Port kallsyms to Xen, as 'symbols'.

Signed-off-by: Keir Fraser <keir@xensource.com>

12 files changed, 982 insertions, 52 deletions

diff --git a/.hgignore b/.hgignore
index 8d34b91699..2024edc1f0 100644
--- a/.hgignore
+++ b/.hgignore
@@ -162,10 +162,6 @@
 ^xen/arch/x86/asm-offsets\.s$
 ^xen/arch/x86/boot/mkelf32$
 ^xen/ddb/.*$
-^xen/drivers/pci/classlist\.h$
-^xen/drivers/pci/devlist\.h$
-^xen/drivers/pci/gen-devlist$
-^xen/figlet/figlet$
 ^xen/include/asm$
 ^xen/include/asm-.*/asm-offsets\.h$
 ^xen/include/hypervisor-ifs/arch$
@@ -175,8 +171,8 @@
 ^xen/include/xen/banner\.h$
 ^xen/include/xen/compile\.h$
 ^xen/tags$
-^xen/tools/elf-reloc$
 ^xen/tools/figlet/figlet$
+^xen/tools/symbols$
 ^xen/xen$
 ^xen/xen-syms$
 ^xen/xen\..*$
diff --git a/xen/Makefile b/xen/Makefile
index 6a2d9c3514..6ff01d0d30 100644
--- a/xen/Makefile
+++ b/xen/Makefile
@@ -50,10 +50,10 @@ clean: delete-unfresh-files
 	$(MAKE) -C arch/$(TARGET_ARCH) clean
 	rm -f include/asm *.o $(TARGET)* *~ core
 	rm -f include/asm-*/asm-offsets.h
-	rm -f tools/figlet/*.o tools/figlet/figlet
 	rm -f include/xen/acm_policy.h
 
 $(TARGET): delete-unfresh-files
+	$(MAKE) -C tools
 	$(MAKE) include/xen/compile.h
 	$(MAKE) include/xen/acm_policy.h
 	[ -e include/asm ] || ln -sf asm-$(TARGET_ARCH) include/asm
@@ -71,7 +71,6 @@ endif
 delete-unfresh-files:
 	@if [ ! -r include/xen/compile.h -o -O include/xen/compile.h ]; then \
 		rm -f include/xen/{banner,compile}.h; \
-		$(MAKE) -C arch/$(TARGET_ARCH) delete-unfresh-files; \
 	fi
 
 # acm_policy.h contains security policy for Xen
@@ -105,12 +104,7 @@ include/xen/compile.h: include/xen/compile.h.in include/xen/banner.h
 	@cat include/xen/banner.h >> $@.new
 	@mv -f $@.new $@
 
-tools/figlet/figlet: tools/figlet/figlet.o
-	$(HOSTCC) -o $@ $<
-tools/figlet/figlet.o: tools/figlet/figlet.c
-	$(HOSTCC) -o $@ -c $<
-
-include/xen/banner.h: tools/figlet/figlet tools/figlet/xen.flf
+include/xen/banner.h:
 	tools/figlet/figlet -d tools/figlet Xen $(XEN_FULLVERSION) > $@.new
 	@mv -f $@.new $@
 
diff --git a/xen/arch/ia64/Makefile b/xen/arch/ia64/Makefile
index 5e497818cc..5e52b47e3c 100644
--- a/xen/arch/ia64/Makefile
+++ b/xen/arch/ia64/Makefile
@@ -62,10 +62,4 @@ clean:
 	rm -f *.o *~ core  xen.lds.s $(BASEDIR)/include/asm-ia64/.offsets.h.stamp asm-offsets.s
 	rm -f lib/*.o
 
-# setup.o contains bits of compile.h so it must be blown away
-delete-unfresh-files:
-	echo any unfresh-files to delete for ia64\?
-#	rm -f setup.o
-
-.PHONY: default clean delete-unfresh-files
-
+.PHONY: default clean
diff --git a/xen/arch/x86/Makefile b/xen/arch/x86/Makefile
index 8291f00f3d..fe8b79c493 100644
--- a/xen/arch/x86/Makefile
+++ b/xen/arch/x86/Makefile
@@ -37,6 +37,15 @@ $(CURDIR)/arch.o: $(OBJS)
 $(TARGET)-syms: boot/$(TARGET_SUBARCH).o $(ALL_OBJS) $(TARGET_SUBARCH)/xen.lds
 	$(LD) $(LDFLAGS) -T $(TARGET_SUBARCH)/xen.lds -N \
 	    boot/$(TARGET_SUBARCH).o $(ALL_OBJS) -o $@
+	nm -n $@ | $(BASEDIR)/tools/symbols >$(BASEDIR)/xen-syms.S
+	$(MAKE) $(BASEDIR)/xen-syms.o
+	$(LD) $(LDFLAGS) -T $(TARGET_SUBARCH)/xen.lds -N \
+	    boot/$(TARGET_SUBARCH).o $(ALL_OBJS) $(BASEDIR)/xen-syms.o -o $@
+	nm -n $@ | $(BASEDIR)/tools/symbols >$(BASEDIR)/xen-syms.S
+	$(MAKE) $(BASEDIR)/xen-syms.o
+	$(LD) $(LDFLAGS) -T $(TARGET_SUBARCH)/xen.lds -N \
+	    boot/$(TARGET_SUBARCH).o $(ALL_OBJS) $(BASEDIR)/xen-syms.o -o $@
+	rm -f $(BASEDIR)/xen-syms.S $(BASEDIR)/xen-syms.o
 
 asm-offsets.s: $(TARGET_SUBARCH)/asm-offsets.c $(HDRS)
 	$(CC) $(CFLAGS) -S -o $@ $<
@@ -53,7 +62,4 @@ clean:
 	rm -f genapic/*.o genapic/*~ genapic/core
 	rm -f cpu/*.o cpu/*~ cpu/core
 
