[PATCHv2, RESEND 05/19] ia64: expose number of page table levels on Kconfig level

From: Kirill A. Shutemov
Date: Fri Feb 06 2015 - 09:53:38 EST


We would want to use number of page table level to define mm_struct.
Let's expose it as CONFIG_PGTABLE_LEVELS.

We need to define PGTABLE_LEVELS before sourcing init/Kconfig:
arch/Kconfig will define default value and it's sourced from init/Kconfig.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Cc: Tony Luck <tony.luck@xxxxxxxxx>
Cc: Fenghua Yu <fenghua.yu@xxxxxxxxx>
Tested-by: Guenter Roeck <linux@xxxxxxxxxxxx>
---

I've implemented accounting for pmd page tables as we have for pte (see
mm->nr_ptes). It's requires a new counter in mm_struct: mm->nr_pmds.

But the feature doesn't make any sense if an architecture has PMD level
folded and it would be nice get rid of the counter in this case.

The problem is that we cannot use __PAGETABLE_PMD_FOLDED in
<linux/mm_types.h> due to circular dependencies:

<linux/mm_types> -> <asm/pgtable.h> -> <linux/mm_types.h>

In most cases <asm/pgtable.h> wants <linux/mm_types.h> to get definition
of struct page and struct vm_area_struct. I've tried to split mm_struct
into separate header file to be able to user <asm/pgtable.h> there.

But it doesn't fly on some architectures, like ARM: it wants mm_struct
<asm/pgtable.h> to implement tlb flushing. I don't see how to fix it without
massive de-inlining or coverting a lot for inline functions to macros.

This is other approach: expose number of page tables in use via Kconfig
and use it in <linux/mm_types.h> instead of __PAGETABLE_PMD_FOLDED from
<asm/pgtable.h>.

---
arch/ia64/Kconfig | 18 +++++-------------
arch/ia64/include/asm/page.h | 4 ++--
arch/ia64/include/asm/pgalloc.h | 4 ++--
arch/ia64/include/asm/pgtable.h | 12 ++++++------
arch/ia64/kernel/ivt.S | 12 ++++++------
arch/ia64/kernel/machine_kexec.c | 4 ++--
6 files changed, 23 insertions(+), 31 deletions(-)

diff --git a/arch/ia64/Kconfig b/arch/ia64/Kconfig
index 074e52bf815c..4f9a6661491b 100644
--- a/arch/ia64/Kconfig
+++ b/arch/ia64/Kconfig
@@ -1,3 +1,8 @@
+config PGTABLE_LEVELS
+ int "Page Table Levels" if !IA64_PAGE_SIZE_64KB
+ range 3 4 if !IA64_PAGE_SIZE_64KB
+ default 3
+
source "init/Kconfig"

source "kernel/Kconfig.freezer"
@@ -286,19 +291,6 @@ config IA64_PAGE_SIZE_64KB

endchoice

-choice
- prompt "Page Table Levels"
- default PGTABLE_3
-
-config PGTABLE_3
- bool "3 Levels"
-
-config PGTABLE_4
- depends on !IA64_PAGE_SIZE_64KB
- bool "4 Levels"
-
-endchoice
-
if IA64_HP_SIM
config HZ
default 32
diff --git a/arch/ia64/include/asm/page.h b/arch/ia64/include/asm/page.h
index 1f1bf144fe62..ec48bb9f95e1 100644
--- a/arch/ia64/include/asm/page.h
+++ b/arch/ia64/include/asm/page.h
@@ -173,7 +173,7 @@ get_order (unsigned long size)
*/
typedef struct { unsigned long pte; } pte_t;
typedef struct { unsigned long pmd; } pmd_t;
-#ifdef CONFIG_PGTABLE_4
+#if CONFIG_PGTABLE_LEVELS == 4
typedef struct { unsigned long pud; } pud_t;
#endif
typedef struct { unsigned long pgd; } pgd_t;
@@ -182,7 +182,7 @@ get_order (unsigned long size)

# define pte_val(x) ((x).pte)
# define pmd_val(x) ((x).pmd)
-#ifdef CONFIG_PGTABLE_4
+#if CONFIG_PGTABLE_LEVELS == 4
# define pud_val(x) ((x).pud)
#endif
# define pgd_val(x) ((x).pgd)
diff --git a/arch/ia64/include/asm/pgalloc.h b/arch/ia64/include/asm/pgalloc.h
index 5767cdfc08db..f5e70e961948 100644
--- a/arch/ia64/include/asm/pgalloc.h
+++ b/arch/ia64/include/asm/pgalloc.h
@@ -32,7 +32,7 @@ static inline void pgd_free(struct mm_struct *mm, pgd_t *pgd)
quicklist_free(0, NULL, pgd);
}

