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- /*
- * 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
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