[PATCH v4 06/13] microblaze: use pgtable-nopmd instead of 4level-fixup

Mike Rapoport
2019-11-05T07:16:49Z

microblaze has only two-level page tables and can use pgtable-nopmd and
folding of the upper layers.

Replace usage of include/asm-generic/4level-fixup.h and explicit definition
of __PAGETABLE_PMD_FOLDED in microblaze with
include/asm-generic/pgtable-nopmd.h and adjust page table manipulation
macros and functions accordingly.

Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
---
arch/microblaze/include/asm/page.h | 3 ---
arch/microblaze/include/asm/pgalloc.h | 16 ----------------
arch/microblaze/include/asm/pgtable.h | 32 ++------------------------------
arch/microblaze/kernel/signal.c | 10 +++++++---
arch/microblaze/mm/init.c | 7 +++++--
arch/microblaze/mm/pgtable.c | 13 +++++++++++--
6 files changed, 25 insertions(+), 56 deletions(-)

diff --git a/arch/microblaze/include/asm/page.h b/arch/microblaze/include/asm/page.h
index d506bb0..f4b44b2 100644
--- a/arch/microblaze/include/asm/page.h
+++ b/arch/microblaze/include/asm/page.h
@@ -90,7 +90,6 @@ typedef struct { unsigned long pte; } pte_t;
typedef struct { unsigned long pgprot; } pgprot_t;
/* FIXME this can depend on linux kernel version */
# ifdef CONFIG_MMU
-typedef struct { unsigned long pmd; } pmd_t;
typedef struct { unsigned long pgd; } pgd_t;
# else /* CONFIG_MMU */
typedef struct { unsigned long ste[64]; } pmd_t;
@@ -103,7 +102,6 @@ typedef struct { p4d_t pge[1]; } pgd_t;
# define pgprot_val(x) ((x).pgprot)

# ifdef CONFIG_MMU
-# define pmd_val(x) ((x).pmd)
# define pgd_val(x) ((x).pgd)
# else /* CONFIG_MMU */
# define pmd_val(x) ((x).ste[0])
@@ -112,7 +110,6 @@ typedef struct { p4d_t pge[1]; } pgd_t;
# endif /* CONFIG_MMU */

# define __pte(x) ((pte_t) { (x) })
-# define __pmd(x) ((pmd_t) { (x) })
# define __pgd(x) ((pgd_t) { (x) })
# define __pgprot(x) ((pgprot_t) { (x) })

diff --git a/arch/microblaze/include/asm/pgalloc.h b/arch/microblaze/include/asm/pgalloc.h
index 7ecb05b..fcf1e23 100644
--- a/arch/microblaze/include/asm/pgalloc.h
+++ b/arch/microblaze/include/asm/pgalloc.h
@@ -41,13 +41,6 @@ static inline void free_pgd(pgd_t *pgd)

#define pmd_pgtable(pmd) pmd_page(pmd)

-/*
- * We don't have any real pmd's, and this code never triggers because
- * the pgd will always be present..
- */
-#define pmd_alloc_one_fast(mm, address) ({ BUG(); ((pmd_t *)1); })
-#define pmd_alloc_one(mm, address) ({ BUG(); ((pmd_t *)2); })
-
extern pte_t *pte_alloc_one_kernel(struct mm_struct *mm);

#define __pte_free_tlb(tlb, pte, addr) pte_free((tlb)->mm, (pte))
@@ -58,15 +51,6 @@ extern pte_t *pte_alloc_one_kernel(struct mm_struct *mm);
#define pmd_populate_kernel(mm, pmd, pte) \
(pmd_val(*(pmd)) = (unsigned long) (pte))

-/*
- * We don't have any real pmd's, and this code never triggers because
- * the pgd will always be present..
- */
-#define pmd_alloc_one(mm, address) ({ BUG(); ((pmd_t *)2); })
-#define pmd_free(mm, x) do { } while (0)
-#define __pmd_free_tlb(tlb, x, addr) pmd_free((tlb)->mm, x)
-#define pgd_populate(mm, pmd, pte) BUG()
-
#endif /* CONFIG_MMU */

