powerpc: Remove STAB code

Old cpus didn't have a Segment Lookaside Buffer (SLB), instead they had
a Segment Table (STAB). Now that we've dropped support for those cpus,
we can remove the STAB support entirely.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

12 files changed, 11 insertions, 522 deletions

diff --git a/arch/powerpc/include/asm/mmu-hash64.h b/arch/powerpc/include/asm/mmu-hash64.h
index c2b4dcf23d03..d76514487d6f 100644
--- a/arch/powerpc/include/asm/mmu-hash64.h
+++ b/arch/powerpc/include/asm/mmu-hash64.h
@@ -25,26 +25,6 @@
 #include <asm/processor.h>
 
 /*
- * Segment table
- */
-
-#define STE_ESID_V      0x80
-#define STE_ESID_KS     0x20
-#define STE_ESID_KP     0x10
-#define STE_ESID_N      0x08
-
-#define STE_VSID_SHIFT  12
-
-/* Location of cpu0's segment table */
-#define STAB0_PAGE      0x8
-#define STAB0_OFFSET    (STAB0_PAGE << 12)
-#define STAB0_PHYS_ADDR (STAB0_OFFSET + PHYSICAL_START)
-
-#ifndef __ASSEMBLY__
-extern char initial_stab[];
-#endif /* ! __ASSEMBLY */
-
-/*
  * SLB
  */
 
@@ -370,10 +350,8 @@ extern void hpte_init_lpar(void);
 extern void hpte_init_beat(void);
 extern void hpte_init_beat_v3(void);
 
-extern void stabs_alloc(void);
 extern void slb_initialize(void);
 extern void slb_flush_and_rebolt(void);
-extern void stab_initialize(unsigned long stab);
 
 extern void slb_vmalloc_update(void);
 extern void slb_set_size(u16 size);
diff --git a/arch/powerpc/include/asm/mmu_context.h b/arch/powerpc/include/asm/mmu_context.h
index b467530e2485..f5690e2689c7 100644
--- a/arch/powerpc/include/asm/mmu_context.h
+++ b/arch/powerpc/include/asm/mmu_context.h
@@ -18,7 +18,6 @@ extern int init_new_context(struct task_struct *tsk, struct mm_struct *mm);
 extern void destroy_context(struct mm_struct *mm);
 
 extern void switch_mmu_context(struct mm_struct *prev, struct mm_struct *next);
-extern void switch_stab(struct task_struct *tsk, struct mm_struct *mm);
 extern void switch_slb(struct task_struct *tsk, struct mm_struct *mm);
 extern void set_context(unsigned long id, pgd_t *pgd);
 
