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authorPalmer Dabbelt <palmer@dabbelt.com>2017-07-10 21:06:09 -0400
committerPalmer Dabbelt <palmer@dabbelt.com>2017-09-26 18:26:47 -0400
commit07037db5d479f90377c998259a4f9a469c404edf (patch)
tree31f69eeb15052afe454c49673b6b398692f451d4
parent6d60b6ee0c9777b92c47f6dc8aad1dd90612e4fa (diff)
RISC-V: Paging and MMU
This patch contains code to manage the RISC-V MMU, including definitions of the page tables and the page walking code. Signed-off-by: Palmer Dabbelt <palmer@dabbelt.com>
Diffstat
-rw-r--r--arch/riscv/include/asm/mmu_context.h69
-rw-r--r--arch/riscv/include/asm/page.h130
-rw-r--r--arch/riscv/include/asm/pgalloc.h124
-rw-r--r--arch/riscv/include/asm/pgtable-32.h25
-rw-r--r--arch/riscv/include/asm/pgtable-64.h84
-rw-r--r--arch/riscv/include/asm/pgtable-bits.h48
-rw-r--r--arch/riscv/include/asm/pgtable.h430
-rw-r--r--arch/riscv/mm/fault.c282
8 files changed, 1192 insertions, 0 deletions
diff --git a/arch/riscv/include/asm/mmu_context.h b/arch/riscv/include/asm/mmu_context.h
new file mode 100644
index 000000000000..de1fc1631fc4
--- /dev/null
+++ b/arch/riscv/include/asm/mmu_context.h
@@ -0,0 +1,69 @@
1/*
2 * Copyright (C) 2012 Regents of the University of California
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public License
6 * as published by the Free Software Foundation, version 2.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11 * GNU General Public License for more details.
12 */
13
14#ifndef _ASM_RISCV_MMU_CONTEXT_H
15#define _ASM_RISCV_MMU_CONTEXT_H
16
17#include <asm-generic/mm_hooks.h>
18
19#include <linux/mm.h>
20#include <linux/sched.h>
21#include <asm/tlbflush.h>
22
23static inline void enter_lazy_tlb(struct mm_struct *mm,
24 struct task_struct *task)
25{
26}
27
28/* Initialize context-related info for a new mm_struct */
29static inline int init_new_context(struct task_struct *task,
30 struct mm_struct *mm)
31{
32 return 0;
33}
34
35static inline void destroy_context(struct mm_struct *mm)
36{
37}
38
39static inline pgd_t *current_pgdir(void)
40{
41 return pfn_to_virt(csr_read(sptbr) & SPTBR_PPN);
42}
43
44static inline void set_pgdir(pgd_t *pgd)
45{
46 csr_write(sptbr, virt_to_pfn(pgd) | SPTBR_MODE);
47}
48
49static inline void switch_mm(struct mm_struct *prev,
50 struct mm_struct *next, struct task_struct *task)
51{
52 if (likely(prev != next)) {
53 set_pgdir(next->pgd);
54 local_flush_tlb_all();
55 }
56}
57
58static inline void activate_mm(struct mm_struct *prev,
59 struct mm_struct *next)
60{
61 switch_mm(prev, next, NULL);
62}
63
64static inline void deactivate_mm(struct task_struct *task,
65 struct mm_struct *mm)
66{
67}
68
69#endif /* _ASM_RISCV_MMU_CONTEXT_H */
diff --git a/arch/riscv/include/asm/page.h b/arch/riscv/include/asm/page.h
new file mode 100644
index 000000000000..06cfbb3aacbb
--- /dev/null
+++ b/arch/riscv/include/asm/page.h
@@ -0,0 +1,130 @@
1/*
2 * Copyright (C) 2009 Chen Liqin <liqin.chen@sunplusct.com>
3 * Copyright (C) 2012 Regents of the University of California
4 * Copyright (C) 2017 SiFive
5 * Copyright (C) 2017 XiaojingZhu <zhuxiaoj@ict.ac.cn>
6 *
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License
9 * as published by the Free Software Foundation, version 2.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
15 */
16
17#ifndef _ASM_RISCV_PAGE_H
18#define _ASM_RISCV_PAGE_H
19
20#include <linux/pfn.h>
21#include <linux/const.h>
22
23#define PAGE_SHIFT (12)
24#define PAGE_SIZE (_AC(1, UL) << PAGE_SHIFT)
25#define PAGE_MASK (~(PAGE_SIZE - 1))
26
27/*
28 * PAGE_OFFSET -- the first address of the first page of memory.
29 * When not using MMU this corresponds to the first free page in
30 * physical memory (aligned on a page boundary).
