The ELF loader is basically functional (needs more testing)

git-svn-id: http://svn.code.sf.net/p/nuttx/code/trunk@5265 42af7a65-404d-4744-a932-0658087f49c3

8 files changed, 44 insertions, 29 deletions

diff --git a/nuttx/ChangeLog b/nuttx/ChangeLog
index 7c4a5a8cd..a80e5009a 100644
--- a/nuttx/ChangeLog
+++ b/nuttx/ChangeLog
@@ -3522,3 +3522,5 @@
 	* configs/stm32f4discovery/elf and configs/stm32f4discovery/scripts/gnu-elf.ld
 	  Add a configuration for testing the ARM ELF loader.
 	* binfmt/libelf:  Can't use fstat(). NuttX does not yet support it.  Damn!
+	* binfmt/libelf:  The basic ELF module execution appears fully functional.
+
diff --git a/nuttx/arch/arm/src/armv7-m/up_elf.c b/nuttx/arch/arm/src/armv7-m/up_elf.c
index 5f77470fa..202c902b4 100644
--- a/nuttx/arch/arm/src/armv7-m/up_elf.c
+++ b/nuttx/arch/arm/src/armv7-m/up_elf.c
@@ -218,8 +218,8 @@ int arch_relocate(FAR const Elf32_Rel *rel, FAR const Elf32_Sym *sym,
          * The branch target is encoded in these bits:
          *
          *   S     = upper_insn[10]
-         *   imm10 = upper_insn[9:0]
-         *   imm11 = lower_insn[10:0]
+         *   imm10 = upper_insn[0:9]
+         *   imm11 = lower_insn[0:10]
          *   J1    = lower_insn[13]
          *   J2    = lower_insn[11]
          */
@@ -227,7 +227,7 @@ int arch_relocate(FAR const Elf32_Rel *rel, FAR const Elf32_Sym *sym,
         upper_insn = (uint32_t)(*(uint16_t*)addr);
         lower_insn = (uint32_t)(*(uint16_t*)(addr + 2));
 
-        bvdbg("Performing JUMP24 [%d] link at addr=%08lx [%04x %04x] to sym=%p st_value=%08lx\n",
+        bvdbg("Performing THM_JUMP24 [%d] link at addr=%08lx [%04x %04x] to sym=%p st_value=%08lx\n",
               ELF32_R_TYPE(rel->r_info), (long)addr, (int)upper_insn, (int)lower_insn,
               sym, (long)sym->st_value);
 
@@ -235,9 +235,9 @@ int arch_relocate(FAR const Elf32_Rel *rel, FAR const Elf32_Sym *sym,
          *
          *   offset[24]    = S
          *   offset[23]    = ~(J1 ^ S)
-         *   offset[22     = ~(J2 ^ S)]
-         *   offset[21:12] = imm10
-         *   offset[11:1]  = imm11
+         *   offset[22]    = ~(J2 ^ S)]
+         *   offset[12:21] = imm10
+         *   offset[1:11]  = imm11
          *   offset[0]     = 0
          */
 
@@ -245,11 +245,12 @@ int arch_relocate(FAR const Elf32_Rel *rel, FAR const Elf32_Sym *sym,
         J1  = (lower_insn >> 13) & 1;
         J2  = (lower_insn >> 11) & 1;
 
-        offset = (S << 24) |
-                 ((~(J1 ^ S) & 1) << 23) |
-                 ((~(J2 ^ S) & 1) << 22) |
-                 ((upper_insn & 0x03ff) << 12) |
-                 ((lower_insn & 0x07ff) << 1);
+        offset = (S << 24) |                       /* S -   > offset[24] */
+                 ((~(J1 ^ S) & 1) << 23) |         /* J1    -> offset[23] */
+                 ((~(J2 ^ S) & 1) << 22) |         /* J2    -> offset[22] */
+                 ((upper_insn & 0x03ff) << 12) |   /* imm10 -> offset[12:21] */
+                 ((lower_insn & 0x07ff) << 1);     /* imm11 -> offset[1:11] */
+                                                   /* 0     -> offset[0] */
 
