linux-dev/arch/s390/boot/startup.c, branch linus/master

s390/boot: get rid of startup archive

2022-05-06T18:45:14Z

The final kernel image is created by linking decompressor object files with a startup archive. The startup archive file however does not contain only optional code and data which can be discarded if not referenced. It also contains mandatory object data like head.o which must never be discarded, even if not referenced. Move the decompresser code and linker script to the boot directory and get rid of the startup archive so everything is kept during link time. Acked-by: Vasily Gorbik Signed-off-by: Heiko Carstens

s390/boot: simplify and fix kernel memory layout setup

2021-11-16T11:29:19Z

Initial KASAN shadow memory range was picked to preserve original kernel modules area position. With protected execution support, which might impose addressing limitation on vmalloc area and hence affect modules area position, current fixed KASAN shadow memory range is only making kernel memory layout setup more complex. So move it to the very end of available virtual space and simplify calculations. At the same time return to previous kernel address space split. In particular commit 0c4f2623b957 ("s390: setup kernel memory layout early") introduced precise identity map size calculation and keeping vmemmap left most starting from a fresh region table entry. This didn't take into account additional mapping region requirement for potential DCSS mapping above available physical memory. So go back to virtual space split between 1:1 mapping & vmemmap array once vmalloc area size is subtracted. Cc: stable@vger.kernel.org Fixes: 0c4f2623b957 ("s390: setup kernel memory layout early") Reported-by: Gerald Schaefer Reviewed-by: Heiko Carstens Reviewed-by: Alexander Gordeev Signed-off-by: Vasily Gorbik Signed-off-by: Heiko Carstens

s390/boot: allocate amode31 section in decompressor

2021-10-04T07:49:37Z

The memory for amode31 section is allocated from the decompressed kernel. Instead, allocate that memory from the decompressor. This is a prerequisite to allow initialization of the virtual memory before the decompressed kernel takes over. Reviewed-by: Heiko Carstens Signed-off-by: Alexander Gordeev Signed-off-by: Vasily Gorbik

s390/boot: factor out offset_vmlinux_info() function

2021-08-25T09:03:33Z

Move offsetting all of vmlinux_info fields to a separate function for better readability. Signed-off-by: Alexander Gordeev Signed-off-by: Vasily Gorbik Signed-off-by: Heiko Carstens

s390/boot: get rid of arithmetics on function pointers

2021-07-27T07:39:22Z

sparse warning: CHECK arch/s390/boot/startup.c arch/s390/boot/startup.c:283:39: error: arithmetics on pointers to functions Signed-off-by: Heiko Carstens

s390/boot: move dma sections from decompressor to decompressed kernel

2021-07-27T07:39:17Z

This change simplifies the task of making the decompressor relocatable. The decompressor's image contains special DMA sections between _sdma and _edma. This DMA segment is loaded at boot as part of the decompressor and then simply handed over to the decompressed kernel. The decompressor itself never uses it in any way. The primary reason for this is the need to keep the aforementioned DMA segment below 2GB which is required by architecture, and because the decompressor is always loaded at a fixed low physical address, it is guaranteed that the DMA region will not cross the 2GB memory limit. If the DMA region had been placed in the decompressed kernel, then KASLR would make this guarantee impossible to fulfill or it would be restricted to the first 2GB of memory address space. This commit moves all DMA sections between _sdma and _edma from the decompressor's image to the decompressed kernel's image. The complete DMA region is placed in the init section of the decompressed kernel and immediately relocated below 2GB at start-up before it is needed by other parts of the decompressed kernel. The relocation of the DMA region happens even if the decompressed kernel is already located below 2GB in order to keep the first implementation simple. The relocation should not have any noticeable impact on boot time because the DMA segment is only a couple of pages. After relocating the DMA sections, the kernel has to fix all references which point into it. In order to automate this, place all variables pointing into the DMA sections in a special .dma.refs section. All such variables must be defined using the new __dma_ref macro. Only variables containing addresses within the DMA sections must be placed in the new .dma.refs section. Furthermore, move the initialization of control registers from the decompressor to the decompressed kernel because some control registers reference tables that must be placed in the DMA data section to guarantee that their addresses are below 2G. Because the decompressed kernel relocates the DMA sections at startup, the content of control registers CR2, CR5 and CR15 must be updated with new addresses after the relocation. The decompressed kernel initializes all control registers early at boot and then updates the content of CR2, CR5 and CR15 as soon as the DMA relocation has occurred. This practically reverts the commit a80313ff91ab ("s390/kernel: introduce .dma sections"). Signed-off-by: Alexander Egorenkov Acked-by: Heiko Carstens Signed-off-by: Heiko Carstens

s390/dump: introduce boot data 'oldmem_data'

2021-07-27T07:39:16Z

The new boot data struct shall replace global variables OLDMEM_BASE and OLDMEM_SIZE. It is initialized in the decompressor and passed to the decompressed kernel. In comparison to the old solution, this one doesn't access data at fixed physical addresses which will become important when the decompressor becomes relocatable. Signed-off-by: Alexander Egorenkov Acked-by: Heiko Carstens Signed-off-by: Heiko Carstens

s390/boot: introduce boot data 'initrd_data'

2021-07-27T07:39:15Z

The new boot data struct shall replace global variables INITRD_START and INITRD_SIZE. It is initialized in the decompressor and passed to the decompressed kernel. In comparison to the old solution, this one doesn't access data at fixed physical addresses which will become important when the decompressor becomes relocatable. Signed-off-by: Alexander Egorenkov Acked-by: Heiko Carstens Signed-off-by: Heiko Carstens

s390/boot: disable Secure Execution in dump mode

2021-07-27T07:39:14Z

A dump kernel is neither required nor able to support Secure Execution. Signed-off-by: Alexander Egorenkov Reviewed-by: Vasily Gorbik Signed-off-by: Heiko Carstens

s390/boot: move uv function declarations to boot/uv.h

2021-07-27T07:39:14Z

The functions adjust_to_uv_max() and uv_query_info() are used only in the decompressor. Therefore, move the function declarations from the global arch/s390/include/asm/uv.h to arch/s390/boot/uv.h. Signed-off-by: Alexander Egorenkov Reviewed-by: Vasily Gorbik Signed-off-by: Heiko Carstens