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Diffstat (limited to 'arch/powerpc/mm/slb_low.S')
| -rw-r--r-- | arch/powerpc/mm/slb_low.S | 335 |
1 files changed, 335 insertions, 0 deletions
diff --git a/arch/powerpc/mm/slb_low.S b/arch/powerpc/mm/slb_low.S new file mode 100644 index 000000000..4ac5057ad --- /dev/null +++ b/arch/powerpc/mm/slb_low.S @@ -0,0 +1,335 @@ +/* + * Low-level SLB routines + * + * Copyright (C) 2004 David Gibson <dwg@au.ibm.com>, IBM + * + * Based on earlier C version: + * Dave Engebretsen and Mike Corrigan {engebret|mikejc}@us.ibm.com + * Copyright (c) 2001 Dave Engebretsen + * Copyright (C) 2002 Anton Blanchard <anton@au.ibm.com>, IBM + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version + * 2 of the License, or (at your option) any later version. + */ + +#include <asm/processor.h> +#include <asm/ppc_asm.h> +#include <asm/asm-offsets.h> +#include <asm/cputable.h> +#include <asm/page.h> +#include <asm/mmu.h> +#include <asm/pgtable.h> +#include <asm/firmware.h> +#include <asm/feature-fixups.h> + +/* + * This macro generates asm code to compute the VSID scramble + * function. Used in slb_allocate() and do_stab_bolted. The function + * computed is: (protovsid*VSID_MULTIPLIER) % VSID_MODULUS + * + * rt = register containing the proto-VSID and into which the + * VSID will be stored + * rx = scratch register (clobbered) + * rf = flags + * + * - rt and rx must be different registers + * - The answer will end up in the low VSID_BITS bits of rt. The higher + * bits may contain other garbage, so you may need to mask the + * result. + */ +#define ASM_VSID_SCRAMBLE(rt, rx, rf, size) \ + lis rx,VSID_MULTIPLIER_##size@h; \ + ori rx,rx,VSID_MULTIPLIER_##size@l; \ + mulld rt,rt,rx; /* rt = rt * MULTIPLIER */ \ +/* \ + * powermac get slb fault before feature fixup, so make 65 bit part \ + * the default part of feature fixup \ + */ \ +BEGIN_MMU_FTR_SECTION \ + srdi rx,rt,VSID_BITS_65_##size; \ + clrldi rt,rt,(64-VSID_BITS_65_##size); \ + add rt,rt,rx; \ + addi rx,rt,1; \ + srdi rx,rx,VSID_BITS_65_##size; \ + add rt,rt,rx; \ + rldimi rf,rt,SLB_VSID_SHIFT_##size,(64 - (SLB_VSID_SHIFT_##size + VSID_BITS_65_##size)); \ +MMU_FTR_SECTION_ELSE \ + srdi rx,rt,VSID_BITS_##size; \ + clrldi rt,rt,(64-VSID_BITS_##size); \ + add rt,rt,rx; /* add high and low bits */ \ + addi rx,rt,1; \ + srdi rx,rx,VSID_BITS_##size; /* extract 2^VSID_BITS bit */ \ + add rt,rt,rx; \ + rldimi rf,rt,SLB_VSID_SHIFT_##size,(64 - (SLB_VSID_SHIFT_##size + VSID_BITS_##size)); \ +ALT_MMU_FTR_SECTION_END_IFCLR(MMU_FTR_68_BIT_VA) + + +/* void slb_allocate(unsigned long ea); + * + * Create an SLB entry for the given EA (user or kernel). + * r3 = faulting address, r13 = PACA + * r9, r10, r11 are clobbered by this function + * r3 is preserved. + * No other registers are examined or changed. + */ +_GLOBAL(slb_allocate) + /* + * Check if the address falls within the range of the first context, or + * if we may need to handle multi context. For the first context we + * allocate the slb entry via the fast path below. For large address we + * branch out to C-code and see if additional contexts have been + * allocated. + * The test here is: + * (ea & ~REGION_MASK) >= (1ull << MAX_EA_BITS_PER_CONTEXT) + */ + rldicr. r9,r3,4,(63 - MAX_EA_BITS_PER_CONTEXT - 4) + bne- 8f + + srdi r9,r3,60 /* get region */ + srdi r10,r3,SID_SHIFT /* get esid */ + cmpldi cr7,r9,0xc /* cmp PAGE_OFFSET for