From: Ryan Roberts <ryan.roberts@xxxxxxx> Sent: Monday, October 14, 2024 3:59 AM > > Introduce a new Kconfig, ARM64_BOOT_TIME_PAGE_SIZE, which can be > selected instead of a page size. When selected, the resulting kernel's > page size can be configured at boot via the command line. > > For now, boot-time page size kernels are limited to 48-bit VA, since > more work is required to support LPA2. Additionally MMAP_RND_BITS and > SECTION_SIZE_BITS are configured for the worst case (64K pages). Future > work could be implemented to be able to configure these at boot time for > optimial page size-specific values. > > 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/Kconfig | 26 ++++++++++--- > arch/arm64/include/asm/kvm_hyp.h | 11 ++++++ > arch/arm64/include/asm/pgtable-geometry.h | 22 ++++++++++- > arch/arm64/include/asm/pgtable-hwdef.h | 6 +-- > arch/arm64/include/asm/pgtable.h | 10 ++++- > arch/arm64/include/asm/sparsemem.h | 4 ++ > arch/arm64/kernel/image-vars.h | 11 ++++++ > arch/arm64/kernel/image.h | 4 ++ > arch/arm64/kernel/pi/map_kernel.c | 45 ++++++++++++++++++++++ > arch/arm64/kvm/arm.c | 10 +++++ > arch/arm64/kvm/hyp/nvhe/Makefile | 1 + > arch/arm64/kvm/hyp/nvhe/pgtable-geometry.c | 16 ++++++++ > arch/arm64/mm/Makefile | 1 + > arch/arm64/mm/pgd.c | 10 +++-- > arch/arm64/mm/pgtable-geometry.c | 24 ++++++++++++ > drivers/firmware/efi/libstub/arm64.c | 3 +- > 16 files changed, 187 insertions(+), 17 deletions(-) > create mode 100644 arch/arm64/kvm/hyp/nvhe/pgtable-geometry.c > create mode 100644 arch/arm64/mm/pgtable-geometry.c > > diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig > index a2f8ff354ca67..573d308741169 100644 > --- a/arch/arm64/Kconfig > +++ b/arch/arm64/Kconfig > @@ -121,6 +121,7 @@ config ARM64 > select BUILDTIME_TABLE_SORT > select CLONE_BACKWARDS > select COMMON_CLK > + select CONSTRUCTORS if ARM64_BOOT_TIME_PAGE_SIZE > select CPU_PM if (SUSPEND || CPU_IDLE) > select CPUMASK_OFFSTACK if NR_CPUS > 256 > select CRC32 > @@ -284,18 +285,20 @@ config MMU > > config ARM64_CONT_PTE_SHIFT > int > + depends on !ARM64_BOOT_TIME_PAGE_SIZE > default 5 if PAGE_SIZE_64KB > default 7 if PAGE_SIZE_16KB > default 4 > > config ARM64_CONT_PMD_SHIFT > int > + depends on !ARM64_BOOT_TIME_PAGE_SIZE > default 5 if PAGE_SIZE_64KB > default 5 if PAGE_SIZE_16KB > default 4 > > config ARCH_MMAP_RND_BITS_MIN > - default 14 if PAGE_SIZE_64KB > + default 14 if ARM64_64K_PAGES || ARM64_BOOT_TIME_PAGE_SIZE > default 16 if PAGE_SIZE_16KB > default 18 > > @@ -306,15 +309,15 @@ config ARCH_MMAP_RND_BITS_MAX > default 24 if ARM64_VA_BITS=39 > default 27 if ARM64_VA_BITS=42 > default 30 if ARM64_VA_BITS=47 > - default 29 if ARM64_VA_BITS=48 && ARM64_64K_PAGES > + default 29 if ARM64_VA_BITS=48 && (ARM64_64K_PAGES || > ARM64_BOOT_TIME_PAGE_SIZE) > default 31 if ARM64_VA_BITS=48 && ARM64_16K_PAGES > default 33 if ARM64_VA_BITS=48 > - default 14 if ARM64_64K_PAGES > + default 14 if ARM64_64K_PAGES || ARM64_BOOT_TIME_PAGE_SIZE > default 16 if ARM64_16K_PAGES > default 18 > > config ARCH_MMAP_RND_COMPAT_BITS_MIN > - default 7 if ARM64_64K_PAGES > + default 7 if ARM64_64K_PAGES || ARM64_BOOT_TIME_PAGE_SIZE > default 9 if ARM64_16K_PAGES > default 11 > > @@ -362,6 +365,7 @@ config FIX_EARLYCON_MEM > > config PGTABLE_LEVELS > int > + default 4 if ARM64_BOOT_TIME_PAGE_SIZE # Advertise max supported levels > default 2 if ARM64_16K_PAGES && ARM64_VA_BITS_36 > default 2 if ARM64_64K_PAGES && ARM64_VA_BITS_42 > default 3 if ARM64_64K_PAGES && (ARM64_VA_BITS_48 || > ARM64_VA_BITS_52) > @@ -1316,6 +1320,14 @@ config ARM64_64K_PAGES > look-up. AArch32 emulation requires applications compiled > with 64K aligned segments. > > +config ARM64_BOOT_TIME_PAGE_SIZE > + bool "Boot-time selection" > + select HAVE_PAGE_SIZE_64KB # Advertise largest page size to core > + help > + Select desired page size (4KB, 16KB or 64KB) at boot-time via the > + kernel command line option "arm64.pagesize=4k", "arm64.pagesize=16k" > + or "arm64.pagesize=64k". > + > endchoice > > choice > @@ -1348,6 +1360,7 @@ config ARM64_VA_BITS_48 > config ARM64_VA_BITS_52 > bool "52-bit" > depends on ARM64_PAN || !ARM64_SW_TTBR0_PAN > + depends on !ARM64_BOOT_TIME_PAGE_SIZE > help > Enable 52-bit virtual addressing for userspace when explicitly > requested via a hint to mmap(). The kernel will also use 52-bit > @@ -1588,9 +1601,10 @@ config XEN > # 4K | 27 | 12 | 15 | 10 | > # 16K | 27 | 14 | 13 | 11 | > # 64K | 29 | 16 | 13 | 13 | > +# BOOT| 29 | 16 (max) | 13 | 13 | > config ARCH_FORCE_MAX_ORDER > int > - default "13" if ARM64_64K_PAGES > + default "13" if ARM64_64K_PAGES || ARM64_BOOT_TIME_PAGE_SIZE > default "11" if ARM64_16K_PAGES > default "10" > help > @@ -1663,7 +1677,7 @@ config ARM64_TAGGED_ADDR_ABI > > menuconfig COMPAT > bool "Kernel support for 32-bit EL0" > - depends on ARM64_4K_PAGES || EXPERT > + depends on ARM64_4K_PAGES || ARM64_BOOT_TIME_PAGE_SIZE || EXPERT > select HAVE_UID16 > select OLD_SIGSUSPEND3 > select COMPAT_OLD_SIGACTION > diff --git a/arch/arm64/include/asm/kvm_hyp.h > b/arch/arm64/include/asm/kvm_hyp.h > index c838309e4ec47..9397a14642afa 100644 > --- a/arch/arm64/include/asm/kvm_hyp.h > +++ b/arch/arm64/include/asm/kvm_hyp.h > @@ -145,4 +145,15 @@ extern unsigned long kvm_nvhe_sym(__icache_flags); > extern unsigned int kvm_nvhe_sym(kvm_arm_vmid_bits); > extern unsigned int kvm_nvhe_sym(kvm_host_sve_max_vl); > > +#ifdef CONFIG_ARM64_BOOT_TIME_PAGE_SIZE > +extern int kvm_nvhe_sym(ptg_page_shift); > +extern int kvm_nvhe_sym(ptg_pmd_shift); > +extern int