diff mbox series

highmem: Fix kmap_to_page() for kmap_local_page() addresses

Message ID 20221003040427.1082050-1-ira.weiny@intel.com (mailing list archive)
State New
Headers show
Series highmem: Fix kmap_to_page() for kmap_local_page() addresses | expand

Commit Message

Ira Weiny Oct. 3, 2022, 4:04 a.m. UTC 
From: Ira Weiny <ira.weiny@intel.com>

kmap_to_page() is used to get the page for a virtual address which may
be kmap'ed.  Unfortunately, kmap_local_page() stores mappings in a
thread local array separate from kmap().  These mappings were not
checked by the call.

Check the kmap_local_page() mappings and return the page if found.

Because it is intended to remove kmap_to_page() add a warn on once to
the kmap checks to flag potential issues early.

Cc: "Fabio M. De Francesco" <fmdefrancesco@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Reported-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Ira Weiny <ira.weiny@intel.com>

---
I'm still working toward getting rid of kmap_to_page.[1]  But until then
this fix should be applied.

[1] https://lore.kernel.org/linux-mm/20221002002326.946620-1-ira.weiny@intel.com/
---
 mm/highmem.c | 40 ++++++++++++++++++++++++++++++----------
 1 file changed, 30 insertions(+), 10 deletions(-)


base-commit: 274d7803837da78dfc911bcda0d593412676fc20

Comments

kernel test robot Oct. 3, 2022, 7:23 a.m. UTC | #1 
Hi,

I love your patch! Yet something to improve:

[auto build test ERROR on 274d7803837da78dfc911bcda0d593412676fc20]

url:    https://github.com/intel-lab-lkp/linux/commits/ira-weiny-intel-com/highmem-Fix-kmap_to_page-for-kmap_local_page-addresses/20221003-120524
base:   274d7803837da78dfc911bcda0d593412676fc20
config: i386-tinyconfig
compiler: gcc-11 (Debian 11.3.0-5) 11.3.0
reproduce (this is a W=1 build):
        # https://github.com/intel-lab-lkp/linux/commit/cd2106b2845310f5ee6e1a754c09e7caeabf3e01
        git remote add linux-review https://github.com/intel-lab-lkp/linux
        git fetch --no-tags linux-review ira-weiny-intel-com/highmem-Fix-kmap_to_page-for-kmap_local_page-addresses/20221003-120524
        git checkout cd2106b2845310f5ee6e1a754c09e7caeabf3e01
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        make W=1 O=build_dir ARCH=i386 SHELL=/bin/bash

If you fix the issue, kindly add following tag where applicable
| Reported-by: kernel test robot <lkp@intel.com>

All errors (new ones prefixed by >>):

   mm/highmem.c: In function '__kmap_local_pfn_prot':
>> mm/highmem.c:549:15: error: implicit declaration of function 'arch_kmap_local_map_idx'; did you mean 'arch_kmap_local_unmap_idx'? [-Werror=implicit-function-declaration]
     549 |         idx = arch_kmap_local_map_idx(kmap_local_idx_push(), pfn);
         |               ^~~~~~~~~~~~~~~~~~~~~~~
         |               arch_kmap_local_unmap_idx
   mm/highmem.c: In function 'kunmap_local_indexed':
>> mm/highmem.c:495:49: error: implicit declaration of function 'kmap_local_calc_idx'; did you mean 'kmap_local_idx'? [-Werror=implicit-function-declaration]
     495 | #define arch_kmap_local_unmap_idx(idx, vaddr)   kmap_local_calc_idx(idx)
         |                                                 ^~~~~~~~~~~~~~~~~~~
   mm/highmem.c:609:15: note: in expansion of macro 'arch_kmap_local_unmap_idx'
     609 |         idx = arch_kmap_local_unmap_idx(kmap_local_idx(), addr);
         |               ^~~~~~~~~~~~~~~~~~~~~~~~~
   cc1: some warnings being treated as errors


