arch/arm/plat-samsung/pm-check.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 //
   3 // originally in linux/arch/arm/plat-s3c24xx/pm.c
   4 //
   5 // Copyright (c) 2004-2008 Simtec Electronics
   6 //      http://armlinux.simtec.co.uk
   7 //      Ben Dooks <ben@simtec.co.uk>
   8 //
   9 // S3C Power Mangament - suspend/resume memory corruption check.
  10
  11 #include <linux/kernel.h>
  12 #include <linux/suspend.h>
  13 #include <linux/init.h>
  14 #include <linux/crc32.h>
  15 #include <linux/ioport.h>
  16 #include <linux/slab.h>
  17
  18 #include <plat/pm-common.h>
  19
  20 #if CONFIG_SAMSUNG_PM_CHECK_CHUNKSIZE < 1
  21 #error CONFIG_SAMSUNG_PM_CHECK_CHUNKSIZE must be a positive non-zero value
  22 #endif
  23
  24 /* suspend checking code...
  25  *
  26  * this next area does a set of crc checks over all the installed
  27  * memory, so the system can verify if the resume was ok.
  28  *
  29  * CONFIG_SAMSUNG_PM_CHECK_CHUNKSIZE defines the block-size for the CRC,
  30  * increasing it will mean that the area corrupted will be less easy to spot,
  31  * and reducing the size will cause the CRC save area to grow
  32 */
  33
  34 #define CHECK_CHUNKSIZE (CONFIG_SAMSUNG_PM_CHECK_CHUNKSIZE * 1024)
  35
  36 static u32 crc_size;    /* size needed for the crc block */
  37 static u32 *crcs;       /* allocated over suspend/resume */
  38
  39 typedef u32 *(run_fn_t)(struct resource *ptr, u32 *arg);
  40
  41 /* s3c_pm_run_res
  42  *
  43  * go through the given resource list, and look for system ram
  44 */
  45
  46 static void s3c_pm_run_res(struct resource *ptr, run_fn_t fn, u32 *arg)
  47 {
  48         while (ptr != NULL) {
  49                 if (ptr->child != NULL)
  50                         s3c_pm_run_res(ptr->child, fn, arg);
  51
  52                 if ((ptr->flags & IORESOURCE_SYSTEM_RAM)
  53                                 == IORESOURCE_SYSTEM_RAM) {
  54                         S3C_PMDBG("Found system RAM at %08lx..%08lx\n",
  55                                   (unsigned long)ptr->start,
  56                                   (unsigned long)ptr->end);
  57                         arg = (fn)(ptr, arg);
  58                 }
  59
  60                 ptr = ptr->sibling;
  61         }
  62 }
  63
  64 static void s3c_pm_run_sysram(run_fn_t fn, u32 *arg)
  65 {
  66         s3c_pm_run_res(&iomem_resource, fn, arg);
  67 }
  68
  69 static u32 *s3c_pm_countram(struct resource *res, u32 *val)
  70 {
  71         u32 size = (u32)resource_size(res);
  72
  73         size += CHECK_CHUNKSIZE-1;
  74         size /= CHECK_CHUNKSIZE;
  75
  76         S3C_PMDBG("Area %08lx..%08lx, %d blocks\n",
  77                   (unsigned long)res->start, (unsigned long)res->end, size);
  78
  79         *val += size * sizeof(u32);
  80         return val;
  81 }
  82
  83 /* s3c_pm_prepare_check
  84  *
  85  * prepare the necessary information for creating the CRCs. This
  86  * must be done before the final save, as it will require memory
  87  * allocating, and thus touching bits of the kernel we do not
  88  * know about.