31 */
32#define PAGE_OFFSET _AC(CONFIG_PAGE_OFFSET, UL)
33
34#define KERN_VIRT_SIZE (-PAGE_OFFSET)
35
36#ifndef __ASSEMBLY__
37
38#define PAGE_UP(addr) (((addr)+((PAGE_SIZE)-1))&(~((PAGE_SIZE)-1)))
39#define PAGE_DOWN(addr) ((addr)&(~((PAGE_SIZE)-1)))
40
41/* align addr on a size boundary - adjust address up/down if needed */
42#define _ALIGN_UP(addr, size) (((addr)+((size)-1))&(~((size)-1)))
43#define _ALIGN_DOWN(addr, size) ((addr)&(~((size)-1)))
44
45/* align addr on a size boundary - adjust address up if needed */
46#define _ALIGN(addr, size) _ALIGN_UP(addr, size)
47
48#define clear_page(pgaddr) memset((pgaddr), 0, PAGE_SIZE)
49#define copy_page(to, from) memcpy((to), (from), PAGE_SIZE)
50
51#define clear_user_page(pgaddr, vaddr, page) memset((pgaddr), 0, PAGE_SIZE)
52#define copy_user_page(vto, vfrom, vaddr, topg) \
53 memcpy((vto), (vfrom), PAGE_SIZE)
54
55/*
56 * Use struct definitions to apply C type checking
57 */
58
59/* Page Global Directory entry */
60typedef struct {
61 unsigned long pgd;
62} pgd_t;
63
64/* Page Table entry */
65typedef struct {
66 unsigned long pte;
67} pte_t;
68
69typedef struct {
70 unsigned long pgprot;
71} pgprot_t;
72
73typedef struct page *pgtable_t;
74
75#define pte_val(x) ((x).pte)
76#define pgd_val(x) ((x).pgd)
77#define pgprot_val(x) ((x).pgprot)
78
79#define __pte(x) ((pte_t) { (x) })
80#define __pgd(x) ((pgd_t) { (x) })
81#define __pgprot(x) ((pgprot_t) { (x) })
82
83#ifdef CONFIG_64BITS
84#define PTE_FMT "%016lx"
85#else
86#define PTE_FMT "%08lx"
87#endif
88
89extern unsigned long va_pa_offset;
90extern unsigned long pfn_base;
91
92extern unsigned long max_low_pfn;
93extern unsigned long min_low_pfn;
94
95#define __pa(x) ((unsigned long)(x) - va_pa_offset)
96#define __va(x) ((void *)((unsigned long) (x) + va_pa_offset))
97
98#define phys_to_pfn(phys) (PFN_DOWN(phys))
99#define pfn_to_phys(pfn) (PFN_PHYS(pfn))
100
101#define virt_to_pfn(vaddr) (phys_to_pfn(__pa(vaddr)))
102#define pfn_to_virt(pfn) (__va(pfn_to_phys(pfn)))
103
104#define virt_to_page(vaddr) (pfn_to_page(virt_to_pfn(vaddr)))
105#define page_to_virt(page) (pfn_to_virt(page_to_pfn(page)))
106
107#define page_to_phys(page) (pfn_to_phys(page_to_pfn(page)))
108#define page_to_bus(page) (page_to_phys(page))
109#define phys_to_page(paddr) (pfn_to_page(phys_to_pfn(paddr)))
110
111#define pfn_valid(pfn) \
112 (((pfn) >= pfn_base) && (((pfn)-pfn_base) < max_mapnr))
113
114#define ARCH_PFN_OFFSET (pfn_base)
115
116#endif /* __ASSEMBLY__ */
117
118#define virt_addr_valid(vaddr) (pfn_valid(virt_to_pfn(vaddr)))
119
120#define VM_DATA_DEFAULT_FLAGS (VM_READ | VM_WRITE | \
121 VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC)
122
123#include <asm-generic/memory_model.h>
124#include <asm-generic/getorder.h>
125
126/* vDSO support */
127/* We do define AT_SYSINFO_EHDR but don't use the gate mechanism */
128#define __HAVE_ARCH_GATE_AREA
129
130#endif /* _ASM_RISCV_PAGE_H */
diff --git a/arch/riscv/include/asm/pgalloc.h b/arch/riscv/include/asm/pgalloc.h
new file mode 100644
index 000000000000..a79ed5faff3a
--- /dev/null
+++ b/arch/riscv/include/asm/pgalloc.h
@@ -0,0 +1,124 @@
1/*
2 * Copyright (C) 2009 Chen Liqin <liqin.chen@sunplusct.com>
3 * Copyright (C) 2012 Regents of the University of California
4 *
5 * This program is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU General Public License
7 * as published by the Free Software Foundation, version 2.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 */
14
15#ifndef _ASM_RISCV_PGALLOC_H
16#define _ASM_RISCV_PGALLOC_H
17
18#include <linux/mm.h>
19#include <asm/tlb.h>
20
21static inline void pmd_populate_kernel(struct mm_struct *mm,
22 pmd_t *pmd, pte_t *pte)
23{
24 unsigned long pfn = virt_to_pfn(pte);
25
26 set_pmd(pmd, __pmd((pfn << _PAGE_PFN_SHIFT) | _PAGE_TABLE));
27}
28
29static inline void pmd_populate(struct mm_struct *mm,
30 pmd_t *pmd, pgtable_t pte)
31{
32 unsigned long pfn = virt_to_pfn(page_address(pte));
33
34 set_pmd(pmd, __pmd((pfn << _PAGE_PFN_SHIFT) | _PAGE_TABLE));
35}
36
37#ifndef __PAGETABLE_PMD_FOLDED
38static inline void pud_populate(struct mm_struct *mm, pud_t *pud, pmd_t *pmd)
39{
40 unsigned long pfn = virt_to_pfn(pmd);
41
42 set_pud(pud, __pud((pfn << _PAGE_PFN_SHIFT) | _PAGE_TABLE));
43}
44#endif /* __PAGETABLE_PMD_FOLDED */
45
46#define pmd_pgtable(pmd) pmd_page(pmd)
47
48static inline pgd_t *pgd_alloc(struct mm_struct *mm)
49{
50 pgd_t *pgd;
51
52 pgd = (pgd_t *)__get_free_page(GFP_KERNEL);
53 if (likely(pgd != NULL)) {
54 memset(pgd, 0, USER_PTRS_PER_PGD * sizeof(pgd_t));
55 /* Copy kernel mappings */
56 memcpy(pgd + USER_PTRS_PER_PGD,
57 init_mm.pgd + USER_PTRS_PER_PGD,
58 (PTRS_PER_PGD - USER_PTRS_PER_PGD) * sizeof(pgd_t));
59 }
60 return pgd;
61}
62
63static inline void pgd_free(struct mm_struct *mm, pgd_t *pgd)
64{
65 free_page((unsigned long)pgd);
66}
67
68#ifndef __PAGETABLE_PMD_FOLDED
69
70static inline pmd_t *pmd_alloc_one(struct mm_struct *mm, unsigned long addr)
