Re: [PATCH v3 07/13] riscv: Implement sv48 support

From: 潘庆霖
Date: Wed Dec 08 2021 - 23:33:40 EST


Hi Alex,

On 2021/12/6 19:05, Alexandre ghiti wrote:
> On 12/6/21 11:46, 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 <alexandre.ghiti@xxxxxxxxxxxxx>
>> ---
>>   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 <asm/tlb.h>
>>     #ifdef CONFIG_MMU
>> +#define __HAVE_ARCH_PUD_ALLOC_ONE
>> +#define __HAVE_ARCH_PUD_FREE
>>   #include <asm-generic/pgalloc.h>
>>     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 <linux/const.h>
>>   -#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 <asm-generic/pgtable-nopud.h>
>> +#include <asm-generic/pgtable-nop4d.h>
>>   #include <asm/page.h>
>>   #include <asm/tlbflush.h>
>>   #include <linux/mm_types.h>
>> @@ -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;
>> +EXPORT_SYMBOL(pgtable_l4_enabled);
>> +
>>   phys_addr_t phys_ram_base __ro_after_init;
>>   EXPORT_SYMBOL(phys_ram_base);
>>   @@ -53,15 +64,6 @@ extern char _start[];
>>   void *_dtb_early_va __initdata;
>>   uintptr_t _dtb_early_pa __initdata;
>>   -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);
>> -#endif
>> -};
>> -
>>   static phys_addr_t dma32_phys_limit __initdata;
>>     static void __init zone_sizes_init(void)
>> @@ -222,7 +224,7 @@ static void __init setup_bootmem(void)
>>   }
>>     #ifdef CONFIG_MMU
>> -static struct pt_alloc_ops _pt_ops __initdata;
>> +struct pt_alloc_ops _pt_ops __initdata;
>>     #ifdef CONFIG_XIP_KERNEL
>>   #define pt_ops (*(struct pt_alloc_ops *)XIP_FIXUP(&_pt_ops))
>> @@ -238,6 +240,7 @@ pgd_t trampoline_pg_dir[PTRS_PER_PGD] __page_aligned_bss;
>>   static pte_t fixmap_pte[PTRS_PER_PTE] __page_aligned_bss;
>>     pgd_t early_pg_dir[PTRS_PER_PGD] __initdata __aligned(PAGE_SIZE);
>> +static pud_t __maybe_unused early_dtb_pud[PTRS_PER_PUD] __initdata __aligned(PAGE_SIZE);
>>   static pmd_t __maybe_unused early_dtb_pmd[PTRS_PER_PMD] __initdata __aligned(PAGE_SIZE);
>>     #ifdef CONFIG_XIP_KERNEL
>> @@ -326,6 +329,16 @@ static pmd_t early_pmd[PTRS_PER_PMD] __initdata __aligned(PAGE_SIZE);
>>   #define early_pmd      ((pmd_t *)XIP_FIXUP(early_pmd))
>>   #endif /* CONFIG_XIP_KERNEL */
>>   +static pud_t trampoline_pud[PTRS_PER_PUD] __page_aligned_bss;
>> +static pud_t fixmap_pud[PTRS_PER_PUD] __page_aligned_bss;
>> +static pud_t early_pud[PTRS_PER_PUD] __initdata __aligned(PAGE_SIZE);
>> +
>> +#ifdef CONFIG_XIP_KERNEL
>> +#define trampoline_pud ((pud_t *)XIP_FIXUP(trampoline_pud))
>> +#define fixmap_pud     ((pud_t *)XIP_FIXUP(fixmap_pud))
>> +#define early_pud      ((pud_t *)XIP_FIXUP(early_pud))
>> +#endif /* CONFIG_XIP_KERNEL */
>> +
>>   static pmd_t *__init get_pmd_virt_early(phys_addr_t pa)
>>   {
>>       /* Before MMU is enabled */
>> @@ -345,7 +358,7 @@ static pmd_t *__init get_pmd_virt_late(phys_addr_t pa)
>>     static phys_addr_t __init alloc_pmd_early(uintptr_t va)
>>   {
>> -    BUG_ON((va - kernel_map.virt_addr) >> PGDIR_SHIFT);
>> +    BUG_ON((va - kernel_map.virt_addr) >> PUD_SHIFT);
>>         return (uintptr_t)early_pmd;