#endif /* _ASM_MICROBLAZE_PGALLOC_H */
diff --git a/arch/microblaze/include/asm/pgtable.h b/arch/microblaze/include/asm/pgtable.h
index 954b69a..2def331 100644
--- a/arch/microblaze/include/asm/pgtable.h
+++ b/arch/microblaze/include/asm/pgtable.h
@@ -59,9 +59,7 @@ extern int mem_init_done;

#else /* CONFIG_MMU */

-#include <asm-generic/4level-fixup.h>
-
-#define __PAGETABLE_PMD_FOLDED 1
+#include <asm-generic/pgtable-nopmd.h>

#ifdef __KERNEL__
#ifndef __ASSEMBLY__
@@ -138,13 +136,8 @@ static inline pte_t pte_mkspecial(pte_t pte) { return pte; }
*
*/

-/* PMD_SHIFT determines the size of the area mapped by the PTE pages */
-#define PMD_SHIFT (PAGE_SHIFT + PTE_SHIFT)
-#define PMD_SIZE (1UL << PMD_SHIFT)
-#define PMD_MASK (~(PMD_SIZE-1))
-
/* PGDIR_SHIFT determines what a top-level page table entry can map */
-#define PGDIR_SHIFT PMD_SHIFT
+#define PGDIR_SHIFT (PAGE_SHIFT + PTE_SHIFT)
#define PGDIR_SIZE (1UL << PGDIR_SHIFT)
#define PGDIR_MASK (~(PGDIR_SIZE-1))

@@ -165,9 +158,6 @@ static inline pte_t pte_mkspecial(pte_t pte) { return pte; }
#define pte_ERROR(e) \
printk(KERN_ERR "%s:%d: bad pte "PTE_FMT".\n", \
__FILE__, __LINE__, pte_val(e))
-#define pmd_ERROR(e) \
- printk(KERN_ERR "%s:%d: bad pmd %08lx.\n", \
- __FILE__, __LINE__, pmd_val(e))
#define pgd_ERROR(e) \
printk(KERN_ERR "%s:%d: bad pgd %08lx.\n", \
__FILE__, __LINE__, pgd_val(e))
@@ -314,18 +304,6 @@ extern unsigned long empty_zero_page[1024];

#ifndef __ASSEMBLY__
/*
- * The "pgd_xxx()" functions here are trivial for a folded two-level
- * setup: the pgd is never bad, and a pmd always exists (as it's folded
- * into the pgd entry)
- */
-static inline int pgd_none(pgd_t pgd) { return 0; }
-static inline int pgd_bad(pgd_t pgd) { return 0; }
-static inline int pgd_present(pgd_t pgd) { return 1; }
-#define pgd_clear(xp) do { } while (0)
-#define pgd_page(pgd) \
- ((unsigned long) __va(pgd_val(pgd) & PAGE_MASK))
-
-/*
* The following only work if pte_present() is true.
* Undefined behaviour if not..
*/
@@ -479,12 +457,6 @@ static inline void ptep_mkdirty(struct mm_struct *mm,
#define pgd_index(address) ((address) >> PGDIR_SHIFT)
#define pgd_offset(mm, address) ((mm)->pgd + pgd_index(address))

