lwn.git/arch/s390/boot, branch docs-5.3

s390/boot: fix compiler error due to missing awk strtonum

2019-05-07T12:37:14+00:00

The strtonum awk function is a GNU extension and is not available with all versions of awk. The link of bzImage fails with this error message: >> awk: line 2: function or never defined >> awk: line 2: function strtonum never defined objcopy: --pad-to: bad number: arch/s390/boot/compressed/vmlinux Drop the awk script and the --pad-to objcopy parameter it generated and use a FILL pattern with an appropriate alignment in the linker script for the arch/s390/boot/compressed/vmlinux file. Fixes: f6780686525c ("s390/boot: pad bzImage to 4K") Reported-by: kbuild test robot Suggested-by: Vasily Gorbik Signed-off-by: Martin Schwidefsky

s390: fix clang -Wpointer-sign warnigns in boot code

2019-05-03T15:17:58+00:00

The arch/s390/boot directory is built with its own set of compiler options that does not include -Wno-pointer-sign like the rest of the kernel does, this causes a lot of harmless but correct warnings when building with clang. For the atomics, we can add type casts to avoid the warnings, for everything else the easiest way is to slightly adapt the types to be more consistent. Signed-off-by: Arnd Bergmann Reviewed-by: Nick Desaulniers Signed-off-by: Heiko Carstens Signed-off-by: Martin Schwidefsky

s390: only build for new CPUs with clang

2019-05-03T15:17:58+00:00

llvm does does not understand -march=z9-109 and older target specifiers, so disable the respective Kconfig settings and the logic to make the boot code work on old systems when building with clang. Part of the early boot code is normally compiled with -march=z900 for maximum compatibility. This also has to get changed with clang to the oldest supported ISA, which is -march=z10 here. Signed-off-by: Arnd Bergmann Signed-off-by: Heiko Carstens Signed-off-by: Martin Schwidefsky

s390: simplify disabled_wait

2019-05-02T11:54:11+00:00

The disabled_wait() function uses its argument as the PSW address when it stops the CPU with a wait PSW that is disabled for interrupts. The different callers sometimes use a specific number like 0xdeadbeef to indicate a specific failure, the early boot code uses 0 and some other calls sites use __builtin_return_address(0). At the time a dump is created the current PSW and the registers of a CPU are written to lowcore to make them avaiable to the dump analysis tool. For a CPU stopped with disabled_wait the PSW and the registers do not really make sense together, the PSW address does not point to the function the registers belong to. Simplify disabled_wait() by using _THIS_IP_ for the PSW address and drop the argument to the function. Signed-off-by: Martin Schwidefsky

s390: use proper expoline sections for .dma code

2019-05-02T11:54:11+00:00

The text_dma.S code uses its own macro to generate an inline version of an expoline. To make it easier to identify all expolines in the kernel use a thunk and a branch to the thunk just like the rest of the kernel code does it. The name of the text_dma.S expoline thunk is __dma__s390_indirect_jump_r14 and the section is named .dma.text.__s390_indirect_jump_r14. This will be needed for the objtool support. Signed-off-by: Martin Schwidefsky

s390: add missing ENDPROC statements to assembler functions

2019-05-02T11:54:11+00:00

The assembler code in arch/s390 misses proper ENDPROC statements to properly end functions in a few places. Add them. Signed-off-by: Martin Schwidefsky

s390/kernel: add support for kernel address space layout randomization (KASLR)

2019-04-29T08:47:10+00:00

This patch adds support for relocating the kernel to a random address. The random kernel offset is obtained from cpacf, using either TRNG, PRNO, or KMC_PRNG, depending on supported MSA level. KERNELOFFSET is added to vmcoreinfo, for crash --kaslr support. Signed-off-by: Gerald Schaefer Reviewed-by: Philipp Rudo Signed-off-by: Martin Schwidefsky

s390/kernel: introduce .dma sections

2019-04-29T08:47:10+00:00

With a relocatable kernel that could reside at any place in memory, code and data that has to stay below 2 GB needs special handling. This patch introduces .dma sections for such text, data and ex_table. The sections will be part of the decompressor kernel, so they will not be relocated and stay below 2 GB. Their location is passed over to the decompressed / relocated kernel via the .boot.preserved.data section. The duald and aste for control register setup also need to stay below 2 GB, so move the setup code from arch/s390/kernel/head64.S to arch/s390/boot/head.S. The duct and linkage_stack could reside above 2 GB, but their content has to be preserved for the decompresed kernel, so they are also moved into the .dma section. The start and end address of the .dma sections is added to vmcoreinfo, for crash support, to help debugging in case the kernel crashed there. Signed-off-by: Gerald Schaefer Reviewed-by: Philipp Rudo Signed-off-by: Martin Schwidefsky

s390/sclp: do not use static sccbs

2019-04-29T08:47:10+00:00

The sccbs for init/read/sdias/early have to be located below 2 GB, and they are currently defined as a static buffer. With a relocatable kernel that could reside at any place in memory, this will no longer guarantee the location below 2 GB, so use a dynamic GFP_DMA allocation instead. The sclp_early_sccb buffer needs special handling, as it can be used very early, and by both the decompressor and also the decompressed kernel. Therefore, a fixed 4 KB buffer is introduced at 0x11000, the former PARMAREA_END. The new PARMAREA_END is now 0x12000, and it is renamed to HEAD_END, as it is rather the end of head.S and not the end of the parmarea. Signed-off-by: Gerald Schaefer Reviewed-by: Philipp Rudo Signed-off-by: Martin Schwidefsky

s390/kernel: build a relocatable kernel

2019-04-29T08:47:10+00:00

This patch adds support for building a relocatable kernel with -fPIE. The kernel will be relocated to 0 early in the boot process. Signed-off-by: Gerald Schaefer Reviewed-by: Philipp Rudo Signed-off-by: Martin Schwidefsky