cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
Log | Files | Refs | README | LICENSE | sfeed.txt

pgtable.h (19796B)


      1/* SPDX-License-Identifier: GPL-2.0 */
      2#ifndef _ASM_POWERPC_BOOK3S_32_PGTABLE_H
      3#define _ASM_POWERPC_BOOK3S_32_PGTABLE_H
      4
      5#include <asm-generic/pgtable-nopmd.h>
      6
      7/*
      8 * The "classic" 32-bit implementation of the PowerPC MMU uses a hash
      9 * table containing PTEs, together with a set of 16 segment registers,
     10 * to define the virtual to physical address mapping.
     11 *
     12 * We use the hash table as an extended TLB, i.e. a cache of currently
     13 * active mappings.  We maintain a two-level page table tree, much
     14 * like that used by the i386, for the sake of the Linux memory
     15 * management code.  Low-level assembler code in hash_low_32.S
     16 * (procedure hash_page) is responsible for extracting ptes from the
     17 * tree and putting them into the hash table when necessary, and
     18 * updating the accessed and modified bits in the page table tree.
     19 */
     20
     21#define _PAGE_PRESENT	0x001	/* software: pte contains a translation */
     22#define _PAGE_HASHPTE	0x002	/* hash_page has made an HPTE for this pte */
     23#define _PAGE_USER	0x004	/* usermode access allowed */
     24#define _PAGE_GUARDED	0x008	/* G: prohibit speculative access */
     25#define _PAGE_COHERENT	0x010	/* M: enforce memory coherence (SMP systems) */
     26#define _PAGE_NO_CACHE	0x020	/* I: cache inhibit */
     27#define _PAGE_WRITETHRU	0x040	/* W: cache write-through */
     28#define _PAGE_DIRTY	0x080	/* C: page changed */
     29#define _PAGE_ACCESSED	0x100	/* R: page referenced */
     30#define _PAGE_EXEC	0x200	/* software: exec allowed */
     31#define _PAGE_RW	0x400	/* software: user write access allowed */
     32#define _PAGE_SPECIAL	0x800	/* software: Special page */
     33
     34#ifdef CONFIG_PTE_64BIT
     35/* We never clear the high word of the pte */
     36#define _PTE_NONE_MASK	(0xffffffff00000000ULL | _PAGE_HASHPTE)
     37#else
     38#define _PTE_NONE_MASK	_PAGE_HASHPTE
     39#endif
     40
     41#define _PMD_PRESENT	0
     42#define _PMD_PRESENT_MASK (PAGE_MASK)
     43#define _PMD_BAD	(~PAGE_MASK)
     44
     45/* And here we include common definitions */
     46
     47#define _PAGE_KERNEL_RO		0
     48#define _PAGE_KERNEL_ROX	(_PAGE_EXEC)
     49#define _PAGE_KERNEL_RW		(_PAGE_DIRTY | _PAGE_RW)
     50#define _PAGE_KERNEL_RWX	(_PAGE_DIRTY | _PAGE_RW | _PAGE_EXEC)
     51
     52#define _PAGE_HPTEFLAGS _PAGE_HASHPTE
     53
     54#ifndef __ASSEMBLY__
     55
     56static inline bool pte_user(pte_t pte)
     57{
     58	return pte_val(pte) & _PAGE_USER;
     59}
     60#endif /* __ASSEMBLY__ */
     61
     62/*
     63 * Location of the PFN in the PTE. Most 32-bit platforms use the same
     64 * as _PAGE_SHIFT here (ie, naturally aligned).
     65 * Platform who don't just pre-define the value so we don't override it here.
     66 */
     67#define PTE_RPN_SHIFT	(PAGE_SHIFT)
     68
     69/*
     70 * The mask covered by the RPN must be a ULL on 32-bit platforms with
     71 * 64-bit PTEs.
     72 */
     73#ifdef CONFIG_PTE_64BIT
     74#define PTE_RPN_MASK	(~((1ULL << PTE_RPN_SHIFT) - 1))
     75#define MAX_POSSIBLE_PHYSMEM_BITS 36
     76#else
     77#define PTE_RPN_MASK	(~((1UL << PTE_RPN_SHIFT) - 1))
     78#define MAX_POSSIBLE_PHYSMEM_BITS 32
     79#endif
     80
     81/*
     82 * _PAGE_CHG_MASK masks of bits that are to be preserved across
     83 * pgprot changes.
