[RFC PATCH v1 39/57] arm64: Introduce macros required for boot-time page selection

[Ryan Roberts]

This minmal set of macros will allow boot-time page selection support to
be added to the arm64 arch code incrementally over the following set of
patches.

The definitions in pgtable-geometry.h are for compile-time page size
currently, but they will be modified in future to support boot-time page
size.

Signed-off-by: Ryan Roberts <ryan.roberts@xxxxxxx>
---

***NOTE***
Any confused maintainers may want to read the cover note here for context:
https://lore.kernel.org/all/20241014105514.3206191-1-ryan.roberts@xxxxxxx/

 arch/arm64/include/asm/page-def.h         |  5 ++--
 arch/arm64/include/asm/pgtable-geometry.h | 28 +++++++++++++++++++++++
 arch/arm64/include/asm/pgtable-hwdef.h    | 16 ++++++++-----
 3 files changed, 40 insertions(+), 9 deletions(-)
 create mode 100644 arch/arm64/include/asm/pgtable-geometry.h

diff --git a/arch/arm64/include/asm/page-def.h b/arch/arm64/include/asm/page-def.h
index d69971cf49cd2..b99dee0112463 100644
--- a/arch/arm64/include/asm/page-def.h
+++ b/arch/arm64/include/asm/page-def.h
@@ -9,12 +9,11 @@
 #define __ASM_PAGE_DEF_H
 
 #include <linux/const.h>
+#include <asm/pgtable-geometry.h>
 
 /* PAGE_SHIFT determines the page size */
-#define PAGE_SHIFT		CONFIG_PAGE_SHIFT
+#define PAGE_SHIFT		ptg_page_shift
 #define PAGE_SIZE		(_AC(1, UL) << PAGE_SHIFT)
 #define PAGE_MASK		(~(PAGE_SIZE-1))
 
-#include <asm-generic/pgtable-geometry.h>
-
 #endif /* __ASM_PAGE_DEF_H */
diff --git a/arch/arm64/include/asm/pgtable-geometry.h b/arch/arm64/include/asm/pgtable-geometry.h
new file mode 100644
index 0000000000000..62fe125909c08
--- /dev/null
+++ b/arch/arm64/include/asm/pgtable-geometry.h
@@ -0,0 +1,28 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+#ifndef ASM_PGTABLE_GEOMETRY_H
+#define ASM_PGTABLE_GEOMETRY_H
+
+#define ARM64_PAGE_SHIFT_4K	12
+#define ARM64_PAGE_SHIFT_16K	14
+#define ARM64_PAGE_SHIFT_64K	16
+
+#define PAGE_SHIFT_MIN		CONFIG_PAGE_SHIFT
+#define PAGE_SIZE_MIN		(_AC(1, UL) << PAGE_SHIFT_MIN)
+#define PAGE_MASK_MIN		(~(PAGE_SIZE_MIN-1))
+
+#define PAGE_SHIFT_MAX		CONFIG_PAGE_SHIFT
+#define PAGE_SIZE_MAX		(_AC(1, UL) << PAGE_SHIFT_MAX)
+#define PAGE_MASK_MAX		(~(PAGE_SIZE_MAX-1))
+
+#include <asm-generic/pgtable-geometry.h>
+
+#define ptg_page_shift		CONFIG_PAGE_SHIFT
+#define ptg_pmd_shift		ARM64_HW_PGTABLE_LEVEL_SHIFT(2)
+#define ptg_pud_shift		ARM64_HW_PGTABLE_LEVEL_SHIFT(1)
+#define ptg_p4d_shift		ARM64_HW_PGTABLE_LEVEL_SHIFT(0)
+#define ptg_pgdir_shift		ARM64_HW_PGTABLE_LEVEL_SHIFT(4 - CONFIG_PGTABLE_LEVELS)
+#define ptg_cont_pte_shift	(CONFIG_ARM64_CONT_PTE_SHIFT + PAGE_SHIFT)
+#define ptg_cont_pmd_shift	(CONFIG_ARM64_CONT_PMD_SHIFT + PMD_SHIFT)
+#define ptg_pgtable_levels	CONFIG_PGTABLE_LEVELS
+
+#endif /* ASM_PGTABLE_GEOMETRY_H */
diff --git a/arch/arm64/include/asm/pgtable-hwdef.h b/arch/arm64/include/asm/pgtable-hwdef.h
index 1f60aa1bc750c..54a9153f56bc5 100644
--- a/arch/arm64/include/asm/pgtable-hwdef.h
+++ b/arch/arm64/include/asm/pgtable-hwdef.h
@@ -41,39 +41,43 @@
 #define ARM64_HW_PGTABLE_LEVEL_SHIFT(n)	((PAGE_SHIFT - 3) * (4 - (n)) + 3)
 
