libs/libc/modlib: fix dynamic loader issues

* build-globals.sh
    - Macros for defining symbols etc. based on assembler in use
    - Use the System.map to get all the nuttx symbols

  * libs/libc/modlib/modlib_globals.S
    - Provide an empty skeleton. If the dynamic loading functions
      are required then run build-global.sh after a clean build
      using the skeleton. This will fill out the skeleton with the
      symbols to be available to dynamically loaded modules.

  * libs/libc/modlib/modlib_loadhdrs.c
    - Fix case where there are no program headers are avaiable

build-globals.sh

@@ -13,6 +13,8 @@ findEP()
 	SIZE=${#SYM[@]}
 	L=0
 	R=$((SIZE - 1))
+	OLDL=99999999
+	OLDR=99999999
 	while [ ${L} -le ${R} ]
 	do
 		T=$(( L + R ))
@@ -26,6 +28,11 @@ findEP()
 		else
 			R=$(( M - 1 ))
 		fi
+		if [ ${OLDL} -eq ${L} -a ${OLDR} -eq ${R} ]; then
+			: return 0
+		fi
+		OLDL=${L}
+		OLDR=${R}
 	done
 	return 0
 }
@@ -38,30 +45,36 @@ getEP()
 {
 	for ((i = 0; i < ${#OBJ[@]}; i++))
 	do
-		FUNCS=`${NM} -g --defined-only ../staging/${OBJ[$i]} | awk '{print $3}' | sort | grep -Ev ${FILTER}`
+		if [ -f staging/${OBJ[$i]} ]; then
-		FUNC=(${FUNCS})
+			FUNCS=`${NM} -g --defined-only staging/${OBJ[$i]} 2>/dev/null | grep "^0" | awk '{print $3}' | sort | grep -Ev ${FILTER}`
-		for ((j = 0; j < ${#FUNC[@]}; j++))
+			FUNC=(${FUNCS})
-		do
+			for ((j = 0; j < ${#FUNC[@]}; j++))
-			findEP ${FUNC[$j]}
+			do
-			if [ $? -eq 1 ]; then
+				findEP ${FUNC[$j]}
-				EP[${I_EP}]=${FUNC[$j]}
+				if [ $? -eq 1 ]; then
-				I_EP=$((I_EP + 1))
+					EP[${I_EP}]=${FUNC[$j]}
-			fi
+					I_EP=$((I_EP + 1))
-		done
+				fi
+			done
+		fi
 	done 
 }
 	
 #
 # Symbols to ignore within the NuttX libraries
 #
-FILTER="^lib_low|^FUNCTION|^STUB|^__start|^_vect|^arm_|^arp_|^bch|^binfmt|^blake|^block_|^cdcacm|^chksum|^clock_|^close_|^crypto_|^devif_|^devnull|^devuran|^devzero|^emerg|^epoll_|^elf_|^_dbgR|^dq_|^env_|^file_|^files_|^fs_|^ftl_|^g_|^get_|^group_|^global|^hcom|^i2c_|^inode_|^iob_|^irq_|^kmm_|^lfs_|^lib_|^local_|^mm_|^modlib_|^mpu_|^mq_|^nGlobals|^net_|^netdev_|^nx|^pipecommon|^posix_spawn_file|^psock_|^ramlog|^rammap|^readline_|^register_|^sched_|^sockfd|^spawn_|^sq_|^stm32|^symtab_|^syslog_|^syslogstream|^task_|^tcp_|^timer_|^uart_|^ub[12]|^udp_|^umm_|^umount|^unload_|^unregister|^up_|^usb|^usrsock_|^watchdog|^wd_"
+FILTER="^lib_low|^FUNCTION|^STUB|^__start|^_vect|^arm_|^arp_|^bch|^binfmt|^blake|^block_|^cdcacm|^chksum|^clock_|^close_|^crypto_|^devif_|^devnull|^devuran|^devzero|^emerg|^epoll_|^elf_|^_dbgR|^dq_|^env_|^file_|^files_|^fs_|^ftl_|^g_|^get_|^group_|^global|^hcom|^i2c_|^inode_|^iob_|^irq_|^kmm_|^lfs_|^lib_|^local_|^mm_|^modlib_|^mpu_|^mq_|^nGlobals|^net_|^netdev_|^nx|^pipecommon|^posix_spawn_file|^psock_|^ramlog|^rammap|^readline_|^register_|^sched_|^sockfd|^spawn_|^sq_|^stm32|^symtab_|^syslog_|^syslogstream|^task_|^tcp_|^timer_|^uart_|^ub[12]|^udp_|^umm_|^umount|^unload_|^unregister|^up_|^usb|^usrsock_|^watchdog|^wd_|globalNames$|nGlobals$|globalTable$|^\.l"
+
+if [ -z "${NM}" ]; then
+	NM="nm"
+fi
 