-delete-unfresh-files:
-	# nothing
-
-.PHONY: default clean delete-unfresh-files
+.PHONY: default clean
diff --git a/xen/arch/x86/traps.c b/xen/arch/x86/traps.c
index ab32049ec9..0889cd32bd 100644
--- a/xen/arch/x86/traps.c
+++ b/xen/arch/x86/traps.c
@@ -40,6 +40,7 @@
 #include <xen/perfc.h>
 #include <xen/softirq.h>
 #include <xen/domain_page.h>
+#include <xen/symbols.h>
 #include <asm/shadow.h>
 #include <asm/system.h>
 #include <asm/io.h>
@@ -100,7 +101,7 @@ unsigned long do_get_debugreg(int reg);
 static int debug_stack_lines = 20;
 integer_param("debug_stack_lines", debug_stack_lines);
 
-static inline int kernel_text_address(unsigned long addr)
+int is_kernel_text(unsigned long addr)
 {
     extern char _stext, _etext;
     if (addr >= (unsigned long) &_stext &&
@@ -110,6 +111,12 @@ static inline int kernel_text_address(unsigned long addr)
 
 }
 
+unsigned long kernel_text_end(void)
+{
+    extern char _etext;
+    return (unsigned long) &_etext;
+}
+
 void show_guest_stack(void)
 {
     int i;
@@ -150,11 +157,12 @@ void show_trace(unsigned long *esp)
     while ( ((long) stack & (STACK_SIZE-1)) != 0 )
     {
         addr = *stack++;
-        if ( kernel_text_address(addr) )
+        if ( is_kernel_text(addr) )
         {
             if ( (i != 0) && ((i % 6) == 0) )
                 printk("\n   ");
-            printk("[<%p>] ", _p(addr));
+            printk("[<%p>]", _p(addr));
+            print_symbol(" %s\n", addr);
             i++;
         }
     }
@@ -177,10 +185,7 @@ void show_stack(unsigned long *esp)
         if ( (i != 0) && ((i % 8) == 0) )
             printk("\n   ");
         addr = *stack++;
-        if ( kernel_text_address(addr) )
-            printk("[%p] ", _p(addr));
-        else
-            printk("%p ", _p(addr));
+        printk("%p ", _p(addr));
     }
     if ( i == 0 )
         printk("Stack empty.");
diff --git a/xen/arch/x86/x86_32/traps.c b/xen/arch/x86/x86_32/traps.c
index 29bb56a0b2..e6e8a11141 100644
--- a/xen/arch/x86/x86_32/traps.c
+++ b/xen/arch/x86/x86_32/traps.c
@@ -6,6 +6,7 @@
 #include <xen/console.h>
 #include <xen/mm.h>
 #include <xen/irq.h>
+#include <xen/symbols.h>
 #include <asm/current.h>
 #include <asm/flushtlb.h>
 #include <asm/vmx.h>
@@ -63,10 +64,10 @@ void show_registers(struct cpu_user_regs *regs)
         }
     }
 
-    printk("CPU:    %d\nEIP:    %04lx:[<%08lx>]      \nEFLAGS: %08lx   "
-           "CONTEXT: %s\n",
-           smp_processor_id(), (unsigned long)0xffff & regs->cs,
-           eip, eflags, context);
+    printk("CPU:    %d\nEIP:    %04lx:[<%08lx>]",
+           smp_processor_id(), (unsigned long)0xffff & regs->cs, eip);
+    print_symbol(" %s\n", eip);
+    printk("EFLAGS: %08lx   CONTEXT: %s\n", eflags, context);
     printk("eax: %08x   ebx: %08x   ecx: %08x   edx: %08x\n",
            regs->eax, regs->ebx, regs->ecx, regs->edx);
     printk("esi: %08x   edi: %08x   ebp: %08x   esp: %08lx\n",
@@ -119,8 +120,10 @@ asmlinkage void do_double_fault(void)
 
     /* Find information saved during fault and dump it to the console. */
     tss = &init_tss[cpu];
-    printk("CPU:    %d\nEIP:    %04x:[<%08x>]      \nEFLAGS: %08x\n",
-           cpu, tss->cs, tss->eip, tss->eflags);
+    printk("CPU:    %d\nEIP:    %04x:[<%08x>]",
+           cpu, tss->cs, tss->eip);
+    print_symbol(" %s\n", tss->eip);
+    printk("EFLAGS: %08x\n", tss->eflags);
     printk("CR3:    %08x\n", tss->__cr3);
     printk("eax: %08x   ebx: %08x   ecx: %08x   edx: %08x\n",
            tss->eax, tss->ebx, tss->ecx, tss->edx);
diff --git a/xen/arch/x86/x86_64/traps.c b/xen/arch/x86/x86_64/traps.c
index 0d7429cf14..c40a04359e 100644
--- a/xen/arch/x86/x86_64/traps.c
+++ b/xen/arch/x86/x86_64/traps.c
@@ -6,6 +6,7 @@
 #include <xen/errno.h>
 #include <xen/mm.h>
 #include <xen/irq.h>
+#include <xen/symbols.h>
 #include <xen/console.h>
 #include <xen/sched.h>
 #include <asm/current.h>
@@ -14,8 +15,10 @@
 
