git: de09dcebd720 - main - riscv: rework page table bootstrap
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Date: Thu, 20 Jun 2024 19:00:21 UTC
The branch main has been updated by mhorne:
URL: https://cgit.FreeBSD.org/src/commit/?id=de09dcebd720d5776df4cc4e67ffc7da757e4305
commit de09dcebd720d5776df4cc4e67ffc7da757e4305
Author: Mitchell Horne <mhorne@FreeBSD.org>
AuthorDate: 2024-06-20 18:30:17 +0000
Commit: Mitchell Horne <mhorne@FreeBSD.org>
CommitDate: 2024-06-20 18:33:19 +0000
riscv: rework page table bootstrap
The overall goal of the change is to reduce the amount of work done in
locore assembly, and defer as much as possible until pmap_bootstrap().
Currently, half the setup is done in assembly, and then we pass the l1pt
address to pmap_bootstrap() where it is amended with other mappings.
Inspiration and understanding has been taken from amd64's
create_pagetables() routine, and I try to present the page table
construction in the same way: a linear procedure with commentary
explaining what we are doing and why. Thus the core of the new
implementation is contained in pmap_create_pagetables().
Once pmap_create_pagetables() has finished, we switch to the new
pagetable root and leave the bootstrap ones created by locore behind,
resulting in a minimal 8kB of wasted space.
Having the whole procedure in one place, in C code, allows it to be more
easily understood, while also making it more amenable to future changes
which depend on CPU feature/errata detection.
Note that with this change the size of the early devmap is bumped up
from one to four L2 pages (8MB).
Reviewed by: markj
MFC after: 1 month
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D45327
---
sys/riscv/include/pte.h | 2 -
sys/riscv/include/vmparam.h | 7 +-
sys/riscv/riscv/genassym.c | 2 +
sys/riscv/riscv/locore.S | 87 +++++------
sys/riscv/riscv/pmap.c | 355 ++++++++++++++++++++++++++++----------------
5 files changed, 272 insertions(+), 181 deletions(-)
diff --git a/sys/riscv/include/pte.h b/sys/riscv/include/pte.h
index da7bd051e122..031cae667f0c 100644
--- a/sys/riscv/include/pte.h
+++ b/sys/riscv/include/pte.h
@@ -93,5 +93,3 @@ typedef uint64_t pn_t; /* page number */
#define PTE_SIZE 8
#endif /* !_MACHINE_PTE_H_ */
-
-/* End of pte.h */
diff --git a/sys/riscv/include/vmparam.h b/sys/riscv/include/vmparam.h
index 7bfa587ce37c..c750791bb280 100644
--- a/sys/riscv/include/vmparam.h
+++ b/sys/riscv/include/vmparam.h
@@ -238,13 +238,16 @@
extern vm_paddr_t dmap_phys_base;
extern vm_paddr_t dmap_phys_max;
extern vm_offset_t dmap_max_addr;
-extern vm_offset_t init_pt_va;
#endif
#define ZERO_REGION_SIZE (64 * 1024) /* 64KB */
+/*
+ * The top of KVA is reserved for early device mappings.
+ */
#define DEVMAP_MAX_VADDR VM_MAX_KERNEL_ADDRESS
-#define PMAP_MAPDEV_EARLY_SIZE L2_SIZE
+#define DEVMAP_MIN_VADDR (DEVMAP_MAX_VADDR - PMAP_MAPDEV_EARLY_SIZE)
+#define PMAP_MAPDEV_EARLY_SIZE (4 * L2_SIZE)
/*
* No non-transparent large page support in the pmap.
