[PATCH] MIPS: make userspace mapping young by default

Huang Pei
2020-08-25T03:23:03Z

This patch adds support for non-rixi, based on [1].

MIPS page fault path take 3 exception (1 tlb miss + 2 tlb invalid), but
the second tlb invalid exception is just caused by __update_tlb from
do_page_fault writing tlb without _PAGE_VALID set. With this patch, it
only take 1 tlb miss + 1 tlb invalid exceptions

[1]: https://lkml.kernel.org/lkml/1591416169-26666-1-git-send-email-maobibo@loongson.cn/

Signed-off-by: Huang Pei <huangpei@loongson.cn>
---
arch/mips/include/asm/pgtable.h | 32 +++++++++++++++-----------------
arch/mips/mm/cache.c | 25 +++++++++++++------------
mm/memory.c | 3 ---
3 files changed, 28 insertions(+), 32 deletions(-)

diff --git a/arch/mips/include/asm/pgtable.h b/arch/mips/include/asm/pgtable.h
index dd7a0f552cac..aaafe3d6a0a1 100644
--- a/arch/mips/include/asm/pgtable.h
+++ b/arch/mips/include/asm/pgtable.h
@@ -25,22 +25,22 @@
struct mm_struct;
struct vm_area_struct;

-#define PAGE_NONE __pgprot(_PAGE_PRESENT | _PAGE_NO_READ | \
- _page_cachable_default)
-#define PAGE_SHARED __pgprot(_PAGE_PRESENT | _PAGE_WRITE | \
- _page_cachable_default)
-#define PAGE_COPY __pgprot(_PAGE_PRESENT | _PAGE_NO_EXEC | \
- _page_cachable_default)
-#define PAGE_READONLY __pgprot(_PAGE_PRESENT | \
- _page_cachable_default)
-#define PAGE_KERNEL __pgprot(_PAGE_PRESENT | __READABLE | __WRITEABLE | \
- _PAGE_GLOBAL | _page_cachable_default)
-#define PAGE_KERNEL_NC __pgprot(_PAGE_PRESENT | __READABLE | __WRITEABLE | \
- _PAGE_GLOBAL | _CACHE_CACHABLE_NONCOHERENT)
-#define PAGE_USERIO __pgprot(_PAGE_PRESENT | _PAGE_WRITE | \
- _page_cachable_default)
+#define PAGE_NONE __pgprot(_PAGE_PRESENT | _PAGE_NO_READ | \
+ _page_cachable_default)
+#define PAGE_SHARED __pgprot(_PAGE_PRESENT | _PAGE_WRITE | \
+ __READABLE | _page_cachable_default)
+#define PAGE_COPY __pgprot(_PAGE_PRESENT | _PAGE_NO_EXEC | \
+ __READABLE | _page_cachable_default)
+#define PAGE_READONLY __pgprot(_PAGE_PRESENT | __READABLE | \
+ _page_cachable_default)
+#define PAGE_KERNEL __pgprot(_PAGE_PRESENT | __READABLE | __WRITEABLE | \
+ _PAGE_GLOBAL | _page_cachable_default)
+#define PAGE_KERNEL_NC __pgprot(_PAGE_PRESENT | __READABLE | __WRITEABLE | \
+ _PAGE_GLOBAL | _CACHE_CACHABLE_NONCOHERENT)
+#define PAGE_USERIO __pgprot(_PAGE_PRESENT | _PAGE_WRITE | \
+ _page_cachable_default)
#define PAGE_KERNEL_UNCACHED __pgprot(_PAGE_PRESENT | __READABLE | \
- __WRITEABLE | _PAGE_GLOBAL | _CACHE_UNCACHED)
+ __WRITEABLE | _PAGE_GLOBAL | _CACHE_UNCACHED)

/*
* If _PAGE_NO_EXEC is not defined, we can't do page protection for
@@ -414,8 +414,6 @@ static inline pte_t pte_mkyoung(pte_t pte)
return pte;
}

