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Message-Id: <20200206030900.147032-7-leonardo@linux.ibm.com>
Date: Thu, 6 Feb 2020 00:08:55 -0300
From: Leonardo Bras <leonardo@...ux.ibm.com>
To: Benjamin Herrenschmidt <benh@...nel.crashing.org>,
Paul Mackerras <paulus@...ba.org>,
Michael Ellerman <mpe@...erman.id.au>,
Arnd Bergmann <arnd@...db.de>,
Andrew Morton <akpm@...ux-foundation.org>,
"Aneesh Kumar K.V" <aneesh.kumar@...ux.ibm.com>,
Nicholas Piggin <npiggin@...il.com>,
Christophe Leroy <christophe.leroy@....fr>,
Steven Price <steven.price@....com>,
Robin Murphy <robin.murphy@....com>,
Leonardo Bras <leonardo@...ux.ibm.com>,
Mahesh Salgaonkar <mahesh@...ux.vnet.ibm.com>,
Balbir Singh <bsingharora@...il.com>,
Reza Arbab <arbab@...ux.ibm.com>,
Thomas Gleixner <tglx@...utronix.de>,
Allison Randal <allison@...utok.net>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
Mike Rapoport <rppt@...ux.ibm.com>,
Michal Suchanek <msuchanek@...e.de>
Cc: linuxppc-dev@...ts.ozlabs.org, linux-kernel@...r.kernel.org,
kvm-ppc@...r.kernel.org, linux-arch@...r.kernel.org,
linux-mm@...ck.org
Subject: [PATCH v6 06/11] powerpc/mm/book3s64/hash: Use functions to track lockless pgtbl walks
Applies the new tracking functions to all hash-related functions that do
lockless pagetable walks.
hash_page_mm: Adds comment that explain that there is no need to
local_int_disable/save given that it is only called from DataAccess
interrupt, so interrupts are already disabled.
local_irq_{save,restore} is already inside {begin,end}_lockless_pgtbl_walk,
so there is no need to repeat it here.
Variable that saves the irq mask was renamed from flags to irq_mask so it
doesn't lose meaning now it's not directly passed to local_irq_* functions.
Signed-off-by: Leonardo Bras <leonardo@...ux.ibm.com>
---
arch/powerpc/mm/book3s64/hash_tlb.c | 6 +++---
arch/powerpc/mm/book3s64/hash_utils.c | 27 +++++++++++++++++----------
2 files changed, 20 insertions(+), 13 deletions(-)
diff --git a/arch/powerpc/mm/book3s64/hash_tlb.c b/arch/powerpc/mm/book3s64/hash_tlb.c
index 4a70d8dd39cd..86547c4151f6 100644
--- a/arch/powerpc/mm/book3s64/hash_tlb.c
+++ b/arch/powerpc/mm/book3s64/hash_tlb.c
@@ -194,7 +194,7 @@ void __flush_hash_table_range(struct mm_struct *mm, unsigned long start,
{
bool is_thp;
int hugepage_shift;
- unsigned long flags;
+ unsigned long irq_mask;
start = _ALIGN_DOWN(start, PAGE_SIZE);
end = _ALIGN_UP(end, PAGE_SIZE);
@@ -209,7 +209,7 @@ void __flush_hash_table_range(struct mm_struct *mm, unsigned long start,
* to being hashed). This is not the most performance oriented
* way to do things but is fine for our needs here.