diff --git a/sys/riscv/riscv/genassym.c b/sys/riscv/riscv/genassym.c
index b1e1034fd479..105e17e679b7 100644
--- a/sys/riscv/riscv/genassym.c
+++ b/sys/riscv/riscv/genassym.c
@@ -60,6 +60,8 @@ ASSYM(VM_MAXUSER_ADDRESS, VM_MAXUSER_ADDRESS);
ASSYM(VM_MAX_KERNEL_ADDRESS, VM_MAX_KERNEL_ADDRESS);
ASSYM(PMAP_MAPDEV_EARLY_SIZE, PMAP_MAPDEV_EARLY_SIZE);
+ASSYM(PM_SATP, offsetof(struct pmap, pm_satp));
+
ASSYM(PCB_ONFAULT, offsetof(struct pcb, pcb_onfault));
ASSYM(PCB_SIZE, sizeof(struct pcb));
ASSYM(PCB_RA, offsetof(struct pcb, pcb_ra));
diff --git a/sys/riscv/riscv/locore.S b/sys/riscv/riscv/locore.S
index 17fdcc8ef55c..f7363fd025a7 100644
--- a/sys/riscv/riscv/locore.S
+++ b/sys/riscv/riscv/locore.S
@@ -1,6 +1,10 @@
/*-
+ * SPDX-License-Identifier: BSD-2-Clause
+ *
* Copyright (c) 2015-2018 Ruslan Bukin <br@bsdpad.com>
* All rights reserved.
+ * Copyright (c) 2019-2021 Mitchell Horne <mhorne@FreeBSD.org>
+ * Copyright (c) 2022-2024 The FreeBSD Foundation
*
* Portions of this software were developed by SRI International and the
* University of Cambridge Computer Laboratory under DARPA/AFRL contract
@@ -10,6 +14,9 @@
* Computer Laboratory as part of the CTSRD Project, with support from the
* UK Higher Education Innovation Fund (HEIF).
*
+ * Portions of this software were developed by Mitchell Horne
+ * <mhorne@FreeBSD.org> under sponsorship from the FreeBSD Foundation.
+ *
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
@@ -36,7 +43,6 @@
#include <machine/asm.h>
#include <machine/param.h>
-#include <machine/trap.h>
#include <machine/riscvreg.h>
#include <machine/pte.h>
@@ -104,16 +110,24 @@ _start:
mv a1, zero
/*
- * Set up page tables: map a 1GB region starting at KERNBASE using 2MB
- * superpages, starting from the first 2MB physical page into which the
- * kernel was loaded. Also reserve an L2 page for the early device map
- * and map the DTB, if any, using the second-last entry of that L2
- * page. This is hopefully enough to get us to pmap_bootstrap().
+ * Set up page tables: Our goal is to enable virtual memory, doing the
+ * minimum amount of work in assembly; just what is required to
+ * bootstrap. We will construct the real page tables in C code, in
+ * pmap_bootstrap().
+ *
+ * Here we map a 1GB region starting at KERNBASE using 2MB superpages,
+ * starting from the first 2MB physical page into which the kernel was
+ * loaded.
*
- * Implementations are required to provide SV39 mode, so we use that
- * initially and will optionally enable SV48 mode during kernel pmap
- * initialization.
+ * We also use an L1 entry to create a 1GB identity map (1:1 PA->VA).
+ * This is useful for two reasons:
+ * - handling the DTB pointer passed from SBI firmware (physical addr)
+ * - simpler construction of pagetables in pmap_bootstrap()
*
+ * Implementations are required to provide Sv39 mode, so we use that
+ * here and will conditionally enable Sv48 (or higher) later.
