diff mbox series

[v2,7/8] mm/x86: Add missing pud helpers

Message ID 20240703212918.2417843-8-peterx@redhat.com (mailing list archive)
State New
Headers show
Series mm/mprotect: Fix dax puds | expand

Commit Message

Peter Xu July 3, 2024, 9:29 p.m. UTC 
These new helpers will be needed for pud entry updates soon.  Introduce
these helpers by referencing the pmd ones.  Namely:

- pudp_invalidate()
- pud_modify()

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: x86@kernel.org
Signed-off-by: Peter Xu <peterx@redhat.com>
---
 arch/x86/include/asm/pgtable.h | 55 +++++++++++++++++++++++++++++-----
 arch/x86/mm/pgtable.c          | 11 +++++++
 2 files changed, 58 insertions(+), 8 deletions(-)

Comments

kernel test robot July 6, 2024, 9:16 a.m. UTC | #1 
Hi Peter,

kernel test robot noticed the following build errors:

[auto build test ERROR on akpm-mm/mm-everything]

url:    https://github.com/intel-lab-lkp/linux/commits/Peter-Xu/mm-dax-Dump-start-address-in-fault-handler/20240705-013812
base:   https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-everything
patch link:    https://lore.kernel.org/r/20240703212918.2417843-8-peterx%40redhat.com
patch subject: [PATCH v2 7/8] mm/x86: Add missing pud helpers
config: i386-randconfig-011-20240706 (https://download.01.org/0day-ci/archive/20240706/202407061716.WH5NMiL2-lkp@intel.com/config)
compiler: gcc-11 (Ubuntu 11.4.0-4ubuntu1) 11.4.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240706/202407061716.WH5NMiL2-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/202407061716.WH5NMiL2-lkp@intel.com/

All errors (new ones prefixed by >>):

   In file included from arch/x86/include/asm/atomic.h:8,
                    from include/linux/atomic.h:7,
                    from include/linux/jump_label.h:256,
                    from include/linux/static_key.h:1,
                    from arch/x86/include/asm/nospec-branch.h:6,
                    from arch/x86/include/asm/irqflags.h:9,
                    from include/linux/irqflags.h:18,
                    from include/linux/spinlock.h:59,
                    from include/linux/mmzone.h:8,
                    from include/linux/gfp.h:7,
                    from include/linux/mm.h:7,
                    from arch/x86/mm/pgtable.c:2:
   In function 'pudp_establish',
       inlined from 'pudp_invalidate' at arch/x86/mm/pgtable.c:649:14:
>> arch/x86/include/asm/cmpxchg.h:67:25: error: call to '__xchg_wrong_size' declared with attribute error: Bad argument size for xchg
      67 |                         __ ## op ## _wrong_size();                      \
         |                         ^~~~~~~~~~~~~~~~~~~~~~~~~
   arch/x86/include/asm/cmpxchg.h:78:33: note: in expansion of macro '__xchg_op'
      78 | #define arch_xchg(ptr, v)       __xchg_op((ptr), (v), xchg, "")
         |                                 ^~~~~~~~~
   include/linux/atomic/atomic-arch-fallback.h:12:18: note: in expansion of macro 'arch_xchg'
      12 | #define raw_xchg arch_xchg
         |                  ^~~~~~~~~
   include/linux/atomic/atomic-instrumented.h:4758:9: note: in expansion of macro 'raw_xchg'
    4758 |         raw_xchg(__ai_ptr, __VA_ARGS__); \
         |         ^~~~~~~~
   arch/x86/include/asm/pgtable.h:1415:24: note: in expansion of macro 'xchg'
    1415 |                 return xchg(pudp, pud);
         |                        ^~~~