@@ -79,8 +78,6 @@ static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next,
 #ifdef CONFIG_PPC_STD_MMU_64
         if (mmu_has_feature(MMU_FTR_SLB))
                 switch_slb(tsk, next);
-        else
-                switch_stab(tsk, next);
 #else
         /* Out of line for now */
         switch_mmu_context(prev, next);
diff --git a/arch/powerpc/include/asm/paca.h b/arch/powerpc/include/asm/paca.h
index bb0bd25f20d0..5abde4e223bb 100644
--- a/arch/powerpc/include/asm/paca.h
+++ b/arch/powerpc/include/asm/paca.h
@@ -78,10 +78,6 @@ struct paca_struct {
         u64 kernel_toc;                 /* Kernel TOC address */
         u64 kernelbase;                 /* Base address of kernel */
         u64 kernel_msr;                 /* MSR while running in kernel */
-#ifdef CONFIG_PPC_STD_MMU_64
-        u64 stab_real;                  /* Absolute address of segment table */
-        u64 stab_addr;                  /* Virtual address of segment table */
-#endif /* CONFIG_PPC_STD_MMU_64 */
         void *emergency_sp;             /* pointer to emergency stack */
         u64 data_offset;                /* per cpu data offset */
         s16 hw_cpu_id;                  /* Physical processor number */
diff --git a/arch/powerpc/include/asm/reg.h b/arch/powerpc/include/asm/reg.h
index bffd89d27301..f7b97b895708 100644
--- a/arch/powerpc/include/asm/reg.h
+++ b/arch/powerpc/include/asm/reg.h
@@ -254,7 +254,7 @@
 #define   DSISR_PROTFAULT       0x08000000      /* protection fault */
 #define   DSISR_ISSTORE         0x02000000      /* access was a store */
 #define   DSISR_DABRMATCH       0x00400000      /* hit data breakpoint */
-#define   DSISR_NOSEGMENT       0x00200000      /* STAB/SLB miss */
+#define   DSISR_NOSEGMENT       0x00200000      /* SLB miss */
 #define   DSISR_KEYFAULT        0x00200000      /* Key fault */
 #define SPRN_TBRL       0x10C   /* Time Base Read Lower Register (user, R/O) */
 #define SPRN_TBRU       0x10D   /* Time Base Read Upper Register (user, R/O) */
diff --git a/arch/powerpc/kernel/asm-offsets.c b/arch/powerpc/kernel/asm-offsets.c
index f5995a912213..e35054054c32 100644
--- a/arch/powerpc/kernel/asm-offsets.c
+++ b/arch/powerpc/kernel/asm-offsets.c
@@ -216,8 +216,6 @@ int main(void)
 #endif /* CONFIG_PPC_BOOK3E */
 
 #ifdef CONFIG_PPC_STD_MMU_64
-        DEFINE(PACASTABREAL, offsetof(struct paca_struct, stab_real));
-        DEFINE(PACASTABVIRT, offsetof(struct paca_struct, stab_addr));
         DEFINE(PACASLBCACHE, offsetof(struct paca_struct, slb_cache));
         DEFINE(PACASLBCACHEPTR, offsetof(struct paca_struct, slb_cache_ptr));
         DEFINE(PACAVMALLOCSLLP, offsetof(struct paca_struct, vmalloc_sllp));
diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S
index a7d36b19221d..b859b3665be6 100644
--- a/arch/powerpc/kernel/exceptions-64s.S
+++ b/arch/powerpc/kernel/exceptions-64s.S
@@ -188,10 +188,6 @@ ALT_FTR_SECTION_END_IFSET(CPU_FTR_HVMODE)
 data_access_pSeries:
         HMT_MEDIUM_PPR_DISCARD
         SET_SCRATCH0(r13)
-BEGIN_FTR_SECTION
-        b       data_access_check_stab
-data_access_not_stab:
-END_MMU_FTR_SECTION_IFCLR(MMU_FTR_SLB)
         EXCEPTION_PROLOG_PSERIES(PACA_EXGEN, data_access_common, EXC_STD,
                                  KVMTEST, 0x300)
 
@@ -514,34 +510,6 @@ machine_check_pSeries_0:
         EXCEPTION_PROLOG_1(PACA_EXMC, KVMTEST, 0x200)
         EXCEPTION_PROLOG_PSERIES_1(machine_check_common, EXC_STD)
         KVM_HANDLER_SKIP(PACA_EXMC, EXC_STD, 0x200)
-
-        /* moved from 0x300 */
-data_access_check_stab:
-        GET_PACA(r13)
-        std     r9,PACA_EXSLB+EX_R9(r13)
-        std     r10,PACA_EXSLB+EX_R10(r13)
-        mfspr   r10,SPRN_DAR
-        mfspr   r9,SPRN_DSISR
-        srdi    r10,r10,60
-        rlwimi  r10,r9,16,0x20
-#ifdef CONFIG_KVM_BOOK3S_PR_POSSIBLE
-        lbz     r9,HSTATE_IN_GUEST(r13)
-        rlwimi  r10,r9,8,0x300
-#endif
-        mfcr    r9
-        cmpwi   r10,0x2c
-        beq     do_stab_bolted_pSeries
-        mtcrf   0x80,r9
-        ld      r9,PACA_EXSLB+EX_R9(r13)
-        ld      r10,PACA_EXSLB+EX_R10(r13)
-        b       data_access_not_stab
-do_stab_bolted_pSeries:
-        std     r11,PACA_EXSLB+EX_R11(r13)
-        std     r12,PACA_EXSLB+EX_R12(r13)
-        GET_SCRATCH0(r10)
-        std     r10,PACA_EXSLB+EX_R13(r13)
-        EXCEPTION_PROLOG_PSERIES_1(do_stab_bolted, EXC_STD)
-
         KVM_HANDLER_SKIP(PACA_EXGEN, EXC_STD, 0x300)
         KVM_HANDLER_SKIP(PACA_EXSLB, EXC_STD, 0x380)
         KVM_HANDLER_PR(PACA_EXGEN, EXC_STD, 0x400)
@@ -1338,12 +1306,6 @@ fwnmi_data_area:
         . = 0x8000
 #endif /* defined(CONFIG_PPC_PSERIES) || defined(CONFIG_PPC_POWERNV) */
 
