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-rw-r--r--ldso/ldso/i386/resolve.S18
1 files changed, 17 insertions, 1 deletions
diff --git a/ldso/ldso/i386/resolve.S b/ldso/ldso/i386/resolve.S
index 4abf243f4..97948ef91 100644
--- a/ldso/ldso/i386/resolve.S
+++ b/ldso/ldso/i386/resolve.S
@@ -1,5 +1,21 @@
/*
- * These are various helper routines that are needed to run an ELF image.
+ * This function is _not_ called directly. It is jumped to (so no return
+ * address is on the stack) when attempting to use a symbol that has not yet
+ * been resolved. The first time a jump symbol (such as a function call inside
+ * a shared library) is used (before it gets resolved) it will jump here to
+ * _dl_linux_resolve. When we get called the stack looks like this:
+ * reloc_entry
+ * tpnt
+
+ * This function saves all the registers, puts a copy of reloc_entry and tpnt
+ * on the stack (as function arguments) then make the function call
+ * _dl_linux_resolver(tpnt, reloc_entry). _dl_linux_resolver() figures out
+ * where the jump symbol is _really_ supposed to have jumped to and returns
+ * that to us. Once we have that, we overwrite tpnt with this fixed up
+ * address. We then clean up after ourselves, put all the registers back how we
+ * found them, then we jump to where the fixed up address, which is where the
+ * jump symbol that got us here really wanted to jump to in the first place.
+ * -Erik Andersen
*/
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