Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 37DD2C433F5 for ; Sun, 26 Dec 2021 09:16:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232671AbhLZJH4 (ORCPT ); Sun, 26 Dec 2021 04:07:56 -0500 Received: from smtp2.ustc.edu.cn ([202.38.64.46]:48636 "EHLO ustc.edu.cn" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S231529AbhLZJHz (ORCPT ); Sun, 26 Dec 2021 04:07:55 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=mail.ustc.edu.cn; s=dkim; h=Received:Date:From:To:Cc:Subject: Message-ID:In-Reply-To:References:MIME-Version:Content-Type: Content-Transfer-Encoding; bh=KSm2E0Q7gyRZEOeMZaEjmP0qEA4+OqTwc8 0xfFrGwY0=; b=mMIAy5nfA9Q+S5LtKtVAjA5SgACXqakprqFRmuNIpdtncISu+2 mflTJwERABBZo86xv6NReTdjOOt4Um6+HExyPP9TkNVoA26KOpjrrSrTD5+grbmb 123oAqF3JukNWD+XLNJddVauV4T/nwhbxB7CZGZee5H+Q4Kmr904uHv+Q= Received: from xhacker (unknown [101.86.42.35]) by newmailweb.ustc.edu.cn (Coremail) with SMTP id LkAmygCnrkamMMhhprnCAA--.15306S2; Sun, 26 Dec 2021 17:06:47 +0800 (CST) Date: Sun, 26 Dec 2021 16:59:32 +0800 From: Jisheng Zhang To: Alexandre Ghiti Cc: Jonathan Corbet , Paul Walmsley , Palmer Dabbelt , Albert Ou , Zong Li , Anup Patel , Atish Patra , Christoph Hellwig , Andrey Ryabinin , Alexander Potapenko , Andrey Konovalov , Dmitry Vyukov , Ard Biesheuvel , Arnd Bergmann , Kees Cook , Guo Ren , Heinrich Schuchardt , Mayuresh Chitale , panqinglin2020@iscas.ac.cn, linux-doc@vger.kernel.org, linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, kasan-dev@googlegroups.com, linux-efi@vger.kernel.org, linux-arch@vger.kernel.org Subject: Re: [PATCH v3 07/13] riscv: Implement sv48 support Message-ID: <20211226165932.1ded6f73@xhacker> In-Reply-To: <20211206104657.433304-8-alexandre.ghiti@canonical.com> References: <20211206104657.433304-1-alexandre.ghiti@canonical.com> <20211206104657.433304-8-alexandre.ghiti@canonical.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-CM-TRANSID: LkAmygCnrkamMMhhprnCAA--.15306S2 X-Coremail-Antispam: 1UD129KBjvAXoW3tFy3Xw15tFWkAr1kWFWfXwb_yoW8XrW8Zo WxtF42ga1rWw13Cws5Z3W2gFWjvr1vvrZxZ3yYyrW5tFn2qwnYkr48K3ykJw1UGryfKa43 Wa109ayDXFsYy3s8n29KB7ZKAUJUUUUU529EdanIXcx71UUUUU7v73VFW2AGmfu7bjvjm3 AaLaJ3UjIYCTnIWjp_UUUYO7k0a2IF6w4kM7kC6x804xWl14x267AKxVW5JVWrJwAFc2x0 x2IEx4CE42xK8VAvwI8IcIk0rVWrJVCq3wAFIxvE14AKwVWUJVWUGwA2ocxC64kIII0Yj4 1l84x0c7CEw4AK67xGY2AK021l84ACjcxK6xIIjxv20xvE14v26ryj6F1UM28EF7xvwVC0 I7IYx2IY6xkF7I0E14v26F4j6r4UJwA2z4x0Y4vEx4A2jsIE14v26rxl6s0DM28EF7xvwV C2z280aVCY1x0267AKxVW0oVCq3wAS0I0E0xvYzxvE52x082IY62kv0487Mc02F40EFcxC 0VAKzVAqx4xG6I80ewAv7VC0I7IYx2IY67AKxVWUJVWUGwAv7VC2z280aVAFwI0_Jr0_Gr 1lOx8S6xCaFVCjc4AY6r1j6r4UM4x0Y48IcVAKI48JM4IIrI8v6xkF7I0E8cxan2IY04v7 MxAIw28IcxkI7VAKI48JMxC20s026xCaFVCjc4AY6r1j6r4UMI8I3I0E5I8CrVAFwI0_Jr 0_Jr4lx2IqxVCjr7xvwVAFwI0_JrI_JrWlx4CE17CEb7AF67AKxVW8ZVWrXwCIc40Y0x0E wIxGrwCI42IY6xIIjxv20xvE14v26r1j6r1xMIIF0xvE2Ix0cI8IcVCY1x0267AKxVW8JV