[tip: locking/kcsan] sparc32: mm: Restructure sparc32 MMU page-table layout
From: tip-bot2 for Will Deacon
Date: Tue May 12 2020 - 10:37:40 EST
The following commit has been merged into the locking/kcsan branch of tip:
Commit-ID: 3408974d0533e1e9bd6345610b335c7c52195a49
Gitweb: https://git.kernel.org/tip/3408974d0533e1e9bd6345610b335c7c52195a49
Author: Will Deacon <will@xxxxxxxxxx>
AuthorDate: Mon, 11 May 2020 21:41:34 +01:00
Committer: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitterDate: Tue, 12 May 2020 11:04:09 +02:00
sparc32: mm: Restructure sparc32 MMU page-table layout
The "SRMMU" supports 4k pages using a fixed three-level walk with a
256-entry PGD and 64-entry PMD/PTE levels. In order to fill a page
with a 'pgtable_t', the SRMMU code allocates four native PTE tables
into a single PTE allocation and similarly for the PMD level, leading
to an array of 16 physical pointers in a 'pmd_t'
This breaks the generic code which assumes READ_ONCE(*pmd) will be
word sized.
In a manner similar to ef22d8abd876 ("m68k: mm: Restructure Motorola MMU
page-table layout"), implement the native page-table setup directly. This
significantly increases the page-table memory overhead, but will be
addressed in a subsequent patch.
Signed-off-by: Will Deacon <will@xxxxxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Acked-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Cc: "David S. Miller" <davem@xxxxxxxxxxxxx>
Link: https://lkml.kernel.org/r/20200511204150.27858-3-will@xxxxxxxxxx
---
arch/sparc/include/asm/page_32.h | 10 ++---
arch/sparc/include/asm/pgalloc_32.h | 5 +-
arch/sparc/include/asm/pgtable_32.h | 29 +++++++-------
arch/sparc/include/asm/pgtsrmmu.h | 36 +----------------
arch/sparc/include/asm/viking.h | 5 +-
arch/sparc/kernel/head_32.S | 8 ++--
arch/sparc/mm/hypersparc.S | 3 +-
arch/sparc/mm/srmmu.c | 60 +++++++++-------------------
arch/sparc/mm/viking.S | 5 +-
9 files changed, 58 insertions(+), 103 deletions(-)
diff --git a/arch/sparc/include/asm/page_32.h b/arch/sparc/include/asm/page_32.h
index 4782600..da01c8c 100644
--- a/arch/sparc/include/asm/page_32.h
+++ b/arch/sparc/include/asm/page_32.h
@@ -54,7 +54,7 @@ extern struct sparc_phys_banks sp_banks[SPARC_PHYS_BANKS+1];
*/
typedef struct { unsigned long pte; } pte_t;
typedef struct { unsigned long iopte; } iopte_t;
-typedef struct { unsigned long pmdv[16]; } pmd_t;
+typedef struct { unsigned long pmd; } pmd_t;
typedef struct { unsigned long pgd; } pgd_t;
typedef struct { unsigned long ctxd; } ctxd_t;
typedef struct { unsigned long pgprot; } pgprot_t;
@@ -62,7 +62,7 @@ typedef struct { unsigned long iopgprot; } iopgprot_t;
#define pte_val(x) ((x).pte)
#define iopte_val(x) ((x).iopte)
-#define pmd_val(x) ((x).pmdv[0])
+#define pmd_val(x) ((x).pmd)
#define pgd_val(x) ((x).pgd)
