More loader code, not finished yet.

git-svn-id: svn://svn.code.sf.net/p/chibios/svn/trunk@15318 27425a3e-05d8-49a3-a47f-9c15f0e5edd8

os/sb/host/sbelf.c

@@ -36,6 +36,16 @@
 /* Module local definitions.                                                 */
 /*===========================================================================*/
 
+/* Relevant section types.*/
+#define SHT_PROGBITS        1U
+#define SHT_REL             9U
+
+/* Relevant section flags.*/
+#define SHF_WRITE           (1U << 0)
+#define SHF_ALLOC           (1U << 1)
+#define SHF_EXECINSTR       (1U << 2)
+#define SHF_INFO_LINK       (1U << 6)
+
 /*===========================================================================*/
 /* Module exported variables.                                                */
 /*===========================================================================*/
@@ -56,6 +66,7 @@ typedef struct elf_load_context {
   uint16_t                  shnum;
   vfs_offset_t              shoff;
   vfs_offset_t              stringsoff;
+  uint64_t                  loaded;
 } elf_load_context_t;
 
 /**
@@ -95,12 +106,65 @@ typedef struct {
 /* Module local variables.                                                   */
 /*===========================================================================*/
 
-
 /*===========================================================================*/
 /* Module local functions.                                                   */
 /*===========================================================================*/
 
+#if 0
+static msg_t read_section_name(elf_load_context_t *ctxp,
+                               elf32_section_header_t *shp,
+                               char *buf, size_t buflen) {
+  msg_t ret;
+
+  if (shp->sh_name == 0U) {
+    *buf = '\0';
+    return CH_RET_SUCCESS;
+  }
+
+  ret = vfsSetFilePosition(ctxp->fnp,
+                           ctxp->stringsoff + (vfs_offset_t)shp->sh_name,
+                           VFS_SEEK_SET);
+  CH_RETURN_ON_ERROR(ret);
+  ret = vfsReadFile(ctxp->fnp, (void *)buf, buflen);
+  CH_RETURN_ON_ERROR(ret);
+
+  return CH_RET_SUCCESS;
+}
+#endif
+
+static msg_t read_section_header(elf_load_context_t *ctxp,
+                                 elf32_section_header_t *shp,
+                                 unsigned index) {
+  msg_t ret;
+
+  ret = vfsSetFilePosition(ctxp->fnp,
+                           ctxp->shoff + ((vfs_offset_t)index *
+                                          (vfs_offset_t)sizeof (elf32_section_header_t)),
+                           VFS_SEEK_SET);
+  CH_RETURN_ON_ERROR(ret);
+  return vfsReadFile(ctxp->fnp, (void *)shp, sizeof (elf32_section_header_t));
+}
+
+static msg_t load_section(elf_load_context_t *ctxp,
+                          elf32_section_header_t *shp) {
+
+  (void)ctxp;
+  (void)shp;
+
+  return CH_RET_SUCCESS;
+}
+
+static msg_t reloc_section(elf_load_context_t *ctxp,
+                           elf32_section_header_t *shp) {
+
+  (void)ctxp;
+  (void)shp;
+
+  return CH_RET_SUCCESS;
+}
+
 static msg_t init_elf_context(elf_load_context_t *ctxp,
+                              elf32_section_header_t *shp,
                               vfs_file_node_c *fnp,
                               memory_area_t *map) {
   static uint8_t elf32_header[16] = {
@@ -108,9 +172,10 @@ static msg_t init_elf_context(elf_load_context_t *ctxp,
     0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
   };
   elf32_header_t h;
-  elf32_section_header_t sh;
   msg_t ret;
 
+  memset((void *)ctxp, 0, sizeof (elf_load_context_t));
+
   /* Initializing the fixed part of the context.*/
   ctxp->fnp  = fnp;
   ctxp->map  = map;
@@ -129,20 +194,14 @@ static msg_t init_elf_context(elf_load_context_t *ctxp,
 