WxJwCI42IY6xAIw20EY4v20xvaj40_Wr1j6rW3Jr1lIxAIcVC2z280aVAFwI0_Jr0_Gr1l IxAIcVC2z280aVCY1x0267AKxVW8JVW8JrUvcSsGvfC2KfnxnUUI43ZEXa7IU5q385UUUU U== X-CM-SenderInfo: xmv2xttqjtqzxdloh3xvwfhvlgxou0/ Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 6 Dec 2021 11:46:51 +0100 Alexandre Ghiti wrote: > By adding a new 4th level of page table, give the possibility to 64bit > kernel to address 2^48 bytes of virtual address: in practice, that offers > 128TB of virtual address space to userspace and allows up to 64TB of > physical memory. > > If the underlying hardware does not support sv48, we will automatically > fallback to a standard 3-level page table by folding the new PUD level into > PGDIR level. In order to detect HW capabilities at runtime, we > use SATP feature that ignores writes with an unsupported mode. > > Signed-off-by: Alexandre Ghiti > --- > arch/riscv/Kconfig | 4 +- > arch/riscv/include/asm/csr.h | 3 +- > arch/riscv/include/asm/fixmap.h | 1 + > arch/riscv/include/asm/kasan.h | 6 +- > arch/riscv/include/asm/page.h | 14 ++ > arch/riscv/include/asm/pgalloc.h | 40 +++++ > arch/riscv/include/asm/pgtable-64.h | 108 +++++++++++- > arch/riscv/include/asm/pgtable.h | 24 ++- > arch/riscv/kernel/head.S | 3 +- > arch/riscv/mm/context.c | 4 +- > arch/riscv/mm/init.c | 212 +++++++++++++++++++++--- > arch/riscv/mm/kasan_init.c | 137 ++++++++++++++- > drivers/firmware/efi/libstub/efi-stub.c | 2 + > 13 files changed, 514 insertions(+), 44 deletions(-) > > diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig > index ac6c0cd9bc29..d28fe0148e13 100644 > --- a/arch/riscv/Kconfig > +++ b/arch/riscv/Kconfig > @@ -150,7 +150,7 @@ config PAGE_OFFSET > hex > default 0xC0000000 if 32BIT > default 0x80000000 if 64BIT && !MMU > - default 0xffffffd800000000 if 64BIT > + default 0xffffaf8000000000 if 64BIT > > config KASAN_SHADOW_OFFSET > hex > @@ -201,7 +201,7 @@ config FIX_EARLYCON_MEM > > config PGTABLE_LEVELS > int > - default 3 if 64BIT > + default 4 if 64BIT > default 2 > > config LOCKDEP_SUPPORT > diff --git a/arch/riscv/include/asm/csr.h b/arch/riscv/include/asm/csr.h > index 87ac65696871..3fdb971c7896 100644 > --- a/arch/riscv/include/asm/csr.h > +++ b/arch/riscv/include/asm/csr.h > @@ -40,14 +40,13 @@ > #ifndef CONFIG_64BIT > #define SATP_PPN _AC(0x003FFFFF, UL) > #define SATP_MODE_32 _AC(0x80000000, UL) > -#define SATP_MODE SATP_MODE_32 > #define SATP_ASID_BITS 9 > #define SATP_ASID_SHIFT 22 > #define SATP_ASID_MASK _AC(0x1FF, UL) > #else > #define SATP_PPN _AC(0x00000FFFFFFFFFFF, UL) > #define SATP_MODE_39 _AC(0x8000000000000000, UL) > -#define SATP_MODE SATP_MODE_39 > +#define SATP_MODE_48 _AC(0x9000000000000000, UL) > #define SATP_ASID_BITS 16 > #define SATP_ASID_SHIFT 44 > #define SATP_ASID_MASK _AC(0xFFFF, UL) > diff --git a/arch/riscv/include/asm/fixmap.h b/arch/riscv/include/asm/fixmap.h > index 54cbf07fb4e9..58a718573ad6 100644 > --- a/arch/riscv/include/asm/fixmap.h > +++ b/arch/riscv/include/asm/fixmap.h > @@ -24,6 +24,7 @@ enum fixed_addresses { > FIX_HOLE, > FIX_PTE, > FIX_PMD, > + FIX_PUD, > FIX_TEXT_POKE1, > FIX_TEXT_POKE0, > FIX_EARLYCON_MEM_BASE, > diff --git a/arch/riscv/include/asm/kasan.h b/arch/riscv/include/asm/kasan.h > index 743e6ff57996..0b85e363e778 100644 > --- a/arch/riscv/include/asm/kasan.h > +++ b/arch/riscv/include/asm/kasan.h > @@ -28,7 +28,11 @@ > #define KASAN_SHADOW_SCALE_SHIFT 3 > > #define KASAN_SHADOW_SIZE (UL(1) << ((VA_BITS - 1) - KASAN_SHADOW_SCALE_SHIFT)) > -#define KASAN_SHADOW_START (KASAN_SHADOW_END - KASAN_SHADOW_SIZE) > +/* > + * Depending on the size of the virtual address space, the region may not be > + * aligned on PGDIR_SIZE, so force its alignment to ease its population. > + */ > +#define KASAN_SHADOW_START ((KASAN_SHADOW_END - KASAN_SHADOW_SIZE) & PGDIR_MASK) > #define KASAN_SHADOW_END MODULES_LOWEST_VADDR > #define KASAN_SHADOW_OFFSET _AC(CONFIG_KASAN_SHADOW_OFFSET, UL) > > diff --git a/arch/riscv/include/asm/page.h b/arch/riscv/include/asm/page.h > index e03559f9b35e..d089fe46f7d8 100644 > --- a/arch/riscv/include/asm/page.h > +++ b/arch/riscv/include/asm/page.h > @@ -31,7 +31,20 @@ > * When not using MMU this corresponds to the first free page in > * physical memory (aligned on a page boundary). > */ > +#ifdef CONFIG_64BIT > +#ifdef CONFIG_MMU > +#define PAGE_OFFSET kernel_map.page_offset > +#else > +#define PAGE_OFFSET _AC(CONFIG_PAGE_OFFSET, UL) > +#endif > +/* > + * By default, CONFIG_PAGE_OFFSET value corresponds to SV48 address space so > + * define the PAGE_OFFSET value for SV39. > + */ > +#define PAGE_OFFSET_L3 _AC(0xffffffd800000000, UL) > +#else > #define PAGE_OFFSET _AC(CONFIG_PAGE_OFFSET, UL) > +#endif /* CONFIG_64BIT */ > > /* > * Half of the kernel address space (half of the entries of the page global > @@ -90,6 +103,7 @@ extern unsigned long riscv_pfn_base; > #endif /* CONFIG_MMU */ > > struct kernel_mapping { > + unsigned long page_offset; > unsigned long virt_addr; > uintptr_t phys_addr; > uintptr_t size; > diff --git a/arch/riscv/include/asm/pgalloc.h b/arch/riscv/include/asm/pgalloc.h > index 0af6933a7100..11823004b87a 100644 > --- a/arch/riscv/include/asm/pgalloc.h > +++ b/arch/riscv/include/asm/pgalloc.h > @@ -11,6 +11,8 @@ > #include > > #ifdef CONFIG_MMU > +#define __HAVE_ARCH_PUD_ALLOC_ONE > +#define __HAVE_ARCH_PUD_FREE > #include > > static inline void pmd_populate_kernel(struct mm_struct *mm, > @@ -36,6 +38,44 @@ static inline void pud_populate(struct mm_struct *mm, pud_t *pud, pmd_t *pmd) > > set_pud(pud, __pud((pfn << _PAGE_PFN_SHIFT) | _PAGE_TABLE)); > } > + > +static inline void p4d_populate(struct mm_struct *mm, p4d_t *p4d, pud_t *pud) > +{ > + if (pgtable_l4_enabled) { > + unsigned long pfn = virt_to_pfn(pud); > + > + set_p4d(p4d, __p4d((pfn << _PAGE_PFN_SHIFT) | _PAGE_TABLE)); > + } > +} > + > +static