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Merge patch series "riscv: Memory Hot(Un)Plug support"

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Björn Töpel <bjorn@kernel.org> says:

From: Björn Töpel <bjorn@rivosinc.com>

================================================================
Memory Hot(Un)Plug support (and ZONE_DEVICE) for the RISC-V port
================================================================

Introduction
============

To quote "Documentation/admin-guide/mm/memory-hotplug.rst": "Memory
hot(un)plug allows for increasing and decreasing the size of physical
memory available to a machine at runtime."

This series adds memory hot(un)plugging, and ZONE_DEVICE support for
the RISC-V Linux port.

MM configuration
================

RISC-V MM has the following configuration:

 * Memory blocks are 128M, analogous to x86-64. It uses PMD
   ("hugepage") vmemmaps. From that follows that 2M (PMD) worth of
   vmemmap spans 32768 pages á 4K which gets us 128M.

 * The pageblock size is the minimum minimum virtio_mem size, and on
   RISC-V it's 2M (2^9 * 4K).

Implementation
==============

The PGD table on RISC-V is shared/copied between for all processes. To
avoid doing page table synchronization, the first patch (patch 1)
pre-allocated the PGD entries for vmemmap/direct map. By doing that
the init_mm PGD will be fixed at kernel init, and synchronization can
be avoided all together.

The following two patches (patch 2-3) does some preparations, followed
by the actual MHP implementation (patch 4-5). Then, MHP and virtio-mem
are enabled (patch 6-7), and finally ZONE_DEVICE support is added
(patch 8).

MHP and locking
===============

TL;DR: The MHP does not step on any toes, except for ptdump.
Additional locking is required for ptdump.

Long version: For v2 I spent some time digging into init_mm
synchronization/update. Here are my findings, and I'd love them to be
corrected if incorrect.

It's been a gnarly path...

The `init_mm` structure is a special mm (perhaps not a "real" one).
It's a "lazy context" that tracks kernel page table resources, e.g.,
the kernel page table (swapper_pg_dir), a kernel page_table_lock (more
about the usage below), mmap_lock, and such.

`init_mm` does not track/contain any VMAs. Having the `init_mm` is
convenient, so that the regular kernel page table walk/modify
functions can be used.

Now, `init_mm` being special means that the locking for kernel page
tables are special as well.

On RISC-V the PGD (top-level page table structure), similar to x86, is
shared (copied) with user processes. If the kernel PGD is modified, it
has to be synched to user-mode processes PGDs. This is avoided by
pre-populating the PGD, so it'll be fixed from boot.

The in-kernel pgd regions are documented in
`Documentation/arch/riscv/vm-layout.rst`.

The distinct regions are:
 * vmemmap
 * vmalloc/ioremap space
 * direct mapping of all physical memory
 * kasan
 * modules, BPF
 * kernel

Memory hotplug is the process of adding/removing memory to/from the
kernel.

Adding is done in two phases:
 1. Add the memory to the kernel
 2. Online memory, making it available to the page allocator.

Step 1 is partially architecture dependent, and updates the init_mm
page table:
 * Update the direct map page tables. The direct map is a linear map,
   representing all physical memory: `virt = phys + PAGE_OFFSET`
 * Add a `struct page` for each added page of memory. Update the
   vmemmap (virtual mapping to the `struct page`, so we can easily
   transform a kernel virtual address to a `struct page *` address.

From an MHP perspective, there are two regions of the PGD that are
updated:
 * vmemmap
 * direct mapping of all physical memory

The `struct mm_struct` has a couple of locks in play:
 * `spinlock_t page_table_lock` protects the page table, and some
    counters
 * `struct rw_semaphore mmap_lock` protect an mm's VMAs

Note again that `init_mm` does not contain any VMAs, but still uses
the mmap_lock in some places.

The `page_table_lock` was originally used to to protect all pages
tables, but more recently a split page table lock has been introduced.
The split lock has a per-table lock for the PTE and PMD tables. If
split lock is disabled, all tables are guarded by
`mm->page_table_lock` (for user processes). Split page table locks are
not used for init_mm.

MHP operations is typically synchronized using
`DEFINE_STATIC_PERCPU_RWSEM(mem_hotplug_lock)`.

Actors
------

The following non-MHP actors in the kernel traverses (read), and/or
modifies the kernel PGD.

 * `ptdump`

   Walks the entire `init_mm`, via `ptdump_walk_pgd()` with the
   `mmap_write_lock(init_mm)` taken.

   Observation: ptdump can race with MHP, and needs additional locking
   to avoid crashes/races.

 * `set_direct_*` / `arch/riscv/mm/pageattr.c`

   The `set_direct_*` functionality is used to "synchronize" the
   direct map to other kernel mappings, e.g. modules/kernel text. The
   direct map is using "as large huge table mappings as possible",
   which means that the `set_direct_*` might need to split the direct
   map.