 #
 # Extract symbols from the runtime
 #
-SYMS=`${NM} ../nuttx | awk '{print $3}' | sort | grep -Ev ${FILTER}`
+SYMS=`cat System.map | awk '{print $3}' | sort | grep -Ev ${FILTER}`
 SYM=(${SYMS})
-GLOBALS="../libs/libc/modlib/modlib_globals.S"
+GLOBALS="libs/libc/modlib/modlib_globals.S"
 I_EP=0
 
 #
@@ -80,70 +93,100 @@ EP=(${EPS})
 #
 # Generate the modlib_xxxx_globals.S file
 #
-	GLOBALS="libs/libc/modlib/modlib_${arch}_globals.S"
 cat >${GLOBALS} <<__EOF__
+#ifdef __CYGWIN__
+#  define SYMBOL(s) _##s
+#  define WEAK .weak
+#  define GLOBAL .global
+#  define SECTION .data
+	.macro GLOBAL ep
+	.global	SYMBOL(\ep)
+	.type	SYMBOL(\ep), "object"
+	.endm
+	.macro SIZE ep
+	.endm
+#elif defined(__ELF__)
+#  define SYMBOL(s) s
+#  define WEAK .weak
+#  define SECTION .data
+	.macro GLOBAL ep
+	.global	SYMBOL(\ep)
+	.type	SYMBOL(\ep), "object"
+	.endm
+	.macro SIZE ep
+	.size	SYMBOL(\ep), . - SYMBOL(\ep)
+	.endm
+#else
+#  define SYMBOL(s) _##s
+#  define WEAK .weak_definition
+#  define SECTION .section __DATA,__data
+	.macro GLOBAL ep
+	.private_extern SYMBOL(\ep)
+	.globl 	SYMBOL(\ep)
+	.endm
+	.macro SIZE ep
+	.endm
+#endif
+
 #if __SIZEOF_POINTER__ == 8
 	.macro globalEntry index, ep
-	.weak  \p
+	WEAK	SYMBOL(\ep)
-	.quad  .L\index
+	.quad	.l\index
-	.quad  \ep
+	.quad	\ep
 	.endm
 # define ALIGN 8
 #else
 	.macro globalEntry index, ep
-	.weak  \ep		
+	WEAK	SYMBOL(\ep)		
-	.long  .L\index
+	.long	.l\index
-	.long  \ep
+	.long	\ep
 	.endm
 # define ALIGN 4
 #endif
 #ifdef __ARM_ARCH_ISA_THUMB2
 # ifdef __ARM_ARCH_7M__
-        .arch armv7e-m
+	.arch armv7e-m
 # elif defined ___ARM_ARCH 8
 	.arch armv8-m.base
 #endif
 #ifdef __ARM_ASM_SYNTAX_UNIFIED__
-        .syntax unified
+	.syntax	unified
 #endif
-        .thumb
+	.thumb
 #endif
-        .data
+	.data
-        .align ALIGN
+	.align	ALIGN
-	.global globalNames
+	GLOBAL	globalNames 
 
-globalNames:
+SYMBOL(globalNames):
 __EOF__
 
 for ((i = 0; i < ${#EP[@]}; i++))
 do
-	echo ".L${i}:	.string	\"${EP[$i]}\"" >>${GLOBALS}
+	echo ".l${i}:	.string	\"${EP[$i]}\"" >>${GLOBALS}
 done
 
 cat >>${GLOBALS} <<__EOF__
-	.size	globalNames, . - globalNames
+	SIZE	globalNames 
 
-	.align	${ALIGN}
+	.align	ALIGN
-	.global	nGlobals
+	GLOBAL	nGlobals
-	.type	nGlobals, "object"
+SYMBOL(nGlobals):	
-nGlobals:	
 	.word	${#EP[@]}
-	.size	nGlobals, . - nGlobals
+	SIZE	nGlobals
 
-	.align	${ALIGN}
+	.align	ALIGN
-	.global globalTable
+	GLOBAL	globalTable
-	.type	globalTable, "object"
+SYMBOL(globalTable):
-globalTable:
 __EOF__
 
 for ((i = 0; i < ${#EP[@]}; i++))
 do
-	echo "  globalEntry ${i}, ${EP[$i]}" >>${GLOBALS}
+	echo "	globalEntry ${i}, ${EP[$i]}" >>${GLOBALS}
 done
 
 cat >>${GLOBALS} <<__EOF__ 
-	.size	globalTable, . - globalTable
+	SIZE	globalTable
 __EOF__
 
-done
 echo "${#EP[@]} symbols defined"

libs/libc/machine/arm/armv7-m/arch_elf.c

@@ -493,14 +493,10 @@ int up_relocate(const Elf32_Rel *rel, const Elf32_Sym *sym, uintptr_t addr)
       }
       break;
 
