diff options
Diffstat (limited to 'kernel/memory.c')
| -rw-r--r-- | kernel/memory.c | 149 |
1 files changed, 143 insertions, 6 deletions
diff --git a/kernel/memory.c b/kernel/memory.c index fee6821..ebcf6b8 100644 --- a/kernel/memory.c +++ b/kernel/memory.c @@ -1,6 +1,8 @@ #include "memory.h" #include "kprint.h" +#include "panic.h" +#include <kernel/entry.h> #include <kernel/memory/paging.h> /* kernel virtual space guarantees @@ -16,6 +18,28 @@ #define align_next(v, a) (((uint64_t)v + a - 1) & ~(a - 1)) +// a conservative 128MB for kernel heap +#define KERNEL_HEAP_SPACE_SIZE (128 << 20) + +typedef int (*page_fault_handler_func)(uint32_t code, void *address); + +enum memory_space_flags +{ + AVAILABLE_MEMORY_SPACE, // memory that is not used + SYSTEM_MEMORY_SPACE, // memory that cannot fault + ANONYMOUS_MEMORY_SPACE, // memory that can fault +}; + +struct memory_space +{ + enum memory_space_flags flags; + page_fault_handler_func handler; + void *base; + void *head; + struct memory_space *next; + struct memory_space *prev; +}; + struct page { uint32_t next: 31; @@ -31,6 +55,7 @@ extern char k_data_end; static struct page *const page_array = (struct page *)0xffffffd800000000; static int first_free_page_index = -1; static size_t page_array_entries = 0; +static size_t free_pages = 0; // the temporary mapping place. never use this permanently. static void *const temp = (void *)0xffffffffffa00000; @@ -39,6 +64,24 @@ static uint64_t *const kernel_pm2 = (uint64_t *)0xffffffffffffe000; static uint64_t *get_kernel_pm1e(void *vaddr); static uint64_t *get_kernel_pm2e(void *vaddr); +static void *get_virtual_page(enum map_page_flags flags); +static void *kernel_map_page_at(void *vaddr, + phys_addr_t paddr, + enum map_page_flags flags); + +// handlers for memory space types +int anonymous_page_handler(uint32_t code, void *address); + +// the system memory_space's that are always present +static struct memory_space kernel_image_space; +static struct memory_space kernel_stack_space; +static struct memory_space kernel_pagemap_space; + +// NULL if the system address spaces are not set up +static struct memory_space *root_memory_space; + +// the kernel's own heap space +static struct memory_space kernel_heap_space; static struct memory_range init_grab_pages(struct memory_range *ranges, int count, @@ -232,14 +275,61 @@ static void init_create_page_array(struct memory_range *ranges, int count) init_populate_page_array(&pm2_pages, 1); } +static struct memory_space init_system_space(void *base, void *head) +{ + struct memory_space space = {SYSTEM_MEMORY_SPACE, NULL, base, head, NULL, NULL}; + return space; +} + +static struct memory_space init_anonymous_space(void *base, void *head) +{ + struct memory_space space = {ANONYMOUS_MEMORY_SPACE, + &anonymous_page_handler, + base, + head, + NULL, + NULL}; + + return space; +} + +static void init_heap_space(struct memory_space *heap) +{ + uint64_t *heap_alias = heap->base; + *heap_alias = 0xfafafafa; +} + void memory_init(struct memory_range *ranges, int count) { init_create_page_array(ranges, count); + // initialize always-present memory spaces for the vmm + kernel_image_space = init_system_space((void *)&k_text_begin, + (void *)align_next(&k_data_end, PAGE_SIZE)); + kernel_stack_space = init_system_space((void *)KERNEL_ENTRY_STACK_BASE, + (void *)KERNEL_ENTRY_STACK_HEAD); + kernel_pagemap_space = init_system_space(kernel_pm1, (void *)-1LL); + + // initialize the kernel heap space + kernel_heap_space = init_anonymous_space(kernel_image_space.head, + (char *)kernel_image_space.head + + KERNEL_HEAP_SPACE_SIZE); + + // set up the list links + kernel_image_space.next = &kernel_heap_space; + kernel_heap_space.prev = &kernel_image_space; + kernel_heap_space.next = &kernel_stack_space; + kernel_stack_space.prev = &kernel_heap_space; + kernel_stack_space.next = &kernel_pagemap_space; + kernel_pagemap_space.prev = &kernel_stack_space; + + root_memory_space = &kernel_image_space; + + init_heap_space(&kernel_heap_space); } -void *kernel_map_page_at(void *vaddr, - phys_addr_t paddr, - enum map_page_flags flags) +static void *kernel_map_page_at(void *vaddr, + phys_addr_t paddr, + enum map_page_flags flags) { uint64_t entry = PAGE_PR; @@ -284,6 +374,11 @@ void *kernel_map_page_at(void *vaddr, return NULL; } +void *kernel_map_page(phys_addr_t paddr, enum map_page_flags flags) +{ + return kernel_map_page_at(get_virtual_page(flags), paddr, flags); +} + void kernel_unmap_page(void *vaddr) { uint64_t *pte = get_kernel_pm2e(vaddr); @@ -308,14 +403,15 @@ phys_addr_t page_alloc(void) { page_array[index].used = 1; first_free_page_index = page_array[index].next; + free_pages--; } return (phys_addr_t)index * PAGE_SIZE; } -void page_free(phys_addr_t page) +void page_free(phys_addr_t paddr) { - int index = page / PAGE_SIZE; + int index = paddr / PAGE_SIZE; if ((size_t)index > page_array_entries) { @@ -325,6 +421,7 @@ void page_free(phys_addr_t page) page_array[index].used = 0; page_array[index].next = first_free_page_index; first_free_page_index = index; + free_pages++; } static uint64_t *get_kernel_pm1e(void *vaddr) @@ -337,10 +434,50 @@ static uint64_t *get_kernel_pm2e(void *vaddr) return &kernel_pm2[kpm2_index(vaddr)]; } -int page_fault_handler(uint32_t code, void *address) +static void *get_virtual_page(enum map_page_flags flags) +{ + (void)flags; + return NULL; +} + +static struct memory_space *get_memory_space(void *address) +{ + // walk the memory space list + struct memory_space *space = root_memory_space; + + while (space) + { + if (space->base >= address && address <= space->head) + { + return space; + } + space = space->next; + } + + return NULL; +} + +int anonymous_page_handler(uint32_t code, void *address) { (void)code; (void)address; + kputs("anonymous fault\n"); + return -1; +} + +int page_fault_handler(uint32_t code, void *address) +{ kputs("page faulmt\n"); + struct memory_space *space = get_memory_space(address); + if (space && space->handler) + { + int result = space->handler(code, address); + + if (result) + { + panic(UNHANDLED_FAULT); + } + } + return 0; } |