 #define PTRS_PER_PTE		(1 << (PAGE_SHIFT - 3))
+#define MAX_PTRS_PER_PTE	(1 << (PAGE_SHIFT_MAX - 3))
 
 /*
  * PMD_SHIFT determines the size a level 2 page table entry can map.
  */
 #if CONFIG_PGTABLE_LEVELS > 2
-#define PMD_SHIFT		ARM64_HW_PGTABLE_LEVEL_SHIFT(2)
+#define PMD_SHIFT		ptg_pmd_shift
 #define PMD_SIZE		(_AC(1, UL) << PMD_SHIFT)
 #define PMD_MASK		(~(PMD_SIZE-1))
 #define PTRS_PER_PMD		(1 << (PAGE_SHIFT - 3))
+#define MAX_PTRS_PER_PMD	(1 << (PAGE_SHIFT_MAX - 3))
 #endif
 
 /*
  * PUD_SHIFT determines the size a level 1 page table entry can map.
  */
 #if CONFIG_PGTABLE_LEVELS > 3
-#define PUD_SHIFT		ARM64_HW_PGTABLE_LEVEL_SHIFT(1)
+#define PUD_SHIFT		ptg_pud_shift
 #define PUD_SIZE		(_AC(1, UL) << PUD_SHIFT)
 #define PUD_MASK		(~(PUD_SIZE-1))
 #define PTRS_PER_PUD		(1 << (PAGE_SHIFT - 3))
+#define MAX_PTRS_PER_PUD	(1 << (PAGE_SHIFT_MAX - 3))
 #endif
 
 #if CONFIG_PGTABLE_LEVELS > 4
-#define P4D_SHIFT		ARM64_HW_PGTABLE_LEVEL_SHIFT(0)
+#define P4D_SHIFT		ptg_p4d_shift
 #define P4D_SIZE		(_AC(1, UL) << P4D_SHIFT)
 #define P4D_MASK		(~(P4D_SIZE-1))
 #define PTRS_PER_P4D		(1 << (PAGE_SHIFT - 3))
+#define MAX_PTRS_PER_P4D	(1 << (PAGE_SHIFT_MAX - 3))
 #endif
 
 /*
  * PGDIR_SHIFT determines the size a top-level page table entry can map
  * (depending on the configuration, this level can be -1, 0, 1 or 2).
  */
-#define PGDIR_SHIFT		ARM64_HW_PGTABLE_LEVEL_SHIFT(4 - CONFIG_PGTABLE_LEVELS)
+#define PGDIR_SHIFT		ptg_pgdir_shift
 #define PGDIR_SIZE		(_AC(1, UL) << PGDIR_SHIFT)
 #define PGDIR_MASK		(~(PGDIR_SIZE-1))
 #define PTRS_PER_PGD		(1 << (VA_BITS - PGDIR_SHIFT))
@@ -81,12 +85,12 @@
 /*
  * Contiguous page definitions.
  */
-#define CONT_PTE_SHIFT		(CONFIG_ARM64_CONT_PTE_SHIFT + PAGE_SHIFT)
+#define CONT_PTE_SHIFT		ptg_cont_pte_shift
 #define CONT_PTES		(1 << (CONT_PTE_SHIFT - PAGE_SHIFT))
 #define CONT_PTE_SIZE		(CONT_PTES * PAGE_SIZE)
 #define CONT_PTE_MASK		(~(CONT_PTE_SIZE - 1))
 
-#define CONT_PMD_SHIFT		(CONFIG_ARM64_CONT_PMD_SHIFT + PMD_SHIFT)
+#define CONT_PMD_SHIFT		ptg_cont_pmd_shift
 #define CONT_PMDS		(1 << (CONT_PMD_SHIFT - PMD_SHIFT))
 #define CONT_PMD_SIZE		(CONT_PMDS * PMD_SIZE)
 #define CONT_PMD_MASK		(~(CONT_PMD_SIZE - 1))
-- 
2.43.0