+ *
+ * We arrive here with:
* a0 - modulep or zero
* a1 - zero or dtbp
*/
@@ -122,7 +136,7 @@ pagetables:
jal get_physmem
/* Construct 1GB Identity Map (1:1 PA->VA) */
- lla s1, pagetable_l1
+ lla s1, bootstrap_pt_l1
srli s2, s9, L1_SHIFT /* kernstart >> L1_SHIFT */
andi a5, s2, Ln_ADDR_MASK /* & Ln_ADDR_MASK */
@@ -136,11 +150,11 @@ pagetables:
add t0, s1, a5
sd t6, (t0) /* Store new PTE */
- /* Construct the virtual address space */
+ /* Construct the virtual address space at KERNBASE */
/* Add L1 entry for kernel */
- lla s1, pagetable_l1
- lla s2, pagetable_l2 /* Link to next level PN */
+ lla s1, bootstrap_pt_l1
+ lla s2, bootstrap_pt_l2 /* Link to next level PN */
srli s2, s2, PAGE_SHIFT
li a5, KERNBASE
@@ -157,9 +171,9 @@ pagetables:
sd t6, (t0)
/* Level 2 superpages (512 x 2MiB) */
- lla s1, pagetable_l2
+ lla s1, bootstrap_pt_l2
srli t4, s9, L2_SHIFT /* Div physmem base by 2 MiB */
- li t2, 512 /* Build 512 entries */
+ li t2, Ln_ENTRIES /* Build 512 entries */
add t3, t4, t2
li t0, (PTE_KERN | PTE_X)
1:
@@ -171,24 +185,6 @@ pagetables:
addi t4, t4, 1
bltu t4, t3, 1b
- /* Create an L1 table entry for early devmap */
- lla s1, pagetable_l1
- lla s2, pagetable_l2_devmap /* Link to next level PN */
- srli s2, s2, PAGE_SHIFT
-
- li a5, (VM_MAX_KERNEL_ADDRESS - PMAP_MAPDEV_EARLY_SIZE)
- srli a5, a5, L1_SHIFT /* >> L1_SHIFT */
- andi a5, a5, Ln_ADDR_MASK /* & Ln_ADDR_MASK */
- li t4, PTE_V
- slli t5, s2, PTE_PPN0_S /* (s2 << PTE_PPN0_S) */
- or t6, t4, t5
-
- /* Store the L1 table entry */
- li a6, PTE_SIZE
- mulw a5, a5, a6
- add t0, s1, a5
- sd t6, (t0)
-
/* Page tables END */
/*
@@ -203,7 +199,7 @@ pagetables:
csrw stvec, t0
/* Set page tables base register */
- lla s2, pagetable_l1
+ lla s2, bootstrap_pt_l1
srli s2, s2, PAGE_SHIFT
li t0, SATP_MODE_SV39
or s2, s2, t0
@@ -244,8 +240,6 @@ va:
bltu t0, t1, 1b
/* Fill riscv_bootparams */
- la t0, pagetable_l1
- sd t0, RISCV_BOOTPARAMS_KERN_L1PT(sp)
sd s9, RISCV_BOOTPARAMS_KERN_PHYS(sp)
la t0, initstack
@@ -278,12 +272,13 @@ initstack:
.space (PAGE_SIZE * KSTACK_PAGES)
initstack_end:
- .align 12
-pagetable_l1:
- .space PAGE_SIZE
-pagetable_l2:
+/*
+ * Static space for the bootstrap page tables. Unused after pmap_bootstrap().
+ */
+ .balign PAGE_SIZE
+bootstrap_pt_l1:
.space PAGE_SIZE
-pagetable_l2_devmap:
+bootstrap_pt_l2:
.space PAGE_SIZE
.align 3
@@ -292,10 +287,6 @@ virt_map:
hart_lottery:
.space 4
- .globl init_pt_va
-init_pt_va:
- .quad pagetable_l2 /* XXX: Keep page tables VA */
-
#ifndef SMP
ENTRY(mpentry)
1:
@@ -343,10 +334,8 @@ ENTRY(mpentry)
csrw stvec, t0
/* Set page tables base register */
- lla s2, pagetable_l1
- srli s2, s2, PAGE_SHIFT
- li t0, SATP_MODE_SV39
- or s2, s2, t0
+ lla t2, kernel_pmap_store
+ ld s2, PM_SATP(t2)
sfence.vma
csrw satp, s2
diff --git a/sys/riscv/riscv/pmap.c b/sys/riscv/riscv/pmap.c
index ca051a9e4416..937bb22371e2 100644
--- a/sys/riscv/riscv/pmap.c
+++ b/sys/riscv/riscv/pmap.c
@@ -243,8 +243,7 @@ CTASSERT((DMAP_MIN_ADDRESS & ~L1_OFFSET) == DMAP_MIN_ADDRESS);
CTASSERT((DMAP_MAX_ADDRESS & ~L1_OFFSET) == DMAP_MAX_ADDRESS);
/*
- * This code assumes that the early DEVMAP is L2_SIZE aligned and is fully
- * contained within a single L2 entry.