  The `set_direct_*` functions operates with the
  `mmap_write_lock(init_mm)` taken.

  Observation: `set_direct_*` uses the direct map, but will never
  modify the same entry as MHP. If there is a mapping, that entry will
  never race with MHP. Further, MHP acts when memory is offline.

 * HVO / `mm/hugetlb_vmemmap`

   HVO optimizes the backing `struct page` for hugetlb pages, which
   means changing the "vmemmap" region. HVO can split (merge?) a
   vmemmap pmd. However, it will never race with MHP, since HVO only
   operates at online memory. HVO cannot touch memory being MHP added
   or removed.

 * `apply_to_page_range`

   Walks a range, creates pages and applies a callback (setting
   permissions) for the page.

   When creating a table, it might use `int __pte_alloc_kernel(pmd_t
   *pmd)` which takes the `init_mm.page_table_lock` to synchronize pmd
   populate.

   Used by: `mm/vmalloc.c` and `mm/kasan/shadow.c`. The KASAN callback
   takes the `init_mm.page_table_lock` to synchronize pte creation.

   Observations: `apply_to_page_range` applies to the "vmalloc/ioremap
   space" region, and "kasan" region. *Not* affected by MHP.

 * `apply_to_existing_page_range`

   Walks a range, applies a callback (setting permissions) for the
   page (no page creation).

   Used by: `kernel/bpf/arena.c` and `mm/kasan/shadow.c`. The KASAN
   callback takes the `init_mm.page_table_lock` to synchronize pte
   creation. *Not* affected by MHP regions.

 * `apply_to_existing_page_range` applies to the "vmalloc/ioremap
   space" region, and "kasan" region. *Not* affected by MHP regions.

 *  `ioremap_page_range` and `vmap_page_range`

    Uses the same internal function, and might create table entries at
    the "vmalloc/ioremap space" region. Can call
    `__pte_alloc_kernel()` which takes the `init_mm.page_table_lock`
    synchronizing pmd populate in the region. *Not* affected by MHP
    regions.

Summary:
  * MHP add will never modify the same page table entries, as any of
    the other actors.
  * MHP remove is done when memory is offlined, and will not clash
    with any of the actors.
  * Functions that walk the entire kernel page table need
    synchronization

  * It's sufficient to add the MHP lock ptdump.

Testing
=======

This series adds basic DT supported hotplugging. There is a QEMU
series enabling MHP for the RISC-V "virt" machine here: [1]

ACPI/MSI support is still in the making for RISC-V, and prior proper
(ACPI) PCI MSI support lands [2] and NUMA SRAT support [3], it hard to
try it out.

I've prepared a QEMU branch with proper ACPI GED/PC-DIMM support [4],
and a this series with the required prerequisites [5] (AIA, ACPI AIA
MADT, ACPI NUMA SRAT).

To test with virtio-mem, e.g.:
  | qemu-system-riscv64 \
  |     -machine virt,aia=aplic-imsic \
  |     -cpu rv64,v=true,vlen=256,elen=64,h=true,zbkb=on,zbkc=on,zbkx=on,zkr=on,zkt=on,svinval=on,svnapot=on,svpbmt=on \
  |     -nodefaults \
  |     -nographic -smp 8 -kernel rv64-u-boot.bin \
  |     -drive file=rootfs.img,format=raw,if=virtio \
  |     -device virtio-rng-pci \
  |     -m 16G,slots=3,maxmem=32G \
  |     -object memory-backend-ram,id=mem0,size=16G \
  |     -numa node,nodeid=0,memdev=mem0 \
  |     -serial chardev:char0 \
  |     -mon chardev=char0,mode=readline \
  |     -chardev stdio,mux=on,id=char0 \
  |     -device pci-serial,id=serial0,chardev=char0 \
  |     -object memory-backend-ram,id=vmem0,size=2G \
  |     -device virtio-mem-pci,id=vm0,memdev=vmem0,node=0

where "rv64-u-boot.bin" is U-boot with EFI/ACPI-support (use [6] if
you're lazy).

In the QEMU monitor:
  | (qemu) info memory-devices
  | (qemu) qom-set vm0 requested-size 1G

...to test DAX/KMEM, use the follow QEMU parameters:
  |  -object memory-backend-file,id=mem1,share=on,mem-path=virtio_pmem.img,size=4G \
  |  -device virtio-pmem-pci,memdev=mem1,id=nv1

and the regular ndctl/daxctl dance.

If you're brave to try the ACPI branch, add "acpi=on" to "-machine
virt", and test PC-DIMM MHP (in addition to virtio-{p},mem):

In the QEMU monitor:
  | (qemu) object_add memory-backend-ram,id=mem1,size=1G
  | (qemu) device_add pc-dimm,id=dimm1,memdev=mem1

You can also try hot-remove with some QEMU options, say:
  | -object memory-backend-file,id=mem-1,size=256M,mem-path=/pagesize-2MB
  | -device pc-dimm,id=mem1,memdev=mem-1
  | -object memory-backend-file,id=mem-2,size=1G,mem-path=/pagesize-1GB
  | -device pc-dimm,id=mem2,memdev=mem-2
  | -object memory-backend-file,id=mem-3,size=256M,mem-path=/pagesize-2MB
  | -device pc-dimm,id=mem3,memdev=mem-3

Remove "acpi=on" to run with DT.

