On 8/20/21 1:48 PM, Claudio Imbrenda wrote:
> On Fri, 20 Aug 2021 11:39:58 +0000
> Janosch Frank <frankja@xxxxxxxxxxxxx> wrote:
>
>> 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@xxxxxxxxxxxxx>
>
> Reviewed-by: Claudio Imbrenda <imbrenda@xxxxxxxxxxxxx>
Thanks
>
> (but see a small nit below)
>
>> ---
>> lib/s390x/asm/arch_def.h | 5 +++
>> lib/s390x/fault.c | 76 ++++++++++++++++++++++++++++++++++++++++
>> lib/s390x/fault.h | 44 +++++++++++++++++++++++
>> lib/s390x/interrupt.c | 29 +++++++++++++--
>> s390x/Makefile | 1 +
>> 5 files changed, 153 insertions(+), 2 deletions(-)
>> create mode 100644 lib/s390x/fault.c
>> create mode 100644 lib/s390x/fault.h
>>
>> diff --git a/lib/s390x/asm/arch_def.h b/lib/s390x/asm/arch_def.h
>> index 302ef1ff..ab5a9043 100644
>> --- a/lib/s390x/asm/arch_def.h
>> +++ b/lib/s390x/asm/arch_def.h
>> @@ -41,6 +41,11 @@ struct psw {
>> uint64_t addr;
>> };
>>
>> +#define AS_PRIM 0
>> +#define AS_ACCR 1
>> +#define AS_SECN 2
>> +#define AS_HOME 3
>> +
>> #define PSW_MASK_EXT 0x0100000000000000UL
>> #define PSW_MASK_IO 0x0200000000000000UL
>> #define PSW_MASK_DAT 0x0400000000000000UL
>> diff --git a/lib/s390x/fault.c b/lib/s390x/fault.c
>> new file mode 100644
>> index 00000000..fd1490e3
>> --- /dev/null
>> +++ b/lib/s390x/fault.c
>> @@ -0,0 +1,76 @@
>> +/* SPDX-License-Identifier: GPL-2.0-only */
>> +/*
>> + * Library to decode addressing related exceptions
>> + *
>> + * Copyright 2021 IBM Corp.
>> + *
>> + * Authors:
>> + * Janosch Frank <frankja@xxxxxxxxxxxxx>
>> + */
>> +#include <libcflat.h>
>> +#include <bitops.h>
>> +#include <asm/arch_def.h>
>> +#include <asm/page.h>
>> +#include <fault.h>
>> +
>> +static struct lowcore *lc = (struct lowcore *)0x0;
>> +
>> +/* Decodes the protection exceptions we'll most likely see */
>> +static void decode_pgm_prot(uint64_t teid)
>
> I think this is also a "print_decode_pgm_prot", but it's static
> so I guess we don't really care too much
Can do, sounds reasonable
>
>> +{
>> + if (prot_is_lap(teid)) {
>> + printf("Type: LAP\n");
>> + return;
>> + }
>> +
>> + if (prot_is_iep(teid)) {
>> + printf("Type: IEP\n");
>> + return;
>> + }
>> +
>> + if (prot_is_datp(teid)) {
>> + printf("Type: DAT\n");
>> + return;
>> + }
>> +}
>> +
>> +void print_decode_teid(uint64_t teid)
>> +{
>> + int asce_id = teid & 3;
>> + bool dat = lc->pgm_old_psw.mask & PSW_MASK_DAT;
>> +
>> + printf("Memory exception information:\n");
>> + printf("DAT: %s\n", dat ? "on" : "off");
>> +
>> + printf("AS: ");
>> + switch (asce_id) {
>> + case AS_PRIM:
>> + printf("Primary\n");
>> + break;
>> + case AS_ACCR:
>> + printf("Access Register\n");
>> + break;
>> + case AS_SECN:
>> + printf("Secondary\n");
>> + break;
>> + case AS_HOME:
>> + printf("Home\n");
>> + break;
>> + }
>> +
>> + 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("TEID: %lx\n", teid);
>> + printf("Address: %lx\n\n", teid & PAGE_MASK);
>> +}
>> diff --git a/lib/s390x/fault.h b/lib/s390x/fault.h
>> new file mode 100644
>> index 00000000..726da2f0
>> --- /dev/null
>> +++ b/lib/s390x/fault.h
>> @@ -0,0 +1,44 @@
>> +/* SPDX-License-Identifier: GPL-2.0-or-later */
>> +/*
>> + * Headers for fault.c
>> + *
>> + * Copyright 2021 IBM Corp.
>> + *
>> + * Authors:
>> + * Janosch Frank <frankja@xxxxxxxxxxxxx>
>> + */
>> +#ifndef _S390X_FAULT_H_
>> +#define _S390X_FAULT_H_
>> +
>> +#include <bitops.h>
>> +
>> +/* Instruction execution prevention, i.e. no-execute, 101 */
>> +static inline bool prot_is_iep(uint64_t 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;
>> +}
>> +
>> +void print_decode_teid(uint64_t teid);
>> +
>> +#endif /* _S390X_FAULT_H_ */
>> diff --git a/lib/s390x/interrupt.c b/lib/s390x/interrupt.c
>> index 01ded49d..721e6758 100644
>> --- a/lib/s390x/interrupt.c
>> +++ b/lib/s390x/interrupt.c
>> @@ -12,6 +12,8 @@
>> #include <sclp.h>
>> #include <interrupt.h>
>> #include <sie.h>
>> +#include <fault.h>
>> +#include <asm/page.h>
>>
>> static bool pgm_int_expected;
>> static bool ext_int_expected;
>> @@ -76,8 +78,7 @@ static void fixup_pgm_int(struct stack_frame_int *stack)
>> break;
>> case PGM_INT_CODE_PROTECTION:
>> /* Handling for iep.c test case. */
>> - if (lc->trans_exc_id & 0x80UL && lc->trans_exc_id & 0x04UL &&
>> - !(lc->trans_exc_id & 0x08UL))
>> + if (prot_is_iep(lc->trans_exc_id))
>> /*
>> * We branched to the instruction that caused
>> * the exception so we can use the return
>> @@ -126,6 +127,26 @@ static void fixup_pgm_int(struct stack_frame_int *stack)
>> /* suppressed/terminated/completed point already at the next address */
>> }
>>
>> +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:
>> + print_decode_teid(lc->trans_exc_id);
>> + break;
>> + default:
>> + return;
>> + }
>> +}
>> +
>> static void print_int_regs(struct stack_frame_int *stack)
>> {
>> printf("\n");
>> @@ -155,6 +176,10 @@ 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();
>> }
>> diff --git a/s390x/Makefile b/s390x/Makefile
>> index ef8041a6..5d1a33a0 100644
>> --- a/s390x/Makefile
>> +++ b/s390x/Makefile
>> @@ -72,6 +72,7 @@ cflatobjs += lib/s390x/css_lib.o
>> cflatobjs += lib/s390x/malloc_io.o
>> cflatobjs += lib/s390x/uv.o
>> cflatobjs += lib/s390x/sie.o
>> +cflatobjs += lib/s390x/fault.o
>>
>> OBJDIRS += lib/s390x
>>
>