+ * This code assumes that the early DEVMAP is L2_SIZE aligned.
*/
CTASSERT((PMAP_MAPDEV_EARLY_SIZE & L2_OFFSET) == 0);
@@ -324,6 +323,8 @@ static int pmap_unuse_pt(pmap_t, vm_offset_t, pd_entry_t, struct spglist *);
static int pmap_change_attr_locked(vm_offset_t va, vm_size_t size, int mode);
+static uint64_t pmap_satp_mode(void);
+
#define pmap_clear(pte) pmap_store(pte, 0)
#define pmap_clear_bits(pte, bits) atomic_clear_64(pte, bits)
#define pmap_load_store(pte, entry) atomic_swap_64(pte, entry)
@@ -361,6 +362,28 @@ pagezero(void *p)
((((l2) & ~PTE_HI_MASK) >> PTE_PPN1_S) << L2_SHIFT)
#define PTE_TO_VM_PAGE(pte) PHYS_TO_VM_PAGE(PTE_TO_PHYS(pte))
+/*
+ * Construct a page table entry of the specified level pointing to physical
+ * address pa, with PTE bits 'bits'.
+ *
+ * A leaf PTE of any level must point to an address matching its alignment,
+ * e.g. L2 pages must be 2MB aligned in memory.
+ */
+#define L1_PTE(pa, bits) ((((pa) >> L1_SHIFT) << PTE_PPN2_S) | (bits))
+#define L2_PTE(pa, bits) ((((pa) >> L2_SHIFT) << PTE_PPN1_S) | (bits))
+#define L3_PTE(pa, bits) ((((pa) >> L3_SHIFT) << PTE_PPN0_S) | (bits))
+
+/*
+ * Construct a page directory entry (PDE), pointing to next level entry at pa,
+ * with PTE bits 'bits'.
+ *
+ * Unlike PTEs, page directory entries can point to any 4K-aligned physical
+ * address.
+ */
+#define L0_PDE(pa, bits) L3_PTE(pa, bits)
+#define L1_PDE(pa, bits) L3_PTE(pa, bits)
+#define L2_PDE(pa, bits) L3_PTE(pa, bits)
+
static __inline pd_entry_t *
pmap_l0(pmap_t pmap, vm_offset_t va)
{
@@ -501,45 +524,20 @@ pmap_distribute_l1(struct pmap *pmap, vm_pindex_t l1index,
mtx_unlock(&allpmaps_lock);
}
+/*
+ * This should only be used during pmap bootstrap e.g. by
+ * pmap_create_pagetables().
