been written-to (PAGE_IS_WRITTEN), file mapped (PAGE_IS_FILE), present (PAGE_IS_PRESENT) or swapped (PAGE_IS_SWAPPED). - Find pages which have been written-to and write protect the pages (atomic PAGE_IS_WRITTEN + PAGEMAP_WP_ENGAGE) This IOCTL can be extended to get information about more PTE bits. Signed-off-by: Muhammad Usama Anjum <usama.anjum@collabora.com> --- Changes in v13: - Review updates - mmap_read_lock_killable() instead of mmap_read_lock() - Replace uffd_wp_range() with helpers which increases performance drastically for OP_WP operations by reducing the number of tlb flushing etc - Add MMU_NOTIFY_PROTECTION_VMA notification for the memory range Changes in v12: - Add hugetlb support to cover all memory types - Merge "userfaultfd: Define dummy uffd_wp_range()" with this patch - Review updates to the code Changes in v11: - Find written pages in a better way - Fix a corner case (thanks Paul) - Improve the code/comments - remove ENGAGE_WP + ! GET operation - shorten the commit message in favour of moving documentation to pagemap.rst Changes in v10: - move changes in tools/include/uapi/linux/fs.h to separate patch - update commit message Change in v8: - Correct is_pte_uffd_wp() - Improve readability and error checks - Remove some un-needed code Changes in v7: - Rebase on top of latest next - Fix some corner cases - Base soft-dirty on the uffd wp async - Update the terminologies - Optimize the memory usage inside the ioctl Changes in v6: - Rename variables and update comments - Make IOCTL independent of soft_dirty config - Change masks and bitmap type to _u64 - Improve code quality Changes in v5: - Remove tlb flushing even for clear operation Changes in v4: - Update the interface and implementation Changes in v3: - Tighten the user-kernel interface by using explicit types and add more error checking Changes in v2: - Convert the interface from syscall to ioctl - Remove pidfd support as it doesn't make sense in ioctl task_mmu task_mmu task_mmu.c --- fs/proc/task_mmu.c | 478 ++++++++++++++++++++++++++++++++++++++++ include/uapi/linux/fs.h | 53 +++++ 2 files changed, 531 insertions(+)