     84 */
     85#define _PAGE_CHG_MASK	(PTE_RPN_MASK | _PAGE_HASHPTE | _PAGE_DIRTY | \
     86			 _PAGE_ACCESSED | _PAGE_SPECIAL)
     87
     88/*
     89 * We define 2 sets of base prot bits, one for basic pages (ie,
     90 * cacheable kernel and user pages) and one for non cacheable
     91 * pages. We always set _PAGE_COHERENT when SMP is enabled or
     92 * the processor might need it for DMA coherency.
     93 */
     94#define _PAGE_BASE_NC	(_PAGE_PRESENT | _PAGE_ACCESSED)
     95#define _PAGE_BASE	(_PAGE_BASE_NC | _PAGE_COHERENT)
     96
     97/*
     98 * Permission masks used to generate the __P and __S table.
     99 *
    100 * Note:__pgprot is defined in arch/powerpc/include/asm/page.h
    101 *
    102 * Write permissions imply read permissions for now.
    103 */
    104#define PAGE_NONE	__pgprot(_PAGE_BASE)
    105#define PAGE_SHARED	__pgprot(_PAGE_BASE | _PAGE_USER | _PAGE_RW)
    106#define PAGE_SHARED_X	__pgprot(_PAGE_BASE | _PAGE_USER | _PAGE_RW | _PAGE_EXEC)
    107#define PAGE_COPY	__pgprot(_PAGE_BASE | _PAGE_USER)
    108#define PAGE_COPY_X	__pgprot(_PAGE_BASE | _PAGE_USER | _PAGE_EXEC)
    109#define PAGE_READONLY	__pgprot(_PAGE_BASE | _PAGE_USER)
    110#define PAGE_READONLY_X	__pgprot(_PAGE_BASE | _PAGE_USER | _PAGE_EXEC)
    111
    112/* Permission masks used for kernel mappings */
    113#define PAGE_KERNEL	__pgprot(_PAGE_BASE | _PAGE_KERNEL_RW)
    114#define PAGE_KERNEL_NC	__pgprot(_PAGE_BASE_NC | _PAGE_KERNEL_RW | _PAGE_NO_CACHE)
    115#define PAGE_KERNEL_NCG	__pgprot(_PAGE_BASE_NC | _PAGE_KERNEL_RW | \
    116				 _PAGE_NO_CACHE | _PAGE_GUARDED)
    117#define PAGE_KERNEL_X	__pgprot(_PAGE_BASE | _PAGE_KERNEL_RWX)
    118#define PAGE_KERNEL_RO	__pgprot(_PAGE_BASE | _PAGE_KERNEL_RO)
    119#define PAGE_KERNEL_ROX	__pgprot(_PAGE_BASE | _PAGE_KERNEL_ROX)
    120
    121/*
    122 * Protection used for kernel text. We want the debuggers to be able to
    123 * set breakpoints anywhere, so don't write protect the kernel text
    124 * on platforms where such control is possible.
    125 */
    126#if defined(CONFIG_KGDB) || defined(CONFIG_XMON) || defined(CONFIG_BDI_SWITCH) ||\
    127	defined(CONFIG_KPROBES) || defined(CONFIG_DYNAMIC_FTRACE)
    128#define PAGE_KERNEL_TEXT	PAGE_KERNEL_X
    129#else
    130#define PAGE_KERNEL_TEXT	PAGE_KERNEL_ROX
    131#endif
    132
    133/* Make modules code happy. We don't set RO yet */
    134#define PAGE_KERNEL_EXEC	PAGE_KERNEL_X
    135
    136/* Advertise special mapping type for AGP */
    137#define PAGE_AGP		(PAGE_KERNEL_NC)
    138#define HAVE_PAGE_AGP
    139
    140#define PTE_INDEX_SIZE	PTE_SHIFT
    141#define PMD_INDEX_SIZE	0
    142#define PUD_INDEX_SIZE	0
    143#define PGD_INDEX_SIZE	(32 - PGDIR_SHIFT)
    144
    145#define PMD_CACHE_INDEX	PMD_INDEX_SIZE
    146#define PUD_CACHE_INDEX	PUD_INDEX_SIZE
    147
    148#ifndef __ASSEMBLY__
    149#define PTE_TABLE_SIZE	(sizeof(pte_t) << PTE_INDEX_SIZE)
    150#define PMD_TABLE_SIZE	0
    151#define PUD_TABLE_SIZE	0
    152#define PGD_TABLE_SIZE	(sizeof(pgd_t) << PGD_INDEX_SIZE)
    153
    154/* Bits to mask out from a PMD to get to the PTE page */
    155#define PMD_MASKED_BITS		(PTE_TABLE_SIZE - 1)
    156#endif	/* __ASSEMBLY__ */
    157
    158#define PTRS_PER_PTE	(1 << PTE_INDEX_SIZE)
    159#define PTRS_PER_PGD	(1 << PGD_INDEX_SIZE)
    160
    161/*
    162 * The normal case is that PTEs are 32-bits and we have a 1-page
    163 * 1024-entry pgdir pointing to 1-page 1024-entry PTE pages.  -- paulus
    164 *
    165 * For any >32-bit physical address platform, we can use the following
    166 * two level page table layout where the pgdir is 8KB and the MS 13 bits
    167 * are an index to the second level table.  The combined pgdir/pmd first
    168 * level has 2048 entries and the second level has 512 64-bit PTE entries.