>>   }
>> @@ -391,21 +404,97 @@ static void __init create_pmd_mapping(pmd_t *pmdp,
>>       create_pte_mapping(ptep, va, pa, sz, prot);
>>   }
>>   -#define pgd_next_t        pmd_t
>> -#define alloc_pgd_next(__va)    pt_ops.alloc_pmd(__va)
>> -#define get_pgd_next_virt(__pa) pt_ops.get_pmd_virt(__pa)
>> +static pud_t *__init get_pud_virt_early(phys_addr_t pa)
>> +{
>> +    return (pud_t *)((uintptr_t)pa);
>> +}
>> +
>> +static pud_t *__init get_pud_virt_fixmap(phys_addr_t pa)
>> +{
>> +    clear_fixmap(FIX_PUD);
>> +    return (pud_t *)set_fixmap_offset(FIX_PUD, pa);
>> +}
>> +
>> +static pud_t *__init get_pud_virt_late(phys_addr_t pa)
>> +{
>> +    return (pud_t *)__va(pa);
>> +}
>> +
>> +static phys_addr_t __init alloc_pud_early(uintptr_t va)
>> +{
>> +    /* Only one PUD is available for early mapping */
>> +    BUG_ON((va - kernel_map.virt_addr) >> PGDIR_SHIFT);
>> +
>> +    return (uintptr_t)early_pud;
>> +}
>> +
>> +static phys_addr_t __init alloc_pud_fixmap(uintptr_t va)
>> +{
>> +    return memblock_phys_alloc(PAGE_SIZE, PAGE_SIZE);
>> +}
>> +
>> +static phys_addr_t alloc_pud_late(uintptr_t va)
>> +{
>> +    unsigned long vaddr;
>> +
>> +    vaddr = __get_free_page(GFP_KERNEL);
>> +    BUG_ON(!vaddr);
>> +    return __pa(vaddr);
>> +}
>> +
>> +static void __init create_pud_mapping(pud_t *pudp,
>> +                      uintptr_t va, phys_addr_t pa,
>> +                      phys_addr_t sz, pgprot_t prot)
>> +{
>> +    pmd_t *nextp;
>> +    phys_addr_t next_phys;
>> +    uintptr_t pud_index = pud_index(va);
>> +
>> +    if (sz == PUD_SIZE) {
>> +        if (pud_val(pudp[pud_index]) == 0)
>> +            pudp[pud_index] = pfn_pud(PFN_DOWN(pa), prot);
>> +        return;
>> +    }
>> +
>> +    if (pud_val(pudp[pud_index]) == 0) {
>> +        next_phys = pt_ops.alloc_pmd(va);
>> +        pudp[pud_index] = pfn_pud(PFN_DOWN(next_phys), PAGE_TABLE);
>> +        nextp = pt_ops.get_pmd_virt(next_phys);
>> +        memset(nextp, 0, PAGE_SIZE);
>> +    } else {
>> +        next_phys = PFN_PHYS(_pud_pfn(pudp[pud_index]));
>> +        nextp = pt_ops.get_pmd_virt(next_phys);
>> +    }
>> +
>> +    create_pmd_mapping(nextp, va, pa, sz, prot);
>> +}
>> +
>> +#define pgd_next_t        pud_t
>> +#define alloc_pgd_next(__va)    (pgtable_l4_enabled ?            \
>> +        pt_ops.alloc_pud(__va) : pt_ops.alloc_pmd(__va))
>> +#define get_pgd_next_virt(__pa)    (pgtable_l4_enabled ?            \
>> +        pt_ops.get_pud_virt(__pa) : (pgd_next_t *)pt_ops.get_pmd_virt(__pa))
>>   #define create_pgd_next_mapping(__nextp, __va, __pa, __sz, __prot)    \
>> -    create_pmd_mapping(__nextp, __va, __pa, __sz, __prot)
>> -#define fixmap_pgd_next        fixmap_pmd
>> +                (pgtable_l4_enabled ?            \
>> +        create_pud_mapping(__nextp, __va, __pa, __sz, __prot) :    \
>> +        create_pmd_mapping((pmd_t *)__nextp, __va, __pa, __sz, __prot))
>> +#define fixmap_pgd_next        (pgtable_l4_enabled ?            \
>> +        (uintptr_t)fixmap_pud : (uintptr_t)fixmap_pmd)
