Port kallsyms to Xen, as 'symbols'.

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

1 files changed, 158 insertions, 0 deletions

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);
+}