-    case R_ARM_RELATIVE :
+    case R_ARM_RELATIVE:
-    case R_ARM_JUMP_SLOT :
+    case R_ARM_JUMP_SLOT:
       {
-        binfo("Relocating: RELATIVE/JUMP_SLOT at %p value: %08lx"
+        *(uint32_t *)addr = (uint32_t)sym->st_value;
-               "with %08lx\n",
-              (void *)addr, *(unsigned long *)addr,
-              (unsigned long)sym->st_value);
-        *(uint32_t *) addr = (uint32_t) sym->st_value;
       }
       break;
 

libs/libc/modlib/modlib_loadhdrs.c

@@ -70,14 +70,6 @@ int modlib_loadhdrs(FAR struct mod_loadinfo_s *loadinfo)
       return -EINVAL;
     }
 
-  /* Verify that there are program headers */
-
-  if (loadinfo->ehdr.e_phnum < 1)
-    {
-      berr("ERROR: No program headers(?)\n");
-      return -EINVAL;
-    }
-
   /* Get the total size of the section header table */
 
   shdrsize = (size_t)loadinfo->ehdr.e_shentsize *
@@ -88,19 +80,9 @@ int modlib_loadhdrs(FAR struct mod_loadinfo_s *loadinfo)
       return -ESPIPE;
     }
 
-  /* Get the total size of the program header table */
-
-  phdrsize = (size_t)loadinfo->ehdr.e_phentsize *
-             (size_t)loadinfo->ehdr.e_phnum;
-  if (loadinfo->ehdr.e_phoff + phdrsize > loadinfo->filelen)
-    {
-      berr("ERROR: Insufficent space in file for program header table\n");
-      return -ESPIPE;
-    }
-
   /* Allocate memory to hold a working copy of the sector header table */
 
-  loadinfo->shdr = (FAR FAR Elf_Shdr *)lib_malloc(shdrsize);
+  loadinfo->shdr = (FAR Elf_Shdr *)lib_malloc(shdrsize);
   if (!loadinfo->shdr)
     {
       berr("ERROR: Failed to allocate the section header table. Size: %ld\n",
@@ -117,26 +99,43 @@ int modlib_loadhdrs(FAR struct mod_loadinfo_s *loadinfo)
       berr("ERROR: Failed to read section header table: %d\n", ret);
     }
 
-  /* Allocate memory to hold a working copy of the program header table */
+  if (loadinfo->ehdr.e_phnum > 0)
-
-  loadinfo->phdr = (FAR FAR Elf_Phdr *)lib_malloc(phdrsize);
-  if (!loadinfo->shdr)
     {
-      lib_free((FAR void *)loadinfo->shdr);
+      /* Get the total size of the program header table */
-      berr("ERROR: Failed to allocate the program header table. Size: %ld\n",
+
-           (long)phdrsize);
+      phdrsize = (size_t)loadinfo->ehdr.e_phentsize *
-      return -ENOMEM;
+                 (size_t)loadinfo->ehdr.e_phnum;
+      if (loadinfo->ehdr.e_phoff + phdrsize > loadinfo->filelen)
+        {
+          berr("ERROR: Insufficent space for program header table\n");
+          return -ESPIPE;
+        }
+
+      /* Allocate memory to hold a working copy of the program header table */
+
+      loadinfo->phdr = (FAR Elf_Phdr *)lib_malloc(phdrsize);
+      if (!loadinfo->phdr)
+        {
+          lib_free((FAR void *)loadinfo->shdr);
+          berr("ERROR: Failed to allocate the program header table."
+               "Size: %ld\n", (long)phdrsize);
+          return -ENOMEM;
+        }
+
+      /* Read the program header table into memory */
+
+      ret = modlib_read(loadinfo, (FAR uint8_t *)loadinfo->phdr, phdrsize,
+                        loadinfo->ehdr.e_phoff);
+      if (ret < 0)
+        {
+          berr("ERROR: Failed to read program header table: %d\n", ret);
+          lib_free((FAR void *)loadinfo->phdr);
+          lib_free((FAR void *)loadinfo->shdr);
+        }
     }
-
+  else
-  /* Read the program header table into memory */
-
-  ret = modlib_read(loadinfo, (FAR uint8_t *)loadinfo->phdr, phdrsize,
-                    loadinfo->ehdr.e_phoff);
-  if (ret < 0)
     {
-      berr("ERROR: Failed to read program header table: %d\n", ret);
+      loadinfo->phdr = NULL;
-      lib_free((FAR void *)loadinfo->phdr);
-      lib_free((FAR void *)loadinfo->shdr);
     }
 
   return ret;

libs/libc/modlib/modlib_verify.c

@@ -80,11 +80,11 @@ int modlib_verifyheader(FAR const Elf_Ehdr *ehdr)
 
   if (ehdr->e_type != ET_REL)
     {
-        if (ehdr->e_type != ET_DYN)
+      if (ehdr->e_type != ET_DYN)
-          {
+        {
-            berr("ERROR: Not a relocatable file: e_type=%d\n", ehdr->e_type);
+          berr("ERROR: Not a relocatable file: e_type=%d\n", ehdr->e_type);
-            return -EINVAL;
+          return -EINVAL;
-          }
+        }
     }
 
   /* Verify that this file works with the currently configured architecture */