From e443ef9f21acdc6459b3fbad04019a40ea8c4e80 Mon Sep 17 00:00:00 2001 From: Halil Pasic Date: Tue, 17 Oct 2017 16:04:48 +0200 Subject: [PATCH] s390x/css: IO instr handler ending control CSS code needs to tell the IO instruction handlers located in ioinst.c how the emulated instruction should be ended. Currently this is done by returning generic (POSIX) error codes, and mapping them to outcomes like condition codes. This makes bugs easy to create and hard to recognize. As a preparation for moving away from (mis)using generic error codes for flow control let us introduce a type which tells the instruction handler function how to end the instruction, in a more straight-forward and less ambiguous way. Signed-off-by: Halil Pasic Message-Id: <20171017140453.51099-3-pasic@linux.vnet.ibm.com> Reviewed-by: Thomas Huth Reviewed-by: Dong Jia Shi [CH: cosmetic changes] Signed-off-by: Cornelia Huck --- include/hw/s390x/css.h | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) diff --git a/include/hw/s390x/css.h b/include/hw/s390x/css.h index 69b374730e..08ad1a14cf 100644 --- a/include/hw/s390x/css.h +++ b/include/hw/s390x/css.h @@ -99,6 +99,22 @@ typedef struct CcwDataStream { hwaddr cda; } CcwDataStream; +/* + * IO instructions conclude according to this. Currently we have only + * cc codes. Valid values are 0, 1, 2, 3 and the generic semantic for + * IO instructions is described briefly. For more details consult the PoP. + */ +typedef enum IOInstEnding { + /* produced expected result */ + IOINST_CC_EXPECTED = 0, + /* status conditions were present or produced alternate result */ + IOINST_CC_STATUS_PRESENT = 1, + /* inst. ineffective because busy with previously initiated function */ + IOINST_CC_BUSY = 2, + /* inst. ineffective because not operational */ + IOINST_CC_NOT_OPERATIONAL = 3 +} IOInstEnding; + typedef struct SubchDev SubchDev; struct SubchDev { /* channel-subsystem related things: */ -- 2.11.4.GIT