diff mbox series

[2/5] mm: Introduce pudp/p4dp/pgdp_get() functions

Message ID 20231002151031.110551-3-alexghiti@rivosinc.com
State New
Headers show
Series riscv: Use READ_ONCE()/WRITE_ONCE() for pte accesses | expand

Commit Message

Alexandre Ghiti Oct. 2, 2023, 3:10 p.m. UTC 
Instead of directly dereferencing page tables entries, which can cause
issues (see commit 20a004e7b017 ("arm64: mm: Use READ_ONCE/WRITE_ONCE when
accessing page tables"), let's introduce new functions to get the
pud/p4d/pgd entries (the pte and pmd versions already exist).

Those new functions will be used in subsequent commits by the riscv
architecture.

Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
---
 include/linux/pgtable.h | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

Comments

kernel test robot Oct. 3, 2023, 6:25 a.m. UTC | #1 
Hi Alexandre,

kernel test robot noticed the following build errors:

[auto build test ERROR on linus/master]
[also build test ERROR on v6.6-rc4 next-20231003]
[cannot apply to efi/next]
[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/Alexandre-Ghiti/riscv-Use-WRITE_ONCE-when-setting-page-table-entries/20231002-231725
base:   linus/master
patch link:    https://lore.kernel.org/r/20231002151031.110551-3-alexghiti%40rivosinc.com
patch subject: [PATCH 2/5] mm: Introduce pudp/p4dp/pgdp_get() functions
config: arm-allyesconfig (https://download.01.org/0day-ci/archive/20231003/202310031431.NkMgiRBL-lkp@intel.com/config)
compiler: arm-linux-gnueabi-gcc (GCC) 13.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20231003/202310031431.NkMgiRBL-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202310031431.NkMgiRBL-lkp@intel.com/

All error/warnings (new ones prefixed by >>):

   In file included from include/linux/mm.h:29,
                    from arch/arm/kernel/asm-offsets.c:12:
>> include/linux/pgtable.h:310:21: error: 'pgdp_get' declared as function returning an array
     310 | static inline pgd_t pgdp_get(pgd_t *pgdp)
         |                     ^~~~~~~~
   In file included from ./arch/arm/include/generated/asm/rwonce.h:1,
                    from include/linux/compiler.h:246,
                    from arch/arm/kernel/asm-offsets.c:10:
   include/linux/pgtable.h: In function 'pgdp_get':
>> include/asm-generic/rwonce.h:48:2: warning: returning 'const volatile pmdval_t *' {aka 'const volatile unsigned int *'} from a function with return type 'int' makes integer from pointer without a cast [-Wint-conversion]
      48 | ({                                                                      \
         | ~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
      49 |         compiletime_assert_rwonce_type(x);                              \
         |         ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
      50 |         __READ_ONCE(x);                                                 \
         |         ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
      51 | })
         | ~~
   include/linux/pgtable.h:312:16: note: in expansion of macro 'READ_ONCE'
     312 |         return READ_ONCE(*pgdp);
         |                ^~~~~~~~~
   make[3]: *** [scripts/Makefile.build:116: arch/arm/kernel/asm-offsets.s] Error 1
   make[3]: Target 'prepare' not remade because of errors.
   make[2]: *** [Makefile:1202: prepare0] Error 2
   make[2]: Target 'prepare' not remade because of errors.
   make[1]: *** [Makefile:234: __sub-make] Error 2
   make[1]: Target 'prepare' not remade because of errors.
   make: *** [Makefile:234: __sub-make] Error 2
   make: Target 'prepare' not remade because of errors.


vim +/pgdp_get +310 include/linux/pgtable.h

   308	
   309	#ifndef pgdp_get
 > 310	static inline pgd_t pgdp_get(pgd_t *pgdp)
   311	{
   312		return READ_ONCE(*pgdp);
   313	}
   314	#endif
   315
kernel test robot Oct. 3, 2023, 7:52 a.m. UTC | #2 
Hi Alexandre,

kernel test robot noticed the following build errors:

