| // SPDX-License-Identifier: GPL-2.0-or-later |
| /* |
| * Modifications by Matt Porter (mporter@mvista.com) to support |
| * PPC44x Book E processors. |
| * |
| * This file contains the routines for initializing the MMU |
| * on the 4xx series of chips. |
| * -- paulus |
| * |
| * Derived from arch/ppc/mm/init.c: |
| * Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org) |
| * |
| * Modifications by Paul Mackerras (PowerMac) (paulus@cs.anu.edu.au) |
| * and Cort Dougan (PReP) (cort@cs.nmt.edu) |
| * Copyright (C) 1996 Paul Mackerras |
| * |
| * Derived from "arch/i386/mm/init.c" |
| * Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds |
| */ |
| |
| #include <linux/init.h> |
| #include <linux/memblock.h> |
| |
| #include <asm/mmu.h> |
| #include <asm/page.h> |
| #include <asm/cacheflush.h> |
| #include <asm/code-patching.h> |
| #include <asm/smp.h> |
| |
| #include <mm/mmu_decl.h> |
| |
| /* Used by the 44x TLB replacement exception handler. |
| * Just needed it declared someplace. |
| */ |
| unsigned int tlb_44x_index; /* = 0 */ |
| unsigned int tlb_44x_hwater = PPC44x_TLB_SIZE - 1 - PPC44x_EARLY_TLBS; |
| int icache_44x_need_flush; |
| |
| unsigned long tlb_47x_boltmap[1024/8]; |
| |
| static void ppc44x_update_tlb_hwater(void) |
| { |
| /* The TLB miss handlers hard codes the watermark in a cmpli |
| * instruction to improve performances rather than loading it |
| * from the global variable. Thus, we patch the instructions |
| * in the 2 TLB miss handlers when updating the value |
| */ |
| modify_instruction_site(&patch__tlb_44x_hwater_D, 0xffff, tlb_44x_hwater); |
| modify_instruction_site(&patch__tlb_44x_hwater_I, 0xffff, tlb_44x_hwater); |
| } |
| |
| /* |
| * "Pins" a 256MB TLB entry in AS0 for kernel lowmem for 44x type MMU |
| */ |
| static void __init ppc44x_pin_tlb(unsigned int virt, unsigned int phys) |
| { |
| unsigned int entry = tlb_44x_hwater--; |
| |
| ppc44x_update_tlb_hwater(); |
| |
| mtspr(SPRN_MMUCR, 0); |
| |
| __asm__ __volatile__( |
| "tlbwe %2,%3,%4\n" |
| "tlbwe %1,%3,%5\n" |
| "tlbwe %0,%3,%6\n" |
| : |
| : "r" (PPC44x_TLB_SW | PPC44x_TLB_SR | PPC44x_TLB_SX | PPC44x_TLB_G), |
| "r" (phys), |
| "r" (virt | PPC44x_TLB_VALID | PPC44x_TLB_256M), |
| "r" (entry), |
| "i" (PPC44x_TLB_PAGEID), |
| "i" (PPC44x_TLB_XLAT), |
| "i" (PPC44x_TLB_ATTRIB)); |
| } |
| |
| static int __init ppc47x_find_free_bolted(void) |
| { |
| unsigned int mmube0 = mfspr(SPRN_MMUBE0); |
| unsigned int mmube1 = mfspr(SPRN_MMUBE1); |
| |
| if (!(mmube0 & MMUBE0_VBE0)) |
| return 0; |
| if (!(mmube0 & MMUBE0_VBE1)) |
| return 1; |
| if (!(mmube0 & MMUBE0_VBE2)) |
| return 2; |
| if (!(mmube1 & MMUBE1_VBE3)) |
| return 3; |
| if (!(mmube1 & MMUBE1_VBE4)) |
| return 4; |
| if (!(mmube1 & MMUBE1_VBE5)) |
| return 5; |
| return -1; |
| } |
| |
| static void __init ppc47x_update_boltmap(void) |
| { |
| unsigned int mmube0 = mfspr(SPRN_MMUBE0); |
| unsigned int mmube1 = mfspr(SPRN_MMUBE1); |
| |
| if (mmube0 & MMUBE0_VBE0) |
| __set_bit((mmube0 >> MMUBE0_IBE0_SHIFT) & 0xff, |
| tlb_47x_boltmap); |
| if (mmube0 & MMUBE0_VBE1) |
| __set_bit((mmube0 >> MMUBE0_IBE1_SHIFT) & 0xff, |
| tlb_47x_boltmap); |
| if (mmube0 & MMUBE0_VBE2) |
| __set_bit((mmube0 >> MMUBE0_IBE2_SHIFT) & 0xff, |
| tlb_47x_boltmap); |
| if (mmube1 & MMUBE1_VBE3) |
| __set_bit((mmube1 >> MMUBE1_IBE3_SHIFT) & 0xff, |
| tlb_47x_boltmap); |
| if (mmube1 & MMUBE1_VBE4) |
| __set_bit((mmube1 >> MMUBE1_IBE4_SHIFT) & 0xff, |
| tlb_47x_boltmap); |
| if (mmube1 & MMUBE1_VBE5) |
| __set_bit((mmube1 >> MMUBE1_IBE5_SHIFT) & 0xff, |
| tlb_47x_boltmap); |
| } |
| |
| /* |
| * "Pins" a 256MB TLB entry in AS0 for kernel lowmem for 47x type MMU |
| */ |
