Re: [kvm-unit-tests PATCH v3 4/8] s390x: Split assembly and move to s390x/asm/

[Claudio Imbrenda <imbrenda@linux.ibm.com>]

On Fri, 11 Dec 2020 05:00:35 -0500
Janosch Frank <frankja@linux.ibm.com> wrote:

> I've added too much to cstart64.S which is not start related
> already. Now that I want to add even more code it's time to split
> cstart64.S. lib.S has functions that are used in tests. macros.S
> contains macros which are used in cstart64.S and lib.S
> 
> Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
> ---
>  s390x/Makefile             |   8 +--
>  s390x/{ => asm}/cstart64.S | 119
> ++----------------------------------- s390x/asm/lib.S            |
> 65 ++++++++++++++++++++ s390x/asm/macros.S         |  77
> ++++++++++++++++++++++++ 4 files changed, 150 insertions(+), 119
> deletions(-) rename s390x/{ => asm}/cstart64.S (50%)
>  create mode 100644 s390x/asm/lib.S
>  create mode 100644 s390x/asm/macros.S 

[...]

> diff --git a/s390x/cstart64.S b/s390x/asm/cstart64.S
> similarity index 50%
> rename from s390x/cstart64.S
> rename to s390x/asm/cstart64.S
> index cc86fc7..ace0c0d 100644
> --- a/s390x/cstart64.S
> +++ b/s390x/asm/cstart64.S
> @@ -3,14 +3,17 @@
>   * s390x startup code
>   *
>   * Copyright (c) 2017 Red Hat Inc
> + * Copyright (c) 2019 IBM Corp.

2020 ?

>   *
>   * Authors:
>   *  Thomas Huth <thuth@redhat.com>
>   *  David Hildenbrand <david@redhat.com>
> + *  Janosch Frank <frankja@linux.ibm.com>
>   */
>  #include <asm/asm-offsets.h>
>  #include <asm/sigp.h>

[...]

> diff --git a/s390x/asm/lib.S b/s390x/asm/lib.S
> new file mode 100644
> index 0000000..4d78ec6
> --- /dev/null
> +++ b/s390x/asm/lib.S
> @@ -0,0 +1,65 @@
> +/* SPDX-License-Identifier: GPL-2.0-only */
> +/*
> + * s390x assembly library
> + *
> + * Copyright (c) 2019 IBM Corp.

also 2020?