#define ctxd_val(x) ((x).ctxd)
#define pgprot_val(x) ((x).pgprot)
@@ -82,7 +82,7 @@ typedef struct { unsigned long iopgprot; } iopgprot_t;
*/
typedef unsigned long pte_t;
typedef unsigned long iopte_t;
-typedef struct { unsigned long pmdv[16]; } pmd_t;
+typedef unsigned long pmd_t;
typedef unsigned long pgd_t;
typedef unsigned long ctxd_t;
typedef unsigned long pgprot_t;
@@ -90,14 +90,14 @@ typedef unsigned long iopgprot_t;
#define pte_val(x) (x)
#define iopte_val(x) (x)
-#define pmd_val(x) ((x).pmdv[0])
+#define pmd_val(x) (x)
#define pgd_val(x) (x)
#define ctxd_val(x) (x)
#define pgprot_val(x) (x)
#define iopgprot_val(x) (x)
#define __pte(x) (x)
-#define __pmd(x) ((pmd_t) { { (x) }, })
+#define __pmd(x) (x)
#define __iopte(x) (x)
#define __pgd(x) (x)
#define __ctxd(x) (x)
diff --git a/arch/sparc/include/asm/pgalloc_32.h b/arch/sparc/include/asm/pgalloc_32.h
index eae0c92..99c0324 100644
--- a/arch/sparc/include/asm/pgalloc_32.h
+++ b/arch/sparc/include/asm/pgalloc_32.h
@@ -60,13 +60,14 @@ pgtable_t pte_alloc_one(struct mm_struct *mm);
static inline pte_t *pte_alloc_one_kernel(struct mm_struct *mm)
{
- return srmmu_get_nocache(PTE_SIZE, PTE_SIZE);
+ return srmmu_get_nocache(SRMMU_PTE_TABLE_SIZE,
+ SRMMU_PTE_TABLE_SIZE);
}
static inline void free_pte_fast(pte_t *pte)
{
- srmmu_free_nocache(pte, PTE_SIZE);
+ srmmu_free_nocache(pte, SRMMU_PTE_TABLE_SIZE);
}
#define pte_free_kernel(mm, pte) free_pte_fast(pte)
diff --git a/arch/sparc/include/asm/pgtable_32.h b/arch/sparc/include/asm/pgtable_32.h
index 0de659a..3367e2b 100644
--- a/arch/sparc/include/asm/pgtable_32.h
+++ b/arch/sparc/include/asm/pgtable_32.h
@@ -11,6 +11,16 @@
#include <linux/const.h>
+#define PMD_SHIFT 18
+#define PMD_SIZE (1UL << PMD_SHIFT)
+#define PMD_MASK (~(PMD_SIZE-1))
+#define PMD_ALIGN(__addr) (((__addr) + ~PMD_MASK) & PMD_MASK)
+
+#define PGDIR_SHIFT 24
+#define PGDIR_SIZE (1UL << PGDIR_SHIFT)
+#define PGDIR_MASK (~(PGDIR_SIZE-1))
+#define PGDIR_ALIGN(__addr) (((__addr) + ~PGDIR_MASK) & PGDIR_MASK)
+
#ifndef __ASSEMBLY__
#include <asm-generic/pgtable-nopud.h>
@@ -34,17 +44,10 @@ unsigned long __init bootmem_init(unsigned long *pages_avail);
#define pmd_ERROR(e) __builtin_trap()
#define pgd_ERROR(e) __builtin_trap()
-#define PMD_SHIFT 22
-#define PMD_SIZE (1UL << PMD_SHIFT)
-#define PMD_MASK (~(PMD_SIZE-1))
-#define PMD_ALIGN(__addr) (((__addr) + ~PMD_MASK) & PMD_MASK)
-#define PGDIR_SHIFT SRMMU_PGDIR_SHIFT
-#define PGDIR_SIZE SRMMU_PGDIR_SIZE
-#define PGDIR_MASK SRMMU_PGDIR_MASK
-#define PTRS_PER_PTE 1024
-#define PTRS_PER_PMD SRMMU_PTRS_PER_PMD
-#define PTRS_PER_PGD SRMMU_PTRS_PER_PGD
-#define USER_PTRS_PER_PGD PAGE_OFFSET / SRMMU_PGDIR_SIZE
+#define PTRS_PER_PTE 64
+#define PTRS_PER_PMD 64
+#define PTRS_PER_PGD 256
+#define USER_PTRS_PER_PGD PAGE_OFFSET / PGDIR_SIZE
