Re: [PATCH v1 2/4] s390x: Define the PSW bits

Janosch Frank
2019-11-13T16:07:20Z

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On 11/13/19 1:23 PM, Pierre Morel wrote:
> Instead of assigning obfuscated masks to the PSW dedicated to the
> exceptions, let's define the masks explicitely, it will clarify the

s/explicitely/explicitly/
Try to break that up into sentences.

> usage.
>
> Signed-off-by: Pierre Morel <pmorel@linux.ibm.com>
> ---
> lib/s390x/asm/arch_bits.h | 32 ++++++++++++++++++++++++++++++++
> lib/s390x/asm/arch_def.h | 6 ++----
> s390x/cstart64.S | 13 +++++++------
> 3 files changed, 41 insertions(+), 10 deletions(-)
> create mode 100644 lib/s390x/asm/arch_bits.h
>
> diff --git a/lib/s390x/asm/arch_bits.h b/lib/s390x/asm/arch_bits.h
> new file mode 100644
> index 0000000..0521125
> --- /dev/null
> +++ b/lib/s390x/asm/arch_bits.h
> @@ -0,0 +1,32 @@
> +
> +/*
> + * Copyright (c) 2019 IBM Corp
> + *
> + * Authors:
> + * Pierre Morel <pmorel@linux.ibm.com>
> + *
> + * This code is free software; you can redistribute it and/or modify it
> + * under the terms of the GNU Library General Public License version 2.
> + */
> +#ifndef _ASM_S390X_ARCH_BITS_H_
> +#define _ASM_S390X_ARCH_BITS_H_
> +
> +#define PSW_MASK_PER 0x4000000000000000
> +#define PSW_MASK_DAT 0x0400000000000000
> +#define PSW_MASK_IO 0x0200000000000000
> +#define PSW_MASK_EXT 0x0100000000000000
> +#define PSW_MASK_BASE 0x0000000000000000
> +#define PSW_MASK_KEY 0x00F0000000000000
> +#define PSW_MASK_MCHECK 0x0004000000000000
> +#define PSW_MASK_WAIT 0x0002000000000000
> +#define PSW_MASK_PSTATE 0x0001000000000000
> +#define PSW_MASK_ASC 0x0000C00000000000
> +#define PSW_MASK_CC 0x0000300000000000
> +#define PSW_MASK_PM 0x00000F0000000000
> +#define PSW_MASK_RI 0x0000008000000000
> +#define PSW_MASK_EA 0x0000000100000000
> +#define PSW_MASK_BA 0x0000000080000000

a-f should be lower case in hex values.
Also, do we need all of them?
I'd like to keep it as small as possible.

> +
> +#define PSW_EXCEPTION_MASK (PSW_MASK_EA|PSW_MASK_BA)

That's not a bit anymore, shouldn't that be in arch_def.h?
Also please add a comment, that this is 64 bit addressing.

> +
> +#endif
> diff --git a/lib/s390x/asm/arch_def.h b/lib/s390x/asm/arch_def.h
> index 96cca2e..34c1188 100644
> --- a/lib/s390x/asm/arch_def.h
> +++ b/lib/s390x/asm/arch_def.h
> @@ -10,15 +10,13 @@
> #ifndef _ASM_S390X_ARCH_DEF_H_
> #define _ASM_S390X_ARCH_DEF_H_
>
> +#include <asm/arch_bits.h>
> +
> struct psw {
> uint64_t mask;
> uint64_t addr;
> };
>
> -#define PSW_MASK_EXT 0x0100000000000000UL
> -#define PSW_MASK_DAT 0x0400000000000000UL
> -#define PSW_MASK_PSTATE 0x0001000000000000UL
> -
> #define CR0_EXTM_SCLP 0X0000000000000200UL
> #define CR0_EXTM_EXTC 0X0000000000002000UL
> #define CR0_EXTM_EMGC 0X0000000000004000UL
> diff --git a/s390x/cstart64.S b/s390x/cstart64.S
> index eaff481..7475f32 100644
> --- a/s390x/cstart64.S
> +++ b/s390x/cstart64.S
> @@ -11,6 +11,7 @@
> * under the terms of the GNU Library General Public License version 2.
> */
> #include <asm/asm-offsets.h>
> +#include <asm/arch_bits.h>
> #include <asm/sigp.h>
>
> .section .init
> @@ -196,17 +197,17 @@ svc_int:
>
> .align 8
> initial_psw:
> - .quad 0x0000000180000000, clear_bss_start
> + .quad PSW_EXCEPTION_MASK, clear_bss_start
> pgm_int_psw:
> - .quad 0x0000000180000000, pgm_int
> + .quad PSW_EXCEPTION_MASK, pgm_int
> ext_int_psw:
> - .quad 0x0000000180000000, ext_int
> + .quad PSW_EXCEPTION_MASK, ext_int
> mcck_int_psw:
> - .quad 0x0000000180000000, mcck_int
> + .quad PSW_EXCEPTION_MASK, mcck_int
> io_int_psw:
> - .quad 0x0000000180000000, io_int
> + .quad PSW_EXCEPTION_MASK, io_int
> svc_int_psw:
> - .quad 0x0000000180000000, svc_int
> + .quad PSW_EXCEPTION_MASK, svc_int
> initial_cr0:
> /* enable AFP-register control, so FP regs (+BFP instr) can be used */
> .quad 0x0000000000040000
>

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