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Diffstat (limited to 'arch/powerpc/mm/book3s32/hash_low.S')
| -rw-r--r-- | arch/powerpc/mm/book3s32/hash_low.S | 598 |
1 files changed, 598 insertions, 0 deletions
diff --git a/arch/powerpc/mm/book3s32/hash_low.S b/arch/powerpc/mm/book3s32/hash_low.S new file mode 100644 index 000000000..6925ce998 --- /dev/null +++ b/arch/powerpc/mm/book3s32/hash_low.S @@ -0,0 +1,598 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +/* + * PowerPC version + * Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org) + * Rewritten by Cort Dougan (cort@cs.nmt.edu) for PReP + * Copyright (C) 1996 Cort Dougan <cort@cs.nmt.edu> + * Adapted for Power Macintosh by Paul Mackerras. + * Low-level exception handlers and MMU support + * rewritten by Paul Mackerras. + * Copyright (C) 1996 Paul Mackerras. + * + * This file contains low-level assembler routines for managing + * the PowerPC MMU hash table. (PPC 8xx processors don't use a + * hash table, so this file is not used on them.) + */ + +#include <linux/pgtable.h> +#include <linux/init.h> +#include <asm/reg.h> +#include <asm/page.h> +#include <asm/cputable.h> +#include <asm/ppc_asm.h> +#include <asm/thread_info.h> +#include <asm/asm-offsets.h> +#include <asm/export.h> +#include <asm/feature-fixups.h> +#include <asm/code-patching-asm.h> + +#ifdef CONFIG_PTE_64BIT +#define PTE_T_SIZE 8 +#define PTE_FLAGS_OFFSET 4 /* offset of PTE flags, in bytes */ +#else +#define PTE_T_SIZE 4 +#define PTE_FLAGS_OFFSET 0 +#endif + +/* + * Load a PTE into the hash table, if possible. + * The address is in r4, and r3 contains an access flag: + * _PAGE_RW (0x400) if a write. + * r9 contains the SRR1 value, from which we use the MSR_PR bit. + * SPRG_THREAD contains the physical address of the current task's thread. + * + * Returns to the caller if the access is illegal or there is no + * mapping for the address. Otherwise it places an appropriate PTE + * in the hash table and returns from the exception. + * Uses r0, r3 - r6, r8, r10, ctr, lr. + */ + .text +_GLOBAL(hash_page) +#ifdef CONFIG_SMP + lis r8, (mmu_hash_lock - PAGE_OFFSET)@h + ori r8, r8, (mmu_hash_lock - PAGE_OFFSET)@l + lis r0,0x0fff + b 10f +11: lwz r6,0(r8) + cmpwi 0,r6,0 + bne 11b +10: lwarx r6,0,r8 + cmpwi 0,r6,0 + bne- 11b + stwcx. r0,0,r8 + bne- 10b + isync +#endif + /* Get PTE (linux-style) and check access */ + lis r0, TASK_SIZE@h /* check if kernel address */ + cmplw 0,r4,r0 + mfspr r8,SPRN_SPRG_THREAD /* current task's THREAD (phys) */ + ori r3,r3,_PAGE_USER|_PAGE_PRESENT /* test low addresses as user */ + lwz r5,PGDIR(r8) /* virt page-table root */ + blt+ 112f /* assume user more likely */ + lis r5,swapper_pg_dir@ha /* if kernel address, use */ + addi r5,r5,swapper_pg_dir@l /* kernel page table */ + rlwimi r3,r9,32-12,29,29 /* MSR_PR -> _PAGE_USER */ +112: tophys(r5, r5) +#ifndef CONFIG_PTE_64BIT + rlwimi r5,r4,12,20,29 /* insert top 10 bits of address */ + lwz r8,0(r5) /* get pmd entry */ + rlwinm. r8,r8,0,0,19 /* extract address of pte page */ +#else + rlwinm r8,r4,13,19,29 /* Compute pgdir/pmd offset */ + lwzx