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linux-zen-server/arch/x86/mm/pat/set_memory.c

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Initial commit
2023-08-30 17:53:23 +02:00
// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright 2002 Andi Kleen, SuSE Labs.
* Thanks to Ben LaHaise for precious feedback.
*/
#include <linux/highmem.h>
#include <linux/memblock.h>
#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/interrupt.h>
#include <linux/seq_file.h>
#include <linux/debugfs.h>
#include <linux/pfn.h>
#include <linux/percpu.h>
#include <linux/gfp.h>
#include <linux/pci.h>
#include <linux/vmalloc.h>
#include <linux/libnvdimm.h>
#include <linux/vmstat.h>
#include <linux/kernel.h>
#include <linux/cc_platform.h>
#include <linux/set_memory.h>
#include <linux/memregion.h>
#include <asm/e820/api.h>
#include <asm/processor.h>
#include <asm/tlbflush.h>
#include <asm/sections.h>
#include <asm/setup.h>
#include <linux/uaccess.h>
#include <asm/pgalloc.h>
#include <asm/proto.h>
#include <asm/memtype.h>
#include <asm/hyperv-tlfs.h>
#include <asm/mshyperv.h>
#include "../mm_internal.h"
/*
* The current flushing context - we pass it instead of 5 arguments:
*/
struct cpa_data {
unsigned long *vaddr;
pgd_t *pgd;
pgprot_t mask_set;
pgprot_t mask_clr;
unsigned long numpages;
unsigned long curpage;
unsigned long pfn;
unsigned int flags;
unsigned int force_split : 1,
force_static_prot : 1,
force_flush_all : 1;
struct page **pages;
};
enum cpa_warn {
CPA_CONFLICT,
CPA_PROTECT,
CPA_DETECT,
};
static const int cpa_warn_level = CPA_PROTECT;
/*
* Serialize cpa() (for !DEBUG_PAGEALLOC which uses large identity mappings)
* using cpa_lock. So that we don't allow any other cpu, with stale large tlb
* entries change the page attribute in parallel to some other cpu
* splitting a large page entry along with changing the attribute.
*/
static DEFINE_SPINLOCK(cpa_lock);
#define CPA_FLUSHTLB 1
#define CPA_ARRAY 2
#define CPA_PAGES_ARRAY 4
#define CPA_NO_CHECK_ALIAS 8 /* Do not search for aliases */
static inline pgprot_t cachemode2pgprot(enum page_cache_mode pcm)
{
return __pgprot(cachemode2protval(pcm));
}
#ifdef CONFIG_PROC_FS
static unsigned long direct_pages_count[PG_LEVEL_NUM];
void update_page_count(int level, unsigned long pages)
{
/* Protect against CPA */
spin_lock(&pgd_lock);
direct_pages_count[level] += pages;
spin_unlock(&pgd_lock);
}
static void split_page_count(int level)
{
if (direct_pages_count[level] == 0)
return;
direct_pages_count[level]--;
if (system_state == SYSTEM_RUNNING) {
if (level == PG_LEVEL_2M)
count_vm_event(DIRECT_MAP_LEVEL2_SPLIT);
else if (level == PG_LEVEL_1G)
count_vm_event(DIRECT_MAP_LEVEL3_SPLIT);
}
direct_pages_count[level - 1] += PTRS_PER_PTE;
}
void arch_report_meminfo(struct seq_file *m)
{
seq_printf(m, "DirectMap4k: %8lu kB\n",
direct_pages_count[PG_LEVEL_4K] << 2);
#if defined(CONFIG_X86_64) || defined(CONFIG_X86_PAE)
seq_printf(m, "DirectMap2M: %8lu kB\n",
direct_pages_count[PG_LEVEL_2M] << 11);
#else
seq_printf(m, "DirectMap4M: %8lu kB\n",
direct_pages_count[PG_LEVEL_2M] << 12);
#endif
if (direct_gbpages)
seq_printf(m, "DirectMap1G: %8lu kB\n",
direct_pages_count[PG_LEVEL_1G] << 20);
}
#else
static inline void split_page_count(int level) { }
#endif
#ifdef CONFIG_X86_CPA_STATISTICS
static unsigned long cpa_1g_checked;
static unsigned long cpa_1g_sameprot;
static unsigned long cpa_1g_preserved;
static unsigned long cpa_2m_checked;
static unsigned long cpa_2m_sameprot;
static unsigned long cpa_2m_preserved;
static unsigned long cpa_4k_install;
static inline void cpa_inc_1g_checked(void)
{
cpa_1g_checked++;
}
static inline void cpa_inc_2m_checked(void)
{
cpa_2m_checked++;
}
static inline void cpa_inc_4k_install(void)
{
data_race(cpa_4k_install++);
}
static inline void cpa_inc_lp_sameprot(int level)
{
if (level == PG_LEVEL_1G)
cpa_1g_sameprot++;
else
cpa_2m_sameprot++;
}
static inline void cpa_inc_lp_preserved(int level)
{
if (level == PG_LEVEL_1G)
cpa_1g_preserved++;
else
cpa_2m_preserved++;
}
static int cpastats_show(struct seq_file *m, void *p)
{
seq_printf(m, "1G pages checked: %16lu\n", cpa_1g_checked);
seq_printf(m, "1G pages sameprot: %16lu\n", cpa_1g_sameprot);
seq_printf(m, "1G pages preserved: %16lu\n", cpa_1g_preserved);
seq_printf(m, "2M pages checked: %16lu\n", cpa_2m_checked);
seq_printf(m, "2M pages sameprot: %16lu\n", cpa_2m_sameprot);
seq_printf(m, "2M pages preserved: %16lu\n", cpa_2m_preserved);
seq_printf(m, "4K pages set-checked: %16lu\n", cpa_4k_install);
return 0;
}
static int cpastats_open(struct inode *inode, struct file *file)
{
return single_open(file, cpastats_show, NULL);
}
static const struct file_operations cpastats_fops = {
.open = cpastats_open,
.read = seq_read,
.llseek = seq_lseek,
.release = single_release,
};
static int __init cpa_stats_init(void)
{
debugfs_create_file("cpa_stats", S_IRUSR, arch_debugfs_dir, NULL,
&cpastats_fops);
return 0;
}
late_initcall(cpa_stats_init);
#else
static inline void cpa_inc_1g_checked(void) { }
static inline void cpa_inc_2m_checked(void) { }
static inline void cpa_inc_4k_install(void) { }
static inline void cpa_inc_lp_sameprot(int level) { }
static inline void cpa_inc_lp_preserved(int level) { }
#endif
static inline int
within(unsigned long addr, unsigned long start, unsigned long end)
{
return addr >= start && addr < end;
}
static inline int
within_inclusive(unsigned long addr, unsigned long start, unsigned long end)
{
return addr >= start && addr <= end;
}
#ifdef CONFIG_X86_64
/*
* The kernel image is mapped into two places in the virtual address space
* (addresses without KASLR, of course):
*
* 1. The kernel direct map (0xffff880000000000)
* 2. The "high kernel map" (0xffffffff81000000)
*
* We actually execute out of #2. If we get the address of a kernel symbol, it
* points to #2, but almost all physical-to-virtual translations point to #1.
*
* This is so that we can have both a directmap of all physical memory *and*
* take full advantage of the the limited (s32) immediate addressing range (2G)
* of x86_64.
*
* See Documentation/x86/x86_64/mm.rst for more detail.
*/
static inline unsigned long highmap_start_pfn(void)
{
return __pa_symbol(_text) >> PAGE_SHIFT;
}
static inline unsigned long highmap_end_pfn(void)
{
/* Do not reference physical address outside the kernel. */
return __pa_symbol(roundup(_brk_end, PMD_SIZE) - 1) >> PAGE_SHIFT;
}
static bool __cpa_pfn_in_highmap(unsigned long pfn)
{
/*
* Kernel text has an alias mapping at a high address, known
* here as "highmap".
*/
return within_inclusive(pfn, highmap_start_pfn(), highmap_end_pfn());
}
#else
static bool __cpa_pfn_in_highmap(unsigned long pfn)
{
/* There is no highmap on 32-bit */
return false;
}
#endif
/*
* See set_mce_nospec().
*
* Machine check recovery code needs to change cache mode of poisoned pages to
* UC to avoid speculative access logging another error. But passing the
* address of the 1:1 mapping to set_memory_uc() is a fine way to encourage a
* speculative access. So we cheat and flip the top bit of the address. This
* works fine for the code that updates the page tables. But at the end of the
* process we need to flush the TLB and cache and the non-canonical address
* causes a #GP fault when used by the INVLPG and CLFLUSH instructions.
*
* But in the common case we already have a canonical address. This code
* will fix the top bit if needed and is a no-op otherwise.