-/* Find an entry in the second-level page table.. */
-static inline pmd_t *pmd_offset(pgd_t *dir, unsigned long address)
-{
- return (pmd_t *) dir;
-}
-
/* Find an entry in the third-level page table.. */
#define pte_index(address) \
(((address) >> PAGE_SHIFT) & (PTRS_PER_PTE - 1))
diff --git a/arch/microblaze/kernel/signal.c b/arch/microblaze/kernel/signal.c
index cdd4feb..c9125c3 100644
--- a/arch/microblaze/kernel/signal.c
+++ b/arch/microblaze/kernel/signal.c
@@ -160,6 +160,9 @@ static int setup_rt_frame(struct ksignal *ksig, sigset_t *set,
int err = 0, sig = ksig->sig;
unsigned long address = 0;
#ifdef CONFIG_MMU
+ pgd_t *pgdp;
+ p4d_t *p4dp;
+ pud_t *pudp;
pmd_t *pmdp;
pte_t *ptep;
#endif
@@ -195,9 +198,10 @@ static int setup_rt_frame(struct ksignal *ksig, sigset_t *set,

address = ((unsigned long)frame->tramp);
#ifdef CONFIG_MMU
- pmdp = pmd_offset(pud_offset(
- pgd_offset(current->mm, address),
- address), address);
+ pgdp = pgd_offset(current->mm, address);
+ p4dp = p4d_offset(pgdp, address);
+ pudp = pud_offset(p4dp, address);
+ pmdp = pmd_offset(pudp, address);

preempt_disable();
ptep = pte_offset_map(pmdp, address);
diff --git a/arch/microblaze/mm/init.c b/arch/microblaze/mm/init.c
index a015a95..050fc62 100644
--- a/arch/microblaze/mm/init.c
+++ b/arch/microblaze/mm/init.c
@@ -53,8 +53,11 @@ EXPORT_SYMBOL(kmap_prot);

static inline pte_t *virt_to_kpte(unsigned long vaddr)
{
- return pte_offset_kernel(pmd_offset(pgd_offset_k(vaddr),
- vaddr), vaddr);
+ pgd_t *pgd = pgd_offset_k(vaddr);
+ p4d_t *p4d = p4d_offset(pgd, vaddr);
+ pud_t *pud = pud_offset(p4d, vaddr);
+
+ return pte_offset_kernel(pmd_offset(pud, vaddr), vaddr);
}

static void __init highmem_init(void)
diff --git a/arch/microblaze/mm/pgtable.c b/arch/microblaze/mm/pgtable.c
index 010bb9c..68c26ca 100644
--- a/arch/microblaze/mm/pgtable.c
+++ b/arch/microblaze/mm/pgtable.c
@@ -134,11 +134,16 @@ EXPORT_SYMBOL(iounmap);

int map_page(unsigned long va, phys_addr_t pa, int flags)
{
+ p4d_t *p4d;
+ pud_t *pud;
pmd_t *pd;
pte_t *pg;
int err = -ENOMEM;
+
/* Use upper 10 bits of VA to index the first level map */
- pd = pmd_offset(pgd_offset_k(va), va);
+ p4d = p4d_offset(pgd_offset_k(va), va);
+ pud = pud_offset(p4d, va);
+ pd = pmd_offset(pud, va);
/* Use middle 10 bits of VA to index the second-level map */
pg = pte_alloc_kernel(pd, va); /* from powerpc - pgtable.c */
/* pg = pte_alloc_kernel(&init_mm, pd, va); */
@@ -188,13 +193,17 @@ void __init mapin_ram(void)
static int get_pteptr(struct mm_struct *mm, unsigned long addr, pte_t **ptep)
{
pgd_t *pgd;
+ p4d_t *p4d;
+ pud_t *pud;
pmd_t *pmd;
pte_t *pte;
int retval = 0;

pgd = pgd_offset(mm, addr & PAGE_MASK);
if (pgd) {
- pmd = pmd_offset(pgd, addr & PAGE_MASK);
+ p4d = p4d_offset(pgd, addr & PAGE_MASK);
+ pud = pud_offset(p4d, addr & PAGE_MASK);
+ pmd = pmd_offset(pud, addr & PAGE_MASK);
if (pmd_present(*pmd)) {
pte = pte_offset_kernel(pmd, addr & PAGE_MASK);
if (pte) {
--
2.7.4