later use */ + + /* r3 = address, r10 = esid, cr7 = <> PAGE_OFFSET */ + blt cr7,0f /* user or kernel? */ + + /* Check if hitting the linear mapping or some other kernel space + */ + bne cr7,1f + + /* Linear mapping encoding bits, the "li" instruction below will + * be patched by the kernel at boot + */ +.globl slb_miss_kernel_load_linear +slb_miss_kernel_load_linear: + li r11,0 + /* + * context = (ea >> 60) - (0xc - 1) + * r9 = region id. + */ + subi r9,r9,KERNEL_REGION_CONTEXT_OFFSET + +BEGIN_FTR_SECTION + b .Lslb_finish_load +END_MMU_FTR_SECTION_IFCLR(MMU_FTR_1T_SEGMENT) + b .Lslb_finish_load_1T + +1: +#ifdef CONFIG_SPARSEMEM_VMEMMAP + cmpldi cr0,r9,0xf + bne 1f +/* Check virtual memmap region. To be patched at kernel boot */ +.globl slb_miss_kernel_load_vmemmap +slb_miss_kernel_load_vmemmap: + li r11,0 + b 6f +1: +#endif /* CONFIG_SPARSEMEM_VMEMMAP */ + + /* + * r10 contains the ESID, which is the original faulting EA shifted + * right by 28 bits. We need to compare that with (H_VMALLOC_END >> 28) + * which is 0xd00038000. That can't be used as an immediate, even if we + * ignored the 0xd, so we have to load it into a register, and we only + * have one register free. So we must load all of (H_VMALLOC_END >> 28) + * into a register and compare ESID against that. + */ + lis r11,(H_VMALLOC_END >> 32)@h // r11 = 0xffffffffd0000000 + ori r11,r11,(H_VMALLOC_END >> 32)@l // r11 = 0xffffffffd0003800 + // Rotate left 4, then mask with 0xffffffff0 + rldic r11,r11,4,28 // r11 = 0xd00038000 + cmpld r10,r11 // if r10 >= r11 + bge 5f // goto io_mapping + + /* + * vmalloc mapping gets the encoding from the PACA as the mapping + * can be demoted from 64K -> 4K dynamically on some machines. + */ + lhz r11,PACAVMALLOCSLLP(r13) + b 6f +5: + /* IO mapping */ +.globl slb_miss_kernel_load_io +slb_miss_kernel_load_io: + li r11,0 +6: + /* + * context = (ea >> 60) - (0xc - 1) + * r9 = region id. + */ + subi r9,r9,KERNEL_REGION_CONTEXT_OFFSET + +BEGIN_FTR_SECTION + b .Lslb_finish_load +END_MMU_FTR_SECTION_IFCLR(MMU_FTR_1T_SEGMENT) + b .Lslb_finish_load_1T + +0: /* + * For userspace addresses, make sure this is region 0. + */ + cmpdi r9, 0 + bne- 8f + /* + * user space make sure we are within the allowed limit + */ + ld r11,PACA_SLB_ADDR_LIMIT(r13) + cmpld r3,r11 + bge- 8f + + /* when using slices, we extract the psize off the slice bitmaps + * and then we need to get the sllp encoding off the mmu_psize_defs + * array. + * + * XXX This is a bit inefficient especially for the normal case, + * so we should try to implement a fast path for the standard page + * size using the old sllp value so we avoid the array. We cannot + * really do dynamic patching unfortunately as processes might flip + * between 4k and 64k standard page size + */ +#ifdef CONFIG_PPC_MM_SLICES + /* r10 have esid */ + cmpldi r10,16 + /* below SLICE_LOW_TOP */ + blt 5f + /* + * Handle hpsizes, + * r9 is get_paca()->context.high_slices_psize[index], r11 is mask_index + */ + srdi r11,r10,(SLICE_HIGH_SHIFT - SLICE_LOW_SHIFT + 1) /* index */ + addi r9,r11,PACAHIGHSLICEPSIZE + lbzx r9,r13,r9 /* r9 is hpsizes[r11] */ + /* r11 = (r10 >> (SLICE_HIGH_SHIFT - SLICE_LOW_SHIFT)) & 0x1 */ + rldicl r11,r10,(64 - (SLICE_HIGH_SHIFT - SLICE_LOW_SHIFT)),63 + b 6f + +5: + /* + * Handle lpsizes + * r9 is get_paca()->context.low_slices_psize[index], r11 is mask_index + */ + srdi r11,r10,1 /* index */ + addi r9,r11,PACALOWSLICESPSIZE + lbzx r9,r13,r9 /* r9 is lpsizes[r11] */ + rldicl r11,r10,0,63 /* r11 = r10 & 0x1 */ +6: + sldi r11,r11,2 /* index * 4 */ + /* Extract the psize and multiply to get an array offset */ + srd r9,r9,r11 + andi. r9,r9,0xf + mulli r9,r9,MMUPSIZEDEFSIZE + + /* Now get to the array and obtain the sllp + */ + ld r11,PACATOC(r13) + ld r11,mmu_psize_defs@got(r11) + add r11,r11,r9 + ld r11,MMUPSIZESLLP(r11) + ori r11,r11,SLB_VSID_USER +#else + /* paca context sllp already contains the SLB_VSID_USER bits */ + lhz r11,PACACONTEXTSLLP(r13) +#endif /* CONFIG_PPC_MM_SLICES */ + + ld r9,PACACONTEXTID(r13) +BEGIN_FTR_SECTION + cmpldi r10,0x1000 + bge .Lslb_finish_load_1T +END_MMU_FTR_SECTION_IFSET(MMU_FTR_1T_SEGMENT) + b .Lslb_finish_load + +8: /* invalid EA - return an error indication */ + crset 4*cr0+eq /* indicate failure */ + blr + +/* + * Finish loading of an SLB entry and return + * + * r3 = EA, r9 = context, r10 = ESID, r11 = flags, clobbers r9, cr7 = <> PAGE_OFFSET + */ +.Lslb_finish_load: + rldimi r10,r9,ESID_BITS,0 + ASM_VSID_SCRAMBLE(r10,r9,r11,256M) + /* r3 = EA, r11 = VSID data */ + /* + * Find a slot, round robin. Previously we tried to find a + * free slot first but that took too long. Unfortunately we + * dont have any LRU information to help us choose a slot. + */ + + mr r9,r3 + + /* slb_finish_load_1T continues here. r9=EA with non-ESID bits clear */ +7: ld r10,PACASTABRR(r13) + addi r10,r10,1 + /* This gets soft patched on boot. */ +.globl slb_compare_rr_to_size +slb_compare_rr_to_size: + cmpldi r10,0 + + blt+ 4f + li r10,SLB_NUM_BOLTED + +4: + std r10,PACASTABRR(r13) + +3: + rldimi r9,r10,0,36 /* r9 = EA[0:35] | entry */ + oris r10,r9,SLB_ESID_V@h /* r10 = r9 | SLB_ESID_V */ + + /* r9 = ESID data, r11 = VSID data */ + + /* + * No need for an isync before or after this slbmte. The exception + * we enter with and the rfid we exit with are context synchronizing. + */ + slbmte r11,r10 + + /* we're done for kernel addresses */ + crclr 4*cr0+eq /* set result to "success" */ + bgelr cr7 + + /* Update the slb cache */ + lhz r9,PACASLBCACHEPTR(r13) /* offset = paca->slb_cache_ptr */ + cmpldi r9,SLB_CACHE_ENTRIES + bge 1f + + /* still room in the slb cache */ + sldi r11,r9,2 /* r11 = offset * sizeof(u32) */ + srdi r10,r10,28 /* get the 36 bits of the ESID */ + add r11,r11,r13 /* r11 = (u32 *)paca + offset */ + stw r10,PACASLBCACHE(r11) /* paca->slb_cache[offset] = esid */ + addi r9,r9,1 /* offset++ */ + b 2f +1: /* offset >= SLB_CACHE_ENTRIES */ + li r9,SLB_CACHE_ENTRIES+1 +2: + sth r9,PACASLBCACHEPTR(r13) /* paca->slb_cache_ptr = offset */ + crclr 4*cr0+eq /* set result to "success" */ + blr + +/* + * Finish loading of a 1T SLB entry (for the kernel linear mapping) and return. + * + * r3 = EA, r9 = context, r10 = ESID(256MB), r11 = flags, clobbers r9 + */ +.Lslb_finish_load_1T: + srdi r10,r10,(SID_SHIFT_1T - SID_SHIFT) /* get 1T ESID */ + rldimi r10,r9,ESID_BITS_1T,0 + ASM_VSID_SCRAMBLE(r10,r9,r11,1T) + + li r10,MMU_SEGSIZE_1T + rldimi r11,r10,SLB_VSID_SSIZE_SHIFT,0 /* insert segment size */ + + /* r3 = EA, r11 = VSID data */ + clrrdi r9,r3,SID_SHIFT_1T /* clear out non-ESID bits */ + b 7b + + +_ASM_NOKPROBE_SYMBOL(slb_allocate) +_ASM_NOKPROBE_SYMBOL(slb_miss_kernel_load_linear) +_ASM_NOKPROBE_SYMBOL(slb_miss_kernel_load_io) +_ASM_NOKPROBE_SYMBOL(slb_compare_rr_to_size) +#ifdef CONFIG_SPARSEMEM_VMEMMAP +_ASM_NOKPROBE_SYMBOL(slb_miss_kernel_load_vmemmap) +#endif |