71{
72 return (pmd_t *)__get_free_page(
73 GFP_KERNEL | __GFP_RETRY_MAYFAIL | __GFP_ZERO);
74}
75
76static inline void pmd_free(struct mm_struct *mm, pmd_t *pmd)
77{
78 free_page((unsigned long)pmd);
79}
80
81#define __pmd_free_tlb(tlb, pmd, addr) pmd_free((tlb)->mm, pmd)
82
83#endif /* __PAGETABLE_PMD_FOLDED */
84
85static inline pte_t *pte_alloc_one_kernel(struct mm_struct *mm,
86 unsigned long address)
87{
88 return (pte_t *)__get_free_page(
89 GFP_KERNEL | __GFP_RETRY_MAYFAIL | __GFP_ZERO);
90}
91
92static inline struct page *pte_alloc_one(struct mm_struct *mm,
93 unsigned long address)
94{
95 struct page *pte;
96
97 pte = alloc_page(GFP_KERNEL | __GFP_RETRY_MAYFAIL | __GFP_ZERO);
98 if (likely(pte != NULL))
99 pgtable_page_ctor(pte);
100 return pte;
101}
102
103static inline void pte_free_kernel(struct mm_struct *mm, pte_t *pte)
104{
105 free_page((unsigned long)pte);
106}
107
108static inline void pte_free(struct mm_struct *mm, pgtable_t pte)
109{
110 pgtable_page_dtor(pte);
111 __free_page(pte);
112}
113
114#define __pte_free_tlb(tlb, pte, buf) \
115do { \
116 pgtable_page_dtor(pte); \
117 tlb_remove_page((tlb), pte); \
118} while (0)
119
120static inline void check_pgt_cache(void)
121{
122}
123
124#endif /* _ASM_RISCV_PGALLOC_H */
diff --git a/arch/riscv/include/asm/pgtable-32.h b/arch/riscv/include/asm/pgtable-32.h
new file mode 100644
index 000000000000..d61974b74182
--- /dev/null
+++ b/arch/riscv/include/asm/pgtable-32.h
@@ -0,0 +1,25 @@
1/*
2 * Copyright (C) 2012 Regents of the University of California
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public License
6 * as published by the Free Software Foundation, version 2.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11 * GNU General Public License for more details.
12 */
13
14#ifndef _ASM_RISCV_PGTABLE_32_H
15#define _ASM_RISCV_PGTABLE_32_H
16
17#include <asm-generic/pgtable-nopmd.h>
18#include <linux/const.h>
19
20/* Size of region mapped by a page global directory */
21#define PGDIR_SHIFT 22
22#define PGDIR_SIZE (_AC(1, UL) << PGDIR_SHIFT)
23#define PGDIR_MASK (~(PGDIR_SIZE - 1))
24
25#endif /* _ASM_RISCV_PGTABLE_32_H */
diff --git a/arch/riscv/include/asm/pgtable-64.h b/arch/riscv/include/asm/pgtable-64.h
new file mode 100644
index 000000000000..7aa0ea9bd8bb
--- /dev/null
+++ b/arch/riscv/include/asm/pgtable-64.h
@@ -0,0 +1,84 @@
1/*
2 * Copyright (C) 2012 Regents of the University of California
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public License
6 * as published by the Free Software Foundation, version 2.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11 * GNU General Public License for more details.
12 */
13
14#ifndef _ASM_RISCV_PGTABLE_64_H
15#define _ASM_RISCV_PGTABLE_64_H
16
17#include <linux/const.h>
18
19#define PGDIR_SHIFT 30
20/* Size of region mapped by a page global directory */
21#define PGDIR_SIZE (_AC(1, UL) << PGDIR_SHIFT)
22#define PGDIR_MASK (~(PGDIR_SIZE - 1))
23
24#define PMD_SHIFT 21
25/* Size of region mapped by a page middle directory */
26#define PMD_SIZE (_AC(1, UL) << PMD_SHIFT)
27#define PMD_MASK (~(PMD_SIZE - 1))
28
29/* Page Middle Directory entry */
30typedef struct {
31 unsigned long pmd;
32} pmd_t;
33
34#define pmd_val(x) ((x).pmd)
35#define __pmd(x) ((pmd_t) { (x) })
36
37#define PTRS_PER_PMD (PAGE_SIZE / sizeof(pmd_t))
38
39static inline int pud_present(pud_t pud)
40{
41 return (pud_val(pud) & _PAGE_PRESENT);
42}
43
44static inline int pud_none(pud_t pud)
45{
46 return (pud_val(pud) == 0);
47}
48
49static inline int pud_bad(pud_t pud)
50{
51 return !pud_present(pud);
52}
53
54static inline void set_pud(pud_t *pudp, pud_t pud)
55{
56 *pudp = pud;
57}
58
59static inline void pud_clear(pud_t *pudp)
60{
61 set_pud(pudp, __pud(0));
62}
63
64static inline unsigned long pud_page_vaddr(pud_t pud)
65{
66 return (unsigned long)pfn_to_virt(pud_val(pud) >> _PAGE_PFN_SHIFT);
67}
68
69#define pmd_index(addr) (((addr) >> PMD_SHIFT) & (PTRS_PER_PMD - 1))
70
71static inline pmd_t *pmd_offset(pud_t *pud, unsigned long addr)
72{
73 return (pmd_t *)pud_page_vaddr(*pud) + pmd_index(addr);
74}
75
76static inline pmd_t pfn_pmd(unsigned long pfn, pgprot_t prot)
77{
78 return __pmd((pfn << _PAGE_PFN_SHIFT) | pgprot_val(prot));
79}
80
81#define pmd_ERROR(e) \
82 pr_err("%s:%d: bad pmd %016lx.\n", __FILE__, __LINE__, pmd_val(e))
83
84#endif /* _ASM_RISCV_PGTABLE_64_H */
diff --git a/arch/riscv/include/asm/pgtable-bits.h b/arch/riscv/include/asm/pgtable-bits.h
new file mode 100644
index 000000000000..997ddbb1d370
--- /dev/null
+++ b/arch/riscv/include/asm/pgtable-bits.h
@@ -0,0 +1,48 @@
1/*
2 * Copyright (C) 2012 Regents of the University of California
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public License
6 * as published by the Free Software Foundation, version 2.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11 * GNU General Public License for more details.
