x86/mm/ident_map: Add 5-level paging support
Add additional page table level handing. It's mostly mechanical.
The only quirk is that with p4d folded, 'pgd' is equal to 'p4d' in
kernel_ident_mapping_init(). The pgd entry has to point to the pud
page table in this case.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-arch@vger.kernel.org
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/20170313143309.16020-5-kirill.shutemov@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
diff --git a/arch/x86/mm/ident_map.c b/arch/x86/mm/ident_map.c
index 4473cb4..04210a2 100644
--- a/arch/x86/mm/ident_map.c
+++ b/arch/x86/mm/ident_map.c
@@ -45,6 +45,34 @@ static int ident_pud_init(struct x86_mapping_info *info, pud_t *pud_page,
return 0;
}
+static int ident_p4d_init(struct x86_mapping_info *info, p4d_t *p4d_page,
+ unsigned long addr, unsigned long end)
+{
+ unsigned long next;
+
+ for (; addr < end; addr = next) {
+ p4d_t *p4d = p4d_page + p4d_index(addr);
+ pud_t *pud;
+
+ next = (addr & P4D_MASK) + P4D_SIZE;
+ if (next > end)
+ next = end;
+
+ if (p4d_present(*p4d)) {
+ pud = pud_offset(p4d, 0);
+ ident_pud_init(info, pud, addr, next);
+ continue;
+ }
+ pud = (pud_t *)info->alloc_pgt_page(info->context);
+ if (!pud)
+ return -ENOMEM;
+ ident_pud_init(info, pud, addr, next);
+ set_p4d(p4d, __p4d(__pa(pud) | _KERNPG_TABLE));
+ }
+
+ return 0;
+}
+
int kernel_ident_mapping_init(struct x86_mapping_info *info, pgd_t *pgd_page,
unsigned long pstart, unsigned long pend)
{
@@ -55,27 +83,36 @@ int kernel_ident_mapping_init(struct x86_mapping_info *info, pgd_t *pgd_page,
for (; addr < end; addr = next) {
pgd_t *pgd = pgd_page + pgd_index(addr);
- pud_t *pud;
+ p4d_t *p4d;
next = (addr & PGDIR_MASK) + PGDIR_SIZE;
if (next > end)
next = end;
if (pgd_present(*pgd)) {
- pud = pud_offset(pgd, 0);
- result = ident_pud_init(info, pud, addr, next);
+ p4d = p4d_offset(pgd, 0);
+ result = ident_p4d_init(info, p4d, addr, next);
if (result)
return result;
continue;
}
- pud = (pud_t *)info->alloc_pgt_page(info->context);
- if (!pud)
+ p4d = (p4d_t *)info->alloc_pgt_page(info->context);
+ if (!p4d)
return -ENOMEM;
- result = ident_pud_init(info, pud, addr, next);
+ result = ident_p4d_init(info, p4d, addr, next);
if (result)
return result;
- set_pgd(pgd, __pgd(__pa(pud) | _KERNPG_TABLE));
+ if (IS_ENABLED(CONFIG_X86_5LEVEL)) {
+ set_pgd(pgd, __pgd(__pa(p4d) | _KERNPG_TABLE));
+ } else {
+ /*
+ * With p4d folded, pgd is equal to p4d.
+ * The pgd entry has to point to the pud page table in this case.
+ */
+ pud_t *pud = pud_offset(p4d, 0);
+ set_pgd(pgd, __pgd(__pa(pud) | _KERNPG_TABLE));
+ }
}
return 0;