From: Peter Zijlstra <peterz@infradead.org>
To: x86@kernel.org, willy@infradead.org
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
aarcange@redhat.com, kirill.shutemov@linux.intel.com,
jroedel@suse.de, peterz@infradead.org
Subject: [RFC][PATCH 2/9] x86/mm/pae: Make pmd_t similar to pte_t
Date: Mon, 30 Nov 2020 12:27:07 +0100 [thread overview]
Message-ID: <20201130113602.900215647@infradead.org> (raw)
In-Reply-To: 20201130112705.900705277@infradead.org
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>
---
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(-)
--- 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_
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(stru
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_
#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(struc
* 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 {
--- 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))
--- 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;
--- a/arch/x86/include/asm/pgtable_types.h
+++ b/arch/x86/include/asm/pgtable_types.h
@@ -381,11 +381,9 @@ static inline pudval_t native_pud_val(pu
#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)
next prev parent reply other threads:[~2020-11-30 11:39 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-30 11:27 [RFC][PATCH 0/9] Clean up i386-PAE Peter Zijlstra
2020-11-30 11:27 ` [RFC][PATCH 1/9] mm: Update ptep_get_lockless()s comment Peter Zijlstra
2020-11-30 11:27 ` Peter Zijlstra [this message]
2020-11-30 11:27 ` [RFC][PATCH 3/9] sh/mm: Make pmd_t similar to pte_t Peter Zijlstra
2020-11-30 14:10 ` David Laight
2020-11-30 14:21 ` Peter Zijlstra
2020-11-30 11:27 ` [RFC][PATCH 4/9] mm: Fix pmd_read_atomic() Peter Zijlstra
2020-11-30 11:27 ` [RFC][PATCH 5/9] mm: Rename pmd_read_atomic() Peter Zijlstra
2020-11-30 15:31 ` Jason Gunthorpe
2020-12-01 8:57 ` Peter Zijlstra
2020-11-30 11:27 ` [RFC][PATCH 6/9] mm/gup: Fix the lockless walkers Peter Zijlstra
2020-11-30 11:27 ` [RFC][PATCH 7/9] x86/mm/pae: Dont (ab)use atomic64 Peter Zijlstra
2020-11-30 11:27 ` [RFC][PATCH 8/9] x86/mm/pae: Use WRITE_ONCE() Peter Zijlstra
2020-11-30 11:27 ` [RFC][PATCH 9/9] x86/mm/pae: Be consistent with pXXp_get_and_clear() Peter Zijlstra
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20201130113602.900215647@infradead.org \
--to=peterz@infradead.org \
--cc=aarcange@redhat.com \
--cc=jroedel@suse.de \
--cc=kirill.shutemov@linux.intel.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=willy@infradead.org \
--cc=x86@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.