To ensure that only verified code is executed the stage 3 loader has
to check if the load psw points to an address that has previously been
verified by the machine loader.
If secure boot is enabled the IPL process will only continue if the
verification was successful.
Signed-off-by: Stefan Haberland <sth@linux.ibm.com>
Acked-by: Peter Oberparleiter <oberpar@linux.ibm.com>
Signed-off-by: Jan Höppner <hoeppner@linux.ibm.com>
The first component that gets control after IPL is the zIPL-provided
stage 3 boot loader. This boot loader is based on a binary image linked
into the zIPL executable. When preparing a disk for IPL, zIPL updates
runtime parameters in the boot loader image and writes the resulting
data to disk.
To support the Secure Boot firmware feature, the stage 3 code must be
signed, and can therefore no longer contain variable parameter portions.
Also the boot loader image should be accessible as a separate file to
enable the use of external programs for creating the signature.
This patch moves the stage 3 boot loader code to an external file
location and splits out the parameter portion into a separate, unsigned
on-disk component.
The new memory layout of the stage 3 loader during its execution looks
as follows:
* 0x0000-0x1fff Lowcore
* 0x2000-0x5fff Memory allocation (heap)
* 0x7000-0x8fff free
* 0x9000-0x9fff Stage3 parameter
* 0xa000-0xcfff Stage3 code
* 0xd000-0xefff Section: bss, rodata, data
* 0xf000-0xffff Stack
Signed-off-by: Stefan Haberland <sth@linux.ibm.com>
Reviewed-by: Peter Oberparleiter <oberpar@linux.ibm.com>
Signed-off-by: Jan Höppner <hoeppner@linux.ibm.com>
The binary Linux kernel image is built to be loaded to memory address
0x0 but the first 64 kbyte contain an IPL header that is not used for
disk IPL. zIPL strips away this IPL header when writing IPL records to
disk, loads the remaining data to memory address 0x10000 and uses the
memory area below that for its own boot loader code.
The Secure Boot firmware feature checks the integrity of an installed
image during IPL using a checksum that was generated for the full image.
Since the checksum becomes invalid if the IPL header is removed, zIPL
must be changed to write the full image to disk.
This patch modifies the zIPL logic to no longer strip away the IPL
header. Instead the full image is loaded to a higher memory address and
relocated by the stage 3 boot loader code to its final location.
Signed-off-by: Stefan Haberland <sth@linux.ibm.com>
Reviewed-by: Peter Oberparleiter <oberpar@linux.ibm.com>
Signed-off-by: Jan Höppner <hoeppner@linux.ibm.com>
This commit is based on the s390-tools-1.39.0 version.
Changes on top of s390-tools-1.39.0:
- Add MIT license to all source files
- Add LICENSE file
- Transform REAMDE to README.md (markdown)
- Add AUTHORS.md file
- Add CONTRIBUTING.md file
- Move changelog from README to CHANGELOG.md file
Reviewed-by: Stefan Haberland <sth@linux.vnet.ibm.com>
Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
