Teach elf2aif to handle EABI binaries

The previous attempt was bogus as elf2aif is built for the system
that the cross compiler runs on and thus __ARM_EABI__ would only
be set if the cross compiler was built for an ARM-based system.
Further, removing the OSABI check completely is fragile, so let's
not do that.

Instead, we introduce a new command line option for elf2aif which
must be specified if processing EABI binaries. This alters the
OSABI check to test for SysV, rather than ARM in the EABI case.

Additionally, correct functioning of ARMEABISupport is reliant on
the application loader to cause the ARMEABISupport abort handler
to be installed. For ELF binaries, this is ensured by SOManager.
For AIF binaries, however, RISC OS itself knows nothing about
ARMEABISupport and thus will not ensure that the abort handler
is installed. Make elf2aif inject the necessary SWI call into
_start (overwriting instructions that are meaningless when the
binary is not loaded by SOManager). This ensures that the abort
handler is installed as early in the application execution as
possible (and long before any memory managed by ARMEABISupport
is allocated).

2 files changed, 110 insertions, 16 deletions

diff --git a/arm-riscos-gnueabihf/recipes/patches/gccsdk/elf2aif-eabi-support.p b/arm-riscos-gnueabihf/recipes/patches/gccsdk/elf2aif-eabi-support.p
new file mode 100644
index 0000000..1d8b841
--- /dev/null
+++ b/arm-riscos-gnueabihf/recipes/patches/gccsdk/elf2aif-eabi-support.p
@@ -0,0 +1,110 @@
+Index: elf2aif/src/elf2aif.c
+===================================================================
+--- elf2aif/src/elf2aif.c	(revision 7698)
++++ elf2aif/src/elf2aif.c	(working copy)
+@@ -72,12 +72,13 @@
+ } aifheader_t;
+ 
+ static int opt_verbose = 0;
++static int opt_eabi = 0;
+ 
+ static Elf32_External_Ehdr elf_ehdr;
+ static phdr_list_t *elf_phdrlistP;
+ static const char *elf_filename;
+ 
+-static const unsigned int aifcode[] = {
++static const uint32_t aifcode[] = {
+   0xE1A00000,			/* NOP (BL decompress)      */
+   0xE1A00000,			/* NOP (BL self-relocate)   */
+   0xEB00000C,			/* BL zero-init             */
+@@ -113,6 +114,24 @@
+   0xEAFFFFFB			/* B     zeroloop           */
+ };
+ 
++static const uint32_t crt0code[] = {
++  0xE59F3010,			/* LDR   R3, =crt1_data     */
++  0xE583000C,			/* STR   R0, [R3, #12]      */
++  0xE583101C,			/* STR   R1, [R3, #28]      */
++  0xE5832020,			/* STR   R2, [R3, #32]      */
++  0xE1A00003			/* MOV   R0, R3             */
++ 				/* B     __main             */
++};
++
++static const uint32_t eabi_crt0code[] = {
++  0xE59F3010,			/* LDR   R3, =crt1_data     */
++  0xE583000C,			/* STR   R0, [R3, #12]      */
++  0xE3A00002,			/* MOV   R0, #2             */
++  0xEF059D01,			/* SWI   ARMEABISupport_AbortOp */
++  0xE1A00003			/* MOV   R0, R3             */
++  				/* B     __main             */
++};
++
+ /* Read a little-endian 'short' value.  */
+ static uint16_t
+ RdShort (const uint8_t sh[2])
+@@ -143,6 +162,7 @@