kvm_nvhe_sym(ptg_pud_shift); > +extern int kvm_nvhe_sym(ptg_p4d_shift); > +extern int kvm_nvhe_sym(ptg_pgdir_shift); > +extern int kvm_nvhe_sym(ptg_cont_pte_shift); > +extern int kvm_nvhe_sym(ptg_cont_pmd_shift); > +extern int kvm_nvhe_sym(ptg_pgtable_levels); > +#endif /* CONFIG_ARM64_BOOT_TIME_PAGE_SIZE */ > + > #endif /* __ARM64_KVM_HYP_H__ */ > diff --git a/arch/arm64/include/asm/pgtable-geometry.h > b/arch/arm64/include/asm/pgtable-geometry.h > index 62fe125909c08..18a8c8d499ecc 100644 > --- a/arch/arm64/include/asm/pgtable-geometry.h > +++ b/arch/arm64/include/asm/pgtable-geometry.h > @@ -6,16 +6,33 @@ > #define ARM64_PAGE_SHIFT_16K 14 > #define ARM64_PAGE_SHIFT_64K 16 > > +#ifdef CONFIG_ARM64_BOOT_TIME_PAGE_SIZE > +#define PAGE_SHIFT_MIN ARM64_PAGE_SHIFT_4K > +#define PAGE_SHIFT_MAX ARM64_PAGE_SHIFT_64K > +#else /* CONFIG_ARM64_BOOT_TIME_PAGE_SIZE */ > #define PAGE_SHIFT_MIN CONFIG_PAGE_SHIFT > +#define PAGE_SHIFT_MAX CONFIG_PAGE_SHIFT > +#endif /* CONFIG_ARM64_BOOT_TIME_PAGE_SIZE */ > + > #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> > > +#ifdef CONFIG_ARM64_BOOT_TIME_PAGE_SIZE > +#ifndef __ASSEMBLY__ > +extern int ptg_page_shift; > +extern int ptg_pmd_shift; > +extern int ptg_pud_shift; > +extern int ptg_p4d_shift; > +extern int ptg_pgdir_shift; > +extern int ptg_cont_pte_shift; > +extern int ptg_cont_pmd_shift; > +extern int ptg_pgtable_levels; > +#endif /* __ASSEMBLY__ */ > +#else /* CONFIG_ARM64_BOOT_TIME_PAGE_SIZE */ > #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) > @@ -24,5 +41,6 @@ > #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 /* CONFIG_ARM64_BOOT_TIME_PAGE_SIZE */ > > #endif /* ASM_PGTABLE_GEOMETRY_H */ > diff --git a/arch/arm64/include/asm/pgtable-hwdef.h > b/arch/arm64/include/asm/pgtable-hwdef.h > index ca8bcbc1fe220..da5404617acbf 100644 > --- a/arch/arm64/include/asm/pgtable-hwdef.h > +++ b/arch/arm64/include/asm/pgtable-hwdef.h > @@ -52,7 +52,7 @@ > #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 PTRS_PER_PMD (ptg_pgtable_levels > 2 ? (1 << (PAGE_SHIFT - > 3)) : 1) > #define MAX_PTRS_PER_PMD (1 << (PAGE_SHIFT_MAX - 3)) > #endif > > @@ -63,7 +63,7 @@ > #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 PTRS_PER_PUD (ptg_pgtable_levels > 3 ? (1 << (PAGE_SHIFT - > 3)) : 1) > #define MAX_PTRS_PER_PUD (1 << (PAGE_SHIFT_MAX - 3)) > #endif > > @@ -71,7 +71,7 @@ > #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 PTRS_PER_P4D (ptg_pgtable_levels > 4 ? (1 << (PAGE_SHIFT - > 3)) : 1) > #define MAX_PTRS_PER_P4D (1 << (PAGE_SHIFT_MAX - 3)) > #endif > > diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h > index 8ead41da715b0..ad9f75f5cc29a 100644 > --- a/arch/arm64/include/asm/pgtable.h > +++ b/arch/arm64/include/asm/pgtable.h > @@ -755,7 +755,7 @@ static inline