e500_hugetlbpage.c

  1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 * PPC Huge TLB Page Support for Book3E MMU
  4 *
  5 * Copyright (C) 2009 David Gibson, IBM Corporation.
  6 * Copyright (C) 2011 Becky Bruce, Freescale Semiconductor
  7 *
  8 */
  9#include <linux/mm.h>
 10#include <linux/hugetlb.h>
 11
 12#include <asm/mmu.h>
 13
 14#ifdef CONFIG_PPC64
 15#include <asm/paca.h>
 16
 17static inline int tlb1_next(void)
 18{
 19	struct paca_struct *paca = get_paca();
 20	struct tlb_core_data *tcd;
 21	int this, next;
 22
 23	tcd = paca->tcd_ptr;
 24	this = tcd->esel_next;
 25
 26	next = this + 1;
 27	if (next >= tcd->esel_max)
 28		next = tcd->esel_first;
 29
 30	tcd->esel_next = next;
 31	return this;
 32}
 33
 34static inline void book3e_tlb_lock(void)
 35{
 36	struct paca_struct *paca = get_paca();
 37	unsigned long tmp;
 38	int token = smp_processor_id() + 1;
 39
 40	/*
 41	 * Besides being unnecessary in the absence of SMT, this
 42	 * check prevents trying to do lbarx/stbcx. on e5500 which
 43	 * doesn't implement either feature.
 44	 */
 45	if (!cpu_has_feature(CPU_FTR_SMT))
 46		return;
 47
 48	asm volatile(".machine push;"
 49		     ".machine e6500;"
 50		     "1: lbarx %0, 0, %1;"
 51		     "cmpwi %0, 0;"
 52		     "bne 2f;"
 53		     "stbcx. %2, 0, %1;"
 54		     "bne 1b;"
 55		     "b 3f;"
 56		     "2: lbzx %0, 0, %1;"
 57		     "cmpwi %0, 0;"
 58		     "bne 2b;"
 59		     "b 1b;"
 60		     "3:"
 61		     ".machine pop;"
 62		     : "=&r" (tmp)
 63		     : "r" (&paca->tcd_ptr->lock), "r" (token)
 64		     : "memory");
 65}
 66
 67static inline void book3e_tlb_unlock(void)
 68{
 69	struct paca_struct *paca = get_paca();
 70
 71	if (!cpu_has_feature(CPU_FTR_SMT))
 72		return;
 73
 74	isync();
 75	paca->tcd_ptr->lock = 0;
 76}
 77#else
 78static inline int tlb1_next(void)
 79{
 80	int index, ncams;
 81
 82	ncams = mfspr(SPRN_TLB1CFG) & TLBnCFG_N_ENTRY;
 83
 84	index = this_cpu_read(next_tlbcam_idx);
 85
 86	/* Just round-robin the entries and wrap when we hit the end */
 87	if (unlikely(index == ncams - 1))
 88		__this_cpu_write(next_tlbcam_idx, tlbcam_index);
 89	else
 90		__this_cpu_inc(next_tlbcam_idx);
 91
 92	return index;
 93}
 94
 95static inline void book3e_tlb_lock(void)
 96{
 97}
 98
 99static inline void book3e_tlb_unlock(void)
100{
101}
102#endif
103
104static inline int book3e_tlb_exists(unsigned long ea, unsigned long pid)
105{
106	int found = 0;
107
108	mtspr(SPRN_MAS6, pid << 16);
109	asm volatile(
110		"tlbsx	0,%1\n"
111		"mfspr	%0,0x271\n"
112		"srwi	%0,%0,31\n"
113		: "=&r"(found) : "r"(ea));
114
115	return found;
116}
117
118static void
119book3e_hugetlb_preload(struct vm_area_struct *vma, unsigned long ea, pte_t pte)
120{
121	unsigned long mas1, mas2;
122	u64 mas7_3;
123	unsigned long psize, tsize, shift;
124	unsigned long flags;
125	struct mm_struct *mm;
126	int index;
127
128	if (unlikely(is_kernel_addr(ea)))
129		return;
130
131	mm = vma->vm_mm;
132
133	psize = vma_mmu_pagesize(vma);
134	shift = __ilog2(psize);
135	tsize = shift - 10;
136	/*
137	 * We can't be interrupted while we're setting up the MAS
138	 * registers or after we've confirmed that no tlb exists.
139	 */
140	local_irq_save(flags);
141
142	book3e_tlb_lock();
143
144	if (unlikely(book3e_tlb_exists(ea, mm->context.id))) {
145		book3e_tlb_unlock();
146		local_irq_restore(flags);
147		return;
148	}
149
150	/* We have to use the CAM(TLB1) on FSL parts for hugepages */
151	index = tlb1_next();
152	mtspr(SPRN_MAS0, MAS0_ESEL(index) | MAS0_TLBSEL(1));
153
154	mas1 = MAS1_VALID | MAS1_TID(mm->context.id) | MAS1_TSIZE(tsize);
155	mas2 = ea & ~((1UL << shift) - 1);
156	mas2 |= (pte_val(pte) >> PTE_WIMGE_SHIFT) & MAS2_WIMGE_MASK;
157	mas7_3 = (u64)pte_pfn(pte) << PAGE_SHIFT;
158	mas7_3 |= (pte_val(pte) >> PTE_BAP_SHIFT) & MAS3_BAP_MASK;
159	if (!pte_dirty(pte))
160		mas7_3 &= ~(MAS3_SW|MAS3_UW);
161
162	mtspr(SPRN_MAS1, mas1);
163	mtspr(SPRN_MAS2, mas2);
164
165	if (mmu_has_feature(MMU_FTR_BIG_PHYS))
166		mtspr(SPRN_MAS7, upper_32_bits(mas7_3));
167	mtspr(SPRN_MAS3, lower_32_bits(mas7_3));
168
169	asm volatile ("tlbwe");
170
171	book3e_tlb_unlock();
172	local_irq_restore(flags);
173}
174
175/*
176 * This is called at the end of handling a user page fault, when the
177 * fault has been handled by updating a PTE in the linux page tables.
178 *
179 * This must always be called with the pte lock held.
180 */
181void __update_mmu_cache(struct vm_area_struct *vma, unsigned long address, pte_t *ptep)
182{
183	if (is_vm_hugetlb_page(vma))
184		book3e_hugetlb_preload(vma, address, *ptep);
185}
186
187void flush_hugetlb_page(struct vm_area_struct *vma, unsigned long vmaddr)
188{
189	struct hstate *hstate = hstate_file(vma->vm_file);
190	unsigned long tsize = huge_page_shift(hstate) - 10;
191
192	__flush_tlb_page(vma->vm_mm, vmaddr, tsize, 0);
193}