vim +/__xchg_wrong_size +67 arch/x86/include/asm/cmpxchg.h

e9826380d83d1bd Jeremy Fitzhardinge 2011-08-18  37  
e9826380d83d1bd Jeremy Fitzhardinge 2011-08-18  38  /* 
31a8394e069e47d Jeremy Fitzhardinge 2011-09-30  39   * An exchange-type operation, which takes a value and a pointer, and
7f5281ae8a8e7f8 Li Zhong            2013-04-25  40   * returns the old value.
e9826380d83d1bd Jeremy Fitzhardinge 2011-08-18  41   */
31a8394e069e47d Jeremy Fitzhardinge 2011-09-30  42  #define __xchg_op(ptr, arg, op, lock)					\
e9826380d83d1bd Jeremy Fitzhardinge 2011-08-18  43  	({								\
31a8394e069e47d Jeremy Fitzhardinge 2011-09-30  44  	        __typeof__ (*(ptr)) __ret = (arg);			\
31a8394e069e47d Jeremy Fitzhardinge 2011-09-30  45  		switch (sizeof(*(ptr))) {				\
e9826380d83d1bd Jeremy Fitzhardinge 2011-08-18  46  		case __X86_CASE_B:					\
31a8394e069e47d Jeremy Fitzhardinge 2011-09-30  47  			asm volatile (lock #op "b %b0, %1\n"		\
2ca052a3710fac2 Jeremy Fitzhardinge 2012-04-02  48  				      : "+q" (__ret), "+m" (*(ptr))	\
31a8394e069e47d Jeremy Fitzhardinge 2011-09-30  49  				      : : "memory", "cc");		\
e9826380d83d1bd Jeremy Fitzhardinge 2011-08-18  50  			break;						\
e9826380d83d1bd Jeremy Fitzhardinge 2011-08-18  51  		case __X86_CASE_W:					\
31a8394e069e47d Jeremy Fitzhardinge 2011-09-30  52  			asm volatile (lock #op "w %w0, %1\n"		\
31a8394e069e47d Jeremy Fitzhardinge 2011-09-30  53  				      : "+r" (__ret), "+m" (*(ptr))	\
31a8394e069e47d Jeremy Fitzhardinge 2011-09-30  54  				      : : "memory", "cc");		\
e9826380d83d1bd Jeremy Fitzhardinge 2011-08-18  55  			break;						\
e9826380d83d1bd Jeremy Fitzhardinge 2011-08-18  56  		case __X86_CASE_L:					\
31a8394e069e47d Jeremy Fitzhardinge 2011-09-30  57  			asm volatile (lock #op "l %0, %1\n"		\
31a8394e069e47d Jeremy Fitzhardinge 2011-09-30  58  				      : "+r" (__ret), "+m" (*(ptr))	\
31a8394e069e47d Jeremy Fitzhardinge 2011-09-30  59  				      : : "memory", "cc");		\
e9826380d83d1bd Jeremy Fitzhardinge 2011-08-18  60  			break;						\
e9826380d83d1bd Jeremy Fitzhardinge 2011-08-18  61  		case __X86_CASE_Q:					\
31a8394e069e47d Jeremy Fitzhardinge 2011-09-30  62  			asm volatile (lock #op "q %q0, %1\n"		\
31a8394e069e47d Jeremy Fitzhardinge 2011-09-30  63  				      : "+r" (__ret), "+m" (*(ptr))	\
31a8394e069e47d Jeremy Fitzhardinge 2011-09-30  64  				      : : "memory", "cc");		\
e9826380d83d1bd Jeremy Fitzhardinge 2011-08-18  65  			break;						\
e9826380d83d1bd Jeremy Fitzhardinge 2011-08-18  66  		default:						\
31a8394e069e47d Jeremy Fitzhardinge 2011-09-30 @67  			__ ## op ## _wrong_size();			\
e9826380d83d1bd Jeremy Fitzhardinge 2011-08-18  68  		}							\
31a8394e069e47d Jeremy Fitzhardinge 2011-09-30  69  		__ret;							\
e9826380d83d1bd Jeremy Fitzhardinge 2011-08-18  70  	})
e9826380d83d1bd Jeremy Fitzhardinge 2011-08-18  71
