[kvm-unit-tests PATCH 3/8] lib: s390x: Print addressing related exception information

[Janosch Frank <frankja@linux.ibm.com>]

Right now we only get told the kind of program exception as well as
the PSW at the point where it happened.

For addressing exceptions the PSW is not always enough so let's print
the TEID which contains the failing address and flags that tell us
more about the kind of address exception.

Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
---
 lib/s390x/asm/arch_def.h |  4 +++
 lib/s390x/interrupt.c    | 72 ++++++++++++++++++++++++++++++++++++++++
 2 files changed, 76 insertions(+)

diff --git a/lib/s390x/asm/arch_def.h b/lib/s390x/asm/arch_def.h
index 4ca02c1d..39c5ba99 100644
--- a/lib/s390x/asm/arch_def.h
+++ b/lib/s390x/asm/arch_def.h
@@ -41,6 +41,10 @@ struct psw {
 	uint64_t	addr;
 };
 
+/* Let's ignore spaces we don't expect to use for now. */
+#define AS_PRIM				0
+#define AS_HOME				3
+
 #define PSW_MASK_EXT			0x0100000000000000UL
 #define PSW_MASK_IO			0x0200000000000000UL
 #define PSW_MASK_DAT			0x0400000000000000UL
diff --git a/lib/s390x/interrupt.c b/lib/s390x/interrupt.c
index 01ded49d..1248bceb 100644
--- a/lib/s390x/interrupt.c
+++ b/lib/s390x/interrupt.c
@@ -12,6 +12,7 @@
 #include <sclp.h>
 #include <interrupt.h>
 #include <sie.h>
+#include <asm/page.h>
 
 static bool pgm_int_expected;
 static bool ext_int_expected;
@@ -126,6 +127,73 @@ static void fixup_pgm_int(struct stack_frame_int *stack)
 	/* suppressed/terminated/completed point already at the next address */
 }
 
+static void decode_pgm_prot(uint64_t teid)
+{
+	/* Low-address protection exception, 100 */
+	if (test_bit_inv(56, &teid) && !test_bit_inv(60, &teid) && !test_bit_inv(61, &teid)) {
+		printf("Type: LAP\n");
+		return;
+	}
+
+	/* Instruction execution prevention, i.e. no-execute, 101 */
+	if (test_bit_inv(56, &teid) && !test_bit_inv(60, &teid) && test_bit_inv(61, &teid)) {
+		printf("Type: IEP\n");
+		return;
+	}
+
+	/* Standard DAT exception, 001 */
+	if (!test_bit_inv(56, &teid) && !test_bit_inv(60, &teid) && test_bit_inv(61, &teid)) {
+		printf("Type: DAT\n");
+		return;
+	}
+}
+
+static void decode_teid(uint64_t teid)
+{
+	int asce_id = lc->trans_exc_id & 3;
+	bool dat = lc->pgm_old_psw.mask & PSW_MASK_DAT;
+
+	printf("Memory exception information:\n");
+	printf("TEID: %lx\n", teid);
+	printf("DAT: %s\n", dat ? "on" : "off");
+	printf("AS: %s\n", asce_id == AS_PRIM ? "Primary" : "Home");
+
+	if (lc->pgm_int_code == PGM_INT_CODE_PROTECTION)
+		decode_pgm_prot(teid);
+
+	/*
+	 * If teid bit 61 is off for these two exception the reported
+	 * address is unpredictable.
+	 */
+	if ((lc->pgm_int_code == PGM_INT_CODE_SECURE_STOR_ACCESS ||
+	     lc->pgm_int_code == PGM_INT_CODE_SECURE_STOR_VIOLATION) &&
+	    !test_bit_inv(61, &teid)) {
+		printf("Address: %lx, unpredictable\n ", teid & PAGE_MASK);
+		return;
+	}
+	printf("Address: %lx\n\n", teid & PAGE_MASK);
+}
+
+static void print_storage_exception_information(void)
+{
+	switch (lc->pgm_int_code) {
+	case PGM_INT_CODE_PROTECTION:
+	case PGM_INT_CODE_PAGE_TRANSLATION:
+	case PGM_INT_CODE_SEGMENT_TRANSLATION:
+	case PGM_INT_CODE_ASCE_TYPE:
+	case PGM_INT_CODE_REGION_FIRST_TRANS:
+	case PGM_INT_CODE_REGION_SECOND_TRANS:
+	case PGM_INT_CODE_REGION_THIRD_TRANS:
+	case PGM_INT_CODE_SECURE_STOR_ACCESS:
+	case PGM_INT_CODE_NON_SECURE_STOR_ACCESS:
+	case PGM_INT_CODE_SECURE_STOR_VIOLATION:
+		decode_teid(lc->trans_exc_id);
+		break;
+	default:
+		return;
+	}
+}
+
 static void print_int_regs(struct stack_frame_int *stack)
 {
 	printf("\n");
@@ -155,6 +223,10 @@ static void print_pgm_info(struct stack_frame_int *stack)
 	       lc->pgm_int_code, stap(), lc->pgm_old_psw.addr, lc->pgm_int_id);
 	print_int_regs(stack);
 	dump_stack();
+
+	/* Dump stack doesn't end with a \n so we add it here instead */
+	printf("\n");
+	print_storage_exception_information();
 	report_summary();
 	abort();
 }
-- 
2.30.2