+ */
static pt_entry_t *
-pmap_early_page_idx(vm_offset_t l1pt, vm_offset_t va, u_int *l1_slot,
- u_int *l2_slot)
+pmap_early_alloc_tables(vm_paddr_t *freemempos, int npages)
{
- pt_entry_t *l2;
- pd_entry_t *l1 __diagused;
-
- l1 = (pd_entry_t *)l1pt;
- *l1_slot = (va >> L1_SHIFT) & Ln_ADDR_MASK;
+ pt_entry_t *pt;
- /* Check locore has used a table L1 map */
- KASSERT((l1[*l1_slot] & PTE_RX) == 0,
- ("Invalid bootstrap L1 table"));
+ pt = (pt_entry_t *)*freemempos;
+ *freemempos += npages * PAGE_SIZE;
+ bzero(pt, npages * PAGE_SIZE);
- /* Find the address of the L2 table */
- l2 = (pt_entry_t *)init_pt_va;
- *l2_slot = pmap_l2_index(va);
-
- return (l2);
-}
-
-static vm_paddr_t
-pmap_early_vtophys(vm_offset_t l1pt, vm_offset_t va)
-{
- u_int l1_slot, l2_slot;
- pt_entry_t *l2;
- vm_paddr_t ret;
-
- l2 = pmap_early_page_idx(l1pt, va, &l1_slot, &l2_slot);
-
- /* Check locore has used L2 superpages */
- KASSERT((l2[l2_slot] & PTE_RX) != 0,
- ("Invalid bootstrap L2 table"));
-
- /* L2 is superpages */
- ret = L2PTE_TO_PHYS(l2[l2_slot]);
- ret += (va & L2_OFFSET);
-
- return (ret);
+ return (pt);
}
static void
@@ -575,38 +573,152 @@ pmap_bootstrap_dmap(vm_offset_t kern_l1, vm_paddr_t min_pa, vm_paddr_t max_pa)
sfence_vma();
}
-static vm_offset_t
-pmap_bootstrap_l3(vm_offset_t l1pt, vm_offset_t va, vm_offset_t l3_start)
+/*
+ * Create a new set of pagetables to run the kernel with.
+ *
+ * An initial, temporary setup was created in locore.S, which serves well
+ * enough to get us this far. It mapped kernstart -> KERNBASE, using 2MB
+ * superpages, and created a 1GB identity map, which allows this function
+ * to dereference physical addresses.
+ *
+ * The memory backing these page tables is allocated in the space
+ * immediately following the kernel's preload area. Depending on the size
+ * of this area, some, all, or none of these pages can be implicitly
+ * mapped by the kernel's 2MB mappings. This memory will only ever be
+ * accessed through the direct map, however.
+ */
+static vm_paddr_t
+pmap_create_pagetables(vm_paddr_t kernstart, vm_size_t kernlen,
+ vm_paddr_t min_pa, vm_paddr_t max_pa, vm_paddr_t *root_pt_phys)
{
- vm_offset_t l3pt;
- pt_entry_t entry;
- pd_entry_t *l2;
- vm_paddr_t pa;
- u_int l2_slot;
- pn_t pn;
+ pt_entry_t *l0, *l1, *kern_l2, *kern_l3, *devmap_l3;
+ pd_entry_t *devmap_l2;
+ vm_paddr_t kernend, freemempos, pa;
+ int nkernl2, nkernl3, ndevmapl3;
+ int i, slot;
+ int mode;
- KASSERT((va & L2_OFFSET) == 0, ("Invalid virtual address"));
+ kernend = kernstart + kernlen;
- l2 = pmap_l2(kernel_pmap, va);
- l2 = (pd_entry_t *)((uintptr_t)l2 & ~(PAGE_SIZE - 1));
- l2_slot = pmap_l2_index(va);
- l3pt = l3_start;
+ /* Static allocations begin after the kernel staging area. */
+ freemempos = roundup2(kernend, PAGE_SIZE);
- for (; va < VM_MAX_KERNEL_ADDRESS; l2_slot++, va += L2_SIZE) {
- KASSERT(l2_slot < Ln_ENTRIES, ("Invalid L2 index"));
+ /* Detect Sv48 mode. */
+ mode = PMAP_MODE_SV39;
+ TUNABLE_INT_FETCH("vm.pmap.mode", &mode);
- pa = pmap_early_vtophys(l1pt, l3pt);
- pn = (pa / PAGE_SIZE);
- entry = (PTE_V);
- entry |= (pn << PTE_PPN0_S);
- pmap_store(&l2[l2_slot], entry);
- l3pt += PAGE_SIZE;
+ if (mode == PMAP_MODE_SV48 && (mmu_caps & MMU_SV48) != 0) {
+ /*
+ * Sv48 mode: allocate an L0 page table to be the root. The
+ * layout of KVA is otherwise identical to Sv39.
+ */
+ l0 = pmap_early_alloc_tables(&freemempos, 1);
+ *root_pt_phys = (vm_paddr_t)l0;
+ pmap_mode = PMAP_MODE_SV48;
+ } else {
+ l0 = NULL;
+ }
+
+ /*
+ * Allocate an L1 page table.