Peter Xu July 9, 2024, 7:44 p.m. UTC | #2 
On Sat, Jul 06, 2024 at 05:16:15PM +0800, kernel test robot wrote:
> Hi Peter,
> 
> kernel test robot noticed the following build errors:
> 
> [auto build test ERROR on akpm-mm/mm-everything]
> 
> url:    https://github.com/intel-lab-lkp/linux/commits/Peter-Xu/mm-dax-Dump-start-address-in-fault-handler/20240705-013812
> base:   https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-everything
> patch link:    https://lore.kernel.org/r/20240703212918.2417843-8-peterx%40redhat.com
> patch subject: [PATCH v2 7/8] mm/x86: Add missing pud helpers
> config: i386-randconfig-011-20240706 (https://download.01.org/0day-ci/archive/20240706/202407061716.WH5NMiL2-lkp@intel.com/config)
> compiler: gcc-11 (Ubuntu 11.4.0-4ubuntu1) 11.4.0
> reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240706/202407061716.WH5NMiL2-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/202407061716.WH5NMiL2-lkp@intel.com/
> 
> All errors (new ones prefixed by >>):
> 
>    In file included from arch/x86/include/asm/atomic.h:8,
>                     from include/linux/atomic.h:7,
>                     from include/linux/jump_label.h:256,
>                     from include/linux/static_key.h:1,
>                     from arch/x86/include/asm/nospec-branch.h:6,
>                     from arch/x86/include/asm/irqflags.h:9,
>                     from include/linux/irqflags.h:18,
>                     from include/linux/spinlock.h:59,
>                     from include/linux/mmzone.h:8,
>                     from include/linux/gfp.h:7,
>                     from include/linux/mm.h:7,
>                     from arch/x86/mm/pgtable.c:2:
>    In function 'pudp_establish',
>        inlined from 'pudp_invalidate' at arch/x86/mm/pgtable.c:649:14:
> >> arch/x86/include/asm/cmpxchg.h:67:25: error: call to '__xchg_wrong_size' declared with attribute error: Bad argument size for xchg
>       67 |                         __ ## op ## _wrong_size();                      \
>          |                         ^~~~~~~~~~~~~~~~~~~~~~~~~
>    arch/x86/include/asm/cmpxchg.h:78:33: note: in expansion of macro '__xchg_op'
>       78 | #define arch_xchg(ptr, v)       __xchg_op((ptr), (v), xchg, "")
>          |                                 ^~~~~~~~~
>    include/linux/atomic/atomic-arch-fallback.h:12:18: note: in expansion of macro 'arch_xchg'
>       12 | #define raw_xchg arch_xchg
>          |                  ^~~~~~~~~
>    include/linux/atomic/atomic-instrumented.h:4758:9: note: in expansion of macro 'raw_xchg'
>     4758 |         raw_xchg(__ai_ptr, __VA_ARGS__); \
>          |         ^~~~~~~~
>    arch/x86/include/asm/pgtable.h:1415:24: note: in expansion of macro 'xchg'
>     1415 |                 return xchg(pudp, pud);
>          |                        ^~~~