inline void p4d_populate_safe(struct mm_struct *mm, p4d_t *p4d, > + pud_t *pud) > +{ > + if (pgtable_l4_enabled) { > + unsigned long pfn = virt_to_pfn(pud); > + > + set_p4d_safe(p4d, > + __p4d((pfn << _PAGE_PFN_SHIFT) | _PAGE_TABLE)); > + } > +} > + > +#define pud_alloc_one pud_alloc_one > +static inline pud_t *pud_alloc_one(struct mm_struct *mm, unsigned long addr) > +{ > + if (pgtable_l4_enabled) > + return __pud_alloc_one(mm, addr); > + > + return NULL; > +} > + > +#define pud_free pud_free > +static inline void pud_free(struct mm_struct *mm, pud_t *pud) > +{ > + if (pgtable_l4_enabled) > + __pud_free(mm, pud); > +} > + > +#define __pud_free_tlb(tlb, pud, addr) pud_free((tlb)->mm, pud) > #endif /* __PAGETABLE_PMD_FOLDED */ > > static inline pgd_t *pgd_alloc(struct mm_struct *mm) > diff --git a/arch/riscv/include/asm/pgtable-64.h b/arch/riscv/include/asm/pgtable-64.h > index 228261aa9628..bbbdd66e5e2f 100644 > --- a/arch/riscv/include/asm/pgtable-64.h > +++ b/arch/riscv/include/asm/pgtable-64.h > @@ -8,16 +8,36 @@ > > #include > > -#define PGDIR_SHIFT 30 > +extern bool pgtable_l4_enabled; > + > +#define PGDIR_SHIFT_L3 30 > +#define PGDIR_SHIFT_L4 39 > +#define PGDIR_SIZE_L3 (_AC(1, UL) << PGDIR_SHIFT_L3) > + > +#define PGDIR_SHIFT (pgtable_l4_enabled ? PGDIR_SHIFT_L4 : PGDIR_SHIFT_L3) > /* Size of region mapped by a page global directory */ > #define PGDIR_SIZE (_AC(1, UL) << PGDIR_SHIFT) > #define PGDIR_MASK (~(PGDIR_SIZE - 1)) > > +/* pud is folded into pgd in case of 3-level page table */ > +#define PUD_SHIFT 30 > +#define PUD_SIZE (_AC(1, UL) << PUD_SHIFT) > +#define PUD_MASK (~(PUD_SIZE - 1)) > + > #define PMD_SHIFT 21 > /* Size of region mapped by a page middle directory */ > #define PMD_SIZE (_AC(1, UL) << PMD_SHIFT) > #define PMD_MASK (~(PMD_SIZE - 1)) > > +/* Page Upper Directory entry */ > +typedef struct { > + unsigned long pud; > +} pud_t; > + > +#define pud_val(x) ((x).pud) > +#define __pud(x) ((pud_t) { (x) }) > +#define PTRS_PER_PUD (PAGE_SIZE / sizeof(pud_t)) > + > /* Page Middle Directory entry */ > typedef struct { > unsigned long pmd; > @@ -59,6 +79,16 @@ static inline void pud_clear(pud_t *pudp) > set_pud(pudp, __pud(0)); > } > > +static inline pud_t pfn_pud(unsigned long pfn, pgprot_t prot) > +{ > + return __pud((pfn << _PAGE_PFN_SHIFT) | pgprot_val(prot)); > +} > + > +static inline unsigned long _pud_pfn(pud_t pud) > +{ > + return pud_val(pud) >> _PAGE_PFN_SHIFT; > +} > + > static inline pmd_t *pud_pgtable(pud_t pud) > { > return (pmd_t *)pfn_to_virt(pud_val(pud) >> _PAGE_PFN_SHIFT); > @@ -69,6 +99,17 @@ static inline struct page *pud_page(pud_t pud) > return pfn_to_page(pud_val(pud) >> _PAGE_PFN_SHIFT); > } > > +#define mm_pud_folded mm_pud_folded > +static inline bool mm_pud_folded(struct mm_struct *mm) > +{ > + if (pgtable_l4_enabled) > + return false; > + > + return true; > +} > + > +#define pmd_index(addr) (((addr) >> PMD_SHIFT) & (PTRS_PER_PMD - 1)) > + > static inline pmd_t pfn_pmd(unsigned long pfn, pgprot_t prot) > { > return __pmd((pfn << _PAGE_PFN_SHIFT) | pgprot_val(prot)); > @@ -84,4 +125,69 @@ static inline unsigned long _pmd_pfn(pmd_t pmd) > #define pmd_ERROR(e) \ > pr_err("%s:%d: bad pmd %016lx.