Steven J. Hill's latest mips dynamic loader updates

8 files changed, 294 insertions, 52 deletions

diff --git a/ldso/ldso/mips/README b/ldso/ldso/mips/README
new file mode 100644
index 000000000..b54e25183
--- /dev/null
+++ b/ldso/ldso/mips/README
@@ -0,0 +1,43 @@
+Almost all of the code present in these source files was taken
+from GLIBC. In the descriptions below, all files mentioned are
+with respect to the top level GLIBC source directory accept for
+the code taken from the Linux kernel.
+
+boot1_arch.h
+------------
+Contains code to fix up the stack pointer so that the dynamic
+linker can find argc, argv and Auxillary Vector Table (AVT).
+The codes is taken from the function 'RTLD_START' in the
+file 'sysdeps/mips/dl-machine.h'.
+
+elfinterp.c
+-----------
+Contains '_dl_init_got' which initializes the GOT for the
+application being dynamically linked and loaded. The code is
+taken from the functions 'elf_machine_runtime_setup' and 
+'elf_machine_got_rel' in the file 'sysdeps/mips/dl-machine.h'.
+
+ld_syscalls.h
+-------------
+Contains all the macro function prototypes for the system calls
+as well as the list of system calls supported. The macros were
+taken from the Linux kernel source 2.4.17 found in the file
+'include/asm-mips/unistd.h'.
+
+ld_sysdep.h
+-----------
+Contains bootstrap code for the dynamic linker, magic numbers
+for detecting MIPS target types and some macros. The macro
+function 'PERFORM_BOOTSTRAP_GOT' is used to relocate the dynamic
+linker's GOT so that function calls can be made. The code is
+taken from the function 'ELF_MACHINE_BEFORE_RTLD_RELOC' in the
+file 'sysdep/mips/dl-machine.h'. The other macro function
+'PERFORM_BOOTSTRAP_RELOC' is used to do the relocations for
+the dynamic loader. The code is taken from the function
+'elf_machine_rel' in the file 'sysdep/mips/dl-machine.h'.
+
+resolve.S
+---------
+Contains the low-level assembly code for the dynamic runtime
+resolver. The code is taken from the assembly code function
+'_dl_runtime_resolve' in the file 'sysdesp/mips/dl-machine.h'.
diff --git a/ldso/ldso/mips/boot1_arch.h b/ldso/ldso/mips/boot1_arch.h
index e86ff77cf..f439ee4bc 100644
--- a/ldso/ldso/mips/boot1_arch.h
+++ b/ldso/ldso/mips/boot1_arch.h
@@ -13,11 +13,8 @@ _dl_boot:
 	nop
 0:	.cpload $31
 	.set reorder
-	# i386 ABI book says that the first entry of GOT holds
-	# the address of the dynamic structure. Though MIPS ABI
-	# doesn't say nothing about this, I emulate this here.
+	# Store offset of DYNAMIC section in first entry of GOT
 	la $4, _DYNAMIC
-	# Subtract OFFSET_GP_GOT
 	sw $4, -0x7ff0($28)
 	move $4, $29
 	la $8, coff
diff --git a/ldso/ldso/mips/dl-startup.h b/ldso/ldso/mips/dl-startup.h
index e86ff77cf..f439ee4bc 100644
--- a/ldso/ldso/mips/dl-startup.h
+++ b/ldso/ldso/mips/dl-startup.h
@@ -13,11 +13,8 @@ _dl_boot:
 	nop
 0:	.cpload $31
 	.set reorder
-	# i386 ABI book says that the first entry of GOT holds
-	# the address of the dynamic structure. Though MIPS ABI
-	# doesn't say nothing about this, I emulate this here.
+	# Store offset of DYNAMIC section in first entry of GOT
 	la $4, _DYNAMIC
-	# Subtract OFFSET_GP_GOT
 	sw $4, -0x7ff0($28)
 	move $4, $29
 	la $8, coff
diff --git a/ldso/ldso/mips/dl-syscalls.h b/ldso/ldso/mips/dl-syscalls.h
index feb54d4cf..da17d63b9 100644
--- a/ldso/ldso/mips/dl-syscalls.h
+++ b/ldso/ldso/mips/dl-syscalls.h
@@ -142,4 +142,34 @@ type name(atype a, btype b, ctype c, dtype d) \
 	return (type) -1; \
 }
 
