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2017-02-08s390/sclp: move early printk code to driversHeiko Carstens1-213/+0
Move the early sclp printk code to the drivers folder where also the rest of the sclp code can be found. This way it is possible to use the sclp private header files for further cleanups. Reviewed-by: Peter Oberparleiter <oberpar@linux.vnet.ibm.com> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2017-01-16s390: provide sclp based boot consoleHeiko Carstens1-9/+16
Use the early sclp code to provide a boot console. This boot console is available if the kernel parameter "earlyprintk" has been specified, just like it works for other architectures that also provide an early boot console. This makes debugging of early problems much easier, since now we finally have working console output even before memory detection is running. The boot console will be automatically disabled as soon as another console will be registered. Reviewed-by: Peter Oberparleiter <oberpar@linux.vnet.ibm.com> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2017-01-16s390/sclp: always stay within bounds of the early sccbHeiko Carstens1-1/+6
Make sure the _sclp_print_lm function stays within bounds of the early sccb, even if the passed string is very long. If the string is too long, the remaining characters will be dropped. Suggested-by: Peter Oberparleiter <oberpar@linux.vnet.ibm.com> Reviewed-by: Peter Oberparleiter <oberpar@linux.vnet.ibm.com> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2017-01-16s390/sclp: make early sclp irq handler more robustHeiko Carstens1-5/+10
Make the early sclp interrupt handler more robust: - disable all interrupt sub classes except for the service signal subclass - extend ctlreg0 union so it is easily possible to set the service signal subclass mask bit without using a magic number - disable lowcore protection before writing to it - make sure that all write accesses are done before the original content of control register 0 is restored, which could enable lowcore protection Reviewed-by: Peter Oberparleiter <oberpar@linux.vnet.ibm.com> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2016-07-31s390/sclp: move uninitialized data to data sectionHeiko Carstens1-2/+3
The early sclp code may be called before the bss section is cleared. Therefore move all variables to the data section. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2015-11-27s390/sclp: Add VT220 support to early sclp consoleSascha Silbe1-15/+50
When running under qemu with the default configuration (-nographic), there is only a VT220 SCLP console, no line-mode SCLP console. Add VT220 support to the early SCLP console so the user has a chance to see critical error messages during early boot. None of the existing users of _sclp_print_early() check the return code. Instead of trying to come up with return code semantics when printing to multiple consoles (any or all of which may fail), we just drop the return code entirely. Tested on z/VM (line mode console) and LPAR (VT220 and line mode console). Tested on qemu/KVM with VT220 console and / or line mode console. Signed-off-by: Sascha Silbe <silbe@linux.vnet.ibm.com> Reviewed-by: Peter Oberparleiter <oberpar@linux.vnet.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2015-11-12s390/sclp: _sclp_wait_int(): retain full PSW maskSascha Silbe1-1/+1
There's no reason to clear all PSW mask bits other than the addressing mode bits. Just use the previous PSW mask as-is. Signed-off-by: Sascha Silbe <silbe@linux.vnet.ibm.com> Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2015-07-29s390/sclp: convert early sclp console code to CMartin Schwidefsky1-0/+160
The 31-bit assembler code for the early sclp console is error prone as git commit fde24b54d976cc123506695c17db01438a11b673 "s390/sclp: clear upper register halves in _sclp_print_early" has shown. Convert the assembler code to C. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>