vim +549 mm/highmem.c

298fa1ad5571f5 Thomas Gleixner 2020-11-03  493  
298fa1ad5571f5 Thomas Gleixner 2020-11-03  494  #ifndef arch_kmap_local_unmap_idx
298fa1ad5571f5 Thomas Gleixner 2020-11-03 @495  #define arch_kmap_local_unmap_idx(idx, vaddr)	kmap_local_calc_idx(idx)
298fa1ad5571f5 Thomas Gleixner 2020-11-03  496  #endif
298fa1ad5571f5 Thomas Gleixner 2020-11-03  497  
298fa1ad5571f5 Thomas Gleixner 2020-11-03  498  #ifndef arch_kmap_local_high_get
298fa1ad5571f5 Thomas Gleixner 2020-11-03  499  static inline void *arch_kmap_local_high_get(struct page *page)
298fa1ad5571f5 Thomas Gleixner 2020-11-03  500  {
298fa1ad5571f5 Thomas Gleixner 2020-11-03  501  	return NULL;
298fa1ad5571f5 Thomas Gleixner 2020-11-03  502  }
298fa1ad5571f5 Thomas Gleixner 2020-11-03  503  #endif
298fa1ad5571f5 Thomas Gleixner 2020-11-03  504  
a1dce7fd2ade8e Thomas Gleixner 2021-01-23  505  #ifndef arch_kmap_local_set_pte
a1dce7fd2ade8e Thomas Gleixner 2021-01-23  506  #define arch_kmap_local_set_pte(mm, vaddr, ptep, ptev)	\
a1dce7fd2ade8e Thomas Gleixner 2021-01-23  507  	set_pte_at(mm, vaddr, ptep, ptev)
a1dce7fd2ade8e Thomas Gleixner 2021-01-23  508  #endif
a1dce7fd2ade8e Thomas Gleixner 2021-01-23  509  
298fa1ad5571f5 Thomas Gleixner 2020-11-03  510  /* Unmap a local mapping which was obtained by kmap_high_get() */
2a656cad337e0e Thomas Gleixner 2020-11-12  511  static inline bool kmap_high_unmap_local(unsigned long vaddr)
298fa1ad5571f5 Thomas Gleixner 2020-11-03  512  {
298fa1ad5571f5 Thomas Gleixner 2020-11-03  513  #ifdef ARCH_NEEDS_KMAP_HIGH_GET
2a656cad337e0e Thomas Gleixner 2020-11-12  514  	if (vaddr >= PKMAP_ADDR(0) && vaddr < PKMAP_ADDR(LAST_PKMAP)) {
298fa1ad5571f5 Thomas Gleixner 2020-11-03  515  		kunmap_high(pte_page(pkmap_page_table[PKMAP_NR(vaddr)]));
2a656cad337e0e Thomas Gleixner 2020-11-12  516  		return true;
2a656cad337e0e Thomas Gleixner 2020-11-12  517  	}
298fa1ad5571f5 Thomas Gleixner 2020-11-03  518  #endif
2a656cad337e0e Thomas Gleixner 2020-11-12  519  	return false;
298fa1ad5571f5 Thomas Gleixner 2020-11-03  520  }
298fa1ad5571f5 Thomas Gleixner 2020-11-03  521  
298fa1ad5571f5 Thomas Gleixner 2020-11-03  522  static pte_t *__kmap_pte;
298fa1ad5571f5 Thomas Gleixner 2020-11-03  523  
825c43f50e3aa8 Ard Biesheuvel  2021-11-19  524  static pte_t *kmap_get_pte(unsigned long vaddr, int idx)
298fa1ad5571f5 Thomas Gleixner 2020-11-03  525  {
825c43f50e3aa8 Ard Biesheuvel  2021-11-19  526  	if (IS_ENABLED(CONFIG_KMAP_LOCAL_NON_LINEAR_PTE_ARRAY))
825c43f50e3aa8 Ard Biesheuvel  2021-11-19  527  		/*
825c43f50e3aa8 Ard Biesheuvel  2021-11-19  528  		 * Set by the arch if __kmap_pte[-idx] does not produce