12 */
13
14#ifndef _ASM_RISCV_PGTABLE_BITS_H
15#define _ASM_RISCV_PGTABLE_BITS_H
16
17/*
18 * PTE format:
19 * | XLEN-1 10 | 9 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0
20 * PFN reserved for SW D A G U X W R V
21 */
22
23#define _PAGE_ACCESSED_OFFSET 6
24
25#define _PAGE_PRESENT (1 << 0)
26#define _PAGE_READ (1 << 1) /* Readable */
27#define _PAGE_WRITE (1 << 2) /* Writable */
28#define _PAGE_EXEC (1 << 3) /* Executable */
29#define _PAGE_USER (1 << 4) /* User */
30#define _PAGE_GLOBAL (1 << 5) /* Global */
31#define _PAGE_ACCESSED (1 << 6) /* Set by hardware on any access */
32#define _PAGE_DIRTY (1 << 7) /* Set by hardware on any write */
33#define _PAGE_SOFT (1 << 8) /* Reserved for software */
34
35#define _PAGE_SPECIAL _PAGE_SOFT
36#define _PAGE_TABLE _PAGE_PRESENT
37
38#define _PAGE_PFN_SHIFT 10
39
40/* Set of bits to preserve across pte_modify() */
41#define _PAGE_CHG_MASK (~(unsigned long)(_PAGE_PRESENT | _PAGE_READ | \
42 _PAGE_WRITE | _PAGE_EXEC | \
43 _PAGE_USER | _PAGE_GLOBAL))
44
45/* Advertise support for _PAGE_SPECIAL */
46#define __HAVE_ARCH_PTE_SPECIAL
47
48#endif /* _ASM_RISCV_PGTABLE_BITS_H */
diff --git a/arch/riscv/include/asm/pgtable.h b/arch/riscv/include/asm/pgtable.h
new file mode 100644
index 000000000000..3399257780b2
--- /dev/null
+++ b/arch/riscv/include/asm/pgtable.h
@@ -0,0 +1,430 @@
1/*
2 * Copyright (C) 2012 Regents of the University of California
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public License
6 * as published by the Free Software Foundation, version 2.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11 * GNU General Public License for more details.
12 */
13
14#ifndef _ASM_RISCV_PGTABLE_H
15#define _ASM_RISCV_PGTABLE_H
16
17#include <linux/mmzone.h>
18
19#include <asm/pgtable-bits.h>
20
21#ifndef __ASSEMBLY__
22
23#ifdef CONFIG_MMU
24
25/* Page Upper Directory not used in RISC-V */
26#include <asm-generic/pgtable-nopud.h>
27#include <asm/page.h>
28#include <asm/tlbflush.h>
29#include <linux/mm_types.h>
30
31#ifdef CONFIG_64BIT
32#include <asm/pgtable-64.h>
33#else
34#include <asm/pgtable-32.h>
35#endif /* CONFIG_64BIT */
36
37/* Number of entries in the page global directory */
38#define PTRS_PER_PGD (PAGE_SIZE / sizeof(pgd_t))
39/* Number of entries in the page table */
40#define PTRS_PER_PTE (PAGE_SIZE / sizeof(pte_t))
41
42/* Number of PGD entries that a user-mode program can use */
43#define USER_PTRS_PER_PGD (TASK_SIZE / PGDIR_SIZE)
44#define FIRST_USER_ADDRESS 0
45
46/* Page protection bits */
47#define _PAGE_BASE (_PAGE_PRESENT | _PAGE_ACCESSED | _PAGE_USER)
48
49#define PAGE_NONE __pgprot(0)
50#define PAGE_READ __pgprot(_PAGE_BASE | _PAGE_READ)
51#define PAGE_WRITE __pgprot(_PAGE_BASE | _PAGE_READ | _PAGE_WRITE)
52#define PAGE_EXEC __pgprot(_PAGE_BASE | _PAGE_EXEC)
53#define PAGE_READ_EXEC __pgprot(_PAGE_BASE | _PAGE_READ | _PAGE_EXEC)
54#define PAGE_WRITE_EXEC __pgprot(_PAGE_BASE | _PAGE_READ | \
55 _PAGE_EXEC | _PAGE_WRITE)
56
57#define PAGE_COPY PAGE_READ
58#define PAGE_COPY_EXEC PAGE_EXEC
59#define PAGE_COPY_READ_EXEC PAGE_READ_EXEC
60#define PAGE_SHARED PAGE_WRITE
61#define PAGE_SHARED_EXEC PAGE_WRITE_EXEC
62
63#define _PAGE_KERNEL (_PAGE_READ \
64 | _PAGE_WRITE \
65 | _PAGE_PRESENT \
66 | _PAGE_ACCESSED \
67 | _PAGE_DIRTY)
68
69#define PAGE_KERNEL __pgprot(_PAGE_KERNEL)
70#define PAGE_KERNEL_EXEC __pgprot(_PAGE_KERNEL | _PAGE_EXEC)
71
72extern pgd_t swapper_pg_dir[];
73
74/* MAP_PRIVATE permissions: xwr (copy-on-write) */
75#define __P000 PAGE_NONE
76#define __P001 PAGE_READ
77#define __P010 PAGE_COPY
78#define __P011 PAGE_COPY
79#define __P100 PAGE_EXEC
80#define __P101 PAGE_READ_EXEC
81#define __P110 PAGE_COPY_EXEC
82#define __P111 PAGE_COPY_READ_EXEC
83
84/* MAP_SHARED permissions: xwr */
85#define __S000 PAGE_NONE
86#define __S001 PAGE_READ
87#define __S010 PAGE_SHARED
88#define __S011 PAGE_SHARED
89#define __S100 PAGE_EXEC
90#define __S101 PAGE_READ_EXEC
91#define __S110 PAGE_SHARED_EXEC
92#define __S111 PAGE_SHARED_EXEC
93
94/*
95 * ZERO_PAGE is a global shared page that is always zero,
96 * used for zero-mapped memory areas, etc.