 void show_registers(struct cpu_user_regs *regs)
 {
-    printk("CPU:    %d\nEIP:    %04x:[<%016lx>]      \nEFLAGS: %016lx\n",
-           smp_processor_id(), 0xffff & regs->cs, regs->rip, regs->eflags);
+    printk("CPU:    %d\nEIP:    %04x:[<%016lx>]",
+           smp_processor_id(), 0xffff & regs->cs, regs->rip);
+    print_symbol(" %s\n", regs->rip);
+    printk("EFLAGS: %016lx\n", regs->eflags);
     printk("rax: %016lx   rbx: %016lx   rcx: %016lx   rdx: %016lx\n",
            regs->rax, regs->rbx, regs->rcx, regs->rdx);
     printk("rsi: %016lx   rdi: %016lx   rbp: %016lx   rsp: %016lx\n",
diff --git a/xen/common/symbols.c b/xen/common/symbols.c
new file mode 100644
index 0000000000..84e04d973c
--- /dev/null
+++ b/xen/common/symbols.c
@@ -0,0 +1,158 @@
+/*
+ * symbols.c: in-kernel printing of symbolic oopses and stack traces.
+ *
+ * Copyright 2002 Rusty Russell <rusty@rustcorp.com.au> IBM Corporation
+ *
+ * ChangeLog:
+ *
+ * (25/Aug/2004) Paulo Marques <pmarques@grupopie.com>
+ *      Changed the compression method from stem compression to "table lookup"
+ *      compression (see tools/symbols.c for a more complete description)
+ */
+
+#include <xen/config.h>
+#include <xen/symbols.h>
+#include <xen/init.h>
+#include <xen/lib.h>
+#include <xen/string.h>
+
+/* These will be re-linked against their real values during the second link stage */
+extern unsigned long symbols_addresses[] __attribute__((weak));
+extern unsigned long symbols_num_syms __attribute__((weak,section("data")));
+extern u8 symbols_names[] __attribute__((weak));
+
+extern u8 symbols_token_table[] __attribute__((weak));
+extern u16 symbols_token_index[] __attribute__((weak));
+
+extern unsigned long symbols_markers[] __attribute__((weak));
+
+/* expand a compressed symbol data into the resulting uncompressed string,
+   given the offset to where the symbol is in the compressed stream */
+static unsigned int symbols_expand_symbol(unsigned int off, char *result)
+{
+    int len, skipped_first = 0;
+    u8 *tptr, *data;
+
+    /* get the compressed symbol length from the first symbol byte */
+    data = &symbols_names[off];
+    len = *data;
+    data++;
+
+    /* update the offset to return the offset for the next symbol on
+     * the compressed stream */
+    off += len + 1;
+
+    /* for every byte on the compressed symbol data, copy the table
+       entry for that byte */
+    while(len) {
+        tptr = &symbols_token_table[ symbols_token_index[*data] ];
+        data++;
+        len--;
+
+        while (*tptr) {
+            if(skipped_first) {
+                *result = *tptr;
+                result++;
+            } else
+                skipped_first = 1;
+            tptr++;
+        }
+    }
+
+    *result = '\0';
+
+    /* return to offset to the next symbol */
+    return off;
+}
+
+/* find the offset on the compressed stream given and index in the
+ * symbols array */
+static unsigned int get_symbol_offset(unsigned long pos)
+{
+    u8 *name;
+    int i;
+
+    /* use the closest marker we have. We have markers every 256 positions,
+     * so that should be close enough */
+    name = &symbols_names[ symbols_markers[pos>>8] ];
+
+    /* sequentially scan all the symbols up to the point we're searching for.
+     * Every symbol is stored in a [<len>][<len> bytes of data] format, so we
+     * just need to add the len to the current pointer for every symbol we
+     * wish to skip */
+    for(i = 0; i < (pos&0xFF); i++)
+        name = name + (*name) + 1;
+
+    return name - symbols_names;
+}
+
+const char *symbols_lookup(unsigned long addr,
+                           unsigned long *symbolsize,
+                           unsigned long *offset,
+                           char *namebuf)
+{
+    unsigned long i, low, high, mid;
+    unsigned long symbol_end = 0;
+
+    /* This kernel should never had been booted. */
+    BUG_ON(!symbols_addresses);
+
+    namebuf[KSYM_NAME_LEN] = 0;
+    namebuf[0] = 0;
+
+    if (!is_kernel_text(addr))
+        return NULL;
+
+        /* do a binary search on the sorted symbols_addresses array */
+    low = 0;
+    high = symbols_num_syms;
+
+    while (high-low > 1) {
+        mid = (low + high) / 2;
+        if (symbols_addresses[mid] <= addr) low = mid;
+        else high = mid;
+    }
+
+    /* search for the first aliased symbol. Aliased symbols are
+           symbols with the same address */
+    while (low && symbols_addresses[low - 1] == symbols_addresses[low])
+        --low;
+
+        /* Grab name */
+    symbols_expand_symbol(get_symbol_offset(low), namebuf);
+
+    /* Search for next non-aliased symbol */
+    for (i = low + 1; i < symbols_num_syms; i++) {
+        if (symbols_addresses[i] > symbols_addresses[low]) {
+            symbol_end = symbols_addresses[i];
+            break;
+        }
+    }
+
+    /* if we found no next symbol, we use the end of the section */
+    if (!symbol_end)
+        symbol_end = kernel_text_end();
+
+    *symbolsize = symbol_end - symbols_addresses[low];
+    *offset = addr - symbols_addresses[low];
+    return namebuf;
+}
+
+/* Replace "%s" in format with address, or returns -errno. */
+void __print_symbol(const char *fmt, unsigned long address)
+{
+    const char *name;
+    unsigned long offset, size;
+    char namebuf[KSYM_NAME_LEN+1];
+    char buffer[sizeof("%s+%#lx/%#lx [%s]") + KSYM_NAME_LEN +
+               2*(BITS_PER_LONG*3/10) + 1];
+
+    name = symbols_lookup(address, &size, &offset, namebuf);
+
+    if (!name)
+        sprintf(buffer, "???");
+    else
+        sprintf(buffer, "%s+%#lx/%#lx", name, offset, size);
+
+    printk(fmt, buffer);
+}
diff --git a/xen/include/asm-x86/types.h b/xen/include/asm-x86/types.h
index 9cec42e7a7..fc83052f45 100644
--- a/xen/include/asm-x86/types.h
+++ b/xen/include/asm-x86/types.h
@@ -1,10 +1,9 @@
 #ifndef __X86_TYPES_H__
 #define __X86_TYPES_H__
 