825c43f50e3aa8 Ard Biesheuvel  2021-11-19  529  		 * the correct entry.
825c43f50e3aa8 Ard Biesheuvel  2021-11-19  530  		 */
825c43f50e3aa8 Ard Biesheuvel  2021-11-19  531  		return virt_to_kpte(vaddr);
298fa1ad5571f5 Thomas Gleixner 2020-11-03  532  	if (!__kmap_pte)
298fa1ad5571f5 Thomas Gleixner 2020-11-03  533  		__kmap_pte = virt_to_kpte(__fix_to_virt(FIX_KMAP_BEGIN));
825c43f50e3aa8 Ard Biesheuvel  2021-11-19  534  	return &__kmap_pte[-idx];
298fa1ad5571f5 Thomas Gleixner 2020-11-03  535  }
298fa1ad5571f5 Thomas Gleixner 2020-11-03  536  
298fa1ad5571f5 Thomas Gleixner 2020-11-03  537  void *__kmap_local_pfn_prot(unsigned long pfn, pgprot_t prot)
298fa1ad5571f5 Thomas Gleixner 2020-11-03  538  {
825c43f50e3aa8 Ard Biesheuvel  2021-11-19  539  	pte_t pteval, *kmap_pte;
298fa1ad5571f5 Thomas Gleixner 2020-11-03  540  	unsigned long vaddr;
298fa1ad5571f5 Thomas Gleixner 2020-11-03  541  	int idx;
298fa1ad5571f5 Thomas Gleixner 2020-11-03  542  
f3ba3c710ac5a3 Thomas Gleixner 2020-11-18  543  	/*
f3ba3c710ac5a3 Thomas Gleixner 2020-11-18  544  	 * Disable migration so resulting virtual address is stable
f0953a1bbaca71 Ingo Molnar     2021-05-06  545  	 * across preemption.
f3ba3c710ac5a3 Thomas Gleixner 2020-11-18  546  	 */
f3ba3c710ac5a3 Thomas Gleixner 2020-11-18  547  	migrate_disable();
298fa1ad5571f5 Thomas Gleixner 2020-11-03  548  	preempt_disable();
298fa1ad5571f5 Thomas Gleixner 2020-11-03 @549  	idx = arch_kmap_local_map_idx(kmap_local_idx_push(), pfn);
298fa1ad5571f5 Thomas Gleixner 2020-11-03  550  	vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
825c43f50e3aa8 Ard Biesheuvel  2021-11-19  551  	kmap_pte = kmap_get_pte(vaddr, idx);
825c43f50e3aa8 Ard Biesheuvel  2021-11-19  552  	BUG_ON(!pte_none(*kmap_pte));
298fa1ad5571f5 Thomas Gleixner 2020-11-03  553  	pteval = pfn_pte(pfn, prot);
825c43f50e3aa8 Ard Biesheuvel  2021-11-19  554  	arch_kmap_local_set_pte(&init_mm, vaddr, kmap_pte, pteval);
298fa1ad5571f5 Thomas Gleixner 2020-11-03  555  	arch_kmap_local_post_map(vaddr, pteval);
5fbda3ecd14a53 Thomas Gleixner 2020-11-18  556  	current->kmap_ctrl.pteval[kmap_local_idx()] = pteval;
298fa1ad5571f5 Thomas Gleixner 2020-11-03  557  	preempt_enable();
298fa1ad5571f5 Thomas Gleixner 2020-11-03  558  
298fa1ad5571f5 Thomas Gleixner 2020-11-03  559  	return (void *)vaddr;
298fa1ad5571f5 Thomas Gleixner 2020-11-03  560  }
298fa1ad5571f5 Thomas Gleixner 2020-11-03  561  EXPORT_SYMBOL_GPL(__kmap_local_pfn_prot);
298fa1ad5571f5 Thomas Gleixner 2020-11-03  562
kernel test robot Oct. 3, 2022, 12:51 p.m. UTC | #2 
Hi,