    169 * -Matt
    170 */
    171/* PGDIR_SHIFT determines what a top-level page table entry can map */
    172#define PGDIR_SHIFT	(PAGE_SHIFT + PTE_INDEX_SIZE)
    173#define PGDIR_SIZE	(1UL << PGDIR_SHIFT)
    174#define PGDIR_MASK	(~(PGDIR_SIZE-1))
    175
    176#define USER_PTRS_PER_PGD	(TASK_SIZE / PGDIR_SIZE)
    177
    178#ifndef __ASSEMBLY__
    179
    180int map_kernel_page(unsigned long va, phys_addr_t pa, pgprot_t prot);
    181void unmap_kernel_page(unsigned long va);
    182
    183#endif /* !__ASSEMBLY__ */
    184
    185/*
    186 * This is the bottom of the PKMAP area with HIGHMEM or an arbitrary
    187 * value (for now) on others, from where we can start layout kernel
    188 * virtual space that goes below PKMAP and FIXMAP
    189 */
    190#include <asm/fixmap.h>
    191
    192/*
    193 * ioremap_bot starts at that address. Early ioremaps move down from there,
    194 * until mem_init() at which point this becomes the top of the vmalloc
    195 * and ioremap space
    196 */
    197#ifdef CONFIG_HIGHMEM
    198#define IOREMAP_TOP	PKMAP_BASE
    199#else
    200#define IOREMAP_TOP	FIXADDR_START
    201#endif
    202
    203/* PPC32 shares vmalloc area with ioremap */
    204#define IOREMAP_START	VMALLOC_START
    205#define IOREMAP_END	VMALLOC_END
    206
    207/*
    208 * Just any arbitrary offset to the start of the vmalloc VM area: the
    209 * current 16MB value just means that there will be a 64MB "hole" after the
    210 * physical memory until the kernel virtual memory starts.  That means that
    211 * any out-of-bounds memory accesses will hopefully be caught.
    212 * The vmalloc() routines leaves a hole of 4kB between each vmalloced
    213 * area for the same reason. ;)
    214 *
    215 * We no longer map larger than phys RAM with the BATs so we don't have
    216 * to worry about the VMALLOC_OFFSET causing problems.  We do have to worry
    217 * about clashes between our early calls to ioremap() that start growing down
    218 * from ioremap_base being run into the VM area allocations (growing upwards
    219 * from VMALLOC_START).  For this reason we have ioremap_bot to check when
    220 * we actually run into our mappings setup in the early boot with the VM
    221 * system.  This really does become a problem for machines with good amounts
    222 * of RAM.  -- Cort
    223 */
    224#define VMALLOC_OFFSET (0x1000000) /* 16M */
    225
    226#define VMALLOC_START ((((long)high_memory + VMALLOC_OFFSET) & ~(VMALLOC_OFFSET-1)))
    227
    228#ifdef CONFIG_KASAN_VMALLOC
    229#define VMALLOC_END	ALIGN_DOWN(ioremap_bot, PAGE_SIZE << KASAN_SHADOW_SCALE_SHIFT)
    230#else
    231#define VMALLOC_END	ioremap_bot
    232#endif
    233
    234#define MODULES_END	ALIGN_DOWN(PAGE_OFFSET, SZ_256M)
    235#define MODULES_VADDR	(MODULES_END - SZ_256M)
    236
    237#ifndef __ASSEMBLY__
    238#include <linux/sched.h>
    239#include <linux/threads.h>
    240
    241/* Bits to mask out from a PGD to get to the PUD page */
    242#define PGD_MASKED_BITS		0
    243
    244#define pte_ERROR(e) \
    245	pr_err("%s:%d: bad pte %llx.\n", __FILE__, __LINE__, \
    246		(unsigned long long)pte_val(e))
    247#define pgd_ERROR(e) \
    248	pr_err("%s:%d: bad pgd %08lx.\n", __FILE__, __LINE__, pgd_val(e))
    249/*
    250 * Bits in a linux-style PTE.  These match the bits in the
    251 * (hardware-defined) PowerPC PTE as closely as possible.