97 */
98extern unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)];
99#define ZERO_PAGE(vaddr) (virt_to_page(empty_zero_page))
100
101static inline int pmd_present(pmd_t pmd)
102{
103 return (pmd_val(pmd) & _PAGE_PRESENT);
104}
105
106static inline int pmd_none(pmd_t pmd)
107{
108 return (pmd_val(pmd) == 0);
109}
110
111static inline int pmd_bad(pmd_t pmd)
112{
113 return !pmd_present(pmd);
114}
115
116static inline void set_pmd(pmd_t *pmdp, pmd_t pmd)
117{
118 *pmdp = pmd;
119}
120
121static inline void pmd_clear(pmd_t *pmdp)
122{
123 set_pmd(pmdp, __pmd(0));
124}
125
126
127static inline pgd_t pfn_pgd(unsigned long pfn, pgprot_t prot)
128{
129 return __pgd((pfn << _PAGE_PFN_SHIFT) | pgprot_val(prot));
130}
131
132#define pgd_index(addr) (((addr) >> PGDIR_SHIFT) & (PTRS_PER_PGD - 1))
133
134/* Locate an entry in the page global directory */
135static inline pgd_t *pgd_offset(const struct mm_struct *mm, unsigned long addr)
136{
137 return mm->pgd + pgd_index(addr);
138}
139/* Locate an entry in the kernel page global directory */
140#define pgd_offset_k(addr) pgd_offset(&init_mm, (addr))
141
142static inline struct page *pmd_page(pmd_t pmd)
143{
144 return pfn_to_page(pmd_val(pmd) >> _PAGE_PFN_SHIFT);
145}
146
147static inline unsigned long pmd_page_vaddr(pmd_t pmd)
148{
149 return (unsigned long)pfn_to_virt(pmd_val(pmd) >> _PAGE_PFN_SHIFT);
150}
151
152/* Yields the page frame number (PFN) of a page table entry */
153static inline unsigned long pte_pfn(pte_t pte)
154{
155 return (pte_val(pte) >> _PAGE_PFN_SHIFT);
156}
157
158#define pte_page(x) pfn_to_page(pte_pfn(x))
159
160/* Constructs a page table entry */
161static inline pte_t pfn_pte(unsigned long pfn, pgprot_t prot)
162{
163 return __pte((pfn << _PAGE_PFN_SHIFT) | pgprot_val(prot));
164}
165
166static inline pte_t mk_pte(struct page *page, pgprot_t prot)
167{
168 return pfn_pte(page_to_pfn(page), prot);
169}
170
171#define pte_index(addr) (((addr) >> PAGE_SHIFT) & (PTRS_PER_PTE - 1))
172
173static inline pte_t *pte_offset_kernel(pmd_t *pmd, unsigned long addr)
174{
175 return (pte_t *)pmd_page_vaddr(*pmd) + pte_index(addr);
176}
177
178#define pte_offset_map(dir, addr) pte_offset_kernel((dir), (addr))
179#define pte_unmap(pte) ((void)(pte))
180
181/*
182 * Certain architectures need to do special things when PTEs within
183 * a page table are directly modified. Thus, the following hook is
184 * made available.
