Re: [kvm-unit-tests PATCH v2 3/8] RFC: s390x: Define STACK_FRAME_INT_SIZE macro

Thomas Huth
2021-02-17T15:40:28Z

On 17/02/2021 15.41, Janosch Frank wrote:
> Using sizeof is safer than using magic constants. However, it doesn't
> really fit into asm-offsets.h as it's not an offset so I'm happy to
> receive suggestions on where to put it.
>
> Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
> ---
> lib/s390x/asm-offsets.c | 1 +
> s390x/macros.S | 4 ++--
> 2 files changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/lib/s390x/asm-offsets.c b/lib/s390x/asm-offsets.c
> index 96cb21cf..2658b59a 100644
> --- a/lib/s390x/asm-offsets.c
> +++ b/lib/s390x/asm-offsets.c
> @@ -86,6 +86,7 @@ int main(void)
> OFFSET(STACK_FRAME_INT_CRS, stack_frame_int, crs);
> OFFSET(STACK_FRAME_INT_GRS0, stack_frame_int, grs0);
> OFFSET(STACK_FRAME_INT_GRS1, stack_frame_int, grs1);
> + DEFINE(STACK_FRAME_INT_SIZE, sizeof(struct stack_frame_int));
>
> return 0;
> }
> diff --git a/s390x/macros.S b/s390x/macros.S
> index d7eeeb55..a7d62c6f 100644
> --- a/s390x/macros.S
> +++ b/s390x/macros.S
> @@ -43,14 +43,14 @@
> /* Save registers on the stack (r15), so we can have stacked interrupts. */
> .macro SAVE_REGS_STACK
> /* Allocate a full stack frame */
> - slgfi %r15, 32 * 8 + 4 * 8
> + slgfi %r15, STACK_FRAME_INT_SIZE
> /* Store registers r0 to r14 on the stack */
> stmg %r2, %r15, STACK_FRAME_INT_GRS0(%r15)
> stg %r0, STACK_FRAME_INT_GRS1(%r15)
> stg %r1, STACK_FRAME_INT_GRS1 + 8(%r15)
> /* Store the gr15 value before we allocated the new stack */
> lgr %r0, %r15
> - algfi %r0, 32 * 8 + 4 * 8
> + algfi %r0, STACK_FRAME_INT_SIZE

Ah, well, that of course fixes the problem that I had with the previous
patch. I'd suggest to merge it into patch 2.

Thomas