+ */
+ l1 = pmap_early_alloc_tables(&freemempos, 1);
+ if (pmap_mode == PMAP_MODE_SV39)
+ *root_pt_phys = (vm_paddr_t)l1;
+
+ /*
+ * Allocate a set of L2 page tables for KVA. Most likely, only 1 is
+ * needed.
+ */
+ nkernl2 = howmany(howmany(kernlen, L2_SIZE), Ln_ENTRIES);
+ kern_l2 = pmap_early_alloc_tables(&freemempos, nkernl2);
+
+ /*
+ * Allocate an L2 page table for the static devmap, located at the end
+ * of KVA. We can expect that the devmap will always be less than 1GB
+ * in size.
+ */
+ devmap_l2 = pmap_early_alloc_tables(&freemempos, 1);
+
+ /* Allocate L3 page tables for the devmap. */
+ ndevmapl3 = howmany(howmany(PMAP_MAPDEV_EARLY_SIZE, L3_SIZE),
+ Ln_ENTRIES);
+ devmap_l3 = pmap_early_alloc_tables(&freemempos, ndevmapl3);
+
+ /*
+ * Allocate some L3 bootstrap pages, for early KVA allocations before
+ * vm_mem_init() has run. For example, the message buffer.
+ *
+ * A somewhat arbitrary choice of 32MB. This should be more than enough
+ * for any early allocations. There is no need to worry about waste, as
+ * whatever is not used will be consumed by later calls to
+ * pmap_growkernel().
+ */
+ nkernl3 = 16;
+ kern_l3 = pmap_early_alloc_tables(&freemempos, nkernl3);
+
+ /* Allocations are done. */
+ if (freemempos < roundup2(kernend, L2_SIZE))
+ freemempos = roundup2(kernend, L2_SIZE);
+
+ /*
+ * Map the kernel (and preloaded modules or data) using L2 superpages.
+ *
+ * kernstart is 2MB-aligned. This is enforced by loader(8) and required
+ * by locore assembly.
+ *
+ * TODO: eventually, this should be done with proper permissions for
+ * each segment, rather than mapping the entire kernel and preloaded
+ * modules RWX.
+ */
+ slot = pmap_l2_index(KERNBASE);
+ for (pa = kernstart; pa < kernend; pa += L2_SIZE, slot++) {
+ pmap_store(&kern_l2[slot], L2_PTE(pa, PTE_KERN | PTE_X));
+ }
+
+ /*
+ * Connect the L3 bootstrap pages to the kernel L2 table. The L3 PTEs
+ * themselves are invalid.
+ */
+ slot = pmap_l2_index(freemempos - kernstart + KERNBASE);
+ for (i = 0; i < nkernl3; i++, slot++) {
+ pa = (vm_paddr_t)kern_l3 + ptoa(i);
+ pmap_store(&kern_l2[slot], L2_PDE(pa, PTE_V));
+ }
+
+ /* Connect the L2 tables to the L1 table. */
+ slot = pmap_l1_index(KERNBASE);
+ for (i = 0; i < nkernl2; i++, slot++) {
+ pa = (vm_paddr_t)kern_l2 + ptoa(i);
+ pmap_store(&l1[slot], L1_PDE(pa, PTE_V));
+ }
+
+ /* Connect the L1 table to L0, if in use. */
+ if (pmap_mode == PMAP_MODE_SV48) {
+ slot = pmap_l0_index(KERNBASE);
+ pmap_store(&l0[slot], L0_PDE((vm_paddr_t)l1, PTE_V));
+ }
+
+ /*
+ * Connect the devmap L3 pages to the L2 table. The devmap PTEs
+ * themselves are invalid.
