diff options
Diffstat (limited to 'kernel/memory/paging.c')
| -rw-r--r-- | kernel/memory/paging.c | 36 |
1 files changed, 28 insertions, 8 deletions
diff --git a/kernel/memory/paging.c b/kernel/memory/paging.c index 58c5091..24a9ea7 100644 --- a/kernel/memory/paging.c +++ b/kernel/memory/paging.c @@ -796,16 +796,36 @@ void *mem_alloc_pages(mem_ctx_t ctx, size_t count, unsigned int flags) void *mem_alloc_pages_at(mem_ctx_t ctx, size_t count, void *virt, unsigned int flags) { - void *phys = alloc_phys_pages(count); - if (phys == NULL) - return NULL; + size_t pages_needed = count; + uint8_t *virtual_address = virt; - if (map_pages((volatile struct pml4 *)ctx->pml4, virt, phys, flags, - count)) { - if (phys) - free_phys_pages(phys, count); - return NULL; + void *phys_start = NULL; + + while (pages_needed > 0) { + struct phys_page_slice phys_pages = + alloc_phys_page_withextra(pages_needed); + if (phys_pages.pagestart == NULL) { + free_phys_pages(phys_start ? phys_start : phys_pages.pagestart, + count - pages_needed); + return NULL; + } + + if (!phys_start) + phys_start = phys_pages.pagestart; + + assert(pages_needed >= phys_pages.num_pages, "overflow"); + pages_needed -= phys_pages.num_pages; + virtual_address += phys_pages.num_pages * PAGE_SIZE; + + if (map_pages((volatile struct pml4 *)ctx->pml4, + (void *)virtual_address, phys_pages.pagestart, flags, + phys_pages.num_pages)) { + assert(phys_start, "expected something allocated"); + free_phys_pages(phys_start, count - pages_needed); + return NULL; + } } + return virt; } |