+#define _syscall6(type,name,atype,a,btype,b,ctype,c,dtype,d,etype,e,ftype,f) \
+type name(atype a, btype b, ctype c, dtype d, etype e, ftype f) \
+{ \
+	register unsigned long __v0 asm("$2") = __NR_##name; \
+	register unsigned long __a0 asm("$4") = (unsigned long) a; \
+	register unsigned long __a1 asm("$5") = (unsigned long) b; \
+	register unsigned long __a2 asm("$6") = (unsigned long) c; \
+	register unsigned long __a3 asm("$7") = (unsigned long) d; \
+	\
+	__asm__ volatile ( \
+	".set\tnoreorder\n\t" \
+	"lw\t$2, %6\n\t" \
+	"lw\t$8, %7\n\t" \
+	"subu\t$29, 32\n\t" \
+	"sw\t$2, 16($29)\n\t" \
+	"sw\t$8, 20($29)\n\t" \
+	"li\t$2, %5\t\t\t# " #name "\n\t" \
+	"syscall\n\t" \
+	"addiu\t$29, 32\n\t" \
+	".set\treorder" \
+	: "=&r" (__v0), "+r" (__a3) \
+	: "r" (__a0), "r" (__a1), "r" (__a2), "i" (__NR_##name), \
+	  "m" ((unsigned long)e), "m" ((unsigned long)f) \
+	: "$8", "$9", "$10", "$11", "$12", "$13", "$14", "$15", "$24"); \
+	\
+	if (__a3 == 0) \
+		return (type) __v0; \
+	return (type) -1; \
+}
+
 #endif
diff --git a/ldso/ldso/mips/dl-sysdep.h b/ldso/ldso/mips/dl-sysdep.h
index 24cbc3d04..8bc6aaccd 100644
--- a/ldso/ldso/mips/dl-sysdep.h
+++ b/ldso/ldso/mips/dl-sysdep.h
@@ -8,36 +8,82 @@
  */
 #undef ELF_USES_RELOCA
 
+
 /*
  * Get a pointer to the argv array.  On many platforms this can be just
  * the address if the first argument, on other platforms we need to
  * do something a little more subtle here.
  */
-#define GET_ARGV(ARGVP, ARGS) ARGVP = ((unsigned long*)   ARGS)
+#define GET_ARGV(ARGVP, ARGS) ARGVP = ((unsigned long *) ARGS)
+
 
 /*
- * Initialization sequence for a GOT.
+ * Initialization sequence for the application GOT.
  */
-#define INIT_GOT(GOT_BASE,MODULE) \
-{				\
-  GOT_BASE[0] = (unsigned long) _dl_linux_resolve; \
-  GOT_BASE[1] = (unsigned long) MODULE; \
-}
+#define INIT_GOT(GOT_BASE,MODULE)	_dl_init_got(GOT_BASE,MODULE)
+
+
+/*
+ * Here is a macro to perform the GOT relocation.  This is only
+ * used when bootstrapping the dynamic loader.
+ */
+#define PERFORM_BOOTSTRAP_GOT(got)					\
+do {									\
+	Elf32_Sym *sym;							\
+	unsigned long i;						\
+									\
+	/* Add load address displacement to all local GOT entries */	\
+	i = 2;								\
+	while (i < mips_local_gotno)					\
+		got[i++] += load_addr;					\
+									\
+	/* Handle global GOT entries */					\
+	got += mips_local_gotno;					\
+	sym = (Elf32_Sym *) (tpnt->dynamic_info[DT_SYMTAB] +		\
+		 load_addr) + mips_gotsym;				\
+	i = mips_symtabno - mips_gotsym;				\
+									\
+	while (i--) {							\
+		if (sym->st_shndx == SHN_UNDEF ||			\
+			sym->st_shndx == SHN_COMMON)			\
+			*got = load_addr + sym->st_value;		\
+		else if (ELF32_ST_TYPE(sym->st_info) == STT_FUNC &&	\
+			*got != sym->st_value)				\
+			*got += load_addr;				\
+		else if (ELF32_ST_TYPE(sym->st_info) == STT_SECTION) {	\
+			if (sym->st_other == 0)				\
+				*got += load_addr;			\
+		}							\
+		else							\
+			*got = load_addr + sym->st_value;		\
+									\
+		got++;							\
+		sym++;							\
+	}								\
+} while (0)
+
 
