kernel/linux.git/arch/s390/include/asm/setup.h, branch v6.12.80

s390/setup: Recognize sequential instruction fetching facility

2024-08-29T20:56:34+00:00

When sequential instruction fetching facility is present, certain guarantees are provided for code patching. In particular, atomic overwrites within 8 aligned bytes is safe from an instruction-fetching point of view. Reviewed-by: Heiko Carstens Signed-off-by: Vasily Gorbik

s390/early: Dump register contents and call trace for early crashes

2024-08-22T17:28:11+00:00

If the early program check handler cannot resolve a program check dump register contents and a call trace to the console before loading a disabled wait psw. This makes debugging much easier. Emit an extra message with early_printk() for cases where regular printk() via the early console is not yet working so that at least some information is available. Signed-off-by: Heiko Carstens Acked-by: Vasily Gorbik Signed-off-by: Vasily Gorbik

s390: Replace S390_lowcore by get_lowcore()

2024-06-18T15:01:33+00:00

Replace all S390_lowcore usages in arch/s390/ by get_lowcore(). Acked-by: Heiko Carstens Signed-off-by: Sven Schnelle Signed-off-by: Vasily Gorbik

s390/mm: Move KASLR related to

2024-04-17T11:38:00+00:00

Move everyting KASLR related to , similarly to many other architectures. Acked-by: Heiko Carstens Suggested-by: Heiko Carstens Signed-off-by: Alexander Gordeev

s390/fpu: get rid of MACHINE_HAS_VX

2023-12-11T13:33:07+00:00

Get rid of MACHINE_HAS_VX and replace it with cpu_has_vx() which is a short readable wrapper for "test_facility(129)". Facility bit 129 is set if the vector facility is present. test_facility() returns also true for all bits which are set in the architecture level set of the cpu that the kernel is compiled for. This means that test_facility(129) is a compile time constant which returns true for z13 and later, since the vector facility bit is part of the z13 kernel ALS. In result the compiled code will have less runtime checks, and less code. Reviewed-by: Hendrik Brueckner Signed-off-by: Heiko Carstens Signed-off-by: Alexander Gordeev

s390/cmma: rework no-dat handling

2023-11-05T21:34:58+00:00

Rework the way physical pages are set no-dat / dat: The old way is: - Rely on that all pages are initially marked "dat" - Allocate page tables for the kernel mapping - Enable dat - Walk the whole kernel mapping and set PG_arch_1 bit in all struct pages that belong to pages of kernel page tables - Walk all struct pages and test and clear the PG_arch_1 bit. If the bit is not set, set the page state to no-dat - For all subsequent page table allocations, set the page state to dat (remove the no-dat state) on allocation time Change this rather complex logic to a simpler approach: - Set the whole physical memory (all pages) to "no-dat" - Explicitly set those page table pages to "dat" which are part of the kernel image (e.g. swapper_pg_dir) - For all subsequent page table allocations, set the page state to dat (remove the no-dat state) on allocation time In result the code is simpler, and this also allows to get rid of one odd usage of the PG_arch_1 bit. Reviewed-by: Claudio Imbrenda Signed-off-by: Heiko Carstens Signed-off-by: Vasily Gorbik

s390/cmma: move parsing of cmma kernel parameter to early boot code

2023-11-05T21:34:57+00:00

The "cmma=" kernel command line parameter needs to be parsed early for upcoming changes. Therefore move the parsing code. Note that EX_TABLE handling of cmma_test_essa() needs to be open-coded, since the early boot code doesn't have infrastructure for handling expected exceptions. Reviewed-by: Claudio Imbrenda Signed-off-by: Heiko Carstens Signed-off-by: Vasily Gorbik

s390: remove "noexec" option

2023-08-30T09:03:27+00:00

Do the same like x86 with commit 76ea0025a214 ("x86/cpu: Remove "noexec"") and remove the "noexec" kernel command line option. Reviewed-by: Alexander Gordeev Signed-off-by: Heiko Carstens

s390/mm: move pfault code to own C file

2023-07-29T12:57:18+00:00

The pfault code has nothing to do with regular fault handling. Therefore move it to an own C file. Also add an own pfault header file. This way changes to setup.h don't cause a recompile of the pfault code and vice versa. Reviewed-by: Sven Schnelle Signed-off-by: Heiko Carstens

s390/mm: rework arch_get_mappable_range() callback

2023-07-24T10:12:23+00:00

As per description in mm/memory_hotplug.c platforms should define arch_get_mappable_range() that provides maximum possible addressable physical memory range for which the linear mapping could be created. The current implementation uses VMEM_MAX_PHYS macro as the maximum mappable physical address and it is simply a cast to vmemmap. Since the address is in physical address space the natural upper limit of MAX_PHYSMEM_BITS is honoured: vmemmap_start = min(vmemmap_start, 1UL << MAX_PHYSMEM_BITS); Further, to make sure the identity mapping would not overlay with vmemmap, the size of identity mapping could be stripped like this: ident_map_size = min(ident_map_size, vmemmap_start); Similarily, any other memory that could be added (e.g DCSS segment) should not overlay with vmemmap as well and that is prevented by using vmemmap (VMEM_MAX_PHYS macro) as the upper limit. However, while the use of VMEM_MAX_PHYS brings the desired result it actually poses two issues: 1. As described, vmemmap is handled as a physical address, although it is actually a pointer to struct page in virtual address space. 2. As vmemmap is a virtual address it could have been located anywhere in the virtual address space. However, the desired necessity to honour MAX_PHYSMEM_BITS limit prevents that. Rework arch_get_mappable_range() callback in a way it does not use VMEM_MAX_PHYS macro and does not confuse the notion of virtual vs physical address spacees as result. That paves the way for moving vmemmap elsewhere and optimizing the virtual address space layout. Introduce max_mappable preserved boot variable and let function setup_kernel_memory_layout() set it up. As result, the rest of the code is does not need to know the virtual memory layout specifics. Reviewed-by: Heiko Carstens Signed-off-by: Alexander Gordeev Signed-off-by: Heiko Carstens