Thanks to Alex, Andrew, David, and Oscar for all
comments/tests/fixups.

References
==========

[1] https://lore.kernel.org/qemu-devel/20240521105635.795211-1-bjorn@kernel.org/
[2] https://lore.kernel.org/linux-riscv/20240501121742.1215792-1-sunilvl@ventanamicro.com/
[3] https://lore.kernel.org/linux-riscv/cover.1713778236.git.haibo1.xu@intel.com/
[4] https://github.com/bjoto/qemu/commits/virtio-mem-pc-dimm-mhp-acpi-v2/
[5] https://github.com/bjoto/linux/commits/mhp-v4-acpi
[6] https://github.com/bjoto/riscv-rootfs-utils/tree/acpi

* b4-shazam-merge:
  riscv: Enable DAX VMEMMAP optimization
  riscv: mm: Add support for ZONE_DEVICE
  virtio-mem: Enable virtio-mem for RISC-V
  riscv: Enable memory hotplugging for RISC-V
  riscv: mm: Take memory hotplug read-lock during kernel page table dump
  riscv: mm: Add memory hotplugging support
  riscv: mm: Add pfn_to_kaddr() implementation
  riscv: mm: Refactor create_linear_mapping_range() for memory hot add
  riscv: mm: Change attribute from __init to __meminit for page functions
  riscv: mm: Pre-allocate vmemmap/direct map/kasan PGD entries
  riscv: mm: Properly forward vmemmap_populate() altmap parameter