-/* Space for CPU0's segment table */
-        .balign 4096
-        .globl initial_stab
-initial_stab:
-        .space  4096
-
 #ifdef CONFIG_PPC_POWERNV
 _GLOBAL(opal_mc_secondary_handler)
         HMT_MEDIUM_PPR_DISCARD
@@ -1594,12 +1556,6 @@ do_hash_page:
         bne-    handle_page_fault       /* if not, try to insert a HPTE */
         andis.  r0,r4,DSISR_DABRMATCH@h
         bne-    handle_dabr_fault
-
-BEGIN_FTR_SECTION
-        andis.  r0,r4,0x0020            /* Is it a segment table fault? */
-        bne-    do_ste_alloc            /* If so handle it */
-END_MMU_FTR_SECTION_IFCLR(MMU_FTR_SLB)
-
         CURRENT_THREAD_INFO(r11, r1)
         lwz     r0,TI_PREEMPT(r11)      /* If we're in an "NMI" */
         andis.  r0,r0,NMI_MASK@h        /* (i.e. an irq when soft-disabled) */
@@ -1680,114 +1636,3 @@ handle_dabr_fault:
         li      r5,SIGSEGV
         bl      bad_page_fault
         b       ret_from_except
-
-        /* here we have a segment miss */
-do_ste_alloc:
-        bl      ste_allocate            /* try to insert stab entry */
-        cmpdi   r3,0
-        bne-    handle_page_fault
-        b       fast_exception_return
-
-/*
- * r13 points to the PACA, r9 contains the saved CR,
- * r11 and r12 contain the saved SRR0 and SRR1.
- * r9 - r13 are saved in paca->exslb.
- * We assume we aren't going to take any exceptions during this procedure.
- * We assume (DAR >> 60) == 0xc.
- */
-        .align  7
-do_stab_bolted:
-        stw     r9,PACA_EXSLB+EX_CCR(r13)       /* save CR in exc. frame */
-        std     r11,PACA_EXSLB+EX_SRR0(r13)     /* save SRR0 in exc. frame */
-        mfspr   r11,SPRN_DAR                    /* ea */
-
-        /*
-         * check for bad kernel/user address
-         * (ea & ~REGION_MASK) >= PGTABLE_RANGE
-         */
-        rldicr. r9,r11,4,(63 - 46 - 4)
-        li      r9,0    /* VSID = 0 for bad address */
-        bne-    0f
-
-        /*
-         * Calculate VSID:
-         * This is the kernel vsid, we take the top for context from
-         * the range. context = (MAX_USER_CONTEXT) + ((ea >> 60) - 0xc) + 1
-         * Here we know that (ea >> 60) == 0xc
-         */
-        lis     r9,(MAX_USER_CONTEXT + 1)@ha
-        addi    r9,r9,(MAX_USER_CONTEXT + 1)@l
-
-        srdi    r10,r11,SID_SHIFT
-        rldimi  r10,r9,ESID_BITS,0 /* proto vsid */
-        ASM_VSID_SCRAMBLE(r10, r9, 256M)
-        rldic   r9,r10,12,16    /* r9 = vsid << 12 */
-
-0:
-        /* Hash to the primary group */
-        ld      r10,PACASTABVIRT(r13)
-        srdi    r11,r11,SID_SHIFT
-        rldimi  r10,r11,7,52    /* r10 = first ste of the group */
-