#define FIRST_USER_ADDRESS 0UL
#define PTE_SIZE (PTRS_PER_PTE*4)
@@ -179,9 +182,7 @@ static inline int pmd_none(pmd_t pmd)
static inline void pmd_clear(pmd_t *pmdp)
{
- int i;
- for (i = 0; i < PTRS_PER_PTE/SRMMU_REAL_PTRS_PER_PTE; i++)
- set_pte((pte_t *)&pmdp->pmdv[i], __pte(0));
+ set_pte((pte_t *)&pmd_val(*pmdp), __pte(0));
}
static inline int pud_none(pud_t pud)
diff --git a/arch/sparc/include/asm/pgtsrmmu.h b/arch/sparc/include/asm/pgtsrmmu.h
index 32a5088..58ea8e8 100644
--- a/arch/sparc/include/asm/pgtsrmmu.h
+++ b/arch/sparc/include/asm/pgtsrmmu.h
@@ -17,39 +17,9 @@
/* Number of contexts is implementation-dependent; 64k is the most we support */
#define SRMMU_MAX_CONTEXTS 65536
-/* PMD_SHIFT determines the size of the area a second-level page table entry can map */
-#define SRMMU_REAL_PMD_SHIFT 18
-#define SRMMU_REAL_PMD_SIZE (1UL << SRMMU_REAL_PMD_SHIFT)
-#define SRMMU_REAL_PMD_MASK (~(SRMMU_REAL_PMD_SIZE-1))
-#define SRMMU_REAL_PMD_ALIGN(__addr) (((__addr)+SRMMU_REAL_PMD_SIZE-1)&SRMMU_REAL_PMD_MASK)
-
-/* PGDIR_SHIFT determines what a third-level page table entry can map */
-#define SRMMU_PGDIR_SHIFT 24
-#define SRMMU_PGDIR_SIZE (1UL << SRMMU_PGDIR_SHIFT)
-#define SRMMU_PGDIR_MASK (~(SRMMU_PGDIR_SIZE-1))
-#define SRMMU_PGDIR_ALIGN(addr) (((addr)+SRMMU_PGDIR_SIZE-1)&SRMMU_PGDIR_MASK)
-
-#define SRMMU_REAL_PTRS_PER_PTE 64
-#define SRMMU_REAL_PTRS_PER_PMD 64
-#define SRMMU_PTRS_PER_PGD 256
-
-#define SRMMU_REAL_PTE_TABLE_SIZE (SRMMU_REAL_PTRS_PER_PTE*4)
-#define SRMMU_PMD_TABLE_SIZE (SRMMU_REAL_PTRS_PER_PMD*4)
-#define SRMMU_PGD_TABLE_SIZE (SRMMU_PTRS_PER_PGD*4)
-
-/*
- * To support pagetables in highmem, Linux introduces APIs which
- * return struct page* and generally manipulate page tables when
- * they are not mapped into kernel space. Our hardware page tables
- * are smaller than pages. We lump hardware tabes into big, page sized
- * software tables.
- *
- * PMD_SHIFT determines the size of the area a second-level page table entry
- * can map, and our pmd_t is 16 times larger than normal. The values which
- * were once defined here are now generic for 4c and srmmu, so they're
- * found in pgtable.h.
- */
-#define SRMMU_PTRS_PER_PMD 4
+#define SRMMU_PTE_TABLE_SIZE (PAGE_SIZE)
+#define SRMMU_PMD_TABLE_SIZE (PAGE_SIZE)
+#define SRMMU_PGD_TABLE_SIZE (PTRS_PER_PGD*4)
/* Definition of the values in the ET field of PTD's and PTE's */
#define SRMMU_ET_MASK 0x3
diff --git a/arch/sparc/include/asm/viking.h b/arch/sparc/include/asm/viking.h
index 0bbefd1..08ffc60 100644
--- a/arch/sparc/include/asm/viking.h
+++ b/arch/sparc/include/asm/viking.h
@@ -10,6 +10,7 @@
#include <asm/asi.h>
#include <asm/mxcc.h>
+#include <asm/pgtable.h>
#include <asm/pgtsrmmu.h>
/* Bits in the SRMMU control register for GNU/Viking modules.