-#ifdef CONFIG_PGTABLE_4
+#if CONFIG_PGTABLE_LEVELS == 4
static inline void
pgd_populate(struct mm_struct *mm, pgd_t * pgd_entry, pud_t * pud)
{
@@ -49,7 +49,7 @@ static inline void pud_free(struct mm_struct *mm, pud_t *pud)
quicklist_free(0, NULL, pud);
}
#define __pud_free_tlb(tlb, pud, address) pud_free((tlb)->mm, pud)
-#endif /* CONFIG_PGTABLE_4 */
+#endif /* CONFIG_PGTABLE_LEVELS == 4 */

static inline void
pud_populate(struct mm_struct *mm, pud_t * pud_entry, pmd_t * pmd)
diff --git a/arch/ia64/include/asm/pgtable.h b/arch/ia64/include/asm/pgtable.h
index 7b6f8801df57..9f3ed9ee8f13 100644
--- a/arch/ia64/include/asm/pgtable.h
+++ b/arch/ia64/include/asm/pgtable.h
@@ -99,7 +99,7 @@
#define PMD_MASK (~(PMD_SIZE-1))
#define PTRS_PER_PMD (1UL << (PTRS_PER_PTD_SHIFT))

-#ifdef CONFIG_PGTABLE_4
+#if CONFIG_PGTABLE_LEVELS == 4
/*
* Definitions for second level:
*
@@ -117,7 +117,7 @@
*
* PGDIR_SHIFT determines what a first-level page table entry can map.
*/
-#ifdef CONFIG_PGTABLE_4
+#if CONFIG_PGTABLE_LEVELS == 4
#define PGDIR_SHIFT (PUD_SHIFT + (PTRS_PER_PTD_SHIFT))
#else
#define PGDIR_SHIFT (PMD_SHIFT + (PTRS_PER_PTD_SHIFT))
@@ -180,7 +180,7 @@
#define __S111 __pgprot(__ACCESS_BITS | _PAGE_PL_3 | _PAGE_AR_RWX)

#define pgd_ERROR(e) printk("%s:%d: bad pgd %016lx.\n", __FILE__, __LINE__, pgd_val(e))
-#ifdef CONFIG_PGTABLE_4
+#if CONFIG_PGTABLE_LEVELS == 4
#define pud_ERROR(e) printk("%s:%d: bad pud %016lx.\n", __FILE__, __LINE__, pud_val(e))
#endif
#define pmd_ERROR(e) printk("%s:%d: bad pmd %016lx.\n", __FILE__, __LINE__, pmd_val(e))
@@ -281,7 +281,7 @@ extern unsigned long VMALLOC_END;
#define pud_page_vaddr(pud) ((unsigned long) __va(pud_val(pud) & _PFN_MASK))
#define pud_page(pud) virt_to_page((pud_val(pud) + PAGE_OFFSET))

-#ifdef CONFIG_PGTABLE_4
+#if CONFIG_PGTABLE_LEVELS == 4
#define pgd_none(pgd) (!pgd_val(pgd))
#define pgd_bad(pgd) (!ia64_phys_addr_valid(pgd_val(pgd)))
#define pgd_present(pgd) (pgd_val(pgd) != 0UL)
@@ -384,7 +384,7 @@ pgd_offset (const struct mm_struct *mm, unsigned long address)
here. */
#define pgd_offset_gate(mm, addr) pgd_offset_k(addr)

-#ifdef CONFIG_PGTABLE_4
+#if CONFIG_PGTABLE_LEVELS == 4
/* Find an entry in the second-level page table.. */
#define pud_offset(dir,addr) \
((pud_t *) pgd_page_vaddr(*(dir)) + (((addr) >> PUD_SHIFT) & (PTRS_PER_PUD - 1)))
@@ -586,7 +586,7 @@ extern struct page *zero_page_memmap_ptr;
#define __HAVE_ARCH_PGD_OFFSET_GATE