-/*
- * __xx is ok: it doesn't pollute the POSIX namespace. Use these in the
- * header files exported to user space
- */
+#ifndef __ASSEMBLY__
+
+#include <xen/config.h>
 
 typedef __signed__ char __s8;
 typedef unsigned char __u8;
@@ -25,8 +24,6 @@ typedef unsigned long __u64;
 #endif
 #endif
 
-#include <xen/config.h>
-
 typedef signed char s8;
 typedef unsigned char u8;
 
@@ -39,9 +36,6 @@ typedef unsigned int u32;
 #if defined(__i386__)
 typedef signed long long s64;
 typedef unsigned long long u64;
-#define BITS_PER_LONG 32
-#define BYTES_PER_LONG 4
-#define LONG_BYTEORDER 2
 #if defined(CONFIG_X86_PAE)
 typedef u64 physaddr_t;
 #else
@@ -50,12 +44,21 @@ typedef u32 physaddr_t;
 #elif defined(__x86_64__)
 typedef signed long s64;
 typedef unsigned long u64;
-#define BITS_PER_LONG 64
-#define BYTES_PER_LONG 8
-#define LONG_BYTEORDER 3
 typedef u64 physaddr_t;
 #endif
 
 typedef unsigned long size_t;
 
+#endif /* __ASSEMBLY__ */
+
+#if defined(__i386__)
+#define BITS_PER_LONG 32
+#define BYTES_PER_LONG 4
+#define LONG_BYTEORDER 2
+#elif defined(__x86_64__)
+#define BITS_PER_LONG 64
+#define BYTES_PER_LONG 8
+#define LONG_BYTEORDER 3
+#endif
+
 #endif /* __X86_TYPES_H__ */
diff --git a/xen/include/xen/symbols.h b/xen/include/xen/symbols.h
new file mode 100644
index 0000000000..a30b82c002
--- /dev/null
+++ b/xen/include/xen/symbols.h
@@ -0,0 +1,45 @@
+#ifndef _XEN_SYMBOLS_H
+#define _XEN_SYMBOLS_H
+
+#include <xen/config.h>
+#include <xen/types.h>
+
+#define KSYM_NAME_LEN 127
+
+extern int is_kernel_text(unsigned long addr);
+extern unsigned long kernel_text_end(void);
+
+/* Lookup an address. */
+const char *symbols_lookup(unsigned long addr,
+                           unsigned long *symbolsize,
+                           unsigned long *offset,
+                           char *namebuf);
+
+/* Replace "%s" in format with address, if found */
+extern void __print_symbol(const char *fmt, unsigned long address);
+
+/* This macro allows us to keep printk typechecking */
+static void __check_printsym_format(const char *fmt, ...)
+    __attribute__((format(printf,1,2)));
+    static inline void __check_printsym_format(const char *fmt, ...)
+{
+}
+
+/* ia64 and ppc64 use function descriptors, which contain the real address */
+#if defined(CONFIG_IA64) || defined(CONFIG_PPC64)
+#define print_fn_descriptor_symbol(fmt, addr)		\
+do {						\
+	unsigned long *__faddr = (unsigned long*) addr;		\
+	print_symbol(fmt, __faddr[0]);		\
+} while (0)
+#else
+#define print_fn_descriptor_symbol(fmt, addr) print_symbol(fmt, addr)
+#endif
+
+#define print_symbol(fmt, addr)			\
+do {						\
+	__check_printsym_format(fmt, "");	\
+	__print_symbol(fmt, addr);		\
+} while(0)
+
+#endif /*_XEN_SYMBOLS_H*/
diff --git a/xen/tools/Makefile b/xen/tools/Makefile
index 8252970158..04d7020cd8 100644
--- a/xen/tools/Makefile
+++ b/xen/tools/Makefile
@@ -1,6 +1,13 @@
 
