| Message ID | 20190110154151.24233-4-frankja@linux.ibm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | s390x: Add cross hypervisor and disk boot | expand |
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
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.*) }