[l1k:smsc95xx_5.17 74/887] arch/arm/lib/uaccess_with_memcpy.c:137:1: warning: no previous prototype for '__copy_to_user_memcpy'

From: kernel test robot
Date: Fri Apr 08 2022 - 13:46:09 EST

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tree: https://github.com/l1k/linux smsc95xx_5.17
head: 05d68ced287b30f62f18f95b5476135ef669804a
commit: 375b90433562ce3545ccda0376716268ff974114 [74/887] Improve __copy_to_user and __copy_from_user performance
config: arm-randconfig-p002-20220408 (https://download.01.org/0day-ci/archive/20220409/202204090126.gjg3vnZv-lkp@xxxxxxxxx/config)
compiler: arm-linux-gnueabi-gcc (GCC) 11.2.0
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# https://github.com/l1k/linux/commit/375b90433562ce3545ccda0376716268ff974114
git remote add l1k https://github.com/l1k/linux
git fetch --no-tags l1k smsc95xx_5.17
git checkout 375b90433562ce3545ccda0376716268ff974114
# save the config file to linux build tree
mkdir build_dir
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.2.0 make.cross O=build_dir ARCH=arm SHELL=/bin/bash
reproduce (cppcheck warning):
# apt-get install cppcheck
git checkout 375b90433562ce3545ccda0376716268ff974114
cppcheck --quiet --enable=style,performance,portability --template=gcc FILE

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@xxxxxxxxx>

All warnings (new ones prefixed by >>):

>> arch/arm/lib/uaccess_with_memcpy.c:137:1: warning: no previous prototype for '__copy_to_user_memcpy' [-Wmissing-prototypes]
137 | __copy_to_user_memcpy(void __user *to, const void *from, unsigned long n)
| ^~~~~~~~~~~~~~~~~~~~~
>> arch/arm/lib/uaccess_with_memcpy.c:190:1: warning: no previous prototype for '__copy_from_user_memcpy' [-Wmissing-prototypes]
190 | __copy_from_user_memcpy(void *to, const void __user *from, unsigned long n)
| ^~~~~~~~~~~~~~~~~~~~~~~

cppcheck possible warnings: (new ones prefixed by >>, may not real problems)

>> arch/arm/mm/fault.c:539:28: warning: Shifting signed 32-bit value by 31 bits is implementation-defined behaviour [shiftTooManyBitsSigned]
if (!inf->fn(addr, fsr & ~FSR_LNX_PF, regs))
^
arch/arm/mm/fault.c:569:28: warning: Shifting signed 32-bit value by 31 bits is implementation-defined behaviour [shiftTooManyBitsSigned]
if (!inf->fn(addr, ifsr | FSR_LNX_PF, regs))
^
>> arch/arm/mm/fault.c:539:28: warning: Signed integer overflow for expression '1<<31'. [integerOverflow]
if (!inf->fn(addr, fsr & ~FSR_LNX_PF, regs))
^
arch/arm/mm/fault.c:569:28: warning: Signed integer overflow for expression '1<<31'. [integerOverflow]
if (!inf->fn(addr, ifsr | FSR_LNX_PF, regs))
^
arch/arm/mm/fault.c:279:12: warning: Shifting signed 32-bit value by 31 bits is implementation-defined behaviour [shiftTooManyBitsSigned]
if (fsr & FSR_LNX_PF) {
^
arch/arm/mm/fault.c:279:12: warning: Signed integer overflow for expression '1<<31'. [integerOverflow]
if (fsr & FSR_LNX_PF) {
^

