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authorAndré Fabian Silva Delgado <emulatorman@parabola.nu>2015-08-05 17:04:01 -0300
committerAndré Fabian Silva Delgado <emulatorman@parabola.nu>2015-08-05 17:04:01 -0300
commit57f0f512b273f60d52568b8c6b77e17f5636edc0 (patch)
tree5e910f0e82173f4ef4f51111366a3f1299037a7b /arch/powerpc/mm/slb_low.S
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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>
+
+/* void slb_allocate_realmode(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
+ * No other registers are examined or changed.
+ */
+_GLOBAL(slb_allocate_realmode)
+ /*
+ * check for bad kernel/user address
+ * (ea & ~REGION_MASK) >= PGTABLE_RANGE
+ */
+ rldicr. r9,r3,4,(63 - PGTABLE_EADDR_SIZE - 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? */
+
+ /* kernel address: proto-VSID = ESID */
+ /* WARNING - MAGIC: we don't use the VSID 0xfffffffff, but
+ * this code will generate the protoVSID 0xfffffffff for the
+ * top segment. That's ok, the scramble below will translate
+ * it to VSID 0, which is reserved as a bad VSID - one which
+ * will never have any pages in it. */
+
+ /* 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 = (MAX_USER_CONTEXT) + ((ea >> 60) - 0xc) + 1
+ * r9 = region id.
+ */
+ addis r9,r9,(MAX_USER_CONTEXT - 0xc + 1)@ha
+ addi r9,r9,(MAX_USER_CONTEXT - 0xc + 1)@l
+
+
+BEGIN_FTR_SECTION
+ b slb_finish_load
+END_MMU_FTR_SECTION_IFCLR(MMU_FTR_1T_SEGMENT)
+ b slb_finish_load_1T
+
+1:
+#ifdef CONFIG_SPARSEMEM_VMEMMAP
+ /* Check virtual memmap region. To be patches at kernel boot */
+ cmpldi cr0,r9,0xf
+ bne 1f
+.globl slb_miss_kernel_load_vmemmap
+slb_miss_kernel_load_vmemmap:
+ li r11,0
+ b 6f
+1:
+#endif /* CONFIG_SPARSEMEM_VMEMMAP */
+
+ /* vmalloc mapping gets the encoding from the PACA as the mapping
+ * can be demoted from 64K -> 4K dynamically on some machines
+ */
+ clrldi r11,r10,48
+ cmpldi r11,(VMALLOC_SIZE >> 28) - 1
+ bgt 5f
+ 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 = (MAX_USER_CONTEXT) + ((ea >> 60) - 0xc) + 1
+ * r9 = region id.
+ */
+ addis r9,r9,(MAX_USER_CONTEXT - 0xc + 1)@ha
+ addi r9,r9,(MAX_USER_CONTEXT - 0xc + 1)@l
+
+BEGIN_FTR_SECTION
+ b slb_finish_load
+END_MMU_FTR_SECTION_IFCLR(MMU_FTR_1T_SEGMENT)
+ b slb_finish_load_1T
+
+0:
+ /* 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, r11 is index
+ */
+ ld r9,PACALOWSLICESPSIZE(r13)
+ mr r11,r10
+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 slb_finish_load_1T
+END_MMU_FTR_SECTION_IFSET(MMU_FTR_1T_SEGMENT)
+ b slb_finish_load
+
+8: /* invalid EA */
+ li r10,0 /* BAD_VSID */
+ li r9,0 /* BAD_VSID */
+ li r11,SLB_VSID_USER /* flags don't much matter */
+ b slb_finish_load
+
+#ifdef __DISABLED__
+
+/* void slb_allocate_user(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
+ * No other registers are examined or changed.
+ *
+ * It is called with translation enabled in order to be able to walk the
+ * page tables. This is not currently used.
+ */
+_GLOBAL(slb_allocate_user)
+ /* r3 = faulting address */
+ srdi r10,r3,28 /* get esid */
+
+ crset 4*cr7+lt /* set "user" flag for later */
+
+ /* check if we fit in the range covered by the pagetables*/
+ srdi. r9,r3,PGTABLE_EADDR_SIZE
+ crnot 4*cr0+eq,4*cr0+eq
+ beqlr
+
+ /* now we need to get to the page tables in order to get the page
+ * size encoding from the PMD. In the future, we'll be able to deal
+ * with 1T segments too by getting the encoding from the PGD instead
+ */
+ ld r9,PACAPGDIR(r13)
+ cmpldi cr0,r9,0
+ beqlr
+ rlwinm r11,r10,8,25,28
+ ldx r9,r9,r11 /* get pgd_t */
+ cmpldi cr0,r9,0
+ beqlr
+ rlwinm r11,r10,3,17,28
+ ldx r9,r9,r11 /* get pmd_t */
+ cmpldi cr0,r9,0
+ beqlr
+
+ /* build vsid flags */
+ andi. r11,r9,SLB_VSID_LLP
+ ori r11,r11,SLB_VSID_USER
+
+ /* get context to calculate proto-VSID */
+ ld r9,PACACONTEXTID(r13)
+ /* fall through slb_finish_load */
+
+#endif /* __DISABLED__ */
+
+
+/*
+ * Finish loading of an SLB entry and return
+ *
+ * r3 = EA, r9 = context, r10 = ESID, r11 = flags, clobbers r9, cr7 = <> PAGE_OFFSET
+ */
+slb_finish_load:
+ rldimi r10,r9,ESID_BITS,0
+ ASM_VSID_SCRAMBLE(r10,r9,256M)
+ /*
+ * bits above VSID_BITS_256M need to be ignored from r10
+ * also combine VSID and flags
+ */
+ rldimi r11,r10,SLB_VSID_SHIFT,(64 - (SLB_VSID_SHIFT + VSID_BITS_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.
+ */
+
+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 r3,r10,0,36 /* r3= EA[0:35] | entry */
+ oris r10,r3,SLB_ESID_V@h /* r3 |= SLB_ESID_V */
+
+ /* r3 = 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 r3,PACASLBCACHEPTR(r13) /* offset = paca->slb_cache_ptr */
+ cmpldi r3,SLB_CACHE_ENTRIES
+ bge 1f
+
+ /* still room in the slb cache */
+ sldi r11,r3,2 /* 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 r3,r3,1 /* offset++ */
+ b 2f
+1: /* offset >= SLB_CACHE_ENTRIES */
+ li r3,SLB_CACHE_ENTRIES+1
+2:
+ sth r3,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
+ */
+slb_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,r9,1T)
+ /*
+ * bits above VSID_BITS_1T need to be ignored from r10
+ * also combine VSID and flags
+ */
+ rldimi r11,r10,SLB_VSID_SHIFT_1T,(64 - (SLB_VSID_SHIFT_1T + VSID_BITS_1T))
+ li r10,MMU_SEGSIZE_1T
+ rldimi r11,r10,SLB_VSID_SSIZE_SHIFT,0 /* insert segment size */
+
+ /* r3 = EA, r11 = VSID data */
+ clrrdi r3,r3,SID_SHIFT_1T /* clear out non-ESID bits */
+ b 7b
+