>> +#define trampoline_pgd_next    (pgtable_l4_enabled ?            \
>> +        (uintptr_t)trampoline_pud : (uintptr_t)trampoline_pmd)
>> +#define early_dtb_pgd_next    (pgtable_l4_enabled ?            \
>> +        (uintptr_t)early_dtb_pud : (uintptr_t)early_dtb_pmd)
>>   #else
>>   #define pgd_next_t        pte_t
>>   #define alloc_pgd_next(__va)    pt_ops.alloc_pte(__va)
>>   #define get_pgd_next_virt(__pa) pt_ops.get_pte_virt(__pa)
>>   #define create_pgd_next_mapping(__nextp, __va, __pa, __sz, __prot)    \
>>       create_pte_mapping(__nextp, __va, __pa, __sz, __prot)
>> -#define fixmap_pgd_next        fixmap_pte
>> +#define fixmap_pgd_next        ((uintptr_t)fixmap_pte)
>> +#define early_dtb_pgd_next    ((uintptr_t)early_dtb_pmd)
>> +#define create_pud_mapping(__pmdp, __va, __pa, __sz, __prot)
>>   #define create_pmd_mapping(__pmdp, __va, __pa, __sz, __prot)
>> -#endif
>> +#endif /* __PAGETABLE_PMD_FOLDED */
>>     void __init create_pgd_mapping(pgd_t *pgdp,
>>                         uintptr_t va, phys_addr_t pa,
>> @@ -493,6 +582,57 @@ static __init pgprot_t pgprot_from_va(uintptr_t va)
>>   }
>>   #endif /* CONFIG_STRICT_KERNEL_RWX */
>>   +#ifdef CONFIG_64BIT
>> +static void __init disable_pgtable_l4(void)
>> +{
>> +    pgtable_l4_enabled = false;
>> +    kernel_map.page_offset = PAGE_OFFSET_L3;
>> +    satp_mode = SATP_MODE_39;
>> +}
>> +
>> +/*
>> + * There is a simple way to determine if 4-level is supported by the
>> + * underlying hardware: establish 1:1 mapping in 4-level page table mode
>> + * then read SATP to see if the configuration was taken into account
>> + * meaning sv48 is supported.
>> + */
>> +static __init void set_satp_mode(void)
>> +{
>> +    u64 identity_satp, hw_satp;
>> +    uintptr_t set_satp_mode_pmd;
>> +
>> +    set_satp_mode_pmd = ((unsigned long)set_satp_mode) & PMD_MASK;
>> +    create_pgd_mapping(early_pg_dir,
>> +               set_satp_mode_pmd, (uintptr_t)early_pud,
>> +               PGDIR_SIZE, PAGE_TABLE);
>> +    create_pud_mapping(early_pud,
>> +               set_satp_mode_pmd, (uintptr_t)early_pmd,
>> +               PUD_SIZE, PAGE_TABLE);
>> +    /* Handle the case where set_satp_mode straddles 2 PMDs */
>> +    create_pmd_mapping(early_pmd,
>> +               set_satp_mode_pmd, set_satp_mode_pmd,
>> +               PMD_SIZE, PAGE_KERNEL_EXEC);
>> +    create_pmd_mapping(early_pmd,
>> +               set_satp_mode_pmd + PMD_SIZE,
>> +               set_satp_mode_pmd + PMD_SIZE,
>> +               PMD_SIZE, PAGE_KERNEL_EXEC);
>> +
>> +    identity_satp = PFN_DOWN((uintptr_t)&early_pg_dir) | satp_mode;
>> +
>> +    local_flush_tlb_all();
>> +    csr_write(CSR_SATP, identity_satp);
>> +    hw_satp = csr_swap(CSR_SATP, 0ULL);
>> +    local_flush_tlb_all();
>> +
>> +    if (hw_satp != identity_satp)
>> +        disable_pgtable_l4();
>> +
>> +    memset(early_pg_dir, 0, PAGE_SIZE);
>> +    memset(early_pud, 0, PAGE_SIZE);
>> +    memset(early_pmd, 0, PAGE_SIZE);
>> +}
>> +#endif
>> +
>>   /*
>>    * setup_vm() is called from head.S with MMU-off.
