The pmd containing memblock_limit is cleared by prepare_page_table() which creates the opportunity for early_alloc() to allocate unmapped memory if memblock_limit is not pmd aligned causing a boot-time hang. Commit 965278dcb8ab ("ARM: 8356/1: mm: handle non-pmd-aligned end of RAM") attempted to resolve this problem, but there is a path through the adjust_lowmem_bounds() routine where if all memory regions start and end on pmd-aligned addresses the memblock_limit will be set to arm_lowmem_limit. Since arm_lowmem_limit can be affected by the vmalloc early parameter, the value of arm_lowmem_limit may not be pmd-aligned. This commit corrects this oversight such that memblock_limit is always rounded down to pmd-alignment.
Unified · Split
| @@ -1218,15 +1218,15 @@ void __init adjust_lowmem_bounds(void) · 1217 unmodified lines | ||
| 1218 | 1218 | |
| 1219 | 1219 | high_memory = __va(arm_lowmem_limit - 1) + 1; |
| 1220 | 1220 | |
| 1221 | + if (!memblock_limit) | |
| 1222 | + memblock_limit = arm_lowmem_limit; | |
| 1223 | + | |
| 1221 | 1224 | /* |
| 1222 | 1225 | * Round the memblock limit down to a pmd size. This |
| 1223 | 1226 | * helps to ensure that we will allocate memory from the |
| 1224 | 1227 | * last full pmd, which should be mapped. |
| 1225 | 1228 | */ |
| 1226 | − if (memblock_limit) | |
| 1227 | − memblock_limit = round_down(memblock_limit, PMD_SIZE); | |
| 1228 | − if (!memblock_limit) | |
| 1229 | − memblock_limit = arm_lowmem_limit; | |
| 1229 | + memblock_limit = round_down(memblock_limit, PMD_SIZE); | |
| 1230 | 1230 | |
| 1231 | 1231 | if (!IS_ENABLED(CONFIG_HIGHMEM) || cache_is_vipt_aliasing()) { |
| 1232 | 1232 | if (memblock_end_of_DRAM() > arm_lowmem_limit) { |