@@ -227,7 +228,7 @@ static inline unsigned long viking_hwprobe(unsigned long vaddr)
: "=r" (val)
: "r" (vaddr | 0x200), "i" (ASI_M_FLUSH_PROBE));
if ((val & SRMMU_ET_MASK) == SRMMU_ET_PTE) {
- vaddr &= ~SRMMU_PGDIR_MASK;
+ vaddr &= ~PGDIR_MASK;
vaddr >>= PAGE_SHIFT;
return val | (vaddr << 8);
}
@@ -237,7 +238,7 @@ static inline unsigned long viking_hwprobe(unsigned long vaddr)
: "=r" (val)
: "r" (vaddr | 0x100), "i" (ASI_M_FLUSH_PROBE));
if ((val & SRMMU_ET_MASK) == SRMMU_ET_PTE) {
- vaddr &= ~SRMMU_REAL_PMD_MASK;
+ vaddr &= ~PMD_MASK;
vaddr >>= PAGE_SHIFT;
return val | (vaddr << 8);
}
diff --git a/arch/sparc/kernel/head_32.S b/arch/sparc/kernel/head_32.S
index e55f2c0..be30c8d 100644
--- a/arch/sparc/kernel/head_32.S
+++ b/arch/sparc/kernel/head_32.S
@@ -24,7 +24,7 @@
#include <asm/winmacro.h>
#include <asm/thread_info.h> /* TI_UWINMASK */
#include <asm/errno.h>
-#include <asm/pgtsrmmu.h> /* SRMMU_PGDIR_SHIFT */
+#include <asm/pgtable.h> /* PGDIR_SHIFT */
#include <asm/export.h>
.data
@@ -273,7 +273,7 @@ not_a_sun4:
lda [%o1] ASI_M_BYPASS, %o2 ! This is the 0x0 16MB pgd
/* Calculate to KERNBASE entry. */
- add %o1, KERNBASE >> (SRMMU_PGDIR_SHIFT - 2), %o3
+ add %o1, KERNBASE >> (PGDIR_SHIFT - 2), %o3
/* Poke the entry into the calculated address. */
sta %o2, [%o3] ASI_M_BYPASS
@@ -317,7 +317,7 @@ srmmu_not_viking:
sll %g1, 0x8, %g1 ! make phys addr for l1 tbl
lda [%g1] ASI_M_BYPASS, %g2 ! get level1 entry for 0x0
- add %g1, KERNBASE >> (SRMMU_PGDIR_SHIFT - 2), %g3
+ add %g1, KERNBASE >> (PGDIR_SHIFT - 2), %g3
sta %g2, [%g3] ASI_M_BYPASS ! place at KERNBASE entry
b go_to_highmem
nop ! wheee....
@@ -341,7 +341,7 @@ leon_remap:
sll %g1, 0x8, %g1 ! make phys addr for l1 tbl
lda [%g1] ASI_M_BYPASS, %g2 ! get level1 entry for 0x0
- add %g1, KERNBASE >> (SRMMU_PGDIR_SHIFT - 2), %g3
+ add %g1, KERNBASE >> (PGDIR_SHIFT - 2), %g3
sta %g2, [%g3] ASI_M_BYPASS ! place at KERNBASE entry
b go_to_highmem
nop ! wheee....
diff --git a/arch/sparc/mm/hypersparc.S b/arch/sparc/mm/hypersparc.S
index 66885a8..6c2521e 100644
--- a/arch/sparc/mm/hypersparc.S
+++ b/arch/sparc/mm/hypersparc.S
@@ -10,6 +10,7 @@
#include <asm/asm-offsets.h>
#include <asm/asi.h>
#include <asm/page.h>
+#include <asm/pgtable.h>
#include <asm/pgtsrmmu.h>
#include <linux/init.h>
@@ -293,7 +294,7 @@ hypersparc_flush_tlb_range:
cmp %o3, -1
be hypersparc_flush_tlb_range_out
#endif
- sethi %hi(~((1 << SRMMU_PGDIR_SHIFT) - 1)), %o4
+ sethi %hi(~((1 << PGDIR_SHIFT) - 1)), %o4
sta %o3, [%g1] ASI_M_MMUREGS
and %o1, %o4, %o1
add %o1, 0x200, %o1
diff --git a/arch/sparc/mm/srmmu.c b/arch/sparc/mm/srmmu.c
index cb9ded8..50da4bc 100644
--- a/arch/sparc/mm/srmmu.c
+++ b/arch/sparc/mm/srmmu.c
@@ -136,26 +136,14 @@ static void msi_set_sync(void)
void pmd_set(pmd_t *pmdp, pte_t *ptep)
{
- unsigned long ptp; /* Physical address, shifted right by 4 */
- int i;
-
- ptp = __nocache_pa(ptep) >> 4;
- for (i = 0; i < PTRS_PER_PTE/SRMMU_REAL_PTRS_PER_PTE; i++) {
- set_pte((pte_t *)&pmdp->pmdv[i], __pte(SRMMU_ET_PTD | ptp));