>>    *
>> @@ -557,10 +697,15 @@ static void __init create_fdt_early_page_table(pgd_t *pgdir, uintptr_t dtb_pa)
>>       uintptr_t pa = dtb_pa & ~(PMD_SIZE - 1);
>>         create_pgd_mapping(early_pg_dir, DTB_EARLY_BASE_VA,
>> -               IS_ENABLED(CONFIG_64BIT) ? (uintptr_t)early_dtb_pmd : pa,
>> +               IS_ENABLED(CONFIG_64BIT) ? early_dtb_pgd_next : pa,
>>                  PGDIR_SIZE,
>>                  IS_ENABLED(CONFIG_64BIT) ? PAGE_TABLE : PAGE_KERNEL);
>>   +    if (pgtable_l4_enabled) {
>> +        create_pud_mapping(early_dtb_pud, DTB_EARLY_BASE_VA,
>> +                   (uintptr_t)early_dtb_pmd, PUD_SIZE, PAGE_TABLE);
>> +    }
>> +
>>       if (IS_ENABLED(CONFIG_64BIT)) {
>>           create_pmd_mapping(early_dtb_pmd, DTB_EARLY_BASE_VA,
>>                      pa, PMD_SIZE, PAGE_KERNEL);
>> @@ -593,6 +738,8 @@ void pt_ops_set_early(void)
>>   #ifndef __PAGETABLE_PMD_FOLDED
>>       pt_ops.alloc_pmd = alloc_pmd_early;
>>       pt_ops.get_pmd_virt = get_pmd_virt_early;
>> +    pt_ops.alloc_pud = alloc_pud_early;
>> +    pt_ops.get_pud_virt = get_pud_virt_early;
>>   #endif
>>   }
>>   @@ -611,6 +758,8 @@ void pt_ops_set_fixmap(void)
>>   #ifndef __PAGETABLE_PMD_FOLDED
>>       pt_ops.alloc_pmd = kernel_mapping_pa_to_va((uintptr_t)alloc_pmd_fixmap);
>>       pt_ops.get_pmd_virt = kernel_mapping_pa_to_va((uintptr_t)get_pmd_virt_fixmap);
>> +    pt_ops.alloc_pud = kernel_mapping_pa_to_va((uintptr_t)alloc_pud_fixmap);
>> +    pt_ops.get_pud_virt = kernel_mapping_pa_to_va((uintptr_t)get_pud_virt_fixmap);
>>   #endif
>>   }
>>   @@ -625,6 +774,8 @@ void pt_ops_set_late(void)
>>   #ifndef __PAGETABLE_PMD_FOLDED
>>       pt_ops.alloc_pmd = alloc_pmd_late;
>>       pt_ops.get_pmd_virt = get_pmd_virt_late;
>> +    pt_ops.alloc_pud = alloc_pud_late;
>> +    pt_ops.get_pud_virt = get_pud_virt_late;
>>   #endif
>>   }
>>   @@ -633,6 +784,7 @@ asmlinkage void __init setup_vm(uintptr_t dtb_pa)
>>       pmd_t __maybe_unused fix_bmap_spmd, fix_bmap_epmd;
>>         kernel_map.virt_addr = KERNEL_LINK_ADDR;
>> +    kernel_map.page_offset = _AC(CONFIG_PAGE_OFFSET, UL);