    252 */
    253
    254#define pte_clear(mm, addr, ptep) \
    255	do { pte_update(mm, addr, ptep, ~_PAGE_HASHPTE, 0, 0); } while (0)
    256
    257#define pmd_none(pmd)		(!pmd_val(pmd))
    258#define	pmd_bad(pmd)		(pmd_val(pmd) & _PMD_BAD)
    259#define	pmd_present(pmd)	(pmd_val(pmd) & _PMD_PRESENT_MASK)
    260static inline void pmd_clear(pmd_t *pmdp)
    261{
    262	*pmdp = __pmd(0);
    263}
    264
    265
    266/*
    267 * When flushing the tlb entry for a page, we also need to flush the hash
    268 * table entry.  flush_hash_pages is assembler (for speed) in hashtable.S.
    269 */
    270extern int flush_hash_pages(unsigned context, unsigned long va,
    271			    unsigned long pmdval, int count);
    272
    273/* Add an HPTE to the hash table */
    274extern void add_hash_page(unsigned context, unsigned long va,
    275			  unsigned long pmdval);
    276
    277/* Flush an entry from the TLB/hash table */
    278static inline void flush_hash_entry(struct mm_struct *mm, pte_t *ptep, unsigned long addr)
    279{
    280	if (mmu_has_feature(MMU_FTR_HPTE_TABLE)) {
    281		unsigned long ptephys = __pa(ptep) & PAGE_MASK;
    282
    283		flush_hash_pages(mm->context.id, addr, ptephys, 1);
    284	}
    285}
    286
    287/*
    288 * PTE updates. This function is called whenever an existing
    289 * valid PTE is updated. This does -not- include set_pte_at()
    290 * which nowadays only sets a new PTE.
    291 *
    292 * Depending on the type of MMU, we may need to use atomic updates
    293 * and the PTE may be either 32 or 64 bit wide. In the later case,
    294 * when using atomic updates, only the low part of the PTE is
    295 * accessed atomically.
    296 */
    297static inline pte_basic_t pte_update(struct mm_struct *mm, unsigned long addr, pte_t *p,
    298				     unsigned long clr, unsigned long set, int huge)
    299{
    300	pte_basic_t old;
    301
    302	if (mmu_has_feature(MMU_FTR_HPTE_TABLE)) {
    303		unsigned long tmp;
    304
    305		asm volatile(
    306#ifndef CONFIG_PTE_64BIT
    307	"1:	lwarx	%0, 0, %3\n"
    308	"	andc	%1, %0, %4\n"
    309#else
    310	"1:	lwarx	%L0, 0, %3\n"
    311	"	lwz	%0, -4(%3)\n"
    312	"	andc	%1, %L0, %4\n"
    313#endif
    314	"	or	%1, %1, %5\n"
    315	"	stwcx.	%1, 0, %3\n"
    316	"	bne-	1b"
    317		: "=&r" (old), "=&r" (tmp), "=m" (*p)
    318#ifndef CONFIG_PTE_64BIT
    319		: "r" (p),
    320#else
    321		: "b" ((unsigned long)(p) + 4),
    322#endif
    323		  "r" (clr), "r" (set), "m" (*p)
    324		: "cc" );
    325	} else {
    326		old = pte_val(*p);
    327
    328		*p = __pte((old & ~(pte_basic_t)clr) | set);
    329	}
    330
    331	return old;
    332}
    333
    334/*
    335 * 2.6 calls this without flushing the TLB entry; this is wrong
    336 * for our hash-based implementation, we fix that up here.
