diff options
Diffstat (limited to 'arch/arm64/kernel/head.S')
| -rw-r--r-- | arch/arm64/kernel/head.S | 33 |
1 files changed, 33 insertions, 0 deletions
diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S index 70c462bbd6bf..7397555f8437 100644 --- a/arch/arm64/kernel/head.S +++ b/arch/arm64/kernel/head.S @@ -263,6 +263,39 @@ SYM_FUNC_END(clear_page_tables) populate_entries \tbl, \rtbl, \istart, \iend, \flags, #SWAPPER_BLOCK_SIZE, \tmp .endm +/* + * Remap a subregion created with the map_memory macro with modified attributes + * or output address. The entire remapped region must have been covered in the + * invocation of map_memory. + * + * x0: last level table address (returned in first argument to map_memory) + * x1: start VA of the existing mapping + * x2: start VA of the region to update + * x3: end VA of the region to update (exclusive) + * x4: start PA associated with the region to update + * x5: attributes to set on the updated region + * x6: order of the last level mappings + */ +SYM_FUNC_START_LOCAL(remap_region) + sub x3, x3, #1 // make end inclusive + + // Get the index offset for the start of the last level table + lsr x1, x1, x6 + bfi x1, xzr, #0, #PAGE_SHIFT - 3 + + // Derive the start and end indexes into the last level table + // associated with the provided region + lsr x2, x2, x6 + lsr x3, x3, x6 + sub x2, x2, x1 + sub x3, x3, x1 + + mov x1, #1 + lsl x6, x1, x6 // block size at this level + + populate_entries x0, x4, x2, x3, x5, x6, x7 + ret +SYM_FUNC_END(remap_region) SYM_FUNC_START_LOCAL(create_idmap) adrp x0, idmap_pg_dir |