r8,r8,r5 /* Get L1 entry */ + rlwinm. r8,r8,0,0,20 /* extract pt base address */ +#endif +#ifdef CONFIG_SMP + beq- .Lhash_page_out /* return if no mapping */ +#else + /* XXX it seems like the 601 will give a machine fault on the + rfi if its alignment is wrong (bottom 4 bits of address are + 8 or 0xc) and we have had a not-taken conditional branch + to the address following the rfi. */ + beqlr- +#endif +#ifndef CONFIG_PTE_64BIT + rlwimi r8,r4,22,20,29 /* insert next 10 bits of address */ +#else + rlwimi r8,r4,23,20,28 /* compute pte address */ + /* + * If PTE_64BIT is set, the low word is the flags word; use that + * word for locking since it contains all the interesting bits. + */ + addi r8,r8,PTE_FLAGS_OFFSET +#endif + + /* + * Update the linux PTE atomically. We do the lwarx up-front + * because almost always, there won't be a permission violation + * and there won't already be an HPTE, and thus we will have + * to update the PTE to set _PAGE_HASHPTE. -- paulus. + */ +.Lretry: + lwarx r6,0,r8 /* get linux-style pte, flag word */ +#ifdef CONFIG_PPC_KUAP + mfsrin r5,r4 + rlwinm r0,r9,28,_PAGE_RW /* MSR[PR] => _PAGE_RW */ + rlwinm r5,r5,12,_PAGE_RW /* Ks => _PAGE_RW */ + andc r5,r5,r0 /* Ks & ~MSR[PR] */ + andc r5,r6,r5 /* Clear _PAGE_RW when Ks = 1 && MSR[PR] = 0 */ + andc. r5,r3,r5 /* check access & ~permission */ +#else + andc. r5,r3,r6 /* check access & ~permission */ +#endif + rlwinm r0,r3,32-3,24,24 /* _PAGE_RW access -> _PAGE_DIRTY */ + ori r0,r0,_PAGE_ACCESSED|_PAGE_HASHPTE +#ifdef CONFIG_SMP + bne- .Lhash_page_out /* return if access not permitted */ +#else + bnelr- +#endif + or r5,r0,r6 /* set accessed/dirty bits */ +#ifdef CONFIG_PTE_64BIT +#ifdef CONFIG_SMP + subf r10,r6,r8 /* create false data dependency */ + subi r10,r10,PTE_FLAGS_OFFSET + lwzx r10,r6,r10 /* Get upper PTE word */ +#else + lwz r10,-PTE_FLAGS_OFFSET(r8) +#endif /* CONFIG_SMP */ +#endif /* CONFIG_PTE_64BIT */ + stwcx. r5,0,r8 /* attempt to update PTE */ + bne- .Lretry /* retry if someone got there first */ + + mfsrin r3,r4 /* get segment reg for segment */ + bl create_hpte /* add the hash table entry */ + +#ifdef CONFIG_SMP + eieio + lis r8, (mmu_hash_lock - PAGE_OFFSET)@ha + li r0,0 + stw r0, (mmu_hash_lock - PAGE_OFFSET)@l(r8) +#endif + b fast_hash_page_return + +#ifdef CONFIG_SMP +.Lhash_page_out: + eieio + lis r8, (mmu_hash_lock - PAGE_OFFSET)@ha + li r0,0 + stw r0, (mmu_hash_lock - PAGE_OFFSET)@l(r8) + blr +#endif /* CONFIG_SMP */ +_ASM_NOKPROBE_SYMBOL(hash_page) + +/* + * Add an entry for a particular page to the hash table. + * + * add_hash_page(unsigned context, unsigned long va, unsigned long pmdval) + * + * We assume any necessary modifications to the pte (e.g. setting + * the accessed bit) have already been done and that there is actually + * a hash table in use (i.e. we're not on a 603). + */ +_GLOBAL(add_hash_page) + mflr r0 + stw r0,4(r1) + +#ifdef CONFIG_SMP + lwz r8,TASK_CPU(r2) /* to go in mmu_hash_lock */ + oris r8,r8,12 +#endif /* CONFIG_SMP */ + + /* + * We disable interrupts here, even on UP, because we don't + * want to race with hash_page, and