linux-kernel - arch/arm64/kernel/hibernate.c:202:44: sparse: sparse: cast from restricted gfp

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Message-ID: <202203120653.S3Am11od-lkp@intel.com>
Date:   Sat, 12 Mar 2022 06:54:50 +0800
From:   kernel test robot <lkp@...el.com>
To:     Pavel Tatashin <pasha.tatashin@...een.com>
Cc:     kbuild-all@...ts.01.org, linux-kernel@...r.kernel.org,
        Will Deacon <will@...nel.org>,
        Matthias Brugger <mbrugger@...e.com>
Subject: arch/arm64/kernel/hibernate.c:202:44: sparse: sparse: cast from
 restricted gfp_t

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head:   68453767131a5deec1e8f9ac92a9042f929e585d
commit: 50f53fb721817a6efa541cca24f1b7caa84801c1 arm64: trans_pgd: make trans_pgd_map_page generic
date:   1 year, 1 month ago
config: arm64-allmodconfig (https://download.01.org/0day-ci/archive/20220312/202203120653.S3Am11od-lkp@intel.com/config)
compiler: aarch64-linux-gcc (GCC) 11.2.0
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: v0.6.4-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 config file to linux build tree
        mkdir build_dir
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.2.0 make.cross C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__' O=build_dir ARCH=arm64 SHELL=/bin/bash arch/arm64/kernel/

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


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	

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