*/
- local_irq_save(flags);
+ irq_mask = begin_lockless_pgtbl_walk();
arch_enter_lazy_mmu_mode();
for (; start < end; start += PAGE_SIZE) {
pte_t *ptep = find_current_mm_pte(mm->pgd, start, &is_thp,
@@ -229,7 +229,7 @@ void __flush_hash_table_range(struct mm_struct *mm, unsigned long start,
hpte_need_flush(mm, start, ptep, pte, hugepage_shift);
}
arch_leave_lazy_mmu_mode();
- local_irq_restore(flags);
+ end_lockless_pgtbl_walk(irq_mask);
}
void flush_tlb_pmd_range(struct mm_struct *mm, pmd_t *pmd, unsigned long addr)
diff --git a/arch/powerpc/mm/book3s64/hash_utils.c b/arch/powerpc/mm/book3s64/hash_utils.c
index 523d4d39d11e..e6d4ab42173b 100644
--- a/arch/powerpc/mm/book3s64/hash_utils.c
+++ b/arch/powerpc/mm/book3s64/hash_utils.c
@@ -1341,12 +1341,16 @@ int hash_page_mm(struct mm_struct *mm, unsigned long ea,
ea &= ~((1ul << mmu_psize_defs[psize].shift) - 1);
#endif /* CONFIG_PPC_64K_PAGES */
- /* Get PTE and page size from page tables */
+ /* Get PTE and page size from page tables :
+ * Called in from DataAccess interrupt (data_access_common: 0x300),
+ * interrupts are disabled here.
+ */
+ __begin_lockless_pgtbl_walk(false);
ptep = find_linux_pte(pgdir, ea, &is_thp, &hugeshift);
if (ptep == NULL || !pte_present(*ptep)) {
DBG_LOW(" no PTE !\n");
rc = 1;
- goto bail;
+ goto bail_pgtbl_walk;
}
/* Add _PAGE_PRESENT to the required access perm */
@@ -1359,7 +1363,7 @@ int hash_page_mm(struct mm_struct *mm, unsigned long ea,
if (!check_pte_access(access, pte_val(*ptep))) {
DBG_LOW(" no access !\n");
rc = 1;
- goto bail;
+ goto bail_pgtbl_walk;
}
if (hugeshift) {
@@ -1383,7 +1387,7 @@ int hash_page_mm(struct mm_struct *mm, unsigned long ea,
if (current->mm == mm)
check_paca_psize(ea, mm, psize, user_region);
- goto bail;
+ goto bail_pgtbl_walk;
}
#ifndef CONFIG_PPC_64K_PAGES
@@ -1457,6 +1461,8 @@ int hash_page_mm(struct mm_struct *mm, unsigned long ea,
#endif
DBG_LOW(" -> rc=%d\n", rc);
+bail_pgtbl_walk:
+ __end_lockless_pgtbl_walk(0, false);
bail:
exception_exit(prev_state);
return rc;
@@ -1545,7 +1551,7 @@ static void hash_preload(struct mm_struct *mm, unsigned long ea,
unsigned long vsid;
pgd_t *pgdir;
pte_t *ptep;
- unsigned long flags;
+ unsigned long irq_mask;
int rc, ssize, update_flags = 0;
unsigned long access = _PAGE_PRESENT | _PAGE_READ | (is_exec ? _PAGE_EXEC : 0);
@@ -1567,11 +1573,12 @@ static void hash_preload(struct mm_struct *mm, unsigned long ea,
vsid = get_user_vsid(&mm->context, ea, ssize);
if (!vsid)
return;
+
/*
* Hash doesn't like irqs. Walking linux page table with irq disabled
* saves us from holding multiple locks.
*/
- local_irq_save(flags);
+ irq_mask = begin_lockless_pgtbl_walk();
/*
* THP pages use update_mmu_cache_pmd. We don't do
@@ -1616,7 +1623,7 @@ static void hash_preload(struct mm_struct *mm, unsigned long ea,
mm_ctx_user_psize(&mm->context),
pte_val(*ptep));
out_exit:
- local_irq_restore(flags);
+ end_lockless_pgtbl_walk(irq_mask);
}
/*
@@ -1679,16 +1686,16 @@ u16 get_mm_addr_key(struct mm_struct *mm, unsigned long address)
{
pte_t *ptep;
u16 pkey = 0;
- unsigned long flags;
+ unsigned long irq_mask;
if (!mm || !mm->pgd)
return 0;
- local_irq_save(flags);
+ irq_mask = begin_lockless_pgtbl_walk();
ptep = find_linux_pte(mm->pgd, address, NULL, NULL);
if (ptep)
pkey = pte_to_pkey_bits(pte_val(READ_ONCE(*ptep)));
- local_irq_restore(flags);
+ end_lockless_pgtbl_walk(irq_mask);
return pkey;
}
--
2.24.1
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