    337 */
    338#define __HAVE_ARCH_PTEP_TEST_AND_CLEAR_YOUNG
    339static inline int __ptep_test_and_clear_young(struct mm_struct *mm,
    340					      unsigned long addr, pte_t *ptep)
    341{
    342	unsigned long old;
    343	old = pte_update(mm, addr, ptep, _PAGE_ACCESSED, 0, 0);
    344	if (old & _PAGE_HASHPTE)
    345		flush_hash_entry(mm, ptep, addr);
    346
    347	return (old & _PAGE_ACCESSED) != 0;
    348}
    349#define ptep_test_and_clear_young(__vma, __addr, __ptep) \
    350	__ptep_test_and_clear_young((__vma)->vm_mm, __addr, __ptep)
    351
    352#define __HAVE_ARCH_PTEP_GET_AND_CLEAR
    353static inline pte_t ptep_get_and_clear(struct mm_struct *mm, unsigned long addr,
    354				       pte_t *ptep)
    355{
    356	return __pte(pte_update(mm, addr, ptep, ~_PAGE_HASHPTE, 0, 0));
    357}
    358
    359#define __HAVE_ARCH_PTEP_SET_WRPROTECT
    360static inline void ptep_set_wrprotect(struct mm_struct *mm, unsigned long addr,
    361				      pte_t *ptep)
    362{
    363	pte_update(mm, addr, ptep, _PAGE_RW, 0, 0);
    364}
    365
    366static inline void __ptep_set_access_flags(struct vm_area_struct *vma,
    367					   pte_t *ptep, pte_t entry,
    368					   unsigned long address,
    369					   int psize)
    370{
    371	unsigned long set = pte_val(entry) &
    372		(_PAGE_DIRTY | _PAGE_ACCESSED | _PAGE_RW | _PAGE_EXEC);
    373
    374	pte_update(vma->vm_mm, address, ptep, 0, set, 0);
    375
    376	flush_tlb_page(vma, address);
    377}
    378
    379#define __HAVE_ARCH_PTE_SAME
    380#define pte_same(A,B)	(((pte_val(A) ^ pte_val(B)) & ~_PAGE_HASHPTE) == 0)
    381
    382#define pmd_pfn(pmd)		(pmd_val(pmd) >> PAGE_SHIFT)
    383#define pmd_page(pmd)		pfn_to_page(pmd_pfn(pmd))
    384
    385/*
    386 * Encode and decode a swap entry.
    387 * Note that the bits we use in a PTE for representing a swap entry
    388 * must not include the _PAGE_PRESENT bit or the _PAGE_HASHPTE bit (if used).
    389 *   -- paulus
    390 */
    391#define __swp_type(entry)		((entry).val & 0x1f)
    392#define __swp_offset(entry)		((entry).val >> 5)
    393#define __swp_entry(type, offset)	((swp_entry_t) { (type) | ((offset) << 5) })
    394#define __pte_to_swp_entry(pte)		((swp_entry_t) { pte_val(pte) >> 3 })
    395#define __swp_entry_to_pte(x)		((pte_t) { (x).val << 3 })
    396
    397/* Generic accessors to PTE bits */
    398static inline int pte_write(pte_t pte)		{ return !!(pte_val(pte) & _PAGE_RW);}
    399static inline int pte_read(pte_t pte)		{ return 1; }
    400static inline int pte_dirty(pte_t pte)		{ return !!(pte_val(pte) & _PAGE_DIRTY); }
    401static inline int pte_young(pte_t pte)		{ return !!(pte_val(pte) & _PAGE_ACCESSED); }
    402static inline int pte_special(pte_t pte)	{ return !!(pte_val(pte) & _PAGE_SPECIAL); }
    403static inline int pte_none(pte_t pte)		{ return (pte_val(pte) & ~_PTE_NONE_MASK) == 0; }
    404static inline bool pte_exec(pte_t pte)		{ return pte_val(pte) & _PAGE_EXEC; }
    405
    406static inline int pte_present(pte_t pte)
    407{
    408	return pte_val(pte) & _PAGE_PRESENT;
    409}
    410
    411static inline bool pte_hw_valid(pte_t pte)
    412{
    413	return pte_val(pte) & _PAGE_PRESENT;
    414}
    415
    416static inline bool pte_hashpte(pte_t pte)
    417{
    418	return !!(pte_val(pte) & _PAGE_HASHPTE);
    419}
    420
    421static inline bool pte_ci(pte_t pte)
    422{
    423	return !!(pte_val(pte) & _PAGE_NO_CACHE);
    424}
    425
    426/*
    427 * We only find page table entry in the last level
    428 * Hence no need for other accessors
    429 */
    430#define pte_access_permitted pte_access_permitted
    431static inline bool pte_access_permitted(pte_t pte, bool write)
    432{
    433	/*
    434	 * A read-only access is controlled by _PAGE_USER bit.
