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Improve dump_pagetables() functionality #314

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Nov 7, 2023
Merged

Improve dump_pagetables() functionality #314

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d538642
arch,pt: export vmap_lock to entire file context
wipawel Oct 31, 2023
3039230
arch,pt: improve dump_pagetables() functionality
wipawel Oct 31, 2023
77b04f0
arch,pt: add dump_pagetable_va() functions
wipawel Oct 31, 2023
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161 changes: 121 additions & 40 deletions arch/x86/pagetables.c
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Original file line number Diff line number Diff line change
Expand Up @@ -37,6 +37,16 @@ static pgentry_t *_tmp_mapping_entry;
cr3_t __aligned(PAGE_SIZE) cr3;
cr3_t user_cr3;

/* Used by lower level vmap() functions - must not be taken before mmap_lock */
static spinlock_t vmap_lock = SPINLOCK_INIT;

static inline void *tmp_map_mfn(mfn_t mfn) {
BUG_ON(mfn_invalid(mfn));
set_pgentry(_tmp_mapping_entry, mfn, L1_PROT);
invlpg(_tmp_mapping);
return _tmp_mapping;
}

static inline const char *dump_pte_flags(char *buf, size_t size, pte_t pte) {
/* clang-format off */
snprintf(buf, size, "%c %c%c%c%c%c%c%c%c%c",
Expand All @@ -55,60 +65,130 @@ static inline const char *dump_pte_flags(char *buf, size_t size, pte_t pte) {
return buf;
}

static inline void dump_page_table(void *table, int level) {
char flags[16];
int entries;
pte_t *pt = table;

static inline int level_to_entries(int level) {
switch (level) {
case 4:
entries = L4_PT_ENTRIES;
break;
return L4_PT_ENTRIES;
case 3:
entries = L3_PT_ENTRIES;
break;
return L3_PT_ENTRIES;
case 2:
entries = L2_PT_ENTRIES;
break;
return L2_PT_ENTRIES;
case 1:
entries = L1_PT_ENTRIES;
break;
return L1_PT_ENTRIES;
default:
return;
};
return 0;
}
}

for (int i = 0; i < entries; i++) {
static inline void dump_pte(void *entry, mfn_t table, int level, int index) {
pte_t *pte = entry;
paddr_t pt_paddr = mfn_to_paddr(table) + index * sizeof(pgentry_t);
paddr_t paddr = mfn_to_paddr(pte->mfn);
int indent = (4 - level) * 2;
char flags[16];

dump_pte_flags(flags, sizeof(flags), *pte);
printk("[0x%lx] %*s%d[%03u] paddr: 0x%016lx flags: %s\n", pt_paddr, indent, "L",
level, index, paddr, flags);
}

static void dump_pagetable(mfn_t table, int level) {
pte_t *pt;

BUG_ON(mfn_invalid(table));
pt = tmp_map_mfn(table);
BUG_ON(!pt);

for (int i = 0; i < level_to_entries(level); i++) {
if (!pt[i].P)
continue;

dump_pte_flags(flags, sizeof(flags), pt[i]);
paddr_t paddr = mfn_to_paddr(pt[i].mfn);
printk("[%p] %*s%d[%03u] paddr: 0x%016lx flags: %s\n", _ptr(virt_to_paddr(pt)),
(4 - level) * 2, "L", level, i, paddr, flags);
dump_pte(&pt[i], table, level, i);

if (level == 2 && ((pde_t *) pt)[i].PS)
continue;
if (level == 3 && ((pdpe_t *) pt)[i].PS)
continue;
dump_page_table(paddr_to_virt_kern(paddr), level - 1);
dump_pagetable(pt[i].mfn, level - 1);
pt = tmp_map_mfn(table);
}
}

void dump_pagetables(cr3_t *cr3_ptr) {
#if defined(__x86_64__)
int level = 4;
#else
int level = 3;
#endif
ASSERT(cr3_ptr);
if (mfn_invalid(cr3_ptr->mfn)) {
warning("CR3: 0x%lx is invalid", cr3.paddr);
return;
}

printk("Page Tables: CR3 paddr: 0x%lx\n", cr3.paddr);
spin_lock(&vmap_lock);
dump_pagetable(cr3_ptr->mfn, level);
spin_unlock(&vmap_lock);
}

void dump_pagetables(cr3_t cr3) {
printk("\nPage Tables:\n");
static void dump_pagetable_va(cr3_t *cr3_ptr, void *va) {
paddr_t tab_paddr;
pgentry_t *tab;
#if defined(__x86_64__)
int level = 4;
#else
int level = 3;
#endif

ASSERT(cr3_ptr);
if (mfn_invalid(cr3_ptr->mfn)) {
warning("CR3: 0x%lx is invalid", cr3.paddr);
return;
}

spin_lock(&vmap_lock);

tab = tmp_map_mfn(cr3_ptr->mfn);
#if defined(__x86_64__)
pml4_t *l4e = l4_table_entry((pml4_t *) tab, va);
dump_pte(l4e, cr3_ptr->mfn, level--, l4_table_index(va));

if (mfn_invalid(l4e->mfn))
goto unlock;

tab_paddr = mfn_to_paddr(l4e->mfn);
tab = tmp_map_mfn(l4e->mfn);
#endif
pdpe_t *l3e = l3_table_entry((pdpe_t *) tab, va);
dump_pte(l3e, tab_paddr, level--, l3_table_index(va));

if (mfn_invalid(l3e->mfn) || l3e->PS)
goto unlock;

tab_paddr = mfn_to_paddr(l3e->mfn);
tab = tmp_map_mfn(l3e->mfn);
pde_t *l2e = l2_table_entry((pde_t *) tab, va);
dump_pte(l2e, tab_paddr, level--, l2_table_index(va));