I love your patch! Yet something to improve:

[auto build test ERROR on 274d7803837da78dfc911bcda0d593412676fc20]

url:    https://github.com/intel-lab-lkp/linux/commits/ira-weiny-intel-com/highmem-Fix-kmap_to_page-for-kmap_local_page-addresses/20221003-120524
base:   274d7803837da78dfc911bcda0d593412676fc20
config: x86_64-randconfig-a003-20221003
compiler: clang version 14.0.6 (https://github.com/llvm/llvm-project f28c006a5895fc0e329fe15fead81e37457cb1d1)
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/intel-lab-lkp/linux/commit/cd2106b2845310f5ee6e1a754c09e7caeabf3e01
        git remote add linux-review https://github.com/intel-lab-lkp/linux
        git fetch --no-tags linux-review ira-weiny-intel-com/highmem-Fix-kmap_to_page-for-kmap_local_page-addresses/20221003-120524
        git checkout cd2106b2845310f5ee6e1a754c09e7caeabf3e01
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=x86_64 SHELL=/bin/bash

If you fix the issue, kindly add following tag where applicable
| Reported-by: kernel test robot <lkp@intel.com>

All errors (new ones prefixed by >>):

>> mm/highmem.c:549:8: error: implicit declaration of function 'arch_kmap_local_map_idx' is invalid in C99 [-Werror,-Wimplicit-function-declaration]
           idx = arch_kmap_local_map_idx(kmap_local_idx_push(), pfn);
                 ^
   mm/highmem.c:549:8: note: did you mean 'arch_kmap_local_high_get'?
   mm/highmem.c:499:21: note: 'arch_kmap_local_high_get' declared here
   static inline void *arch_kmap_local_high_get(struct page *page)
                       ^
>> mm/highmem.c:609:8: error: implicit declaration of function 'kmap_local_calc_idx' is invalid in C99 [-Werror,-Wimplicit-function-declaration]
           idx = arch_kmap_local_unmap_idx(kmap_local_idx(), addr);
                 ^
   mm/highmem.c:495:47: note: expanded from macro 'arch_kmap_local_unmap_idx'
   #define arch_kmap_local_unmap_idx(idx, vaddr)   kmap_local_calc_idx(idx)
                                                   ^
   mm/highmem.c:609:8: note: did you mean 'kmap_local_idx'?
   mm/highmem.c:495:47: note: expanded from macro 'arch_kmap_local_unmap_idx'
   #define arch_kmap_local_unmap_idx(idx, vaddr)   kmap_local_calc_idx(idx)
                                                   ^
   mm/highmem.c:471:19: note: 'kmap_local_idx' declared here
   static inline int kmap_local_idx(void)
                     ^
   mm/highmem.c:660:9: error: implicit declaration of function 'arch_kmap_local_map_idx' is invalid in C99 [-Werror,-Wimplicit-function-declaration]
                   idx = arch_kmap_local_map_idx(i, pte_pfn(pteval));
                         ^
   mm/highmem.c:691:9: error: implicit declaration of function 'arch_kmap_local_map_idx' is invalid in C99 [-Werror,-Wimplicit-function-declaration]
                   idx = arch_kmap_local_map_idx(i, pte_pfn(pteval));
                         ^
   4 errors generated.


