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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* This file contains the routines for initializing the MMU
* on the 8xx series of chips.
* -- christophe
*
* Derived from arch/powerpc/mm/40x_mmu.c:
*/
#include <linux/memblock.h>
#include <linux/mmu_context.h>
#include <linux/hugetlb.h>
#include <asm/fixmap.h>
#include <asm/code-patching.h>
#include <asm/inst.h>
#include <mm/mmu_decl.h>
#define IMMR_SIZE (FIX_IMMR_SIZE << PAGE_SHIFT)
extern int __map_without_ltlbs;
static unsigned long block_mapped_ram;
/*
* Return PA for this VA if it is in an area mapped with LTLBs or fixmap.
* Otherwise, returns 0
*/
phys_addr_t v_block_mapped(unsigned long va)
{
unsigned long p = PHYS_IMMR_BASE;
if (va >= VIRT_IMMR_BASE && va < VIRT_IMMR_BASE + IMMR_SIZE)
return p + va - VIRT_IMMR_BASE;
if (__map_without_ltlbs)
return 0;
if (va >= PAGE_OFFSET && va < PAGE_OFFSET + block_mapped_ram)
return __pa(va);
return 0;
}
/*
* Return VA for a given PA mapped with LTLBs or fixmap
* Return 0 if not mapped
*/
unsigned long p_block_mapped(phys_addr_t pa)
{
unsigned long p = PHYS_IMMR_BASE;
if (pa >= p && pa < p + IMMR_SIZE)
return VIRT_IMMR_BASE + pa - p;
if (__map_without_ltlbs)
return 0;
if (pa < block_mapped_ram)
return (unsigned long)__va(pa);
return 0;
}
static pte_t __init *early_hugepd_alloc_kernel(hugepd_t *pmdp, unsigned long va)
{
if (hpd_val(*pmdp) == 0) {
pte_t *ptep = memblock_alloc(sizeof(pte_basic_t), SZ_4K);
if (!ptep)
return NULL;
hugepd_populate_kernel((hugepd_t *)pmdp, ptep, PAGE_SHIFT_8M);
hugepd_populate_kernel((hugepd_t *)pmdp + 1, ptep, PAGE_SHIFT_8M);
}
return hugepte_offset(*(hugepd_t *)pmdp, va, PGDIR_SHIFT);
}
static int __ref __early_map_kernel_hugepage(unsigned long va, phys_addr_t pa,
pgprot_t prot, int psize, bool new)
{
pmd_t *pmdp = pmd_off_k(va);
pte_t *ptep;
if (WARN_ON(psize != MMU_PAGE_512K && psize != MMU_PAGE_8M))
return -EINVAL;
if (new) {
if (WARN_ON(slab_is_available()))
return -EINVAL;
if (psize == MMU_PAGE_512K)
ptep = early_pte_alloc_kernel(pmdp, va);
else
ptep = early_hugepd_alloc_kernel((hugepd_t *)pmdp, va);
} else {
if (psize == MMU_PAGE_512K)
ptep = pte_offset_kernel(pmdp, va);
else
ptep = hugepte_offset(*(hugepd_t *)pmdp, va, PGDIR_SHIFT);
}
if (WARN_ON(!ptep))
return -ENOMEM;
/* The PTE should never be already present */
if (new && WARN_ON(pte_present(*ptep) && pgprot_val(prot)))
return -EINVAL;
set_huge_pte_at(&init_mm, va, ptep, pte_mkhuge(pfn_pte(pa >> PAGE_SHIFT, prot)));
return 0;
}
/*
* MMU_init_hw does the chip-specific initialization of the MMU hardware.