185 */
186static inline void set_pte(pte_t *ptep, pte_t pteval)
187{
188 *ptep = pteval;
189}
190
191static inline void set_pte_at(struct mm_struct *mm,
192 unsigned long addr, pte_t *ptep, pte_t pteval)
193{
194 set_pte(ptep, pteval);
195}
196
197static inline void pte_clear(struct mm_struct *mm,
198 unsigned long addr, pte_t *ptep)
199{
200 set_pte_at(mm, addr, ptep, __pte(0));
201}
202
203static inline int pte_present(pte_t pte)
204{
205 return (pte_val(pte) & _PAGE_PRESENT);
206}
207
208static inline int pte_none(pte_t pte)
209{
210 return (pte_val(pte) == 0);
211}
212
213/* static inline int pte_read(pte_t pte) */
214
215static inline int pte_write(pte_t pte)
216{
217 return pte_val(pte) & _PAGE_WRITE;
218}
219
220static inline int pte_huge(pte_t pte)
221{
222 return pte_present(pte)
223 && (pte_val(pte) & (_PAGE_READ | _PAGE_WRITE | _PAGE_EXEC));
224}
225
226/* static inline int pte_exec(pte_t pte) */
227
228static inline int pte_dirty(pte_t pte)
229{
230 return pte_val(pte) & _PAGE_DIRTY;
231}
232
233static inline int pte_young(pte_t pte)
234{
235 return pte_val(pte) & _PAGE_ACCESSED;
236}
237
238static inline int pte_special(pte_t pte)
239{
240 return pte_val(pte) & _PAGE_SPECIAL;
241}
242
243/* static inline pte_t pte_rdprotect(pte_t pte) */
244
245static inline pte_t pte_wrprotect(pte_t pte)
246{
247 return __pte(pte_val(pte) & ~(_PAGE_WRITE));
248}
249
250/* static inline pte_t pte_mkread(pte_t pte) */
251
252static inline pte_t pte_mkwrite(pte_t pte)
253{
254 return __pte(pte_val(pte) | _PAGE_WRITE);
255}
256
257/* static inline pte_t pte_mkexec(pte_t pte) */
258
259static inline pte_t pte_mkdirty(pte_t pte)
260{
261 return __pte(pte_val(pte) | _PAGE_DIRTY);
262}
263
264static inline pte_t pte_mkclean(pte_t pte)
265{
266 return __pte(pte_val(pte) & ~(_PAGE_DIRTY));
267}
268
269static inline pte_t pte_mkyoung(pte_t pte)
270{
271 return __pte(pte_val(pte) | _PAGE_ACCESSED);
272}
273
274static inline pte_t pte_mkold(pte_t pte)
275{
276 return __pte(pte_val(pte) & ~(_PAGE_ACCESSED));
277}
278
279static inline pte_t pte_mkspecial(pte_t pte)
280{
281 return __pte(pte_val(pte) | _PAGE_SPECIAL);
282}
283
284/* Modify page protection bits */
285static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
286{
287 return __pte((pte_val(pte) & _PAGE_CHG_MASK) | pgprot_val(newprot));
288}
289
290#define pgd_ERROR(e) \
291 pr_err("%s:%d: bad pgd " PTE_FMT ".\n", __FILE__, __LINE__, pgd_val(e))
292
293
294/* Commit new configuration to MMU hardware */
295static inline void update_mmu_cache(struct vm_area_struct *vma,
296 unsigned long address, pte_t *ptep)
297{
298 /*
299 * The kernel assumes that TLBs don't cache invalid entries, but
300 * in RISC-V, SFENCE.VMA specifies an ordering constraint, not a
301 * cache flush; it is necessary even after writing invalid entries.
302 * Relying on flush_tlb_fix_spurious_fault would suffice, but
303 * the extra traps reduce performance. So, eagerly SFENCE.VMA.
304 */
305 local_flush_tlb_page(address);
306}
307
308#define __HAVE_ARCH_PTE_SAME
309static inline int pte_same(pte_t pte_a, pte_t pte_b)
310{
311 return pte_val(pte_a) == pte_val(pte_b);
312}
313
314#define __HAVE_ARCH_PTEP_SET_ACCESS_FLAGS
315static inline int ptep_set_access_flags(struct vm_area_struct *vma,
316 unsigned long address, pte_t *ptep,
317 pte_t entry, int dirty)
318{
319 if (!pte_same(*ptep, entry))
320 set_pte_at(vma->vm_mm, address, ptep, entry);
321 /*
322 * update_mmu_cache will unconditionally execute, handling both
323 * the case that the PTE changed and the spurious fault case.
324 */
325 return true;
326}
327
328#define __HAVE_ARCH_PTEP_GET_AND_CLEAR
329static inline pte_t ptep_get_and_clear(struct mm_struct *mm,
330 unsigned long address, pte_t *ptep)
331{
332 return __pte(atomic_long_xchg((atomic_long_t *)ptep, 0));
333}
334
335#define __HAVE_ARCH_PTEP_TEST_AND_CLEAR_YOUNG
336static inline int ptep_test_and_clear_young(struct vm_area_struct *vma,
337 unsigned long address,
338 pte_t *ptep)
339{
340 if (!pte_young(*ptep))
341 return 0;
342 return test_and_clear_bit(_PAGE_ACCESSED_OFFSET, &pte_val(*ptep));
343}
344
345#define __HAVE_ARCH_PTEP_SET_WRPROTECT
346static inline void ptep_set_wrprotect(struct mm_struct *mm,
347 unsigned long address, pte_t *ptep)
348{
349 atomic_long_and(~(unsigned long)_PAGE_WRITE, (atomic_long_t *)ptep);
350}
351
352#define __HAVE_ARCH_PTEP_CLEAR_YOUNG_FLUSH
353static inline int ptep_clear_flush_young(struct vm_area_struct *vma,
354 unsigned long address, pte_t *ptep)
355{
356 /*
357 * This comment is borrowed from x86, but applies equally to RISC-V:
358 *
359 * Clearing the accessed bit without a TLB flush
360 * doesn't cause data corruption. [ It could cause incorrect
361 * page aging and the (mistaken) reclaim of hot pages, but the
362 * chance of that should be relatively low. ]
363 *
364 * So as a performance optimization don't flush the TLB when
365 * clearing the accessed bit, it will eventually be flushed by
366 * a context switch or a VM operation anyway. [ In the rare
367 * event of it not getting flushed for a long time the delay
368 * shouldn't really matter because there's no real memory
369 * pressure for swapout to react to. ]
370 */
371 return ptep_test_and_clear_young(vma, address, ptep);
372}
373
374/*
375 * Encode and decode a swap entry
376 *
377 * Format of swap PTE:
378 * bit 0: _PAGE_PRESENT (zero)
379 * bit 1: reserved for future use (zero)
380 * bits 2 to 6: swap type
381 * bits 7 to XLEN-1: swap offset
382 */
383#define __SWP_TYPE_SHIFT 2
384#define __SWP_TYPE_BITS 5
385#define __SWP_TYPE_MASK ((1UL << __SWP_TYPE_BITS) - 1)
386#define __SWP_OFFSET_SHIFT (__SWP_TYPE_BITS + __SWP_TYPE_SHIFT)
387
388#define MAX_SWAPFILES_CHECK() \
389 BUILD_BUG_ON(MAX_SWAPFILES_SHIFT > __SWP_TYPE_BITS)
390
391#define __swp_type(x) (((x).val >> __SWP_TYPE_SHIFT) & __SWP_TYPE_MASK)
392#define __swp_offset(x) ((x).val >> __SWP_OFFSET_SHIFT)
393#define __swp_entry(type, offset) ((swp_entry_t) \
394 { ((type) << __SWP_TYPE_SHIFT) | ((offset) << __SWP_OFFSET_SHIFT) })
395
396#define __pte_to_swp_entry(pte) ((swp_entry_t) { pte_val(pte) })
397#define __swp_entry_to_pte(x) ((pte_t) { (x).val })
398
399#ifdef CONFIG_FLATMEM
400#define kern_addr_valid(addr) (1) /* FIXME */
401#endif
402
403extern void paging_init(void);
404
405static inline void pgtable_cache_init(void)
406{
407 /* No page table caches to initialize */
408}
409
410#endif /* CONFIG_MMU */
411
412#define VMALLOC_SIZE (KERN_VIRT_SIZE >> 1)
413#define VMALLOC_END (PAGE_OFFSET - 1)
414#define VMALLOC_START (PAGE_OFFSET - VMALLOC_SIZE)
415
416/*
417 * Task size is 0x40000000000 for RV64 or 0xb800000 for RV32.