-#define pte_sw_mkyoung pte_mkyoung
-
#ifdef CONFIG_MIPS_HUGE_TLB_SUPPORT
static inline int pte_huge(pte_t pte) { return pte_val(pte) & _PAGE_HUGE; }

diff --git a/arch/mips/mm/cache.c b/arch/mips/mm/cache.c
index 3e81ba000096..ed75f2871aad 100644
--- a/arch/mips/mm/cache.c
+++ b/arch/mips/mm/cache.c
@@ -159,22 +159,23 @@ static inline void setup_protection_map(void)
{
if (cpu_has_rixi) {
protection_map[0] = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_NO_EXEC | _PAGE_NO_READ);
- protection_map[1] = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_NO_EXEC);
+ protection_map[1] = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_NO_EXEC | __READABLE);
protection_map[2] = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_NO_EXEC | _PAGE_NO_READ);
- protection_map[3] = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_NO_EXEC);
- protection_map[4] = __pgprot(_page_cachable_default | _PAGE_PRESENT);
- protection_map[5] = __pgprot(_page_cachable_default | _PAGE_PRESENT);
- protection_map[6] = __pgprot(_page_cachable_default | _PAGE_PRESENT);
- protection_map[7] = __pgprot(_page_cachable_default | _PAGE_PRESENT);
+ protection_map[3] = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_NO_EXEC | __READABLE);
+ protection_map[4] = __pgprot(_page_cachable_default | _PAGE_PRESENT | __READABLE);
+ protection_map[5] = __pgprot(_page_cachable_default | _PAGE_PRESENT | __READABLE);
+ protection_map[6] = __pgprot(_page_cachable_default | _PAGE_PRESENT | __READABLE);
+ protection_map[7] = __pgprot(_page_cachable_default | _PAGE_PRESENT | __READABLE);

protection_map[8] = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_NO_EXEC | _PAGE_NO_READ);
- protection_map[9] = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_NO_EXEC);
+ protection_map[9] = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_NO_EXEC | __READABLE);
protection_map[10] = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_NO_EXEC | _PAGE_WRITE | _PAGE_NO_READ);
- protection_map[11] = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_NO_EXEC | _PAGE_WRITE);
- protection_map[12] = __pgprot(_page_cachable_default | _PAGE_PRESENT);
- protection_map[13] = __pgprot(_page_cachable_default | _PAGE_PRESENT);
- protection_map[14] = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_WRITE);
- protection_map[15] = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_WRITE);
+ protection_map[11] = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_NO_EXEC | _PAGE_WRITE | __READABLE);
+ protection_map[12] = __pgprot(_page_cachable_default | _PAGE_PRESENT | __READABLE);
+ protection_map[13] = __pgprot(_page_cachable_default | _PAGE_PRESENT | __READABLE);
+ protection_map[14] = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_NO_EXEC | __READABLE);
+ protection_map[15] = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_NO_EXEC | __READABLE);
+

} else {
protection_map[0] = PAGE_NONE;
diff --git a/mm/memory.c b/mm/memory.c
index 602f4283122f..5100ab5bcf77 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -2705,7 +2705,6 @@ static vm_fault_t wp_page_copy(struct vm_fault *vmf)
}
flush_cache_page(vma, vmf->address, pte_pfn(vmf->orig_pte));
entry = mk_pte(new_page, vma->vm_page_prot);
- entry = pte_sw_mkyoung(entry);
entry = maybe_mkwrite(pte_mkdirty(entry), vma);
/*
* Clear the pte entry and flush it first, before updating the
@@ -3386,7 +3385,6 @@ static vm_fault_t do_anonymous_page(struct vm_fault *vmf)
__SetPageUptodate(page);

entry = mk_pte(page, vma->vm_page_prot);
- entry = pte_sw_mkyoung(entry);
if (vma->vm_flags & VM_WRITE)
entry = pte_mkwrite(pte_mkdirty(entry));

@@ -3661,7 +3659,6 @@ vm_fault_t alloc_set_pte(struct vm_fault *vmf, struct page *page)

flush_icache_page(vma, page);
entry = mk_pte(page, vma->vm_page_prot);
- entry = pte_sw_mkyoung(entry);
if (write)
entry = maybe_mkwrite(pte_mkdirty(entry), vma);
/* copy-on-write page */
--
2.17.1