kernel/arch/s390/include/asm/ap.h, branch linux-5.14.y

s390/ap: get rid of register asm in ap_dqap()

2021-07-08T20:12:17Z

This is the second part of the cleanup for the header file ap.h to remove the register asm statements. This patch deals with the inline ap_dqap() function where within the assembler code an odd register of an register pair is to be addressed. [hca@linux.ibm.com: this intentionally breaks compilation with any clang compilers prior to llvm-project commit 458eac257377 ("[SystemZ] Support the 'N' code for the odd register in inline-asm."). This is hopefully the last clang kernel compile breakage caused by incompatibilities between gcc and clang.] Signed-off-by: Harald Freudenberger Signed-off-by: Heiko Carstens Signed-off-by: Vasily Gorbik

s390/ap: get rid of register asm

2021-07-08T13:37:27Z

Using register asm statements has been proven to be very error prone, especially when using code instrumentation where gcc may add function calls, which clobbers register contents in an unexpected way. Therefore get rid of register asm statements in ap code. There are also potential bugs, depending on inline decisions of the compiler. E.g. for: static inline struct ap_queue_status ap_tapq(ap_qid_t qid, unsigned long *info) { register unsigned long reg0 asm ("0") = qid; register struct ap_queue_status reg1 asm ("1"); register unsigned long reg2 asm ("2"); asm volatile(".long 0xb2af0000" /* PQAP(TAPQ) */ : "=d" (reg1), "=d" (reg2) : "d" (reg0) : "cc"); if (info) *info = reg2; return reg1; } In case of KCOV the "if (info)" line could cause a generated function call, which could clobber the contents of both reg2, and reg1. Similar can happen in case of KASAN for the "*info = reg2" line. Even though compilers will likely inline the function and optimize things away, this is not guaranteed. To get rid of this bug class, simply get rid of register asm constructs. Note: The inline function ap_dqap() will be handled in a separate patch because this one requires an addressing of the odd register of a register pair (which is done with %N[xxx] in the assembler code) and that's currently not supported by clang. Signed-off-by: Heiko Carstens Signed-off-by: Harald Freudenberger Signed-off-by: Vasily Gorbik

s390/ap: Rework ap_dqap to deal with messages greater than recv buffer

2021-07-08T13:37:27Z

Rework of the ap_dqap() inline function with the dqap inline assembler invocation and the caller code in ap_queue.c to be able to handle replies which exceed the receive buffer size. ap_dqap() now provides two additional parameters to handle together with the caller the case where a reply in the firmware queue entry exceeds the given message buffer size. It depends on the caller how to exactly handle this. The behavior implemented now by ap_sm_recv() in ap_queue.c is to simple purge this entry from the firmware queue and let the caller 'receive' a -EMSGSIZE for the request without delivering any reply data - not even a truncated reply message. However, the reworked ap_dqap() could now get invoked in a way that the message is received in multiple parts and the caller assembles the parts into one reply message. Signed-off-by: Harald Freudenberger Suggested-by: Juergen Christ Reviewed-by: Juergen Christ Signed-off-by: Vasily Gorbik

s390/ap: remove unneeded semicolon

2021-02-09T14:57:04Z

Remove a superfluous semicolon after function definition. Signed-off-by: Chengyang Fan Message-Id: <20210125095839.1720265-1-cy.fan@huawei.com> Signed-off-by: Vasily Gorbik

s390/zcrypt: Fix wrong dispatching for control domain CPRBs

2019-05-28T12:49:38Z

The zcrypt device driver does not handle CPRBs which address a control domain correctly. This fix introduces a workaround: The domain field of the request CPRB is checked if there is a valid domain value in there. If this is true and the value is a control only domain (a domain which is enabled in the crypto config ADM mask but disabled in the AQM mask) the CPRB is forwarded to the default usage domain. If there is no default domain, the request is rejected with an ENODEV. This fix is important for maintaining crypto adapters. For example one LPAR can use a crypto adapter domain ('Control and Usage') but another LPAR needs to be able to maintain this adapter domain ('Control'). Scenarios like this did not work properly and the patch enables this. Signed-off-by: Harald Freudenberger Signed-off-by: Heiko Carstens

zcrypt: handle AP Info notification from CHSC SEI command

2019-03-11T17:16:42Z

The current AP bus implementation periodically polls the AP configuration to detect changes. When the AP configuration is dynamically changed via the SE or an SCLP instruction, the changes will not be reflected to sysfs until the next time the AP configuration is polled. The CHSC architecture provides a Store Event Information (SEI) command to make notification of an AP configuration change. This patch introduces a handler to process notification from the CHSC SEI command by immediately kicking off an AP bus scan-after-event. Signed-off-by: Tony Krowiak Reviewed-by: Halil Pasic Reviewed-by: Sebastian Ott Reviewed-by: Harald Freudenberger Reviewed-by: Cornelia Huck Signed-off-by: Sebastian Ott Signed-off-by: Martin Schwidefsky

s390/ap: rework assembler functions to use unions for in/out register variables

2018-11-30T06:22:05Z

The inline assembler functions ap_aqic() and ap_qact() used two variables declared on the very same register. One variable was for input only, the other for output. Looks like newer versions of the gcc don't like this. Anyway it is a better coding to use one variable (which may have a union data type) on one register for input and output. So this patch introduces unions and uses only one variable now for input and output for GR1 for the PQAP(QACT) and PQAP(QIC) invocation. Signed-off-by: Harald Freudenberger Acked-by: Ilya Leoshkevich Signed-off-by: Martin Schwidefsky

s390/zcrypt: switch return type to bool for ap_instructions_available()

2018-08-20T14:02:10Z

Function ap_instructions_available() had returntype int but in fact returned 1 for true and 0 for false. Changed returntype to bool. Signed-off-by: Harald Freudenberger Signed-off-by: Martin Schwidefsky

s390/zcrypt: fix ap_instructions_available() returncodes

2018-08-16T12:49:11Z

During review of KVM patches it was complained that the ap_instructions_available() function returns 0 if AP instructions are available and -ENODEV if not. The function acts like a boolean function to check for AP instructions available and thus should return 0 on failure and != 0 on success. Changed to the suggested behaviour and adapted the one and only caller of this function which is the ap bus core code. Signed-off-by: Harald Freudenberger Acked-by: Cornelia Huck Signed-off-by: Heiko Carstens

s390/zcrypt: Integrate ap_asm.h into include/asm/ap.h.

2018-06-25T08:21:18Z

Move all the inline functions from the ap bus header file ap_asm.h into the in-kernel api header file arch/s390/include/asm/ap.h so that KVM can make use of all the low level AP functions. Signed-off-by: Harald Freudenberger Signed-off-by: Martin Schwidefsky