diff options
Diffstat (limited to 'sysdeps/s390/s390-32/elf/start.S')
| -rw-r--r-- | sysdeps/s390/s390-32/elf/start.S | 82 |
1 files changed, 82 insertions, 0 deletions
diff --git a/sysdeps/s390/s390-32/elf/start.S b/sysdeps/s390/s390-32/elf/start.S index f7290106ce..066f7f0aa1 100644 --- a/sysdeps/s390/s390-32/elf/start.S +++ b/sysdeps/s390/s390-32/elf/start.S @@ -59,6 +59,88 @@ .globl _start .type _start,@function _start: + /* Check if the kernel provides highgprs facility if needed by + the binary. */ + + lr %r6,%r15 + la %r6,4(%r6) /* Skip the argument counter. */ + +.L11: l %r5,0(%r6) /* Skip the argument vector. */ + la %r6,4(%r6) + ltr %r5,%r5 + jne .L11 + +.L12: l %r5,0(%r6) /* Skip the environment vector. */ + la %r6,4(%r6) + ltr %r5,%r5 + jne .L12 + + /* Obtain the needed values from the auxiliary vector. */ + + lhi %r7,16 /* AT_HWCAP */ + lhi %r8,3 /* AT_PHDR */ + lhi %r9,5 /* AT_PHNUM */ + lhi %r2,4 /* AT_PHENT */ +.L13: l %r5,0(%r6) + clr %r5,%r7 + jne .L15 + l %r10,4(%r6) /* r10 = AT_HWCAP value. */ +.L15: clr %r5,%r8 + jne .L16 + l %r11,4(%r6) /* r11 = AT_PHDR value. */ +.L16: clr %r5,%r9 + jne .L17 + l %r12,4(%r6) /* r12 = AT_PHNUM value. */ +.L17: clr %r5,%r2 + jne .L18 + l %r0,4(%r6) /* r0 = AT_PHENT value. */ +.L18: ltr %r5,%r5 + la %r6,8(%r6) + jnz .L13 + + /* Locate the ELF header by looking for the first PT_LOAD + segment with a p_offset of zero. */ + + lr %r4,%r11 /* Backup AT_PHDR. */ + lhi %r7,1 /* PT_LOAD id */ + lhi %r8,0 +.L19: cl %r7,0(%r4) /* p_type == PT_LOAD? */ + jne .L20 + cl %r8,4(%r4) /* p_offset == 0? */ + jne .L20 + l %r9,8(%r4) /* r9 = p_vaddr <- ELF header address */ + j .L24 +.L20: alr %r4,%r0 /* r4 += AT_PHENT value */ + brct %r12,.L19 + + j .+2 /* Trap, there must be such a phdr. */ + +.L24: lr %r4,%r11 /* Backup AT_PHDR. */ + lhi %r2,6 /* PT_PHDR id */ +.L23: cl %r2,0(%r4) + jne .L22 + l %r3,8(%r4) /* r3 = PT_PHDR p_vaddr */ + j .L25 +.L22: alr %r4,%r0 /* r4 += AT_PHENT value */ + brct %r12,.L23 + + ltr %r9,%r9 /* Load address == 0? */ + jz .L14 /* No checking for PIE without PT_PHDR. */ + j .L21 + +.L25: clr %r3,%r11 /* PT_PHDR p_vaddr == AT_PHDR? */ + je .L21 + lr %r9,%r11 + slr %r9,%r3 /* elf_header_addr = AT_PHDR - PT_PHDR.p_vaddr */ + +.L21: l %r5,36(%r9) /* Load the e_flags field. */ + tml %r5,1 + jz .L14 /* Binary does not require highgprs facility. */ + + tml %r10,512 /* Check the AT_HWCAP value. */ + jz 2 /* Trap if no highgprs facility available. */ +.L14: + /* Setup pointer to literal pool of _start */ basr %r13,0 .L0: ahi %r13,.Llit-.L0 |