[auto build test ERROR on linus/master]
[also build test ERROR on v6.6-rc4 next-20231003]
[cannot apply to efi/next]
[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/Alexandre-Ghiti/riscv-Use-WRITE_ONCE-when-setting-page-table-entries/20231002-231725
base:   linus/master
patch link:    https://lore.kernel.org/r/20231002151031.110551-3-alexghiti%40rivosinc.com
patch subject: [PATCH 2/5] mm: Introduce pudp/p4dp/pgdp_get() functions
config: arm-moxart_defconfig (https://download.01.org/0day-ci/archive/20231003/202310031548.53wZmUUH-lkp@intel.com/config)
compiler: clang version 17.0.0 (https://github.com/llvm/llvm-project.git 4a5ac14ee968ff0ad5d2cc1ffa0299048db4c88a)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20231003/202310031548.53wZmUUH-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202310031548.53wZmUUH-lkp@intel.com/

All errors (new ones prefixed by >>):

   In file included from arch/arm/kernel/asm-offsets.c:12:
   In file included from include/linux/mm.h:29:
>> include/linux/pgtable.h:310:29: error: function cannot return array type 'pgd_t' (aka 'unsigned int[2]')
     310 | static inline pgd_t pgdp_get(pgd_t *pgdp)
         |                             ^
>> include/linux/pgtable.h:312:9: error: incompatible pointer to integer conversion returning 'const volatile pmdval_t *' (aka 'const volatile unsigned int *') from a function with result type 'int' [-Wint-conversion]
     312 |         return READ_ONCE(*pgdp);
         |                ^~~~~~~~~~~~~~~~
   include/asm-generic/rwonce.h:47:28: note: expanded from macro 'READ_ONCE'
      47 | #define READ_ONCE(x)                                                    \
         |                                                                         ^
      48 | ({                                                                      \
         | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
      49 |         compiletime_assert_rwonce_type(x);                              \
         |         ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
      50 |         __READ_ONCE(x);                                                 \
         |         ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
      51 | })
         | ~~
   In file included from arch/arm/kernel/asm-offsets.c:12:
   In file included from include/linux/mm.h:1075:
   In file included from include/linux/huge_mm.h:8:
   In file included from include/linux/fs.h:33:
   In file included from include/linux/percpu-rwsem.h:7:
   In file included from include/linux/rcuwait.h:6:
   In file included from include/linux/sched/signal.h:6:
   include/linux/signal.h:97:11: warning: array index 3 is past the end of the array (that has type 'unsigned long[2]') [-Warray-bounds]
      97 |                 return (set->sig[3] | set->sig[2] |
         |                         ^        ~
   arch/arm/include/asm/signal.h:17:2: note: array 'sig' declared here
      17 |         unsigned long sig[_NSIG_WORDS];
         |         ^
   In file included from arch/arm/kernel/asm-offsets.c:12:
   In file included from include/linux/mm.h:1075:
   In file included from include/linux/huge_mm.h:8:
   In file included from include/linux/fs.h:33:
   In file included from include/linux/percpu-rwsem.h:7:
   In file included from include/linux/rcuwait.h:6:
   In file included from include/linux/sched/signal.h:6:
   include/linux/signal.h:97:25: warning: array index 2 is past the end of the array (that has type 'unsigned long[2]') [-Warray-bounds]
      97 |                 return (set->sig[3] | set->sig[2] |
         |                                       ^        ~
   arch/arm/include/asm/signal.h:17:2: note: array 'sig' declared here
      17 |         unsigned long sig[_NSIG_WORDS];
         |         ^
   In file included from arch/arm/kernel/asm-offsets.c:12:
   In file included from include/linux/mm.h:1075:
   In file included from include/linux/huge_mm.h:8:
   In file included from include/linux/fs.h:33:
   In file included from include/linux/percpu-rwsem.h:7:
   In file included from include/linux/rcuwait.h:6:
   In file included from include/linux/sched/signal.h:6:
   include/linux/signal.h:113:11: warning: array index 3 is past the end of the array (that has type 'const unsigned long[2]') [-Warray-bounds]
     113 |                 return  (set1->sig[3] == set2->sig[3]) &&
         |                          ^         ~
   arch/arm/include/asm/signal.h:17:2: note: array 'sig' declared here
      17 |         unsigned long sig[_NSIG_WORDS];
         |         ^
   In file included from arch/arm/kernel/asm-offsets.c:12:
   In file included from include/linux/mm.h:1075:
   In file included from include/linux/huge_mm.h:8:
   In file included from include/linux/fs.h:33:
   In file included from include/linux/percpu-rwsem.h:7:
   In file included from include/linux/rcuwait.h:6:
   In file included from include/linux/sched/signal.h:6:
   include/linux/signal.h:113:27: warning: array index 3 is past the end of the array (that has type 'const unsigned long[2]') [-Warray-bounds]
     113 |                 return  (set1->sig[3] == set2->sig[3]) &&
         |                                          ^         ~
   arch/arm/include/asm/signal.h:17:2: note: array 'sig' declared here
      17 |         unsigned long sig[_NSIG_WORDS];
         |         ^
   In file included from arch/arm/kernel/asm-offsets.c:12:
   In file included from include/linux/mm.h:1075:
   In file included from include/linux/huge_mm.h:8:
   In file included from include/linux/fs.h:33:
   In file included from include/linux/percpu-rwsem.h:7:
   In file included from include/linux/rcuwait.h:6:
   In file included from include/linux/sched/signal.h:6:
   include/linux/signal.h:114:5: warning: array index 2 is past the end of the array (that has type 'const unsigned long[2]') [-Warray-bounds]
     114 |                         (set1->sig[2] == set2->sig[2]) &&
         |                          ^         ~
   arch/arm/include/asm/signal.h:17:2: note: array 'sig' declared here
      17 |         unsigned long sig[_NSIG_WORDS];
         |         ^
   In file included from arch/arm/kernel/asm-offsets.c:12:
   In file included from include/linux/mm.h:1075:
   In file included from include/linux/huge_mm.h:8:
   In file included from include/linux/fs.h:33:
   In file included from include/linux/percpu-rwsem.h:7:
   In file included from include/linux/rcuwait.h:6:
   In file included from include/linux/sched/signal.h:6:
   include/linux/signal.h:114:21: warning: array index 2 is past the end of the array (that has type 'const unsigned long[2]') [-Warray-bounds]
     114 |                         (set1->sig[2] == set2->sig[2]) &&
         |                                          ^         ~
   arch/arm/include/asm/signal.h:17:2: note: array 'sig' declared here
      17 |         unsigned long sig[_NSIG_WORDS];
         |         ^
   In file included from arch/arm/kernel/asm-offsets.c:12:
   In file included from include/linux/mm.h:1075:
   In file included from include/linux/huge_mm.h:8:
   In file included from include/linux/fs.h:33:
   In file included from include/linux/percpu-rwsem.h:7:
   In file included from include/linux/rcuwait.h:6:
   In file included from include/linux/sched/signal.h:6:
   include/linux/signal.h:156:1: warning: array index 3 is past the end of the array (that has type 'const unsigned long[2]') [-Warray-bounds]
     156 | _SIG_SET_BINOP(sigorsets, _sig_or)