- ptp += (SRMMU_REAL_PTRS_PER_PTE * sizeof(pte_t) >> 4);
- }
+ unsigned long ptp = __nocache_pa(ptep) >> 4;
+ set_pte((pte_t *)&pmd_val(*pmdp), __pte(SRMMU_ET_PTD | ptp));
}
void pmd_populate(struct mm_struct *mm, pmd_t *pmdp, struct page *ptep)
{
- unsigned long ptp; /* Physical address, shifted right by 4 */
- int i;
-
- ptp = page_to_pfn(ptep) << (PAGE_SHIFT-4); /* watch for overflow */
- for (i = 0; i < PTRS_PER_PTE/SRMMU_REAL_PTRS_PER_PTE; i++) {
- set_pte((pte_t *)&pmdp->pmdv[i], __pte(SRMMU_ET_PTD | ptp));
- ptp += (SRMMU_REAL_PTRS_PER_PTE * sizeof(pte_t) >> 4);
- }
+ unsigned long ptp = page_to_pfn(ptep) << (PAGE_SHIFT-4); /* watch for overflow */
+ set_pte((pte_t *)&pmd_val(*pmdp), __pte(SRMMU_ET_PTD | ptp));
}
/* Find an entry in the third-level page table.. */
@@ -163,7 +151,7 @@ pte_t *pte_offset_kernel(pmd_t *dir, unsigned long address)
{
void *pte;
- pte = __nocache_va((dir->pmdv[0] & SRMMU_PTD_PMASK) << 4);
+ pte = __nocache_va((pmd_val(*dir) & SRMMU_PTD_PMASK) << 4);
return (pte_t *) pte +
((address >> PAGE_SHIFT) & (PTRS_PER_PTE - 1));
}
@@ -400,7 +388,7 @@ void pte_free(struct mm_struct *mm, pgtable_t pte)
p = page_to_pfn(pte) << PAGE_SHIFT; /* Physical address */
/* free non cached virtual address*/
- srmmu_free_nocache(__nocache_va(p), PTE_SIZE);
+ srmmu_free_nocache(__nocache_va(p), SRMMU_PTE_TABLE_SIZE);
}
/* context handling - a dynamically sized pool is used */
@@ -822,13 +810,13 @@ static void __init srmmu_inherit_prom_mappings(unsigned long start,
what = 0;
addr = start - PAGE_SIZE;
- if (!(start & ~(SRMMU_REAL_PMD_MASK))) {
- if (srmmu_probe(addr + SRMMU_REAL_PMD_SIZE) == probed)
+ if (!(start & ~(PMD_MASK))) {
+ if (srmmu_probe(addr + PMD_SIZE) == probed)
what = 1;
}
- if (!(start & ~(SRMMU_PGDIR_MASK))) {
- if (srmmu_probe(addr + SRMMU_PGDIR_SIZE) == probed)
+ if (!(start & ~(PGDIR_MASK))) {
+ if (srmmu_probe(addr + PGDIR_SIZE) == probed)
what = 2;
}
@@ -837,7 +825,7 @@ static void __init srmmu_inherit_prom_mappings(unsigned long start,
pudp = pud_offset(p4dp, start);
if (what == 2) {
*(pgd_t *)__nocache_fix(pgdp) = __pgd(probed);
- start += SRMMU_PGDIR_SIZE;
+ start += PGDIR_SIZE;
continue;
}
if (pud_none(*(pud_t *)__nocache_fix(pudp))) {
@@ -849,6 +837,11 @@ static void __init srmmu_inherit_prom_mappings(unsigned long start,
pud_set(__nocache_fix(pudp), pmdp);
}
pmdp = pmd_offset(__nocache_fix(pgdp), start);
+ if (what == 1) {
+ *(pmd_t *)__nocache_fix(pmdp) = __pmd(probed);
+ start += PMD_SIZE;
+ continue;
+ }
if (srmmu_pmd_none(*(pmd_t *)__nocache_fix(pmdp))) {
ptep = __srmmu_get_nocache(PTE_SIZE, PTE_SIZE);
if (ptep == NULL)
@@ -856,19 +849,6 @@ static void __init srmmu_inherit_prom_mappings(unsigned long start,
memset(__nocache_fix(ptep), 0, PTE_SIZE);
pmd_set(__nocache_fix(pmdp), ptep);
}
- if (what == 1) {
- /* We bend the rule where all 16 PTPs in a pmd_t point
- * inside the same PTE page, and we leak a perfectly
- * good hardware PTE piece. Alternatives seem worse.
