cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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book3e_pgtable.c (3550B)

      1// SPDX-License-Identifier: GPL-2.0-or-later
      2/*
      3 * Copyright 2005, Paul Mackerras, IBM Corporation.
      4 * Copyright 2009, Benjamin Herrenschmidt, IBM Corporation.
      5 * Copyright 2015-2016, Aneesh Kumar K.V, IBM Corporation.
      6 */
      7
      8#include <linux/sched.h>
      9#include <linux/memblock.h>
     10#include <asm/pgalloc.h>
     11#include <asm/tlb.h>
     12#include <asm/dma.h>
     13#include <asm/code-patching.h>
     14
     15#include <mm/mmu_decl.h>
     16
     17#ifdef CONFIG_SPARSEMEM_VMEMMAP
     18/*
     19 * On Book3E CPUs, the vmemmap is currently mapped in the top half of
     20 * the vmalloc space using normal page tables, though the size of
     21 * pages encoded in the PTEs can be different
     22 */
     23int __meminit vmemmap_create_mapping(unsigned long start,
     24				     unsigned long page_size,
     25				     unsigned long phys)
     26{
     27	/* Create a PTE encoding without page size */
     28	unsigned long i, flags = _PAGE_PRESENT | _PAGE_ACCESSED |
     29		_PAGE_KERNEL_RW;
     30
     31	/* PTEs only contain page size encodings up to 32M */
     32	BUG_ON(mmu_psize_defs[mmu_vmemmap_psize].enc > 0xf);
     33
     34	/* Encode the size in the PTE */
     35	flags |= mmu_psize_defs[mmu_vmemmap_psize].enc << 8;
     36
     37	/* For each PTE for that area, map things. Note that we don't
     38	 * increment phys because all PTEs are of the large size and
     39	 * thus must have the low bits clear
     40	 */
     41	for (i = 0; i < page_size; i += PAGE_SIZE)
     42		BUG_ON(map_kernel_page(start + i, phys, __pgprot(flags)));
     43
     44	return 0;
     45}
     46
     47#ifdef CONFIG_MEMORY_HOTPLUG
     48void vmemmap_remove_mapping(unsigned long start,
     49			    unsigned long page_size)
     50{
     51}
     52#endif
     53#endif /* CONFIG_SPARSEMEM_VMEMMAP */
     54
     55static void __init *early_alloc_pgtable(unsigned long size)
     56{
     57	void *ptr;
     58
     59	ptr = memblock_alloc_try_nid(size, size, MEMBLOCK_LOW_LIMIT,
     60				     __pa(MAX_DMA_ADDRESS), NUMA_NO_NODE);
     61
     62	if (!ptr)
     63		panic("%s: Failed to allocate %lu bytes align=0x%lx max_addr=%lx\n",
     64		      __func__, size, size, __pa(MAX_DMA_ADDRESS));
     65
     66	return ptr;
     67}
     68
     69/*
     70 * map_kernel_page currently only called by __ioremap
     71 * map_kernel_page adds an entry to the ioremap page table
     72 * and adds an entry to the HPT, possibly bolting it
     73 */
     74int __ref map_kernel_page(unsigned long ea, unsigned long pa, pgprot_t prot)
     75{
     76	pgd_t *pgdp;
     77	p4d_t *p4dp;
     78	pud_t *pudp;
     79	pmd_t *pmdp;
     80	pte_t *ptep;
     81
     82	BUILD_BUG_ON(TASK_SIZE_USER64 > PGTABLE_RANGE);
     83	if (slab_is_available()) {
     84		pgdp = pgd_offset_k(ea);
     85		p4dp = p4d_offset(pgdp, ea);
     86		pudp = pud_alloc(&init_mm, p4dp, ea);
     87		if (!pudp)
     88			return -ENOMEM;
     89		pmdp = pmd_alloc(&init_mm, pudp, ea);
     90		if (!pmdp)
     91			return -ENOMEM;
     92		ptep = pte_alloc_kernel(pmdp, ea);
     93		if (!ptep)
     94			return -ENOMEM;
     95	} else {
     96		pgdp = pgd_offset_k(ea);
     97		p4dp = p4d_offset(pgdp, ea);
     98		if (p4d_none(*p4dp)) {
     99			pudp = early_alloc_pgtable(PUD_TABLE_SIZE);
    100			p4d_populate(&init_mm, p4dp, pudp);
    101		}
    102		pudp = pud_offset(p4dp, ea);
    103		if (pud_none(*pudp)) {
    104			pmdp = early_alloc_pgtable(PMD_TABLE_SIZE);
    105			pud_populate(&init_mm, pudp, pmdp);
    106		}
    107		pmdp = pmd_offset(pudp, ea);
    108		if (!pmd_present(*pmdp)) {
    109			ptep = early_alloc_pgtable(PTE_TABLE_SIZE);
    110			pmd_populate_kernel(&init_mm, pmdp, ptep);
    111		}
    112		ptep = pte_offset_kernel(pmdp, ea);
    113	}
    114	set_pte_at(&init_mm, ea, ptep, pfn_pte(pa >> PAGE_SHIFT, prot));
    115
    116	smp_wmb();
    117	return 0;
    118}
    119
    120void __patch_exception(int exc, unsigned long addr)
    121{
    122	unsigned int *ibase = &interrupt_base_book3e;
    123
    124	/*
    125	 * Our exceptions vectors start with a NOP and -then- a branch
    126	 * to deal with single stepping from userspace which stops on
    127	 * the second instruction. Thus we need to patch the second
    128	 * instruction of the exception, not the first one.
    129	 */
    130
    131	patch_branch(ibase + (exc / 4) + 1, addr, 0);
    132}