diff options
| -rw-r--r-- | sys/include/vm/vm.h | 15 | ||||
| -rw-r--r-- | sys/include/vm/vm_physseg.h | 4 | ||||
| -rw-r--r-- | sys/vm/vm_physseg.c | 92 |
3 files changed, 107 insertions, 4 deletions
diff --git a/sys/include/vm/vm.h b/sys/include/vm/vm.h index 78038f0..baf7677 100644 --- a/sys/include/vm/vm.h +++ b/sys/include/vm/vm.h @@ -32,6 +32,8 @@ #include <sys/types.h> #include <sys/limine.h> +#include <sys/cdefs.h> +#include <vm/vm_page.h> extern volatile struct limine_hhdm_request g_hhdm_request; @@ -40,6 +42,19 @@ extern volatile struct limine_hhdm_request g_hhdm_request; #define PHYS_TO_VIRT(phys) (void *)((uintptr_t)phys + VM_HIGHER_HALF) #define VIRT_TO_PHYS(virt) ((uintptr_t)virt - VM_HIGHER_HALF) +/* + * Returns the machine's pagesize: + * + * XXX TODO: This needs to be moved to vmm_init.c + * while returning a non-constant value. + */ +static inline size_t +vm_get_page_size(void) +{ + return 4096; +} + void vm_init(void); +struct vas vm_new_vas(void); #endif /* !_VM_H_ */ diff --git a/sys/include/vm/vm_physseg.h b/sys/include/vm/vm_physseg.h index 5bf21db..5865a84 100644 --- a/sys/include/vm/vm_physseg.h +++ b/sys/include/vm/vm_physseg.h @@ -30,6 +30,10 @@ #ifndef _VM_VM_PHYSSEG_H_ #define _VM_VM_PHYSSEG_H_ +#include <sys/types.h> + void vm_physseg_init(void); +uintptr_t vm_alloc_pageframe(size_t count); +void vm_free_pageframe(uintptr_t base, size_t count); #endif /* !_VM_VM_PHYSSEG_H_ */ diff --git a/sys/vm/vm_physseg.c b/sys/vm/vm_physseg.c index f21c282..12f6844 100644 --- a/sys/vm/vm_physseg.c +++ b/sys/vm/vm_physseg.c @@ -67,13 +67,16 @@ static const int MAX_SEGMENTS = __ARRAY_COUNT(segment_name); static bitmap_t bitmap = NULL; +static size_t last_used_idx = 0; static size_t bitmap_size = 0; +static size_t highest_frame_idx; static size_t bitmap_free_start; /* Beginning bit of free region */ static void vm_physseg_bitmap_alloc(void) { struct limine_memmap_entry *entry; + uintptr_t highest_addr = 0; for (size_t i = 0; i < resp->entry_count; ++i) { entry = resp->entries[i]; @@ -95,6 +98,8 @@ vm_physseg_bitmap_alloc(void) entry->base += bitmap_size; return; } + + highest_addr = __MAX(highest_addr, entry->base + entry->length); } } @@ -142,11 +147,10 @@ static void vm_physseg_bitmap_init(void) { uintptr_t highest_addr; - size_t highest_page_idx; struct limine_memmap_entry *entry; highest_addr = 0; - highest_page_idx = 0; + highest_frame_idx = 0; /* Find the highest entry */ for (size_t i = 0; i < resp->entry_count; ++i) { @@ -160,8 +164,8 @@ vm_physseg_bitmap_init(void) highest_addr = __MAX(highest_addr, entry->base + entry->length); } - highest_page_idx = highest_addr / 0x1000; - bitmap_size = __ALIGN_UP(highest_page_idx / 8, 0x1000); + highest_frame_idx = highest_addr / 0x1000; + bitmap_size = __ALIGN_UP(highest_frame_idx / 8, 0x1000); DPRINTF("Bitmap size: %d bytes\n", bitmap_size); DPRINTF("Allocating and populating bitmap now...\n"); @@ -170,6 +174,86 @@ vm_physseg_bitmap_init(void) vm_physseg_bitmap_populate(); } +static uintptr_t +vm_alloc_pageframe_internal(size_t count) +{ + bool can_alloc = false; + + bool is_free; /* True if we found a free frame */ + size_t free_count = 0; /* How many we found that are free? */ + uintptr_t frame_idx = 0; /* The base index of first free frame */ + + for (size_t i = last_used_idx; i < bitmap_size*8; ++i) { + is_free = !bitmap_test_bit(bitmap, i); + + if (!is_free) { + free_count = 0; + continue; + } + + if (free_count == count) { + can_alloc = true; + break; + } + + /* Assume free here */ + if (frame_idx == 0) + frame_idx = i; + + ++free_count; + } + + if (!can_alloc) { + /* No free memory! */ + last_used_idx = 0; + return 0; + } + + /* Mark the memory as allocated */ + for (size_t i = frame_idx; i < frame_idx+count; ++i) { + bitmap_set_bit(bitmap, i); + } + + /* Return the physical address */ + last_used_idx = frame_idx; + return frame_idx*vm_get_page_size(); +} + +/* + * Allocates physical pageframes. + * + * @count: Number of pageframes to allocate. + */ +uintptr_t +vm_alloc_pageframe(size_t count) +{ + uintptr_t phys; + + phys = vm_alloc_pageframe_internal(count); + + if (phys == 0) + return 0; + + vm_zero_page(PHYS_TO_VIRT(phys), count); + return phys; +} + +/* + * Frees physical pageframes. + * + * @base: Base to start freeing at. + * @count: Number of pageframes to free. + */ +void +vm_free_pageframe(uintptr_t base, size_t count) +{ + const size_t PAGE_SIZE = vm_get_page_size(); + + for (uintptr_t p = base; p < base + (count*PAGE_SIZE); p += PAGE_SIZE) { + bitmap_unset_bit(bitmap, p/0x1000); + } +} + void vm_physseg_init(void) { |