vim +/arch_kmap_local_map_idx +549 mm/highmem.c

298fa1ad5571f5 Thomas Gleixner       2020-11-03  536  
298fa1ad5571f5 Thomas Gleixner       2020-11-03  537  void *__kmap_local_pfn_prot(unsigned long pfn, pgprot_t prot)
298fa1ad5571f5 Thomas Gleixner       2020-11-03  538  {
825c43f50e3aa8 Ard Biesheuvel        2021-11-19  539  	pte_t pteval, *kmap_pte;
298fa1ad5571f5 Thomas Gleixner       2020-11-03  540  	unsigned long vaddr;
298fa1ad5571f5 Thomas Gleixner       2020-11-03  541  	int idx;
298fa1ad5571f5 Thomas Gleixner       2020-11-03  542  
f3ba3c710ac5a3 Thomas Gleixner       2020-11-18  543  	/*
f3ba3c710ac5a3 Thomas Gleixner       2020-11-18  544  	 * Disable migration so resulting virtual address is stable
f0953a1bbaca71 Ingo Molnar           2021-05-06  545  	 * across preemption.
f3ba3c710ac5a3 Thomas Gleixner       2020-11-18  546  	 */
f3ba3c710ac5a3 Thomas Gleixner       2020-11-18  547  	migrate_disable();
298fa1ad5571f5 Thomas Gleixner       2020-11-03  548  	preempt_disable();
298fa1ad5571f5 Thomas Gleixner       2020-11-03 @549  	idx = arch_kmap_local_map_idx(kmap_local_idx_push(), pfn);
298fa1ad5571f5 Thomas Gleixner       2020-11-03  550  	vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
825c43f50e3aa8 Ard Biesheuvel        2021-11-19  551  	kmap_pte = kmap_get_pte(vaddr, idx);
825c43f50e3aa8 Ard Biesheuvel        2021-11-19  552  	BUG_ON(!pte_none(*kmap_pte));
298fa1ad5571f5 Thomas Gleixner       2020-11-03  553  	pteval = pfn_pte(pfn, prot);
825c43f50e3aa8 Ard Biesheuvel        2021-11-19  554  	arch_kmap_local_set_pte(&init_mm, vaddr, kmap_pte, pteval);
298fa1ad5571f5 Thomas Gleixner       2020-11-03  555  	arch_kmap_local_post_map(vaddr, pteval);
5fbda3ecd14a53 Thomas Gleixner       2020-11-18  556  	current->kmap_ctrl.pteval[kmap_local_idx()] = pteval;
298fa1ad5571f5 Thomas Gleixner       2020-11-03  557  	preempt_enable();
298fa1ad5571f5 Thomas Gleixner       2020-11-03  558  
298fa1ad5571f5 Thomas Gleixner       2020-11-03  559  	return (void *)vaddr;
298fa1ad5571f5 Thomas Gleixner       2020-11-03  560  }
298fa1ad5571f5 Thomas Gleixner       2020-11-03  561  EXPORT_SYMBOL_GPL(__kmap_local_pfn_prot);
298fa1ad5571f5 Thomas Gleixner       2020-11-03  562  
298fa1ad5571f5 Thomas Gleixner       2020-11-03  563  void *__kmap_local_page_prot(struct page *page, pgprot_t prot)
298fa1ad5571f5 Thomas Gleixner       2020-11-03  564  {
298fa1ad5571f5 Thomas Gleixner       2020-11-03  565  	void *kmap;
298fa1ad5571f5 Thomas Gleixner       2020-11-03  566  
0e91a0c6984c83 Thomas Gleixner       2020-11-18  567  	/*
0e91a0c6984c83 Thomas Gleixner       2020-11-18  568  	 * To broaden the usage of the actual kmap_local() machinery always map
0e91a0c6984c83 Thomas Gleixner       2020-11-18  569  	 * pages when debugging is enabled and the architecture has no problems
0e91a0c6984c83 Thomas Gleixner       2020-11-18  570  	 * with alias mappings.
0e91a0c6984c83 Thomas Gleixner       2020-11-18  571  	 */
0e91a0c6984c83 Thomas Gleixner       2020-11-18  572  	if (!IS_ENABLED(CONFIG_DEBUG_KMAP_LOCAL_FORCE_MAP) && !PageHighMem(page))
298fa1ad5571f5 Thomas Gleixner       2020-11-03  573  		return page_address(page);
298fa1ad5571f5 Thomas Gleixner       2020-11-03  574  
298fa1ad5571f5 Thomas Gleixner       2020-11-03  575  	/* Try kmap_high_get() if architecture has it enabled */
298fa1ad5571f5 Thomas Gleixner       2020-11-03  576  	kmap = arch_kmap_local_high_get(page);
298fa1ad5571f5 Thomas Gleixner       2020-11-03  577  	if (kmap)
298fa1ad5571f5 Thomas Gleixner       2020-11-03  578  		return kmap;