vim +/__copy_to_user_memcpy +137 arch/arm/lib/uaccess_with_memcpy.c

375b90433562ce popcornmix 2016-11-28 135
375b90433562ce popcornmix 2016-11-28 136 unsigned long noinline
cb9dc92c0a1b76 Nicolas Pitre 2009-05-21 @137 __copy_to_user_memcpy(void __user *to, const void *from, unsigned long n)
39ec58f3fea47c Lennert Buytenhek 2009-03-09 138 {
c014953d84ec21 Russell King 2015-12-05 139 unsigned long ua_flags;
39ec58f3fea47c Lennert Buytenhek 2009-03-09 140 int atomic;
39ec58f3fea47c Lennert Buytenhek 2009-03-09 141
db68ce10c4f0a2 Al Viro 2017-03-20 142 if (uaccess_kernel()) {
39ec58f3fea47c Lennert Buytenhek 2009-03-09 143 memcpy((void *)to, from, n);
39ec58f3fea47c Lennert Buytenhek 2009-03-09 144 return 0;
39ec58f3fea47c Lennert Buytenhek 2009-03-09 145 }
39ec58f3fea47c Lennert Buytenhek 2009-03-09 146
39ec58f3fea47c Lennert Buytenhek 2009-03-09 147 /* the mmap semaphore is taken only if not in an atomic context */
0f64b247e63ac8 Nicolas Pitre 2015-08-12 148 atomic = faulthandler_disabled();
39ec58f3fea47c Lennert Buytenhek 2009-03-09 149
39ec58f3fea47c Lennert Buytenhek 2009-03-09 150 if (!atomic)
d8ed45c5dcd455 Michel Lespinasse 2020-06-08 151 mmap_read_lock(current->mm);
39ec58f3fea47c Lennert Buytenhek 2009-03-09 152 while (n) {
39ec58f3fea47c Lennert Buytenhek 2009-03-09 153 pte_t *pte;
39ec58f3fea47c Lennert Buytenhek 2009-03-09 154 spinlock_t *ptl;
39ec58f3fea47c Lennert Buytenhek 2009-03-09 155 int tocopy;
39ec58f3fea47c Lennert Buytenhek 2009-03-09 156
39ec58f3fea47c Lennert Buytenhek 2009-03-09 157 while (!pin_page_for_write(to, &pte, &ptl)) {
39ec58f3fea47c Lennert Buytenhek 2009-03-09 158 if (!atomic)
d8ed45c5dcd455 Michel Lespinasse 2020-06-08 159 mmap_read_unlock(current->mm);
39ec58f3fea47c Lennert Buytenhek 2009-03-09 160 if (__put_user(0, (char __user *)to))
39ec58f3fea47c Lennert Buytenhek 2009-03-09 161 goto out;
39ec58f3fea47c Lennert Buytenhek 2009-03-09 162 if (!atomic)
d8ed45c5dcd455 Michel Lespinasse 2020-06-08 163 mmap_read_lock(current->mm);
39ec58f3fea47c Lennert Buytenhek 2009-03-09 164 }
39ec58f3fea47c Lennert Buytenhek 2009-03-09 165
39ec58f3fea47c Lennert Buytenhek 2009-03-09 166 tocopy = (~(unsigned long)to & ~PAGE_MASK) + 1;
39ec58f3fea47c Lennert Buytenhek 2009-03-09 167 if (tocopy > n)
39ec58f3fea47c Lennert Buytenhek 2009-03-09 168 tocopy = n;
39ec58f3fea47c Lennert Buytenhek 2009-03-09 169
c014953d84ec21 Russell King 2015-12-05 170 ua_flags = uaccess_save_and_enable();
39ec58f3fea47c Lennert Buytenhek 2009-03-09 171 memcpy((void *)to, from, tocopy);
c014953d84ec21 Russell King 2015-12-05 172 uaccess_restore(ua_flags);
39ec58f3fea47c Lennert Buytenhek 2009-03-09 173 to += tocopy;
39ec58f3fea47c Lennert Buytenhek 2009-03-09 174 from += tocopy;
39ec58f3fea47c Lennert Buytenhek 2009-03-09 175 n -= tocopy;
39ec58f3fea47c Lennert Buytenhek 2009-03-09 176
a3a9ea656d1925 Steven Capper 2013-10-14 177 if (pte)
39ec58f3fea47c Lennert Buytenhek 2009-03-09 178 pte_unmap_unlock(pte, ptl);
a3a9ea656d1925 Steven Capper 2013-10-14 179 else
a3a9ea656d1925 Steven Capper 2013-10-14 180 spin_unlock(ptl);
39ec58f3fea47c Lennert Buytenhek 2009-03-09 181 }
39ec58f3fea47c Lennert Buytenhek 2009-03-09 182 if (!atomic)
d8ed45c5dcd455 Michel Lespinasse 2020-06-08 183 mmap_read_unlock(current->mm);
39ec58f3fea47c Lennert Buytenhek 2009-03-09 184
39ec58f3fea47c Lennert Buytenhek 2009-03-09 185 out:
39ec58f3fea47c Lennert Buytenhek 2009-03-09 186 return n;
39ec58f3fea47c Lennert Buytenhek 2009-03-09 187 }
39ec58f3fea47c Lennert Buytenhek 2009-03-09 188
375b90433562ce popcornmix 2016-11-28 189 unsigned long noinline