unsigned long pmd_page_vaddr(pmd_t pmd) > > static __always_inline bool pgtable_l3_enabled(void) > { > - return true; > + return ptg_pgtable_levels > 2; > } > > static inline bool mm_pmd_folded(const struct mm_struct *mm) > @@ -888,6 +888,8 @@ static inline bool pgtable_l3_enabled(void) { return false; } > > static __always_inline bool pgtable_l4_enabled(void) > { > + if (IS_ENABLED(CONFIG_ARM64_BOOT_TIME_PAGE_SIZE)) > + return ptg_pgtable_levels > 3; > if (CONFIG_PGTABLE_LEVELS > 4 || !IS_ENABLED(CONFIG_ARM64_LPA2)) > return true; > if (!alternative_has_cap_likely(ARM64_ALWAYS_BOOT)) > @@ -935,6 +937,8 @@ static inline phys_addr_t p4d_page_paddr(p4d_t p4d) > > static inline pud_t *p4d_to_folded_pud(p4d_t *p4dp, unsigned long addr) > { > + if (IS_ENABLED(CONFIG_ARM64_BOOT_TIME_PAGE_SIZE)) > + return (pud_t *)p4dp; > return (pud_t *)PTR_ALIGN_DOWN(p4dp, PAGE_SIZE) + pud_index(addr); > } > > @@ -1014,6 +1018,8 @@ static inline bool pgtable_l4_enabled(void) { return false; } > > static __always_inline bool pgtable_l5_enabled(void) > { > + if (IS_ENABLED(CONFIG_ARM64_BOOT_TIME_PAGE_SIZE)) > + return ptg_pgtable_levels > 4; > if (!alternative_has_cap_likely(ARM64_ALWAYS_BOOT)) > return vabits_actual == VA_BITS; > return alternative_has_cap_unlikely(ARM64_HAS_VA52); > @@ -1059,6 +1065,8 @@ static inline phys_addr_t pgd_page_paddr(pgd_t pgd) > > static inline p4d_t *pgd_to_folded_p4d(pgd_t *pgdp, unsigned long addr) > { > + if (IS_ENABLED(CONFIG_ARM64_BOOT_TIME_PAGE_SIZE)) > + return (p4d_t *)pgdp; > return (p4d_t *)PTR_ALIGN_DOWN(pgdp, PAGE_SIZE) + p4d_index(addr); > } > > diff --git a/arch/arm64/include/asm/sparsemem.h > b/arch/arm64/include/asm/sparsemem.h > index a05fdd54014f7..2daf1263ba638 100644 > --- a/arch/arm64/include/asm/sparsemem.h > +++ b/arch/arm64/include/asm/sparsemem.h > @@ -17,6 +17,10 @@ > * entries could not be created for vmemmap mappings. > * 16K follows 4K for simplicity. > */ > +#ifdef CONFIG_ARM64_BOOT_TIME_PAGE_SIZE > +#define SECTION_SIZE_BITS 29 > +#else > #define SECTION_SIZE_BITS (PAGE_SIZE == SZ_64K ? 29 : 27) > +#endif > > #endif > diff --git a/arch/arm64/kernel/image-vars.h b/arch/arm64/kernel/image-vars.h > index a168f3337446f..9968320f83bc4 100644 > --- a/arch/arm64/kernel/image-vars.h > +++ b/arch/arm64/kernel/image-vars.h > @@ -36,6 +36,17 @@ PROVIDE(__pi___memcpy = > __pi_memcpy); > PROVIDE(__pi___memmove = __pi_memmove); > PROVIDE(__pi___memset = __pi_memset); > > +#ifdef CONFIG_ARM64_BOOT_TIME_PAGE_SIZE > +PROVIDE(__pi_ptg_page_shift = ptg_page_shift); > +PROVIDE(__pi_ptg_pmd_shift = ptg_pmd_shift); > +PROVIDE(__pi_ptg_pud_shift = ptg_pud_shift); > +PROVIDE(__pi_ptg_p4d_shift = ptg_p4d_shift); > +PROVIDE(__pi_ptg_pgdir_shift = ptg_pgdir_shift); > +PROVIDE(__pi_ptg_cont_pte_shift = ptg_cont_pte_shift); > +PROVIDE(__pi_ptg_cont_pmd_shift = ptg_cont_pmd_shift); > +PROVIDE(__pi_ptg_pgtable_levels = ptg_pgtable_levels); > +#endif /* CONFIG_ARM64_BOOT_TIME_PAGE_SIZE */ > + > PROVIDE(__pi_id_aa64isar1_override = id_aa64isar1_override); > PROVIDE(__pi_id_aa64isar2_override = id_aa64isar2_override); > PROVIDE(__pi_id_aa64mmfr0_override = id_aa64mmfr0_override); > diff --git a/arch/arm64/kernel/image.h b/arch/arm64/kernel/image.h > index 7bc3ba8979019..01502fc3b891b 100644 > --- a/arch/arm64/kernel/image.h > +++ b/arch/arm64/kernel/image.h > @@ -47,7 +47,11 @@ > #define __HEAD_FLAG_BE ARM64_IMAGE_FLAG_LE > #endif > > +#ifdef CONFIG_ARM64_BOOT_TIME_PAGE_SIZE > +#define __HEAD_FLAG_PAGE_SIZE 0 > +#else > #define __HEAD_FLAG_PAGE_SIZE ((PAGE_SHIFT - 10) / 2) > +#endif > > #define __HEAD_FLAG_PHYS_BASE 1 > > diff --git a/arch/arm64/kernel/pi/map_kernel.c b/arch/arm64/kernel/pi/map_kernel.c > index deb8cd50b0b0c..22b3c70e04f9c 100644 > --- a/arch/arm64/kernel/pi/map_kernel.c > +++ b/arch/arm64/kernel/pi/map_kernel.c > @@ -221,6 +221,49 @@ static void __init map_fdt(u64 fdt, int page_shift) > dsb(ishst); > } > > +#ifdef CONFIG_ARM64_BOOT_TIME_PAGE_SIZE > +static void __init ptg_init(int page_shift) > +{ > + ptg_pgtable_levels = > + __ARM64_HW_PGTABLE_LEVELS(page_shift, > CONFIG_ARM64_VA_BITS); > + > + ptg_pgdir_shift = __ARM64_HW_PGTABLE_LEVEL_SHIFT(page_shift, > + 4 - ptg_pgtable_levels); > + > + ptg_p4d_shift = ptg_pgtable_levels >= 5 ? > + __ARM64_HW_PGTABLE_LEVEL_SHIFT(page_shift, 0) : > + ptg_pgdir_shift; > + > + ptg_pud_shift = ptg_pgtable_levels >= 4 ? > + __ARM64_HW_PGTABLE_LEVEL_SHIFT(page_shift, 1) : > + ptg_pgdir_shift; > + > + ptg_pmd_shift = ptg_pgtable_levels >= 3 ? > + __ARM64_HW_PGTABLE_LEVEL_SHIFT(page_shift, 2) : > + ptg_pgdir_shift; > + > + ptg_page_shift = page_shift; > + > + switch (page_shift) { > + case ARM64_PAGE_SHIFT_64K: > + ptg_cont_pte_shift = ptg_page_shift + 5; > + ptg_cont_pmd_shift = ptg_pmd_shift + 5; > + break; > + case ARM64_PAGE_SHIFT_16K: > + ptg_cont_pte_shift = ptg_page_shift + 7; > + ptg_cont_pmd_shift = ptg_pmd_shift + 5; > + break; > + default: /* ARM64_PAGE_SHIFT_4K */ > + ptg_cont_pte_shift = ptg_page_shift + 4; > + ptg_cont_pmd_shift = ptg_pmd_shift + 4; > + } > +} > +#else /* CONFIG_ARM64_BOOT_TIME_PAGE_SIZE */ > +static inline void ptg_init(int page_shift) > +{ > +} > +#endif /* CONFIG_ARM64_BOOT_TIME_PAGE_SIZE */ > + > asmlinkage void __init early_map_kernel(u64 boot_status, void *fdt) > { > static char const chosen_str[] __initconst = "/chosen"; > @@ -247,6 +290,8 @@ asmlinkage void __init early_map_kernel(u64 boot_status, void > *fdt) > if (!page_shift) > page_shift = early_page_shift; > > + ptg_init(page_shift); > + > if (va_bits > 48) { > u64 page_size = early_page_size(page_shift); > > diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c > index 9bef7638342ef..c835a50b8b768 100644 > --- a/arch/arm64/kvm/arm.c > +++ b/arch/arm64/kvm/arm.c > @@ -2424,6 +2424,16 @@ static void kvm_hyp_init_symbols(void) > kvm_nvhe_sym(id_aa64smfr0_el1_sys_val) = > read_sanitised_ftr_reg(SYS_ID_AA64SMFR0_EL1); > kvm_nvhe_sym(__icache_flags) = __icache_flags; > kvm_nvhe_sym(kvm_arm_vmid_bits) = kvm_arm_vmid_bits; > +#ifdef CONFIG_ARM64_BOOT_TIME_PAGE_SIZE > + kvm_nvhe_sym(ptg_page_shift) = ptg_page_shift; > + kvm_nvhe_sym(ptg_pmd_shift) = ptg_pmd_shift; > + kvm_nvhe_sym(ptg_pud_shift) = ptg_pud_shift; > + kvm_nvhe_sym(ptg_p4d_shift) = ptg_p4d_shift; > + kvm_nvhe_sym(ptg_pgdir_shift) = ptg_pgdir_shift; > + kvm_nvhe_sym(ptg_cont_pte_shift) = ptg_cont_pte_shift; > + kvm_nvhe_sym(ptg_cont_pmd_shift) = ptg_cont_pmd_shift; > + kvm_nvhe_sym(ptg_pgtable_levels) = ptg_pgtable_levels; > +#endif /* CONFIG_ARM64_BOOT_TIME_PAGE_SIZE */ > } > > static int __init kvm_hyp_init_protection(u32 hyp_va_bits) > diff --git a/arch/arm64/kvm/hyp/nvhe/Makefile > b/arch/arm64/kvm/hyp/nvhe/Makefile > index b43426a493df5..a8fcbb84c7996 100644 > --- a/arch/arm64/kvm/hyp/nvhe/Makefile > +++ b/arch/arm64/kvm/hyp/nvhe/Makefile > @@ -27,6 +27,7 @@ hyp-obj-y := timer-sr.o sysreg-sr.o debug-sr.o switch.o tlb.o hyp- > init.o host.o > cache.o setup.o mm.o mem_protect.o sys_regs.o pkvm.o stacktrace.o ffa.o > hyp-obj-y += ../vgic-v3-sr.o ../aarch32.o ../vgic-v2-cpuif-proxy.o ../entry.o \ > ../fpsimd.o ../hyp-entry.o ../exception.o ../pgtable.o > +hyp-obj-$(CONFIG_ARM64_BOOT_TIME_PAGE_SIZE) += pgtable-geometry.o > hyp-obj-$(CONFIG_LIST_HARDENED) += list_debug.o > hyp-obj-y += $(lib-objs) > > diff --git a/arch/arm64/kvm/hyp/nvhe/pgtable-geometry.c > b/arch/arm64/kvm/hyp/nvhe/pgtable-geometry.c > new file mode 100644 > index 0000000000000..17f807450a31a > --- /dev/null > +++ b/arch/arm64/kvm/hyp/nvhe/pgtable-geometry.c > @@ -0,0 +1,16 @@ > +// SPDX-License-Identifier: GPL-2.0-only > +/* > + * Copyright (C) 2024 ARM Ltd. > + */ > + > +#include <linux/cache.h> > +#include <asm/pgtable-geometry.h> > + > +int ptg_page_shift __ro_after_init; > +int ptg_pmd_shift __ro_after_init; > +int ptg_pud_shift __ro_after_init; > +int ptg_p4d_shift __ro_after_init; > +int ptg_pgdir_shift __ro_after_init; > +int ptg_cont_pte_shift __ro_after_init; > +int ptg_cont_pmd_shift __ro_after_init; > +int ptg_pgtable_levels __ro_after_init; > diff --git a/arch/arm64/mm/Makefile b/arch/arm64/mm/Makefile > index 60454256945b8..2ba30d06b35fe 100644 > --- a/arch/arm64/mm/Makefile > +++ b/arch/arm64/mm/Makefile > @@ -3,6 +3,7 @@ obj-y := dma-mapping.o extable.o > fault.o init.o \ > cache.o copypage.o flush.o \ > ioremap.o mmap.o pgd.o mmu.o \ > context.o proc.o