298fa1ad5571f5 Thomas Gleixner       2020-11-03  579  
298fa1ad5571f5 Thomas Gleixner       2020-11-03  580  	return __kmap_local_pfn_prot(page_to_pfn(page), prot);
298fa1ad5571f5 Thomas Gleixner       2020-11-03  581  }
298fa1ad5571f5 Thomas Gleixner       2020-11-03  582  EXPORT_SYMBOL(__kmap_local_page_prot);
298fa1ad5571f5 Thomas Gleixner       2020-11-03  583  
39ade048a32ea6 Fabio M. De Francesco 2022-07-06  584  void kunmap_local_indexed(const void *vaddr)
298fa1ad5571f5 Thomas Gleixner       2020-11-03  585  {
298fa1ad5571f5 Thomas Gleixner       2020-11-03  586  	unsigned long addr = (unsigned long) vaddr & PAGE_MASK;
825c43f50e3aa8 Ard Biesheuvel        2021-11-19  587  	pte_t *kmap_pte;
298fa1ad5571f5 Thomas Gleixner       2020-11-03  588  	int idx;
298fa1ad5571f5 Thomas Gleixner       2020-11-03  589  
298fa1ad5571f5 Thomas Gleixner       2020-11-03  590  	if (addr < __fix_to_virt(FIX_KMAP_END) ||
298fa1ad5571f5 Thomas Gleixner       2020-11-03  591  	    addr > __fix_to_virt(FIX_KMAP_BEGIN)) {
0e91a0c6984c83 Thomas Gleixner       2020-11-18  592  		if (IS_ENABLED(CONFIG_DEBUG_KMAP_LOCAL_FORCE_MAP)) {
0e91a0c6984c83 Thomas Gleixner       2020-11-18  593  			/* This _should_ never happen! See above. */
0e91a0c6984c83 Thomas Gleixner       2020-11-18  594  			WARN_ON_ONCE(1);
0e91a0c6984c83 Thomas Gleixner       2020-11-18  595  			return;
0e91a0c6984c83 Thomas Gleixner       2020-11-18  596  		}
2a656cad337e0e Thomas Gleixner       2020-11-12  597  		/*
2a656cad337e0e Thomas Gleixner       2020-11-12  598  		 * Handle mappings which were obtained by kmap_high_get()
2a656cad337e0e Thomas Gleixner       2020-11-12  599  		 * first as the virtual address of such mappings is below
2a656cad337e0e Thomas Gleixner       2020-11-12  600  		 * PAGE_OFFSET. Warn for all other addresses which are in
2a656cad337e0e Thomas Gleixner       2020-11-12  601  		 * the user space part of the virtual address space.
2a656cad337e0e Thomas Gleixner       2020-11-12  602  		 */
2a656cad337e0e Thomas Gleixner       2020-11-12  603  		if (!kmap_high_unmap_local(addr))
298fa1ad5571f5 Thomas Gleixner       2020-11-03  604  			WARN_ON_ONCE(addr < PAGE_OFFSET);
298fa1ad5571f5 Thomas Gleixner       2020-11-03  605  		return;
298fa1ad5571f5 Thomas Gleixner       2020-11-03  606  	}
298fa1ad5571f5 Thomas Gleixner       2020-11-03  607  
298fa1ad5571f5 Thomas Gleixner       2020-11-03  608  	preempt_disable();
298fa1ad5571f5 Thomas Gleixner       2020-11-03 @609  	idx = arch_kmap_local_unmap_idx(kmap_local_idx(), addr);
298fa1ad5571f5 Thomas Gleixner       2020-11-03  610  	WARN_ON_ONCE(addr != __fix_to_virt(FIX_KMAP_BEGIN + idx));
298fa1ad5571f5 Thomas Gleixner       2020-11-03  611  
825c43f50e3aa8 Ard Biesheuvel        2021-11-19  612  	kmap_pte = kmap_get_pte(addr, idx);
298fa1ad5571f5 Thomas Gleixner       2020-11-03  613  	arch_kmap_local_pre_unmap(addr);
825c43f50e3aa8 Ard Biesheuvel        2021-11-19  614  	pte_clear(&init_mm, addr, kmap_pte);
298fa1ad5571f5 Thomas Gleixner       2020-11-03  615  	arch_kmap_local_post_unmap(addr);
5fbda3ecd14a53 Thomas Gleixner       2020-11-18  616  	current->kmap_ctrl.pteval[kmap_local_idx()] = __pte(0);
298fa1ad5571f5 Thomas Gleixner       2020-11-03  617  	kmap_local_idx_pop();
298fa1ad5571f5 Thomas Gleixner       2020-11-03  618  	preempt_enable();
f3ba3c710ac5a3 Thomas Gleixner       2020-11-18  619  	migrate_enable();
298fa1ad5571f5 Thomas Gleixner       2020-11-03  620  }
298fa1ad5571f5 Thomas Gleixner       2020-11-03  621  EXPORT_SYMBOL(kunmap_local_indexed);
5fbda3ecd14a53 Thomas Gleixner       2020-11-18  622
diff mbox series

