lkml.org 
[lkml]   [2022]   [Dec]   [17]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
Subject[tip: x86/mm] x86/mm/pae: Make pmd_t similar to pte_t
The following commit has been merged into the x86/mm branch of tip:

Commit-ID: fbfdec9989e69e0b17aa3bf32fcb22d04cc33301
Gitweb: https://git.kernel.org/tip/fbfdec9989e69e0b17aa3bf32fcb22d04cc33301
Author: Peter Zijlstra <peterz@infradead.org>
AuthorDate: Thu, 26 Nov 2020 17:02:29 +01:00
Committer: Dave Hansen <dave.hansen@linux.intel.com>
CommitterDate: Thu, 15 Dec 2022 10:37:27 -08:00

x86/mm/pae: Make pmd_t similar to pte_t

Instead of mucking about with at least 2 different ways of fudging
it, do the same thing we do for pte_t.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20221022114424.580310787%40infradead.org
---
arch/x86/include/asm/pgtable-3level.h | 42 ++++++--------------
arch/x86/include/asm/pgtable-3level_types.h | 7 +++-
arch/x86/include/asm/pgtable_64_types.h | 1 +-
arch/x86/include/asm/pgtable_types.h | 4 +--
4 files changed, 23 insertions(+), 31 deletions(-)

diff --git a/arch/x86/include/asm/pgtable-3level.h b/arch/x86/include/asm/pgtable-3level.h
index 28421a8..28556d2 100644
--- a/arch/x86/include/asm/pgtable-3level.h
+++ b/arch/x86/include/asm/pgtable-3level.h
@@ -87,7 +87,7 @@ static inline pmd_t pmd_read_atomic(pmd_t *pmdp)
ret |= ((pmdval_t)*(tmp + 1)) << 32;
}

- return (pmd_t) { ret };
+ return (pmd_t) { .pmd = ret };
}

static inline void native_set_pte_atomic(pte_t *ptep, pte_t pte)
@@ -121,12 +121,11 @@ static inline void native_pte_clear(struct mm_struct *mm, unsigned long addr,
ptep->pte_high = 0;
}

-static inline void native_pmd_clear(pmd_t *pmd)
+static inline void native_pmd_clear(pmd_t *pmdp)
{
- u32 *tmp = (u32 *)pmd;
- *tmp = 0;
+ pmdp->pmd_low = 0;
smp_wmb();
- *(tmp + 1) = 0;
+ pmdp->pmd_high = 0;
}

static inline void native_pud_clear(pud_t *pudp)
@@ -162,25 +161,17 @@ static inline pte_t native_ptep_get_and_clear(pte_t *ptep)
#define native_ptep_get_and_clear(xp) native_local_ptep_get_and_clear(xp)
#endif

-union split_pmd {
- struct {
- u32 pmd_low;
- u32 pmd_high;
- };
- pmd_t pmd;
-};
-
#ifdef CONFIG_SMP
static inline pmd_t native_pmdp_get_and_clear(pmd_t *pmdp)
{
- union split_pmd res, *orig = (union split_pmd *)pmdp;
+ pmd_t res;

/* xchg acts as a barrier before setting of the high bits */
- res.pmd_low = xchg(&orig->pmd_low, 0);
- res.pmd_high = orig->pmd_high;
- orig->pmd_high = 0;
+ res.pmd_low = xchg(&pmdp->pmd_low, 0);
+ res.pmd_high = READ_ONCE(pmdp->pmd_high);
+ WRITE_ONCE(pmdp->pmd_high, 0);

- return res.pmd;
+ return res;
}
#else
#define native_pmdp_get_and_clear(xp) native_local_pmdp_get_and_clear(xp)
@@ -199,17 +190,12 @@ static inline pmd_t pmdp_establish(struct vm_area_struct *vma,
* anybody.
*/
if (!(pmd_val(pmd) & _PAGE_PRESENT)) {
- union split_pmd old, new, *ptr;
-
- ptr = (union split_pmd *)pmdp;
-
- new.pmd = pmd;
-
/* xchg acts as a barrier before setting of the high bits */
- old.pmd_low = xchg(&ptr->pmd_low, new.pmd_low);
- old.pmd_high = ptr->pmd_high;
- ptr->pmd_high = new.pmd_high;
- return old.pmd;
+ old.pmd_low = xchg(&pmdp->pmd_low, pmd.pmd_low);
+ old.pmd_high = READ_ONCE(pmdp->pmd_high);
+ WRITE_ONCE(pmdp->pmd_high, pmd.pmd_high);
+
+ return old;
}

do {
diff --git a/arch/x86/include/asm/pgtable-3level_types.h b/arch/x86/include/asm/pgtable-3level_types.h
index 56baf43..8091134 100644
--- a/arch/x86/include/asm/pgtable-3level_types.h
+++ b/arch/x86/include/asm/pgtable-3level_types.h
@@ -18,6 +18,13 @@ typedef union {
};
pteval_t pte;
} pte_t;
+
+typedef union {
+ struct {
+ unsigned long pmd_low, pmd_high;
+ };
+ pmdval_t pmd;
+} pmd_t;
#endif /* !__ASSEMBLY__ */

#define SHARED_KERNEL_PMD (!static_cpu_has(X86_FEATURE_PTI))
diff --git a/arch/x86/include/asm/pgtable_64_types.h b/arch/x86/include/asm/pgtable_64_types.h
index 04f3606..38bf837 100644
--- a/arch/x86/include/asm/pgtable_64_types.h
+++ b/arch/x86/include/asm/pgtable_64_types.h
@@ -19,6 +19,7 @@ typedef unsigned long pgdval_t;
typedef unsigned long pgprotval_t;

typedef struct { pteval_t pte; } pte_t;
+typedef struct { pmdval_t pmd; } pmd_t;

#ifdef CONFIG_X86_5LEVEL
extern unsigned int __pgtable_l5_enabled;
diff --git a/arch/x86/include/asm/pgtable_types.h b/arch/x86/include/asm/pgtable_types.h
index aa174fe..447d4be 100644
--- a/arch/x86/include/asm/pgtable_types.h
+++ b/arch/x86/include/asm/pgtable_types.h
@@ -361,11 +361,9 @@ static inline pudval_t native_pud_val(pud_t pud)
#endif

#if CONFIG_PGTABLE_LEVELS > 2
-typedef struct { pmdval_t pmd; } pmd_t;
-
static inline pmd_t native_make_pmd(pmdval_t val)
{
- return (pmd_t) { val };
+ return (pmd_t) { .pmd = val };
}

static inline pmdval_t native_pmd_val(pmd_t pmd)
\
 
 \ /
  Last update: 2022-12-17 19:58    [W:0.033 / U:0.344 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site