Link: https://lore.kernel.org/r/20240605114100.315918-1-bjorn@kernel.org
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
This commit is contained in:
Palmer Dabbelt
2024-06-26 08:43:07 -07:00
parent d6ecd18893 4705c1571a
commit 60a6707f58
10 changed files with 364 additions and 46 deletions
Download Patch File Download Diff File Expand all files Collapse all files
arch/riscv/Kconfig
+5
View File
@@ -16,6 +16,8 @@ config RISCV
select ACPI_REDUCED_HARDWARE_ONLY if ACPI
select ARCH_DMA_DEFAULT_COHERENT
select ARCH_ENABLE_HUGEPAGE_MIGRATION if HUGETLB_PAGE && MIGRATION
select ARCH_ENABLE_MEMORY_HOTPLUG if SPARSEMEM_VMEMMAP
select ARCH_ENABLE_MEMORY_HOTREMOVE if MEMORY_HOTPLUG
select ARCH_ENABLE_SPLIT_PMD_PTLOCK if PGTABLE_LEVELS > 2
select ARCH_ENABLE_THP_MIGRATION if TRANSPARENT_HUGEPAGE
select ARCH_HAS_BINFMT_FLAT
@@ -35,6 +37,7 @@ config RISCV
select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
select ARCH_HAS_PMEM_API
select ARCH_HAS_PREPARE_SYNC_CORE_CMD
select ARCH_HAS_PTE_DEVMAP if 64BIT && MMU
select ARCH_HAS_PTE_SPECIAL
select ARCH_HAS_SET_DIRECT_MAP if MMU
select ARCH_HAS_SET_MEMORY if MMU
@@ -46,6 +49,7 @@ config RISCV
select ARCH_HAS_UBSAN
select ARCH_HAS_VDSO_DATA
select ARCH_KEEP_MEMBLOCK if ACPI
select ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE if 64BIT && MMU
select ARCH_OPTIONAL_KERNEL_RWX if ARCH_HAS_STRICT_KERNEL_RWX
select ARCH_OPTIONAL_KERNEL_RWX_DEFAULT
select ARCH_STACKWALK
@@ -69,6 +73,7 @@ config RISCV
select ARCH_WANT_GENERAL_HUGETLB if !RISCV_ISA_SVNAPOT
select ARCH_WANT_HUGE_PMD_SHARE if 64BIT
select ARCH_WANT_LD_ORPHAN_WARN if !XIP_KERNEL
select ARCH_WANT_OPTIMIZE_DAX_VMEMMAP
select ARCH_WANT_OPTIMIZE_HUGETLB_VMEMMAP
select ARCH_WANTS_NO_INSTR
select ARCH_WANTS_THP_SWAP if HAVE_ARCH_TRANSPARENT_HUGEPAGE
arch/riscv/include/asm/kasan.h
+2 -2
View File
@@ -6,8 +6,6 @@
#ifndef __ASSEMBLY__
#ifdef CONFIG_KASAN
/*
* The following comment was copied from arm64:
* KASAN_SHADOW_START: beginning of the kernel virtual addresses.
@@ -34,6 +32,8 @@
*/
#define KASAN_SHADOW_START ((KASAN_SHADOW_END - KASAN_SHADOW_SIZE) & PGDIR_MASK)
#define KASAN_SHADOW_END MODULES_LOWEST_VADDR
#ifdef CONFIG_KASAN
#define KASAN_SHADOW_OFFSET _AC(CONFIG_KASAN_SHADOW_OFFSET, UL)
void kasan_init(void);
arch/riscv/include/asm/mmu.h
+2 -2
View File
@@ -31,8 +31,8 @@ typedef struct {
#define cntx2asid(cntx) ((cntx) & SATP_ASID_MASK)
#define cntx2version(cntx) ((cntx) & ~SATP_ASID_MASK)
void __init create_pgd_mapping(pgd_t *pgdp, uintptr_t va, phys_addr_t pa,
phys_addr_t sz, pgprot_t prot);
void __meminit create_pgd_mapping(pgd_t *pgdp, uintptr_t va, phys_addr_t pa, phys_addr_t sz,
pgprot_t prot);
#endif /* __ASSEMBLY__ */
#endif /* _ASM_RISCV_MMU_H */
arch/riscv/include/asm/page.h
+5
View File
@@ -188,6 +188,11 @@ extern phys_addr_t __phys_addr_symbol(unsigned long x);
unsigned long kaslr_offset(void);
static __always_inline void *pfn_to_kaddr(unsigned long pfn)
{
return __va(pfn << PAGE_SHIFT);
}
#endif /* __ASSEMBLY__ */
#define virt_addr_valid(vaddr) ({ \
arch/riscv/include/asm/pgtable-64.h
+20
View File
@@ -398,4 +398,24 @@ static inline struct page *pgd_page(pgd_t pgd)
#define p4d_offset p4d_offset
p4d_t *p4d_offset(pgd_t *pgd, unsigned long address);
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
static inline int pte_devmap(pte_t pte);
static inline pte_t pmd_pte(pmd_t pmd);
static inline int pmd_devmap(pmd_t pmd)
{
return pte_devmap(pmd_pte(pmd));
}
static inline int pud_devmap(pud_t pud)
{
return 0;
}
static inline int pgd_devmap(pgd_t pgd)
{
return 0;
}
#endif
#endif /* _ASM_RISCV_PGTABLE_64_H */
arch/riscv/include/asm/pgtable-bits.h
+1
View File
@@ -19,6 +19,7 @@
#define _PAGE_SOFT (3 << 8) /* Reserved for software */
#define _PAGE_SPECIAL (1 << 8) /* RSW: 0x1 */
#define _PAGE_DEVMAP (1 << 9) /* RSW, devmap */
