[kvm-unit-tests GIT PULL 03/12] s390x: Rework TEID decoding and usage

[Claudio Imbrenda <imbrenda@linux.ibm.com>]

From: Janis Schoetterl-Glausch <scgl@linux.ibm.com>

The translation-exception identification (TEID) contains information to
identify the cause of certain program exceptions, including translation
exceptions occurring during dynamic address translation, as well as
protection exceptions.
The meaning of fields in the TEID is complex, depending on the exception
occurring and various potentially installed facilities.

Rework the type describing the TEID, in order to ease decoding.
Change the existing code interpreting the TEID and extend it to take the
installed suppression-on-protection facility into account.

Signed-off-by: Janis Schoetterl-Glausch <scgl@linux.ibm.com>
Message-Id: <20220621143015.748290-4-scgl@linux.ibm.com>
Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
---
 lib/s390x/asm/interrupt.h | 62 ++++++++++++++++++++++++++++++---------
 lib/s390x/fault.h         | 30 +++++--------------
 lib/s390x/fault.c         | 58 +++++++++++++++++++++++-------------
 lib/s390x/interrupt.c     |  2 +-
 s390x/edat.c              | 25 +++++++++-------
 5 files changed, 108 insertions(+), 69 deletions(-)

diff --git a/lib/s390x/asm/interrupt.h b/lib/s390x/asm/interrupt.h
index d9ab0bd7..fc66a925 100644
--- a/lib/s390x/asm/interrupt.h
+++ b/lib/s390x/asm/interrupt.h
@@ -20,23 +20,57 @@
 
 union teid {
 	unsigned long val;
-	struct {
-		unsigned long addr:52;
-		unsigned long fetch:1;
-		unsigned long store:1;
-		unsigned long reserved:6;
-		unsigned long acc_list_prot:1;
-		/*
-		 * depending on the exception and the installed facilities,
-		 * the m field can indicate several different things,
-		 * including whether the exception was triggered by a MVPG
-		 * instruction, or whether the addr field is meaningful
-		 */
-		unsigned long m:1;
-		unsigned long asce_id:2;
+	union {
+		/* common fields DAT exc & protection exc */
+		struct {
+			uint64_t addr			: 52 -  0;
+			uint64_t acc_exc_fetch_store	: 54 - 52;
+			uint64_t side_effect_acc	: 55 - 54;
+			uint64_t /* reserved */		: 62 - 55;
+			uint64_t asce_id		: 64 - 62;
+		};
+		/* DAT exc */
+		struct {
+			uint64_t /* pad */		: 61 -  0;
+			uint64_t dat_move_page		: 62 - 61;
+		};
+		/* suppression on protection */
+		struct {
+			uint64_t /* pad */		: 60 -  0;
+			uint64_t sop_acc_list		: 61 - 60;
+			uint64_t sop_teid_predictable	: 62 - 61;
+		};
+		/* enhanced suppression on protection 2 */
+		struct {
+			uint64_t /* pad */		: 56 -  0;
+			uint64_t esop2_prot_code_0	: 57 - 56;
+			uint64_t /* pad */		: 60 - 57;
+			uint64_t esop2_prot_code_1	: 61 - 60;
+			uint64_t esop2_prot_code_2	: 62 - 61;
+		};
 	};
 };
 
+enum prot_code {
+	PROT_KEY_OR_LAP,
+	PROT_DAT,
+	PROT_KEY,
+	PROT_ACC_LIST,
+	PROT_LAP,
+	PROT_IEP,
+	PROT_NUM_CODES /* Must always be last */
+};
+
+static inline enum prot_code teid_esop2_prot_code(union teid teid)
+{
+	int code = (teid.esop2_prot_code_0 << 2 |
+		    teid.esop2_prot_code_1 << 1 |
+		    teid.esop2_prot_code_2);
+
+	assert(code < PROT_NUM_CODES);
+	return (enum prot_code)code;
+}
+
 void register_pgm_cleanup_func(void (*f)(void));
 void handle_pgm_int(struct stack_frame_int *stack);
 void handle_ext_int(struct stack_frame_int *stack);
diff --git a/lib/s390x/fault.h b/lib/s390x/fault.h
index 726da2f0..867997f2 100644
--- a/lib/s390x/fault.h
+++ b/lib/s390x/fault.h
@@ -11,32 +11,16 @@
 #define _S390X_FAULT_H_
 
 #include <bitops.h>
+#include <asm/facility.h>
+#include <asm/interrupt.h>
 
 /* Instruction execution prevention, i.e. no-execute, 101 */
-static inline bool prot_is_iep(uint64_t teid)
+static inline bool prot_is_iep(union teid teid)
 {
-	if (test_bit_inv(56, &teid) && !test_bit_inv(60, &teid) && test_bit_inv(61, &teid))
-		return true;
-
-	return false;
-}
-
-/* Standard DAT exception, 001 */
-static inline bool prot_is_datp(uint64_t teid)
-{
-	if (!test_bit_inv(56, &teid) && !test_bit_inv(60, &teid) && test_bit_inv(61, &teid))
-		return true;
-
-	return false;
-}
-
-/* Low-address protection exception, 100 */
-static inline bool prot_is_lap(uint64_t teid)
-{
-	if (test_bit_inv(56, &teid) && !test_bit_inv(60, &teid) && !test_bit_inv(61, &teid))
-		return true;
-
-	return false;
+	if (!test_facility(130))
+		return false;
+	/* IEP installed -> ESOP2 installed */
+	return teid_esop2_prot_code(teid) == PROT_IEP;
 }
 
 void print_decode_teid(uint64_t teid);
diff --git a/lib/s390x/fault.c b/lib/s390x/fault.c
index efa62fcb..1cd6e265 100644
--- a/lib/s390x/fault.c
+++ b/lib/s390x/fault.c
@@ -13,35 +13,51 @@
 #include <asm/page.h>
 #include <fault.h>
 