*/
void __init MMU_init_hw(void)
{
}
static bool immr_is_mapped __initdata;
void __init mmu_mapin_immr(void)
{
if (immr_is_mapped)
return;
immr_is_mapped = true;
__early_map_kernel_hugepage(VIRT_IMMR_BASE, PHYS_IMMR_BASE,
PAGE_KERNEL_NCG, MMU_PAGE_512K, true);
}
static void mmu_mapin_ram_chunk(unsigned long offset, unsigned long top,
pgprot_t prot, bool new)
{
unsigned long v = PAGE_OFFSET + offset;
unsigned long p = offset;
WARN_ON(!IS_ALIGNED(offset, SZ_512K) || !IS_ALIGNED(top, SZ_512K));
for (; p < ALIGN(p, SZ_8M) && p < top; p += SZ_512K, v += SZ_512K)
__early_map_kernel_hugepage(v, p, prot, MMU_PAGE_512K, new);
for (; p < ALIGN_DOWN(top, SZ_8M) && p < top; p += SZ_8M, v += SZ_8M)
__early_map_kernel_hugepage(v, p, prot, MMU_PAGE_8M, new);
for (; p < ALIGN_DOWN(top, SZ_512K) && p < top; p += SZ_512K, v += SZ_512K)
__early_map_kernel_hugepage(v, p, prot, MMU_PAGE_512K, new);
if (!new)
flush_tlb_kernel_range(PAGE_OFFSET + v, PAGE_OFFSET + top);
}
unsigned long __init mmu_mapin_ram(unsigned long base, unsigned long top)
{
unsigned long etext8 = ALIGN(__pa(_etext), SZ_8M);
unsigned long sinittext = __pa(_sinittext);
bool strict_boundary = strict_kernel_rwx_enabled() || debug_pagealloc_enabled_or_kfence();
unsigned long boundary = strict_boundary ? sinittext : etext8;
unsigned long einittext8 = ALIGN(__pa(_einittext), SZ_8M);
WARN_ON(top < einittext8);
mmu_mapin_immr();
if (__map_without_ltlbs)
return 0;
mmu_mapin_ram_chunk(0, boundary, PAGE_KERNEL_TEXT, true);
if (debug_pagealloc_enabled_or_kfence()) {
top = boundary;
} else {
mmu_mapin_ram_chunk(boundary, einittext8, PAGE_KERNEL_TEXT, true);
mmu_mapin_ram_chunk(einittext8, top, PAGE_KERNEL, true);
}
if (top > SZ_32M)
memblock_set_current_limit(top);
block_mapped_ram = top;
return top;
}
void mmu_mark_initmem_nx(void)
{
unsigned long etext8 = ALIGN(__pa(_etext), SZ_8M);
unsigned long sinittext = __pa(_sinittext);
unsigned long boundary = strict_kernel_rwx_enabled() ? sinittext : etext8;
unsigned long einittext8 = ALIGN(__pa(_einittext), SZ_8M);
mmu_mapin_ram_chunk(0, boundary, PAGE_KERNEL_TEXT, false);
mmu_mapin_ram_chunk(boundary, einittext8, PAGE_KERNEL, false);
mmu_pin_tlb(block_mapped_ram, false);
}
#ifdef CONFIG_STRICT_KERNEL_RWX
void mmu_mark_rodata_ro(void)
{
unsigned long sinittext = __pa(_sinittext);
mmu_mapin_ram_chunk(0, sinittext, PAGE_KERNEL_ROX, false);
if (IS_ENABLED(CONFIG_PIN_TLB_DATA))
mmu_pin_tlb(block_mapped_ram, true);
}
#endif
void __init setup_initial_memory_limit(phys_addr_t first_memblock_base,
phys_addr_t first_memblock_size)
{
/* We don't currently support the first MEMBLOCK not mapping 0
* physical on those processors
*/
BUG_ON(first_memblock_base != 0);
/* 8xx can only access 32MB at the moment */
memblock_set_current_limit(min_t(u64, first_memblock_size, SZ_32M));
}
/*
* Set up to use a given MMU context.
* id is context number, pgd is PGD pointer.
*
* We place the physical address of the new task page directory loaded
* into the MMU base register, and set the ASID compare register with
* the new "context."
*/
void set_context(unsigned long id, pgd_t *pgd)
{
s16 offset = (s16)(__pa(swapper_pg_dir));
/* Context switch the PTE pointer for the Abatron BDI2000.
* The PGDIR is passed as second argument.
*/
if (IS_ENABLED(CONFIG_BDI_SWITCH))
abatron_pteptrs[1] = pgd;
/* Register M_TWB will contain base address of level 1 table minus the
* lower part of the kernel PGDIR base address, so that all accesses to
* level 1 table are done relative to lower part of kernel PGDIR base
* address.
*/
mtspr(SPRN_M_TWB, __pa(pgd) - offset);
/* Update context */
mtspr(SPRN_M_CASID, id - 1);
/* sync */
mb();
}
#ifdef CONFIG_PPC_KUEP
void __init setup_kuep(bool disabled)
{
if (disabled)
return;
pr_info("Activating Kernel Userspace Execution Prevention\n");
mtspr(SPRN_MI_AP, MI_APG_KUEP);
}
#endif
#ifdef CONFIG_PPC_KUAP
struct static_key_false disable_kuap_key;
EXPORT_SYMBOL(disable_kuap_key);
void __init setup_kuap(bool disabled)
{
if (disabled) {
static_branch_enable(&disable_kuap_key);
return;
}
pr_info("Activating Kernel Userspace Access Protection\n");
mtspr(SPRN_MD_AP, MD_APG_KUAP);
}
#endif
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