#define _PAGE_TABLE _PAGE_PRESENT
/*
arch/riscv/include/asm/pgtable.h
+18 -1
View File
@@ -165,7 +165,7 @@ struct pt_alloc_ops {
#endif
};
extern struct pt_alloc_ops pt_ops __initdata;
extern struct pt_alloc_ops pt_ops __meminitdata;
#ifdef CONFIG_MMU
/* Number of PGD entries that a user-mode program can use */
@@ -403,6 +403,13 @@ static inline int pte_special(pte_t pte)
return pte_val(pte) & _PAGE_SPECIAL;
}
#ifdef CONFIG_ARCH_HAS_PTE_DEVMAP
static inline int pte_devmap(pte_t pte)
{
return pte_val(pte) & _PAGE_DEVMAP;
}
#endif
/* static inline pte_t pte_rdprotect(pte_t pte) */
static inline pte_t pte_wrprotect(pte_t pte)
@@ -444,6 +451,11 @@ static inline pte_t pte_mkspecial(pte_t pte)
return __pte(pte_val(pte) | _PAGE_SPECIAL);
}
static inline pte_t pte_mkdevmap(pte_t pte)
{
return __pte(pte_val(pte) | _PAGE_DEVMAP);
}
static inline pte_t pte_mkhuge(pte_t pte)
{
return pte;
@@ -734,6 +746,11 @@ static inline pmd_t pmd_mkdirty(pmd_t pmd)
return pte_pmd(pte_mkdirty(pmd_pte(pmd)));
}
static inline pmd_t pmd_mkdevmap(pmd_t pmd)
{
return pte_pmd(pte_mkdevmap(pmd_pte(pmd)));
}
static inline void set_pmd_at(struct mm_struct *mm, unsigned long addr,
pmd_t *pmdp, pmd_t pmd)
{
arch/riscv/mm/init.c
+307 -40
View File
@@ -28,6 +28,7 @@
#include <asm/fixmap.h>
#include <asm/io.h>
#include <asm/kasan.h>
#include <asm/numa.h>
#include <asm/pgtable.h>
#include <asm/sections.h>
@@ -295,7 +296,7 @@ static void __init setup_bootmem(void)
}
#ifdef CONFIG_MMU
struct pt_alloc_ops pt_ops __initdata;
struct pt_alloc_ops pt_ops __meminitdata;
pgd_t swapper_pg_dir[PTRS_PER_PGD] __page_aligned_bss;
pgd_t trampoline_pg_dir[PTRS_PER_PGD] __page_aligned_bss;
@@ -357,7 +358,7 @@ static inline pte_t *__init get_pte_virt_fixmap(phys_addr_t pa)
return (pte_t *)set_fixmap_offset(FIX_PTE, pa);
}
static inline pte_t *__init get_pte_virt_late(phys_addr_t pa)
static inline pte_t *__meminit get_pte_virt_late(phys_addr_t pa)
{
return (pte_t *) __va(pa);
}
@@ -376,7 +377,7 @@ static inline phys_addr_t __init alloc_pte_fixmap(uintptr_t va)
return memblock_phys_alloc(PAGE_SIZE, PAGE_SIZE);
}
static phys_addr_t __init alloc_pte_late(uintptr_t va)
static phys_addr_t __meminit alloc_pte_late(uintptr_t va)
{
struct ptdesc *ptdesc = pagetable_alloc(GFP_KERNEL & ~__GFP_HIGHMEM, 0);
@@ -384,9 +385,8 @@ static phys_addr_t __init alloc_pte_late(uintptr_t va)
return __pa((pte_t *)ptdesc_address(ptdesc));
}
static void __init create_pte_mapping(pte_t *ptep,
uintptr_t va, phys_addr_t pa,
phys_addr_t sz, pgprot_t prot)
static void __meminit create_pte_mapping(pte_t *ptep, uintptr_t va, phys_addr_t pa, phys_addr_t sz,
pgprot_t prot)
{
uintptr_t pte_idx = pte_index(va);
@@ -440,7 +440,7 @@ static pmd_t *__init get_pmd_virt_fixmap(phys_addr_t pa)
return (pmd_t *)set_fixmap_offset(FIX_PMD, pa);
}
static pmd_t *__init get_pmd_virt_late(phys_addr_t pa)
static pmd_t *__meminit get_pmd_virt_late(phys_addr_t pa)
{
return (pmd_t *) __va(pa);
}
@@ -457,7 +457,7 @@ static phys_addr_t __init alloc_pmd_fixmap(uintptr_t va)
return memblock_phys_alloc(PAGE_SIZE, PAGE_SIZE);
}
static phys_addr_t __init alloc_pmd_late(uintptr_t va)
static phys_addr_t __meminit alloc_pmd_late(uintptr_t va)
{
struct ptdesc *ptdesc = pagetable_alloc(GFP_KERNEL & ~__GFP_HIGHMEM, 0);
@@ -465,9 +465,9 @@ static phys_addr_t __init alloc_pmd_late(uintptr_t va)
return __pa((pmd_t *)ptdesc_address(ptdesc));
}
static void __init create_pmd_mapping(pmd_t *pmdp,
uintptr_t va, phys_addr_t pa,
phys_addr_t sz, pgprot_t prot)
static void __meminit create_pmd_mapping(pmd_t *pmdp,
uintptr_t va, phys_addr_t pa,
phys_addr_t sz, pgprot_t prot)
{
pte_t *ptep;
phys_addr_t pte_phys;
@@ -503,7 +503,7 @@ static pud_t *__init get_pud_virt_fixmap(phys_addr_t pa)
return (pud_t *)set_fixmap_offset(FIX_PUD, pa);
}
static pud_t *__init get_pud_virt_late(phys_addr_t pa)