-        /* Search the primary group for a free entry */
-1:      ld      r11,0(r10)      /* Test valid bit of the current ste    */
-        andi.   r11,r11,0x80
-        beq     2f
-        addi    r10,r10,16
-        andi.   r11,r10,0x70
-        bne     1b
-
-        /* Stick for only searching the primary group for now.          */
-        /* At least for now, we use a very simple random castout scheme */
-        /* Use the TB as a random number ;  OR in 1 to avoid entry 0    */
-        mftb    r11
-        rldic   r11,r11,4,57    /* r11 = (r11 << 4) & 0x70 */
-        ori     r11,r11,0x10
-
-        /* r10 currently points to an ste one past the group of interest */
-        /* make it point to the randomly selected entry                 */
-        subi    r10,r10,128
-        or      r10,r10,r11     /* r10 is the entry to invalidate       */
-
-        isync                   /* mark the entry invalid               */
-        ld      r11,0(r10)
-        rldicl  r11,r11,56,1    /* clear the valid bit */
-        rotldi  r11,r11,8
-        std     r11,0(r10)
-        sync
-
-        clrrdi  r11,r11,28      /* Get the esid part of the ste         */
-        slbie   r11
-
-2:      std     r9,8(r10)       /* Store the vsid part of the ste       */
-        eieio
-
-        mfspr   r11,SPRN_DAR            /* Get the new esid                     */
-        clrrdi  r11,r11,28      /* Permits a full 32b of ESID           */
-        ori     r11,r11,0x90    /* Turn on valid and kp                 */
-        std     r11,0(r10)      /* Put new entry back into the stab     */
-
-        sync
-
-        /* All done -- return from exception. */
-        lwz     r9,PACA_EXSLB+EX_CCR(r13)       /* get saved CR */
-        ld      r11,PACA_EXSLB+EX_SRR0(r13)     /* get saved SRR0 */
-
-        andi.   r10,r12,MSR_RI
-        beq-    unrecov_slb
-
-        mtcrf   0x80,r9                 /* restore CR */
-
-        mfmsr   r10
-        clrrdi  r10,r10,2
-        mtmsrd  r10,1
-
-        mtspr   SPRN_SRR0,r11
-        mtspr   SPRN_SRR1,r12
-        ld      r9,PACA_EXSLB+EX_R9(r13)
-        ld      r10,PACA_EXSLB+EX_R10(r13)
-        ld      r11,PACA_EXSLB+EX_R11(r13)
-        ld      r12,PACA_EXSLB+EX_R12(r13)
-        ld      r13,PACA_EXSLB+EX_R13(r13)
-        rfid
-        b       .       /* prevent speculative execution */
diff --git a/arch/powerpc/kernel/head_64.S b/arch/powerpc/kernel/head_64.S
index a95145d7f61b..41ab76c3a94a 100644
--- a/arch/powerpc/kernel/head_64.S
+++ b/arch/powerpc/kernel/head_64.S
@@ -618,7 +618,7 @@ __secondary_start:
         addi    r14,r14,THREAD_SIZE-STACK_FRAME_OVERHEAD
         std     r14,PACAKSAVE(r13)
 
