Provide convenience function for obtaining MODINFO_ADDR and MODINFO_SIZE

attributes for preloaded modules/images. In particular, MODINFO_ADDR has
the added complexity of not always being relocated properly. Rather than
kluging this in the various components that are affected, we handle it
in a centralized place (preload_fetch_addr()). To that end, expose a new
variable, preload_addr_relocate, that MD initialization code can set and
that turns the address attribute into a valid kernel VA.

Architectures that need the relocation: arm & powerpc (at least).
Components that can utilize this: acpi(4), md(4), fb(4), pci(4), ZFS, geli.

Sponsored by: Juniper Networks

2 files changed, 28 insertions, 1 deletions

diff --git a/sys/kern/subr_module.c b/sys/kern/subr_module.c
index 1295cb8..2485c94 100644
--- a/sys/kern/subr_module.c
+++ b/sys/kern/subr_module.c
@@ -35,7 +35,8 @@ __FBSDID("$FreeBSD$");
  * Preloaded module support
  */
 
-caddr_t	preload_metadata;
+vm_offset_t preload_addr_relocate = 0;
+caddr_t preload_metadata;
 
 /*
  * Search for the preloaded module (name)
@@ -230,6 +231,28 @@ preload_delete_name(const char *name)
     }
 }
 
+void *
+preload_fetch_addr(caddr_t mod)
+{
+	caddr_t *mdp;
+
+	mdp = (caddr_t *)preload_search_info(mod, MODINFO_ADDR);
+	if (mdp == NULL)
+		return (NULL);
+	return (*mdp + preload_addr_relocate);
+}
+
+size_t
+preload_fetch_size(caddr_t mod)
+{
+	size_t *mdp;
+
+	mdp = (size_t *)preload_search_info(mod, MODINFO_SIZE);
+	if (mdp == NULL)
+		return (0);
+	return (*mdp);
+}
+
 /* Called from locore on i386.  Convert physical pointers to kvm. Sigh. */
 void
 preload_bootstrap_relocate(vm_offset_t offset)
diff --git a/sys/sys/linker.h b/sys/sys/linker.h
index aa705fd..8ea140f 100644
--- a/sys/sys/linker.h
+++ b/sys/sys/linker.h
@@ -234,7 +234,11 @@ void *linker_hwpmc_list_objects(void);
 /*
  * Module lookup
  */
+extern vm_offset_t	preload_addr_relocate;
 extern caddr_t		preload_metadata;
+
+extern void *		preload_fetch_addr(caddr_t _mod);
+extern size_t		preload_fetch_size(caddr_t _mod);
 extern caddr_t		preload_search_by_name(const char *_name);
 extern caddr_t		preload_search_by_type(const char *_type);
 extern caddr_t		preload_search_next_name(caddr_t _base);