arch/arm64/kernel/hibernate.c:202:44: sparse: sparse: cast from restricted gfp_t

From: kernel test robot
Date: Tue Mar 30 2021 - 10:51:02 EST


tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head: 1e43c377a79f9189fea8f2711b399d4e8b4e609b
commit: 50f53fb721817a6efa541cca24f1b7caa84801c1 arm64: trans_pgd: make trans_pgd_map_page generic
date: 9 weeks ago
config: arm64-randconfig-s032-20210330 (attached as .config)
compiler: aarch64-linux-gcc (GCC) 9.3.0
reproduce:
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# apt-get install sparse
# sparse version: v0.6.3-279-g6d5d9b42-dirty
# https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=50f53fb721817a6efa541cca24f1b7caa84801c1
git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
git fetch --no-tags linus master
git checkout 50f53fb721817a6efa541cca24f1b7caa84801c1
# save the attached .config to linux build tree
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__' ARCH=arm64

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


sparse warnings: (new ones prefixed by >>)
arch/arm64/kernel/hibernate.c:181:39: sparse: sparse: cast to restricted gfp_t
>> arch/arm64/kernel/hibernate.c:202:44: sparse: sparse: cast from restricted gfp_t

vim +202 arch/arm64/kernel/hibernate.c

183
184 /*
185 * Copies length bytes, starting at src_start into an new page,
186 * perform cache maintenance, then maps it at the specified address low
187 * address as executable.
188 *
189 * This is used by hibernate to copy the code it needs to execute when
190 * overwriting the kernel text. This function generates a new set of page
191 * tables, which it loads into ttbr0.
192 *
193 * Length is provided as we probably only want 4K of data, even on a 64K
194 * page system.
195 */
196 static int create_safe_exec_page(void *src_start, size_t length,
197 unsigned long dst_addr,
198 phys_addr_t *phys_dst_addr)
199 {
200 struct trans_pgd_info trans_info = {
201 .trans_alloc_page = hibernate_page_alloc,
> 202 .trans_alloc_arg = (void *)GFP_ATOMIC,
203 };
204
205 void *page = (void *)get_safe_page(GFP_ATOMIC);
206 pgd_t *trans_pgd;
207 int rc;
208
209 if (!page)
210 return -ENOMEM;
211
212 memcpy(page, src_start, length);
213 __flush_icache_range((unsigned long)page, (unsigned long)page + length);
214
215 trans_pgd = (void *)get_safe_page(GFP_ATOMIC);
216 if (!trans_pgd)
217 return -ENOMEM;
218
219 rc = trans_pgd_map_page(&trans_info, trans_pgd, page, dst_addr,
220 PAGE_KERNEL_EXEC);
221 if (rc)
222 return rc;
223
224 /*
225 * Load our new page tables. A strict BBM approach requires that we
226 * ensure that TLBs are free of any entries that may overlap with the
227 * global mappings we are about to install.
228 *
229 * For a real hibernate/resume cycle TTBR0 currently points to a zero
230 * page, but TLBs may contain stale ASID-tagged entries (e.g. for EFI
231 * runtime services), while for a userspace-driven test_resume cycle it
232 * points to userspace page tables (and we must point it at a zero page
233 * ourselves). Elsewhere we only (un)install the idmap with preemption
234 * disabled, so T0SZ should be as required regardless.
235 */
236 cpu_set_reserved_ttbr0();
237 local_flush_tlb_all();
238 write_sysreg(phys_to_ttbr(virt_to_phys(trans_pgd)), ttbr0_el1);
239 isb();
240
241 *phys_dst_addr = virt_to_phys(page);
242
243 return 0;
244 }
245

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@xxxxxxxxxxxx

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