From patchwork Thu Nov 21 16:21:33 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mike Rapoport X-Patchwork-Id: 11256525 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 036F713A4 for ; Thu, 21 Nov 2019 16:21:53 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id A9FD3206B6 for ; Thu, 21 Nov 2019 16:21:52 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="uuqmbfiu" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A9FD3206B6 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 0987B6B0356; Thu, 21 Nov 2019 11:21:51 -0500 (EST) Delivered-To: linux-mm-outgoing@kvack.org Received: by kanga.kvack.org (Postfix, from userid 40) id F3CF06B0357; Thu, 21 Nov 2019 11:21:50 -0500 (EST) X-Original-To: int-list-linux-mm@kvack.org X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id E2FE36B0358; Thu, 21 Nov 2019 11:21:50 -0500 (EST) X-Original-To: linux-mm@kvack.org X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0051.hostedemail.com [216.40.44.51]) by kanga.kvack.org (Postfix) with ESMTP id BCF8A6B0356 for ; Thu, 21 Nov 2019 11:21:50 -0500 (EST) Received: from smtpin02.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with SMTP id 745112C06 for ; Thu, 21 Nov 2019 16:21:50 +0000 (UTC) X-FDA: 76180800780.02.spy84_2d14b08127763 X-Spam-Summary: 2,0,0,7515142d50f87813,d41d8cd98f00b204,rppt@kernel.org,:ralf@linux-mips.org:paulburton@kernel.org:jhogan@kernel.org:linux-mips@vger.kernel.org:linux-kernel@vger.kernel.org::rppt@kernel.org:rppt@linux.ibm.com,RULES_HIT:4:41:69:355:379:541:800:960:966:973:988:989:1260:1311:1314:1345:1359:1431:1437:1515:1605:1730:1747:1777:1792:1981:2194:2196:2198:2199:2200:2201:2393:2559:2562:2640:2898:3138:3139:3140:3141:3142:3865:3866:3867:3868:4321:4385:4605:5007:6117:6119:6261:6653:7576:7903:7904:9036:10004:11026:11473:11657:11658:11914:12043:12296:12297:12438:12517:12519:12555:12663:12679:12683:12895:12986:13894:14096:14394:21080:21433:21451:21627:30003:30029:30054:30070,0,RBL:198.145.29.99:@kernel.org:.lbl8.mailshell.net-62.2.0.100 64.100.201.201,CacheIP:none,Bayesian:0.5,0.5,0.5,Netcheck:none,DomainCache:0,MSF:not bulk,SPF:fp,MSBL:0,DNSBL:neutral,Custom_rules:0:0:0,LFtime:4,LUA_SUMMARY:none X-HE-Tag: spy84_2d14b08127763 X-Filterd-Recvd-Size: 16210 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf42.hostedemail.com (Postfix) with ESMTP for ; Thu, 21 Nov 2019 16:21:49 +0000 (UTC) Received: from aquarius.haifa.ibm.com (nesher1.haifa.il.ibm.com [195.110.40.7]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 58796206D7; Thu, 21 Nov 2019 16:21:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1574353308; bh=UeXsvyhoe7zQzbY/U3+mvsOn/wzS9Z9CaXshYcTeu3w=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=uuqmbfiu9dO4JF8weSh043j2a53GuSi1w9or5lNY7qxpNEcQ/CAOrcFNzrNfcnf3l