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