pageattr.o fixmap.o > +obj-$(CONFIG_ARM64_BOOT_TIME_PAGE_SIZE) += pgtable-geometry.o > obj-$(CONFIG_ARM64_CONTPTE) += contpte.o > obj-$(CONFIG_HUGETLB_PAGE) += hugetlbpage.o > obj-$(CONFIG_PTDUMP_CORE) += ptdump.o > diff --git a/arch/arm64/mm/pgd.c b/arch/arm64/mm/pgd.c > index 4b106510358b1..c052d0dcb0c69 100644 > --- a/arch/arm64/mm/pgd.c > +++ b/arch/arm64/mm/pgd.c > @@ -21,10 +21,12 @@ static bool pgdir_is_page_size(void) > { > if (PGD_SIZE == PAGE_SIZE) > return true; > - if (CONFIG_PGTABLE_LEVELS == 4) > - return !pgtable_l4_enabled(); > - if (CONFIG_PGTABLE_LEVELS == 5) > - return !pgtable_l5_enabled(); > + if (!IS_ENABLED(CONFIG_ARM64_BOOT_TIME_PAGE_SIZE)) { > + if (CONFIG_PGTABLE_LEVELS == 4) > + return !pgtable_l4_enabled(); > + if (CONFIG_PGTABLE_LEVELS == 5) > + return !pgtable_l5_enabled(); > + } > return false; > } > > diff --git a/arch/arm64/mm/pgtable-geometry.c b/arch/arm64/mm/pgtable- > geometry.c > new file mode 100644 > index 0000000000000..ba50637f1e9d0 > --- /dev/null > +++ b/arch/arm64/mm/pgtable-geometry.c > @@ -0,0 +1,24 @@ > +// SPDX-License-Identifier: GPL-2.0-only > +/* > + * Copyright (C) 2024 ARM Ltd. > + */ > + > +#include <linux/cache.h> > +#include <asm/pgtable-geometry.h> > + > +/* > + * TODO: These should be __ro_after_init, but we need to write to them from the > + * pi code where they are mapped in the early page table as read-only. > + * __ro_after_init doesn't become writable until later when the swapper pgtable > + * is fully set up. We should update the early page table to map __ro_after_init > + * as read-write. > + */ > + > +int ptg_page_shift __read_mostly; > +int ptg_pmd_shift __read_mostly; I found that ptg_page_shift and ptg_pmd_shift need EXPORT_SYMBOL_GPL for cases where code compiled as a module is using PAGE_SIZE/PAGE_SHIFT or PMD_SIZE/PMD_SHIFT. Some of the others below might also need EXPORT_SYMBOL_GPL. Michael > +int ptg_pud_shift __read_mostly; > +int ptg_p4d_shift __read_mostly; > +int ptg_pgdir_shift __read_mostly; > +int ptg_cont_pte_shift __read_mostly; > +int ptg_cont_pmd_shift __read_mostly; > +int ptg_pgtable_levels __read_mostly; > diff --git a/drivers/firmware/efi/libstub/arm64.c > b/drivers/firmware/efi/libstub/arm64.c > index e57cd3de0a00f..8db9dba7d5423 100644 > --- a/drivers/firmware/efi/libstub/arm64.c > +++ b/drivers/firmware/efi/libstub/arm64.c > @@ -68,7 +68,8 @@ efi_status_t check_platform_features(void) > efi_novamap = true; > > /* UEFI mandates support for 4 KB granularity, no need to check */ > - if (IS_ENABLED(CONFIG_ARM64_4K_PAGES)) > + if (IS_ENABLED(CONFIG_ARM64_4K_PAGES) || > + IS_ENABLED(CONFIG_ARM64_BOOT_TIME_PAGE_SIZE)) > return EFI_SUCCESS; > > tg = (read_cpuid(ID_AA64MMFR0_EL1) >> > ID_AA64MMFR0_EL1_TGRAN_SHIFT) & 0xf; > -- > 2.43.0 >