| static void ppc47x_pin_tlb(unsigned int virt, unsigned int phys) |
| { |
| unsigned int rA; |
| int bolted; |
| |
| /* Base rA is HW way select, way 0, bolted bit set */ |
| rA = 0x88000000; |
| |
| /* Look for a bolted entry slot */ |
| bolted = ppc47x_find_free_bolted(); |
| BUG_ON(bolted < 0); |
| |
| /* Insert bolted slot number */ |
| rA |= bolted << 24; |
| |
| pr_debug("256M TLB entry for 0x%08x->0x%08x in bolt slot %d\n", |
| virt, phys, bolted); |
| |
| mtspr(SPRN_MMUCR, 0); |
| |
| __asm__ __volatile__( |
| "tlbwe %2,%3,0\n" |
| "tlbwe %1,%3,1\n" |
| "tlbwe %0,%3,2\n" |
| : |
| : "r" (PPC47x_TLB2_SW | PPC47x_TLB2_SR | |
| PPC47x_TLB2_SX |
| #ifdef CONFIG_SMP |
| | PPC47x_TLB2_M |
| #endif |
| ), |
| "r" (phys), |
| "r" (virt | PPC47x_TLB0_VALID | PPC47x_TLB0_256M), |
| "r" (rA)); |
| } |
| |
| void __init MMU_init_hw(void) |
| { |
| /* This is not useful on 47x but won't hurt either */ |
| ppc44x_update_tlb_hwater(); |
| |
| flush_instruction_cache(); |
| } |
| |
| unsigned long __init mmu_mapin_ram(unsigned long base, unsigned long top) |
| { |
| unsigned long addr; |
| unsigned long memstart = memstart_addr & ~(PPC_PIN_SIZE - 1); |
| |
| /* Pin in enough TLBs to cover any lowmem not covered by the |
| * initial 256M mapping established in head_44x.S */ |
| for (addr = memstart + PPC_PIN_SIZE; addr < lowmem_end_addr; |
| addr += PPC_PIN_SIZE) { |
| if (mmu_has_feature(MMU_FTR_TYPE_47x)) |
| ppc47x_pin_tlb(addr + PAGE_OFFSET, addr); |
| else |
| ppc44x_pin_tlb(addr + PAGE_OFFSET, addr); |
| } |
| if (mmu_has_feature(MMU_FTR_TYPE_47x)) { |
| ppc47x_update_boltmap(); |
| |
| #ifdef DEBUG |
| { |
| int i; |
| |
| printk(KERN_DEBUG "bolted entries: "); |
| for (i = 0; i < 255; i++) { |
| if (test_bit(i, tlb_47x_boltmap)) |
| printk("%d ", i); |
| } |
| printk("\n"); |
| } |
| #endif /* DEBUG */ |
| } |
| return total_lowmem; |
| } |
| |
| void setup_initial_memory_limit(phys_addr_t first_memblock_base, |
| phys_addr_t first_memblock_size) |
| { |
| u64 size; |
| |
| #ifndef CONFIG_NONSTATIC_KERNEL |
| /* We don't currently support the first MEMBLOCK not mapping 0 |
| * physical on those processors |
| */ |
| BUG_ON(first_memblock_base != 0); |
| #endif |
| |
| /* 44x has a 256M TLB entry pinned at boot */ |
| size = (min_t(u64, first_memblock_size, PPC_PIN_SIZE)); |
| memblock_set_current_limit(first_memblock_base + size); |
| } |
| |
| #ifdef CONFIG_SMP |
| void __init mmu_init_secondary(int cpu) |
| { |
| unsigned long addr; |
| unsigned long memstart = memstart_addr & ~(PPC_PIN_SIZE - 1); |
| |
| /* Pin in enough TLBs to cover any lowmem not covered by the |
| * initial 256M mapping established in head_44x.S |
| * |
| * WARNING: This is called with only the first 256M of the |
| * linear mapping in the TLB and we can't take faults yet |
| * so beware of what this code uses. It runs off a temporary |
| * stack. current (r2) isn't initialized, smp_processor_id() |
| * will not work, current thread info isn't accessible, ... |
| */ |
| for (addr = memstart + PPC_PIN_SIZE; addr < lowmem_end_addr; |
| addr += PPC_PIN_SIZE) { |
| if (mmu_has_feature(MMU_FTR_TYPE_47x)) |
| ppc47x_pin_tlb(addr + PAGE_OFFSET, addr); |
| else |
| ppc44x_pin_tlb(addr + PAGE_OFFSET, addr); |
| } |
| } |
| #endif /* CONFIG_SMP */ |
| |
| #ifdef CONFIG_PPC_KUEP |
| void setup_kuep(bool disabled) |
| { |
| if (smp_processor_id() != boot_cpuid) |
| return; |
| |
| if (disabled) |
| patch_instruction_site(&patch__tlb_44x_kuep, ppc_inst(PPC_RAW_NOP())); |
| else |
| pr_info("Activating Kernel Userspace Execution Prevention\n"); |
| |
| if (IS_ENABLED(CONFIG_PPC_47x) && disabled) |
| patch_instruction_site(&patch__tlb_47x_kuep, ppc_inst(PPC_RAW_NOP())); |
| } |
| #endif |