 /*
  * Here is a macro to perform a relocation.  This is only used when
- * bootstrapping the dynamic loader.  RELP is the relocation that we
- * are performing, REL is the pointer to the address we are relocating.
- * SYMBOL is the symbol involved in the relocation, and LOAD is the
- * load address.
- *
- * !!!NOTE!!!
- *
- * For MIPS, we don't have any DT_JMPREL or DT_PLTRELSZ dynamic
- * entries, so this macro function is empty. The code contained
- * in elfinterp.c does the real relocation work.
+ * bootstrapping the dynamic loader.
  */
-#define PERFORM_BOOTSTRAP_RELOC(RELP,REL,SYMBOL,LOAD)
+#define PERFORM_BOOTSTRAP_RELOC(RELP,REL,SYMBOL,LOAD)			\
+	switch(ELF32_R_TYPE((RELP)->r_info)) {				\
+	case R_MIPS_REL32:						\
+		if (symtab_index) {					\
+			if (symtab_index < mips_gotsym)			\
+				*REL += SYMBOL + LOAD;			\
+		}							\
+		else {							\
+			*REL += LOAD;					\
+		}							\
+		break;							\
+	case R_MIPS_NONE:						\
+		break;							\
+	default:							\
+		SEND_STDERR("Aiieeee!");				\
+		_dl_exit(1);						\
+	}
 
 
 /*
@@ -45,19 +91,21 @@
  * is done.  This routine has to exit the current function, then 
  * call the _dl_elf_main function.
  */
-
 #define START()   return (void) _dl_elf_main;      
 
 
-
 /* Here we define the magic numbers that this dynamic loader should accept */
-
 #define MAGIC1 EM_MIPS
 #define MAGIC2 EM_MIPS_RS3_LE
+
+
 /* Used for error messages */
 #define ELF_TARGET "MIPS"
 
+
 struct elf_resolve;
-unsigned long _dl_linux_resolver(struct elf_resolve * tpnt, int reloc_entry);
+extern unsigned long _dl_linux_resolver(struct elf_resolve * tpnt,
+	int reloc_entry);
+void _dl_init_got(unsigned long *got, struct elf_resolve *tpnt);
 