because we want the + * _PAGE_HASHPTE bit to be a reliable indication of whether + * the HPTE exists (or at least whether one did once). + * We also turn off the MMU for data accesses so that we + * we can't take a hash table miss (assuming the code is + * covered by a BAT). -- paulus + */ + mfmsr r9 + rlwinm r0,r9,0,17,15 /* clear bit 16 (MSR_EE) */ + rlwinm r0,r0,0,28,26 /* clear MSR_DR */ + mtmsr r0 + isync + +#ifdef CONFIG_SMP + lis r6, (mmu_hash_lock - PAGE_OFFSET)@ha + addi r6, r6, (mmu_hash_lock - PAGE_OFFSET)@l +10: lwarx r0,0,r6 /* take the mmu_hash_lock */ + cmpi 0,r0,0 + bne- 11f + stwcx. r8,0,r6 + beq+ 12f +11: lwz r0,0(r6) + cmpi 0,r0,0 + beq 10b + b 11b +12: isync +#endif + + /* + * Fetch the linux pte and test and set _PAGE_HASHPTE atomically. + * If _PAGE_HASHPTE was already set, we don't replace the existing + * HPTE, so we just unlock and return. + */ + mr r8,r5 +#ifndef CONFIG_PTE_64BIT + rlwimi r8,r4,22,20,29 +#else + rlwimi r8,r4,23,20,28 + addi r8,r8,PTE_FLAGS_OFFSET +#endif +1: lwarx r6,0,r8 + andi. r0,r6,_PAGE_HASHPTE + bne 9f /* if HASHPTE already set, done */ +#ifdef CONFIG_PTE_64BIT +#ifdef CONFIG_SMP + subf r10,r6,r8 /* create false data dependency */ + subi r10,r10,PTE_FLAGS_OFFSET + lwzx r10,r6,r10 /* Get upper PTE word */ +#else + lwz r10,-PTE_FLAGS_OFFSET(r8) +#endif /* CONFIG_SMP */ +#endif /* CONFIG_PTE_64BIT */ + ori r5,r6,_PAGE_HASHPTE + stwcx. r5,0,r8 + bne- 1b + + /* Convert context and va to VSID */ + mulli r3,r3,897*16 /* multiply context by context skew */ + rlwinm r0,r4,4,28,31 /* get ESID (top 4 bits of va) */ + mulli r0,r0,0x111 /* multiply by ESID skew */ + add r3,r3,r0 /* note create_hpte trims to 24 bits */ + + bl create_hpte + +9: +#ifdef CONFIG_SMP + lis r6, (mmu_hash_lock - PAGE_OFFSET)@ha + addi r6, r6, (mmu_hash_lock - PAGE_OFFSET)@l + eieio + li r0,0 + stw r0,0(r6) /* clear mmu_hash_lock */ +#endif + + /* reenable interrupts and DR */ + mtmsr r9 + isync + + lwz r0,4(r1) + mtlr r0 + blr +_ASM_NOKPROBE_SYMBOL(add_hash_page) + +/* + * This routine adds a hardware PTE to the hash table. + * It is designed to be called with the MMU either on or off. + * r3 contains the VSID, r4 contains the virtual address, + * r5 contains the linux PTE, r6 contains the old value of the + * linux PTE (before setting _PAGE_HASHPTE). r10 contains the + * upper half of the PTE if CONFIG_PTE_64BIT. + * On SMP, the caller should have the mmu_hash_lock held. + * We assume that the caller has (or will) set the _PAGE_HASHPTE + * bit in the linux PTE in memory. The value passed in r6 should + * be the old linux PTE value; if it doesn't have _PAGE_HASHPTE set + * this routine will skip the search for an existing HPTE. + * This procedure modifies r0, r3 - r6, r8, cr0. + * -- paulus. + * + * For speed, 4 of the instructions get patched once the size and + * physical address of the hash table are known. These definitions + * of Hash_base and Hash_bits below are for the early hash table. + */ +Hash_base = early_hash +Hash_bits = 12 /* e.g. 256kB hash table */ +Hash_msk = (((1 << Hash_bits) - 1) * 64) + +/* defines for