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Message-ID: <20240702151431.1160915-1-chenhuacai@loongson.cn>
Date: Tue, 2 Jul 2024 23:14:31 +0800
From: Huacai Chen <chenhuacai@...ngson.cn>
To: Huacai Chen <chenhuacai@...nel.org>
Cc: loongarch@...ts.linux.dev,
Xuefeng Li <lixuefeng@...ngson.cn>,
Guo Ren <guoren@...nel.org>,
Xuerui Wang <kernel@...0n.name>,
Jiaxun Yang <jiaxun.yang@...goat.com>,
linux-kernel@...r.kernel.org,
loongson-kernel@...ts.loongnix.cn,
Huacai Chen <chenhuacai@...ngson.cn>
Subject: [PATCH] LoongArch: Add ARCH_HAS_PTE_DEVMAP support
In order for things like get_user_pages() to work on ZONE_DEVICE memory,
we need a software PTE bit to identify device-backed PFNs. Hook this up
along with the relevant helpers to join in with ARCH_HAS_PTE_DEVMAP.
Signed-off-by: Huacai Chen <chenhuacai@...ngson.cn>
---
arch/loongarch/Kconfig | 1 +
arch/loongarch/include/asm/pgtable-bits.h | 6 ++++--
arch/loongarch/include/asm/pgtable.h | 19 +++++++++++++++++++
3 files changed, 24 insertions(+), 2 deletions(-)
diff --git a/arch/loongarch/Kconfig b/arch/loongarch/Kconfig
index ddc042895d01..d8ca8b1b01f3 100644
--- a/arch/loongarch/Kconfig
+++ b/arch/loongarch/Kconfig
@@ -22,6 +22,7 @@ config LOONGARCH
select ARCH_HAS_KERNEL_FPU_SUPPORT if CPU_HAS_FPU
select ARCH_HAS_NMI_SAFE_THIS_CPU_OPS
select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
+ select ARCH_HAS_PTE_DEVMAP
select ARCH_HAS_PTE_SPECIAL
select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST
select ARCH_INLINE_READ_LOCK if !PREEMPTION
diff --git a/arch/loongarch/include/asm/pgtable-bits.h b/arch/loongarch/include/asm/pgtable-bits.h
index 21319c1e045c..82cd3a9f094b 100644
--- a/arch/loongarch/include/asm/pgtable-bits.h
+++ b/arch/loongarch/include/asm/pgtable-bits.h
@@ -22,6 +22,7 @@
#define _PAGE_PFN_SHIFT 12
#define _PAGE_SWP_EXCLUSIVE_SHIFT 23
#define _PAGE_PFN_END_SHIFT 48
+#define _PAGE_DEVMAP_SHIFT 59
#define _PAGE_PRESENT_INVALID_SHIFT 60
#define _PAGE_NO_READ_SHIFT 61
#define _PAGE_NO_EXEC_SHIFT 62
@@ -35,6 +36,7 @@
#define _PAGE_MODIFIED (_ULCAST_(1) << _PAGE_MODIFIED_SHIFT)
#define _PAGE_PROTNONE (_ULCAST_(1) << _PAGE_PROTNONE_SHIFT)
#define _PAGE_SPECIAL (_ULCAST_(1) << _PAGE_SPECIAL_SHIFT)
+#define _PAGE_DEVMAP (_ULCAST_(1) << _PAGE_DEVMAP_SHIFT)
/* We borrow bit 23 to store the exclusive marker in swap PTEs. */
#define _PAGE_SWP_EXCLUSIVE (_ULCAST_(1) << _PAGE_SWP_EXCLUSIVE_SHIFT)
@@ -74,8 +76,8 @@
#define __READABLE (_PAGE_VALID)
#define __WRITEABLE (_PAGE_DIRTY | _PAGE_WRITE)
-#define _PAGE_CHG_MASK (_PAGE_MODIFIED | _PAGE_SPECIAL | _PFN_MASK | _CACHE_MASK | _PAGE_PLV)
-#define _HPAGE_CHG_MASK (_PAGE_MODIFIED | _PAGE_SPECIAL | _PFN_MASK | _CACHE_MASK | _PAGE_PLV | _PAGE_HUGE)
+#define _PAGE_CHG_MASK (_PAGE_MODIFIED | _PAGE_SPECIAL | _PAGE_DEVMAP | _PFN_MASK | _CACHE_MASK | _PAGE_PLV)
+#define _HPAGE_CHG_MASK (_PAGE_MODIFIED | _PAGE_SPECIAL | _PAGE_DEVMAP | _PFN_MASK | _CACHE_MASK | _PAGE_PLV | _PAGE_HUGE)
#define PAGE_NONE __pgprot(_PAGE_PROTNONE | _PAGE_NO_READ | \
_PAGE_USER | _CACHE_CC)
diff --git a/arch/loongarch/include/asm/pgtable.h b/arch/loongarch/include/asm/pgtable.h
index af3acdf3481a..0e821be63268 100644
--- a/arch/loongarch/include/asm/pgtable.h
+++ b/arch/loongarch/include/asm/pgtable.h
@@ -424,6 +424,9 @@ static inline int pte_special(pte_t pte) { return pte_val(pte) & _PAGE_SPECIAL;
static inline pte_t pte_mkspecial(pte_t pte) { pte_val(pte) |= _PAGE_SPECIAL; return pte; }
#endif /* CONFIG_ARCH_HAS_PTE_SPECIAL */
+static inline int pte_devmap(pte_t pte) { return !!(pte_val(pte) & _PAGE_DEVMAP); }
+static inline pte_t pte_mkdevmap(pte_t pte) { pte_val(pte) |= _PAGE_DEVMAP; return pte; }
+
#define pte_accessible pte_accessible
static inline unsigned long pte_accessible(struct mm_struct *mm, pte_t a)
{
@@ -558,6 +561,17 @@ static inline pmd_t pmd_mkyoung(pmd_t pmd)
return pmd;
}
+static inline int pmd_devmap(pmd_t pmd)
+{
+ return !!(pmd_val(pmd) & _PAGE_DEVMAP);
+}
+
+static inline pmd_t pmd_mkdevmap(pmd_t pmd)
+{
+ pmd_val(pmd) |= _PAGE_DEVMAP;
+ return pmd;
+}
+
static inline struct page *pmd_page(pmd_t pmd)
{
if (pmd_trans_huge(pmd))
@@ -613,6 +627,11 @@ static inline long pmd_protnone(pmd_t pmd)
#define pmd_leaf(pmd) ((pmd_val(pmd) & _PAGE_HUGE) != 0)
#define pud_leaf(pud) ((pud_val(pud) & _PAGE_HUGE) != 0)
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+#define pud_devmap(pud) (0)
+#define pgd_devmap(pgd) (0)
+#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
+
/*
* We provide our own get_unmapped area to cope with the virtual aliasing
* constraints placed on us by the cache architecture.
--
2.43.0
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