   /* TODO more consistency checks.*/
 
-  /* Reading the header of the section containing the section names.*/
-  ret = vfsSetFilePosition(ctxp->fnp,
-                           (vfs_offset_t)(h.e_shoff +
-                                         (h.e_shstrndx * sizeof (elf32_section_header_t))),
-                           VFS_SEEK_SET);
-  CH_RETURN_ON_ERROR(ret);
-  ret = vfsReadFile(ctxp->fnp, (void *)&sh, sizeof (elf32_section_header_t));
-  CH_RETURN_ON_ERROR(ret);
-
   /* Storing info required later.*/
   ctxp->entry       = h.e_entry;
   ctxp->shnum       = h.e_shnum;
   ctxp->shoff       = (vfs_offset_t)h.e_shoff;
-  ctxp->stringsoff  = (vfs_offset_t)sh.sh_offset;
+
+  /* Reading the header of the section containing the section names.*/
+  ret = read_section_header(ctxp, shp, (unsigned)h.e_shstrndx);
+  ctxp->stringsoff  = (vfs_offset_t)shp->sh_offset;
 
   return CH_RET_SUCCESS;
 }
@@ -151,23 +210,88 @@ static msg_t init_elf_context(elf_load_context_t *ctxp,
 /* Module exported functions.                                                */
 /*===========================================================================*/
 
-msg_t sbElfLoad(vfs_driver_c *drvp, const char *path, memory_area_t *map) {
+msg_t sbElfLoad(vfs_file_node_c *fnp, memory_area_t *map) {
+  elf_load_context_t ctx;
+  elf32_section_header_t sh;
+  unsigned i;
+  msg_t ret;
+
+  do {
+    ret = init_elf_context(&ctx, &sh, fnp, map);
+    CH_BREAK_ON_ERROR(ret);
+
+    /* Iterating through sections.*/
+    for (i = 0U; i < (unsigned)ctx.shnum; i++) {
+//      char name[8];
+
+      ret = read_section_header(&ctx, &sh, i);
+      CH_BREAK_ON_ERROR(ret);
+
+#if 0
+      ret = read_section_name(&ctx, &sh, name, sizeof name);
+      CH_BREAK_ON_ERROR(ret);
+
+      /* Handling the various sections.*/
+      if (strcmp(name, ".text") == (size_t)0) {
+        ret = load_section(&ctx, &sh, i);
+      }
+      else if (strcmp(name, ".rodata") == (size_t)0) {
+        ret = load_section(&ctx, &sh, i);
+      }
+      else if (strcmp(name, ".data") == (size_t)0) {
+        ret = load_section(&ctx, &sh, i);
+      }
+      else if (strcmp(name, ".bss") == (size_t)0) {
+
+      }
+#endif
+
+      /* Sections to be loaded.*/
+      if ((sh.sh_type == SHT_PROGBITS) && ((sh.sh_flags & SHF_ALLOC) != 0U)) {
+
+        /* Loading sections with index greater than 63 is not supported.*/
+        if (i >= 64U) {
+          return CH_RET_ENOMEM;
+        }
+
+        ret = load_section(&ctx, &sh);
+        CH_RETURN_ON_ERROR(ret);
+
+        ctx.loaded |= (1ULL << i);
+      }
+
+      /* Sections to be relocated, must refer to a loaded section.*/
+      if ((sh.sh_type == SHT_REL) &&
+          ((sh.sh_flags & SHF_INFO_LINK) != 0U) &&
+          ((ctx.loaded & (1ULL << sh.sh_info)) != 0ULL)) {
+
+        ret = reloc_section(&ctx, &sh);
+        CH_RETURN_ON_ERROR(ret);
+
+      }
+    }
+
+  } while (false);
+
+  return ret;
+}
+
+msg_t sbElfLoadFile(vfs_driver_c *drvp, const char *path, memory_area_t *map) {
   vfs_file_node_c *fnp;
   msg_t ret;
-  elf_load_context_t ctx;
 
   ret = vfsDrvOpenFile(drvp, path, VO_RDONLY, &fnp);
   CH_RETURN_ON_ERROR(ret);
 
   do {
-    ret = init_elf_context(&ctx, fnp, map);
+    ret = sbElfLoad(fnp, map);
     CH_BREAK_ON_ERROR(ret);
 
   } while (false);
 
   vfsClose((vfs_node_c *)fnp);
 
-  return CH_RET_SUCCESS;
+  return ret;
 }
 
 #endif /* SB_CFG_ENABLE_VFS == TRUE */

os/sb/host/sbelf.h

@@ -57,7 +57,8 @@
 #ifdef __cplusplus
 extern "C" {
 #endif
-  msg_t sbElfLoad(vfs_driver_c *drvp, const char *path, memory_area_t *map);
+  msg_t sbElfLoad(vfs_file_node_c *fnp, memory_area_t *map);
+  msg_t sbElfLoadFile(vfs_driver_c *drvp, const char *path, memory_area_t *map);
 #ifdef __cplusplus
 }
 #endif