vim +310 include/linux/pgtable.h

   308	
   309	#ifndef pgdp_get
 > 310	static inline pgd_t pgdp_get(pgd_t *pgdp)
   311	{
 > 312		return READ_ONCE(*pgdp);
   313	}
   314	#endif
   315
diff mbox series

Patch

diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h
index 1fba072b3dac..4ce68bcc201d 100644
--- a/include/linux/pgtable.h
+++ b/include/linux/pgtable.h
@@ -284,6 +284,27 @@  static inline pmd_t pmdp_get(pmd_t *pmdp)
 }
 #endif
 
+#ifndef pudp_get
+static inline pud_t pudp_get(pud_t *pudp)
+{
+	return READ_ONCE(*pudp);
+}
+#endif
+
+#ifndef p4dp_get
+static inline p4d_t p4dp_get(p4d_t *p4dp)
+{
+	return READ_ONCE(*p4dp);
+}
+#endif
+
+#ifndef pgdp_get
+static inline pgd_t pgdp_get(pgd_t *pgdp)
+{
+	return READ_ONCE(*pgdp);
+}
+#endif
+
 #ifndef __HAVE_ARCH_PTEP_TEST_AND_CLEAR_YOUNG
 static inline int ptep_test_and_clear_young(struct vm_area_struct *vma,
 					    unsigned long address,