 #define do_rem(result, n, base)  result = (n % base)
diff --git a/ldso/ldso/mips/elfinterp.c b/ldso/ldso/mips/elfinterp.c
new file mode 100644
index 000000000..c38a7ffa2
--- /dev/null
+++ b/ldso/ldso/mips/elfinterp.c
@@ -0,0 +1,49 @@
+/* Run an ELF binary on a linux system.
+
+   Copyright (C) 1993, Eric Youngdale.
+   Copyright (C) 2002, Steven J. Hill (sjhill@realitydiluted.com)
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 2, or (at your option)
+   any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.  */
+
+
+/* Program to load an ELF binary on a linux system, and run it.
+   References to symbols in sharable libraries can be resolved by either
+   an ELF sharable library or a linux style of shared library. */
+
+/* Disclaimer:  I have never seen any AT&T source code for SVr4, nor have
+   I ever taken any courses on internals.  This program was developed using
+   information available through the book "UNIX SYSTEM V RELEASE 4,
+   Programmers guide: Ansi C and Programming Support Tools", which did
+   a more than adequate job of explaining everything required to get this
+   working. */
+
+
+extern int _dl_linux_resolve(void);
+
+void _dl_init_got(unsigned long *got, struct elf_resolve *tpnt)
+{
+	return;
+}
+
+unsigned long _dl_linux_resolver(struct elf_resolve *tpnt, int reloc_entry)
+{
+	return 0;
+}
+
+int _dl_parse_relocation_information(struct elf_resolve *tpnt, 
+	unsigned long rel_addr, unsigned long rel_size, int type)
+{
+	return 1;
+}
diff --git a/ldso/ldso/mips/ld_syscalls.h b/ldso/ldso/mips/ld_syscalls.h
index feb54d4cf..da17d63b9 100644
--- a/ldso/ldso/mips/ld_syscalls.h
+++ b/ldso/ldso/mips/ld_syscalls.h
@@ -142,4 +142,34 @@ type name(atype a, btype b, ctype c, dtype d) \
 	return (type) -1; \
 }
 
+#define _syscall6(type,name,atype,a,btype,b,ctype,c,dtype,d,etype,e,ftype,f) \
+type name(atype a, btype b, ctype c, dtype d, etype e, ftype f) \
+{ \
+	register unsigned long __v0 asm("$2") = __NR_##name; \
+	register unsigned long __a0 asm("$4") = (unsigned long) a; \
+	register unsigned long __a1 asm("$5") = (unsigned long) b; \
+	register unsigned long __a2 asm("$6") = (unsigned long) c; \
+	register unsigned long __a3 asm("$7") = (unsigned long) d; \
+	\
+	__asm__ volatile ( \
+	".set\tnoreorder\n\t" \
+	"lw\t$2, %6\n\t" \
+	"lw\t$8, %7\n\t" \
+	"subu\t$29, 32\n\t" \
+	"sw\t$2, 16($29)\n\t" \
+	"sw\t$8, 20($29)\n\t" \
+	"li\t$2, %5\t\t\t# " #name "\n\t" \
+	"syscall\n\t" \
+	"addiu\t$29, 32\n\t" \
+	".set\treorder" \
+	: "=&r" (__v0), "+r" (__a3) \
+	: "r" (__a0), "r" (__a1), "r" (__a2), "i" (__NR_##name), \
+	  "m" ((unsigned long)e), "m" ((unsigned long)f) \
+	: "$8", "$9", "$10", "$11", "$12", "$13", "$14", "$15", "$24"); \
+	\
+	if (__a3 == 0) \
+		return (type) __v0; \
+	return (type) -1; \
+}
+
 #endif
diff --git a/ldso/ldso/mips/ld_sysdep.h b/ldso/ldso/mips/ld_sysdep.h
index 24cbc3d04..8bc6aaccd 100644
--- a/ldso/ldso/mips/ld_sysdep.h
+++ b/ldso/ldso/mips/ld_sysdep.h
@@ -8,36 +8,82 @@
  */
 #undef ELF_USES_RELOCA
 
+
 /*
  * Get a pointer to the argv array.  On many platforms this can be just
  * the address if the first argument, on other platforms we need to
  * do something a little more subtle here.
  */
-#define GET_ARGV(ARGVP, ARGS) ARGVP = ((unsigned long*)   ARGS)
+#define GET_ARGV(ARGVP, ARGS) ARGVP = ((unsigned long *) ARGS)
+
 