- */
- unsigned int x; /* Index of HW PMD in soft cluster */
- unsigned long *val;
- x = (start >> PMD_SHIFT) & 15;
- val = &pmdp->pmdv[x];
- *(unsigned long *)__nocache_fix(val) = probed;
- start += SRMMU_REAL_PMD_SIZE;
- continue;
- }
ptep = pte_offset_kernel(__nocache_fix(pmdp), start);
*(pte_t *)__nocache_fix(ptep) = __pte(probed);
start += PAGE_SIZE;
@@ -890,9 +870,9 @@ static void __init do_large_mapping(unsigned long vaddr, unsigned long phys_base
/* Map sp_bank entry SP_ENTRY, starting at virtual address VBASE. */
static unsigned long __init map_spbank(unsigned long vbase, int sp_entry)
{
- unsigned long pstart = (sp_banks[sp_entry].base_addr & SRMMU_PGDIR_MASK);
- unsigned long vstart = (vbase & SRMMU_PGDIR_MASK);
- unsigned long vend = SRMMU_PGDIR_ALIGN(vbase + sp_banks[sp_entry].num_bytes);
+ unsigned long pstart = (sp_banks[sp_entry].base_addr & PGDIR_MASK);
+ unsigned long vstart = (vbase & PGDIR_MASK);
+ unsigned long vend = PGDIR_ALIGN(vbase + sp_banks[sp_entry].num_bytes);
/* Map "low" memory only */
const unsigned long min_vaddr = PAGE_OFFSET;
const unsigned long max_vaddr = PAGE_OFFSET + SRMMU_MAXMEM;
@@ -905,7 +885,7 @@ static unsigned long __init map_spbank(unsigned long vbase, int sp_entry)
while (vstart < vend) {
do_large_mapping(vstart, pstart);
- vstart += SRMMU_PGDIR_SIZE; pstart += SRMMU_PGDIR_SIZE;
+ vstart += PGDIR_SIZE; pstart += PGDIR_SIZE;
}
return vstart;
}
diff --git a/arch/sparc/mm/viking.S b/arch/sparc/mm/viking.S
index adaef6e..48f062d 100644
--- a/arch/sparc/mm/viking.S
+++ b/arch/sparc/mm/viking.S
@@ -13,6 +13,7 @@
#include <asm/asi.h>
#include <asm/mxcc.h>
#include <asm/page.h>
+#include <asm/pgtable.h>
#include <asm/pgtsrmmu.h>
#include <asm/viking.h>
@@ -157,7 +158,7 @@ viking_flush_tlb_range:
cmp %o3, -1
be 2f
#endif
- sethi %hi(~((1 << SRMMU_PGDIR_SHIFT) - 1)), %o4
+ sethi %hi(~((1 << PGDIR_SHIFT) - 1)), %o4
sta %o3, [%g1] ASI_M_MMUREGS
and %o1, %o4, %o1
add %o1, 0x200, %o1
@@ -243,7 +244,7 @@ sun4dsmp_flush_tlb_range:
ld [%o0 + VMA_VM_MM], %o0
ld [%o0 + AOFF_mm_context], %o3
lda [%g1] ASI_M_MMUREGS, %g5
- sethi %hi(~((1 << SRMMU_PGDIR_SHIFT) - 1)), %o4
+ sethi %hi(~((1 << PGDIR_SHIFT) - 1)), %o4
sta %o3, [%g1] ASI_M_MMUREGS
and %o1, %o4, %o1
add %o1, 0x200, %o1