[PATCH v2 06/14] powerpc/nohash32: allow setting GUARDED attribute in the PMD directly

From: Christophe Leroy
Date: Wed May 16 2018 - 05:36:26 EST

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In reply to: Christophe Leroy: "[PATCH v2 09/14] powerpc/mm: Use hardware assistance in TLB handlers on the 8xx"
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On the 8xx, the GUARDED attribute of the pages is managed in the
L1 entry, therefore to avoid having to copy it into L1 entry
at each TLB miss, we have to set it in the PMD

In order to allow this, this patch splits the VM alloc space in two
parts, one for VM alloc and non Guarded IO, and one for Guarded IO.

Signed-off-by: Christophe Leroy <christophe.leroy@xxxxxx>
---
arch/powerpc/include/asm/nohash/32/pgalloc.h | 12 ++++++++++++
arch/powerpc/include/asm/nohash/32/pgtable.h | 18 ++++++++++++++++--
arch/powerpc/mm/dump_linuxpagetables.c | 26 ++++++++++++++++++++++++--
arch/powerpc/mm/ioremap.c | 13 ++++++++++---
arch/powerpc/mm/mem.c | 9 +++++++++
arch/powerpc/mm/pgtable_32.c | 28 +++++++++++++++++++++++++++-
arch/powerpc/platforms/Kconfig.cputype | 2 ++
7 files changed, 100 insertions(+), 8 deletions(-)

diff --git a/arch/powerpc/include/asm/nohash/32/pgalloc.h b/arch/powerpc/include/asm/nohash/32/pgalloc.h
index 29d37bd1f3b3..81c19d6460bd 100644
--- a/arch/powerpc/include/asm/nohash/32/pgalloc.h
+++ b/arch/powerpc/include/asm/nohash/32/pgalloc.h
@@ -58,6 +58,14 @@ static inline void pmd_populate_kernel(struct mm_struct *mm, pmd_t *pmdp,
*pmdp = __pmd(__pa(pte) | _PMD_PRESENT);
}

+#ifdef CONFIG_PPC_GUARDED_PAGE_IN_PMD
+static inline void pmd_populate_kernel_g(struct mm_struct *mm, pmd_t *pmdp,
+ pte_t *pte)
+{
+ *pmdp = __pmd(__pa(pte) | _PMD_PRESENT | _PMD_GUARDED);
+}
+#endif
+
static inline void pmd_populate(struct mm_struct *mm, pmd_t *pmdp,
pgtable_t pte_page)
{
@@ -83,6 +91,10 @@ static inline void pmd_populate(struct mm_struct *mm, pmd_t *pmdp,
#define pmd_pgtable(pmd) pmd_page(pmd)
#endif

+#define pte_alloc_kernel_g(pmd, address) \
+ ((unlikely(pmd_none(*(pmd))) && __pte_alloc_kernel_g(pmd, address))? \
+ NULL: pte_offset_kernel(pmd, address))
+
extern pte_t *pte_alloc_one_kernel(struct mm_struct *mm, unsigned long addr);
extern pgtable_t pte_alloc_one(struct mm_struct *mm, unsigned long addr);

diff --git a/arch/powerpc/include/asm/nohash/32/pgtable.h b/arch/powerpc/include/asm/nohash/32/pgtable.h
index 810945afe677..7873722198e1 100644
--- a/arch/powerpc/include/asm/nohash/32/pgtable.h
+++ b/arch/powerpc/include/asm/nohash/32/pgtable.h
@@ -80,9 +80,14 @@ extern int icache_44x_need_flush;
#else
#define PKMAP_BASE ((FIXADDR_START - PAGE_SIZE*(LAST_PKMAP + 1)) & PMD_MASK)
#endif
-#define KVIRT_TOP PKMAP_BASE
+#define _KVIRT_TOP PKMAP_BASE
#else
-#define KVIRT_TOP (0xfe000000UL) /* for now, could be FIXMAP_BASE ? */
+#define _KVIRT_TOP (0xfe000000UL) /* for now, could be FIXMAP_BASE ? */
+#endif
+#ifdef CONFIG_PPC_GUARDED_PAGE_IN_PMD
+#define KVIRT_TOP _ALIGN_DOWN(_KVIRT_TOP, PGDIR_SIZE)
+#else
+#define KVIRT_TOP _KVIRT_TOP
#endif

/*
@@ -95,7 +100,11 @@ extern int icache_44x_need_flush;
#else
#define IOREMAP_END KVIRT_TOP
#endif
+#ifdef CONFIG_PPC_GUARDED_PAGE_IN_PMD
+#define IOREMAP_BASE _ALIGN_UP(VMALLOC_BASE + (IOREMAP_END - VMALLOC_BASE) / 2, PGDIR_SIZE)
+#else
#define IOREMAP_BASE VMALLOC_BASE
+#endif