+ */
+ slot = pmap_l2_index(DEVMAP_MIN_VADDR);
+ for (i = 0; i < ndevmapl3; i++, slot++) {
+ pa = (vm_paddr_t)devmap_l3 + ptoa(i);
+ pmap_store(&devmap_l2[slot], L2_PDE(pa, PTE_V));
}
- /* Clean the L2 page table */
- memset((void *)l3_start, 0, l3pt - l3_start);
+ /* Connect the devmap L2 pages to the L1 table. */
+ slot = pmap_l1_index(DEVMAP_MIN_VADDR);
+ pa = (vm_paddr_t)devmap_l2;
+ pmap_store(&l1[slot], L1_PDE(pa, PTE_V));
+
+ /* Bootstrap the direct map. */
+ pmap_bootstrap_dmap((vm_offset_t)l1, min_pa, max_pa);
- return (l3pt);
+ /* Return the next position of free memory */
+ return (freemempos);
}
/*
@@ -616,19 +728,17 @@ void
pmap_bootstrap(vm_offset_t l1pt, vm_paddr_t kernstart, vm_size_t kernlen)
{
vm_paddr_t physmap[PHYS_AVAIL_ENTRIES];
- uint64_t satp;
- vm_offset_t dpcpu, freemempos, l0pv, msgbufpv;
- vm_paddr_t l0pa, l1pa, max_pa, min_pa, pa;
- pd_entry_t *l0p;
- u_int l1_slot, l2_slot;
+ vm_paddr_t freemempos;
+ vm_paddr_t max_pa, min_pa, pa;
+ vm_paddr_t root_pt_phys;
+ vm_offset_t freeva;
+ vm_offset_t dpcpu, msgbufpv;
+ pt_entry_t *pte;
u_int physmap_idx;
- int i, mode;
+ int i;
printf("pmap_bootstrap %lx %lx %lx\n", l1pt, kernstart, kernlen);
- /* Set this early so we can use the pagetable walking functions */
- kernel_pmap_store.pm_top = (pd_entry_t *)l1pt;
- kernel_pmap_store.pm_stage = PM_STAGE1;
PMAP_LOCK_INIT(kernel_pmap);
TAILQ_INIT(&kernel_pmap->pm_pvchunk);
vm_radix_init(&kernel_pmap->pm_root);
@@ -664,74 +774,63 @@ pmap_bootstrap(vm_offset_t l1pt, vm_paddr_t kernstart, vm_size_t kernlen)
printf("min_pa %lx\n", min_pa);
printf("max_pa %lx\n", max_pa);
- /* Create a direct map region early so we can use it for pa -> va */
- pmap_bootstrap_dmap(l1pt, min_pa, max_pa);
-
- /*
- * Read the page table to find out what is already mapped.
- * This assumes we have mapped a block of memory from KERNBASE
- * using a single L1 entry.
- */
- (void)pmap_early_page_idx(l1pt, KERNBASE, &l1_slot, &l2_slot);
-
- /* Sanity check the index, KERNBASE should be the first VA */
- KASSERT(l2_slot == 0, ("The L2 index is non-zero"));
-
- freemempos = roundup2(KERNBASE + kernlen, PAGE_SIZE);
-
- /* Create the l3 tables for the early devmap */
- freemempos = pmap_bootstrap_l3(l1pt,
- VM_MAX_KERNEL_ADDRESS - PMAP_MAPDEV_EARLY_SIZE, freemempos);
+ /* Create a new set of pagetables to run the kernel in. */
+ freemempos = pmap_create_pagetables(kernstart, kernlen, min_pa, max_pa,
+ &root_pt_phys);
+ /* Switch to the newly created page tables. */
+ kernel_pmap->pm_stage = PM_STAGE1;
+ kernel_pmap->pm_top = (pd_entry_t *)PHYS_TO_DMAP(root_pt_phys);
+ kernel_pmap->pm_satp = atop(root_pt_phys) | pmap_satp_mode();
+ csr_write(satp, kernel_pmap->pm_satp);
sfence_vma();
-#define alloc_pages(var, np) \
- (var) = freemempos; \
- freemempos += (np * PAGE_SIZE); \
- memset((char *)(var), 0, ((np) * PAGE_SIZE));
-
- mode = 0;
- TUNABLE_INT_FETCH("vm.pmap.mode", &mode);
- if (mode == PMAP_MODE_SV48 && (mmu_caps & MMU_SV48) != 0) {
- /*
- * Enable SV48 mode: allocate an L0 page and set SV48 mode in
- * SATP. If the implementation does not provide SV48 mode,
- * the mode read back from the (WARL) SATP register will be
- * unchanged, and we continue in SV39 mode.
