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 <gerald.schaefer@de.ibm.com>
Reviewed-by: Philipp Rudo <prudo@linux.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
This commit is contained in:
Gerald Schaefer
2019-02-03 21:35:45 +01:00
committed by Martin Schwidefsky
parent 833b441ec0
commit 805bc0bc23
11 changed files with 124 additions and 42 deletions

View File

@@ -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;
}