418 * Note that PGDIR_SIZE must evenly divide TASK_SIZE.
419 */
420#ifdef CONFIG_64BIT
421#define TASK_SIZE (PGDIR_SIZE * PTRS_PER_PGD / 2)
422#else
423#define TASK_SIZE VMALLOC_START
424#endif
425
426#include <asm-generic/pgtable.h>
427
428#endif /* !__ASSEMBLY__ */
429
430#endif /* _ASM_RISCV_PGTABLE_H */
diff --git a/arch/riscv/mm/fault.c b/arch/riscv/mm/fault.c
new file mode 100644
index 000000000000..df2ca3c65048
--- /dev/null
+++ b/arch/riscv/mm/fault.c
@@ -0,0 +1,282 @@
1/*
2 * Copyright (C) 2009 Sunplus Core Technology Co., Ltd.
3 * Lennox Wu <lennox.wu@sunplusct.com>
4 * Chen Liqin <liqin.chen@sunplusct.com>
5 * Copyright (C) 2012 Regents of the University of California
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 2 of the License, or
10 * (at your option) any later version.
11 *
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
16 *
17 * You should have received a copy of the GNU General Public License
18 * along with this program; if not, see the file COPYING, or write
19 * to the Free Software Foundation, Inc.,
20 */
21
22
23#include <linux/mm.h>
24#include <linux/kernel.h>
25#include <linux/interrupt.h>
26#include <linux/perf_event.h>
27#include <linux/signal.h>
28#include <linux/uaccess.h>
29
30#include <asm/pgalloc.h>
31#include <asm/ptrace.h>
32#include <asm/uaccess.h>
33
34/*
35 * This routine handles page faults. It determines the address and the
36 * problem, and then passes it off to one of the appropriate routines.
37 */
38asmlinkage void do_page_fault(struct pt_regs *regs)
39{
40 struct task_struct *tsk;
41 struct vm_area_struct *vma;
42 struct mm_struct *mm;
43 unsigned long addr, cause;
44 unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE;
45 int fault, code = SEGV_MAPERR;
46
47 cause = regs->scause;
48 addr = regs->sbadaddr;
49
50 tsk = current;
51 mm = tsk->mm;
52
53 /*
54 * Fault-in kernel-space virtual memory on-demand.
55 * The 'reference' page table is init_mm.pgd.
56 *
57 * NOTE! We MUST NOT take any locks for this case. We may
58 * be in an interrupt or a critical region, and should
59 * only copy the information from the master page table,
60 * nothing more.
61 */
62 if (unlikely((addr >= VMALLOC_START) && (addr <= VMALLOC_END)))
63 goto vmalloc_fault;
64
65 /* Enable interrupts if they were enabled in the parent context. */
66 if (likely(regs->sstatus & SR_PIE))
67 local_irq_enable();
68
69 /*
70 * If we're in an interrupt, have no user context, or are running
71 * in an atomic region, then we must not take the fault.
72 */
73 if (unlikely(faulthandler_disabled() || !mm))
74 goto no_context;
75
76 if (user_mode(regs))
77 flags |= FAULT_FLAG_USER;
78
79 perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, addr);
80
81retry:
82 down_read(&mm->mmap_sem);
83 vma = find_vma(mm, addr);
84 if (unlikely(!vma))
85 goto bad_area;
86 if (likely(vma->vm_start <= addr))
87 goto good_area;
88 if (unlikely(!(vma->vm_flags & VM_GROWSDOWN)))
89 goto bad_area;
90 if (unlikely(expand_stack(vma, addr)))
91 goto bad_area;
92
93 /*
94 * Ok, we have a good vm_area for this memory access, so
95 * we can handle it.
96 */
97good_area:
98 code = SEGV_ACCERR;
99
100 switch (cause) {
101 case EXC_INST_PAGE_FAULT:
102 if (!(vma->vm_flags & VM_EXEC))
103 goto bad_area;
104 break;
105 case EXC_LOAD_PAGE_FAULT:
106 if (!(vma->vm_flags & VM_READ))
107 goto bad_area;
108 break;
109 case EXC_STORE_PAGE_FAULT:
110 if (!(vma->vm_flags & VM_WRITE))
111 goto bad_area;
112 flags |= FAULT_FLAG_WRITE;
113 break;
114 default:
115 panic("%s: unhandled cause %lu", __func__, cause);
116 }
117
118 /*
119 * If for any reason at all we could not handle the fault,
120 * make sure we exit gracefully rather than endlessly redo
121 * the fault.