+   fprintf (stderr, "Usage: elf2aif [options] <ELF file> [<AIF file>]\n"
+ 	   "Convert static ARM ELF binary to AIF (Acorn Image Format) binary.\n"
+ 	   "Options:\n"
++	   "  -e, --eabi	source binary uses EABI\n"
+ 	   "  -v, --verbose	prints informational messages during processing\n"
+ 	   "      --help	display this help and exit\n"
+ 	   "      --version	output version information and exit\n");
+@@ -201,7 +221,8 @@
+       return EXIT_FAILURE;
+     }
+ 
+-  if (elf_ehdr.e_ident[EI_OSABI] != ELFOSABI_ARM)
++  if ((!opt_eabi && elf_ehdr.e_ident[EI_OSABI] != ELFOSABI_ARM) ||
++      (opt_eabi && elf_ehdr.e_ident[EI_OSABI] != ELFOSABI_NONE))
+     {
+       fprintf (stderr, "ELF file '%s' is not for ARM\n", elf_filename);
+       return EXIT_FAILURE;
+@@ -503,6 +524,37 @@
+       return EXIT_FAILURE;
+     }
+ 
++  /* In the EABI case we need to inject the code to install
++   * the ARMEABISupport abort handler */
++  if (opt_eabi)
++    {
++      uint32_t crt0[5];
++      assert(sizeof (crt0code) == sizeof (crt0));
++      assert(sizeof (eabi_crt0code) == sizeof (crt0));
++
++      if (opt_verbose)
++	printf ("Rewriting crt0 at offset 0x%x\n", (exec_addr - load_addr));
++
++      if (fseek (elfhandle, (exec_addr - load_addr), SEEK_SET) != 0 ||
++	  fread (crt0, sizeof (crt0), 1, elfhandle) != 1)
++	{
++	  fprintf (stderr, "Failed to read crt0\n");
++	  return EXIT_FAILURE;
++	}
++      if (memcmp(crt0, crt0code, sizeof (crt0)) != 0)
++	{
++	  fprintf (stderr, "crt0 code not as expected\n");
++	  return EXIT_FAILURE;
++	}
++      if (fseek (aifhandle, (exec_addr - load_addr), SEEK_SET) != 0 ||
++	  fwrite (eabi_crt0code, sizeof (crt0), 1, aifhandle) != 1 ||
++	  fseek (aifhandle, aifend, SEEK_SET) != 0)
++	{
++	  fprintf (stderr, "Failed to write crt0\n");
++	  return EXIT_FAILURE;
++	}
++    }
++
+   return EXIT_SUCCESS;
+ }
+ 
+@@ -683,6 +735,9 @@
+ 	    fprintf (stderr, "Warning: extra options/arguments ignored\n");
+ 	  return EXIT_SUCCESS;
+ 	}
++      else if (!strcmp (&argv[i][1], "-eabi")
++	       || !strcmp (&argv[i][1], "e"))
++	opt_eabi = 1;
+       else if (!strcmp (&argv[i][1], "-verbose")
+ 	       || !strcmp (&argv[i][1], "v"))
+ 	++opt_verbose;
diff --git a/arm-riscos-gnueabihf/recipes/patches/gccsdk/elf2aif-no-abi-check.p b/arm-riscos-gnueabihf/recipes/patches/gccsdk/elf2aif-no-abi-check.p
deleted file mode 100644
index 3ad6372..0000000
--- a/arm-riscos-gnueabihf/recipes/patches/gccsdk/elf2aif-no-abi-check.p
+++ /dev/null
@@ -1,16 +0,0 @@
-Index: elf2aif/src/elf2aif.c
-===================================================================
---- elf2aif/src/elf2aif.c	(revision 7698)
-+++ elf2aif/src/elf2aif.c	(working copy)
-@@ -201,7 +201,11 @@
-       return EXIT_FAILURE;
-     }
- 
-+#ifndef __ARM_EABI__
-   if (elf_ehdr.e_ident[EI_OSABI] != ELFOSABI_ARM)
-+#else
-+  if (elf_ehdr.e_ident[EI_OSABI] != ELFOSABI_NONE)
-+#endif
-     {
-       fprintf (stderr, "ELF file '%s' is not for ARM\n", elf_filename);
-       return EXIT_FAILURE;