-        /* Do early setup for that CPU (stab, slb, hash table pointer) */
+        /* Do early setup for that CPU (SLB and hash table pointer) */
         bl      early_setup_secondary
 
         /*
@@ -771,8 +771,10 @@ start_here_multiplatform:
         li      r0,0
         stdu    r0,-STACK_FRAME_OVERHEAD(r1)
 
-        /* Do very early kernel initializations, including initial hash table,
-         * stab and slb setup before we turn on relocation.     */
+        /*
+         * Do very early kernel initializations, including initial hash table
+         * and SLB setup before we turn on relocation.
+         */
 
         /* Restore parameters passed from prom_init/kexec */
         mr      r3,r31
diff --git a/arch/powerpc/kernel/setup_64.c b/arch/powerpc/kernel/setup_64.c
index ee082d771178..694339043b56 100644
--- a/arch/powerpc/kernel/setup_64.c
+++ b/arch/powerpc/kernel/setup_64.c
@@ -673,9 +673,6 @@ void __init setup_arch(char **cmdline_p)
         exc_lvl_early_init();
         emergency_stack_init();
 
-#ifdef CONFIG_PPC_STD_MMU_64
-        stabs_alloc();
-#endif
         /* set up the bootmem stuff with available memory */
         do_init_bootmem();
         sparse_init();
diff --git a/arch/powerpc/mm/Makefile b/arch/powerpc/mm/Makefile
index 51230ee6a407..d0130fff20e5 100644
--- a/arch/powerpc/mm/Makefile
+++ b/arch/powerpc/mm/Makefile
@@ -13,9 +13,7 @@ obj-$(CONFIG_PPC_MMU_NOHASH)	+= mmu_context_nohash.o tlb_nohash.o \
                                    tlb_nohash_low.o
 obj-$(CONFIG_PPC_BOOK3E)        += tlb_low_$(CONFIG_WORD_SIZE)e.o
 hash64-$(CONFIG_PPC_NATIVE)     := hash_native_64.o
-obj-$(CONFIG_PPC_STD_MMU_64)    += hash_utils_64.o \
-                                   slb_low.o slb.o stab.o \
-                                   $(hash64-y)
+obj-$(CONFIG_PPC_STD_MMU_64)    += hash_utils_64.o slb_low.o slb.o $(hash64-y)
 obj-$(CONFIG_PPC_STD_MMU_32)    += ppc_mmu_32.o
 obj-$(CONFIG_PPC_STD_MMU)       += hash_low_$(CONFIG_WORD_SIZE).o \
                                    tlb_hash$(CONFIG_WORD_SIZE).o \
diff --git a/arch/powerpc/mm/hash_utils_64.c b/arch/powerpc/mm/hash_utils_64.c
index 88fdd9d25077..fb8bea71327d 100644
--- a/arch/powerpc/mm/hash_utils_64.c
+++ b/arch/powerpc/mm/hash_utils_64.c
@@ -821,21 +821,15 @@ static void __init htab_initialize(void)
 
 void __init early_init_mmu(void)
 {
-        /* Setup initial STAB address in the PACA */
-        get_paca()->stab_real = __pa((u64)&initial_stab);
-        get_paca()->stab_addr = (u64)&initial_stab;
-
         /* Initialize the MMU Hash table and create the linear mapping
-         * of memory. Has to be done before stab/slb initialization as
-         * this is currently where the page size encoding is obtained
+         * of memory. Has to be done before SLB initialization as this is
+         * currently where the page size encoding is obtained.
          */
         htab_initialize();
 
-        /* Initialize stab / SLB management */
+        /* Initialize SLB management */
         if (mmu_has_feature(MMU_FTR_SLB))
                 slb_initialize();
-        else
-                stab_initialize(get_paca()->stab_real);
 }
 
 #ifdef CONFIG_SMP
@@ -845,13 +839,9 @@ void early_init_mmu_secondary(void)
         if (!firmware_has_feature(FW_FEATURE_LPAR))
                 mtspr(SPRN_SDR1, _SDR1);
 