*/
static inline unsigned long fix_addr(unsigned long addr)
{
#ifdef CONFIG_X86_64
return (long)(addr << 1) >> 1;
#else
return addr;
#endif
}
static unsigned long __cpa_addr(struct cpa_data *cpa, unsigned long idx)
{
if (cpa->flags & CPA_PAGES_ARRAY) {
struct page *page = cpa->pages[idx];
if (unlikely(PageHighMem(page)))
return 0;
return (unsigned long)page_address(page);
}
if (cpa->flags & CPA_ARRAY)
return cpa->vaddr[idx];
return *cpa->vaddr + idx * PAGE_SIZE;
}
/*
* Flushing functions
*/
static void clflush_cache_range_opt(void *vaddr, unsigned int size)
{
const unsigned long clflush_size = boot_cpu_data.x86_clflush_size;
void *p = (void *)((unsigned long)vaddr & ~(clflush_size - 1));
void *vend = vaddr + size;
if (p >= vend)
return;
for (; p < vend; p += clflush_size)
clflushopt(p);
}
/**
* clflush_cache_range - flush a cache range with clflush
* @vaddr: virtual start address
* @size: number of bytes to flush
*
* CLFLUSHOPT is an unordered instruction which needs fencing with MFENCE or
* SFENCE to avoid ordering issues.
*/
void clflush_cache_range(void *vaddr, unsigned int size)
{
mb();
clflush_cache_range_opt(vaddr, size);
mb();
}
EXPORT_SYMBOL_GPL(clflush_cache_range);
#ifdef CONFIG_ARCH_HAS_PMEM_API
void arch_invalidate_pmem(void *addr, size_t size)
{
clflush_cache_range(addr, size);
}
EXPORT_SYMBOL_GPL(arch_invalidate_pmem);
#endif
#ifdef CONFIG_ARCH_HAS_CPU_CACHE_INVALIDATE_MEMREGION
bool cpu_cache_has_invalidate_memregion(void)
{
return !cpu_feature_enabled(X86_FEATURE_HYPERVISOR);
}
EXPORT_SYMBOL_NS_GPL(cpu_cache_has_invalidate_memregion, DEVMEM);
int cpu_cache_invalidate_memregion(int res_desc)
{
if (WARN_ON_ONCE(!cpu_cache_has_invalidate_memregion()))
return -ENXIO;
wbinvd_on_all_cpus();
return 0;
}
EXPORT_SYMBOL_NS_GPL(cpu_cache_invalidate_memregion, DEVMEM);
#endif
static void __cpa_flush_all(void *arg)
{
unsigned long cache = (unsigned long)arg;
/*
* Flush all to work around Errata in early athlons regarding
* large page flushing.
*/
__flush_tlb_all();
if (cache && boot_cpu_data.x86 >= 4)
wbinvd();
}
static void cpa_flush_all(unsigned long cache)
{
BUG_ON(irqs_disabled() && !early_boot_irqs_disabled);
on_each_cpu(__cpa_flush_all, (void *) cache, 1);
}
static void __cpa_flush_tlb(void *data)
{
struct cpa_data *cpa = data;
unsigned int i;
for (i = 0; i < cpa->numpages; i++)
flush_tlb_one_kernel(fix_addr(__cpa_addr(cpa, i)));
}
static void cpa_flush(struct cpa_data *data, int cache)
{
struct cpa_data *cpa = data;
unsigned int i;
BUG_ON(irqs_disabled() && !early_boot_irqs_disabled);
if (cache && !static_cpu_has(X86_FEATURE_CLFLUSH)) {
cpa_flush_all(cache);
return;
}
if (cpa->force_flush_all || cpa->numpages > tlb_single_page_flush_ceiling)
flush_tlb_all();
else
on_each_cpu(__cpa_flush_tlb, cpa, 1);
if (!cache)
return;
mb();
for (i = 0; i < cpa->numpages; i++) {
unsigned long addr = __cpa_addr(cpa, i);
unsigned int level;
pte_t *pte = lookup_address(addr, &level);
/*
* Only flush present addresses:
*/
if (pte && (pte_val(*pte) & _PAGE_PRESENT))
clflush_cache_range_opt((void *)fix_addr(addr), PAGE_SIZE);
}
mb();
}
static bool overlaps(unsigned long r1_start, unsigned long r1_end,
unsigned long r2_start, unsigned long r2_end)
{
return (r1_start <= r2_end && r1_end >= r2_start) ||
(r2_start <= r1_end && r2_end >= r1_start);
}
#ifdef CONFIG_PCI_BIOS
/*
* The BIOS area between 640k and 1Mb needs to be executable for PCI BIOS
* based config access (CONFIG_PCI_GOBIOS) support.
*/
#define BIOS_PFN PFN_DOWN(BIOS_BEGIN)
#define BIOS_PFN_END PFN_DOWN(BIOS_END - 1)
static pgprotval_t protect_pci_bios(unsigned long spfn, unsigned long epfn)
{
if (pcibios_enabled && overlaps(spfn, epfn, BIOS_PFN, BIOS_PFN_END))
return _PAGE_NX;
return 0;
}
#else
static pgprotval_t protect_pci_bios(unsigned long spfn, unsigned long epfn)
{
return 0;
}
#endif
/*
* The .rodata section needs to be read-only. Using the pfn catches all
* aliases. This also includes __ro_after_init, so do not enforce until
* kernel_set_to_readonly is true.
*/
static pgprotval_t protect_rodata(unsigned long spfn, unsigned long epfn)
{
unsigned long epfn_ro, spfn_ro = PFN_DOWN(__pa_symbol(__start_rodata));
/*
* Note: __end_rodata is at page aligned and not inclusive, so
* subtract 1 to get the last enforced PFN in the rodata area.
*/
epfn_ro = PFN_DOWN(__pa_symbol(__end_rodata)) - 1;
if (kernel_set_to_readonly && overlaps(spfn, epfn, spfn_ro, epfn_ro))
return _PAGE_RW;
return 0;
}
/*
* Protect kernel text against becoming non executable by forbidding
* _PAGE_NX. This protects only the high kernel mapping (_text -> _etext)
* out of which the kernel actually executes. Do not protect the low
* mapping.
*
* This does not cover __inittext since that is gone after boot.
*/
static pgprotval_t protect_kernel_text(unsigned long start, unsigned long end)
{
unsigned long t_end = (unsigned long)_etext - 1;
unsigned long t_start = (unsigned long)_text;
if (overlaps(start, end, t_start, t_end))
return _PAGE_NX;
return 0;
}
#if defined(CONFIG_X86_64)
/*
* Once the kernel maps the text as RO (kernel_set_to_readonly is set),
* kernel text mappings for the large page aligned text, rodata sections
* will be always read-only. For the kernel identity mappings covering the
* holes caused by this alignment can be anything that user asks.
*
* This will preserve the large page mappings for kernel text/data at no
* extra cost.
*/
static pgprotval_t protect_kernel_text_ro(unsigned long start,
unsigned long end)
{
unsigned long t_end = (unsigned long)__end_rodata_hpage_align - 1;
unsigned long t_start = (unsigned long)_text;
unsigned int level;
if (!kernel_set_to_readonly || !overlaps(start, end, t_start, t_end))
return 0;
/*
* Don't enforce the !RW mapping for the kernel text mapping, if
* the current mapping is already using small page mapping. No
* need to work hard to preserve large page mappings in this case.
*
* This also fixes the Linux Xen paravirt guest boot failure caused
* by unexpected read-only mappings for kernel identity
* mappings. In this paravirt guest case, the kernel text mapping
* and the kernel identity mapping share the same page-table pages,
* so the protections for kernel text and identity mappings have to
* be the same.
*/
if (lookup_address(start, &level) && (level != PG_LEVEL_4K))
return _PAGE_RW;
return 0;
}
#else
static pgprotval_t protect_kernel_text_ro(unsigned long start,
unsigned long end)
{
return 0;
}
#endif
static inline bool conflicts(pgprot_t prot, pgprotval_t val)
{
return (pgprot_val(prot) & ~val) != pgprot_val(prot);
}
static inline void check_conflict(int warnlvl, pgprot_t prot, pgprotval_t val,
unsigned long start, unsigned long end,
unsigned long pfn, const char *txt)
{
static const char *lvltxt[] = {
[CPA_CONFLICT] = "conflict",
[CPA_PROTECT] = "protect",
[CPA_DETECT] = "detect",
};
if (warnlvl > cpa_warn_level || !conflicts(prot, val))
return;
pr_warn("CPA %8s %10s: 0x%016lx - 0x%016lx PFN %lx req %016llx prevent %016llx\n",
lvltxt[warnlvl], txt, start, end, pfn, (unsigned long long)pgprot_val(prot),
(unsigned long long)val);
}
/*
* Certain areas of memory on x86 require very specific protection flags,
* for example the BIOS area or kernel text. Callers don't always get this
* right (again, ioremap() on BIOS memory is not uncommon) so this function
* checks and fixes these known static required protection bits.
*/
static inline pgprot_t static_protections(pgprot_t prot, unsigned long start,
unsigned long pfn, unsigned long npg,
unsigned long lpsize, int warnlvl)
{
pgprotval_t forbidden, res;
unsigned long end;
/*
* There is no point in checking RW/NX conflicts when the requested
* mapping is setting the page !PRESENT.
*/
if (!(pgprot_val(prot) & _PAGE_PRESENT))
return prot;
/* Operate on the virtual address */
end = start + npg * PAGE_SIZE - 1;
res = protect_kernel_text(start, end);
check_conflict(warnlvl, prot, res, start, end, pfn, "Text NX");
forbidden = res;
/*
* Special case to preserve a large page. If the change spawns the
* full large page mapping then there is no point to split it
* up. Happens with ftrace and is going to be removed once ftrace
* switched to text_poke().