>>     #ifdef CONFIG_XIP_KERNEL
>>       kernel_map.xiprom = (uintptr_t)CONFIG_XIP_PHYS_ADDR;
>> @@ -647,6 +799,11 @@ asmlinkage void __init setup_vm(uintptr_t dtb_pa)
>>       kernel_map.phys_addr = (uintptr_t)(&_start);
>>       kernel_map.size = (uintptr_t)(&_end) - kernel_map.phys_addr;
>>   #endif
>> +
>> +#if defined(CONFIG_64BIT) && !defined(CONFIG_XIP_KERNEL)
>> +    set_satp_mode();
>> +#endif
>> +
>>       kernel_map.va_pa_offset = PAGE_OFFSET - kernel_map.phys_addr;
>>       kernel_map.va_kernel_pa_offset = kernel_map.virt_addr - kernel_map.phys_addr;
>>   @@ -676,15 +833,21 @@ asmlinkage void __init setup_vm(uintptr_t dtb_pa)
>>         /* Setup early PGD for fixmap */
>>       create_pgd_mapping(early_pg_dir, FIXADDR_START,
>> -               (uintptr_t)fixmap_pgd_next, PGDIR_SIZE, PAGE_TABLE);
>> +               fixmap_pgd_next, PGDIR_SIZE, PAGE_TABLE);
>>     #ifndef __PAGETABLE_PMD_FOLDED
>> -    /* Setup fixmap PMD */
>> +    /* Setup fixmap PUD and PMD */
>> +    if (pgtable_l4_enabled)
>> +        create_pud_mapping(fixmap_pud, FIXADDR_START,
>> +                   (uintptr_t)fixmap_pmd, PUD_SIZE, PAGE_TABLE);
>>       create_pmd_mapping(fixmap_pmd, FIXADDR_START,
>>                  (uintptr_t)fixmap_pte, PMD_SIZE, PAGE_TABLE);
>>       /* Setup trampoline PGD and PMD */
>>       create_pgd_mapping(trampoline_pg_dir, kernel_map.virt_addr,
>> -               (uintptr_t)trampoline_pmd, PGDIR_SIZE, PAGE_TABLE);
>> +               trampoline_pgd_next, PGDIR_SIZE, PAGE_TABLE);
>> +    if (pgtable_l4_enabled)
>> +        create_pud_mapping(trampoline_pud, kernel_map.virt_addr,
>> +                   (uintptr_t)trampoline_pmd, PUD_SIZE, PAGE_TABLE);
>>   #ifdef CONFIG_XIP_KERNEL
>>       create_pmd_mapping(trampoline_pmd, kernel_map.virt_addr,
>>                  kernel_map.xiprom, PMD_SIZE, PAGE_KERNEL_EXEC);
>> @@ -712,7 +875,7 @@ asmlinkage void __init setup_vm(uintptr_t dtb_pa)
>>        * Bootime fixmap only can handle PMD_SIZE mapping. Thus, boot-ioremap
>>        * range can not span multiple pmds.