-        /* Initialize STAB/SLB. We use a virtual address as it works
-         * in real mode on pSeries.
-         */
+        /* Initialize SLB */
         if (mmu_has_feature(MMU_FTR_SLB))
                 slb_initialize();
-        else
-                stab_initialize(get_paca()->stab_addr);
 }
 #endif /* CONFIG_SMP */
 
diff --git a/arch/powerpc/mm/stab.c b/arch/powerpc/mm/stab.c
deleted file mode 100644
index 3f8efa6f2997..000000000000
--- a/arch/powerpc/mm/stab.c
+++ /dev/null
@@ -1,286 +0,0 @@
-/*
- * PowerPC64 Segment Translation Support.
- *
- * 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 <linux/memblock.h>
-
-#include <asm/pgtable.h>
-#include <asm/mmu.h>
-#include <asm/mmu_context.h>
-#include <asm/paca.h>
-#include <asm/cputable.h>
-#include <asm/prom.h>
-
-struct stab_entry {
-        unsigned long esid_data;
-        unsigned long vsid_data;
-};
-
-#define NR_STAB_CACHE_ENTRIES 8
-static DEFINE_PER_CPU(long, stab_cache_ptr);
-static DEFINE_PER_CPU(long [NR_STAB_CACHE_ENTRIES], stab_cache);
-
-/*
- * Create a segment table entry for the given esid/vsid pair.
- */
-static int make_ste(unsigned long stab, unsigned long esid, unsigned long vsid)
-{
-        unsigned long esid_data, vsid_data;
-        unsigned long entry, group, old_esid, castout_entry, i;
-        unsigned int global_entry;
-        struct stab_entry *ste, *castout_ste;
-        unsigned long kernel_segment = (esid << SID_SHIFT) >= PAGE_OFFSET;
-
-        vsid_data = vsid << STE_VSID_SHIFT;
-        esid_data = esid << SID_SHIFT | STE_ESID_KP | STE_ESID_V;
-        if (! kernel_segment)
-                esid_data |= STE_ESID_KS;
-
-        /* Search the primary group first. */
-        global_entry = (esid & 0x1f) << 3;
-        ste = (struct stab_entry *)(stab | ((esid & 0x1f) << 7));
-
-        /* Find an empty entry, if one exists. */
-        for (group = 0; group < 2; group++) {
-                for (entry = 0; entry < 8; entry++, ste++) {
-                        if (!(ste->esid_data & STE_ESID_V)) {
-                                ste->vsid_data = vsid_data;
-                                eieio();
-                                ste->esid_data = esid_data;
-                                return (global_entry | entry);
-                        }
-                }
-                /* Now search the secondary group. */
-                global_entry = ((~esid) & 0x1f) << 3;
-                ste = (struct stab_entry *)(stab | (((~esid) & 0x1f) << 7));
-        }
-
-        /*
-         * Could not find empty entry, pick one with a round robin selection.
-         * Search all entries in the two groups.
-         */
-        castout_entry = get_paca()->stab_rr;
-        for (i = 0; i < 16; i++) {
-                if (castout_entry < 8) {
-                        global_entry = (esid & 0x1f) << 3;
-                        ste = (struct stab_entry *)(stab | ((esid & 0x1f) << 7));
-                        castout_ste = ste + castout_entry;
-                } else {
-                        global_entry = ((~esid) & 0x1f) << 3;
-                        ste = (struct stab_entry *)(stab | (((~esid) & 0x1f) << 7));
-                        castout_ste = ste + (castout_entry - 8);
-                }
-
-                /* Dont cast out the first kernel segment */
-                if ((castout_ste->esid_data & ESID_MASK) != PAGE_OFFSET)
-                        break;
-
-                castout_entry = (castout_entry + 1) & 0xf;
-        }
-
-        get_paca()->stab_rr = (castout_entry + 1) & 0xf;
-
-        /* Modify the old entry to the new value. */
-
-        /* Force previous translations to complete. DRENG */
-        asm volatile("isync" : : : "memory");
-