\n", __FILE__, __LINE__, pmd_val(e)) > > +#define pud_ERROR(e) \ > + pr_err("%s:%d: bad pud %016lx.\n", __FILE__, __LINE__, pud_val(e)) > + > +static inline void set_p4d(p4d_t *p4dp, p4d_t p4d) > +{ > + if (pgtable_l4_enabled) > + *p4dp = p4d; > + else > + set_pud((pud_t *)p4dp, (pud_t){ p4d_val(p4d) }); > +} > + > +static inline int p4d_none(p4d_t p4d) > +{ > + if (pgtable_l4_enabled) > + return (p4d_val(p4d) == 0); > + > + return 0; > +} > + > +static inline int p4d_present(p4d_t p4d) > +{ > + if (pgtable_l4_enabled) > + return (p4d_val(p4d) & _PAGE_PRESENT); > + > + return 1; > +} > + > +static inline int p4d_bad(p4d_t p4d) > +{ > + if (pgtable_l4_enabled) > + return !p4d_present(p4d); > + > + return 0; > +} > + > +static inline void p4d_clear(p4d_t *p4d) > +{ > + if (pgtable_l4_enabled) > + set_p4d(p4d, __p4d(0)); > +} > + > +static inline pud_t *p4d_pgtable(p4d_t p4d) > +{ > + if (pgtable_l4_enabled) > + return (pud_t *)pfn_to_virt(p4d_val(p4d) >> _PAGE_PFN_SHIFT); > + > + return (pud_t *)pud_pgtable((pud_t) { p4d_val(p4d) }); > +} > + > +static inline struct page *p4d_page(p4d_t p4d) > +{ > + return pfn_to_page(p4d_val(p4d) >> _PAGE_PFN_SHIFT); > +} > + > +#define pud_index(addr) (((addr) >> PUD_SHIFT) & (PTRS_PER_PUD - 1)) > + > +#define pud_offset pud_offset > +static inline pud_t *pud_offset(p4d_t *p4d, unsigned long address) > +{ > + if (pgtable_l4_enabled) > + return p4d_pgtable(*p4d) + pud_index(address); > + > + return (pud_t *)p4d; > +} > + > #endif /* _ASM_RISCV_PGTABLE_64_H */ > diff --git a/arch/riscv/include/asm/pgtable.h b/arch/riscv/include/asm/pgtable.h > index e1a52e22ad7e..e1c74ef4ead2 100644 > --- a/arch/riscv/include/asm/pgtable.h > +++ b/arch/riscv/include/asm/pgtable.h > @@ -51,7 +51,7 @@ > * position vmemmap directly below the VMALLOC region. > */ > #ifdef CONFIG_64BIT > -#define VA_BITS 39 > +#define VA_BITS (pgtable_l4_enabled ? 48 : 39) > #else > #define VA_BITS 32 > #endif > @@ -90,8 +90,7 @@ > > #ifndef __ASSEMBLY__ > > -/* Page Upper Directory not used in RISC-V */ > -#include > +#include > #include > #include > #include > @@ -113,6 +112,17 @@ > #define XIP_FIXUP(addr) (addr) > #endif /* CONFIG_XIP_KERNEL */ > > +struct pt_alloc_ops { > + pte_t *(*get_pte_virt)(phys_addr_t pa); > + phys_addr_t (*alloc_pte)(uintptr_t va); > +#ifndef __PAGETABLE_PMD_FOLDED > + pmd_t *(*get_pmd_virt)(phys_addr_t pa); > + phys_addr_t (*alloc_pmd)(uintptr_t va); > + pud_t *(*get_pud_virt)(phys_addr_t pa); > + phys_addr_t (*alloc_pud)(uintptr_t va); > +#endif > +}; > + > #ifdef CONFIG_MMU > /* Number of entries in the page global directory */ > #define PTRS_PER_PGD (PAGE_SIZE / sizeof(pgd_t)) > @@ -669,9 +679,11 @@ static inline pmd_t pmdp_establish(struct vm_area_struct *vma, > * Note that PGDIR_SIZE must evenly divide TASK_SIZE. > */ > #ifdef CONFIG_64BIT > -#define TASK_SIZE (PGDIR_SIZE * PTRS_PER_PGD / 2) > +#define TASK_SIZE (PGDIR_SIZE * PTRS_PER_PGD / 2) > +#define TASK_SIZE_MIN (PGDIR_SIZE_L3 * PTRS_PER_PGD / 2) > #else > -#define TASK_SIZE FIXADDR_START > +#define TASK_SIZE FIXADDR_START > +#define TASK_SIZE_MIN TASK_SIZE > #endif > > #else /* CONFIG_MMU */ > @@ -697,6 +709,8 @@ extern uintptr_t _dtb_early_pa; > #define dtb_early_va _dtb_early_va > #define dtb_early_pa _dtb_early_pa > #endif /* CONFIG_XIP_KERNEL */ > +extern u64 satp_mode; > +extern bool pgtable_l4_enabled; > > void paging_init(void); > void misc_mem_init(void); > diff --git a/arch/riscv/kernel/head.S b/arch/riscv/kernel/head.S > index 52c5ff9804c5..c3c0ed559770 100644 > --- a/arch/riscv/kernel/head.S > +++ b/arch/riscv/kernel/head.S > @@ -95,7 +95,8 @@ relocate: > > /* Compute satp for kernel page tables, but don't load it yet */ > srl a2, a0, PAGE_SHIFT > - li a1, SATP_MODE > + la a1, satp_mode > + REG_L a1, 0(a1) > or a2, a2, a1 > > /* > diff --git a/arch/riscv/mm/context.c b/arch/riscv/mm/context.c > index ee3459cb6750..a7246872bd30 100644 > --- a/arch/riscv/mm/context.c > +++ b/arch/riscv/mm/context.c > @@ -192,7 +192,7 @@ static void set_mm_asid(struct mm_struct *mm, unsigned int cpu) > switch_mm_fast: > csr_write(CSR_SATP, virt_to_pfn(mm->pgd) | > ((cntx & asid_mask) << SATP_ASID_SHIFT) | > - SATP_MODE); > + satp_mode); > > if (need_flush_tlb) > local_flush_tlb_all(); > @@ -201,7 +201,7 @@ static void set_mm_asid(struct mm_struct *mm, unsigned int cpu) > static void set_mm_noasid(struct mm_struct *mm) > { > /* Switch the page table and blindly nuke entire local TLB */ > - csr_write(CSR_SATP, virt_to_pfn(mm->pgd) | SATP_MODE); > + csr_write(CSR_SATP, virt_to_pfn(mm->pgd) | satp_mode); > local_flush_tlb_all(); > } > > diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c > index 1552226fb6bd..6a19a1b1caf8 100644 > --- a/arch/riscv/mm/init.c > +++ b/arch/riscv/mm/init.c > @@ -37,6 +37,17 @@ EXPORT_SYMBOL(kernel_map); > #define kernel_map (*(struct kernel_mapping *)XIP_FIXUP(&kernel_map)) > #endif > > +#ifdef CONFIG_64BIT > +u64 satp_mode = !IS_ENABLED(CONFIG_XIP_KERNEL) ? SATP_MODE_48 : SATP_MODE_39; > +#else > +u64 satp_mode = SATP_MODE_32; > +#endif > +EXPORT_SYMBOL(satp_mode); > + > +bool pgtable_l4_enabled = IS_ENABLED(CONFIG_64BIT) && !IS_ENABLED(CONFIG_XIP_KERNEL) ? > + true : false; Hi Alex, I'm not sure whether we can use static key for pgtable_l4_enabled or not. Obviously, for a specific HW platform, pgtable_l4_enabled won't change after boot, and it seems it sits hot code path, so IMHO, static key maybe suitable for it. Thanks