+include $(BASEDIR)/../Config.mk
+
 default:
 	$(MAKE) -C figlet
+	$(MAKE) symbols
 
 clean:
-	$(MAKE) -C figlet clean
\ No newline at end of file
+	$(MAKE) -C figlet clean
+	rm -f *.o symbols
+
+symbols: symbols.c
+	$(HOSTCC) -o $@ $<
diff --git a/xen/tools/symbols.c b/xen/tools/symbols.c
new file mode 100644
index 0000000000..a5665cc124
--- /dev/null
+++ b/xen/tools/symbols.c
@@ -0,0 +1,716 @@
+/* Generate assembler source containing symbol information
+ *
+ * Copyright 2002       by Kai Germaschewski
+ *
+ * This software may be used and distributed according to the terms
+ * of the GNU General Public License, incorporated herein by reference.
+ *
+ * Usage: nm -n <object-file> | scripts/symbols [--all-symbols] > symbols.S
+ *
+ * ChangeLog:
+ *
+ * (25/Aug/2004) Paulo Marques <pmarques@grupopie.com>
+ *      Changed the compression method from stem compression to "table lookup"
+ *      compression
+ *
+ *      Table compression uses all the unused char codes on the symbols and
+ *  maps these to the most used substrings (tokens). For instance, it might
+ *  map char code 0xF7 to represent "write_" and then in every symbol where
+ *  "write_" appears it can be replaced by 0xF7, saving 5 bytes.
+ *      The used codes themselves are also placed in the table so that the
+ *  decompresion can work without "special cases".
+ *      Applied to kernel symbols, this usually produces a compression ratio
+ *  of about 50%.
+ *
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <ctype.h>
+
+/* maximum token length used. It doesn't pay to increase it a lot, because
+ * very long substrings probably don't repeat themselves too often. */
+#define MAX_TOK_SIZE		11
+#define KSYM_NAME_LEN		127
+
+/* we use only a subset of the complete symbol table to gather the token count,
+ * to speed up compression, at the expense of a little compression ratio */
+#define WORKING_SET		1024
+
+/* first find the best token only on the list of tokens that would profit more
+ * than GOOD_BAD_THRESHOLD. Only if this list is empty go to the "bad" list.
+ * Increasing this value will put less tokens on the "good" list, so the search
+ * is faster. However, if the good list runs out of tokens, we must painfully
+ * search the bad list. */
+#define GOOD_BAD_THRESHOLD	10
+
+/* token hash parameters */
+#define HASH_BITS		18
+#define HASH_TABLE_SIZE		(1 << HASH_BITS)
+#define HASH_MASK		(HASH_TABLE_SIZE - 1)
+#define HASH_BASE_OFFSET	2166136261U
+#define HASH_FOLD(a)		((a)&(HASH_MASK))
+
+/* flags to mark symbols */
+#define SYM_FLAG_VALID		1
+#define SYM_FLAG_SAMPLED	2
+
+struct sym_entry {
+	unsigned long long addr;
+	char type;
+	unsigned char flags;
+	unsigned char len;
+	unsigned char *sym;
+};
+
+
+static struct sym_entry *table;
+static int size, cnt;
+static unsigned long long _stext, _etext;
+static int all_symbols = 0;
+static char symbol_prefix_char = '\0';
+
+struct token {
+	unsigned char data[MAX_TOK_SIZE];
+	unsigned char len;
+	/* profit: the number of bytes that could be saved by inserting this
+	 * token into the table */
+	int profit;
+	struct token *next;	/* next token on the hash list */
+	struct token *right;	/* next token on the good/bad list */
+	struct token *left;    /* previous token on the good/bad list */
+	struct token *smaller; /* token that is less one letter than this one */
+	};
+
+struct token bad_head, good_head;
+struct token *hash_table[HASH_TABLE_SIZE];
+
+/* the table that holds the result of the compression */
+unsigned char best_table[256][MAX_TOK_SIZE+1];
+unsigned char best_table_len[256];
+
+
+static void
+usage(void)
+{
+	fprintf(stderr, "Usage: symbols [--all-symbols] [--symbol-prefix=<prefix char>] < in.map > out.S\n");
+	exit(1);
+}
+
+/*
+ * This ignores the intensely annoying "mapping symbols" found
+ * in ARM ELF files: $a, $t and $d.
+ */
+static inline int
+is_arm_mapping_symbol(const char *str)
+{
+	return str[0] == '$' && strchr("atd", str[1])
+	       && (str[2] == '\0' || str[2] == '.');
+}
+
+static int
+read_symbol(FILE *in, struct sym_entry *s)
+{
+	char str[500];
+	char *sym;
+	int rc;
+
+	rc = fscanf(in, "%llx %c %499s\n", &s->addr, &s->type, str);
+	if (rc != 3) {
+		if (rc != EOF) {
+			/* skip line */
+			fgets(str, 500, in);
+		}
+		return -1;
+	}
+
+	sym = str;
+	/* skip prefix char */
+	if (symbol_prefix_char && str[0] == symbol_prefix_char)
+		sym++;
+
+	/* Ignore most absolute/undefined (?) symbols. */
+	if (strcmp(sym, "_stext") == 0)
+		_stext = s->addr;
+	else if (strcmp(sym, "_etext") == 0)
+		_etext = s->addr;
+	else if (toupper(s->type) == 'A')
+	{
+		/* Keep these useful absolute symbols */
+		if (strcmp(sym, "__kernel_syscall_via_break") &&