*/
if (lpsize != (npg * PAGE_SIZE) || (start & (lpsize - 1))) {
res = protect_kernel_text_ro(start, end);
check_conflict(warnlvl, prot, res, start, end, pfn, "Text RO");
forbidden |= res;
}
/* Check the PFN directly */
res = protect_pci_bios(pfn, pfn + npg - 1);
check_conflict(warnlvl, prot, res, start, end, pfn, "PCIBIOS NX");
forbidden |= res;
res = protect_rodata(pfn, pfn + npg - 1);
check_conflict(warnlvl, prot, res, start, end, pfn, "Rodata RO");
forbidden |= res;
return __pgprot(pgprot_val(prot) & ~forbidden);
}
/*
* Validate strict W^X semantics.
*/
static inline pgprot_t verify_rwx(pgprot_t old, pgprot_t new, unsigned long start,
unsigned long pfn, unsigned long npg)
{
unsigned long end;
/*
* 32-bit has some unfixable W+X issues, like EFI code
* and writeable data being in the same page. Disable
* detection and enforcement there.
*/
if (IS_ENABLED(CONFIG_X86_32))
return new;
/* Only verify when NX is supported: */
if (!(__supported_pte_mask & _PAGE_NX))
return new;
if (!((pgprot_val(old) ^ pgprot_val(new)) & (_PAGE_RW | _PAGE_NX)))
return new;
if ((pgprot_val(new) & (_PAGE_RW | _PAGE_NX)) != _PAGE_RW)
return new;
end = start + npg * PAGE_SIZE - 1;
WARN_ONCE(1, "CPA detected W^X violation: %016llx -> %016llx range: 0x%016lx - 0x%016lx PFN %lx\n",
(unsigned long long)pgprot_val(old),
(unsigned long long)pgprot_val(new),
start, end, pfn);
/*
* For now, allow all permission change attempts by returning the
* attempted permissions. This can 'return old' to actively
* refuse the permission change at a later time.
*/
return new;
}
/*
* Lookup the page table entry for a virtual address in a specific pgd.
* Return a pointer to the entry and the level of the mapping.
*/
pte_t *lookup_address_in_pgd(pgd_t *pgd, unsigned long address,
unsigned int *level)
{
p4d_t *p4d;
pud_t *pud;
pmd_t *pmd;
*level = PG_LEVEL_NONE;
if (pgd_none(*pgd))
return NULL;
p4d = p4d_offset(pgd, address);
if (p4d_none(*p4d))
return NULL;
*level = PG_LEVEL_512G;
if (p4d_large(*p4d) || !p4d_present(*p4d))
return (pte_t *)p4d;
pud = pud_offset(p4d, address);
if (pud_none(*pud))
return NULL;
*level = PG_LEVEL_1G;
if (pud_large(*pud) || !pud_present(*pud))
return (pte_t *)pud;
pmd = pmd_offset(pud, address);
if (pmd_none(*pmd))
return NULL;
*level = PG_LEVEL_2M;
if (pmd_large(*pmd) || !pmd_present(*pmd))
return (pte_t *)pmd;
*level = PG_LEVEL_4K;
return pte_offset_kernel(pmd, address);
}
/*
* Lookup the page table entry for a virtual address. Return a pointer
* to the entry and the level of the mapping.
*
* Note: We return pud and pmd either when the entry is marked large
* or when the present bit is not set. Otherwise we would return a
* pointer to a nonexisting mapping.
*/
pte_t *lookup_address(unsigned long address, unsigned int *level)
{
return lookup_address_in_pgd(pgd_offset_k(address), address, level);
}
EXPORT_SYMBOL_GPL(lookup_address);
static pte_t *_lookup_address_cpa(struct cpa_data *cpa, unsigned long address,
unsigned int *level)
{
if (cpa->pgd)
return lookup_address_in_pgd(cpa->pgd + pgd_index(address),
address, level);
return lookup_address(address, level);
}
/*
* Lookup the PMD entry for a virtual address. Return a pointer to the entry
* or NULL if not present.
*/
pmd_t *lookup_pmd_address(unsigned long address)
{
pgd_t *pgd;
p4d_t *p4d;
pud_t *pud;
pgd = pgd_offset_k(address);
if (pgd_none(*pgd))
return NULL;
p4d = p4d_offset(pgd, address);
if (p4d_none(*p4d) || p4d_large(*p4d) || !p4d_present(*p4d))
return NULL;
pud = pud_offset(p4d, address);
if (pud_none(*pud) || pud_large(*pud) || !pud_present(*pud))
return NULL;
return pmd_offset(pud, address);
}
/*
* This is necessary because __pa() does not work on some
* kinds of memory, like vmalloc() or the alloc_remap()
* areas on 32-bit NUMA systems. The percpu areas can
* end up in this kind of memory, for instance.
*
* This could be optimized, but it is only intended to be
* used at initialization time, and keeping it
* unoptimized should increase the testing coverage for
* the more obscure platforms.
*/
phys_addr_t slow_virt_to_phys(void *__virt_addr)
{
unsigned long virt_addr = (unsigned long)__virt_addr;
phys_addr_t phys_addr;
unsigned long offset;
enum pg_level level;
pte_t *pte;
pte = lookup_address(virt_addr, &level);
BUG_ON(!pte);
/*
* pXX_pfn() returns unsigned long, which must be cast to phys_addr_t
* before being left-shifted PAGE_SHIFT bits -- this trick is to
* make 32-PAE kernel work correctly.
*/
switch (level) {
case PG_LEVEL_1G:
phys_addr = (phys_addr_t)pud_pfn(*(pud_t *)pte) << PAGE_SHIFT;
offset = virt_addr & ~PUD_MASK;
break;
case PG_LEVEL_2M:
phys_addr = (phys_addr_t)pmd_pfn(*(pmd_t *)pte) << PAGE_SHIFT;
offset = virt_addr & ~PMD_MASK;
break;
default:
phys_addr = (phys_addr_t)pte_pfn(*pte) << PAGE_SHIFT;
offset = virt_addr & ~PAGE_MASK;
}
return (phys_addr_t)(phys_addr | offset);
}
EXPORT_SYMBOL_GPL(slow_virt_to_phys);
/*
* Set the new pmd in all the pgds we know about:
*/
static void __set_pmd_pte(pte_t *kpte, unsigned long address, pte_t pte)
{
/* change init_mm */
set_pte_atomic(kpte, pte);
#ifdef CONFIG_X86_32
if (!SHARED_KERNEL_PMD) {
struct page *page;
list_for_each_entry(page, &pgd_list, lru) {
pgd_t *pgd;
p4d_t *p4d;
pud_t *pud;
pmd_t *pmd;
pgd = (pgd_t *)page_address(page) + pgd_index(address);
p4d = p4d_offset(pgd, address);
pud = pud_offset(p4d, address);
pmd = pmd_offset(pud, address);
set_pte_atomic((pte_t *)pmd, pte);
}
}
#endif
}
static pgprot_t pgprot_clear_protnone_bits(pgprot_t prot)
{
/*
* _PAGE_GLOBAL means "global page" for present PTEs.
* But, it is also used to indicate _PAGE_PROTNONE
* for non-present PTEs.
*
* This ensures that a _PAGE_GLOBAL PTE going from
* present to non-present is not confused as
* _PAGE_PROTNONE.
*/
if (!(pgprot_val(prot) & _PAGE_PRESENT))
pgprot_val(prot) &= ~_PAGE_GLOBAL;
return prot;
}
static int __should_split_large_page(pte_t *kpte, unsigned long address,
struct cpa_data *cpa)
{
unsigned long numpages, pmask, psize, lpaddr, pfn, old_pfn;
pgprot_t old_prot, new_prot, req_prot, chk_prot;
pte_t new_pte, *tmp;
enum pg_level level;
/*
* Check for races, another CPU might have split this page
* up already:
*/
tmp = _lookup_address_cpa(cpa, address, &level);
if (tmp != kpte)
return 1;
switch (level) {
case PG_LEVEL_2M:
old_prot = pmd_pgprot(*(pmd_t *)kpte);
old_pfn = pmd_pfn(*(pmd_t *)kpte);
cpa_inc_2m_checked();
break;
case PG_LEVEL_1G:
old_prot = pud_pgprot(*(pud_t *)kpte);
old_pfn = pud_pfn(*(pud_t *)kpte);
cpa_inc_1g_checked();
break;
default:
return -EINVAL;
}
psize = page_level_size(level);
pmask = page_level_mask(level);
/*
* Calculate the number of pages, which fit into this large
* page starting at address:
*/
lpaddr = (address + psize) & pmask;
numpages = (lpaddr - address) >> PAGE_SHIFT;
if (numpages < cpa->numpages)
cpa->numpages = numpages;
/*
* We are safe now. Check whether the new pgprot is the same:
* Convert protection attributes to 4k-format, as cpa->mask* are set
* up accordingly.
*/
/* Clear PSE (aka _PAGE_PAT) and move PAT bit to correct position */
req_prot = pgprot_large_2_4k(old_prot);
pgprot_val(req_prot) &= ~pgprot_val(cpa->mask_clr);
pgprot_val(req_prot) |= pgprot_val(cpa->mask_set);
/*
* req_prot is in format of 4k pages. It must be converted to large
* page format: the caching mode includes the PAT bit located at
* different bit positions in the two formats.