  89 */
  90
  91 void s3c_pm_check_prepare(void)
  92 {
  93         crc_size = 0;
  94
  95         s3c_pm_run_sysram(s3c_pm_countram, &crc_size);
  96
  97         S3C_PMDBG("s3c_pm_prepare_check: %u checks needed\n", crc_size);
  98
  99         crcs = kmalloc(crc_size+4, GFP_KERNEL);
 100         if (crcs == NULL)
 101                 printk(KERN_ERR "Cannot allocated CRC save area\n");
 102 }
 103
 104 static u32 *s3c_pm_makecheck(struct resource *res, u32 *val)
 105 {
 106         unsigned long addr, left;
 107
 108         for (addr = res->start; addr < res->end;
 109              addr += CHECK_CHUNKSIZE) {
 110                 left = res->end - addr;
 111
 112                 if (left > CHECK_CHUNKSIZE)
 113                         left = CHECK_CHUNKSIZE;
 114
 115                 *val = crc32_le(~0, phys_to_virt(addr), left);
 116                 val++;
 117         }
 118
 119         return val;
 120 }
 121
 122 /* s3c_pm_check_store
 123  *
 124  * compute the CRC values for the memory blocks before the final
 125  * sleep.
 126 */
 127
 128 void s3c_pm_check_store(void)
 129 {
 130         if (crcs != NULL)
 131                 s3c_pm_run_sysram(s3c_pm_makecheck, crcs);
 132 }
 133
 134 /* in_region
 135  *
 136  * return TRUE if the area defined by ptr..ptr+size contains the
 137  * what..what+whatsz
 138 */
 139
 140 static inline int in_region(void *ptr, int size, void *what, size_t whatsz)
 141 {
 142         if ((what+whatsz) < ptr)
 143                 return 0;
 144
 145         if (what > (ptr+size))
 146                 return 0;
 147
 148         return 1;
 149 }
 150
 151 /**
 152  * s3c_pm_runcheck() - helper to check a resource on restore.
 153  * @res: The resource to check
 154  * @vak: Pointer to list of CRC32 values to check.
 155  *
 156  * Called from the s3c_pm_check_restore() via s3c_pm_run_sysram(), this
 157  * function runs the given memory resource checking it against the stored
 158  * CRC to ensure that memory is restored. The function tries to skip as
 159  * many of the areas used during the suspend process.
 160  */
 161 static u32 *s3c_pm_runcheck(struct resource *res, u32 *val)
 162 {
 163         unsigned long addr;
 164         unsigned long left;
 165         void *stkpage;
 166         void *ptr;
 167         u32 calc;
 168
 169         stkpage = (void *)((u32)&calc & ~PAGE_MASK);
 170
 171         for (addr = res->start; addr < res->end;
 172              addr += CHECK_CHUNKSIZE) {
 173                 left = res->end - addr;
 174
 175                 if (left > CHECK_CHUNKSIZE)
 176                         left = CHECK_CHUNKSIZE;
 177
 178                 ptr = phys_to_virt(addr);
 179
 180                 if (in_region(ptr, left, stkpage, 4096)) {
 181                         S3C_PMDBG("skipping %08lx, has stack in\n", addr);
 182                         goto skip_check;
 183                 }
 184
 185                 if (in_region(ptr, left, crcs, crc_size)) {
 186                         S3C_PMDBG("skipping %08lx, has crc block in\n", addr);
 187                         goto skip_check;
 188                 }
 189
 190                 /* calculate and check the checksum */
 191
 192                 calc = crc32_le(~0, ptr, left);
 193                 if (calc != *val) {
 194                         printk(KERN_ERR "Restore CRC error at "
 195                                "%08lx (%08x vs %08x)\n", addr, calc, *val);
 196
 197                         S3C_PMDBG("Restore CRC error at %08lx (%08x vs %08x)\n",
 198                             addr, calc, *val);
 199                 }
 200
 201         skip_check:
 202                 val++;
 203         }
 204
 205         return val;
 206 }
 207
 208 /**
 209  * s3c_pm_check_restore() - memory check called on resume
 210  *
 211  * check the CRCs after the restore event and free the memory used
 212  * to hold them
 213 */
 214 void s3c_pm_check_restore(void)
 215 {
 216         if (crcs != NULL)
 217                 s3c_pm_run_sysram(s3c_pm_runcheck, crcs);
 218 }
 219
 220 /**
 221  * s3c_pm_check_cleanup() - free memory resources
 222  *
 223  * Free the resources that where allocated by the suspend
 224  * memory check code. We do this separately from the
 225  * s3c_pm_check_restore() function as we cannot call any
 226  * functions that might sleep during that resume.
 227  */
 228 void s3c_pm_check_cleanup(void)
 229 {
 230         kfree(crcs);
 231         crcs = NULL;
 232 }
 233