    435	 * We have _PAGE_READ set for WRITE and EXECUTE
    436	 */
    437	if (!pte_present(pte) || !pte_user(pte) || !pte_read(pte))
    438		return false;
    439
    440	if (write && !pte_write(pte))
    441		return false;
    442
    443	return true;
    444}
    445
    446/* Conversion functions: convert a page and protection to a page entry,
    447 * and a page entry and page directory to the page they refer to.
    448 *
    449 * Even if PTEs can be unsigned long long, a PFN is always an unsigned
    450 * long for now.
    451 */
    452static inline pte_t pfn_pte(unsigned long pfn, pgprot_t pgprot)
    453{
    454	return __pte(((pte_basic_t)(pfn) << PTE_RPN_SHIFT) |
    455		     pgprot_val(pgprot));
    456}
    457
    458static inline unsigned long pte_pfn(pte_t pte)
    459{
    460	return pte_val(pte) >> PTE_RPN_SHIFT;
    461}
    462
    463/* Generic modifiers for PTE bits */
    464static inline pte_t pte_wrprotect(pte_t pte)
    465{
    466	return __pte(pte_val(pte) & ~_PAGE_RW);
    467}
    468
    469static inline pte_t pte_exprotect(pte_t pte)
    470{
    471	return __pte(pte_val(pte) & ~_PAGE_EXEC);
    472}
    473
    474static inline pte_t pte_mkclean(pte_t pte)
    475{
    476	return __pte(pte_val(pte) & ~_PAGE_DIRTY);
    477}
    478
    479static inline pte_t pte_mkold(pte_t pte)
    480{
    481	return __pte(pte_val(pte) & ~_PAGE_ACCESSED);
    482}
    483
    484static inline pte_t pte_mkexec(pte_t pte)
    485{
    486	return __pte(pte_val(pte) | _PAGE_EXEC);
    487}
    488
    489static inline pte_t pte_mkpte(pte_t pte)
    490{
    491	return pte;
    492}
    493
    494static inline pte_t pte_mkwrite(pte_t pte)
    495{
    496	return __pte(pte_val(pte) | _PAGE_RW);
    497}
    498
    499static inline pte_t pte_mkdirty(pte_t pte)
    500{
    501	return __pte(pte_val(pte) | _PAGE_DIRTY);
    502}
    503
    504static inline pte_t pte_mkyoung(pte_t pte)
    505{
    506	return __pte(pte_val(pte) | _PAGE_ACCESSED);
    507}
    508
    509static inline pte_t pte_mkspecial(pte_t pte)
    510{
    511	return __pte(pte_val(pte) | _PAGE_SPECIAL);
    512}
    513
    514static inline pte_t pte_mkhuge(pte_t pte)
    515{
    516	return pte;
    517}
    518
    519static inline pte_t pte_mkprivileged(pte_t pte)
    520{
    521	return __pte(pte_val(pte) & ~_PAGE_USER);
    522}
    523
    524static inline pte_t pte_mkuser(pte_t pte)
    525{
    526	return __pte(pte_val(pte) | _PAGE_USER);
    527}
    528
    529static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
    530{
    531	return __pte((pte_val(pte) & _PAGE_CHG_MASK) | pgprot_val(newprot));
    532}
    533
    534
    535
    536/* This low level function performs the actual PTE insertion
    537 * Setting the PTE depends on the MMU type and other factors. It's
    538 * an horrible mess that I'm not going to try to clean up now but
    539 * I'm keeping it in one place rather than spread around
    540 */
    541static inline void __set_pte_at(struct mm_struct *mm, unsigned long addr,
    542				pte_t *ptep, pte_t pte, int percpu)
    543{
    544#if defined(CONFIG_SMP) && !defined(CONFIG_PTE_64BIT)
    545	/* First case is 32-bit Hash MMU in SMP mode with 32-bit PTEs. We use the
    546	 * helper pte_update() which does an atomic update. We need to do that
    547	 * because a concurrent invalidation can clear _PAGE_HASHPTE. If it's a
    548	 * per-CPU PTE such as a kmap_atomic, we do a simple update preserving
    549	 * the hash bits instead (ie, same as the non-SMP case)
    550	 */
    551	if (percpu)
    552		*ptep = __pte((pte_val(*ptep) & _PAGE_HASHPTE)
    553			      | (pte_val(pte) & ~_PAGE_HASHPTE));
    554	else
    555		pte_update(mm, addr, ptep, ~_PAGE_HASHPTE, pte_val(pte), 0);
    556
    557#elif defined(CONFIG_PTE_64BIT)
    558	/* Second case is 32-bit with 64-bit PTE.  In this case, we
    559	 * can just store as long as we do the two halves in the right order
    560	 * with a barrier in between. This is possible because we take care,
    561	 * in the hash code, to pre-invalidate if the PTE was already hashed,
    562	 * which synchronizes us with any concurrent invalidation.