Patch

diff --git a/mm/highmem.c b/mm/highmem.c
index c707d7202d5f..29423c1afb3e 100644
--- a/mm/highmem.c
+++ b/mm/highmem.c
@@ -140,16 +140,45 @@  pte_t *pkmap_page_table;
 		do { spin_unlock(&kmap_lock); (void)(flags); } while (0)
 #endif
 
+static inline int kmap_local_calc_idx(int idx)
+{
+	return idx + KM_MAX_IDX * smp_processor_id();
+}
+
+#ifndef arch_kmap_local_map_idx
+#define arch_kmap_local_map_idx(idx, pfn)	kmap_local_calc_idx(idx)
+#endif
+
 struct page *__kmap_to_page(void *vaddr)
 {
+	unsigned long base = (unsigned long) vaddr & PAGE_MASK;
+	struct kmap_ctrl *kctrl = &current->kmap_ctrl;
 	unsigned long addr = (unsigned long)vaddr;
+	int i;
 
-	if (addr >= PKMAP_ADDR(0) && addr < PKMAP_ADDR(LAST_PKMAP)) {
+	/* kmap() mappings */
+	if (WARN_ON_ONCE(addr >= PKMAP_ADDR(0) &&
+			 addr < PKMAP_ADDR(LAST_PKMAP))) {
 		int i = PKMAP_NR(addr);
 
 		return pte_page(pkmap_page_table[i]);
 	}
 
+	/* kmap_local_page() mappings */
+	if (WARN_ON_ONCE(base >= __fix_to_virt(FIX_KMAP_END) &&
+			 base < __fix_to_virt(FIX_KMAP_BEGIN))) {
+		for (i = 0; i < kctrl->idx; i++) {
+			unsigned long base_addr;
+			int idx;
+
+			idx = arch_kmap_local_map_idx(i, pte_pfn(pteval));
+			base_addr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
+
+			if (base_addr == base)
+				return pte_page(kctrl->pteval[i]);
+		}
+	}
+
 	return virt_to_page(vaddr);
 }
 EXPORT_SYMBOL(__kmap_to_page);
@@ -462,10 +491,6 @@  static inline void kmap_local_idx_pop(void)
 # define arch_kmap_local_post_unmap(vaddr)		do { } while (0)
 #endif
 
-#ifndef arch_kmap_local_map_idx
-#define arch_kmap_local_map_idx(idx, pfn)	kmap_local_calc_idx(idx)
-#endif
-
 #ifndef arch_kmap_local_unmap_idx
 #define arch_kmap_local_unmap_idx(idx, vaddr)	kmap_local_calc_idx(idx)
 #endif
@@ -494,11 +519,6 @@  static inline bool kmap_high_unmap_local(unsigned long vaddr)
 	return false;
 }
 
-static inline int kmap_local_calc_idx(int idx)
-{
-	return idx + KM_MAX_IDX * smp_processor_id();
-}
-
 static pte_t *__kmap_pte;
 
 static pte_t *kmap_get_pte(unsigned long vaddr, int idx)