> + *
> + * Authors:
> + *    Janosch Frank <frankja@linux.ibm.com>
> + */
> +#include <asm/asm-offsets.h>
> +#include <asm/sigp.h>
> +
> +#include "macros.S"
> +
> +/*
> + * load_reset calling convention:
> + * %r2 subcode (0 or 1)
> + */
> +.globl diag308_load_reset
> +diag308_load_reset:
> +	SAVE_REGS
> +	/* Backup current PSW mask, as we have to restore it on
> success */
> +	epsw	%r0, %r1
> +	st	%r0, GEN_LC_SW_INT_PSW
> +	st	%r1, GEN_LC_SW_INT_PSW + 4
> +	/* Load reset psw mask (short psw, 64 bit) */
> +	lg	%r0, reset_psw
> +	/* Load the success label address */
> +	larl    %r1, 0f
> +	/* Or it to the mask */
> +	ogr	%r0, %r1
> +	/* Store it at the reset PSW location (real 0x0) */
> +	stg	%r0, 0
> +	/* Do the reset */
> +	diag    %r0,%r2,0x308
> +	/* Failure path */
> +	xgr	%r2, %r2
> +	br	%r14
> +	/* Success path */
> +	/* load a cr0 that has the AFP control bit which enables all
> FPRs */ +0:	larl	%r1, initial_cr0
> +	lctlg	%c0, %c0, 0(%r1)
> +	RESTORE_REGS
> +	lhi	%r2, 1
> +	larl	%r0, 1f
> +	stg	%r0, GEN_LC_SW_INT_PSW + 8
> +	lpswe	GEN_LC_SW_INT_PSW
> +1:	br	%r14
> +
> +/* Sets up general registers and cr0 when a new cpu is brought
> online. */ +.globl smp_cpu_setup_state
> +smp_cpu_setup_state:
> +	xgr	%r1, %r1
> +	lmg     %r0, %r15, GEN_LC_SW_INT_GRS
> +	lctlg   %c0, %c0, GEN_LC_SW_INT_CRS
> +	/* We should only go once through cpu setup and not for
> every restart */
> +	stg	%r14, GEN_LC_RESTART_NEW_PSW + 8
> +	larl	%r14, 0f
> +	lpswe	GEN_LC_SW_INT_PSW
> +	/* If the function returns, just loop here */
> +0:	j	0
> +
> +	.align	8
> +reset_psw:
> +	.quad	0x0008000180000000
> diff --git a/s390x/asm/macros.S b/s390x/asm/macros.S
> new file mode 100644
> index 0000000..37a6a63
> --- /dev/null
> +++ b/s390x/asm/macros.S
> @@ -0,0 +1,77 @@
> +/* SPDX-License-Identifier: GPL-2.0-only */
> +/*
> + * s390x assembly macros
> + *
> + * Copyright (c) 2017 Red Hat Inc
> + * Copyright (c) 2020 IBM Corp.
> + *
> + * Authors:
> + *  Pierre Morel <pmorel@linux.ibm.com>
> + *  David Hildenbrand <david@redhat.com>
> + */
> +#include <asm/asm-offsets.h>
> +	.macro SAVE_REGS
> +	/* save grs 0-15 */
> +	stmg	%r0, %r15, GEN_LC_SW_INT_GRS
> +	/* save crs 0-15 */
> +	stctg	%c0, %c15, GEN_LC_SW_INT_CRS
> +	/* load a cr0 that has the AFP control bit which enables all
> FPRs */
> +	larl	%r1, initial_cr0
> +	lctlg	%c0, %c0, 0(%r1)
> +	/* save fprs 0-15 + fpc */
> +	la	%r1, GEN_LC_SW_INT_FPRS
> +	.irp i, 0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15
> +	std	\i, \i * 8(%r1)
> +	.endr
> +	stfpc	GEN_LC_SW_INT_FPC
> +	.endm
> +
> +	.macro RESTORE_REGS
> +	/* restore fprs 0-15 + fpc */
> +	la	%r1, GEN_LC_SW_INT_FPRS
> +	.irp i, 0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15
> +	ld	\i, \i * 8(%r1)
> +	.endr
> +	lfpc	GEN_LC_SW_INT_FPC
> +	/* restore crs 0-15 */
> +	lctlg	%c0, %c15, GEN_LC_SW_INT_CRS
> +	/* restore grs 0-15 */
> +	lmg	%r0, %r15, GEN_LC_SW_INT_GRS
> +	.endm
> +
> +/* Save registers on the stack (r15), so we can have stacked
> interrupts. */
> +	.macro SAVE_REGS_STACK
> +	/* Allocate a stack frame for 15 general registers */
> +	slgfi   %r15, 15 * 8
> +	/* Store registers r0 to r14 on the stack */
> +	stmg    %r0, %r14, 0(%r15)
> +	/* Allocate a stack frame for 16 floating point registers */
> +	/* The size of a FP register is the size of an double word */
> +	slgfi   %r15, 16 * 8
> +	/* Save fp register on stack: offset to SP is multiple of
> reg number */
> +	.irp i, 0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15
> +	std	\i, \i * 8(%r15)
> +	.endr
> +	/* Save fpc, but keep stack aligned on 64bits */
> +	slgfi   %r15, 8
> +	efpc	%r0
> +	stg	%r0, 0(%r15)
> +	.endm
> +
> +/* Restore the register in reverse order */
> +	.macro RESTORE_REGS_STACK
> +	/* Restore fpc */
> +	lfpc	0(%r15)
> +	algfi	%r15, 8
> +	/* Restore fp register from stack: SP still where it was
> left */
> +	/* and offset to SP is a multiple of reg number */
> +	.irp i, 0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15
> +	ld	\i, \i * 8(%r15)
> +	.endr
> +	/* Now that we're done, rewind the stack pointer by 16
> double word */
> +	algfi   %r15, 16 * 8
> +	/* Load the registers from stack */
> +	lmg     %r0, %r14, 0(%r15)
> +	/* Rewind the stack by 15 double word */
> +	algfi   %r15, 15 * 8
> +	.endm