122 */
123 fault = handle_mm_fault(vma, addr, flags);
124
125 /*
126 * If we need to retry but a fatal signal is pending, handle the
127 * signal first. We do not need to release the mmap_sem because it
128 * would already be released in __lock_page_or_retry in mm/filemap.c.
129 */
130 if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(tsk))
131 return;
132
133 if (unlikely(fault & VM_FAULT_ERROR)) {
134 if (fault & VM_FAULT_OOM)
135 goto out_of_memory;
136 else if (fault & VM_FAULT_SIGBUS)
137 goto do_sigbus;
138 BUG();
139 }
140
141 /*
142 * Major/minor page fault accounting is only done on the
143 * initial attempt. If we go through a retry, it is extremely
144 * likely that the page will be found in page cache at that point.
145 */
146 if (flags & FAULT_FLAG_ALLOW_RETRY) {
147 if (fault & VM_FAULT_MAJOR) {
148 tsk->maj_flt++;
149 perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ,
150 1, regs, addr);
151 } else {
152 tsk->min_flt++;
153 perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN,
154 1, regs, addr);
155 }
156 if (fault & VM_FAULT_RETRY) {
157 /*
158 * Clear FAULT_FLAG_ALLOW_RETRY to avoid any risk
159 * of starvation.
160 */
161 flags &= ~(FAULT_FLAG_ALLOW_RETRY);
162 flags |= FAULT_FLAG_TRIED;
163
164 /*
165 * No need to up_read(&mm->mmap_sem) as we would
166 * have already released it in __lock_page_or_retry
167 * in mm/filemap.c.
168 */
169 goto retry;
170 }
171 }
172
173 up_read(&mm->mmap_sem);
174 return;
175
176 /*
177 * Something tried to access memory that isn't in our memory map.
178 * Fix it, but check if it's kernel or user first.
179 */
180bad_area:
181 up_read(&mm->mmap_sem);
182 /* User mode accesses just cause a SIGSEGV */
183 if (user_mode(regs)) {
184 do_trap(regs, SIGSEGV, code, addr, tsk);
185 return;
186 }
187
188no_context:
189 /* Are we prepared to handle this kernel fault? */
190 if (fixup_exception(regs))
191 return;
192
193 /*
194 * Oops. The kernel tried to access some bad page. We'll have to
195 * terminate things with extreme prejudice.
196 */
197 bust_spinlocks(1);
198 pr_alert("Unable to handle kernel %s at virtual address " REG_FMT "\n",
199 (addr < PAGE_SIZE) ? "NULL pointer dereference" :
200 "paging request", addr);
201 die(regs, "Oops");
202 do_exit(SIGKILL);
203
204 /*
205 * We ran out of memory, call the OOM killer, and return the userspace
206 * (which will retry the fault, or kill us if we got oom-killed).
207 */
208out_of_memory:
209 up_read(&mm->mmap_sem);
210 if (!user_mode(regs))
211 goto no_context;
212 pagefault_out_of_memory();
213 return;
214
215do_sigbus:
216 up_read(&mm->mmap_sem);
217 /* Kernel mode? Handle exceptions or die */
218 if (!user_mode(regs))
219 goto no_context;
220 do_trap(regs, SIGBUS, BUS_ADRERR, addr, tsk);
221 return;
222
223vmalloc_fault:
224 {
225 pgd_t *pgd, *pgd_k;
226 pud_t *pud, *pud_k;
227 p4d_t *p4d, *p4d_k;
228 pmd_t *pmd, *pmd_k;
229 pte_t *pte_k;
230 int index;
231
232 if (user_mode(regs))
233 goto bad_area;
234
235 /*
236 * Synchronize this task's top level page-table
237 * with the 'reference' page table.
238 *
239 * Do _not_ use "tsk->active_mm->pgd" here.
240 * We might be inside an interrupt in the middle
241 * of a task switch.
242 */
243 index = pgd_index(addr);
244 pgd = (pgd_t *)pfn_to_virt(csr_read(sptbr)) + index;
245 pgd_k = init_mm.pgd + index;
246
247 if (!pgd_present(*pgd_k))
248 goto no_context;
249 set_pgd(pgd, *pgd_k);
250
251 p4d = p4d_offset(pgd, addr);
252 p4d_k = p4d_offset(pgd_k, addr);
253 if (!p4d_present(*p4d_k))
254 goto no_context;
255
256 pud = pud_offset(p4d, addr);
257 pud_k = pud_offset(p4d_k, addr);
258 if (!pud_present(*pud_k))
259 goto no_context;
260
261 /*
262 * Since the vmalloc area is global, it is unnecessary
263 * to copy individual PTEs
264 */
265 pmd = pmd_offset(pud, addr);
266 pmd_k = pmd_offset(pud_k, addr);
267 if (!pmd_present(*pmd_k))
268 goto no_context;
269 set_pmd(pmd, *pmd_k);
270
271 /*
272 * Make sure the actual PTE exists as well to
273 * catch kernel vmalloc-area accesses to non-mapped
274 * addresses. If we don't do this, this will just
275 * silently loop forever.
276 */
277 pte_k = pte_offset_kernel(pmd_k, addr);
278 if (!pte_present(*pte_k))
279 goto no_context;
280 return;
281 }
282}
generated by cgit v1.2.2 (git 2.25.0) at 2025-08-17 14:18:13 -0400