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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 <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;
}
/*
* 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)
{
unsigned long p = PHYS_IMMR_BASE;
unsigned long v = VIRT_IMMR_BASE;
int offset;
if (immr_is_mapped)
return;
immr_is_mapped = true;
for (offset = 0; offset < IMMR_SIZE; offset += PAGE_SIZE)
map_kernel_page(v + offset, p + offset, PAGE_KERNEL_NCG);
}
unsigned long __init mmu_mapin_ram(unsigned long base, unsigned long top)
{
mmu_mapin_immr();
return 0;
}
void mmu_mark_initmem_nx(void)
{
}
#ifdef CONFIG_STRICT_KERNEL_RWX
void mmu_mark_rodata_ro(void)
{
}
#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();
}
void flush_instruction_cache(void)
{
isync();
mtspr(SPRN_IC_CST, IDC_INVALL);
isync();
}
#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
void __init setup_kuap(bool disabled)
{
pr_info("Activating Kernel Userspace Access Protection\n");
if (disabled)
pr_warn("KUAP cannot be disabled yet on 8xx when compiled in\n");
mtspr(SPRN_MD_AP, MD_APG_KUAP);
}
#endif
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