Patchwork [kvm-unit-tests,v5,03/11] s390x: Make tests bootable from disk

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Submitter Janosch Frank
Date Jan. 10, 2019, 3:41 p.m.
Message ID <20190110154151.24233-4-frankja@linux.ibm.com>
Download mbox | patch
Permalink /patch/696929/
State New
Headers show

Comments

Janosch Frank - Jan. 10, 2019, 3:41 p.m.
Currently tests are run with the --kernel option of Qemu, which will
load the ELF file and jump to the start address. When booting from
disk, we need to specify a start address. This is done by setting the
initial short PSW at 0x0.

.text was moved to 0x11000 because the bootloader can write from
0x10480 until 0x11000 if it has a lot to write. 0x10480 to 0x10600 was
not enough safe space.

Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
---
 s390x/cstart64.S |  8 +++++++-
 s390x/flat.lds   | 13 ++++++++++++-
 2 files changed, 19 insertions(+), 2 deletions(-)
Thomas Huth - Jan. 11, 2019, 9:02 a.m.
On 2019-01-10 16:41, Janosch Frank wrote:
> Currently tests are run with the --kernel option of Qemu, which will
> load the ELF file and jump to the start address. When booting from
> disk, we need to specify a start address. This is done by setting the
> initial short PSW at 0x0.
> 
> .text was moved to 0x11000 because the bootloader can write from
> 0x10480 until 0x11000 if it has a lot to write. 0x10480 to 0x10600 was
> not enough safe space.
> 
> Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
> Reviewed-by: Thomas Huth <thuth@redhat.com>
> Reviewed-by: David Hildenbrand <david@redhat.com>
> ---
>  s390x/cstart64.S |  8 +++++++-
>  s390x/flat.lds   | 13 ++++++++++++-
>  2 files changed, 19 insertions(+), 2 deletions(-)
> 
> diff --git a/s390x/cstart64.S b/s390x/cstart64.S
> index dc7ddd6..385915e 100644
> --- a/s390x/cstart64.S
> +++ b/s390x/cstart64.S
> @@ -14,7 +14,13 @@
>  
>  .section .init
>  
> -/* entry point - for KVM + TCG we directly start in 64 bit mode */
> +/*
> + * Short init between 0x10000 and 0x10480 and then jump to 0x11000.
> + * 0x10480 - 0x11000 are written to by bootloader.
> + *
> + * For KVM and TCG kernel boot we are in 64 bit z/Arch mode.
> + * When booting from disk the initial short psw is in 31 bit mode.
> + */
>  	.globl start
>  start:
>  	/* setup stack */
> diff --git a/s390x/flat.lds b/s390x/flat.lds
> index b6e2172..977af7c 100644
> --- a/s390x/flat.lds
> +++ b/s390x/flat.lds
> @@ -1,10 +1,21 @@
>  SECTIONS
>  {
> +	/*
> +	 * Initial short psw for disk boot, with 31 bit addressing for
> +	 * non z/Arch environment compatibility and the instruction
> +	 * address 0x10000 (cstart64.S .init).
> +	 */
> +	.lowcore : {
> +		. = 0;
> +		 LONG(0x00080000)
> +		 LONG(0x80010000)
> +	}
> +	. = 0x10000;

In case you respin: I think we could/should remove the "-Ttext=0x10000"
from the s390x/Makefile now.

 Thomas

Patch

diff --git a/s390x/cstart64.S b/s390x/cstart64.S
index dc7ddd6..385915e 100644
--- a/s390x/cstart64.S
+++ b/s390x/cstart64.S
@@ -14,7 +14,13 @@ 
 
 .section .init
 
-/* entry point - for KVM + TCG we directly start in 64 bit mode */
+/*
+ * Short init between 0x10000 and 0x10480 and then jump to 0x11000.
+ * 0x10480 - 0x11000 are written to by bootloader.
+ *
+ * For KVM and TCG kernel boot we are in 64 bit z/Arch mode.
+ * When booting from disk the initial short psw is in 31 bit mode.
+ */
 	.globl start
 start:
 	/* setup stack */
diff --git a/s390x/flat.lds b/s390x/flat.lds
index b6e2172..977af7c 100644
--- a/s390x/flat.lds
+++ b/s390x/flat.lds
@@ -1,10 +1,21 @@ 
 SECTIONS
 {
+	/*
+	 * Initial short psw for disk boot, with 31 bit addressing for
+	 * non z/Arch environment compatibility and the instruction
+	 * address 0x10000 (cstart64.S .init).
+	 */
+	.lowcore : {
+		. = 0;
+		 LONG(0x00080000)
+		 LONG(0x80010000)
+	}
+	. = 0x10000;
 	.text : {
 		*(.init)
 		. = 0x480;
 		ipl_args = .;
-		. = 0x600;
+		.  = 0x1000;
 		*(.text)
 		*(.text.*)
 	}