So this is the PAE paging on i386 which indeed didn't get covered in my
testsuite.. where it only covered allno/alldef which were always 2lvls.

I'll fix it when I repost, I'll add PAE into my harness too.
diff mbox series

Patch

diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h
index cdf044c2ad6e..701593c53f3b 100644
--- a/arch/x86/include/asm/pgtable.h
+++ b/arch/x86/include/asm/pgtable.h
@@ -782,6 +782,12 @@  static inline pmd_t pmd_mkinvalid(pmd_t pmd)
 		      __pgprot(pmd_flags(pmd) & ~(_PAGE_PRESENT|_PAGE_PROTNONE)));
 }
 
+static inline pud_t pud_mkinvalid(pud_t pud)
+{
+	return pfn_pud(pud_pfn(pud),
+		       __pgprot(pud_flags(pud) & ~(_PAGE_PRESENT|_PAGE_PROTNONE)));
+}
+
 static inline u64 flip_protnone_guard(u64 oldval, u64 val, u64 mask);
 
 static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
@@ -829,14 +835,8 @@  static inline pmd_t pmd_modify(pmd_t pmd, pgprot_t newprot)
 	pmd_result = __pmd(val);
 
 	/*
-	 * To avoid creating Write=0,Dirty=1 PMDs, pte_modify() needs to avoid:
-	 *  1. Marking Write=0 PMDs Dirty=1
-	 *  2. Marking Dirty=1 PMDs Write=0
-	 *
-	 * The first case cannot happen because the _PAGE_CHG_MASK will filter
-	 * out any Dirty bit passed in newprot. Handle the second case by
-	 * going through the mksaveddirty exercise. Only do this if the old
-	 * value was Write=1 to avoid doing this on Shadow Stack PTEs.
+	 * Avoid creating shadow stack PMD by accident.  See comment in
+	 * pte_modify().
 	 */
 	if (oldval & _PAGE_RW)
 		pmd_result = pmd_mksaveddirty(pmd_result);
@@ -846,6 +846,29 @@  static inline pmd_t pmd_modify(pmd_t pmd, pgprot_t newprot)
 	return pmd_result;
 }
 
+static inline pud_t pud_modify(pud_t pud, pgprot_t newprot)
+{
+	pudval_t val = pud_val(pud), oldval = val;
+	pud_t pud_result;
+
+	val &= _HPAGE_CHG_MASK;
+	val |= check_pgprot(newprot) & ~_HPAGE_CHG_MASK;
+	val = flip_protnone_guard(oldval, val, PHYSICAL_PUD_PAGE_MASK);
+
+	pud_result = __pud(val);
+
+	/*
+	 * Avoid creating shadow stack PUD by accident.  See comment in
+	 * pte_modify().
+	 */
+	if (oldval & _PAGE_RW)
+		pud_result = pud_mksaveddirty(pud_result);
+	else
+		pud_result = pud_clear_saveddirty(pud_result);
+
+	return pud_result;
+}
+
 /*
  * mprotect needs to preserve PAT and encryption bits when updating
  * vm_page_prot
@@ -1384,10 +1407,26 @@  static inline pmd_t pmdp_establish(struct vm_area_struct *vma,
 }
 #endif
 
+static inline pud_t pudp_establish(struct vm_area_struct *vma,
+		unsigned long address, pud_t *pudp, pud_t pud)
+{
+	page_table_check_pud_set(vma->vm_mm, pudp, pud);
+	if (IS_ENABLED(CONFIG_SMP)) {
+		return xchg(pudp, pud);
+	} else {
+		pud_t old = *pudp;
+		WRITE_ONCE(*pudp, pud);
+		return old;
+	}
+}
+
 #define __HAVE_ARCH_PMDP_INVALIDATE_AD
 extern pmd_t pmdp_invalidate_ad(struct vm_area_struct *vma,
 				unsigned long address, pmd_t *pmdp);
 
+pud_t pudp_invalidate(struct vm_area_struct *vma, unsigned long address,
+		      pud_t *pudp);
+
 /*
  * Page table pages are page-aligned.  The lower half of the top
  * level is used for userspace and the top half for the kernel.
diff --git a/arch/x86/mm/pgtable.c b/arch/x86/mm/pgtable.c
index 564b8945951e..9d97a1b99160 100644
--- a/arch/x86/mm/pgtable.c
+++ b/arch/x86/mm/pgtable.c
@@ -641,6 +641,17 @@  pmd_t pmdp_invalidate_ad(struct vm_area_struct *vma, unsigned long address,
 }
 #endif
 
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+pud_t pudp_invalidate(struct vm_area_struct *vma, unsigned long address,
+		     pud_t *pudp)
+{
+	VM_WARN_ON_ONCE(!pud_present(*pudp));
+	pud_t old = pudp_establish(vma, address, pudp, pud_mkinvalid(*pudp));
+	flush_pud_tlb_range(vma, address, address + HPAGE_PUD_SIZE);
+	return old;
+}
+#endif
+
 /**
  * reserve_top_address - reserves a hole in the top of kernel address space
  * @reserve - size of hole to reserve