-        old_esid = castout_ste->esid_data >> SID_SHIFT;
-        castout_ste->esid_data = 0;             /* Invalidate old entry */
-
-        asm volatile("sync" : : : "memory");    /* Order update */
-
-        castout_ste->vsid_data = vsid_data;
-        eieio();                                /* Order update */
-        castout_ste->esid_data = esid_data;
-
-        asm volatile("slbie  %0" : : "r" (old_esid << SID_SHIFT));
-        /* Ensure completion of slbie */
-        asm volatile("sync" : : : "memory");
-
-        return (global_entry | (castout_entry & 0x7));
-}
-
-/*
- * Allocate a segment table entry for the given ea and mm
- */
-static int __ste_allocate(unsigned long ea, struct mm_struct *mm)
-{
-        unsigned long vsid;
-        unsigned char stab_entry;
-        unsigned long offset;
-
-        /* Kernel or user address? */
-        if (is_kernel_addr(ea)) {
-                vsid = get_kernel_vsid(ea, MMU_SEGSIZE_256M);
-        } else {
-                if ((ea >= TASK_SIZE_USER64) || (! mm))
-                        return 1;
-
-                vsid = get_vsid(mm->context.id, ea, MMU_SEGSIZE_256M);
-        }
-
-        stab_entry = make_ste(get_paca()->stab_addr, GET_ESID(ea), vsid);
-
-        if (!is_kernel_addr(ea)) {
-                offset = __get_cpu_var(stab_cache_ptr);
-                if (offset < NR_STAB_CACHE_ENTRIES)
-                        __get_cpu_var(stab_cache[offset++]) = stab_entry;
-                else
-                        offset = NR_STAB_CACHE_ENTRIES+1;
-                __get_cpu_var(stab_cache_ptr) = offset;
-
-                /* Order update */
-                asm volatile("sync":::"memory");
-        }
-
-        return 0;
-}
-
-int ste_allocate(unsigned long ea)
-{
-        return __ste_allocate(ea, current->mm);
-}
-
-/*
- * Do the segment table work for a context switch: flush all user
- * entries from the table, then preload some probably useful entries
- * for the new task
- */
-void switch_stab(struct task_struct *tsk, struct mm_struct *mm)
-{
-        struct stab_entry *stab = (struct stab_entry *) get_paca()->stab_addr;
-        struct stab_entry *ste;
-        unsigned long offset;
-        unsigned long pc = KSTK_EIP(tsk);
-        unsigned long stack = KSTK_ESP(tsk);
-        unsigned long unmapped_base;
-
-        /* Force previous translations to complete. DRENG */
-        asm volatile("isync" : : : "memory");
-
-        /*
-         * We need interrupts hard-disabled here, not just soft-disabled,
-         * so that a PMU interrupt can't occur, which might try to access
-         * user memory (to get a stack trace) and possible cause an STAB miss
-         * which would update the stab_cache/stab_cache_ptr per-cpu variables.
-         */
-        hard_irq_disable();
-
-        offset = __get_cpu_var(stab_cache_ptr);
-        if (offset <= NR_STAB_CACHE_ENTRIES) {
-                int i;
-
-                for (i = 0; i < offset; i++) {
-                        ste = stab + __get_cpu_var(stab_cache[i]);
-                        ste->esid_data = 0; /* invalidate entry */
-                }
-        } else {
-                unsigned long entry;
-
-                /* Invalidate all entries. */
-                ste = stab;
-
-                /* Never flush the first entry. */
-                ste += 1;
-                for (entry = 1;
-                     entry < (HW_PAGE_SIZE / sizeof(struct stab_entry));
-                     entry++, ste++) {
-                        unsigned long ea;
-                        ea = ste->esid_data & ESID_MASK;
-                        if (!is_kernel_addr(ea)) {
-                                ste->esid_data = 0;
-                        }
-                }
-        }
-