static pud_t *__meminit get_pud_virt_late(phys_addr_t pa)
{
return (pud_t *)__va(pa);
}
@@ -521,7 +521,7 @@ 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)
static phys_addr_t __meminit alloc_pud_late(uintptr_t va)
{
unsigned long vaddr;
@@ -541,7 +541,7 @@ static p4d_t *__init get_p4d_virt_fixmap(phys_addr_t pa)
return (p4d_t *)set_fixmap_offset(FIX_P4D, pa);
}
static p4d_t *__init get_p4d_virt_late(phys_addr_t pa)
static p4d_t *__meminit get_p4d_virt_late(phys_addr_t pa)
{
return (p4d_t *)__va(pa);
}
@@ -559,7 +559,7 @@ static phys_addr_t __init alloc_p4d_fixmap(uintptr_t va)
return memblock_phys_alloc(PAGE_SIZE, PAGE_SIZE);
}
static phys_addr_t alloc_p4d_late(uintptr_t va)
static phys_addr_t __meminit alloc_p4d_late(uintptr_t va)
{
unsigned long vaddr;
@@ -568,9 +568,8 @@ static phys_addr_t alloc_p4d_late(uintptr_t va)
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)
static void __meminit 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;
@@ -595,9 +594,8 @@ static void __init create_pud_mapping(pud_t *pudp,
create_pmd_mapping(nextp, va, pa, sz, prot);
}
static void __init create_p4d_mapping(p4d_t *p4dp,
uintptr_t va, phys_addr_t pa,
phys_addr_t sz, pgprot_t prot)
static void __meminit create_p4d_mapping(p4d_t *p4dp, uintptr_t va, phys_addr_t pa, phys_addr_t sz,
pgprot_t prot)
{
pud_t *nextp;
phys_addr_t next_phys;
@@ -653,9 +651,8 @@ static void __init create_p4d_mapping(p4d_t *p4dp,
#define create_pmd_mapping(__pmdp, __va, __pa, __sz, __prot) do {} while(0)
#endif /* __PAGETABLE_PMD_FOLDED */
void __init create_pgd_mapping(pgd_t *pgdp,
uintptr_t va, phys_addr_t pa,
phys_addr_t sz, pgprot_t prot)
void __meminit create_pgd_mapping(pgd_t *pgdp, uintptr_t va, phys_addr_t pa, phys_addr_t sz,
pgprot_t prot)
{
pgd_next_t *nextp;
phys_addr_t next_phys;
@@ -680,8 +677,7 @@ void __init create_pgd_mapping(pgd_t *pgdp,
create_pgd_next_mapping(nextp, va, pa, sz, prot);
}
static uintptr_t __init best_map_size(phys_addr_t pa, uintptr_t va,
phys_addr_t size)
static uintptr_t __meminit best_map_size(phys_addr_t pa, uintptr_t va, phys_addr_t size)
{
if (debug_pagealloc_enabled())
return PAGE_SIZE;
@@ -717,7 +713,7 @@ asmlinkage void __init __copy_data(void)
#endif
#ifdef CONFIG_STRICT_KERNEL_RWX
static __init pgprot_t pgprot_from_va(uintptr_t va)
static __meminit pgprot_t pgprot_from_va(uintptr_t va)
{
if (is_va_kernel_text(va))
return PAGE_KERNEL_READ_EXEC;
@@ -742,7 +738,7 @@ void mark_rodata_ro(void)
set_memory_ro);
}
#else
static __init pgprot_t pgprot_from_va(uintptr_t va)
static __meminit pgprot_t pgprot_from_va(uintptr_t va)
{
if (IS_ENABLED(CONFIG_64BIT) && !is_kernel_mapping(va))
return PAGE_KERNEL;
@@ -1234,9 +1230,8 @@ asmlinkage void __init setup_vm(uintptr_t dtb_pa)
pt_ops_set_fixmap();
}
static void __init create_linear_mapping_range(phys_addr_t start,
phys_addr_t end,
uintptr_t fixed_map_size)
static void __meminit create_linear_mapping_range(phys_addr_t start, phys_addr_t end,
uintptr_t fixed_map_size, const pgprot_t *pgprot)
{
phys_addr_t pa;
uintptr_t va, map_size;
@@ -1247,7 +1242,7 @@ static void __init create_linear_mapping_range(phys_addr_t start,
best_map_size(pa, va, end - pa);
create_pgd_mapping(swapper_pg_dir, va, pa, map_size,
pgprot_from_va(va));
pgprot ? *pgprot : pgprot_from_va(va));
}
}
@@ -1291,22 +1286,19 @@ static void __init create_linear_mapping_page_table(void)
if (end >= __pa(PAGE_OFFSET) + memory_limit)
end = __pa(PAGE_OFFSET) + memory_limit;
create_linear_mapping_range(start, end, 0);
create_linear_mapping_range(start, end, 0, NULL);
}
#ifdef CONFIG_STRICT_KERNEL_RWX
create_linear_mapping_range(ktext_start, ktext_start + ktext_size, 0);
create_linear_mapping_range(krodata_start,
krodata_start + krodata_size, 0);
create_linear_mapping_range(ktext_start, ktext_start + ktext_size, 0, NULL);
create_linear_mapping_range(krodata_start, krodata_start + krodata_size, 0, NULL);