/*
* Just any arbitrary offset to the start of the vmalloc VM area: the
@@ -114,8 +123,13 @@ extern int icache_44x_need_flush;
#else
#define VMALLOC_BASE _ALIGN_DOWN((long)high_memory + VMALLOC_OFFSET, VMALLOC_OFFSET)
#endif
+#ifdef CONFIG_PPC_GUARDED_PAGE_IN_PMD
+#define VMALLOC_START VMALLOC_BASE
+#define VMALLOC_END IOREMAP_BASE
+#else
#define VMALLOC_START ioremap_bot
#define VMALLOC_END IOREMAP_END
+#endif

/*
* Bits in a linux-style PTE. These match the bits in the
diff --git a/arch/powerpc/mm/dump_linuxpagetables.c b/arch/powerpc/mm/dump_linuxpagetables.c
index 6022adb899b7..cd3797be5e05 100644
--- a/arch/powerpc/mm/dump_linuxpagetables.c
+++ b/arch/powerpc/mm/dump_linuxpagetables.c
@@ -74,9 +74,9 @@ struct addr_marker {

static struct addr_marker address_markers[] = {
{ 0, "Start of kernel VM" },
+#ifdef CONFIG_PPC64
{ 0, "vmalloc() Area" },
{ 0, "vmalloc() End" },
-#ifdef CONFIG_PPC64
{ 0, "isa I/O start" },
{ 0, "isa I/O end" },
{ 0, "phb I/O start" },
@@ -85,8 +85,19 @@ static struct addr_marker address_markers[] = {
{ 0, "I/O remap end" },
{ 0, "vmemmap start" },
#else
+#ifdef CONFIG_PPC_GUARDED_PAGE_IN_PMD
+ { 0, "vmalloc() Area" },
+ { 0, "vmalloc() End" },
{ 0, "Early I/O remap start" },
{ 0, "Early I/O remap end" },
+ { 0, "I/O remap start" },
+ { 0, "I/O remap end" },
+#else
+ { 0, "Early I/O remap start" },
+ { 0, "Early I/O remap end" },
+ { 0, "vmalloc() I/O remap start" },
+ { 0, "vmalloc() I/O remap end" },
+#endif
#ifdef CONFIG_NOT_COHERENT_CACHE
{ 0, "Consistent mem start" },
{ 0, "Consistent mem end" },
@@ -437,9 +448,9 @@ static void populate_markers(void)
int i = 0;

address_markers[i++].start_address = PAGE_OFFSET;
+#ifdef CONFIG_PPC64
address_markers[i++].start_address = VMALLOC_START;
address_markers[i++].start_address = VMALLOC_END;
-#ifdef CONFIG_PPC64
address_markers[i++].start_address = ISA_IO_BASE;
address_markers[i++].start_address = ISA_IO_END;
address_markers[i++].start_address = PHB_IO_BASE;
@@ -452,8 +463,19 @@ static void populate_markers(void)
address_markers[i++].start_address = VMEMMAP_BASE;
#endif
#else /* !CONFIG_PPC64 */
+#ifdef CONFIG_PPC_GUARDED_PAGE_IN_PMD
+ address_markers[i++].start_address = VMALLOC_START;
+ address_markers[i++].start_address = VMALLOC_END;
address_markers[i++].start_address = IOREMAP_BASE;
address_markers[i++].start_address = ioremap_bot;
+ address_markers[i++].start_address = ioremap_bot;
+ address_markers[i++].start_address = IOREMAP_END;
+#else
+ address_markers[i++].start_address = IOREMAP_BASE;
+ address_markers[i++].start_address = ioremap_bot;
+ address_markers[i++].start_address = ioremap_bot;
+ address_markers[i++].start_address = IOREMAP_END;
+#endif
#ifdef CONFIG_NOT_COHERENT_CACHE
address_markers[i++].start_address = IOREMAP_END;
address_markers[i++].start_address = IOREMAP_END +
diff --git a/arch/powerpc/mm/ioremap.c b/arch/powerpc/mm/ioremap.c
index a140feec2f8a..3eecf82ff93e 100644
--- a/arch/powerpc/mm/ioremap.c
+++ b/arch/powerpc/mm/ioremap.c
@@ -134,9 +134,16 @@ void __iomem * __ioremap_caller(phys_addr_t addr, unsigned long size,
if (slab_is_available()) {
struct vm_struct *area;