         /* Sign extend */
 
@@ -374,31 +375,31 @@ int arch_relocate(FAR const Elf32_Rel *rel, FAR const Elf32_Sym *sym,
          *  5   4   3   2   1   0   9   8   7   6   5   4   3   2   1   0
          * +---+---------------------------------------------------------+
          * |OP |                                                         | 32-Bit Instructions
-         * +---+--+-------+--------------+-------------------------------+
-         * |0  |1 | imm3  |      Rd      |            imm8               | MOVT Instruction
-         * +---+--+-------+--------------+-------------------------------+
+         * +---+----------+--------------+-------------------------------+
+         * |0  |   imm3   |      Rd      |            imm8               | MOVT Instruction
+         * +---+----------+--------------+-------------------------------+
          *
          * The 16-bit immediate value is encoded in these bits:
          *
          *   i    = imm16[11]    = upper_insn[10]
          *   imm4 = imm16[12:15] = upper_insn[3:0]
-         *   imm3 = imm16[9:11]  = lower_insn[14:12]
-         *   imm8 = imm16[0:8]   = lower_insn[7:0]
+         *   imm3 = imm16[8:10]  = lower_insn[14:12]
+         *   imm8 = imm16[0:7]   = lower_insn[7:0]
          */
 
         upper_insn = (uint32_t)(*(uint16_t*)addr);
         lower_insn = (uint32_t)(*(uint16_t*)(addr + 2));
 
-        bvdbg("Performing MOVx [%d] link at addr=%08lx [%04x %04x] to sym=%p st_value=%08lx\n",
+        bvdbg("Performing THM_MOVx [%d] link at addr=%08lx [%04x %04x] to sym=%p st_value=%08lx\n",
               ELF32_R_TYPE(rel->r_info), (long)addr, (int)upper_insn, (int)lower_insn,
               sym, (long)sym->st_value);
 
         /* Extract the 16-bit offset from the 32-bit instruction */
 
-        offset = ((upper_insn & 0x000f) << 12) |
-                 ((upper_insn & 0x0400) << 1) |
-                 ((lower_insn & 0x7000) >> 4) |
-                  (lower_insn & 0x00ff);
+        offset = ((upper_insn & 0x000f) << 12) | /* imm4 -> imm16[8:10] */
+                 ((upper_insn & 0x0400) << 1) |  /* i    -> imm16[11] */
+                 ((lower_insn & 0x7000) >> 4) |  /* imm3 -> imm16[8:10] */
+                  (lower_insn & 0x00ff);         /* imm8 -> imm16[0:7] */
 
         /* Sign extend */
 
@@ -406,8 +407,8 @@ int arch_relocate(FAR const Elf32_Rel *rel, FAR const Elf32_Sym *sym,
 
         /* And perform the relocation */
 
-        bvdbg("  S=%d J1=%d J2=%d offset=%08lx branch target=%08lx\n",
-              S, J1, J2, (long)offset, offset + sym->st_value);
+        bvdbg("  offset=%08lx branch target=%08lx\n",
+              (long)offset, offset + sym->st_value);
 
         offset += sym->st_value;
 
diff --git a/nuttx/arch/arm/src/stm32/Kconfig b/nuttx/arch/arm/src/stm32/Kconfig
index 5fd0ae7a2..acfac81aa 100644
--- a/nuttx/arch/arm/src/stm32/Kconfig
+++ b/nuttx/arch/arm/src/stm32/Kconfig
@@ -636,9 +636,11 @@ config ARCH_BOARD_STM32_CUSTOM_CLOCKCONFIG
 config STM32_CCMEXCLUDE
 	bool "Exclude CCM SRAM from the heap"
 	depends on STM32_STM32F20XX || STM32_STM32F40XX
-	default y if  ARCH_DMA
+	default y if  ARCH_DMA || ELF
 	---help---
-		Exclude CCM SRAM from the HEAP because it cannot be used for DMA.
+		Exclude CCM SRAM from the HEAP because (1) it cannot be used for DMA
+		and (2) it appears to be impossible to execute ELF modules from CCM
+		RAM.
 
 config STM32_FSMC_SRAM
 	bool "External SRAM on FSMC"
diff --git a/nuttx/binfmt/libelf/libelf_bind.c b/nuttx/binfmt/libelf/libelf_bind.c
index f41b5a0b6..54ea8f1f0 100644
--- a/nuttx/binfmt/libelf/libelf_bind.c
+++ b/nuttx/binfmt/libelf/libelf_bind.c
@@ -142,7 +142,10 @@ static int elf_relocate(FAR struct elf_loadinfo_s *loadinfo, int relidx,
   int             ret;
   int             i;
 
