kernel.git/arch/s390/kernel/vmlinux.lds.S, branch linux-4.19.y

s390: discard .interp section

2023-03-11T15:31:48Z

commit e9c9cb90e76ffaabcc7ca8f275d9e82195fd6367 upstream. When debugging vmlinux with QEMU + GDB, the following GDB error may occur: (gdb) c Continuing. Warning: Cannot insert breakpoint -1. Cannot access memory at address 0xffffffffffff95c0 Command aborted. (gdb) The reason is that, when .interp section is present, GDB tries to locate the file specified in it in memory and put a number of breakpoints there (see enable_break() function in gdb/solib-svr4.c). Sometimes GDB finds a bogus location that matches its heuristics, fails to set a breakpoint and stops. This makes further debugging impossible. The .interp section contains misleading information anyway (vmlinux does not need ld.so), so fix by discarding it. Signed-off-by: Ilya Leoshkevich Cc: Signed-off-by: Heiko Carstens Signed-off-by: Greg Kroah-Hartman

s390: fix nospec table alignments

2022-09-15T10:17:04Z

commit c9305b6c1f52060377c72aebe3a701389e9f3172 upstream. Add proper alignment for .nospec_call_table and .nospec_return_table in vmlinux. [hca@linux.ibm.com]: The problem with the missing alignment of the nospec tables exist since a long time, however only since commit e6ed91fd0768 ("s390/alternatives: remove padding generation code") and with CONFIG_RELOCATABLE=n the kernel may also crash at boot time. The above named commit reduced the size of struct alt_instr by one byte, so its new size is 11 bytes. Therefore depending on the number of cpu alternatives the size of the __alt_instructions array maybe odd, which again also causes that the addresses of the nospec tables will be odd. If the address of __nospec_call_start is odd and the kernel is compiled With CONFIG_RELOCATABLE=n the compiler may generate code that loads the address of __nospec_call_start with a 'larl' instruction. This will generate incorrect code since the 'larl' instruction only works with even addresses. In result the members of the nospec tables will be accessed with an off-by-one offset, which subsequently may lead to addressing exceptions within __nospec_revert(). Fixes: f19fbd5ed642 ("s390: introduce execute-trampolines for branches") Signed-off-by: Josh Poimboeuf Link: https://lore.kernel.org/r/8719bf1ce4a72ebdeb575200290094e9ce047bcc.1661557333.git.jpoimboe@kernel.org Cc: # 4.16 Reviewed-by: Heiko Carstens Signed-off-by: Heiko Carstens Signed-off-by: Vasily Gorbik Signed-off-by: Greg Kroah-Hartman

s390: put _stext and _etext into .text section

2019-08-29T06:28:41Z

[ Upstream commit 24350fdadbdec780406a1ef988e6cd3875e374a8 ] Perf relies on _etext and _stext symbols being one of 't', 'T', 'v' or 'V'. Put them into .text section to guarantee that. Also moves padding to page boundary inside .text which has an effect that .text section is now padded with nops rather than 0's, which apparently has been the initial intention for specifying 0x0700 fill expression. Reported-by: Thomas Richter Tested-by: Thomas Richter Suggested-by: Andreas Krebbel Signed-off-by: Vasily Gorbik Signed-off-by: Sasha Levin

s390: move _text to an actual .text start

2018-07-02T09:25:00Z

Since the uncompressed image .text section starts at 0x100000 now there is no need to redefine _text to something else to make perf happy. Reviewed-by: Heiko Carstens Signed-off-by: Vasily Gorbik Signed-off-by: Martin Schwidefsky

s390: correct _stext offset

2018-07-02T09:24:59Z

Avoid unnecessary rewrite of psw and merge _stext into startup_continue. This allows to move _stext definition to vmlinux.lds.S, where _etext is also defined and set _stext to the actual beginning of .text at 0x100000. This fixes the problem with setting the last .text page as not-executable due to vmem_map_init relying on page alinged _stext and _etext. Fixes: bd79d6632958 ("s390/decompressor: trim the kernel image up to 1M") Reported-by: Nils Hoppmann Reviewed-by: Heiko Carstens Signed-off-by: Vasily Gorbik Signed-off-by: Martin Schwidefsky

s390: get rid of the first mb of uncompressed image

2018-07-02T09:24:58Z

Instead of generating uncompressed kernel image starting at 0, filling first mb with zeros (with ".org 0x100000") and then trimming it off from vmlinux.bin before compression, simply generate a kernel image starting from 0x100000. Reviewed-by: Heiko Carstens Signed-off-by: Vasily Gorbik Signed-off-by: Martin Schwidefsky

s390: put expoline execute-trampolines into .text section

2018-07-02T09:24:57Z

Currently none of the vmlinux linker script patterns in .text section match expoline execute-trampolines, and they end up as separate sections: .text.__s390_indirect_jump_r1, .text.__s390x_indirect_jump_r1use_r9, .text.__s390x_indirect_branch_4_1use_6, ... Add a pattern to match them all. Reviewed-by: Heiko Carstens Signed-off-by: Vasily Gorbik Signed-off-by: Martin Schwidefsky

s390/boot: make head.S and als.c be part of the decompressor only

2018-06-25T08:14:38Z

Since uncompressed kernel image does not have to be bootable anymore, move head.S, head_kdump.S and als.c to boot/ folder and compile them in just in the decompressor. Reviewed-by: Heiko Carstens Signed-off-by: Vasily Gorbik Signed-off-by: Martin Schwidefsky

s390: remove no-op macro VMLINUX_SYMBOL()

2018-05-23T06:06:55Z

VMLINUX_SYMBOL() is no-op unless CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX is defined. It has ever been selected only by BLACKFIN and METAG. VMLINUX_SYMBOL() is unneeded for s390-specific code. Signed-off-by: Masahiro Yamada Signed-off-by: Heiko Carstens Signed-off-by: Martin Schwidefsky

s390: introduce execute-trampolines for branches

2018-02-07T14:57:02Z

Add CONFIG_EXPOLINE to enable the use of the new -mindirect-branch= and -mfunction_return= compiler options to create a kernel fortified against the specte v2 attack. With CONFIG_EXPOLINE=y all indirect branches will be issued with an execute type instruction. For z10 or newer the EXRL instruction will be used, for older machines the EX instruction. The typical indirect call basr %r14,%r1 is replaced with a PC relative call to a new thunk brasl %r14,__s390x_indirect_jump_r1 The thunk contains the EXRL/EX instruction to the indirect branch __s390x_indirect_jump_r1: exrl 0,0f j . 0: br %r1 The detour via the execute type instruction has a performance impact. To get rid of the detour the new kernel parameter "nospectre_v2" and "spectre_v2=[on,off,auto]" can be used. If the parameter is specified the kernel and module code will be patched at runtime. Signed-off-by: Martin Schwidefsky