diff --git a/src/kernel/memory/vmm.c b/src/kernel/memory/vmm.c index 707fe41..e0bd1c3 100644 --- a/src/kernel/memory/vmm.c +++ b/src/kernel/memory/vmm.c @@ -52,14 +52,22 @@ int vmm_set_page(void *P4, uintptr_t addr, uintptr_t page, uint16_t flags) int touch_page(void *P4, uintptr_t addr, uint16_t flags) { - (void)flags; if(!P4) return -1; - if(!P4e(P4, addr).present) - P4e(P4, addr).value = pmm_alloc() | flags | PAGE_PRESENT; - if(!P3e(P4, addr).present) - P3e(P4, addr).value = pmm_alloc() | flags | PAGE_PRESENT; - if(!P2e(P4, addr).present) - P2e(P4, addr).value = pmm_alloc() | flags | PAGE_PRESENT; + + if((!P4e(P4, addr).present) + && (!(P4e(P4, addr).value = pmm_alloc()))) + return -1; + P4e(P4, addr).value |= flags | PAGE_PRESENT; + + if((!P3e(P4, addr).present) + && (!(P3e(P4, addr).value = pmm_alloc()))) + return -1; + P3e(P4, addr).value |= flags | PAGE_PRESENT; + + if((!P2e(P4, addr).present) + && (!(P2e(P4, addr).value = pmm_alloc()))) + return -1; + P2e(P4, addr).value |= flags | PAGE_PRESENT; return 0; } diff --git a/src/kernel/memory/vmm.tt b/src/kernel/memory/vmm.tt index 79178c5..b9b7d57 100644 --- a/src/kernel/memory/vmm.tt +++ b/src/kernel/memory/vmm.tt @@ -119,6 +119,7 @@ uintptr_t pmm_alloc() { uintptr_t *pages[] = {p3, p2, p1}; static int counter=0; + if(counter >= 3) return 0; return (uintptr_t)pages[counter++]; } @@ -146,3 +147,9 @@ TEST(touch_page_sets_flags) ASSERT_EQ_PTR(p2[0], (uintptr_t)p1 | 0x123 | PAGE_PRESENT); } +TEST(touch_page_fails_if_out_of_pages) +{ + pmm_alloc(); + int retval = touch_page(p4, 0, 0); + ASSERT_NEQ_INT(retval, 0); +}