*/
req_prot = pgprot_4k_2_large(req_prot);
req_prot = pgprot_clear_protnone_bits(req_prot);
if (pgprot_val(req_prot) & _PAGE_PRESENT)
pgprot_val(req_prot) |= _PAGE_PSE;
/*
* old_pfn points to the large page base pfn. So we need to add the
* offset of the virtual address:
*/
pfn = old_pfn + ((address & (psize - 1)) >> PAGE_SHIFT);
cpa->pfn = pfn;
/*
* Calculate the large page base address and the number of 4K pages
* in the large page
*/
lpaddr = address & pmask;
numpages = psize >> PAGE_SHIFT;
/*
* Sanity check that the existing mapping is correct versus the static
* protections. static_protections() guards against !PRESENT, so no
* extra conditional required here.
*/
chk_prot = static_protections(old_prot, lpaddr, old_pfn, numpages,
psize, CPA_CONFLICT);
if (WARN_ON_ONCE(pgprot_val(chk_prot) != pgprot_val(old_prot))) {
/*
* Split the large page and tell the split code to
* enforce static protections.
*/
cpa->force_static_prot = 1;
return 1;
}
/*
* Optimization: If the requested pgprot is the same as the current
* pgprot, then the large page can be preserved and no updates are
* required independent of alignment and length of the requested
* range. The above already established that the current pgprot is
* correct, which in consequence makes the requested pgprot correct
* as well if it is the same. The static protection scan below will
* not come to a different conclusion.
*/
if (pgprot_val(req_prot) == pgprot_val(old_prot)) {
cpa_inc_lp_sameprot(level);
return 0;
}
/*
* If the requested range does not cover the full page, split it up
*/
if (address != lpaddr || cpa->numpages != numpages)
return 1;
/*
* Check whether the requested pgprot is conflicting with a static
* protection requirement in the large page.
*/
new_prot = static_protections(req_prot, lpaddr, old_pfn, numpages,
psize, CPA_DETECT);
new_prot = verify_rwx(old_prot, new_prot, lpaddr, old_pfn, numpages);
/*
* If there is a conflict, split the large page.
*
* There used to be a 4k wise evaluation trying really hard to
* preserve the large pages, but experimentation has shown, that this
* does not help at all. There might be corner cases which would
* preserve one large page occasionally, but it's really not worth the
* extra code and cycles for the common case.
*/
if (pgprot_val(req_prot) != pgprot_val(new_prot))
return 1;
/* All checks passed. Update the large page mapping. */
new_pte = pfn_pte(old_pfn, new_prot);
__set_pmd_pte(kpte, address, new_pte);
cpa->flags |= CPA_FLUSHTLB;
cpa_inc_lp_preserved(level);
return 0;
}
static int should_split_large_page(pte_t *kpte, unsigned long address,
struct cpa_data *cpa)
{
int do_split;
if (cpa->force_split)
return 1;
spin_lock(&pgd_lock);
do_split = __should_split_large_page(kpte, address, cpa);
spin_unlock(&pgd_lock);
return do_split;
}
static void split_set_pte(struct cpa_data *cpa, pte_t *pte, unsigned long pfn,
pgprot_t ref_prot, unsigned long address,
unsigned long size)
{
unsigned int npg = PFN_DOWN(size);
pgprot_t prot;
/*
* If should_split_large_page() discovered an inconsistent mapping,
* remove the invalid protection in the split mapping.
*/
if (!cpa->force_static_prot)
goto set;
/* Hand in lpsize = 0 to enforce the protection mechanism */
prot = static_protections(ref_prot, address, pfn, npg, 0, CPA_PROTECT);
if (pgprot_val(prot) == pgprot_val(ref_prot))
goto set;
/*
* If this is splitting a PMD, fix it up. PUD splits cannot be
* fixed trivially as that would require to rescan the newly
* installed PMD mappings after returning from split_large_page()
* so an eventual further split can allocate the necessary PTE
* pages. Warn for now and revisit it in case this actually
* happens.
*/
if (size == PAGE_SIZE)
ref_prot = prot;
else
pr_warn_once("CPA: Cannot fixup static protections for PUD split\n");
set:
set_pte(pte, pfn_pte(pfn, ref_prot));
}
static int
__split_large_page(struct cpa_data *cpa, pte_t *kpte, unsigned long address,
struct page *base)
{
unsigned long lpaddr, lpinc, ref_pfn, pfn, pfninc = 1;
pte_t *pbase = (pte_t *)page_address(base);
unsigned int i, level;
pgprot_t ref_prot;
pte_t *tmp;
spin_lock(&pgd_lock);
/*
* Check for races, another CPU might have split this page
* up for us already:
*/
tmp = _lookup_address_cpa(cpa, address, &level);
if (tmp != kpte) {
spin_unlock(&pgd_lock);
return 1;
}
paravirt_alloc_pte(&init_mm, page_to_pfn(base));
switch (level) {
case PG_LEVEL_2M:
ref_prot = pmd_pgprot(*(pmd_t *)kpte);
/*
* Clear PSE (aka _PAGE_PAT) and move
* PAT bit to correct position.
*/
ref_prot = pgprot_large_2_4k(ref_prot);
ref_pfn = pmd_pfn(*(pmd_t *)kpte);
lpaddr = address & PMD_MASK;
lpinc = PAGE_SIZE;
break;
case PG_LEVEL_1G:
ref_prot = pud_pgprot(*(pud_t *)kpte);
ref_pfn = pud_pfn(*(pud_t *)kpte);
pfninc = PMD_SIZE >> PAGE_SHIFT;
lpaddr = address & PUD_MASK;
lpinc = PMD_SIZE;
/*
* Clear the PSE flags if the PRESENT flag is not set
* otherwise pmd_present/pmd_huge will return true
* even on a non present pmd.
*/
if (!(pgprot_val(ref_prot) & _PAGE_PRESENT))
pgprot_val(ref_prot) &= ~_PAGE_PSE;
break;
default:
spin_unlock(&pgd_lock);
return 1;
}
ref_prot = pgprot_clear_protnone_bits(ref_prot);
/*
* Get the target pfn from the original entry:
*/
pfn = ref_pfn;
for (i = 0; i < PTRS_PER_PTE; i++, pfn += pfninc, lpaddr += lpinc)
split_set_pte(cpa, pbase + i, pfn, ref_prot, lpaddr, lpinc);
if (virt_addr_valid(address)) {
unsigned long pfn = PFN_DOWN(__pa(address));
if (pfn_range_is_mapped(pfn, pfn + 1))
split_page_count(level);
}
/*
* Install the new, split up pagetable.
*
* We use the standard kernel pagetable protections for the new
* pagetable protections, the actual ptes set above control the
* primary protection behavior:
*/
__set_pmd_pte(kpte, address, mk_pte(base, __pgprot(_KERNPG_TABLE)));
/*
* Do a global flush tlb after splitting the large page
* and before we do the actual change page attribute in the PTE.
*
* Without this, we violate the TLB application note, that says:
* "The TLBs may contain both ordinary and large-page
* translations for a 4-KByte range of linear addresses. This
* may occur if software modifies the paging structures so that
* the page size used for the address range changes. If the two
* translations differ with respect to page frame or attributes
* (e.g., permissions), processor behavior is undefined and may
* be implementation-specific."
*
* We do this global tlb flush inside the cpa_lock, so that we
* don't allow any other cpu, with stale tlb entries change the
* page attribute in parallel, that also falls into the
* just split large page entry.
*/
flush_tlb_all();
spin_unlock(&pgd_lock);
return 0;
}
static int split_large_page(struct cpa_data *cpa, pte_t *kpte,
unsigned long address)
{
struct page *base;
if (!debug_pagealloc_enabled())
spin_unlock(&cpa_lock);
base = alloc_pages(GFP_KERNEL, 0);
if (!debug_pagealloc_enabled())
spin_lock(&cpa_lock);
if (!base)
return -ENOMEM;
if (__split_large_page(cpa, kpte, address, base))
__free_page(base);
return 0;
}
static bool try_to_free_pte_page(pte_t *pte)
{
int i;
for (i = 0; i < PTRS_PER_PTE; i++)
if (!pte_none(pte[i]))
return false;
free_page((unsigned long)pte);
return true;
}
static bool try_to_free_pmd_page(pmd_t *pmd)
{
int i;
for (i = 0; i < PTRS_PER_PMD; i++)
if (!pmd_none(pmd[i]))
return false;
free_page((unsigned long)pmd);
return true;
}
static bool unmap_pte_range(pmd_t *pmd, unsigned long start, unsigned long end)
{
pte_t *pte = pte_offset_kernel(pmd, start);
while (start < end) {
set_pte(pte, __pte(0));
start += PAGE_SIZE;
pte++;
}
if (try_to_free_pte_page((pte_t *)pmd_page_vaddr(*pmd))) {
pmd_clear(pmd);
return true;
}
return false;
}
static void __unmap_pmd_range(pud_t *pud, pmd_t *pmd,
unsigned long start, unsigned long end)
{
if (unmap_pte_range(pmd, start, end))
if (try_to_free_pmd_page(pud_pgtable(*pud)))
pud_clear(pud);
}
static void unmap_pmd_range(pud_t *pud, unsigned long start, unsigned long end)
{
pmd_t *pmd = pmd_offset(pud, start);
/*
* Not on a 2MB page boundary?