+		    strcmp(sym, "__kernel_syscall_via_epc") &&
+		    strcmp(sym, "__kernel_sigtramp") &&
+		    strcmp(sym, "__gp"))
+			return -1;
+
+	}
+	else if (toupper(s->type) == 'U' ||
+		 is_arm_mapping_symbol(sym))
+		return -1;
+
+	/* include the type field in the symbol name, so that it gets
+	 * compressed together */
+	s->len = strlen(str) + 1;
+	s->sym = (char *) malloc(s->len + 1);
+	strcpy(s->sym + 1, str);
+	s->sym[0] = s->type;
+
+	return 0;
+}
+
+static int
+symbol_valid(struct sym_entry *s)
+{
+	/* Symbols which vary between passes.  Passes 1 and 2 must have
+	 * identical symbol lists.  The symbols_* symbols below are only added
+	 * after pass 1, they would be included in pass 2 when --all-symbols is
+	 * specified so exclude them to get a stable symbol list.
+	 */
+	static char *special_symbols[] = {
+		"symbols_addresses",
+		"symbols_num_syms",
+		"symbols_names",
+		"symbols_markers",
+		"symbols_token_table",
+		"symbols_token_index",
+
+	/* Exclude linker generated symbols which vary between passes */
+		"_SDA_BASE_",		/* ppc */
+		"_SDA2_BASE_",		/* ppc */
+		NULL };
+	int i;
+	int offset = 1;
+
+	/* skip prefix char */
+	if (symbol_prefix_char && *(s->sym + 1) == symbol_prefix_char)
+		offset++;
+
+	/* if --all-symbols is not specified, then symbols outside the text
+	 * and inittext sections are discarded */
+	if (!all_symbols) {
+		if (s->addr < _stext || s->addr > _etext)
+			return 0;
+		/* Corner case.  Discard any symbols with the same value as
+		 * _etext _einittext or _eextratext; they can move between pass
+		 * 1 and 2 when the symbols data are added.  If these symbols
+		 * move then they may get dropped in pass 2, which breaks the
+		 * symbols rules.
+		 */
+		if (s->addr == _etext && strcmp(s->sym + offset, "_etext"))
+			return 0;
+	}
+
+	/* Exclude symbols which vary between passes. */
+	if (strstr(s->sym + offset, "_compiled."))
+		return 0;
+
+	for (i = 0; special_symbols[i]; i++)
+		if( strcmp(s->sym + offset, special_symbols[i]) == 0 )
+			return 0;
+
+	return 1;
+}
+
+static void
+read_map(FILE *in)
+{
+	while (!feof(in)) {
+		if (cnt >= size) {
+			size += 10000;
+			table = realloc(table, sizeof(*table) * size);
+			if (!table) {
+				fprintf(stderr, "out of memory\n");
+				exit (1);
+			}
+		}
+		if (read_symbol(in, &table[cnt]) == 0)
+			cnt++;
+	}
+}
+
+static void output_label(char *label)
+{
+	if (symbol_prefix_char)
+		printf(".globl %c%s\n", symbol_prefix_char, label);
+	else
+		printf(".globl %s\n", label);
+	printf("\tALGN\n");
+	if (symbol_prefix_char)
+		printf("%c%s:\n", symbol_prefix_char, label);
+	else
+		printf("%s:\n", label);
+}
+
+/* uncompress a compressed symbol. When this function is called, the best table
+ * might still be compressed itself, so the function needs to be recursive */
+static int expand_symbol(unsigned char *data, int len, char *result)
+{
+	int c, rlen, total=0;
+
+	while (len) {
+		c = *data;
+		/* if the table holds a single char that is the same as the one
+		 * we are looking for, then end the search */
+		if (best_table[c][0]==c && best_table_len[c]==1) {
+			*result++ = c;
+			total++;
+		} else {
+			/* if not, recurse and expand */
+			rlen = expand_symbol(best_table[c], best_table_len[c], result);
+			total += rlen;
+			result += rlen;
+		}
+		data++;
+		len--;
+	}
+	*result=0;
+
+	return total;
+}
+
+static void
+write_src(void)
+{
+	int i, k, off, valid;
+	unsigned int best_idx[256];
+	unsigned int *markers;
+	char buf[KSYM_NAME_LEN+1];
+
+	printf("#include <asm/types.h>\n");
+	printf("#if BITS_PER_LONG == 64\n");
+	printf("#define PTR .quad\n");
+	printf("#define ALGN .align 8\n");
+	printf("#else\n");
+	printf("#define PTR .long\n");
+	printf("#define ALGN .align 4\n");
+	printf("#endif\n");
+
+	printf(".data\n");
+
+	output_label("symbols_addresses");
+	valid = 0;
+	for (i = 0; i < cnt; i++) {
+		if (table[i].flags & SYM_FLAG_VALID) {
+			printf("\tPTR\t%#llx\n", table[i].addr);
+			valid++;
+		}
+	}
+	printf("\n");
+
+	output_label("symbols_num_syms");
+	printf("\tPTR\t%d\n", valid);
+	printf("\n");
+
+	/* table of offset markers, that give the offset in the compressed stream
+	 * every 256 symbols */
+	markers = (unsigned int *) malloc(sizeof(unsigned int)*((valid + 255) / 256));
+
+	output_label("symbols_names");
+	valid = 0;
+	off = 0;
+	for (i = 0; i < cnt; i++) {
+
+		if (!table[i].flags & SYM_FLAG_VALID)
+			continue;
+
+		if ((valid & 0xFF) == 0)
+			markers[valid >> 8] = off;
+
+		printf("\t.byte 0x%02x", table[i].len);
+		for (k = 0; k < table[i].len; k++)
+			printf(", 0x%02x", table[i].sym[k]);
+		printf("\n");
+
+		off += table[i].len + 1;
