MFP4: Support for profiling dynamically loaded objects.

Kernel changes:

  Inform hwpmc of executable objects brought into the system by
  kldload() and mmap(), and of their removal by kldunload() and
  munmap().  A helper function linker_hwpmc_list_objects() has been
  added to "sys/kern/kern_linker.c" and is used by hwpmc to retrieve
  the list of currently loaded kernel modules.

  The unused `MAPPINGCHANGE' event has been deprecated in favour
  of separate `MAP_IN' and `MAP_OUT' events; this change reduces
  space wastage in the log.

  Bump the hwpmc's ABI version to "2.0.00".  Teach hwpmc(4) to
  handle the map change callbacks.

  Change the default per-cpu sample buffer size to hold
  32 samples (up from 16).

  Increment __FreeBSD_version.

libpmc(3) changes:

  Update libpmc(3) to deal with the new events in the log file; bring
  the pmclog(3) manual page in sync with the code.

pmcstat(8) changes:

  Introduce new options to pmcstat(8): "-r" (root fs path), "-M"
  (mapfile name), "-q"/"-v" (verbosity control).  Option "-k" now
  takes a kernel directory as its argument but will also work with
  the older invocation syntax.

  Rework string handling in pmcstat(8) to use an opaque type for
  interned strings.  Clean up ELF parsing code and add support for
  tracking dynamic object mappings reported by a v2.0.00 hwpmc(4).

  Report statistics at the end of a log conversion run depending
  on the requested verbosity level.

Reviewed by:	jhb, dds (kernel parts of an earlier patch)
Tested by:	gallatin (earlier patch)

1 files changed, 78 insertions, 0 deletions

diff --git a/sys/kern/kern_linker.c b/sys/kern/kern_linker.c
index ca05cc0..a48cfd2 100644
--- a/sys/kern/kern_linker.c
+++ b/sys/kern/kern_linker.c
@@ -28,6 +28,7 @@
 __FBSDID("$FreeBSD$");
 
 #include "opt_ddb.h"
+#include "opt_hwpmc_hooks.h"
 #include "opt_mac.h"
 
 #include <sys/param.h>
@@ -51,6 +52,10 @@ __FBSDID("$FreeBSD$");
 
 #include "linker_if.h"
 
+#ifdef HWPMC_HOOKS
+#include <sys/pmckern.h>
+#endif
+
 #ifdef KLD_DEBUG
 int kld_debug = 0;
 #endif
@@ -751,6 +756,9 @@ linker_ddb_symbol_values(c_linker_sym_t sym, linker_symval_t *symval)
 int
 kldload(struct thread *td, struct kldload_args *uap)
 {
+#ifdef HWPMC_HOOKS
+	struct pmckern_map_in pkm;
+#endif
 	char *kldname, *modname;
 	char *pathname = NULL;
 	linker_file_t lf;
@@ -786,6 +794,11 @@ kldload(struct thread *td, struct kldload_args *uap)
 	if (error)
 		goto out;
 
+#ifdef HWPMC_HOOKS
+	pkm.pm_file = lf->filename;
+	pkm.pm_address = (uintptr_t) lf->address;
+	PMC_CALL_HOOK(td, PMC_FN_KLD_LOAD, (void *) &pkm);
+#endif
 	lf->userrefs++;
 	td->td_retval[0] = lf->id;
 out:
@@ -801,6 +814,9 @@ out:
 static int
 kern_kldunload(struct thread *td, int fileid, int flags)
 {
+#ifdef HWPMC_HOOKS
+	struct pmckern_map_out pkm;
+#endif
 	linker_file_t lf;
 	int error = 0;
 
@@ -825,11 +841,21 @@ kern_kldunload(struct thread *td, int fileid, int flags)
 			goto out;
 		}
 		lf->userrefs--;
+#ifdef HWPMC_HOOKS
+		/* Save data needed by hwpmc(4) before unloading the kld. */
+		pkm.pm_address = (uintptr_t) lf->address;
+		pkm.pm_size = lf->size;
+#endif
 		error = linker_file_unload(lf, flags);
 		if (error)
 			lf->userrefs++;
 	} else
 		error = ENOENT;
+
+#ifdef HWPMC_HOOKS
+	if (error == 0)
+		PMC_CALL_HOOK(td, PMC_FN_KLD_UNLOAD, (void *) &pkm);
+#endif
 out:
 	mtx_unlock(&Giant);
 	return (error);
@@ -1659,6 +1685,58 @@ linker_basename(const char *path)
 	return (filename);
 }
 
+#ifdef HWPMC_HOOKS
+
+/*
+ * Inform hwpmc about the set of kernel modules currently loaded.
+ */
+void *
+linker_hwpmc_list_objects(void)
+{
+	int nobjects, nmappings;
+	linker_file_t lf;
+	struct pmckern_map_in *ko, *kobase;
+
+	nmappings = 15;	/* a reasonable default */
+
+ retry:
+	/* allocate nmappings+1 entries */
+	MALLOC(kobase, struct pmckern_map_in *,
+	    (nmappings + 1) * sizeof(struct pmckern_map_in), M_LINKER,
+	    M_WAITOK | M_ZERO);
+
+	nobjects = 0;
+	mtx_lock(&kld_mtx);
+	TAILQ_FOREACH(lf, &linker_files, link)
+		nobjects++;
+
+	KASSERT(nobjects > 0, ("linker_hpwmc_list_objects: no kernel "
+		"objects?"));
+
+	if (nobjects > nmappings) {
+		nmappings = nobjects;
+		FREE(kobase, M_LINKER);
+		mtx_unlock(&kld_mtx);
+		goto retry;
+	}
+
+	ko = kobase;
+	TAILQ_FOREACH(lf, &linker_files, link) {
+		ko->pm_file = lf->filename;
+		ko->pm_address = (uintptr_t) lf->address;
+		ko++;
+	}
+
+	/* The last entry of the malloced area comprises of all zeros. */
+	KASSERT(ko->pm_file == NULL,
+	    ("linker_hwpmc_list_objects: last object not NULL"));
+
+	mtx_unlock(&kld_mtx);
+
+	return ((void *) kobase);
+}
+#endif
+
 /*
  * Find a file which contains given module and load it, if "parent" is not
  * NULL, register a reference to it.