*/
if (start & (PMD_SIZE - 1)) {
unsigned long next_page = (start + PMD_SIZE) & PMD_MASK;
unsigned long pre_end = min_t(unsigned long, end, next_page);
__unmap_pmd_range(pud, pmd, start, pre_end);
start = pre_end;
pmd++;
}
/*
* Try to unmap in 2M chunks.
*/
while (end - start >= PMD_SIZE) {
if (pmd_large(*pmd))
pmd_clear(pmd);
else
__unmap_pmd_range(pud, pmd, start, start + PMD_SIZE);
start += PMD_SIZE;
pmd++;
}
/*
* 4K leftovers?
*/
if (start < end)
return __unmap_pmd_range(pud, pmd, start, end);
/*
* Try again to free the PMD page if haven't succeeded above.
*/
if (!pud_none(*pud))
if (try_to_free_pmd_page(pud_pgtable(*pud)))
pud_clear(pud);
}
static void unmap_pud_range(p4d_t *p4d, unsigned long start, unsigned long end)
{
pud_t *pud = pud_offset(p4d, start);
/*
* Not on a GB page boundary?
*/
if (start & (PUD_SIZE - 1)) {
unsigned long next_page = (start + PUD_SIZE) & PUD_MASK;
unsigned long pre_end = min_t(unsigned long, end, next_page);
unmap_pmd_range(pud, start, pre_end);
start = pre_end;
pud++;
}
/*
* Try to unmap in 1G chunks?
*/
while (end - start >= PUD_SIZE) {
if (pud_large(*pud))
pud_clear(pud);
else
unmap_pmd_range(pud, start, start + PUD_SIZE);
start += PUD_SIZE;
pud++;
}
/*
* 2M leftovers?
*/
if (start < end)
unmap_pmd_range(pud, start, end);
/*
* No need to try to free the PUD page because we'll free it in
* populate_pgd's error path
*/
}
static int alloc_pte_page(pmd_t *pmd)
{
pte_t *pte = (pte_t *)get_zeroed_page(GFP_KERNEL);
if (!pte)
return -1;
set_pmd(pmd, __pmd(__pa(pte) | _KERNPG_TABLE));
return 0;
}
static int alloc_pmd_page(pud_t *pud)
{
pmd_t *pmd = (pmd_t *)get_zeroed_page(GFP_KERNEL);
if (!pmd)
return -1;
set_pud(pud, __pud(__pa(pmd) | _KERNPG_TABLE));
return 0;
}
static void populate_pte(struct cpa_data *cpa,
unsigned long start, unsigned long end,
unsigned num_pages, pmd_t *pmd, pgprot_t pgprot)
{
pte_t *pte;
pte = pte_offset_kernel(pmd, start);
pgprot = pgprot_clear_protnone_bits(pgprot);
while (num_pages-- && start < end) {
set_pte(pte, pfn_pte(cpa->pfn, pgprot));
start += PAGE_SIZE;
cpa->pfn++;
pte++;
}
}
static long populate_pmd(struct cpa_data *cpa,
unsigned long start, unsigned long end,
unsigned num_pages, pud_t *pud, pgprot_t pgprot)
{
long cur_pages = 0;
pmd_t *pmd;
pgprot_t pmd_pgprot;
/*
* Not on a 2M boundary?
*/
if (start & (PMD_SIZE - 1)) {
unsigned long pre_end = start + (num_pages << PAGE_SHIFT);
unsigned long next_page = (start + PMD_SIZE) & PMD_MASK;
pre_end = min_t(unsigned long, pre_end, next_page);
cur_pages = (pre_end - start) >> PAGE_SHIFT;
cur_pages = min_t(unsigned int, num_pages, cur_pages);
/*
* Need a PTE page?
*/
pmd = pmd_offset(pud, start);
if (pmd_none(*pmd))
if (alloc_pte_page(pmd))
return -1;
populate_pte(cpa, start, pre_end, cur_pages, pmd, pgprot);
start = pre_end;
}
/*
* We mapped them all?
*/
if (num_pages == cur_pages)
return cur_pages;
pmd_pgprot = pgprot_4k_2_large(pgprot);
while (end - start >= PMD_SIZE) {
/*
* We cannot use a 1G page so allocate a PMD page if needed.
*/
if (pud_none(*pud))
if (alloc_pmd_page(pud))
return -1;
pmd = pmd_offset(pud, start);
set_pmd(pmd, pmd_mkhuge(pfn_pmd(cpa->pfn,
canon_pgprot(pmd_pgprot))));
start += PMD_SIZE;
cpa->pfn += PMD_SIZE >> PAGE_SHIFT;
cur_pages += PMD_SIZE >> PAGE_SHIFT;
}
/*
* Map trailing 4K pages.
*/
if (start < end) {
pmd = pmd_offset(pud, start);
if (pmd_none(*pmd))
if (alloc_pte_page(pmd))
return -1;
populate_pte(cpa, start, end, num_pages - cur_pages,
pmd, pgprot);
}
return num_pages;
}
static int populate_pud(struct cpa_data *cpa, unsigned long start, p4d_t *p4d,
pgprot_t pgprot)
{
pud_t *pud;
unsigned long end;
long cur_pages = 0;
pgprot_t pud_pgprot;
end = start + (cpa->numpages << PAGE_SHIFT);
/*
* Not on a Gb page boundary? => map everything up to it with
* smaller pages.
*/
if (start & (PUD_SIZE - 1)) {
unsigned long pre_end;
unsigned long next_page = (start + PUD_SIZE) & PUD_MASK;
pre_end = min_t(unsigned long, end, next_page);
cur_pages = (pre_end - start) >> PAGE_SHIFT;
cur_pages = min_t(int, (int)cpa->numpages, cur_pages);
pud = pud_offset(p4d, start);
/*
* Need a PMD page?
*/
if (pud_none(*pud))
if (alloc_pmd_page(pud))
return -1;
cur_pages = populate_pmd(cpa, start, pre_end, cur_pages,
pud, pgprot);
if (cur_pages < 0)
return cur_pages;
start = pre_end;
}
/* We mapped them all? */
if (cpa->numpages == cur_pages)
return cur_pages;
pud = pud_offset(p4d, start);
pud_pgprot = pgprot_4k_2_large(pgprot);
/*
* Map everything starting from the Gb boundary, possibly with 1G pages
*/
while (boot_cpu_has(X86_FEATURE_GBPAGES) && end - start >= PUD_SIZE) {
set_pud(pud, pud_mkhuge(pfn_pud(cpa->pfn,
canon_pgprot(pud_pgprot))));
start += PUD_SIZE;
cpa->pfn += PUD_SIZE >> PAGE_SHIFT;
cur_pages += PUD_SIZE >> PAGE_SHIFT;
pud++;
}
/* Map trailing leftover */
if (start < end) {
long tmp;
pud = pud_offset(p4d, start);
if (pud_none(*pud))
if (alloc_pmd_page(pud))
return -1;
tmp = populate_pmd(cpa, start, end, cpa->numpages - cur_pages,
pud, pgprot);
if (tmp < 0)
return cur_pages;
cur_pages += tmp;
}
return cur_pages;
}
/*
* Restrictions for kernel page table do not necessarily apply when mapping in
* an alternate PGD.
*/
static int populate_pgd(struct cpa_data *cpa, unsigned long addr)
{
pgprot_t pgprot = __pgprot(_KERNPG_TABLE);
pud_t *pud = NULL; /* shut up gcc */
p4d_t *p4d;
pgd_t *pgd_entry;
long ret;
pgd_entry = cpa->pgd + pgd_index(addr);
if (pgd_none(*pgd_entry)) {
p4d = (p4d_t *)get_zeroed_page(GFP_KERNEL);
if (!p4d)
return -1;
set_pgd(pgd_entry, __pgd(__pa(p4d) | _KERNPG_TABLE));
}
/*
* Allocate a PUD page and hand it down for mapping.
*/
p4d = p4d_offset(pgd_entry, addr);
if (p4d_none(*p4d)) {
pud = (pud_t *)get_zeroed_page(GFP_KERNEL);
if (!pud)
return -1;
set_p4d(p4d, __p4d(__pa(pud) | _KERNPG_TABLE));
}
pgprot_val(pgprot) &= ~pgprot_val(cpa->mask_clr);
pgprot_val(pgprot) |= pgprot_val(cpa->mask_set);
ret = populate_pud(cpa, addr, p4d, pgprot);
if (ret < 0) {
/*
* Leave the PUD page in place in case some other CPU or thread
* already found it, but remove any useless entries we just
* added to it.
*/
unmap_pud_range(p4d, addr,
addr + (cpa->numpages << PAGE_SHIFT));
return ret;
}
cpa->numpages = ret;
return 0;
}
static int __cpa_process_fault(struct cpa_data *cpa, unsigned long vaddr,
int primary)
{
if (cpa->pgd) {
/*
* Right now, we only execute this code path when mapping
* the EFI virtual memory map regions, no other users
* provide a ->pgd value. This may change in the future.
*/
return populate_pgd(cpa, vaddr);
}
/*
* Ignore all non primary paths.
*/
if (!primary) {
cpa->numpages = 1;
return 0;
}
/*
* Ignore the NULL PTE for kernel identity mapping, as it is expected
* to have holes.