>>        */
>> -    BUILD_BUG_ON((__fix_to_virt(FIX_BTMAP_BEGIN) >> PMD_SHIFT)
>> +    BUG_ON((__fix_to_virt(FIX_BTMAP_BEGIN) >> PMD_SHIFT)
>>                != (__fix_to_virt(FIX_BTMAP_END) >> PMD_SHIFT));
>>     #ifndef __PAGETABLE_PMD_FOLDED
>> @@ -783,9 +946,10 @@ static void __init setup_vm_final(void)
>>       /* Clear fixmap PTE and PMD mappings */
>>       clear_fixmap(FIX_PTE);
>>       clear_fixmap(FIX_PMD);
>> +    clear_fixmap(FIX_PUD);
>>         /* Move to swapper page table */
>> -    csr_write(CSR_SATP, PFN_DOWN(__pa_symbol(swapper_pg_dir)) | SATP_MODE);
>> +    csr_write(CSR_SATP, PFN_DOWN(__pa_symbol(swapper_pg_dir)) | satp_mode);
>>       local_flush_tlb_all();
>>         pt_ops_set_late();
>> diff --git a/arch/riscv/mm/kasan_init.c b/arch/riscv/mm/kasan_init.c
>> index 1434a0225140..993f50571a3b 100644
>> --- a/arch/riscv/mm/kasan_init.c
>> +++ b/arch/riscv/mm/kasan_init.c
>> @@ -11,7 +11,29 @@
>>   #include <asm/fixmap.h>
>>   #include <asm/pgalloc.h>
>>   +/*
>> + * Kasan shadow region must lie at a fixed address across sv39, sv48 and sv57
>> + * which is right before the kernel.
>> + *
>> + * For sv39, the region is aligned on PGDIR_SIZE so we only need to populate
>> + * the page global directory with kasan_early_shadow_pmd.
>> + *
>> + * For sv48 and sv57, the region is not aligned on PGDIR_SIZE so the mapping
>> + * must be divided as follows:
>> + * - the first PGD entry, although incomplete, is populated with
>> + *   kasan_early_shadow_pud/p4d
>> + * - the PGD entries in the middle are populated with kasan_early_shadow_pud/p4d
>> + * - the last PGD entry is shared with the kernel mapping so populated at the
>> + *   lower levels pud/p4d
>> + *
>> + * In addition, when shallow populating a kasan region (for example vmalloc),
>> + * this region may also not be aligned on PGDIR size, so we must go down to the
>> + * pud level too.
>> + */
>> +
>>   extern pgd_t early_pg_dir[PTRS_PER_PGD];
>> +extern struct pt_alloc_ops _pt_ops __initdata;
>> +#define pt_ops    _pt_ops
>>     static void __init kasan_populate_pte(pmd_t *pmd, unsigned long vaddr, unsigned long end)
>>   {
>> @@ -35,15 +57,19 @@ static void __init kasan_populate_pte(pmd_t *pmd, unsigned long vaddr, unsigned
>>       set_pmd(pmd, pfn_pmd(PFN_DOWN(__pa(base_pte)), PAGE_TABLE));
>>   }
>>   -static void __init kasan_populate_pmd(pgd_t *pgd, unsigned long vaddr, unsigned long end)
>> +static void __init kasan_populate_pmd(pud_t *pud, unsigned long vaddr, unsigned long end)
>>   {
>>       phys_addr_t phys_addr;
>>       pmd_t *pmdp, *base_pmd;
>>       unsigned long next;
>>   -    base_pmd = (pmd_t *)pgd_page_vaddr(*pgd);
>> -    if (base_pmd == lm_alias(kasan_early_shadow_pmd))
>> +    if (pud_none(*pud)) {
>>           base_pmd = memblock_alloc(PTRS_PER_PMD * sizeof(pmd_t), PAGE_SIZE);
>> +    } else {
>> +        base_pmd = (pmd_t *)pud_pgtable(*pud);
>> +        if (base_pmd == lm_alias(kasan_early_shadow_pmd))
>> +            base_pmd = memblock_alloc(PTRS_PER_PMD * sizeof(pmd_t), PAGE_SIZE);
>> +    }
>>         pmdp = base_pmd + pmd_index(vaddr);
>>   @@ -67,9 +93,72 @@ static void __init kasan_populate_pmd(pgd_t *pgd, unsigned long vaddr, unsigned
>>        * it entirely, memblock could allocate a page at a physical address
>>        * where KASAN is not populated yet and then we'd get a page fault.