    563	 * In the percpu case, we also fallback to the simple update preserving
    564	 * the hash bits
    565	 */
    566	if (percpu) {
    567		*ptep = __pte((pte_val(*ptep) & _PAGE_HASHPTE)
    568			      | (pte_val(pte) & ~_PAGE_HASHPTE));
    569		return;
    570	}
    571	if (pte_val(*ptep) & _PAGE_HASHPTE)
    572		flush_hash_entry(mm, ptep, addr);
    573	__asm__ __volatile__("\
    574		stw%X0 %2,%0\n\
    575		eieio\n\
    576		stw%X1 %L2,%1"
    577	: "=m" (*ptep), "=m" (*((unsigned char *)ptep+4))
    578	: "r" (pte) : "memory");
    579
    580#else
    581	/* Third case is 32-bit hash table in UP mode, we need to preserve
    582	 * the _PAGE_HASHPTE bit since we may not have invalidated the previous
    583	 * translation in the hash yet (done in a subsequent flush_tlb_xxx())
    584	 * and see we need to keep track that this PTE needs invalidating
    585	 */
    586	*ptep = __pte((pte_val(*ptep) & _PAGE_HASHPTE)
    587		      | (pte_val(pte) & ~_PAGE_HASHPTE));
    588#endif
    589}
    590
    591/*
    592 * Macro to mark a page protection value as "uncacheable".
    593 */
    594
    595#define _PAGE_CACHE_CTL	(_PAGE_COHERENT | _PAGE_GUARDED | _PAGE_NO_CACHE | \
    596			 _PAGE_WRITETHRU)
    597
    598#define pgprot_noncached pgprot_noncached
    599static inline pgprot_t pgprot_noncached(pgprot_t prot)
    600{
    601	return __pgprot((pgprot_val(prot) & ~_PAGE_CACHE_CTL) |
    602			_PAGE_NO_CACHE | _PAGE_GUARDED);
    603}
    604
    605#define pgprot_noncached_wc pgprot_noncached_wc
    606static inline pgprot_t pgprot_noncached_wc(pgprot_t prot)
    607{
    608	return __pgprot((pgprot_val(prot) & ~_PAGE_CACHE_CTL) |
    609			_PAGE_NO_CACHE);
    610}
    611
    612#define pgprot_cached pgprot_cached
    613static inline pgprot_t pgprot_cached(pgprot_t prot)
    614{
    615	return __pgprot((pgprot_val(prot) & ~_PAGE_CACHE_CTL) |
    616			_PAGE_COHERENT);
    617}
    618
    619#define pgprot_cached_wthru pgprot_cached_wthru
    620static inline pgprot_t pgprot_cached_wthru(pgprot_t prot)
    621{
    622	return __pgprot((pgprot_val(prot) & ~_PAGE_CACHE_CTL) |
    623			_PAGE_COHERENT | _PAGE_WRITETHRU);
    624}
    625
    626#define pgprot_cached_noncoherent pgprot_cached_noncoherent
    627static inline pgprot_t pgprot_cached_noncoherent(pgprot_t prot)
    628{
    629	return __pgprot(pgprot_val(prot) & ~_PAGE_CACHE_CTL);
    630}
    631
    632#define pgprot_writecombine pgprot_writecombine
    633static inline pgprot_t pgprot_writecombine(pgprot_t prot)
    634{
    635	return pgprot_noncached_wc(prot);
    636}
    637
    638#endif /* !__ASSEMBLY__ */
    639
    640#endif /*  _ASM_POWERPC_BOOK3S_32_PGTABLE_H */