[PATCH RFC 09/17] arm64: text replication: add node 0 page table definitions

[Russell King (Oracle)]

Add a struct definition for the level zero page table group (the
optional trampoline page tables, reserved page tables, and swapper page
tables).

Add a symbol and extern declaration for the node 0 page table group.

Add an array of pointers to per-node page tables, which will default to
using the node 0 page table group.

Signed-off-by: Russell King (Oracle) <rmk+kernel at armlinux.org.uk>
---
 arch/arm64/include/asm/pgtable.h | 14 ++++++++++++++
 arch/arm64/kernel/vmlinux.lds.S  |  3 +++
 arch/arm64/mm/ktext.c            |  4 ++++
 3 files changed, 21 insertions(+)

diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
index cb526e69299d..1e72067d1e9e 100644
--- a/arch/arm64/include/asm/pgtable.h
+++ b/arch/arm64/include/asm/pgtable.h
@@ -615,6 +615,20 @@ extern pgd_t idmap_pg_dir[PTRS_PER_PGD];
 extern pgd_t tramp_pg_dir[PTRS_PER_PGD];
 extern pgd_t reserved_pg_dir[PTRS_PER_PGD];
 
+struct pgtables {
+#ifdef CONFIG_UNMAP_KERNEL_AT_EL0
+	pgd_t tramp_pg_dir[PTRS_PER_PGD];
+#endif
+	pgd_t reserved_pg_dir[PTRS_PER_PGD];
+	pgd_t swapper_pg_dir[PTRS_PER_PGD];
+};
+
+extern struct pgtables pgtable_node0;
+
+#ifdef CONFIG_REPLICATE_KTEXT
+extern struct pgtables *pgtables[MAX_NUMNODES];
+#endif
+
 extern void set_swapper_pgd(pgd_t *pgdp, pgd_t pgd);
 
 static inline bool in_swapper_pgdir(void *addr)
diff --git a/arch/arm64/kernel/vmlinux.lds.S b/arch/arm64/kernel/vmlinux.lds.S
index 3cd7e76cc562..d3c7ed76adbf 100644
--- a/arch/arm64/kernel/vmlinux.lds.S
+++ b/arch/arm64/kernel/vmlinux.lds.S
@@ -212,6 +212,9 @@ SECTIONS
 	idmap_pg_dir = .;
 	. += PAGE_SIZE;
 
+	/* pgtable struct - covers the tramp, reserved and swapper pgdirs */
+	pgtable_node0 = .;
+
 #ifdef CONFIG_UNMAP_KERNEL_AT_EL0
 	tramp_pg_dir = .;
 	. += PAGE_SIZE;
diff --git a/arch/arm64/mm/ktext.c b/arch/arm64/mm/ktext.c
index 80120b5fd29f..85fc97877d75 100644
--- a/arch/arm64/mm/ktext.c
+++ b/arch/arm64/mm/ktext.c
@@ -15,6 +15,10 @@
 #include <asm/ktext.h>
 #include <asm/memory.h>
 
+struct pgtables *pgtables[MAX_NUMNODES] = {
+	[0 ... MAX_NUMNODES - 1] = &pgtable_node0,
+};
+
 static void *kernel_texts[MAX_NUMNODES];
 
 void __kprobes ktext_replication_patch(u32 *tp, __le32 insn)
-- 
2.30.2