subr_physmem_test: add tests for two edge-cases

Help validate my assertion that "physmem will never report empty
ranges". Part of this is covered by the existing tests, which check the
merging of adjacent/overlapping regions. The other part is to ensure
that addition of zero-sized ranges is ignored.

The physmem implementation also includes logic to ignore the first
physical page of memory (physical addresses 0 to PAGE_SIZE-1). Add a
second test case for this.

Reviewed by:	markj
MFC after:	1 week
Differential Revision:	https://reviews.freebsd.org/D45914

1 files changed, 43 insertions, 0 deletions

diff --git a/tests/sys/kern/subr_physmem_test.c b/tests/sys/kern/subr_physmem_test.c
index 31bd30447e3b..96e608a36d72 100644
--- a/tests/sys/kern/subr_physmem_test.c
+++ b/tests/sys/kern/subr_physmem_test.c
@@ -160,11 +160,54 @@ ATF_TC_BODY(hwregion_unordered, tc)
 	ATF_CHECK_EQ(avail[1], 3 * PAGE_SIZE);
 }
 
+ATF_TC_WITHOUT_HEAD(hwregion_ignore_empty);
+ATF_TC_BODY(hwregion_ignore_empty, tc)
+{
+	vm_paddr_t avail[4];
+	size_t len;
+
+	/* Add a region. */
+	physmem_hardware_region(PAGE_SIZE, 2 * PAGE_SIZE);
+
+	/* Add full zero range (ignored) */
+	physmem_hardware_region(0, 0);
+
+	/* Add a zero-sized range (ignored) */
+	physmem_hardware_region(4 * PAGE_SIZE, 0);
+
+	len = physmem_avail(avail, nitems(avail));
+	ATF_CHECK_EQ(len, 2);
+	ATF_CHECK_EQ(avail[0], PAGE_SIZE);
+	ATF_CHECK_EQ(avail[1], 3 * PAGE_SIZE);
+}
+
+ATF_TC_WITHOUT_HEAD(hwregion_ignore_page0);
+ATF_TC_BODY(hwregion_ignore_page0, tc)
+{
+	vm_paddr_t avail[4];
+	size_t len;
+
+	/*
+	 * Physical addresses [0, PAGE_SIZE) are unusable in the VM layer.
+	 *
+	 * physmem will truncate this from the beginning of an otherwise valid
+	 * memory range; test that this is the case.
+	 */
+	physmem_hardware_region(0, 2 * PAGE_SIZE);
+
+	len = physmem_avail(avail, 4);
+	ATF_CHECK_EQ(len, 2);
+	ATF_CHECK_EQ(avail[0], PAGE_SIZE);
+	ATF_CHECK_EQ(avail[1], 2 * PAGE_SIZE);
+}
+
 ATF_TP_ADD_TCS(tp)
 {
 
 	ATF_TP_ADD_TC(tp, hwregion);
 	ATF_TP_ADD_TC(tp, hwregion_exclude);
 	ATF_TP_ADD_TC(tp, hwregion_unordered);
+	ATF_TP_ADD_TC(tp, hwregion_ignore_empty);
+	ATF_TP_ADD_TC(tp, hwregion_ignore_page0);
 	return (atf_no_error());
 }