[v0.89][ARM] Separate udev for ARM in a different file, since there are many functions that are ARM only. Refactoring of file reading code

src/arm/udev.c

@@ -0,0 +1,161 @@
+#include "udev.h"
+#include "midr.h"
+
+#define _PATH_CPUS_PRESENT           _PATH_SYS_SYSTEM _PATH_SYS_CPU "/present"
+#define _PATH_CPUINFO                "/proc/cpuinfo"
+
+#define CPUINFO_CPU_IMPLEMENTER_STR  "CPU implementer\t: "
+#define CPUINFO_CPU_ARCHITECTURE_STR "CPU architecture: "
+#define CPUINFO_CPU_VARIANT_STR      "CPU variant\t: "
+#define CPUINFO_CPU_PART_STR         "CPU part\t: "
+#define CPUINFO_CPU_REVISION_STR     "CPU revision\t: "
+#define CPUINFO_HARDWARE_STR         "Hardware\t: "
+
+#define CPUINFO_CPU_STRING "processor"
+
+// https://www.kernel.org/doc/html/latest/core-api/cpu_hotplug.html
+int get_ncores_from_cpuinfo() {
+  // Examples:
+  // 0-271
+  // 0-5
+  // 0-7
+  int filelen;
+  char* buf;
+  if((buf = read_file(_PATH_CPUS_PRESENT, &filelen)) == NULL) {
+    perror("open");
+    return UNKNOWN;    
+  }
+  
+  int ncores = 0;
+  char* tmp1 = strstr(buf, "-") + 1;
+  char* tmp2 = strstr(buf, "\n");
+  char ncores_str[filelen];
+  memset(ncores_str, 0, sizeof(char) * filelen);
+  memcpy(ncores_str, tmp1, tmp2-tmp1);
+  
+  char* end;
+  errno = 0;
+  ncores = strtol(ncores_str, &end, 10) + 1;  
+  if(errno != 0) {
+    perror("strtol");
+    return UNKNOWN;
+  }
+
+  free(buf);
+
+  return ncores;
+}
+
+long parse_cpuinfo_field(char* buf, char* field_str, int field_base) {
+  char* tmp = strstr(buf, field_str);
+  if(tmp == NULL) return -1;
+  tmp += strlen(field_str);
+
+  char* end;
+  errno = 0;
+  long ret = strtol(tmp, &end, field_base);
+  if(errno != 0) {
+    perror("strtol");
+    return -1;
+  }
+
+  return ret;
+}
+// https://developer.arm.com/docs/ddi0595/h/aarch32-system-registers/midr
+// https://static.docs.arm.com/ddi0595/h/SysReg_xml_v86A-2020-06.pdf
+uint32_t get_midr_from_cpuinfo(uint32_t core, bool* success) {
+  int filelen;
+  char* buf;
+  *success = true;
+  if((buf = read_file(_PATH_CPUINFO, &filelen)) == NULL) {
+    perror("open");
+    *success = false;     
+    return 0;    
+  }
+
+  char* tmp = buf;
+  uint32_t current_core = 0;
+  while(core != current_core && tmp != NULL) {
+    tmp++;
+    current_core++;
+    tmp = strstr(tmp, CPUINFO_CPU_STRING);
+  }
+  
+  if(tmp == NULL) {
+    *success = false;    
+    return 0;
+  }
+
+  uint32_t cpu_implementer;
+  uint32_t cpu_architecture;
+  uint32_t cpu_variant;
+  uint32_t cpu_part;
+  uint32_t cpu_revision;
+  uint32_t midr = 0;
+  long ret;
+
+  if ((ret = parse_cpuinfo_field(tmp, CPUINFO_CPU_IMPLEMENTER_STR, 16)) < 0) {
+    printf("Failed parsing cpu_implementer\n");
+    *success = false;    
+    return 0;
+  }
+  cpu_implementer = (uint32_t) ret;
+
+  if ((ret = parse_cpuinfo_field(tmp, CPUINFO_CPU_ARCHITECTURE_STR, 10)) < 0) {
+    printf("Failed parsing cpu_architecture\n");
+    *success = false;    
+    return 0;
+  }
+  cpu_architecture = (uint32_t) 0xF; // Why?
+
+  if ((ret = parse_cpuinfo_field(tmp, CPUINFO_CPU_VARIANT_STR, 16)) < 0) {
+    printf("Failed parsing cpu_variant\n");
+    *success = false;    
+    return 0;
+  }
+  cpu_variant = (uint32_t) ret;
+
+  if ((ret = parse_cpuinfo_field(tmp, CPUINFO_CPU_PART_STR, 16)) < 0) {
+    printf("Failed parsing cpu_part\n");
+    *success = false;    
+    return 0;
+  }
+  cpu_part = (uint32_t) ret;
+
+  if ((ret = parse_cpuinfo_field(tmp, CPUINFO_CPU_REVISION_STR, 10)) < 0) {
+    printf("Failed parsing cpu_revision\n");
+    *success = false;    
+    return 0;
+  }
+  cpu_revision = (uint32_t) ret;
+
+  midr = midr_set_implementer(midr, cpu_implementer);
+  midr = midr_set_variant(midr, cpu_variant);
+  midr = midr_set_architecture(midr, cpu_architecture);
+  midr = midr_set_part(midr, cpu_part);
+  midr = midr_set_revision(midr, cpu_revision);
+
+  return midr;
+}
+
+char* get_hardware_from_cpuinfo() {
+  int filelen;
+  char* buf;
+  if((buf = read_file(_PATH_CPUINFO, &filelen)) == NULL) {
+    perror("open");
+    return NULL;    
+  }
+  
+  char* tmp1 = strstr(buf, CPUINFO_HARDWARE_STR);
+  if(tmp1 == NULL) return NULL;
+  tmp1 = tmp1 + strlen(CPUINFO_HARDWARE_STR);
+  char* tmp2 = strstr(tmp1, "\n");
+  
+  int strlen = (1 + (tmp2-tmp1));
+  char* hardware = malloc(sizeof(char) * strlen);
+  memset(hardware, 0, sizeof(char) * strlen);
+  strncpy(hardware, tmp1, tmp2-tmp1);
+  
+  return hardware;
+}
+