mm.c

#include <errno.h>
#include <stdio.h>
#include <string.h>
#include <sys/system_properties.h>

#include "kallsyms.h"
#include "mm.h"

typedef struct _supported_device {
  const char *device;
  const char *build_id;
  unsigned long int remap_pfn_range_address;
} supported_device;

static supported_device supported_devices[] = {
  { "IS17SH", "01.00.04",           0xc0208a34 },
  { "SH-04E", "01.00.02",           0xc00e458c },
  { "SOL21",  "9.1.D.0.395",        0xc010e33c },
  { "HTL21",  "JRO03C",             0xc00ff32c },
  { "SC-04E", "JDQ39.SC04EOMUAMDI", 0xc011383c },
  { "SC-04E", "JDQ39.SC04EOMUAMF1", 0xc01138a4 },
  { "SC-04E", "JDQ39.SC04EOMUAMF2", 0xc01138a0 },
  { "SC-04E", "JDQ39.SC04EOMUAMG2", 0xc01138a8 },
};

static int n_supported_devices = sizeof(supported_devices) / sizeof(supported_devices[0]);

unsigned long int
_get_remap_pfn_range_address(void)
{
  int i;
  char device[PROP_VALUE_MAX];
  char build_id[PROP_VALUE_MAX];

  __system_property_get("ro.product.model", device);
  __system_property_get("ro.build.display.id", build_id);

  for (i = 0; i < n_supported_devices; i++) {
    if (!strcmp(device, supported_devices[i].device) &&
        !strcmp(build_id, supported_devices[i].build_id)) {
      return supported_devices[i].remap_pfn_range_address;
    }
  }

  printf("%s (%s) is not supported.\n", device, build_id);

  return 0;
}

void *
get_remap_pfn_range_address(void)
{
  if (kallsyms_exist()) {
    return kallsyms_get_symbol_address("remap_pfn_range");
  }
  return (void*)_get_remap_pfn_range_address();
}

static unsigned long int kernel_phys_offset = 0;

void
set_kernel_phys_offset(unsigned long int offset)
{
  kernel_phys_offset = offset;
}

#define PAGE_SHIFT  12

int
ptmx_mmap(struct file *filep, struct vm_area_struct *vma)
{
  return remap_pfn_range(vma, vma->vm_start,
                         kernel_phys_offset >> PAGE_SHIFT,
                         vma->vm_end - vma->vm_start, vma->vm_page_prot);
}