Add support for getmajor() and getminor() subroutines

Signed-off-by: Eugene Loh <eugene.loh@oracle.com> Reviewed-by: Kris Van Hees <kris.van.hees@oracle.com>
oracle · Apr 21, 2022 · ebfecdf · ebfecdf
1 parent 14b51ea
commit ebfecdf
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Showing 5 changed files with 68 additions and 2 deletions.
diff --git a/libdtrace/dt_cg.c b/libdtrace/dt_cg.c
@@ -3949,6 +3949,32 @@ dt_cg_subr_rindex(dt_node_t *dnp, dt_irlist_t *dlp, dt_regset_t *drp)
 	TRACE_REGSET("    subr-rindex:End  ");
 }
 
+/*
+ * For getmajor and getminor, use MAJOR(dev) and MINOR(dev)
+ * as defined in kernel header include/linux/kdev_t.h, not
+ * as defined in user header /usr/include/linux/kdev_t.h.
+ */
+static void
+dt_cg_subr_getmajor(dt_node_t *dnp, dt_irlist_t *dlp, dt_regset_t *drp)
+{
+	dt_node_t	*arg = dnp->dn_args;
+
+	dt_cg_node(arg, dlp, drp);
+	dnp->dn_reg = arg->dn_reg;
+	emit(dlp, BPF_ALU64_IMM(BPF_LSH, dnp->dn_reg, 32));
+	emit(dlp, BPF_ALU64_IMM(BPF_RSH, dnp->dn_reg, 32 + 20));
+}
+
+static void
+dt_cg_subr_getminor(dt_node_t *dnp, dt_irlist_t *dlp, dt_regset_t *drp)
+{
+	dt_node_t	*arg = dnp->dn_args;
+
+	dt_cg_node(arg, dlp, drp);
+	dnp->dn_reg = arg->dn_reg;
+	emit(dlp, BPF_ALU64_IMM(BPF_AND, dnp->dn_reg, 0xfffff));
+}
+
 /*
  * Get and return a new speculation ID.  These are unallocated entries in the
  * specs map, obtained by calling dt_speculation().  Return zero if none is
@@ -4594,8 +4620,8 @@ static dt_cg_subr_f *_dt_cg_subr[DIF_SUBR_MAX + 1] = {
 	[DIF_SUBR_COPYINTO]		= NULL,
 	[DIF_SUBR_MSGDSIZE]		= NULL,
 	[DIF_SUBR_MSGSIZE]		= NULL,
-	[DIF_SUBR_GETMAJOR]		= NULL,
-	[DIF_SUBR_GETMINOR]		= NULL,
+	[DIF_SUBR_GETMAJOR]		= &dt_cg_subr_getmajor,
+	[DIF_SUBR_GETMINOR]		= &dt_cg_subr_getminor,
 	[DIF_SUBR_DDI_PATHNAME]		= NULL,
 	[DIF_SUBR_STRJOIN]		= dt_cg_subr_strjoin,
 	[DIF_SUBR_LLTOSTR]		= &dt_cg_subr_lltostr,

diff --git a/test/unittest/funcs/tst.getmajor.d b/test/unittest/funcs/tst.getmajor.d
@@ -0,0 +1,19 @@
+/*
+ * Oracle Linux DTrace.
+ * Copyright (c) 2022, Oracle and/or its affiliates. All rights reserved.
+ * Licensed under the Universal Permissive License v 1.0 as shown at
+ * http://oss.oracle.com/licenses/upl.
+ */
+
+#pragma D option quiet
+
+BEGIN
+{
+	printf("%x", getmajor(0xabcdef0123456789ll));
+	exit(0);
+}
+
+ERROR
+{
+	exit(1);
+}
diff --git a/test/unittest/funcs/tst.getmajor.r b/test/unittest/funcs/tst.getmajor.r
@@ -0,0 +1 @@
+234
diff --git a/test/unittest/funcs/tst.getminor.d b/test/unittest/funcs/tst.getminor.d
@@ -0,0 +1,19 @@
+/*
+ * Oracle Linux DTrace.
+ * Copyright (c) 2022, Oracle and/or its affiliates. All rights reserved.
+ * Licensed under the Universal Permissive License v 1.0 as shown at
+ * http://oss.oracle.com/licenses/upl.
+ */
+
+#pragma D option quiet
+
+BEGIN
+{
+	printf("%x", getminor(0xabcdef0123456789ll));
+	exit(0);
+}
+
+ERROR
+{
+	exit(1);
+}
diff --git a/test/unittest/funcs/tst.getminor.r b/test/unittest/funcs/tst.getminor.r
@@ -0,0 +1 @@
+56789