-/* Decodes the protection exceptions we'll most likely see */
-static void print_decode_pgm_prot(uint64_t teid)
-{
-	if (prot_is_lap(teid)) {
-		printf("Type: LAP\n");
-		return;
-	}
 
-	if (prot_is_iep(teid)) {
-		printf("Type: IEP\n");
-		return;
-	}
+static void print_decode_pgm_prot(union teid teid)
+{
+	switch (get_supp_on_prot_facility()) {
+	case SOP_NONE:
+	case SOP_BASIC:
+		printf("Type: ?\n"); /* modern/relevant machines have ESOP */
+		break;
+	case SOP_ENHANCED_1:
+		if (teid.sop_teid_predictable) {/* implies access list or DAT */
+			if (teid.sop_acc_list)
+				printf("Type: ACC\n");
+			else
+				printf("Type: DAT\n");
+		} else {
+			printf("Type: KEY or LAP\n");
+		}
+		break;
+	case SOP_ENHANCED_2: {
+		static const char * const prot_str[] = {
+			"KEY or LAP",
+			"DAT",
+			"KEY",
+			"ACC",
+			"LAP",
+			"IEP",
+		};
+		_Static_assert(ARRAY_SIZE(prot_str) == PROT_NUM_CODES);
+		int prot_code = teid_esop2_prot_code(teid);
 
-	if (prot_is_datp(teid)) {
-		printf("Type: DAT\n");
-		return;
+		printf("Type: %s\n", prot_str[prot_code]);
+		}
 	}
 }
 
-void print_decode_teid(uint64_t teid)
+void print_decode_teid(uint64_t raw_teid)
 {
-	int asce_id = teid & 3;
+	union teid teid = { .val = raw_teid };
 	bool dat = lowcore.pgm_old_psw.mask & PSW_MASK_DAT;
 
 	printf("Memory exception information:\n");
 	printf("DAT: %s\n", dat ? "on" : "off");
 
 	printf("AS: ");
-	switch (asce_id) {
+	switch (teid.asce_id) {
 	case AS_PRIM:
 		printf("Primary\n");
 		break;
@@ -65,10 +81,10 @@ void print_decode_teid(uint64_t teid)
 	 */
 	if ((lowcore.pgm_int_code == PGM_INT_CODE_SECURE_STOR_ACCESS ||
 	     lowcore.pgm_int_code == PGM_INT_CODE_SECURE_STOR_VIOLATION) &&
-	    !test_bit_inv(61, &teid)) {
-		printf("Address: %lx, unpredictable\n ", teid & PAGE_MASK);
+	    !teid.sop_teid_predictable) {
+		printf("Address: %lx, unpredictable\n ", raw_teid & PAGE_MASK);
 		return;
 	}
-	printf("TEID: %lx\n", teid);
-	printf("Address: %lx\n\n", teid & PAGE_MASK);
+	printf("TEID: %lx\n", raw_teid);
+	printf("Address: %lx\n\n", raw_teid & PAGE_MASK);
 }
diff --git a/lib/s390x/interrupt.c b/lib/s390x/interrupt.c
index 6da20c44..ac3d1ecd 100644
--- a/lib/s390x/interrupt.c
+++ b/lib/s390x/interrupt.c
@@ -77,7 +77,7 @@ static void fixup_pgm_int(struct stack_frame_int *stack)
 		break;
 	case PGM_INT_CODE_PROTECTION:
 		/* Handling for iep.c test case. */
-		if (prot_is_iep(lowcore.trans_exc_id))
+		if (prot_is_iep((union teid) { .val = lowcore.trans_exc_id }))
 			/*
 			 * We branched to the instruction that caused
 			 * the exception so we can use the return
diff --git a/s390x/edat.c b/s390x/edat.c
index c6c25042..16138397 100644
--- a/s390x/edat.c
+++ b/s390x/edat.c
@@ -26,8 +26,8 @@ static void *root, *mem, *m;
 volatile unsigned int *p;
 
 /*
- * Check if a non-access-list protection exception happened for the given
- * address, in the primary address space.
+ * Check if the exception is consistent with DAT protection and has the correct
+ * address and primary address space.
  */
 static bool check_pgm_prot(void *ptr)
 {
@@ -37,14 +37,19 @@ static bool check_pgm_prot(void *ptr)
 		return false;
 
 	teid.val = lowcore.trans_exc_id;
-
-	/*
-	 * depending on the presence of the ESOP feature, the rest of the
-	 * field might or might not be meaningful when the m field is 0.
-	 */
-	if (!teid.m)
-		return true;
-	return (!teid.acc_list_prot && !teid.asce_id &&
+	switch (get_supp_on_prot_facility()) {
+	case SOP_NONE:
+	case SOP_BASIC:
+		assert(false); /* let's ignore ancient/irrelevant machines */
+	case SOP_ENHANCED_1:
+		if (!teid.sop_teid_predictable) /* implies key or low addr */
+			return false;
+		break;
+	case SOP_ENHANCED_2:
+		if (teid_esop2_prot_code(teid) != PROT_DAT)
+			return false;
+	}
+	return (!teid.sop_acc_list && !teid.asce_id &&
 		(teid.addr == ((unsigned long)ptr >> PAGE_SHIFT)));
 }
 
-- 
2.36.1