/* Map all used frames to be able to parse page tables */
map_used_memory();
if (mfn_invalid(l2e->mfn) || l2e->PS)
goto unlock;

printk("CR3: paddr: 0x%lx\n", cr3.paddr);
dump_page_table(paddr_to_virt_kern(cr3.paddr), 4);
tab_paddr = mfn_to_paddr(l2e->mfn);
tab = tmp_map_mfn(l2e->mfn);
pte_t *l1e = l1_table_entry((pte_t *) tab, va);
dump_pte(l1e, tab_paddr, level--, l1_table_index(va));

unlock:
spin_unlock(&vmap_lock);
}

static inline void *tmp_map_mfn(mfn_t mfn) {
BUG_ON(mfn_invalid(mfn));
set_pgentry(_tmp_mapping_entry, mfn, L1_PROT);
invlpg(_tmp_mapping);
return _tmp_mapping;
void dump_kern_pagetable_va(void *va) {
dump_pagetable_va(&cr3, va);
}

void dump_user_pagetable_va(void *va) {
dump_pagetable_va(&user_cr3, va);
}

static mfn_t get_cr3_mfn(cr3_t *cr3_entry) {
Expand Down Expand Up @@ -179,16 +259,13 @@ static void *_vmap(cr3_t *cr3_ptr, void *va, mfn_t mfn, unsigned int order,
#endif
unsigned long l3_flags, unsigned long l2_flags,
unsigned long l1_flags) {
static spinlock_t lock = SPINLOCK_INIT;
mfn_t l1t_mfn, l2t_mfn, l3t_mfn;
pgentry_t *tab, *entry;

if (!va || (_ul(va) & ~PAGE_ORDER_TO_MASK(order)))
return NULL;

dprintk("%s: va: %p mfn: 0x%lx (order: %u)\n", __func__, va, mfn, order);

spin_lock(&lock);
dprintk("%s: va: 0x%p mfn: 0x%lx (order: %u)\n", __func__, va, mfn, order);

#if defined(__x86_64__)
l3t_mfn = get_pgentry_mfn(get_cr3_mfn(cr3_ptr), l4_table_index(va), l4_flags);
Expand Down Expand Up @@ -222,7 +299,6 @@ static void *_vmap(cr3_t *cr3_ptr, void *va, mfn_t mfn, unsigned int order,
invlpg(va);

done:
spin_unlock(&lock);
return va;
}

Expand All @@ -233,7 +309,10 @@ void *vmap_kern(void *va, mfn_t mfn, unsigned int order,
unsigned long l3_flags, unsigned long l2_flags, unsigned long l1_flags) {
unsigned long _va = _ul(va) & PAGE_ORDER_TO_MASK(order);

return _vmap(&cr3, _ptr(_va), mfn, order, l4_flags, l3_flags, l2_flags, l1_flags);
spin_lock(&vmap_lock);
va = _vmap(&cr3, _ptr(_va), mfn, order, l4_flags, l3_flags, l2_flags, l1_flags);
spin_unlock(&vmap_lock);
return va;
}

void *vmap_user(void *va, mfn_t mfn, unsigned int order,
Expand All @@ -243,8 +322,10 @@ void *vmap_user(void *va, mfn_t mfn, unsigned int order,
unsigned long l3_flags, unsigned long l2_flags, unsigned long l1_flags) {
unsigned long _va = _ul(va) & PAGE_ORDER_TO_MASK(order);

return _vmap(&user_cr3, _ptr(_va), mfn, order, l4_flags, l3_flags, l2_flags,
l1_flags);
spin_lock(&vmap_lock);
va = _vmap(&user_cr3, _ptr(_va), mfn, order, l4_flags, l3_flags, l2_flags, l1_flags);
spin_unlock(&vmap_lock);
return va;
}

static inline void init_tmp_mapping(void) {
Expand Down
2 changes: 1 addition & 1 deletion common/setup.c
View file
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Original file line number Diff line number Diff line change
Expand Up @@ -227,7 +227,7 @@ void __noreturn __text_init kernel_start(uint32_t multiboot_magic, unsigned long
WRITE_SP(get_free_pages_top(PAGE_ORDER_2M, GFP_KERNEL_MAP));

if (opt_debug)
dump_pagetables(cr3);
dump_pagetables(&cr3);

map_bios_area();

Expand Down
4 changes: 3 additions & 1 deletion include/arch/x86/pagetable.h
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Original file line number Diff line number Diff line change
Expand Up @@ -287,7 +287,9 @@ extern pml4_t l4_pt_entries[L4_PT_ENTRIES];
#endif

extern void init_pagetables(void);
extern void dump_pagetables(cr3_t cr3);
extern void dump_pagetables(cr3_t *cr3_ptr);
extern void dump_kern_pagetable_va(void *va);
extern void dump_user_pagetable_va(void *va);

#endif /* __ASSEMBLY__ */

Expand Down
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