diff options
| author | Benjamin Berg <benjamin.berg@intel.com> | 2024-09-19 14:45:11 +0200 |
|---|---|---|
| committer | Johannes Berg <johannes.berg@intel.com> | 2024-10-10 13:37:22 +0200 |
| commit | 41ab5fe7471ff38d2909d1c93b88197a89c6a00f (patch) | |
| tree | ea76a3b75fd7d8d2b7a4be194e74081113d0b595 /arch/um/kernel/mem.c | |
| parent | e167cc7a95fe01e228e403ac90090f8613e7d8bc (diff) | |
um: Switch to 4 level page tables on 64 bit
The larger memory space is useful to support more applications inside
UML. One example for this is ASAN instrumentation of userspace
applications which requires addresses that would otherwise not be
available.
Signed-off-by: Benjamin Berg <benjamin.berg@intel.com>
Link: https://patch.msgid.link/20240919124511.282088-11-benjamin@sipsolutions.net
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Diffstat (limited to 'arch/um/kernel/mem.c')
| -rw-r--r-- | arch/um/kernel/mem.c | 17 |
1 files changed, 16 insertions, 1 deletions
diff --git a/arch/um/kernel/mem.c b/arch/um/kernel/mem.c index 5026668dc054..53248ed04771 100644 --- a/arch/um/kernel/mem.c +++ b/arch/um/kernel/mem.c @@ -95,7 +95,7 @@ static void __init one_page_table_init(pmd_t *pmd) static void __init one_md_table_init(pud_t *pud) { -#ifdef CONFIG_3_LEVEL_PGTABLES +#if CONFIG_PGTABLE_LEVELS > 2 pmd_t *pmd_table = (pmd_t *) memblock_alloc_low(PAGE_SIZE, PAGE_SIZE); if (!pmd_table) panic("%s: Failed to allocate %lu bytes align=%lx\n", @@ -106,6 +106,19 @@ static void __init one_md_table_init(pud_t *pud) #endif } +static void __init one_ud_table_init(p4d_t *p4d) +{ +#if CONFIG_PGTABLE_LEVELS > 3 + pud_t *pud_table = (pud_t *) memblock_alloc_low(PAGE_SIZE, PAGE_SIZE); + if (!pud_table) + panic("%s: Failed to allocate %lu bytes align=%lx\n", + __func__, PAGE_SIZE, PAGE_SIZE); + + set_p4d(p4d, __p4d(_KERNPG_TABLE + (unsigned long) __pa(pud_table))); + BUG_ON(pud_table != pud_offset(p4d, 0)); +#endif +} + static void __init fixrange_init(unsigned long start, unsigned long end, pgd_t *pgd_base) { @@ -123,6 +136,8 @@ static void __init fixrange_init(unsigned long start, unsigned long end, for ( ; (i < PTRS_PER_PGD) && (vaddr < end); pgd++, i++) { p4d = p4d_offset(pgd, vaddr); + if (p4d_none(*p4d)) + one_ud_table_init(p4d); pud = pud_offset(p4d, vaddr); if (pud_none(*pud)) one_md_table_init(pud); |