diff options
| author | Anton Kling <anton@kling.gg> | 2024-12-14 16:29:45 +0100 |
|---|---|---|
| committer | Anton Kling <anton@kling.gg> | 2024-12-14 16:29:45 +0100 |
| commit | 36a627c83e3e91bad7482efd0b7af2de5d53902a (patch) | |
| tree | 231ead4f20908b29335eabb08e01afd1805b8b2a | |
| parent | 79d326a7eface8e79b76c6584c4beba935159a45 (diff) | |
mmu: Remove recursion in ksbrk
Due to buggy edge cases it caused logic bugs which caused stack
overflows. There should be no need to make any additional checks after
the table was created anyways so it is better to just skip it.
| -rw-r--r-- | kernel/arch/i386/mmu.c | 9 |
1 files changed, 6 insertions, 3 deletions
diff --git a/kernel/arch/i386/mmu.c b/kernel/arch/i386/mmu.c index d46b077..ba7259b 100644 --- a/kernel/arch/i386/mmu.c +++ b/kernel/arch/i386/mmu.c @@ -31,6 +31,7 @@ int mmu_allocate_kernel_linear_virtual_to_physical_mapping(void *rc, size_t n); static int create_kernel_table(int table_index) { u32 physical; + kernel_directory->tables[table_index] = (PageTable *)0xDEADBEEF; active_directory->tables[table_index] = (PageTable *)0xDEADBEEF; PageTable *new_table = (PageTable *)ksbrk_physical(sizeof(PageTable), (void **)&physical); @@ -55,13 +56,13 @@ static int create_kernel_table(int table_index) { void *ksbrk(size_t s, int enforce_linear) { uintptr_t rc = (uintptr_t)align_page((void *)data_end); - data_end += s; - data_end = (uintptr_t)align_page((void *)data_end); if (!get_active_pagedirectory()) { // If there is no active pagedirectory we // just assume that the memory is // already mapped. + data_end += s; + data_end = (uintptr_t)align_page((void *)data_end); return (void *)rc; } // Determine whether we are approaching a unallocated table @@ -70,8 +71,10 @@ void *ksbrk(size_t s, int enforce_linear) { if (!create_kernel_table(table_index)) { return NULL; } - return ksbrk(s, enforce_linear); + rc = (uintptr_t)align_page((void *)data_end); } + data_end += s; + data_end = (uintptr_t)align_page((void *)data_end); if (enforce_linear) { if (!mmu_allocate_kernel_linear_virtual_to_physical_mapping( (void *)rc, (data_end - (uintptr_t)rc))) { |