* Also set numpages to '1' indicating that we processed cpa req for
* one virtual address page and its pfn. TBD: numpages can be set based
* on the initial value and the level returned by lookup_address().
*/
if (within(vaddr, PAGE_OFFSET,
PAGE_OFFSET + (max_pfn_mapped << PAGE_SHIFT))) {
cpa->numpages = 1;
cpa->pfn = __pa(vaddr) >> PAGE_SHIFT;
return 0;
} else if (__cpa_pfn_in_highmap(cpa->pfn)) {
/* Faults in the highmap are OK, so do not warn: */
return -EFAULT;
} else {
WARN(1, KERN_WARNING "CPA: called for zero pte. "
"vaddr = %lx cpa->vaddr = %lx\n", vaddr,
*cpa->vaddr);
return -EFAULT;
}
}
static int __change_page_attr(struct cpa_data *cpa, int primary)
{
unsigned long address;
int do_split, err;
unsigned int level;
pte_t *kpte, old_pte;
address = __cpa_addr(cpa, cpa->curpage);
repeat:
kpte = _lookup_address_cpa(cpa, address, &level);
if (!kpte)
return __cpa_process_fault(cpa, address, primary);
old_pte = *kpte;
if (pte_none(old_pte))
return __cpa_process_fault(cpa, address, primary);
if (level == PG_LEVEL_4K) {
pte_t new_pte;
pgprot_t old_prot = pte_pgprot(old_pte);
pgprot_t new_prot = pte_pgprot(old_pte);
unsigned long pfn = pte_pfn(old_pte);
pgprot_val(new_prot) &= ~pgprot_val(cpa->mask_clr);
pgprot_val(new_prot) |= pgprot_val(cpa->mask_set);
cpa_inc_4k_install();
/* Hand in lpsize = 0 to enforce the protection mechanism */
new_prot = static_protections(new_prot, address, pfn, 1, 0,
CPA_PROTECT);
new_prot = verify_rwx(old_prot, new_prot, address, pfn, 1);
new_prot = pgprot_clear_protnone_bits(new_prot);
/*
* We need to keep the pfn from the existing PTE,
* after all we're only going to change it's attributes
* not the memory it points to
*/
new_pte = pfn_pte(pfn, new_prot);
cpa->pfn = pfn;
/*
* Do we really change anything ?
*/
if (pte_val(old_pte) != pte_val(new_pte)) {
set_pte_atomic(kpte, new_pte);
cpa->flags |= CPA_FLUSHTLB;
}
cpa->numpages = 1;
return 0;
}
/*
* Check, whether we can keep the large page intact
* and just change the pte:
*/
do_split = should_split_large_page(kpte, address, cpa);
/*
* When the range fits into the existing large page,
* return. cp->numpages and cpa->tlbflush have been updated in
* try_large_page:
*/
if (do_split <= 0)
return do_split;
/*
* We have to split the large page:
*/
err = split_large_page(cpa, kpte, address);
if (!err)
goto repeat;
return err;
}
static int __change_page_attr_set_clr(struct cpa_data *cpa, int primary);
/*
* Check the directmap and "high kernel map" 'aliases'.
*/
static int cpa_process_alias(struct cpa_data *cpa)
{
struct cpa_data alias_cpa;
unsigned long laddr = (unsigned long)__va(cpa->pfn << PAGE_SHIFT);
unsigned long vaddr;
int ret;
if (!pfn_range_is_mapped(cpa->pfn, cpa->pfn + 1))
return 0;
/*
* No need to redo, when the primary call touched the direct
* mapping already:
*/
vaddr = __cpa_addr(cpa, cpa->curpage);
if (!(within(vaddr, PAGE_OFFSET,
PAGE_OFFSET + (max_pfn_mapped << PAGE_SHIFT)))) {
alias_cpa = *cpa;
alias_cpa.vaddr = &laddr;
alias_cpa.flags &= ~(CPA_PAGES_ARRAY | CPA_ARRAY);
alias_cpa.curpage = 0;
/* Directmap always has NX set, do not modify. */
if (__supported_pte_mask & _PAGE_NX) {
alias_cpa.mask_clr.pgprot &= ~_PAGE_NX;
alias_cpa.mask_set.pgprot &= ~_PAGE_NX;
}
cpa->force_flush_all = 1;
ret = __change_page_attr_set_clr(&alias_cpa, 0);
if (ret)
return ret;
}
#ifdef CONFIG_X86_64
/*
* If the primary call didn't touch the high mapping already
* and the physical address is inside the kernel map, we need
* to touch the high mapped kernel as well:
*/
if (!within(vaddr, (unsigned long)_text, _brk_end) &&
__cpa_pfn_in_highmap(cpa->pfn)) {
unsigned long temp_cpa_vaddr = (cpa->pfn << PAGE_SHIFT) +
__START_KERNEL_map - phys_base;
alias_cpa = *cpa;
alias_cpa.vaddr = &temp_cpa_vaddr;
alias_cpa.flags &= ~(CPA_PAGES_ARRAY | CPA_ARRAY);
alias_cpa.curpage = 0;
/*
* [_text, _brk_end) also covers data, do not modify NX except
* in cases where the highmap is the primary target.
*/
if (__supported_pte_mask & _PAGE_NX) {
alias_cpa.mask_clr.pgprot &= ~_PAGE_NX;
alias_cpa.mask_set.pgprot &= ~_PAGE_NX;
}
cpa->force_flush_all = 1;
/*
* The high mapping range is imprecise, so ignore the
* return value.
*/
__change_page_attr_set_clr(&alias_cpa, 0);
}
#endif
return 0;
}
static int __change_page_attr_set_clr(struct cpa_data *cpa, int primary)
{
unsigned long numpages = cpa->numpages;
unsigned long rempages = numpages;
int ret = 0;
/*
* No changes, easy!
*/
if (!(pgprot_val(cpa->mask_set) | pgprot_val(cpa->mask_clr)) &&
!cpa->force_split)
return ret;
while (rempages) {
/*
* Store the remaining nr of pages for the large page
* preservation check.
*/
cpa->numpages = rempages;
/* for array changes, we can't use large page */
if (cpa->flags & (CPA_ARRAY | CPA_PAGES_ARRAY))
cpa->numpages = 1;
if (!debug_pagealloc_enabled())
spin_lock(&cpa_lock);
ret = __change_page_attr(cpa, primary);
if (!debug_pagealloc_enabled())
spin_unlock(&cpa_lock);
if (ret)
goto out;
if (primary && !(cpa->flags & CPA_NO_CHECK_ALIAS)) {
ret = cpa_process_alias(cpa);
if (ret)
goto out;
}
/*
* Adjust the number of pages with the result of the
* CPA operation. Either a large page has been
* preserved or a single page update happened.
*/
BUG_ON(cpa->numpages > rempages || !cpa->numpages);
rempages -= cpa->numpages;
cpa->curpage += cpa->numpages;
}
out:
/* Restore the original numpages */
cpa->numpages = numpages;
return ret;
}
static int change_page_attr_set_clr(unsigned long *addr, int numpages,
pgprot_t mask_set, pgprot_t mask_clr,
int force_split, int in_flag,
struct page **pages)
{
struct cpa_data cpa;
int ret, cache;
memset(&cpa, 0, sizeof(cpa));
/*
* Check, if we are requested to set a not supported
* feature. Clearing non-supported features is OK.
*/
mask_set = canon_pgprot(mask_set);
if (!pgprot_val(mask_set) && !pgprot_val(mask_clr) && !force_split)
return 0;
/* Ensure we are PAGE_SIZE aligned */
if (in_flag & CPA_ARRAY) {
int i;
for (i = 0; i < numpages; i++) {
if (addr[i] & ~PAGE_MASK) {
addr[i] &= PAGE_MASK;
WARN_ON_ONCE(1);
}
}
} else if (!(in_flag & CPA_PAGES_ARRAY)) {
/*
* in_flag of CPA_PAGES_ARRAY implies it is aligned.
* No need to check in that case
*/
if (*addr & ~PAGE_MASK) {
*addr &= PAGE_MASK;
/*
* People should not be passing in unaligned addresses:
*/
WARN_ON_ONCE(1);
}
}
/* Must avoid aliasing mappings in the highmem code */
kmap_flush_unused();
vm_unmap_aliases();
cpa.vaddr = addr;
cpa.pages = pages;
cpa.numpages = numpages;
cpa.mask_set = mask_set;
cpa.mask_clr = mask_clr;
cpa.flags = in_flag;
cpa.curpage = 0;
cpa.force_split = force_split;
ret = __change_page_attr_set_clr(&cpa, 1);
/*
* Check whether we really changed something:
*/
if (!(cpa.flags & CPA_FLUSHTLB))
goto out;
/*
* No need to flush, when we did not set any of the caching
* attributes:
*/
cache = !!pgprot2cachemode(mask_set);
/*
* On error; flush everything to be sure.