the PTE format for 32-bit PPCs */ +#define HPTE_SIZE 8 +#define PTEG_SIZE 64 +#define LG_PTEG_SIZE 6 +#define LDPTEu lwzu +#define LDPTE lwz +#define STPTE stw +#define CMPPTE cmpw +#define PTE_H 0x40 +#define PTE_V 0x80000000 +#define TST_V(r) rlwinm. r,r,0,0,0 +#define SET_V(r) oris r,r,PTE_V@h +#define CLR_V(r,t) rlwinm r,r,0,1,31 + +#define HASH_LEFT 31-(LG_PTEG_SIZE+Hash_bits-1) +#define HASH_RIGHT 31-LG_PTEG_SIZE + +__REF +_GLOBAL(create_hpte) + /* Convert linux-style PTE (r5) to low word of PPC-style PTE (r8) */ + rlwinm r8,r5,32-9,30,30 /* _PAGE_RW -> PP msb */ + rlwinm r0,r5,32-6,30,30 /* _PAGE_DIRTY -> PP msb */ + and r8,r8,r0 /* writable if _RW & _DIRTY */ + rlwimi r5,r5,32-1,30,30 /* _PAGE_USER -> PP msb */ + rlwimi r5,r5,32-2,31,31 /* _PAGE_USER -> PP lsb */ + ori r8,r8,0xe04 /* clear out reserved bits */ + andc r8,r5,r8 /* PP = user? (rw&dirty? 1: 3): 0 */ +BEGIN_FTR_SECTION + rlwinm r8,r8,0,~_PAGE_COHERENT /* clear M (coherence not required) */ +END_FTR_SECTION_IFCLR(CPU_FTR_NEED_COHERENT) +#ifdef CONFIG_PTE_64BIT + /* Put the XPN bits into the PTE */ + rlwimi r8,r10,8,20,22 + rlwimi r8,r10,2,29,29 +#endif + + /* Construct the high word of the PPC-style PTE (r5) */ + rlwinm r5,r3,7,1,24 /* put VSID in 0x7fffff80 bits */ + rlwimi r5,r4,10,26,31 /* put in API (abbrev page index) */ + SET_V(r5) /* set V (valid) bit */ + + patch_site 0f, patch__hash_page_A0 + patch_site 1f, patch__hash_page_A1 + patch_site 2f, patch__hash_page_A2 + /* Get the address of the primary PTE group in the hash table (r3) */ +0: lis r0, (Hash_base - PAGE_OFFSET)@h /* base address of hash table */ +1: rlwimi r0,r3,LG_PTEG_SIZE,HASH_LEFT,HASH_RIGHT /* VSID -> hash */ +2: rlwinm r3,r4,20+LG_PTEG_SIZE,HASH_LEFT,HASH_RIGHT /* PI -> hash */ + xor r3,r3,r0 /* make primary hash */ + li r0,8 /* PTEs/group */ + + /* + * Test the _PAGE_HASHPTE bit in the old linux PTE, and skip the search + * if it is clear, meaning that the HPTE isn't there already... + */ + andi. r6,r6,_PAGE_HASHPTE + beq+ 10f /* no PTE: go look for an empty slot */ + tlbie r4 + + /* Search the primary PTEG for a PTE whose 1st (d)word matches r5 */ + mtctr r0 + addi r4,r3,-HPTE_SIZE +1: LDPTEu r6,HPTE_SIZE(r4) /* get next PTE */ + CMPPTE 0,r6,r5 + bdnzf 2,1b /* loop while ctr != 0 && !cr0.eq */ + beq+ .Lfound_slot + + patch_site 0f, patch__hash_page_B + /* Search the secondary PTEG for a matching PTE */ + ori r5,r5,PTE_H /* set H (secondary hash) bit */ +0: xoris r4,r3,Hash_msk>>16 /* compute secondary hash */ + xori r4,r4,(-PTEG_SIZE & 0xffff) + addi r4,r4,-HPTE_SIZE + mtctr r0 +2: LDPTEu r6,HPTE_SIZE(r4) + CMPPTE 0,r6,r5 + bdnzf 2,2b + beq+ .Lfound_slot + xori r5,r5,PTE_H /* clear H bit again */ + + /* Search the primary PTEG for an empty slot */ +10: mtctr r0 + addi r4,r3,-HPTE_SIZE /* search primary PTEG */ +1: LDPTEu r6,HPTE_SIZE(r4) /* get next PTE */ + TST_V(r6) /* test valid bit */ + bdnzf 2,1b /* loop while ctr != 0 && !cr0.eq */ + beq+ .Lfound_empty + + patch_site 0f, patch__hash_page_C + /* Search the secondary PTEG for an empty slot */ + ori r5,r5,PTE_H /* set H (secondary hash) bit */ +0: xoris r4,r3,Hash_msk>>16 /* compute secondary hash */ + xori r4,r4,(-PTEG_SIZE & 0xffff) + addi r4,r4,-HPTE_SIZE + mtctr r0 +2: LDPTEu r6,HPTE_SIZE(r4) + TST_V(r6) + bdnzf 2,2b + beq+ .Lfound_empty + xori r5,r5,PTE_H /* clear H bit again */ + + /* + * Choose an arbitrary slot in the primary PTEG to overwrite. + * Since both the primary and secondary PTEGs are full, and we + * have no information that the PTEs in the primary PTEG are + * more important or useful than those in the secondary PTEG, + * and we know there is a definite (although small) speed + * advantage to putting the PTE in the primary PTEG, we always + * put the PTE in the primary PTEG. + */ + + lis r4, (next_slot - PAGE_OFFSET)@ha /* get next evict slot */ + lwz r6, (next_slot - PAGE_OFFSET)@l(r4) + addi r6,r6,HPTE_SIZE /* search for candidate */ + andi. r6,r6,7*HPTE_SIZE + stw r6,next_slot@l(r4) + add r4,r3,r6 + +#ifndef CONFIG_SMP + /* Store PTE in PTEG */ +.Lfound_empty: + STPTE r5,0(r4) +.Lfound_slot: + STPTE r8,HPTE_SIZE/2(r4) + +#else /* CONFIG_SMP */ +/* + * Between the tlbie above and updating the hash table entry below, + * another CPU could read the hash table entry and put it in its TLB. + * There are 3 cases: + * 1. using an empty slot + * 2. updating an earlier entry to change permissions (i.e. enable write) + * 3. taking over the PTE for an unrelated address + * + * In each case it doesn't really matter if the other CPUs have the old + * PTE in their TLB. So we don't need to bother with another tlbie here, + * which is convenient as we've overwritten the register that had the + * address. :-) The tlbie above is mainly to make sure that this CPU comes + * and gets the new PTE from the hash table. + * + * We do however have to make sure that the PTE is never in an invalid + * state with the V bit set. + */ +.Lfound_empty: +.Lfound_slot: + CLR_V(r5,r0) /* clear V (valid) bit in PTE */ + STPTE r5,0(r4) + sync + TLBSYNC + STPTE r8,HPTE_SIZE/2(r4) /* put in correct RPN, WIMG, PP bits */ + sync + SET_V(r5) + STPTE r5,0(r4) /* finally set V bit in PTE */ +#endif /* CONFIG_SMP */ + + sync /* make sure pte updates get to memory */ + blr + .previous +_ASM_NOKPROBE_SYMBOL(create_hpte) + + .section .bss + .align 2 +next_slot: + .space 4 + .previous + +/* + * Flush the entry for a particular page from the hash table. + * + * flush_hash_pages(unsigned context, unsigned long va, unsigned long pmdval, + * int count) + * + * We assume that there is a hash table in use (Hash != 0). + */ +__REF +_GLOBAL(flush_hash_pages) + /* + * We disable interrupts here, even on UP, because we want + * the _PAGE_HASHPTE bit to be a reliable indication of + * whether the HPTE exists (or at least whether one did once). + * We also turn off the MMU for data accesses so that we + * we can't take a hash table miss (assuming the code is + * covered by a BAT). -- paulus + */ + mfmsr r10 + rlwinm r0,r10,0,17,15 /* clear bit 16 (MSR_EE) */ + rlwinm r0,r0,0,28,26 /* clear MSR_DR */ + mtmsr r0 + isync + + /* First find a PTE in the range that has _PAGE_HASHPTE set */ +#ifndef CONFIG_PTE_64BIT + rlwimi