375b90433562ce popcornmix 2016-11-28 @190 __copy_from_user_memcpy(void *to, const void __user *from, unsigned long n)
375b90433562ce popcornmix 2016-11-28 191 {
375b90433562ce popcornmix 2016-11-28 192 unsigned long ua_flags;
375b90433562ce popcornmix 2016-11-28 193 int atomic;
375b90433562ce popcornmix 2016-11-28 194
375b90433562ce popcornmix 2016-11-28 195 if (unlikely(uaccess_kernel())) {
375b90433562ce popcornmix 2016-11-28 196 memcpy(to, (const void *)from, n);
375b90433562ce popcornmix 2016-11-28 197 return 0;
375b90433562ce popcornmix 2016-11-28 198 }
375b90433562ce popcornmix 2016-11-28 199
375b90433562ce popcornmix 2016-11-28 200 /* the mmap semaphore is taken only if not in an atomic context */
375b90433562ce popcornmix 2016-11-28 201 atomic = in_atomic();
375b90433562ce popcornmix 2016-11-28 202
375b90433562ce popcornmix 2016-11-28 203 if (!atomic)
375b90433562ce popcornmix 2016-11-28 204 mmap_read_lock(current->mm);
375b90433562ce popcornmix 2016-11-28 205 while (n) {
375b90433562ce popcornmix 2016-11-28 206 pte_t *pte;
375b90433562ce popcornmix 2016-11-28 207 spinlock_t *ptl;
375b90433562ce popcornmix 2016-11-28 208 int tocopy;
375b90433562ce popcornmix 2016-11-28 209
375b90433562ce popcornmix 2016-11-28 210 while (!pin_page_for_read(from, &pte, &ptl)) {
375b90433562ce popcornmix 2016-11-28 211 char temp;
375b90433562ce popcornmix 2016-11-28 212 if (!atomic)
375b90433562ce popcornmix 2016-11-28 213 mmap_read_unlock(current->mm);
375b90433562ce popcornmix 2016-11-28 214 if (__get_user(temp, (char __user *)from))
375b90433562ce popcornmix 2016-11-28 215 goto out;
375b90433562ce popcornmix 2016-11-28 216 if (!atomic)
375b90433562ce popcornmix 2016-11-28 217 mmap_read_lock(current->mm);
375b90433562ce popcornmix 2016-11-28 218 }
375b90433562ce popcornmix 2016-11-28 219
375b90433562ce popcornmix 2016-11-28 220 tocopy = (~(unsigned long)from & ~PAGE_MASK) + 1;
375b90433562ce popcornmix 2016-11-28 221 if (tocopy > n)
375b90433562ce popcornmix 2016-11-28 222 tocopy = n;
375b90433562ce popcornmix 2016-11-28 223
375b90433562ce popcornmix 2016-11-28 224 ua_flags = uaccess_save_and_enable();
375b90433562ce popcornmix 2016-11-28 225 memcpy(to, (const void *)from, tocopy);
375b90433562ce popcornmix 2016-11-28 226 uaccess_restore(ua_flags);
375b90433562ce popcornmix 2016-11-28 227 to += tocopy;
375b90433562ce popcornmix 2016-11-28 228 from += tocopy;
375b90433562ce popcornmix 2016-11-28 229 n -= tocopy;
375b90433562ce popcornmix 2016-11-28 230
375b90433562ce popcornmix 2016-11-28 231 pte_unmap_unlock(pte, ptl);
375b90433562ce popcornmix 2016-11-28 232 }
375b90433562ce popcornmix 2016-11-28 233 if (!atomic)
375b90433562ce popcornmix 2016-11-28 234 mmap_read_unlock(current->mm);
375b90433562ce popcornmix 2016-11-28 235
375b90433562ce popcornmix 2016-11-28 236 out:
375b90433562ce popcornmix 2016-11-28 237 return n;
375b90433562ce popcornmix 2016-11-28 238 }
375b90433562ce popcornmix 2016-11-28 239

:::::: The code at line 137 was first introduced by commit
:::::: cb9dc92c0a1b76165c8c334402e27191084b2047 [ARM] lower overhead with alternative copy_to_user for small copies

:::::: TO: Nicolas Pitre <nico@xxxxxxx>
:::::: CC: Nicolas Pitre <nico@xxxxxxx>

--
0-DAY CI Kernel Test Service
https://01.org/lkp

Next message: kernel test robot: "[kas:lam 6/10] drivers/tee/tee_core.c:449:29: sparse: sparse: incorrect type in argument 1 (different address spaces)"
Previous message: Sean Christopherson: "Re: [PATCH v5 05/13] KVM: Extend the memslot to support fd-based private memory"
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