-        asm volatile("sync; slbia; sync":::"memory");
-
-        __get_cpu_var(stab_cache_ptr) = 0;
-
-        /* Now preload some entries for the new task */
-        if (test_tsk_thread_flag(tsk, TIF_32BIT))
-                unmapped_base = TASK_UNMAPPED_BASE_USER32;
-        else
-                unmapped_base = TASK_UNMAPPED_BASE_USER64;
-
-        __ste_allocate(pc, mm);
-
-        if (GET_ESID(pc) == GET_ESID(stack))
-                return;
-
-        __ste_allocate(stack, mm);
-
-        if ((GET_ESID(pc) == GET_ESID(unmapped_base))
-            || (GET_ESID(stack) == GET_ESID(unmapped_base)))
-                return;
-
-        __ste_allocate(unmapped_base, mm);
-
-        /* Order update */
-        asm volatile("sync" : : : "memory");
-}
-
-/*
- * Allocate segment tables for secondary CPUs.  These must all go in
- * the first (bolted) segment, so that do_stab_bolted won't get a
- * recursive segment miss on the segment table itself.
- */
-void __init stabs_alloc(void)
-{
-        int cpu;
-
-        if (mmu_has_feature(MMU_FTR_SLB))
-                return;
-
-        for_each_possible_cpu(cpu) {
-                unsigned long newstab;
-
-                if (cpu == 0)
-                        continue; /* stab for CPU 0 is statically allocated */
-
-                newstab = memblock_alloc_base(HW_PAGE_SIZE, HW_PAGE_SIZE,
-                                         1<<SID_SHIFT);
-                newstab = (unsigned long)__va(newstab);
-
-                memset((void *)newstab, 0, HW_PAGE_SIZE);
-
-                paca[cpu].stab_addr = newstab;
-                paca[cpu].stab_real = __pa(newstab);
-                printk(KERN_INFO "Segment table for CPU %d at 0x%llx "
-                       "virtual, 0x%llx absolute\n",
-                       cpu, paca[cpu].stab_addr, paca[cpu].stab_real);
-        }
-}
-
-/*
- * Build an entry for the base kernel segment and put it into
- * the segment table or SLB.  All other segment table or SLB
- * entries are faulted in.
- */
-void stab_initialize(unsigned long stab)
-{
-        unsigned long vsid = get_kernel_vsid(PAGE_OFFSET, MMU_SEGSIZE_256M);
-        unsigned long stabreal;
-
-        asm volatile("isync; slbia; isync":::"memory");
-        make_ste(stab, GET_ESID(PAGE_OFFSET), vsid);
-
-        /* Order update */
-        asm volatile("sync":::"memory");
-
-        /* Set ASR */
-        stabreal = get_paca()->stab_real | 0x1ul;
-
-        mtspr(SPRN_ASR, stabreal);
-}
diff --git a/arch/powerpc/xmon/xmon.c b/arch/powerpc/xmon/xmon.c
index d199bfa2f1fa..dc8cf285c3ff 100644
--- a/arch/powerpc/xmon/xmon.c
+++ b/arch/powerpc/xmon/xmon.c
@@ -2058,10 +2058,6 @@ static void dump_one_paca(int cpu)
         DUMP(p, kernel_toc, "lx");
         DUMP(p, kernelbase, "lx");
         DUMP(p, kernel_msr, "lx");
-#ifdef CONFIG_PPC_STD_MMU_64
-        DUMP(p, stab_real, "lx");
-        DUMP(p, stab_addr, "lx");
-#endif
         DUMP(p, emergency_sp, "p");
 #ifdef CONFIG_PPC_BOOK3S_64
         DUMP(p, mc_emergency_sp, "p");
@@ -2727,32 +2723,10 @@ static void dump_slb(void)
         }
 }
 
-static void dump_stab(void)
-{
-        int i;
-        unsigned long *tmp = (unsigned long *)local_paca->stab_addr;
-
-        printf("Segment table contents of cpu 0x%x\n", smp_processor_id());
-
-        for (i = 0; i < PAGE_SIZE/16; i++) {
-                unsigned long a, b;
-
-                a = *tmp++;
-                b = *tmp++;
-
-                if (a || b) {
-                        printf("%03d %016lx ", i, a);
-                        printf("%016lx\n", b);
-                }
-        }
-}
-
 void dump_segments(void)
 {
         if (mmu_has_feature(MMU_FTR_SLB))
                 dump_slb();
-        else
-                dump_stab();
 }
 #endif