SElr4FQUGph+gU+Ku9u3/pyPdDKXCpYr4WkESCe4GFmUEef4Whnl9oqYWrWMTLO3RH Zz0Ibsv5pwhBnaJyKimRP9btn1WVZfBzjk5VbxTQ= From: Mike Rapoport To: Ralf Baechle , Paul Burton , James Hogan Cc: linux-mips@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Mike Rapoport , Mike Rapoport Subject: [PATCH 3/3] mips: add support for folded p4d page tables Date: Thu, 21 Nov 2019 18:21:33 +0200 Message-Id: <20191121162133.15833-4-rppt@kernel.org> X-Mailer: git-send-email 2.24.0 In-Reply-To: <20191121162133.15833-1-rppt@kernel.org> References: <20191121162133.15833-1-rppt@kernel.org> MIME-Version: 1.0 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: From: Mike Rapoport Implement primitives necessary for the 4th level folding, add walks of p4d level where appropriate, replace 5leve-fixup.h with pgtable-nop4d.h and drop usage of __ARCH_USE_5LEVEL_HACK. Signed-off-by: Mike Rapoport --- arch/mips/include/asm/fixmap.h | 2 +- arch/mips/include/asm/pgalloc.h | 4 ++-- arch/mips/include/asm/pgtable-32.h | 1 - arch/mips/include/asm/pgtable-64.h | 37 +++++++++++++++--------------- arch/mips/kvm/mmu.c | 16 +++++++++---- arch/mips/kvm/trap_emul.c | 4 +++- arch/mips/mm/c-r3k.c | 4 +++- arch/mips/mm/c-r4k.c | 4 +++- arch/mips/mm/c-tx39.c | 4 +++- arch/mips/mm/fault.c | 10 ++++++-- arch/mips/mm/hugetlbpage.c | 14 +++++++---- arch/mips/mm/ioremap.c | 6 ++++- arch/mips/mm/pgtable-32.c | 4 +++- arch/mips/mm/tlb-r4k.c | 4 +++- 14 files changed, 75 insertions(+), 39 deletions(-) diff --git a/arch/mips/include/asm/fixmap.h b/arch/mips/include/asm/fixmap.h index 6842ffafd1e7..1784d4348c36 100644 --- a/arch/mips/include/asm/fixmap.h +++ b/arch/mips/include/asm/fixmap.h @@ -70,7 +70,7 @@ enum fixed_addresses { #include #define kmap_get_fixmap_pte(vaddr) \ - pte_offset_kernel(pmd_offset(pud_offset(pgd_offset_k(vaddr), (vaddr)), (vaddr)), (vaddr)) + pte_offset_kernel(pmd_offset(pud_offset(p4d_offset(pgd_offset_k(vaddr), (vaddr)), (vaddr)), (vaddr)), (vaddr)) /* * Called from pgtable_init() diff --git a/arch/mips/include/asm/pgalloc.h b/arch/mips/include/asm/pgalloc.h index 166842337eb2..fa77cb71f303 100644 --- a/arch/mips/include/asm/pgalloc.h +++ b/arch/mips/include/asm/pgalloc.h @@ -96,9 +96,9 @@ static inline void pud_free(struct mm_struct *mm, pud_t *pud) free_pages((unsigned long)pud, PUD_ORDER); } -static inline void pgd_populate(struct mm_struct *mm, pgd_t *pgd, pud_t *pud) +static inline void p4d_populate(struct mm_struct *mm, p4d_t *p4d, pud_t *pud) { - set_pgd(pgd, __pgd((unsigned long)pud)); + set_p4d(p4d, __p4d((unsigned long)pud)); } #define __pud_free_tlb(tlb, x, addr) pud_free((tlb)->mm, x) diff --git a/arch/mips/include/asm/pgtable-32.h b/arch/mips/include/asm/pgtable-32.h index 6089c5c4936c..1945c8970141 100644 --- a/arch/mips/include/asm/pgtable-32.h +++ b/arch/mips/include/asm/pgtable-32.h @@ -16,7 +16,6 @@ #include #include -#define __ARCH_USE_5LEVEL_HACK #include #ifdef CONFIG_HIGHMEM diff --git a/arch/mips/include/asm/pgtable-64.h b/arch/mips/include/asm/pgtable-64.h index 62a9e2c31312..f92716cfa4f4 100644 --- a/arch/mips/include/asm/pgtable-64.h +++ b/arch/mips/include/asm/pgtable-64.h @@ -17,13 +17,12 @@ #include #include -#define __ARCH_USE_5LEVEL_HACK #if CONFIG_PGTABLE_LEVELS == 2 #include #elif CONFIG_PGTABLE_LEVELS == 3 #include #else -#include +#include #endif /* @@ -188,47 +187,49 @@ extern pud_t invalid_pud_table[PTRS_PER_PUD]; /* * Empty pgd entries point to the invalid_pud_table. */ -static inline int pgd_none(pgd_t pgd) +static inline int p4d_none(p4d_t p4d) { - return pgd_val(pgd) == (unsigned long)invalid_pud_table; + return p4d_val(p4d) == (unsigned long)invalid_pud_table; } -static inline int pgd_bad(pgd_t pgd) +static inline int p4d_bad(p4d_t p4d) { - if (unlikely(pgd_val(pgd) & ~PAGE_MASK)) + if (unlikely(p4d_val(p4d) & ~PAGE_MASK)) return 1; return 0; } -static inline int pgd_present(pgd_t pgd) +static inline int p4d_present(p4d_t p4d) { - return pgd_val(pgd) != (unsigned long)invalid_pud_table; + return p4d_val(p4d) != (unsigned long)invalid_pud_table; } -static inline void pgd_clear(pgd_t *pgdp) +static inline void p4d_clear(p4d_t *p4dp) { - pgd_val(*pgdp) = (unsigned long)invalid_pud_table; + p4d_val(*p4dp) = (unsigned long)invalid_pud_table; } #define pud_index(address) (((address) >> PUD_SHIFT) & (PTRS_PER_PUD - 1)) -static inline unsigned long pgd_page_vaddr(pgd_t pgd) +static inline unsigned long p4d_page_vaddr(p4d_t p4d) { - return pgd_val(pgd); + return p4d_val(p4d); } -#define pgd_phys(pgd) virt_to_phys((void *)pgd_val(pgd)) -#define pgd_page(pgd) (pfn_to_page(pgd_phys(pgd) >> PAGE_SHIFT)) +#define p4d_phys(p4d) virt_to_phys((void *)p4d_val(p4d)) +#define p4d_page(p4d) (pfn_to_page(p4d_phys(p4d) >> PAGE_SHIFT)) -static inline pud_t *pud_offset(pgd_t *pgd, unsigned long address) +#define p4d_index(address) (((address) >> P4D_SHIFT) & (PTRS_PER_P4D - 1)) + +static inline pud_t *pud_offset(p4d_t *p4d, unsigned long address) { - return (pud_t *)pgd_page_vaddr(*pgd) + pud_index(address); + return (pud_t *)p4d_page_vaddr(*p4d) + pud_index(address); } -static inline void set_pgd(pgd_t *pgd, pgd_t pgdval) +static inline void set_p4d(p4d_t *p4d, p4d_t p4dval) { - *pgd = pgdval; + *p4d = p4dval; } #endif diff --git a/arch/mips/kvm/mmu.c b/arch/mips/kvm/mmu.c index a62a434b256e..7dad7a293eae 100644 --- a/arch/mips/kvm/mmu.c +++ b/arch/mips/kvm/mmu.c @@ -136,6 +136,7 @@ pgd_t *kvm_pgd_alloc(void) static pte_t *kvm_mips_walk_pgd(pgd_t *pgd, struct kvm_mmu_memory_cache *cache, unsigned long addr) { + p4d_t *p4d; pud_t *pud; pmd_t *pmd; @@ -145,7 +146,8 @@ static pte_t *kvm_mips_walk_pgd(pgd_t *pgd, struct kvm_mmu_memory_cache *cache, BUG(); return NULL; } - pud = pud_offset(pgd, addr); + p4d = p4d_offset(pgd, addr); + pud = pud_offset(p4d, addr); if (pud_none(*pud)) { pmd_t *new_pmd; @@ -258,6 +260,7 @@ static bool kvm_mips_flush_gpa_pud(pud_t *pud, unsigned long start_gpa, static bool kvm_mips_flush_gpa_pgd(pgd_t *pgd, unsigned long start_gpa, unsigned long end_gpa) { + p4d_t *p4d; pud_t *pud; unsigned long end = ~0ul; int i_min = pgd_index(start_gpa); @@ -269,7 +272,8 @@ static bool kvm_mips_flush_gpa_pgd(pgd_t *pgd, unsigned long start_gpa, if (!pgd_present(pgd[i])) continue; - pud = pud_offset(pgd + i, 0); + p4d = p4d_offset(pgd, 0); + pud = pud_offset(p4d + i, 0); if (i == i_max) end = end_gpa; @@ -378,6 +382,7 @@ static int kvm_mips_##name##_pgd(pgd_t *pgd, unsigned long start, \ unsigned long end) \ { \ int ret = 0; \ + p4d_t *p4d; \ pud_t *pud; \ unsigned long cur_end = ~0ul; \ int i_min = pgd_index(start); \ @@ -388,7 +393,8 @@ static int kvm_mips_##name##_pgd(pgd_t *pgd, unsigned long start, \ if (!pgd_present(pgd[i])) \ continue; \ \ - pud = pud_offset(pgd + i, 0); \ + p4d = p4d_offset(pgd, 0); \ + pud = pud_offset(p4d + i, 0); \ if (i == i_max) \ cur_end = end; \ \ @@ -916,6 +922,7 @@ static bool kvm_mips_flush_gva_pud(pud_t *pud, unsigned long start_gva, static bool kvm_mips_flush_gva_pgd(pgd_t *pgd, unsigned long start_gva, unsigned long end_gva) { + p4d_t *p4d; pud_t *pud; unsigned long end = ~0ul; int i_min = pgd_index(start_gva); @@ -927,7 +934,8 @@ static bool kvm_mips_flush_gva_pgd(pgd_t *pgd, unsigned long start_gva, if (!pgd_present(pgd[i])) continue; - pud = pud_offset(pgd + i, 0); + p4d = p4d_offset(pgd, 0); + pud = pud_offset(p4d + i, 0); if (i == i_max) end = end_gva; diff --git a/arch/mips/kvm/trap_emul.c b/arch/mips/kvm/trap_emul.c index 73daa6ad33af..5a11e83dffe6 100644 --- a/arch/mips/kvm/trap_emul.c +++ b/arch/mips/kvm/trap_emul.c @@ -564,6 +564,7 @@ static void kvm_mips_emul_free_gva_pt(pgd_t *pgd) /* Don't free host kernel page tables copied from init_mm.pgd */ const unsigned long end = 0x80000000; unsigned long pgd_va, pud_va, pmd_va; + p4d_t *p4d; pud_t *pud; pmd_t *pmd; pte_t *pte; @@ -576,7 +577,8 @@ static void kvm_mips_emul_free_gva_pt(pgd_t *pgd) pgd_va = (unsigned long)i << PGDIR_SHIFT; if (pgd_va >= end) break; - pud = pud_offset(pgd + i, 0); + p4d = p4d_offset(pgd, 0); + pud = pud_offset(p4d + i, 0); for (j = 0; j < PTRS_PER_PUD; j++) { if (pud_none(pud[j])) continue; diff --git a/arch/mips/mm/c-r3k.c b/arch/mips/mm/c-r3k.c index 0ca401ddf3b7..15bb8cf59828 100644 --- a/arch/mips/mm/c-r3k.c +++ b/arch/mips/mm/c-r3k.c @@ -241,6 +241,7 @@ static void r3k_flush_cache_page(struct vm_area_struct *vma, int exec = vma->vm_flags & VM_EXEC; struct mm_struct *mm = vma->vm_mm; pgd_t *pgdp; + p4d_t *p4dp; pud_t *pudp; pmd_t *pmdp; pte_t *ptep; @@ -253,7 +254,8 @@ static void r3k_flush_cache_page(struct vm_area_struct *vma, return; pgdp = pgd_offset(mm, addr); - pudp = pud_offset(pgdp, addr); + p4dp = p4d_offset(pgdp, addr); + pudp = pud_offset(p4dp, addr); pmdp = pmd_offset(pudp, addr); ptep = pte_offset(pmdp, addr); diff --git a/arch/mips/mm/c-r4k.c b/arch/mips/mm/c-r4k.c index 89b9c851d822..cc76ebad4482 100644 --- a/arch/mips/mm/c-r4k.c +++ b/arch/mips/mm/c-r4k.c @@ -650,6 +650,7 @@ static inline void local_r4k_flush_cache_page(void *args) struct mm_struct *mm = vma->vm_mm; int map_coherent = 0; pgd_t *pgdp; + p4d_t *p4dp; pud_t *pudp; pmd_t *pmdp; pte_t *ptep; @@ -664,7 +665,8 @@ static inline void local_r4k_flush_cache_page(void *args) addr &= PAGE_MASK; pgdp = pgd_offset(mm, addr); - pudp = pud_offset(pgdp, addr); + p4dp = p4d_offset(pgdp, addr); + pudp = pud_offset(p4dp, addr); pmdp = pmd_offset(pudp, addr); ptep = pte_offset(pmdp, addr); diff --git a/arch/mips/mm/c-tx39.c b/arch/mips/mm/c-tx39.c index b7c8a9d79c35..686867270627 100644 --- a/arch/mips/mm/c-tx39.c +++ b/arch/mips/mm/c-tx39.c @@ -170,6 +170,7 @@ static void tx39_flush_cache_page(struct vm_area_struct *vma, unsigned long page int exec = vma->vm_flags & VM_EXEC; struct mm_struct *mm = vma->vm_mm; pgd_t *pgdp; + p4d_t *p4dp; pud_t *pudp; pmd_t *pmdp; pte_t *ptep; @@ -183,7 +184,8 @@ static void tx39_flush_cache_page(struct vm_area_struct *vma, unsigned long page page &= PAGE_MASK; pgdp = pgd_offset(mm, page); - pudp = pud_offset(pgdp, page); + p4dp = p4d_offset(pgdp, page); + pudp = pud_offset(p4dp, page); pmdp = pmd_offset(pudp, page); ptep = pte_offset(pmdp, page); diff --git a/arch/mips/mm/fault.c b/arch/mips/mm/fault.c index 524af96c8131..1e8d00793784 100644 --- a/arch/mips/mm/fault.c +++ b/arch/mips/mm/fault.c @@ -294,6 +294,7 @@ static void __kprobes __do_page_fault(struct pt_regs *regs, unsigned long write, */ int offset = pgd_index(address); pgd_t *pgd, *pgd_k; + p4d_t *p4d, *p4d_k; pud_t *pud, *pud_k; pmd_t *pmd, *pmd_k; pte_t *pte_k; @@ -305,8 +306,13 @@ static void __kprobes __do_page_fault(struct pt_regs *regs, unsigned long write, goto no_context; set_pgd(pgd, *pgd_k); - pud = pud_offset(pgd, address); - pud_k = pud_offset(pgd_k, address); + p4d = p4d_offset(pgd, address); + p4d_k = p4d_offset(pgd_k, address); + if (!p4d_present(*p4d_k)) + goto no_context; + + pud = pud_offset(p4d, address); + pud_k = pud_offset(p4d_k, address); if (!pud_present(*pud_k)) goto no_context; diff --git a/arch/mips/mm/hugetlbpage.c b/arch/mips/mm/hugetlbpage.c index cef152234312..77ffece9c270 100644 --- a/arch/mips/mm/hugetlbpage.c +++ b/arch/mips/mm/hugetlbpage.c @@ -25,11 +25,13 @@ pte_t *huge_pte_alloc(struct mm_struct *mm, unsigned long addr, unsigned long sz) { pgd_t *pgd; + p4d_t *p4d; pud_t *pud; pte_t *pte = NULL; pgd = pgd_offset(mm, addr); - pud = pud_alloc(mm, pgd, addr); + p4d = p4d_alloc(mm, pgd, addr); + pud = pud_alloc(mm, p4d, addr); if (pud) pte = (pte_t *)pmd_alloc(mm, pud, addr); @@ -40,14 +42,18 @@ pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr, unsigned long sz) { pgd_t *pgd; + p4d_t *p4d; pud_t *pud; pmd_t *pmd = NULL; pgd = pgd_offset(mm, addr); if (pgd_present(*pgd)) { - pud = pud_offset(pgd, addr); - if (pud_present(*pud)) - pmd = pmd_offset(pud, addr); + p4d = p4d_offset(pgd, addr); + if (p4d_present(*p4d)) { + pud = pud_offset(p4d, addr); + if (pud_present(*pud)) + pmd = pmd_offset(pud, addr); + } } return (pte_t *) pmd; } diff --git a/arch/mips/mm/ioremap.c b/arch/mips/mm/ioremap.c index 1601d90b087b..8317f337a86e 100644 --- a/arch/mips/mm/ioremap.c +++ b/arch/mips/mm/ioremap.c @@ -78,11 +78,15 @@ static int remap_area_pages(unsigned long address, phys_addr_t phys_addr, flush_cache_all(); BUG_ON(address >= end); do { + p4d_t *p4d; pud_t *pud; pmd_t *pmd; error = -ENOMEM; - pud = pud_alloc(&init_mm, dir, address); + p4d = p4d_alloc(&init_mm, dir, address); + if (!p4d) + break; + pud = pud_alloc(&init_mm, p4d, address); if (!pud) break; pmd = pmd_alloc(&init_mm, pud, address); diff --git a/arch/mips/mm/pgtable-32.c b/arch/mips/mm/pgtable-32.c index 621a01fbef64..37c7a01427d2 100644 --- a/arch/mips/mm/pgtable-32.c +++ b/arch/mips/mm/pgtable-32.c @@ -56,6 +56,7 @@ void __init pagetable_init(void) pgd_t *pgd_base; #ifdef CONFIG_HIGHMEM pgd_t *pgd; + p4d_t *p4d; pud_t *pud; pmd_t *pmd; pte_t *pte; @@ -82,7 +83,8 @@ void __init pagetable_init(void) fixrange_init(vaddr & PMD_MASK, vaddr + PAGE_SIZE*LAST_PKMAP, pgd_base); pgd = swapper_pg_dir + pgd_index(vaddr); - pud = pud_offset(pgd, vaddr); + p4d = p4d_offset(pgd, vaddr); + pud = pud_offset(p4d, vaddr); pmd = pmd_offset(pud, vaddr); pte = pte_offset_kernel(pmd, vaddr); pkmap_page_table = pte; diff --git a/arch/mips/mm/tlb-r4k.c b/arch/mips/mm/tlb-r4k.c index c13e46ced425..c300fb4c152b 100644 --- a/arch/mips/mm/tlb-r4k.c +++ b/arch/mips/mm/tlb-r4k.c @@ -295,6 +295,7 @@ void __update_tlb(struct vm_area_struct * vma, unsigned long address, pte_t pte) { unsigned long flags; pgd_t *pgdp; + p4d_t *p4dp; pud_t *pudp; pmd_t *pmdp; pte_t *ptep; @@ -320,7 +321,8 @@ void __update_tlb(struct vm_area_struct * vma, unsigned long address, pte_t pte) mtc0_tlbw_hazard(); tlb_probe(); tlb_probe_hazard(); - pudp = pud_offset(pgdp, address); + p4dp = p4d_offset(pgdp, address); + pudp = pud_offset(p4dp, address); pmdp = pmd_offset(pudp, address); idx = read_c0_index(); #ifdef CONFIG_MIPS_HUGE_TLB_SUPPORT