From: Will Deacon <will.deacon@arm.com>
To: linux-kernel@vger.kernel.org, linux-mm@kvack.org
Cc: cpandya@codeaurora.org, toshi.kani@hpe.com, tglx@linutronix.de,
mhocko@suse.com, akpm@linux-foundation.org,
sean.j.christopherson@intel.com,
Will Deacon <will.deacon@arm.com>
Subject: [PATCH v4 5/5] lib/ioremap: Ensure break-before-make is used for huge p4d mappings
Date: Mon, 26 Nov 2018 17:07:47 +0000 [thread overview]
Message-ID: <1543252067-30831-6-git-send-email-will.deacon@arm.com> (raw)
In-Reply-To: <1543252067-30831-1-git-send-email-will.deacon@arm.com>
Whilst no architectures actually enable support for huge p4d mappings
in the vmap area, the code that is implemented should be using
break-before-make, as we do for pud and pmd huge entries.
Cc: Chintan Pandya <cpandya@codeaurora.org>
Cc: Toshi Kani <toshi.kani@hpe.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Toshi Kani <toshi.kani@hpe.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
---
arch/arm64/mm/mmu.c | 5 +++++
arch/x86/mm/pgtable.c | 8 ++++++++
include/asm-generic/pgtable.h | 5 +++++
lib/ioremap.c | 27 +++++++++++++++++++++------
4 files changed, 39 insertions(+), 6 deletions(-)
diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
index 786cfa6355be..cf9a26d3d7f5 100644
--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c
@@ -1028,3 +1028,8 @@ int pud_free_pmd_page(pud_t *pudp, unsigned long addr)
pmd_free(NULL, table);
return 1;
}
+
+int p4d_free_pud_page(p4d_t *p4d, unsigned long addr)
+{
+ return 0; /* Don't attempt a block mapping */
+}
diff --git a/arch/x86/mm/pgtable.c b/arch/x86/mm/pgtable.c
index e95a7d6ac8f8..b0284eab14dc 100644
--- a/arch/x86/mm/pgtable.c
+++ b/arch/x86/mm/pgtable.c
@@ -794,6 +794,14 @@ int pmd_clear_huge(pmd_t *pmd)
return 0;
}
+/*
+ * Until we support 512GB pages, skip them in the vmap area.
+ */
+int p4d_free_pud_page(p4d_t *p4d, unsigned long addr)
+{
+ return 0;
+}
+
#ifdef CONFIG_X86_64
/**
* pud_free_pmd_page - Clear pud entry and free pmd page.
diff --git a/include/asm-generic/pgtable.h b/include/asm-generic/pgtable.h
index 359fb935ded6..e0381a4ce7d4 100644
--- a/include/asm-generic/pgtable.h
+++ b/include/asm-generic/pgtable.h
@@ -1019,6 +1019,7 @@ int pud_set_huge(pud_t *pud, phys_addr_t addr, pgprot_t prot);
int pmd_set_huge(pmd_t *pmd, phys_addr_t addr, pgprot_t prot);
int pud_clear_huge(pud_t *pud);
int pmd_clear_huge(pmd_t *pmd);
+int p4d_free_pud_page(p4d_t *p4d, unsigned long addr);
int pud_free_pmd_page(pud_t *pud, unsigned long addr);
int pmd_free_pte_page(pmd_t *pmd, unsigned long addr);
#else /* !CONFIG_HAVE_ARCH_HUGE_VMAP */
@@ -1046,6 +1047,10 @@ static inline int pmd_clear_huge(pmd_t *pmd)
{
return 0;
}
+static inline int p4d_free_pud_page(p4d_t *p4d, unsigned long addr)
+{
+ return 0;
+}
static inline int pud_free_pmd_page(pud_t *pud, unsigned long addr)
{
return 0;
diff --git a/lib/ioremap.c b/lib/ioremap.c
index 10d7c5485c39..063213685563 100644
--- a/lib/ioremap.c
+++ b/lib/ioremap.c
@@ -156,6 +156,25 @@ static inline int ioremap_pud_range(p4d_t *p4d, unsigned long addr,
return 0;
}
+static int ioremap_try_huge_p4d(p4d_t *p4d, unsigned long addr,
+ unsigned long end, phys_addr_t phys_addr,
+ pgprot_t prot)
+{
+ if (!ioremap_p4d_enabled())
+ return 0;
+
+ if ((end - addr) != P4D_SIZE)
+ return 0;
+
+ if (!IS_ALIGNED(phys_addr, P4D_SIZE))
+ return 0;
+
+ if (p4d_present(*p4d) && !p4d_free_pud_page(p4d, addr))
+ return 0;
+
+ return p4d_set_huge(p4d, phys_addr, prot);
+}
+
static inline int ioremap_p4d_range(pgd_t *pgd, unsigned long addr,
unsigned long end, phys_addr_t phys_addr, pgprot_t prot)
{
@@ -168,12 +187,8 @@ static inline int ioremap_p4d_range(pgd_t *pgd, unsigned long addr,
do {
next = p4d_addr_end(addr, end);
- if (ioremap_p4d_enabled() &&
- ((next - addr) == P4D_SIZE) &&
- IS_ALIGNED(phys_addr, P4D_SIZE)) {
- if (p4d_set_huge(p4d, phys_addr, prot))
- continue;
- }
+ if (ioremap_try_huge_p4d(p4d, addr, next, phys_addr, prot))
+ continue;
if (ioremap_pud_range(p4d, addr, next, phys_addr, prot))
return -ENOMEM;
--
2.1.4
prev parent reply other threads:[~2018-11-26 17:07 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-26 17:07 [PATCH v4 0/5] Clean up huge vmap and ioremap code Will Deacon
2018-11-26 17:07 ` [PATCH v4 1/5] ioremap: Rework pXd_free_pYd_page() API Will Deacon
2018-11-26 17:07 ` [PATCH v4 2/5] arm64: mmu: Drop pXd_present() checks from pXd_free_pYd_table() Will Deacon
2018-11-26 17:07 ` [PATCH v4 3/5] x86/pgtable: Drop pXd_none() " Will Deacon
2018-11-26 17:07 ` [PATCH v4 4/5] lib/ioremap: Ensure phys_addr actually corresponds to a physical address Will Deacon
2018-11-26 19:00 ` Sean Christopherson
2018-11-27 12:12 ` Will Deacon
2018-11-26 17:07 ` Will Deacon [this message]
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