- area = __get_vm_area_caller(size, VM_IOREMAP,
- ioremap_bot, IOREMAP_END,
- caller);
+#ifdef CONFIG_PPC_GUARDED_PAGE_IN_PMD
+ if (!(flags & _PAGE_GUARDED))
+ area = __get_vm_area_caller(size, VM_IOREMAP,
+ VMALLOC_START, VMALLOC_END,
+ caller);
+ else
+#endif
+ area = __get_vm_area_caller(size, VM_IOREMAP,
+ ioremap_bot, IOREMAP_END,
+ caller);
if (area == NULL)
return NULL;

diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c
index b680aa78a4ac..fd7af7af5b58 100644
--- a/arch/powerpc/mm/mem.c
+++ b/arch/powerpc/mm/mem.c
@@ -386,10 +386,19 @@ void __init mem_init(void)
pr_info(" * 0x%08lx..0x%08lx : consistent mem\n",
IOREMAP_END, IOREMAP_END + CONFIG_CONSISTENT_SIZE);
#endif /* CONFIG_NOT_COHERENT_CACHE */
+#ifdef CONFIG_PPC_GUARDED_PAGE_IN_PMD
+ pr_info(" * 0x%08lx..0x%08lx : ioremap\n",
+ ioremap_bot, IOREMAP_END);
pr_info(" * 0x%08lx..0x%08lx : early ioremap\n",
IOREMAP_BASE, ioremap_bot);
+ pr_info(" * 0x%08lx..0x%08lx : vmalloc\n",
+ VMALLOC_START, VMALLOC_END);
+#else
pr_info(" * 0x%08lx..0x%08lx : vmalloc & ioremap\n",
VMALLOC_START, VMALLOC_END);
+ pr_info(" * 0x%08lx..0x%08lx : early ioremap\n",
+ IOREMAP_BASE, ioremap_bot);
+#endif
#endif /* CONFIG_PPC32 */
}

diff --git a/arch/powerpc/mm/pgtable_32.c b/arch/powerpc/mm/pgtable_32.c
index 54a5bc0767a9..3aa0c78db95d 100644
--- a/arch/powerpc/mm/pgtable_32.c
+++ b/arch/powerpc/mm/pgtable_32.c
@@ -70,6 +70,27 @@ pgtable_t pte_alloc_one(struct mm_struct *mm, unsigned long address)
return ptepage;
}

+#ifdef CONFIG_PPC_GUARDED_PAGE_IN_PMD
+int __pte_alloc_kernel_g(pmd_t *pmd, unsigned long address)
+{
+ pte_t *new = pte_alloc_one_kernel(&init_mm, address);
+ if (!new)
+ return -ENOMEM;
+
+ smp_wmb(); /* See comment in __pte_alloc */
+
+ spin_lock(&init_mm.page_table_lock);
+ if (likely(pmd_none(*pmd))) { /* Has another populated it ? */
+ pmd_populate_kernel_g(&init_mm, pmd, new);
+ new = NULL;
+ }
+ spin_unlock(&init_mm.page_table_lock);
+ if (new)
+ pte_free_kernel(&init_mm, new);
+ return 0;
+}
+#endif
+
int map_kernel_page(unsigned long va, phys_addr_t pa, int flags)
{
pmd_t *pd;
@@ -79,7 +100,12 @@ int map_kernel_page(unsigned long va, phys_addr_t pa, int flags)
/* Use upper 10 bits of VA to index the first level map */
pd = pmd_offset(pud_offset(pgd_offset_k(va), va), va);
/* Use middle 10 bits of VA to index the second-level map */
- pg = pte_alloc_kernel(pd, va);
+#ifdef CONFIG_PPC_GUARDED_PAGE_IN_PMD
+ if (flags & _PAGE_GUARDED)
+ pg = pte_alloc_kernel_g(pd, va);
+ else
+#endif
+ pg = pte_alloc_kernel(pd, va);
if (pg != 0) {
err = 0;
/* The PTE should never be already set nor present in the
diff --git a/arch/powerpc/platforms/Kconfig.cputype b/arch/powerpc/platforms/Kconfig.cputype
index 67d3125d0610..ba6b4c86b637 100644
--- a/arch/powerpc/platforms/Kconfig.cputype
+++ b/arch/powerpc/platforms/Kconfig.cputype
@@ -319,6 +319,8 @@ config ARCH_ENABLE_HUGEPAGE_MIGRATION
def_bool y
depends on PPC_BOOK3S_64 && HUGETLB_PAGE && MIGRATION

+config PPC_GUARDED_PAGE_IN_PMD
+ bool

config PPC_MMU_NOHASH
def_bool y
--
2.13.3

Next message: James Morse: "Re: [PATCH v9 07/11] arm64: kexec_file: add crash dump support"
Previous message: Sebastian Andrzej Siewior: "Re: [PATCH v1 0/3] console, serial8250: Disable PM and DMA ops"
In reply to: Christophe Leroy: "[PATCH v2 09/14] powerpc/mm: Use hardware assistance in TLB handlers on the 8xx"
Next in thread: Christophe Leroy: "[PATCH v2 05/14] powerpc: use _ALIGN_DOWN macro for VMALLOC_BASE"
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