- */
- alloc_pages(l0pv, 1);
- l0p = (void *)l0pv;
- l1pa = pmap_early_vtophys(l1pt, l1pt);
- l0p[pmap_l0_index(KERNBASE)] = PTE_V |
- ((l1pa >> PAGE_SHIFT) << PTE_PPN0_S);
-
- l0pa = pmap_early_vtophys(l1pt, l0pv);
- csr_write(satp, (l0pa >> PAGE_SHIFT) | SATP_MODE_SV48);
- satp = csr_read(satp);
- if ((satp & SATP_MODE_M) == SATP_MODE_SV48) {
- pmap_mode = PMAP_MODE_SV48;
- kernel_pmap_store.pm_top = l0p;
- } else {
- /* Mode didn't change, give the page back. */
- freemempos -= PAGE_SIZE;
- }
- }
-
- /* Allocate dynamic per-cpu area. */
- alloc_pages(dpcpu, DPCPU_SIZE / PAGE_SIZE);
+ /*
+ * Now, we need to make a few more static reservations from KVA.
+ *
+ * Set freeva to freemempos virtual address, and be sure to advance
+ * them together.
+ */
+ freeva = freemempos - kernstart + KERNBASE;
+#define reserve_space(var, pa, size) \
+ do { \
+ var = freeva; \
+ pa = freemempos; \
+ freeva += size; \
+ freemempos += size; \
+ } while (0)
+
+ /* Allocate the dynamic per-cpu area. */
+ reserve_space(dpcpu, pa, DPCPU_SIZE);
+
+ /* Map it. */
+ pte = pmap_l3(kernel_pmap, dpcpu);
+ KASSERT(pte != NULL, ("Bootstrap pages missing"));
+ for (i = 0; i < howmany(DPCPU_SIZE, PAGE_SIZE); i++)
+ pmap_store(&pte[i], L3_PTE(pa + ptoa(i), PTE_KERN));
+
+ /* Now, it can be initialized. */
dpcpu_init((void *)dpcpu, 0);
/* Allocate memory for the msgbuf, e.g. for /sbin/dmesg */
- alloc_pages(msgbufpv, round_page(msgbufsize) / PAGE_SIZE);
+ reserve_space(msgbufpv, pa, round_page(msgbufsize));
msgbufp = (void *)msgbufpv;
- virtual_avail = roundup2(freemempos, L2_SIZE);
- virtual_end = VM_MAX_KERNEL_ADDRESS - PMAP_MAPDEV_EARLY_SIZE;
- kernel_vm_end = virtual_avail;
+ /* Map it. */
+ pte = pmap_l3(kernel_pmap, msgbufpv);
+ KASSERT(pte != NULL, ("Bootstrap pages missing"));
+ for (i = 0; i < howmany(msgbufsize, PAGE_SIZE); i++)
+ pmap_store(&pte[i], L3_PTE(pa + ptoa(i), PTE_KERN));
+
+#undef reserve_space
- pa = pmap_early_vtophys(l1pt, freemempos);
+ /* Mark the bounds of our available virtual address space */
+ virtual_avail = kernel_vm_end = freeva;
+ virtual_end = DEVMAP_MIN_VADDR;
- physmem_exclude_region(kernstart, pa - kernstart, EXFLAG_NOALLOC);
+ /* Exclude the reserved physical memory from allocations. */
+ physmem_exclude_region(kernstart, freemempos - kernstart,
+ EXFLAG_NOALLOC);
}
/*