-#ifndef CONFIG_PGTABLE_4
+#if CONFIG_PGTABLE_LEVELS == 3
#include <asm-generic/pgtable-nopud.h>
#endif
#include <asm-generic/pgtable.h>
diff --git a/arch/ia64/kernel/ivt.S b/arch/ia64/kernel/ivt.S
index 18e794a57248..e42bf7a913f3 100644
--- a/arch/ia64/kernel/ivt.S
+++ b/arch/ia64/kernel/ivt.S
@@ -146,7 +146,7 @@ ENTRY(vhpt_miss)
(p6) dep r17=r18,r19,3,(PAGE_SHIFT-3) // r17=pgd_offset for region 5
(p7) dep r17=r18,r17,3,(PAGE_SHIFT-6) // r17=pgd_offset for region[0-4]
cmp.eq p7,p6=0,r21 // unused address bits all zeroes?
-#ifdef CONFIG_PGTABLE_4
+#if CONFIG_PGTABLE_LEVELS == 4
shr.u r28=r22,PUD_SHIFT // shift pud index into position
#else
shr.u r18=r22,PMD_SHIFT // shift pmd index into position
@@ -155,7 +155,7 @@ ENTRY(vhpt_miss)
ld8 r17=[r17] // get *pgd (may be 0)
;;
(p7) cmp.eq p6,p7=r17,r0 // was pgd_present(*pgd) == NULL?
-#ifdef CONFIG_PGTABLE_4
+#if CONFIG_PGTABLE_LEVELS == 4
dep r28=r28,r17,3,(PAGE_SHIFT-3) // r28=pud_offset(pgd,addr)
;;
shr.u r18=r22,PMD_SHIFT // shift pmd index into position
@@ -222,13 +222,13 @@ ENTRY(vhpt_miss)
*/
ld8 r25=[r21] // read *pte again
ld8 r26=[r17] // read *pmd again
-#ifdef CONFIG_PGTABLE_4
+#if CONFIG_PGTABLE_LEVELS == 4
ld8 r19=[r28] // read *pud again
#endif
cmp.ne p6,p7=r0,r0
;;
cmp.ne.or.andcm p6,p7=r26,r20 // did *pmd change
-#ifdef CONFIG_PGTABLE_4
+#if CONFIG_PGTABLE_LEVELS == 4
cmp.ne.or.andcm p6,p7=r19,r29 // did *pud change
#endif
mov r27=PAGE_SHIFT<<2
@@ -476,7 +476,7 @@ ENTRY(nested_dtlb_miss)
(p6) dep r17=r18,r19,3,(PAGE_SHIFT-3) // r17=pgd_offset for region 5
(p7) dep r17=r18,r17,3,(PAGE_SHIFT-6) // r17=pgd_offset for region[0-4]
cmp.eq p7,p6=0,r21 // unused address bits all zeroes?
-#ifdef CONFIG_PGTABLE_4
+#if CONFIG_PGTABLE_LEVELS == 4
shr.u r18=r22,PUD_SHIFT // shift pud index into position
#else
shr.u r18=r22,PMD_SHIFT // shift pmd index into position
@@ -487,7 +487,7 @@ ENTRY(nested_dtlb_miss)
(p7) cmp.eq p6,p7=r17,r0 // was pgd_present(*pgd) == NULL?
dep r17=r18,r17,3,(PAGE_SHIFT-3) // r17=p[u|m]d_offset(pgd,addr)
;;
-#ifdef CONFIG_PGTABLE_4
+#if CONFIG_PGTABLE_LEVELS == 4
(p7) ld8 r17=[r17] // get *pud (may be 0)
shr.u r18=r22,PMD_SHIFT // shift pmd index into position
;;
diff --git a/arch/ia64/kernel/machine_kexec.c b/arch/ia64/kernel/machine_kexec.c
index 5151a649c96b..b72cd7a07222 100644
--- a/arch/ia64/kernel/machine_kexec.c
+++ b/arch/ia64/kernel/machine_kexec.c
@@ -156,9 +156,9 @@ void arch_crash_save_vmcoreinfo(void)
VMCOREINFO_OFFSET(node_memblk_s, start_paddr);
VMCOREINFO_OFFSET(node_memblk_s, size);
#endif
-#ifdef CONFIG_PGTABLE_3
+#if CONFIG_PGTABLE_LEVELS == 3
VMCOREINFO_CONFIG(PGTABLE_3);
-#elif defined(CONFIG_PGTABLE_4)
+#elif CONFIG_PGTABLE_LEVELS == 4
VMCOREINFO_CONFIG(PGTABLE_4);
#endif
}
--
2.1.4

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