// 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 #include #include #include #include #include #include /* 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 __init setup_kuep(bool disabled) { 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