+		valid++;
+	}
+	printf("\n");
+
+	output_label("symbols_markers");
+	for (i = 0; i < ((valid + 255) >> 8); i++)
+		printf("\tPTR\t%d\n", markers[i]);
+	printf("\n");
+
+	free(markers);
+
+	output_label("symbols_token_table");
+	off = 0;
+	for (i = 0; i < 256; i++) {
+		best_idx[i] = off;
+		expand_symbol(best_table[i],best_table_len[i],buf);
+		printf("\t.asciz\t\"%s\"\n", buf);
+		off += strlen(buf) + 1;
+	}
+	printf("\n");
+
+	output_label("symbols_token_index");
+	for (i = 0; i < 256; i++)
+		printf("\t.short\t%d\n", best_idx[i]);
+	printf("\n");
+}
+
+
+/* table lookup compression functions */
+
+static inline unsigned int rehash_token(unsigned int hash, unsigned char data)
+{
+	return ((hash * 16777619) ^ data);
+}
+
+static unsigned int hash_token(unsigned char *data, int len)
+{
+	unsigned int hash=HASH_BASE_OFFSET;
+	int i;
+
+	for (i = 0; i < len; i++)
+		hash = rehash_token(hash, data[i]);
+
+	return HASH_FOLD(hash);
+}
+
+/* find a token given its data and hash value */
+static struct token *find_token_hash(unsigned char *data, int len, unsigned int hash)
+{
+	struct token *ptr;
+
+	ptr = hash_table[hash];
+
+	while (ptr) {
+		if ((ptr->len == len) && (memcmp(ptr->data, data, len) == 0))
+			return ptr;
+		ptr=ptr->next;
+	}
+
+	return NULL;
+}
+
+static inline void insert_token_in_group(struct token *head, struct token *ptr)
+{
+	ptr->right = head->right;
+	ptr->right->left = ptr;
+	head->right = ptr;
+	ptr->left = head;
+}
+
+static inline void remove_token_from_group(struct token *ptr)
+{
+	ptr->left->right = ptr->right;
+	ptr->right->left = ptr->left;
+}
+
+
+/* build the counts for all the tokens that start with "data", and have lenghts
+ * from 2 to "len" */
+static void learn_token(unsigned char *data, int len)
+{
+	struct token *ptr,*last_ptr;
+	int i, newprofit;
+	unsigned int hash = HASH_BASE_OFFSET;
+	unsigned int hashes[MAX_TOK_SIZE + 1];
+
+	if (len > MAX_TOK_SIZE)
+		len = MAX_TOK_SIZE;
+
+	/* calculate and store the hash values for all the sub-tokens */
+	hash = rehash_token(hash, data[0]);
+	for (i = 2; i <= len; i++) {
+		hash = rehash_token(hash, data[i-1]);
+		hashes[i] = HASH_FOLD(hash);
+	}
+
+	last_ptr = NULL;
+	ptr = NULL;
+
+	for (i = len; i >= 2; i--) {
+		hash = hashes[i];
+
+		if (!ptr) ptr = find_token_hash(data, i, hash);
+
+		if (!ptr) {
+			/* create a new token entry */
+			ptr = (struct token *) malloc(sizeof(*ptr));
+
+			memcpy(ptr->data, data, i);
+			ptr->len = i;
+
+			/* when we create an entry, it's profit is 0 because
+			 * we also take into account the size of the token on
+			 * the compressed table. We then subtract GOOD_BAD_THRESHOLD
+			 * so that the test to see if this token belongs to
+			 * the good or bad list, is a comparison to zero */
+			ptr->profit = -GOOD_BAD_THRESHOLD;
+
+			ptr->next = hash_table[hash];
+			hash_table[hash] = ptr;
+
+			insert_token_in_group(&bad_head, ptr);
+
+			ptr->smaller = NULL;
+		} else {
+			newprofit = ptr->profit + (ptr->len - 1);
+			/* check to see if this token needs to be moved to a
+			 * different list */
+			if((ptr->profit < 0) && (newprofit >= 0)) {
+				remove_token_from_group(ptr);
+				insert_token_in_group(&good_head,ptr);
+			}
+			ptr->profit = newprofit;
+		}
+
+		if (last_ptr) last_ptr->smaller = ptr;
+		last_ptr = ptr;
+
+		ptr = ptr->smaller;
+	}
+}
+
+/* decrease the counts for all the tokens that start with "data", and have lenghts
+ * from 2 to "len". This function is much simpler than learn_token because we have
+ * more guarantees (tho tokens exist, the ->smaller pointer is set, etc.)
+ * The two separate functions exist only because of compression performance */
+static void forget_token(unsigned char *data, int len)
+{
+	struct token *ptr;
+	int i, newprofit;
+	unsigned int hash=0;
+
+	if (len > MAX_TOK_SIZE) len = MAX_TOK_SIZE;
+
+	hash = hash_token(data, len);
+	ptr = find_token_hash(data, len, hash);
+
+	for (i = len; i >= 2; i--) {
+
+		newprofit = ptr->profit - (ptr->len - 1);
+		if ((ptr->profit >= 0) && (newprofit < 0)) {
+			remove_token_from_group(ptr);
+			insert_token_in_group(&bad_head, ptr);
+		}
+		ptr->profit=newprofit;
+
+		ptr=ptr->smaller;
+	}
+}
+
+/* count all the possible tokens in a symbol */
+static void learn_symbol(unsigned char *symbol, int len)
+{
+	int i;
+
+	for (i = 0; i < len - 1; i++)
+		learn_token(symbol + i, len - i);
+}
+
+/* decrease the count for all the possible tokens in a symbol */
+static void forget_symbol(unsigned char *symbol, int len)
+{
+	int i;
+
+	for (i = 0; i < len - 1; i++)
+		forget_token(symbol + i, len - i);
+}
+
+/* set all the symbol flags and do the initial token count */