>>        */
>> -    set_pgd(pgd, pfn_pgd(PFN_DOWN(__pa(base_pmd)), PAGE_TABLE));
>> +    set_pud(pud, pfn_pud(PFN_DOWN(__pa(base_pmd)), PAGE_TABLE));
>> +}
>> +
>> +static void __init kasan_populate_pud(pgd_t *pgd,
>> +                      unsigned long vaddr, unsigned long end,
>> +                      bool early)
>> +{
>> +    phys_addr_t phys_addr;
>> +    pud_t *pudp, *base_pud;
>> +    unsigned long next;
>> +
>> +    if (early) {
>> +        /*
>> +         * We can't use pgd_page_vaddr here as it would return a linear
>> +         * mapping address but it is not mapped yet, but when populating
>> +         * early_pg_dir, we need the physical address and when populating
>> +         * swapper_pg_dir, we need the kernel virtual address so use
>> +         * pt_ops facility.
>> +         */
>> +        base_pud = pt_ops.get_pud_virt(pfn_to_phys(_pgd_pfn(*pgd)));
>> +    } else {
>> +        base_pud = (pud_t *)pgd_page_vaddr(*pgd);
>> +        if (base_pud == lm_alias(kasan_early_shadow_pud))
>> +            base_pud = memblock_alloc(PTRS_PER_PUD * sizeof(pud_t), PAGE_SIZE);
>> +    }
>> +
>> +    pudp = base_pud + pud_index(vaddr);
>> +
>> +    do {
>> +        next = pud_addr_end(vaddr, end);
>> +
>> +        if (pud_none(*pudp) && IS_ALIGNED(vaddr, PUD_SIZE) && (next - vaddr) >= PUD_SIZE) {
>> +            if (early) {
>> +                phys_addr = __pa(((uintptr_t)kasan_early_shadow_pmd));
>> +                set_pud(pudp, pfn_pud(PFN_DOWN(phys_addr), PAGE_TABLE));
>> +                continue;
>> +            } else {
>> +                phys_addr = memblock_phys_alloc(PUD_SIZE, PUD_SIZE);
>> +                if (phys_addr) {
>> +                    set_pud(pudp, pfn_pud(PFN_DOWN(phys_addr), PAGE_KERNEL));
>> +                    continue;
>> +                }
>> +            }
>> +        }
>> +
>> +        kasan_populate_pmd(pudp, vaddr, next);
>> +    } while (pudp++, vaddr = next, vaddr != end);
>> +
>> +    /*
>> +     * Wait for the whole PGD to be populated before setting the PGD in
>> +     * the page table, otherwise, if we did set the PGD before populating
>> +     * it entirely, memblock could allocate a page at a physical address
>> +     * where KASAN is not populated yet and then we'd get a page fault.
>> +     */
>> +    if (!early)
>> +        set_pgd(pgd, pfn_pgd(PFN_DOWN(__pa(base_pud)), PAGE_TABLE));
>>   }
>>   +#define kasan_early_shadow_pgd_next (pgtable_l4_enabled ?    \
>> +                (uintptr_t)kasan_early_shadow_pud : \
>> +                (uintptr_t)kasan_early_shadow_pmd)
>> +#define kasan_populate_pgd_next(pgdp, vaddr, next, early)            \
>> +        (pgtable_l4_enabled ?                        \
>> +            kasan_populate_pud(pgdp, vaddr, next, early) :        \
>> +            kasan_populate_pmd((pud_t *)pgdp, vaddr, next))
>> +
>>   static void __init kasan_populate_pgd(pgd_t *pgdp,
>>                         unsigned long vaddr, unsigned long end,
>>                         bool early)
>> @@ -102,7 +191,7 @@ static void __init kasan_populate_pgd(pgd_t *pgdp,
>>               }