*/
if (ret) {
cpa_flush_all(cache);
goto out;
}
cpa_flush(&cpa, cache);
out:
return ret;
}
static inline int change_page_attr_set(unsigned long *addr, int numpages,
pgprot_t mask, int array)
{
return change_page_attr_set_clr(addr, numpages, mask, __pgprot(0), 0,
(array ? CPA_ARRAY : 0), NULL);
}
static inline int change_page_attr_clear(unsigned long *addr, int numpages,
pgprot_t mask, int array)
{
return change_page_attr_set_clr(addr, numpages, __pgprot(0), mask, 0,
(array ? CPA_ARRAY : 0), NULL);
}
static inline int cpa_set_pages_array(struct page **pages, int numpages,
pgprot_t mask)
{
return change_page_attr_set_clr(NULL, numpages, mask, __pgprot(0), 0,
CPA_PAGES_ARRAY, pages);
}
static inline int cpa_clear_pages_array(struct page **pages, int numpages,
pgprot_t mask)
{
return change_page_attr_set_clr(NULL, numpages, __pgprot(0), mask, 0,
CPA_PAGES_ARRAY, pages);
}
/*
* __set_memory_prot is an internal helper for callers that have been passed
* a pgprot_t value from upper layers and a reservation has already been taken.
* If you want to set the pgprot to a specific page protocol, use the
* set_memory_xx() functions.
*/
int __set_memory_prot(unsigned long addr, int numpages, pgprot_t prot)
{
return change_page_attr_set_clr(&addr, numpages, prot,
__pgprot(~pgprot_val(prot)), 0, 0,
NULL);
}
int _set_memory_uc(unsigned long addr, int numpages)
{
/*
* for now UC MINUS. see comments in ioremap()
* If you really need strong UC use ioremap_uc(), but note
* that you cannot override IO areas with set_memory_*() as
* these helpers cannot work with IO memory.
*/
return change_page_attr_set(&addr, numpages,
cachemode2pgprot(_PAGE_CACHE_MODE_UC_MINUS),
0);
}
int set_memory_uc(unsigned long addr, int numpages)
{
int ret;
/*
* for now UC MINUS. see comments in ioremap()
*/
ret = memtype_reserve(__pa(addr), __pa(addr) + numpages * PAGE_SIZE,
_PAGE_CACHE_MODE_UC_MINUS, NULL);
if (ret)
goto out_err;
ret = _set_memory_uc(addr, numpages);
if (ret)
goto out_free;
return 0;
out_free:
memtype_free(__pa(addr), __pa(addr) + numpages * PAGE_SIZE);
out_err:
return ret;
}
EXPORT_SYMBOL(set_memory_uc);
int _set_memory_wc(unsigned long addr, int numpages)
{
int ret;
ret = change_page_attr_set(&addr, numpages,
cachemode2pgprot(_PAGE_CACHE_MODE_UC_MINUS),
0);
if (!ret) {
ret = change_page_attr_set_clr(&addr, numpages,
cachemode2pgprot(_PAGE_CACHE_MODE_WC),
__pgprot(_PAGE_CACHE_MASK),
0, 0, NULL);
}
return ret;
}
int set_memory_wc(unsigned long addr, int numpages)
{
int ret;
ret = memtype_reserve(__pa(addr), __pa(addr) + numpages * PAGE_SIZE,
_PAGE_CACHE_MODE_WC, NULL);
if (ret)
return ret;
ret = _set_memory_wc(addr, numpages);
if (ret)
memtype_free(__pa(addr), __pa(addr) + numpages * PAGE_SIZE);
return ret;
}
EXPORT_SYMBOL(set_memory_wc);
int _set_memory_wt(unsigned long addr, int numpages)
{
return change_page_attr_set(&addr, numpages,
cachemode2pgprot(_PAGE_CACHE_MODE_WT), 0);
}
int _set_memory_wb(unsigned long addr, int numpages)
{
/* WB cache mode is hard wired to all cache attribute bits being 0 */
return change_page_attr_clear(&addr, numpages,
__pgprot(_PAGE_CACHE_MASK), 0);
}
int set_memory_wb(unsigned long addr, int numpages)
{
int ret;
ret = _set_memory_wb(addr, numpages);
if (ret)
return ret;
memtype_free(__pa(addr), __pa(addr) + numpages * PAGE_SIZE);
return 0;
}
EXPORT_SYMBOL(set_memory_wb);
/* Prevent speculative access to a page by marking it not-present */
#ifdef CONFIG_X86_64
int set_mce_nospec(unsigned long pfn)
{
unsigned long decoy_addr;
int rc;
/* SGX pages are not in the 1:1 map */
if (arch_is_platform_page(pfn << PAGE_SHIFT))
return 0;
/*
* We would like to just call:
* set_memory_XX((unsigned long)pfn_to_kaddr(pfn), 1);
* but doing that would radically increase the odds of a
* speculative access to the poison page because we'd have
* the virtual address of the kernel 1:1 mapping sitting
* around in registers.
* Instead we get tricky. We create a non-canonical address
* that looks just like the one we want, but has bit 63 flipped.
* This relies on set_memory_XX() properly sanitizing any __pa()
* results with __PHYSICAL_MASK or PTE_PFN_MASK.
*/
decoy_addr = (pfn << PAGE_SHIFT) + (PAGE_OFFSET ^ BIT(63));
rc = set_memory_np(decoy_addr, 1);
if (rc)
pr_warn("Could not invalidate pfn=0x%lx from 1:1 map\n", pfn);
return rc;
}
static int set_memory_p(unsigned long *addr, int numpages)
{
return change_page_attr_set(addr, numpages, __pgprot(_PAGE_PRESENT), 0);
}
/* Restore full speculative operation to the pfn. */
int clear_mce_nospec(unsigned long pfn)
{
unsigned long addr = (unsigned long) pfn_to_kaddr(pfn);
return set_memory_p(&addr, 1);
}
EXPORT_SYMBOL_GPL(clear_mce_nospec);
#endif /* CONFIG_X86_64 */
int set_memory_x(unsigned long addr, int numpages)
{
if (!(__supported_pte_mask & _PAGE_NX))
return 0;
return change_page_attr_clear(&addr, numpages, __pgprot(_PAGE_NX), 0);
}
int set_memory_nx(unsigned long addr, int numpages)
{
if (!(__supported_pte_mask & _PAGE_NX))
return 0;
return change_page_attr_set(&addr, numpages, __pgprot(_PAGE_NX), 0);
}
int set_memory_ro(unsigned long addr, int numpages)
{
return change_page_attr_clear(&addr, numpages, __pgprot(_PAGE_RW), 0);
}
int set_memory_rox(unsigned long addr, int numpages)
{
pgprot_t clr = __pgprot(_PAGE_RW);
if (__supported_pte_mask & _PAGE_NX)
clr.pgprot |= _PAGE_NX;
return change_page_attr_clear(&addr, numpages, clr, 0);
}
int set_memory_rw(unsigned long addr, int numpages)
{
return change_page_attr_set(&addr, numpages, __pgprot(_PAGE_RW), 0);
}
int set_memory_np(unsigned long addr, int numpages)
{
return change_page_attr_clear(&addr, numpages, __pgprot(_PAGE_PRESENT), 0);
}
int set_memory_np_noalias(unsigned long addr, int numpages)
{
return change_page_attr_set_clr(&addr, numpages, __pgprot(0),
__pgprot(_PAGE_PRESENT), 0,
CPA_NO_CHECK_ALIAS, NULL);
}
int set_memory_4k(unsigned long addr, int numpages)
{
return change_page_attr_set_clr(&addr, numpages, __pgprot(0),
__pgprot(0), 1, 0, NULL);
}
int set_memory_nonglobal(unsigned long addr, int numpages)
{
return change_page_attr_clear(&addr, numpages,
__pgprot(_PAGE_GLOBAL), 0);
}
int set_memory_global(unsigned long addr, int numpages)
{
return change_page_attr_set(&addr, numpages,
__pgprot(_PAGE_GLOBAL), 0);
}
/*
* __set_memory_enc_pgtable() is used for the hypervisors that get
* informed about "encryption" status via page tables.
*/
static int __set_memory_enc_pgtable(unsigned long addr, int numpages, bool enc)
{
pgprot_t empty = __pgprot(0);
struct cpa_data cpa;
int ret;
/* Should not be working on unaligned addresses */
if (WARN_ONCE(addr & ~PAGE_MASK, "misaligned address: %#lx\n", addr))
addr &= PAGE_MASK;
memset(&cpa, 0, sizeof(cpa));
cpa.vaddr = &addr;
cpa.numpages = numpages;
cpa.mask_set = enc ? pgprot_encrypted(empty) : pgprot_decrypted(empty);
cpa.mask_clr = enc ? pgprot_decrypted(empty) : pgprot_encrypted(empty);
cpa.pgd = init_mm.pgd;
/* Must avoid aliasing mappings in the highmem code */
kmap_flush_unused();
vm_unmap_aliases();
/* Flush the caches as needed before changing the encryption attribute. */
if (x86_platform.guest.enc_tlb_flush_required(enc))
cpa_flush(&cpa, x86_platform.guest.enc_cache_flush_required());
/* Notify hypervisor that we are about to set/clr encryption attribute. */
x86_platform.guest.enc_status_change_prepare(addr, numpages, enc);
ret = __change_page_attr_set_clr(&cpa, 1);
/*
* After changing the encryption attribute, we need to flush TLBs again
* in case any speculative TLB caching occurred (but no need to flush
* caches again). We could just use cpa_flush_all(), but in case TLB
* flushing gets optimized in the cpa_flush() path use the same logic
* as above.