+static void build_initial_tok_table(void)
+{
+	int i, use_it, valid;
+
+	valid = 0;
+	for (i = 0; i < cnt; i++) {
+		table[i].flags = 0;
+		if ( symbol_valid(&table[i]) ) {
+			table[i].flags |= SYM_FLAG_VALID;
+			valid++;
+		}
+	}
+
+	use_it = 0;
+	for (i = 0; i < cnt; i++) {
+
+		/* subsample the available symbols. This method is almost like
+		 * a Bresenham's algorithm to get uniformly distributed samples
+		 * across the symbol table */
+		if (table[i].flags & SYM_FLAG_VALID) {
+
+			use_it += WORKING_SET;
+
+			if (use_it >= valid) {
+				table[i].flags |= SYM_FLAG_SAMPLED;
+				use_it -= valid;
+			}
+		}
+		if (table[i].flags & SYM_FLAG_SAMPLED)
+			learn_symbol(table[i].sym, table[i].len);
+	}
+}
+
+/* replace a given token in all the valid symbols. Use the sampled symbols
+ * to update the counts */
+static void compress_symbols(unsigned char *str, int tlen, int idx)
+{
+	int i, len, learn, size;
+	unsigned char *p;
+
+	for (i = 0; i < cnt; i++) {
+
+		if (!(table[i].flags & SYM_FLAG_VALID)) continue;
+
+		len = table[i].len;
+		learn = 0;
+		p = table[i].sym;
+
+		do {
+			/* find the token on the symbol */
+			p = (unsigned char *) strstr((char *) p, (char *) str);
+			if (!p) break;
+
+			if (!learn) {
+				/* if this symbol was used to count, decrease it */
+				if (table[i].flags & SYM_FLAG_SAMPLED)
+					forget_symbol(table[i].sym, len);
+				learn = 1;
+			}
+
+			*p = idx;
+			size = (len - (p - table[i].sym)) - tlen + 1;
+			memmove(p + 1, p + tlen, size);
+			p++;
+			len -= tlen - 1;
+
+		} while (size >= tlen);
+
+		if(learn) {
+			table[i].len = len;
+			/* if this symbol was used to count, learn it again */
+			if(table[i].flags & SYM_FLAG_SAMPLED)
+				learn_symbol(table[i].sym, len);
+		}
+	}
+}
+
+/* search the token with the maximum profit */
+static struct token *find_best_token(void)
+{
+	struct token *ptr,*best,*head;
+	int bestprofit;
+
+	bestprofit=-10000;
+
+	/* failsafe: if the "good" list is empty search from the "bad" list */
+	if(good_head.right == &good_head) head = &bad_head;
+	else head = &good_head;
+
+	ptr = head->right;
+	best = NULL;
+	while (ptr != head) {
+		if (ptr->profit > bestprofit) {
+			bestprofit = ptr->profit;
+			best = ptr;
+		}
+		ptr = ptr->right;
+	}
+
+	return best;
+}
+
+/* this is the core of the algorithm: calculate the "best" table */
+static void optimize_result(void)
+{
+	struct token *best;
+	int i;
+
+	/* using the '\0' symbol last allows compress_symbols to use standard
+	 * fast string functions */
+	for (i = 255; i >= 0; i--) {
+
+		/* if this table slot is empty (it is not used by an actual
+		 * original char code */
+		if (!best_table_len[i]) {
+
+			/* find the token with the breates profit value */
+			best = find_best_token();
+
+			/* place it in the "best" table */
+			best_table_len[i] = best->len;
+			memcpy(best_table[i], best->data, best_table_len[i]);
+			/* zero terminate the token so that we can use strstr
+			   in compress_symbols */
+			best_table[i][best_table_len[i]]='\0';
+
+			/* replace this token in all the valid symbols */
+			compress_symbols(best_table[i], best_table_len[i], i);
+		}
+	}
+}
+
+/* start by placing the symbols that are actually used on the table */
+static void insert_real_symbols_in_table(void)
+{
+	int i, j, c;
+
+	memset(best_table, 0, sizeof(best_table));
+	memset(best_table_len, 0, sizeof(best_table_len));
+
+	for (i = 0; i < cnt; i++) {
+		if (table[i].flags & SYM_FLAG_VALID) {
+			for (j = 0; j < table[i].len; j++) {
+				c = table[i].sym[j];
+				best_table[c][0]=c;
+				best_table_len[c]=1;
+			}
+		}
+	}
+}
+
+static void optimize_token_table(void)
+{
+	memset(hash_table, 0, sizeof(hash_table));
+
+	good_head.left = &good_head;
+	good_head.right = &good_head;
+
+	bad_head.left = &bad_head;
+	bad_head.right = &bad_head;
+
+	build_initial_tok_table();
+
+	insert_real_symbols_in_table();
+
+	/* When valid symbol is not registered, exit to error */
+	if (good_head.left == good_head.right &&
+	    bad_head.left == bad_head.right) {
+		fprintf(stderr, "No valid symbol.\n");
+		exit(1);
+	}
+
+	optimize_result();
+}
+
+
+int
+main(int argc, char **argv)
+{
+	if (argc >= 2) {
+		int i;
+		for (i = 1; i < argc; i++) {
+			if(strcmp(argv[i], "--all-symbols") == 0)
+				all_symbols = 1;
+			else if (strncmp(argv[i], "--symbol-prefix=", 16) == 0) {
+				char *p = &argv[i][16];
+				/* skip quote */
+				if ((*p == '"' && *(p+2) == '"') || (*p == '\'' && *(p+2) == '\''))
+					p++;
+				symbol_prefix_char = *p;
+			} else
+				usage();
+		}
+	} else if (argc != 1)
+		usage();
+
+	read_map(stdin);
+	optimize_token_table();
+	write_src();
+
+	return 0;
+}