src/security/memory/memory_clear.c

   1 /* SPDX-License-Identifier: GPL-2.0-only */
   2
   3 #if ENV_X86
   4 #include <cpu/x86/pae.h>
   5 #else
   6 #define memset_pae(a, b, c, d, e) 0
   7 #define PAE_PGTL_ALIGN 0
   8 #define PAE_PGTL_SIZE 0
   9 #define PAE_VMEM_ALIGN 0
  10 #define PAE_VMEM_SIZE 0
  11 #endif
  12
  13 #include <memrange.h>
  14 #include <bootmem.h>
  15 #include <bootstate.h>
  16 #include <symbols.h>
  17 #include <console/console.h>
  18 #include <arch/memory_clear.h>
  19 #include <string.h>
  20 #include <security/memory/memory.h>
  21 #include <cbmem.h>
  22 #include <acpi/acpi.h>
  23 #include <drivers/efi/capsules.h>
  24
  25 /* Helper to find free space for memset_pae. */
  26 static uintptr_t get_free_memory_range(struct memranges *mem,
  27                                        const resource_t align,
  28                                        const resource_t size)
  29 {
  30         const struct range_entry *r;
  31
  32         /* Find a spot for virtual memory address */
  33         memranges_each_entry(r, mem) {
  34                 if (range_entry_tag(r) != BM_MEM_RAM)
  35                         continue;
  36
  37                 if (ALIGN_UP(range_entry_base(r) + size, align) + size >
  38                     range_entry_end(r))
  39                         continue;
  40
  41                 return ALIGN_UP(range_entry_base(r) + size, align);
  42         }
  43         printk(BIOS_ERR, "%s: Couldn't find free memory range\n", __func__);
  44
  45         return 0;
  46 }
  47
  48 /*
  49  * Clears all memory regions marked as BM_MEM_RAM.
  50  * Uses memset_pae if the memory region can't be accessed by memset and
  51  * architecture is x86.
  52  *
  53  * @return 0 on success, 1 on error
  54  */
  55 static void clear_memory(void *unused)
  56 {
  57         const struct range_entry *r;
  58         struct memranges mem;
  59         uintptr_t pgtbl, vmem_addr;
  60
  61         if (acpi_is_wakeup_s3())
  62                 return;
  63
  64         /* Process capsules before clearing memory and only if not waking up from S3. */
  65         efi_parse_capsules();
  66
  67         if (!security_clear_dram_request())
  68                 return;
  69
  70         /* FSP1.0 is marked as MMIO and won't appear here */
  71
  72         memranges_init(&mem, IORESOURCE_MEM | IORESOURCE_FIXED |
  73                         IORESOURCE_STORED | IORESOURCE_ASSIGNED |
  74                         IORESOURCE_CACHEABLE,
  75                         IORESOURCE_MEM | IORESOURCE_FIXED |
  76                         IORESOURCE_STORED | IORESOURCE_ASSIGNED |
  77                         IORESOURCE_CACHEABLE,
  78                         BM_MEM_RAM);
  79
  80         /* Add reserved entries */
  81         void *baseptr;
  82         size_t size;
  83
  84         /* Only skip CBMEM, stage program, stack and heap are included there. */
  85
  86         if (cbmem_get_region(&baseptr, &size))
  87                 die("Could not find cbmem region");
  88         memranges_insert(&mem, (uintptr_t)baseptr, size, BM_MEM_TABLE);
  89
  90         if (ENV_X86) {
  91                 /* Find space for PAE enabled memset */
  92                 pgtbl = get_free_memory_range(&mem, PAE_PGTL_ALIGN, PAE_PGTL_SIZE);
  93
  94                 /* Don't touch page tables while clearing */
  95                 memranges_insert(&mem, pgtbl, PAE_PGTL_SIZE, BM_MEM_TABLE);
  96
  97                 vmem_addr = get_free_memory_range(&mem, PAE_VMEM_ALIGN, PAE_VMEM_SIZE);
  98
  99                 printk(BIOS_SPEW, "%s: pgtbl at %p, virt memory at %p\n",
 100                 __func__, (void *)pgtbl, (void *)vmem_addr);
 101         }
 102
 103         /* Now clear all usable DRAM */
 104         memranges_each_entry(r, &mem) {
 105                 if (range_entry_tag(r) != BM_MEM_RAM)
 106                         continue;
 107                 printk(BIOS_DEBUG, "%s: Clearing DRAM %016llx-%016llx\n",
 108                        __func__, range_entry_base(r), range_entry_end(r));
 109
 110                 /* Does regular memset work? */
 111                 if (sizeof(resource_t) == sizeof(void *) ||
 112                     !(range_entry_end(r) >> (sizeof(void *) * 8))) {
 113                         /* fastpath */
 114                         memset((void *)(uintptr_t)range_entry_base(r), 0,
 115                                range_entry_size(r));
 116                 }
 117                 /* Use PAE if available */
 118                 else if (ENV_X86) {
 119                         if (memset_pae(range_entry_base(r), 0,
 120                             range_entry_size(r), (void *)pgtbl,
 121                             (void *)vmem_addr))
 122                                 printk(BIOS_ERR, "%s: Failed to memset "
 123                                        "memory\n", __func__);
 124                 } else {
 125                         printk(BIOS_ERR, "%s: Failed to memset memory\n",
 126                                __func__);
 127                 }
 128         }
 129
 130         if (ENV_X86) {
 131                 /* Clear previously skipped memory reserved for pagetables */
 132                 printk(BIOS_DEBUG, "%s: Clearing DRAM %016lx-%016lx\n",
 133                 __func__, pgtbl, pgtbl + PAE_PGTL_SIZE);
 134
 135                 memset((void *)pgtbl, 0, PAE_PGTL_SIZE);
 136         }
 137
 138         memranges_teardown(&mem);
 139 }
 140
 141 /* After DEV_INIT as MTRRs needs to be configured on x86 */
 142 BOOT_STATE_INIT_ENTRY(BS_DEV_INIT, BS_ON_EXIT, clear_memory, NULL);