 /*
- * Initialization sequence for a GOT.
+ * Initialization sequence for the application GOT.
  */
-#define INIT_GOT(GOT_BASE,MODULE) \
-{				\
-  GOT_BASE[0] = (unsigned long) _dl_linux_resolve; \
-  GOT_BASE[1] = (unsigned long) MODULE; \
-}
+#define INIT_GOT(GOT_BASE,MODULE)	_dl_init_got(GOT_BASE,MODULE)
+
+
+/*
+ * Here is a macro to perform the GOT relocation.  This is only
+ * used when bootstrapping the dynamic loader.
+ */
+#define PERFORM_BOOTSTRAP_GOT(got)					\
+do {									\
+	Elf32_Sym *sym;							\
+	unsigned long i;						\
+									\
+	/* Add load address displacement to all local GOT entries */	\
+	i = 2;								\
+	while (i < mips_local_gotno)					\
+		got[i++] += load_addr;					\
+									\
+	/* Handle global GOT entries */					\
+	got += mips_local_gotno;					\
+	sym = (Elf32_Sym *) (tpnt->dynamic_info[DT_SYMTAB] +		\
+		 load_addr) + mips_gotsym;				\
+	i = mips_symtabno - mips_gotsym;				\
+									\
+	while (i--) {							\
+		if (sym->st_shndx == SHN_UNDEF ||			\
+			sym->st_shndx == SHN_COMMON)			\
+			*got = load_addr + sym->st_value;		\
+		else if (ELF32_ST_TYPE(sym->st_info) == STT_FUNC &&	\
+			*got != sym->st_value)				\
+			*got += load_addr;				\
+		else if (ELF32_ST_TYPE(sym->st_info) == STT_SECTION) {	\
+			if (sym->st_other == 0)				\
+				*got += load_addr;			\
+		}							\
+		else							\
+			*got = load_addr + sym->st_value;		\
+									\
+		got++;							\
+		sym++;							\
+	}								\
+} while (0)
+
 
 /*
  * Here is a macro to perform a relocation.  This is only used when
- * bootstrapping the dynamic loader.  RELP is the relocation that we
- * are performing, REL is the pointer to the address we are relocating.
- * SYMBOL is the symbol involved in the relocation, and LOAD is the
- * load address.
- *
- * !!!NOTE!!!
- *
- * For MIPS, we don't have any DT_JMPREL or DT_PLTRELSZ dynamic
- * entries, so this macro function is empty. The code contained
- * in elfinterp.c does the real relocation work.
+ * bootstrapping the dynamic loader.
  */
-#define PERFORM_BOOTSTRAP_RELOC(RELP,REL,SYMBOL,LOAD)
+#define PERFORM_BOOTSTRAP_RELOC(RELP,REL,SYMBOL,LOAD)			\
+	switch(ELF32_R_TYPE((RELP)->r_info)) {				\
+	case R_MIPS_REL32:						\
+		if (symtab_index) {					\
+			if (symtab_index < mips_gotsym)			\
+				*REL += SYMBOL + LOAD;			\
+		}							\
+		else {							\
+			*REL += LOAD;					\
+		}							\
+		break;							\
+	case R_MIPS_NONE:						\
+		break;							\
+	default:							\
+		SEND_STDERR("Aiieeee!");				\
+		_dl_exit(1);						\
+	}
 
 
 /*
@@ -45,19 +91,21 @@
  * is done.  This routine has to exit the current function, then 
  * call the _dl_elf_main function.
  */
-
 #define START()   return (void) _dl_elf_main;      
 
 
-
 /* Here we define the magic numbers that this dynamic loader should accept */
-
 #define MAGIC1 EM_MIPS
 #define MAGIC2 EM_MIPS_RS3_LE
+
+
 /* Used for error messages */
 #define ELF_TARGET "MIPS"
 
+
 struct elf_resolve;
-unsigned long _dl_linux_resolver(struct elf_resolve * tpnt, int reloc_entry);
+extern unsigned long _dl_linux_resolver(struct elf_resolve * tpnt,
+	int reloc_entry);
+void _dl_init_got(unsigned long *got, struct elf_resolve *tpnt);
 
 #define do_rem(result, n, base)  result = (n % base)