From 7760ccced8883571bc00b42ed29384381d1413a5 Mon Sep 17 00:00:00 2001 From: Andreas Krebbel Date: Fri, 15 Jan 2010 09:10:44 -0800 Subject: [PATCH] /390: Add runtime check for the highgprs kernel feature. --- elf/elf.h | 6 +++ sysdeps/s390/s390-32/dl-machine.h | 7 ++++ sysdeps/s390/s390-32/elf/start.S | 82 +++++++++++++++++++++++++++++++++++++++ 3 files changed, 95 insertions(+) diff --git a/elf/elf.h b/elf/elf.h index 1bc8ef3..8af7c17 100644 --- a/elf/elf.h +++ b/elf/elf.h @@ -2493,6 +2493,12 @@ typedef Elf32_Addr Elf32_Conflict; /* Keep this the last entry. */ #define R_SH_NUM 256 +/* S/390 specific definitions. */ + +/* Valid values for the e_flags field. */ + +#define EF_S390_HIGH_GPRS 0x00000001 /* High GPRs kernel facility needed. */ + /* Additional s390 relocs */ #define R_390_NONE 0 /* No reloc. */ diff --git a/sysdeps/s390/s390-32/dl-machine.h b/sysdeps/s390/s390-32/dl-machine.h index 251a5f6..415b388 100644 --- a/sysdeps/s390/s390-32/dl-machine.h +++ b/sysdeps/s390/s390-32/dl-machine.h @@ -27,6 +27,7 @@ #include #include #include +#include /* This is an older, now obsolete value. */ #define EM_S390_OLD 0xA390 @@ -35,6 +36,12 @@ static inline int elf_machine_matches_host (const Elf32_Ehdr *ehdr) { + /* Check if the kernel provides the high gpr facility if needed by + the binary. */ + if ((ehdr->e_flags & EF_S390_HIGH_GPRS) + && !(GLRO (dl_hwcap) & HWCAP_S390_HIGH_GPRS)) + return 0; + return (ehdr->e_machine == EM_S390 || ehdr->e_machine == EM_S390_OLD) && ehdr->e_ident[EI_CLASS] == ELFCLASS32; } diff --git a/sysdeps/s390/s390-32/elf/start.S b/sysdeps/s390/s390-32/elf/start.S index f729010..066f7f0 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 -- 2.7.4