memblock_clear_nomap(ktext_start, ktext_size);
memblock_clear_nomap(krodata_start, krodata_size);
#endif
#ifdef CONFIG_KFENCE
create_linear_mapping_range(kfence_pool,
kfence_pool + KFENCE_POOL_SIZE,
PAGE_SIZE);
create_linear_mapping_range(kfence_pool, kfence_pool + KFENCE_POOL_SIZE, PAGE_SIZE, NULL);
memblock_clear_nomap(kfence_pool, KFENCE_POOL_SIZE);
#endif
@@ -1438,7 +1430,7 @@ int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node,
* memory hotplug, we are not able to update all the page tables with
* the new PMDs.
*/
return vmemmap_populate_hugepages(start, end, node, NULL);
return vmemmap_populate_hugepages(start, end, node, altmap);
}
#endif
@@ -1492,11 +1484,19 @@ failed:
panic("Failed to pre-allocate %s pages for %s area\n", lvl, area);
}
#define PAGE_END KASAN_SHADOW_START
void __init pgtable_cache_init(void)
{
preallocate_pgd_pages_range(VMALLOC_START, VMALLOC_END, "vmalloc");
if (IS_ENABLED(CONFIG_MODULES))
preallocate_pgd_pages_range(MODULES_VADDR, MODULES_END, "bpf/modules");
if (IS_ENABLED(CONFIG_MEMORY_HOTPLUG)) {
preallocate_pgd_pages_range(VMEMMAP_START, VMEMMAP_END, "vmemmap");
preallocate_pgd_pages_range(PAGE_OFFSET, PAGE_END, "direct map");
if (IS_ENABLED(CONFIG_KASAN))
preallocate_pgd_pages_range(KASAN_SHADOW_START, KASAN_SHADOW_END, "kasan");
}
}
#endif
@@ -1533,3 +1533,270 @@ struct execmem_info __init *execmem_arch_setup(void)
}
#endif /* CONFIG_MMU */
#endif /* CONFIG_EXECMEM */
#ifdef CONFIG_MEMORY_HOTPLUG
static void __meminit free_pte_table(pte_t *pte_start, pmd_t *pmd)
{
struct page *page = pmd_page(*pmd);
struct ptdesc *ptdesc = page_ptdesc(page);
pte_t *pte;
int i;
for (i = 0; i < PTRS_PER_PTE; i++) {
pte = pte_start + i;
if (!pte_none(*pte))
return;
}
pagetable_pte_dtor(ptdesc);
if (PageReserved(page))
free_reserved_page(page);
else
pagetable_free(ptdesc);
pmd_clear(pmd);
}
static void __meminit free_pmd_table(pmd_t *pmd_start, pud_t *pud)
{
struct page *page = pud_page(*pud);
struct ptdesc *ptdesc = page_ptdesc(page);
pmd_t *pmd;
int i;
for (i = 0; i < PTRS_PER_PMD; i++) {
pmd = pmd_start + i;
if (!pmd_none(*pmd))
return;
}
pagetable_pmd_dtor(ptdesc);
if (PageReserved(page))
free_reserved_page(page);
else
pagetable_free(ptdesc);
pud_clear(pud);
}
static void __meminit free_pud_table(pud_t *pud_start, p4d_t *p4d)
{
struct page *page = p4d_page(*p4d);
pud_t *pud;
int i;
for (i = 0; i < PTRS_PER_PUD; i++) {
pud = pud_start + i;
if (!pud_none(*pud))
return;
}
if (PageReserved(page))
free_reserved_page(page);
else
free_pages((unsigned long)page_address(page), 0);
p4d_clear(p4d);
}
static void __meminit free_vmemmap_storage(struct page *page, size_t size,
struct vmem_altmap *altmap)
{
int order = get_order(size);
if (altmap) {
vmem_altmap_free(altmap, size >> PAGE_SHIFT);
return;
}
if (PageReserved(page)) {
unsigned int nr_pages = 1 << order;
while (nr_pages--)
free_reserved_page(page++);
return;
}
free_pages((unsigned long)page_address(page), order);
}
static void __meminit remove_pte_mapping(pte_t *pte_base, unsigned long addr, unsigned long end,
bool is_vmemmap, struct vmem_altmap *altmap)
{
unsigned long next;
pte_t *ptep, pte;
for (; addr < end; addr = next) {
next = (addr + PAGE_SIZE) & PAGE_MASK;
if (next > end)
next = end;
ptep = pte_base + pte_index(addr);
pte = ptep_get(ptep);
if (!pte_present(*ptep))
continue;
pte_clear(&init_mm, addr, ptep);
if (is_vmemmap)
free_vmemmap_storage(pte_page(pte), PAGE_SIZE, altmap);
}
}
static void __meminit remove_pmd_mapping(pmd_t *pmd_base, unsigned long addr, unsigned long end,
bool is_vmemmap, struct vmem_altmap *altmap)
{
unsigned long next;
pte_t *pte_base;
pmd_t *pmdp, pmd;
for (; addr < end; addr = next) {
next = pmd_addr_end(addr, end);
pmdp = pmd_base + pmd_index(addr);
pmd = pmdp_get(pmdp);
if (!pmd_present(pmd))
continue;
if (pmd_leaf(pmd)) {
