On 09/02/2021 15.38, Claudio Imbrenda wrote:
Simple EDAT test.
Signed-off-by: Claudio Imbrenda <imbrenda@xxxxxxxxxxxxx>
---
s390x/Makefile | 1 +
s390x/edat.c | 238 ++++++++++++++++++++++++++++++++++++++++++++
s390x/unittests.cfg | 3 +
3 files changed, 242 insertions(+)
create mode 100644 s390x/edat.c
diff --git a/s390x/Makefile b/s390x/Makefile
index 08d85c9f..fc885150 100644
--- a/s390x/Makefile
+++ b/s390x/Makefile
@@ -20,6 +20,7 @@ tests += $(TEST_DIR)/sclp.elf
tests += $(TEST_DIR)/css.elf
tests += $(TEST_DIR)/uv-guest.elf
tests += $(TEST_DIR)/sie.elf
+tests += $(TEST_DIR)/edat.elf
tests_binary = $(patsubst %.elf,%.bin,$(tests))
ifneq ($(HOST_KEY_DOCUMENT),)
diff --git a/s390x/edat.c b/s390x/edat.c
new file mode 100644
index 00000000..504a1501
--- /dev/null
+++ b/s390x/edat.c
@@ -0,0 +1,238 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * EDAT test.
+ *
+ * Copyright (c) 2021 IBM Corp
+ *
+ * Authors:
+ * Claudio Imbrenda <imbrenda@xxxxxxxxxxxxx>
+ */
+#include <libcflat.h>
+#include <vmalloc.h>
+#include <asm/facility.h>
+#include <asm/interrupt.h>
+#include <mmu.h>
+#include <asm/pgtable.h>
+#include <asm-generic/barrier.h>
+
+#define TEID_ADDR PAGE_MASK
+#define TEID_AI 0x003
+#define TEID_M 0x004
+#define TEID_A 0x008
+#define TEID_FS 0xc00
+
+#define LC_SIZE (2 * PAGE_SIZE)
+#define VIRT(x) ((void *)((unsigned long)(x) + (unsigned long)mem))
+
+static uint8_t prefix_buf[LC_SIZE] __attribute__((aligned(LC_SIZE)));
+static unsigned int tmp[1024] __attribute__((aligned(PAGE_SIZE)));
+static void *root, *mem, *m;
+static struct lowcore *lc;
+volatile unsigned int *p;
+
+/* Expect a program interrupt, and clear the TEID */
+static void expect_dat_fault(void)
+{
+ expect_pgm_int();
+ lc->trans_exc_id = 0;
+}
+
+/* Check if a protection exception happened for the given address */
+static bool check_pgm_prot(void *ptr)
+{
+ unsigned long teid = lc->trans_exc_id;
+
+ if (lc->pgm_int_code != PGM_INT_CODE_PROTECTION)
+ return 0;
return false.
It's a bool return type.
+ if (~teid & TEID_M)
I'd maybe rather write this as:
if (!(teid & TEID_M))
... but it's just a matter of taste.
+ return 1;
return true;
So this is for backward compatiblity with older Z systems that do not have
the corresponding facility? Should there be a corresponding facility check
somewhere? Or maybe add at least a comment?
+ return (~teid & TEID_A) &&
+ ((teid & TEID_ADDR) == ((uint64_t)ptr & PAGE_MASK)) &&
+ !(teid & TEID_AI);
So you're checking for one specific type of protection exception here only
... please add an appropriate comment.
+}
+
+static void test_dat(void)
+{
+ report_prefix_push("edat off");
+ /* disable EDAT */
+ ctl_clear_bit(0, 23);
+
+ /* Check some basics */
+ p[0] = 42;
+ report(p[0] == 42, "pte, r/w");
+ p[0] = 0;
+
+ protect_page(m, PAGE_ENTRY_P);
+ expect_dat_fault();
+ p[0] = 42;
+ unprotect_page(m, PAGE_ENTRY_P);
+ report(!p[0] && check_pgm_prot(m), "pte, ro");
+
+ /* The FC bit should be ignored because EDAT is off */
+ p[0] = 42;
I'd suggest to set p[0] = 0 here...
+ protect_dat_entry(m, SEGMENT_ENTRY_FC, 4);
... and change the value to 42 after enabling the protection ... otherwise
you don't really test the non-working write protection here, do you?
+ report(p[0] == 42, "pmd, fc=1, r/w");
+ unprotect_dat_entry(m, SEGMENT_ENTRY_FC, 4);
+ p[0] = 0;
+
+ /* Segment protection should work even with EDAT off */
+ protect_dat_entry(m, SEGMENT_ENTRY_P, 4);
+ expect_dat_fault();
+ p[0] = 42;
+ report(!p[0] && check_pgm_prot(m), "pmd, ro");
+ unprotect_dat_entry(m, SEGMENT_ENTRY_P, 4);
+
+ /* The FC bit should be ignored because EDAT is off*/
Set p[0] to 0 again before enabling the protection? Or maybe use a different
value than 42 below...?
+ protect_dat_entry(m, REGION3_ENTRY_FC, 3);
+ p[0] = 42;
+ report(p[0] == 42, "pud, fc=1, r/w");
+ unprotect_dat_entry(m, REGION3_ENTRY_FC, 3);
+ p[0] = 0;
+
+ /* Region1/2/3 protection should not work, because EDAT is off */
+ protect_dat_entry(m, REGION_ENTRY_P, 3);
+ p[0] = 42;
+ report(p[0] == 42, "pud, ro");
+ unprotect_dat_entry(m, REGION_ENTRY_P, 3);
+ p[0] = 0;
+
+ protect_dat_entry(m, REGION_ENTRY_P, 2);
+ p[0] = 42;
+ report(p[0] == 42, "p4d, ro");
+ unprotect_dat_entry(m, REGION_ENTRY_P, 2);
+ p[0] = 0;
+
+ protect_dat_entry(m, REGION_ENTRY_P, 1);
+ p[0] = 42;
+ report(p[0] == 42, "pgd, ro");
+ unprotect_dat_entry(m, REGION_ENTRY_P, 1);
+ p[0] = 0;
+
+ report_prefix_pop();
+}
Thomas