r5,r4,22,20,29 +#else + rlwimi r5,r4,23,20,28 + addi r5,r5,PTE_FLAGS_OFFSET +#endif +1: lwz r0,0(r5) + cmpwi cr1,r6,1 + andi. r0,r0,_PAGE_HASHPTE + bne 2f + ble cr1,19f + addi r4,r4,0x1000 + addi r5,r5,PTE_T_SIZE + addi r6,r6,-1 + b 1b + + /* Convert context and va to VSID */ +2: mulli r3,r3,897*16 /* multiply context by context skew */ + rlwinm r0,r4,4,28,31 /* get ESID (top 4 bits of va) */ + mulli r0,r0,0x111 /* multiply by ESID skew */ + add r3,r3,r0 /* note code below trims to 24 bits */ + + /* Construct the high word of the PPC-style PTE (r11) */ + rlwinm r11,r3,7,1,24 /* put VSID in 0x7fffff80 bits */ + rlwimi r11,r4,10,26,31 /* put in API (abbrev page index) */ + SET_V(r11) /* set V (valid) bit */ + +#ifdef CONFIG_SMP + lis r9, (mmu_hash_lock - PAGE_OFFSET)@ha + addi r9, r9, (mmu_hash_lock - PAGE_OFFSET)@l + tophys (r8, r2) + lwz r8, TASK_CPU(r8) + oris r8,r8,9 +10: lwarx r0,0,r9 + cmpi 0,r0,0 + bne- 11f + stwcx. r8,0,r9 + beq+ 12f +11: lwz r0,0(r9) + cmpi 0,r0,0 + beq 10b + b 11b +12: isync +#endif + + /* + * Check the _PAGE_HASHPTE bit in the linux PTE. If it is + * already clear, we're done (for this pte). If not, + * clear it (atomically) and proceed. -- paulus. + */ +33: lwarx r8,0,r5 /* fetch the pte flags word */ + andi. r0,r8,_PAGE_HASHPTE + beq 8f /* done if HASHPTE is already clear */ + rlwinm r8,r8,0,31,29 /* clear HASHPTE bit */ + stwcx. r8,0,r5 /* update the pte */ + bne- 33b + + patch_site 0f, patch__flush_hash_A0 + patch_site 1f, patch__flush_hash_A1 + patch_site 2f, patch__flush_hash_A2 + /* Get the address of the primary PTE group in the hash table (r3) */ +0: lis r8, (Hash_base - PAGE_OFFSET)@h /* base address of hash table */ +1: rlwimi r8,r3,LG_PTEG_SIZE,HASH_LEFT,HASH_RIGHT /* VSID -> hash */ +2: rlwinm r0,r4,20+LG_PTEG_SIZE,HASH_LEFT,HASH_RIGHT /* PI -> hash */ + xor r8,r0,r8 /* make primary hash */ + + /* Search the primary PTEG for a PTE whose 1st (d)word matches r5 */ + li r0,8 /* PTEs/group */ + mtctr r0 + addi r12,r8,-HPTE_SIZE +1: LDPTEu r0,HPTE_SIZE(r12) /* get next PTE */ + CMPPTE 0,r0,r11 + bdnzf 2,1b /* loop while ctr != 0 && !cr0.eq */ + beq+ 3f + + patch_site 0f, patch__flush_hash_B + /* Search the secondary PTEG for a matching PTE */ + ori r11,r11,PTE_H /* set H (secondary hash) bit */ + li r0,8 /* PTEs/group */ +0: xoris r12,r8,Hash_msk>>16 /* compute secondary hash */ + xori r12,r12,(-PTEG_SIZE & 0xffff) + addi r12,r12,-HPTE_SIZE + mtctr r0 +2: LDPTEu r0,HPTE_SIZE(r12) + CMPPTE 0,r0,r11 + bdnzf 2,2b + xori r11,r11,PTE_H /* clear H again */ + bne- 4f /* should rarely fail to find it */ + +3: li r0,0 + STPTE r0,0(r12) /* invalidate entry */ +4: sync + tlbie r4 /* in hw tlb too */ + sync + +8: ble cr1,9f /* if all ptes checked */ +81: addi r6,r6,-1 + addi r5,r5,PTE_T_SIZE + addi r4,r4,0x1000 + lwz r0,0(r5) /* check next pte */ + cmpwi cr1,r6,1 + andi. r0,r0,_PAGE_HASHPTE + bne 33b + bgt cr1,81b + +9: +#ifdef CONFIG_SMP + TLBSYNC + li r0,0 + stw r0,0(r9) /* clear mmu_hash_lock */ +#endif + +19: mtmsr r10 + isync + blr + .previous +EXPORT_SYMBOL(flush_hash_pages) +_ASM_NOKPROBE_SYMBOL(flush_hash_pages) |