pmd_clear(pmdp);
if (is_vmemmap)
free_vmemmap_storage(pmd_page(pmd), PMD_SIZE, altmap);
continue;
}
pte_base = (pte_t *)pmd_page_vaddr(*pmdp);
remove_pte_mapping(pte_base, addr, next, is_vmemmap, altmap);
free_pte_table(pte_base, pmdp);
}
}
static void __meminit remove_pud_mapping(pud_t *pud_base, unsigned long addr, unsigned long end,
bool is_vmemmap, struct vmem_altmap *altmap)
{
unsigned long next;
pud_t *pudp, pud;
pmd_t *pmd_base;
for (; addr < end; addr = next) {
next = pud_addr_end(addr, end);
pudp = pud_base + pud_index(addr);
pud = pudp_get(pudp);
if (!pud_present(pud))
continue;
if (pud_leaf(pud)) {
if (pgtable_l4_enabled) {
pud_clear(pudp);
if (is_vmemmap)
free_vmemmap_storage(pud_page(pud), PUD_SIZE, altmap);
}
continue;
}
pmd_base = pmd_offset(pudp, 0);
remove_pmd_mapping(pmd_base, addr, next, is_vmemmap, altmap);
if (pgtable_l4_enabled)
free_pmd_table(pmd_base, pudp);
}
}
static void __meminit remove_p4d_mapping(p4d_t *p4d_base, unsigned long addr, unsigned long end,
bool is_vmemmap, struct vmem_altmap *altmap)
{
unsigned long next;
p4d_t *p4dp, p4d;
pud_t *pud_base;
for (; addr < end; addr = next) {
next = p4d_addr_end(addr, end);
p4dp = p4d_base + p4d_index(addr);
p4d = p4dp_get(p4dp);
if (!p4d_present(p4d))
continue;
if (p4d_leaf(p4d)) {
if (pgtable_l5_enabled) {
p4d_clear(p4dp);
if (is_vmemmap)
free_vmemmap_storage(p4d_page(p4d), P4D_SIZE, altmap);
}
continue;
}
pud_base = pud_offset(p4dp, 0);
remove_pud_mapping(pud_base, addr, next, is_vmemmap, altmap);
if (pgtable_l5_enabled)
free_pud_table(pud_base, p4dp);
}
}
static void __meminit remove_pgd_mapping(unsigned long va, unsigned long end, bool is_vmemmap,
struct vmem_altmap *altmap)
{
unsigned long addr, next;
p4d_t *p4d_base;
pgd_t *pgd;
for (addr = va; addr < end; addr = next) {
next = pgd_addr_end(addr, end);
pgd = pgd_offset_k(addr);
if (!pgd_present(*pgd))
continue;
if (pgd_leaf(*pgd))
continue;
p4d_base = p4d_offset(pgd, 0);
remove_p4d_mapping(p4d_base, addr, next, is_vmemmap, altmap);
}
flush_tlb_all();
}
static void __meminit remove_linear_mapping(phys_addr_t start, u64 size)
{
unsigned long va = (unsigned long)__va(start);
unsigned long end = (unsigned long)__va(start + size);
remove_pgd_mapping(va, end, false, NULL);
}
struct range arch_get_mappable_range(void)
{
struct range mhp_range;
mhp_range.start = __pa(PAGE_OFFSET);
mhp_range.end = __pa(PAGE_END - 1);
return mhp_range;
}
int __ref arch_add_memory(int nid, u64 start, u64 size, struct mhp_params *params)
{
int ret = 0;
create_linear_mapping_range(start, start + size, 0, &params->pgprot);
ret = __add_pages(nid, start >> PAGE_SHIFT, size >> PAGE_SHIFT, params);
if (ret) {
remove_linear_mapping(start, size);
goto out;
}
max_pfn = PFN_UP(start + size);
max_low_pfn = max_pfn;
out:
flush_tlb_all();
return ret;
}
void __ref arch_remove_memory(u64 start, u64 size, struct vmem_altmap *altmap)
{
__remove_pages(start >> PAGE_SHIFT, size >> PAGE_SHIFT, altmap);
remove_linear_mapping(start, size);
flush_tlb_all();
}
void __ref vmemmap_free(unsigned long start, unsigned long end, struct vmem_altmap *altmap)
{
remove_pgd_mapping(start, end, true, altmap);
}
#endif /* CONFIG_MEMORY_HOTPLUG */
arch/riscv/mm/ptdump.c
+3
View File
@@ -6,6 +6,7 @@
#include <linux/efi.h>
#include <linux/init.h>
#include <linux/debugfs.h>
#include <linux/memory_hotplug.h>
#include <linux/seq_file.h>
#include <linux/ptdump.h>
@@ -370,7 +371,9 @@ bool ptdump_check_wx(void)
static int ptdump_show(struct seq_file *m, void *v)
{
get_online_mems();
ptdump_walk(m, m->private);
put_online_mems();
return 0;
}
drivers/virtio/Kconfig
+1 -1
View File
@@ -122,7 +122,7 @@ config VIRTIO_BALLOON
config VIRTIO_MEM
tristate "Virtio mem driver"
depends on X86_64 || ARM64
depends on X86_64 || ARM64 || RISCV
depends on VIRTIO
depends on MEMORY_HOTPLUG
depends on MEMORY_HOTREMOVE