-  /* Examine each relocation in the section */
+  /* Examine each relocation in the section.  'relsec' is the section
+   * containing the relations.  'dstsec' is the section containing the data
+   * to be relocated.
+   */
 
   for (i = 0; i < relsec->sh_size / sizeof(Elf32_Rel); i++)
     {
diff --git a/nuttx/binfmt/libelf/libelf_init.c b/nuttx/binfmt/libelf/libelf_init.c
index e1b9f73d6..fa4b7983c 100644
--- a/nuttx/binfmt/libelf/libelf_init.c
+++ b/nuttx/binfmt/libelf/libelf_init.c
@@ -154,6 +154,7 @@ int elf_init(FAR const char *filename, FAR struct elf_loadinfo_s *loadinfo)
   /* Get the length of the file. */
 
   ret = elf_filelen(loadinfo, filename);
+  if (ret < 0)
     {
       bdbg("elf_filelen failed: %d\n", ret);
       return ret;
diff --git a/nuttx/configs/stm32f4discovery/README.txt b/nuttx/configs/stm32f4discovery/README.txt
index d1a55daa9..e8f0ae166 100644
--- a/nuttx/configs/stm32f4discovery/README.txt
+++ b/nuttx/configs/stm32f4discovery/README.txt
@@ -1007,6 +1007,10 @@ Where <subdir> is one of the following:
     3. By default, this project assumes that you are *NOT* using the DFU
        bootloader.
  
+    4. This configuration requires that you have the genromfs tool installed
+       on your system and that you have the full path to the installed genromfs
+       executable in PATH variable (see apps/examples/README.txt)
+
   ostest:
   ------
     This configuration directory, performs a simple OS test using
diff --git a/nuttx/configs/stm32f4discovery/elf/Make.defs b/nuttx/configs/stm32f4discovery/elf/Make.defs
index 7f5be08f0..c64102d17 100644
--- a/nuttx/configs/stm32f4discovery/elf/Make.defs
+++ b/nuttx/configs/stm32f4discovery/elf/Make.defs
@@ -160,6 +160,7 @@ LDNXFLATFLAGS = -e main -s 2048
 
 # ELF module definitions
 
+CELFFLAGS = $(CFLAGS) -mlong-calls
 LDELFFLAGS = -r -e main
 ifeq ($(WINTOOL),y)
   LDELFFLAGS += -T "${shell cygpath -w $(TOPDIR)/configs/$(CONFIG_ARCH_BOARD)/scripts/gnu-elf.ld}"
diff --git a/nuttx/configs/stm32f4discovery/elf/defconfig b/nuttx/configs/stm32f4discovery/elf/defconfig
index dd5bd2829..6d72e4a9e 100644
--- a/nuttx/configs/stm32f4discovery/elf/defconfig
+++ b/nuttx/configs/stm32f4discovery/elf/defconfig
@@ -179,7 +179,7 @@ CONFIG_STM32_USART2=y
 CONFIG_STM32_JTAG_SW_ENABLE=y
 # CONFIG_STM32_FORCEPOWER is not set
 # CONFIG_ARCH_BOARD_STM32_CUSTOM_CLOCKCONFIG is not set
-# CONFIG_STM32_CCMEXCLUDE is not set
+CONFIG_STM32_CCMEXCLUDE=y
 
 #
 # USB Host Configuration
@@ -251,7 +251,7 @@ CONFIG_SDCLONE_DISABLE=y
 # CONFIG_SCHED_WAITPID is not set
 # CONFIG_SCHED_ATEXIT is not set
 # CONFIG_SCHED_ONEXIT is not set
-CONFIG_USER_ENTRYPOINT="ostest_main"
+CONFIG_USER_ENTRYPOINT="elf_main"
 CONFIG_DISABLE_OS_API=y
 # CONFIG_DISABLE_CLOCK is not set
 # CONFIG_DISABLE_POSIX_TIMERS is not set
@@ -387,6 +387,7 @@ CONFIG_ELF_ALIGN_LOG2=2
 CONFIG_ELF_STACKSIZE=2048
 CONFIG_ELF_BUFFERSIZE=128
 CONFIG_ELF_BUFFERINCR=32
+# CONFIG_ELF_CONSTRUCTORS is not set
 CONFIG_SYMTAB_ORDEREDBYNAME=y
 
 #
@@ -409,7 +410,7 @@ CONFIG_ARCH_LOWPUTC=y
 CONFIG_LIB_SENDFILE_BUFSIZE=512
 # CONFIG_ARCH_ROMGETC is not set
 # CONFIG_ARCH_OPTIMIZED_FUNCTIONS is not set
-# CONFIG_HAVE_CXX is not set
+CONFIG_HAVE_CXX=y
 # CONFIG_HAVE_CXXINITIALIZE is not set
 # CONFIG_CXX_NEWLONG is not set