>>           }
>>   -        kasan_populate_pmd(pgdp, vaddr, next);
>> +        kasan_populate_pgd_next(pgdp, vaddr, next, early);
>>       } while (pgdp++, vaddr = next, vaddr != end);
>>   }
>>   @@ -157,18 +246,54 @@ static void __init kasan_populate(void *start, void *end)
>>       memset(start, KASAN_SHADOW_INIT, end - start);
>>   }
>>   +static void __init kasan_shallow_populate_pud(pgd_t *pgdp,
>> +                          unsigned long vaddr, unsigned long end,
>> +                          bool kasan_populate)
>> +{
>> +    unsigned long next;
>> +    pud_t *pudp, *base_pud;
>> +    pmd_t *base_pmd;
>> +    bool is_kasan_pmd;
>> +
>> +    base_pud = (pud_t *)pgd_page_vaddr(*pgdp);
>> +    pudp = base_pud + pud_index(vaddr);
>> +
>> +    if (kasan_populate)
>> +        memcpy(base_pud, (void *)kasan_early_shadow_pgd_next,
>> +               sizeof(pud_t) * PTRS_PER_PUD);
>> +
>> +    do {
>> +        next = pud_addr_end(vaddr, end);
>> +        is_kasan_pmd = (pud_pgtable(*pudp) == lm_alias(kasan_early_shadow_pmd));
>> +
>> +        if (is_kasan_pmd) {
>> +            base_pmd = memblock_alloc(PAGE_SIZE, PAGE_SIZE);
>> +            set_pud(pudp, pfn_pud(PFN_DOWN(__pa(base_pmd)), PAGE_TABLE));
>> +        }
>> +    } while (pudp++, vaddr = next, vaddr != end);
>> +}
>> +
>>   static void __init kasan_shallow_populate_pgd(unsigned long vaddr, unsigned long end)
>>   {
>>       unsigned long next;
>>       void *p;
>>       pgd_t *pgd_k = pgd_offset_k(vaddr);
>> +    bool is_kasan_pgd_next;
>>         do {
>>           next = pgd_addr_end(vaddr, end);
>> -        if (pgd_page_vaddr(*pgd_k) == (unsigned long)lm_alias(kasan_early_shadow_pmd)) {
>> +        is_kasan_pgd_next = (pgd_page_vaddr(*pgd_k) ==
>> +                     (unsigned long)lm_alias(kasan_early_shadow_pgd_next));
>> +
>> +        if (is_kasan_pgd_next) {
>>               p = memblock_alloc(PAGE_SIZE, PAGE_SIZE);
>>               set_pgd(pgd_k, pfn_pgd(PFN_DOWN(__pa(p)), PAGE_TABLE));
>>           }
>> +
>> +        if (IS_ALIGNED(vaddr, PGDIR_SIZE) && (next - vaddr) >= PGDIR_SIZE)
>> +            continue;
>> +
>> +        kasan_shallow_populate_pud(pgd_k, vaddr, next, is_kasan_pgd_next);
>>       } while (pgd_k++, vaddr = next, vaddr != end);
>>   }
>
>
> @Qinglin: I can deal with sv57 kasan population if needs be as it is a bit tricky and I think it would save you quite some time :)

Thanks so much for you suggestion! And I want to give it a try firstly as I am now making new Sv57 patchset :) I will ask for your help when I meet any trouble, and thanks again!

Yours,
Qinglin

>
>
>>   diff --git a/drivers/firmware/efi/libstub/efi-stub.c b/drivers/firmware/efi/libstub/efi-stub.c
>> index 26e69788f27a..b3db5d91ed38 100644
>> --- a/drivers/firmware/efi/libstub/efi-stub.c
>> +++ b/drivers/firmware/efi/libstub/efi-stub.c
>> @@ -40,6 +40,8 @@
>>     #ifdef CONFIG_ARM64
>>   # define EFI_RT_VIRTUAL_LIMIT    DEFAULT_MAP_WINDOW_64
>> +#elif defined(CONFIG_RISCV)
>> +# define EFI_RT_VIRTUAL_LIMIT    TASK_SIZE_MIN
>>   #else
>>   # define EFI_RT_VIRTUAL_LIMIT    TASK_SIZE
>>   #endif