The kernel linker includes a number of utility functions to look up symbol

information in support of DDB(4); these functions bypass normal linker
locking as they may run in contexts where locking is unsafe (such as the
kernel debugger).

Add a new interface linker_ddb_search_symbol_name(), which looks up a
symbol name and offset given an address, and also
linker_search_symbol_name() which does the same but *does* follow the
locking conventions of the linker.

Unlike existing functions, these functions place the name in a
caller-provided buffer, which is stable even after linker locks have been
released.  These functions will be used in upcoming revisions to stack(9)
to support kernel stack trace generation in contexts as part of a live,
rather than suspended, kernel.

1 files changed, 8 insertions, 0 deletions

diff --git a/sys/sys/linker.h b/sys/sys/linker.h
index c5087c8..6655d46 100644
--- a/sys/sys/linker.h
+++ b/sys/sys/linker.h
@@ -176,6 +176,14 @@ int linker_ddb_lookup(const char *_symstr, c_linker_sym_t *_sym);
 int linker_ddb_search_symbol(caddr_t _value, c_linker_sym_t *_sym,
 			     long *_diffp);
 int linker_ddb_symbol_values(c_linker_sym_t _sym, linker_symval_t *_symval);
+int linker_ddb_search_symbol_name(caddr_t value, char *buf, u_int buflen,
+				  long *offset);
+
+/*
+ * stack(9) helper for situations where kernel locking is required.
+ */
+int linker_search_symbol_name(caddr_t value, char *buf, u_int buflen,
+    long *offset);
 
 
 /* HWPMC helper */