From 805bc0bc238f7209fca5e39c152b0d3c12046ac9 Mon Sep 17 00:00:00 2001 From: Gerald Schaefer Date: Sun, 3 Feb 2019 21:35:45 +0100 Subject: s390/kernel: build a relocatable kernel 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 --- arch/s390/kernel/Makefile | 2 +- arch/s390/kernel/machine_kexec_file.c | 44 ++-------------------------- arch/s390/kernel/machine_kexec_reloc.c | 53 ++++++++++++++++++++++++++++++++++ arch/s390/kernel/vmlinux.lds.S | 15 ++++++++++ 4 files changed, 72 insertions(+), 42 deletions(-) create mode 100644 arch/s390/kernel/machine_kexec_reloc.c (limited to 'arch/s390/kernel') diff --git a/arch/s390/kernel/Makefile b/arch/s390/kernel/Makefile index d28acd7ba81e..19425605a83d 100644 --- a/arch/s390/kernel/Makefile +++ b/arch/s390/kernel/Makefile @@ -51,7 +51,7 @@ obj-y += debug.o irq.o ipl.o dis.o diag.o vdso.o early_nobss.o obj-y += sysinfo.o lgr.o os_info.o machine_kexec.o pgm_check.o obj-y += runtime_instr.o cache.o fpu.o dumpstack.o guarded_storage.o sthyi.o obj-y += entry.o reipl.o relocate_kernel.o kdebugfs.o alternative.o -obj-y += nospec-branch.o ipl_vmparm.o +obj-y += nospec-branch.o ipl_vmparm.o machine_kexec_reloc.o extra-y += head64.o vmlinux.lds diff --git a/arch/s390/kernel/machine_kexec_file.c b/arch/s390/kernel/machine_kexec_file.c index 48cab9600ed9..42c23a5c8229 100644 --- a/arch/s390/kernel/machine_kexec_file.c +++ b/arch/s390/kernel/machine_kexec_file.c @@ -290,7 +290,7 @@ int arch_kexec_apply_relocations_add(struct purgatory_info *pi, const Elf_Shdr *symtab) { Elf_Rela *relas; - int i; + int i, r_type; relas = (void *)pi->ehdr + relsec->sh_offset; @@ -324,46 +324,8 @@ int arch_kexec_apply_relocations_add(struct purgatory_info *pi, addr = section->sh_addr + relas[i].r_offset; - switch (ELF64_R_TYPE(relas[i].r_info)) { - case R_390_8: /* Direct 8 bit. */ - *(u8 *)loc = val; - break; - case R_390_12: /* Direct 12 bit. */ - *(u16 *)loc &= 0xf000; - *(u16 *)loc |= val & 0xfff; - break; - case R_390_16: /* Direct 16 bit. */ - *(u16 *)loc = val; - break; - case R_390_20: /* Direct 20 bit. */ - *(u32 *)loc &= 0xf00000ff; - *(u32 *)loc |= (val & 0xfff) << 16; /* DL */ - *(u32 *)loc |= (val & 0xff000) >> 4; /* DH */ - break; - case R_390_32: /* Direct 32 bit. */ - *(u32 *)loc = val; - break; - case R_390_64: /* Direct 64 bit. */ - *(u64 *)loc = val; - break; - case R_390_PC16: /* PC relative 16 bit. */ - *(u16 *)loc = (val - addr); - break; - case R_390_PC16DBL: /* PC relative 16 bit shifted by 1. */ - *(u16 *)loc = (val - addr) >> 1; - break; - case R_390_PC32DBL: /* PC relative 32 bit shifted by 1. */ - *(u32 *)loc = (val - addr) >> 1; - break; - case R_390_PC32: /* PC relative 32 bit. */ - *(u32 *)loc = (val - addr); - break; - case R_390_PC64: /* PC relative 64 bit. */ - *(u64 *)loc = (val - addr); - break; - default: - break; - } + r_type = ELF64_R_TYPE(relas[i].r_info); + arch_kexec_do_relocs(r_type, loc, val, addr); } return 0; } diff --git a/arch/s390/kernel/machine_kexec_reloc.c b/arch/s390/kernel/machine_kexec_reloc.c new file mode 100644 index 000000000000..1dded39239f8 --- /dev/null +++ b/arch/s390/kernel/machine_kexec_reloc.c @@ -0,0 +1,53 @@ +// SPDX-License-Identifier: GPL-2.0 +#include + +int arch_kexec_do_relocs(int r_type, void *loc, unsigned long val, + unsigned long addr) +{ + switch (r_type) { + case R_390_NONE: + break; + case R_390_8: /* Direct 8 bit. */ + *(u8 *)loc = val; + break; + case R_390_12: /* Direct 12 bit. */ + *(u16 *)loc &= 0xf000; + *(u16 *)loc |= val & 0xfff; + break; + case R_390_16: /* Direct 16 bit. */ + *(u16 *)loc = val; + break; + case R_390_20: /* Direct 20 bit. */ + *(u32 *)loc &= 0xf00000ff; + *(u32 *)loc |= (val & 0xfff) << 16; /* DL */ + *(u32 *)loc |= (val & 0xff000) >> 4; /* DH */ + break; + case R_390_32: /* Direct 32 bit. */ + *(u32 *)loc = val; + break; + case R_390_64: /* Direct 64 bit. */ + *(u64 *)loc = val; + break; + case R_390_PC16: /* PC relative 16 bit. */ + *(u16 *)loc = (val - addr); + break; + case R_390_PC16DBL: /* PC relative 16 bit shifted by 1. */ + *(u16 *)loc = (val - addr) >> 1; + break; + case R_390_PC32DBL: /* PC relative 32 bit shifted by 1. */ + *(u32 *)loc = (val - addr) >> 1; + break; + case R_390_PC32: /* PC relative 32 bit. */ + *(u32 *)loc = (val - addr); + break; + case R_390_PC64: /* PC relative 64 bit. */ + *(u64 *)loc = (val - addr); + break; + case R_390_RELATIVE: + *(unsigned long *) loc = val; + break; + default: + return 1; + } + return 0; +} diff --git a/arch/s390/kernel/vmlinux.lds.S b/arch/s390/kernel/vmlinux.lds.S index 6ef9c62bb01b..49d55327de0b 100644 --- a/arch/s390/kernel/vmlinux.lds.S +++ b/arch/s390/kernel/vmlinux.lds.S @@ -144,6 +144,18 @@ SECTIONS INIT_DATA_SECTION(0x100) PERCPU_SECTION(0x100) + + .dynsym ALIGN(8) : { + __dynsym_start = .; + *(.dynsym) + __dynsym_end = .; + } + .rela.dyn ALIGN(8) : { + __rela_dyn_start = .; + *(.rela*) + __rela_dyn_end = .; + } + . = ALIGN(PAGE_SIZE); __init_end = .; /* freed after init ends here */ @@ -165,6 +177,9 @@ SECTIONS QUAD(__boot_data_preserved_start) /* bootdata_preserved_off */ QUAD(__boot_data_preserved_end - __boot_data_preserved_start) /* bootdata_preserved_size */ + QUAD(__dynsym_start) /* dynsym_start */ + QUAD(__rela_dyn_start) /* rela_dyn_start */ + QUAD(__rela_dyn_end) /* rela_dyn_end */ } :NONE /* Debugging sections. */ -- cgit v1.2.3-59-g8ed1b