*/
cpa_flush(&cpa, 0);
/* Notify hypervisor that we have successfully set/clr encryption attribute. */
if (!ret) {
if (!x86_platform.guest.enc_status_change_finish(addr, numpages, enc))
ret = -EIO;
}
return ret;
}
static int __set_memory_enc_dec(unsigned long addr, int numpages, bool enc)
{
if (hv_is_isolation_supported())
return hv_set_mem_host_visibility(addr, numpages, !enc);
if (cc_platform_has(CC_ATTR_MEM_ENCRYPT))
return __set_memory_enc_pgtable(addr, numpages, enc);
return 0;
}
int set_memory_encrypted(unsigned long addr, int numpages)
{
return __set_memory_enc_dec(addr, numpages, true);
}
EXPORT_SYMBOL_GPL(set_memory_encrypted);
int set_memory_decrypted(unsigned long addr, int numpages)
{
return __set_memory_enc_dec(addr, numpages, false);
}
EXPORT_SYMBOL_GPL(set_memory_decrypted);
int set_pages_uc(struct page *page, int numpages)
{
unsigned long addr = (unsigned long)page_address(page);
return set_memory_uc(addr, numpages);
}
EXPORT_SYMBOL(set_pages_uc);
static int _set_pages_array(struct page **pages, int numpages,
enum page_cache_mode new_type)
{
unsigned long start;
unsigned long end;
enum page_cache_mode set_type;
int i;
int free_idx;
int ret;
for (i = 0; i < numpages; i++) {
if (PageHighMem(pages[i]))
continue;
start = page_to_pfn(pages[i]) << PAGE_SHIFT;
end = start + PAGE_SIZE;
if (memtype_reserve(start, end, new_type, NULL))
goto err_out;
}
/* If WC, set to UC- first and then WC */
set_type = (new_type == _PAGE_CACHE_MODE_WC) ?
_PAGE_CACHE_MODE_UC_MINUS : new_type;
ret = cpa_set_pages_array(pages, numpages,
cachemode2pgprot(set_type));
if (!ret && new_type == _PAGE_CACHE_MODE_WC)
ret = change_page_attr_set_clr(NULL, numpages,
cachemode2pgprot(
_PAGE_CACHE_MODE_WC),
__pgprot(_PAGE_CACHE_MASK),
0, CPA_PAGES_ARRAY, pages);
if (ret)
goto err_out;
return 0; /* Success */
err_out:
free_idx = i;
for (i = 0; i < free_idx; i++) {
if (PageHighMem(pages[i]))
continue;
start = page_to_pfn(pages[i]) << PAGE_SHIFT;
end = start + PAGE_SIZE;
memtype_free(start, end);
}
return -EINVAL;
}
int set_pages_array_uc(struct page **pages, int numpages)
{
return _set_pages_array(pages, numpages, _PAGE_CACHE_MODE_UC_MINUS);
}
EXPORT_SYMBOL(set_pages_array_uc);
int set_pages_array_wc(struct page **pages, int numpages)
{
return _set_pages_array(pages, numpages, _PAGE_CACHE_MODE_WC);
}
EXPORT_SYMBOL(set_pages_array_wc);
int set_pages_wb(struct page *page, int numpages)
{
unsigned long addr = (unsigned long)page_address(page);
return set_memory_wb(addr, numpages);
}
EXPORT_SYMBOL(set_pages_wb);
int set_pages_array_wb(struct page **pages, int numpages)
{
int retval;
unsigned long start;
unsigned long end;
int i;
/* WB cache mode is hard wired to all cache attribute bits being 0 */
retval = cpa_clear_pages_array(pages, numpages,
__pgprot(_PAGE_CACHE_MASK));
if (retval)
return retval;
for (i = 0; i < numpages; i++) {
if (PageHighMem(pages[i]))
continue;
start = page_to_pfn(pages[i]) << PAGE_SHIFT;
end = start + PAGE_SIZE;
memtype_free(start, end);
}
return 0;
}
EXPORT_SYMBOL(set_pages_array_wb);
int set_pages_ro(struct page *page, int numpages)
{
unsigned long addr = (unsigned long)page_address(page);
return set_memory_ro(addr, numpages);
}
int set_pages_rw(struct page *page, int numpages)
{
unsigned long addr = (unsigned long)page_address(page);
return set_memory_rw(addr, numpages);
}
static int __set_pages_p(struct page *page, int numpages)
{
unsigned long tempaddr = (unsigned long) page_address(page);
struct cpa_data cpa = { .vaddr = &tempaddr,
.pgd = NULL,
.numpages = numpages,
.mask_set = __pgprot(_PAGE_PRESENT | _PAGE_RW),
.mask_clr = __pgprot(0),
.flags = CPA_NO_CHECK_ALIAS };
/*
* No alias checking needed for setting present flag. otherwise,
* we may need to break large pages for 64-bit kernel text
* mappings (this adds to complexity if we want to do this from
* atomic context especially). Let's keep it simple!
*/
return __change_page_attr_set_clr(&cpa, 1);
}
static int __set_pages_np(struct page *page, int numpages)
{
unsigned long tempaddr = (unsigned long) page_address(page);
struct cpa_data cpa = { .vaddr = &tempaddr,
.pgd = NULL,
.numpages = numpages,
.mask_set = __pgprot(0),
.mask_clr = __pgprot(_PAGE_PRESENT | _PAGE_RW),
.flags = CPA_NO_CHECK_ALIAS };
/*
* No alias checking needed for setting not present flag. otherwise,
* we may need to break large pages for 64-bit kernel text
* mappings (this adds to complexity if we want to do this from
* atomic context especially). Let's keep it simple!
*/
return __change_page_attr_set_clr(&cpa, 1);
}
int set_direct_map_invalid_noflush(struct page *page)
{
return __set_pages_np(page, 1);
}
int set_direct_map_default_noflush(struct page *page)
{
return __set_pages_p(page, 1);
}
#ifdef CONFIG_DEBUG_PAGEALLOC
void __kernel_map_pages(struct page *page, int numpages, int enable)
{
if (PageHighMem(page))
return;
if (!enable) {
debug_check_no_locks_freed(page_address(page),
numpages * PAGE_SIZE);
}
/*
* The return value is ignored as the calls cannot fail.
* Large pages for identity mappings are not used at boot time
* and hence no memory allocations during large page split.
*/
if (enable)
__set_pages_p(page, numpages);
else
__set_pages_np(page, numpages);
/*
* We should perform an IPI and flush all tlbs,
* but that can deadlock->flush only current cpu.
* Preemption needs to be disabled around __flush_tlb_all() due to
* CR3 reload in __native_flush_tlb().
*/
preempt_disable();
__flush_tlb_all();
preempt_enable();
arch_flush_lazy_mmu_mode();
}
#endif /* CONFIG_DEBUG_PAGEALLOC */
bool kernel_page_present(struct page *page)
{
unsigned int level;
pte_t *pte;
if (PageHighMem(page))
return false;
pte = lookup_address((unsigned long)page_address(page), &level);
return (pte_val(*pte) & _PAGE_PRESENT);
}
int __init kernel_map_pages_in_pgd(pgd_t *pgd, u64 pfn, unsigned long address,
unsigned numpages, unsigned long page_flags)
{
int retval = -EINVAL;
struct cpa_data cpa = {
.vaddr = &address,
.pfn = pfn,
.pgd = pgd,
.numpages = numpages,
.mask_set = __pgprot(0),
.mask_clr = __pgprot(~page_flags & (_PAGE_NX|_PAGE_RW)),
.flags = CPA_NO_CHECK_ALIAS,
};
WARN_ONCE(num_online_cpus() > 1, "Don't call after initializing SMP");
if (!(__supported_pte_mask & _PAGE_NX))
goto out;
if (!(page_flags & _PAGE_ENC))
cpa.mask_clr = pgprot_encrypted(cpa.mask_clr);
cpa.mask_set = __pgprot(_PAGE_PRESENT | page_flags);
retval = __change_page_attr_set_clr(&cpa, 1);
__flush_tlb_all();
out:
return retval;
}
/*
* __flush_tlb_all() flushes mappings only on current CPU and hence this
* function shouldn't be used in an SMP environment. Presently, it's used only
* during boot (way before smp_init()) by EFI subsystem and hence is ok.
*/
int __init kernel_unmap_pages_in_pgd(pgd_t *pgd, unsigned long address,
unsigned long numpages)
{
int retval;
/*
* The typical sequence for unmapping is to find a pte through
* lookup_address_in_pgd() (ideally, it should never return NULL because
* the address is already mapped) and change it's protections. As pfn is
* the *target* of a mapping, it's not useful while unmapping.
*/
struct cpa_data cpa = {
.vaddr = &address,
.pfn = 0,
.pgd = pgd,
.numpages = numpages,
.mask_set = __pgprot(0),
.mask_clr = __pgprot(_PAGE_PRESENT | _PAGE_RW),
.flags = CPA_NO_CHECK_ALIAS,
};
WARN_ONCE(num_online_cpus() > 1, "Don't call after initializing SMP");
retval = __change_page_attr_set_clr(&cpa, 1);
__flush_tlb_all();
return retval;
}
/*
* The testcases use internal knowledge of the implementation that shouldn't
* be exposed to the rest of the kernel. Include these directly here.
*/
#ifdef CONFIG_CPA_DEBUG
#include "cpa-test.c"
#endif