source: bootcd/isolinux/syslinux-6.03/gnu-efi/gnu-efi-3.0/gnuefi/reloc_ia64.S

/* reloc_ia64.S - position independent IA-64 ELF shared object relocator
   Copyright (C) 1999 Hewlett-Packard Co.
        Contributed by David Mosberger <davidm@hpl.hp.com>.

    All rights reserved.

    Redistribution and use in source and binary forms, with or without
    modification, are permitted provided that the following conditions
    are met:

    * Redistributions of source code must retain the above copyright
      notice, this list of conditions and the following disclaimer.
    * Redistributions in binary form must reproduce the above
      copyright notice, this list of conditions and the following
      disclaimer in the documentation and/or other materials
      provided with the distribution.
    * Neither the name of Hewlett-Packard Co. nor the names of its
      contributors may be used to endorse or promote products derived
      from this software without specific prior written permission.

    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
    CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
    INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
    MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
    DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS
    BE LIABLE FOR ANYDIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
    OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
    PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
    PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
    THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR
    TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
    THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
    SUCH DAMAGE.
*/

/*
 * This is written in assembly because the entire code needs to be position
 * independent.  Note that the compiler does not generate code that's position
 * independent by itself because it relies on the global offset table being
 * relocated.
 */
        .text
        .psr abi64
        .psr lsb
        .lsb

/*
 * This constant determines how many R_IA64_FPTR64LSB relocations we
 * can deal with.  If you get EFI_BUFFER_TOO_SMALL errors, you may
 * need to increase this number.
 */
#define MAX_FUNCTION_DESCRIPTORS        750

#define ST_VALUE_OFF    8               /* offset of st_value in elf sym */

#define EFI_SUCCESS             0
#define EFI_LOAD_ERROR          1
#define EFI_BUFFER_TOO_SMALL    5

#define DT_NULL         0               /* Marks end of dynamic section */
#define DT_RELA         7               /* Address of Rela relocs */
#define DT_RELASZ       8               /* Total size of Rela relocs */
#define DT_RELAENT      9               /* Size of one Rela reloc */
#define DT_SYMTAB       6               /* Address of symbol table */
#define DT_SYMENT       11              /* Size of one symbol table entry */

#define R_IA64_NONE             0
#define R_IA64_REL64MSB         0x6e
#define R_IA64_REL64LSB         0x6f
#define R_IA64_DIR64MSB         0x26
#define R_IA64_DIR64LSB         0x27
#define R_IA64_FPTR64MSB        0x46
#define R_IA64_FPTR64LSB        0x47

#define ldbase  in0     /* load address (address of .text) */
#define dyn     in1     /* address of _DYNAMIC */

#define d_tag   r16
#define d_val   r17
#define rela    r18
#define relasz  r19
#define relaent r20
#define addr    r21
#define r_info  r22
#define r_offset r23
#define r_addend r24
#define r_type  r25
#define r_sym   r25     /* alias of r_type ! */
#define fptr    r26
#define fptr_limit r27
#define symtab  f8
#define syment  f9
#define ftmp    f10

#define target  r16
#define val     r17

#define NLOC    0

#define Pnull           p6
#define Prela           p7
#define Prelasz         p8
#define Prelaent        p9
#define Psymtab         p10
#define Psyment         p11

#define Pnone           p6
#define Prel            p7
#define Pfptr           p8

#define Pmore           p6

#define Poom            p6      /* out-of-memory */

        .global _relocate
        .proc _relocate
_relocate:
        alloc r2=ar.pfs,2,0,0,0
        movl    fptr = @gprel(fptr_mem_base)
        ;;
        add     fptr = fptr, gp
        movl    fptr_limit = @gprel(fptr_mem_limit)
        ;;
        add     fptr_limit = fptr_limit, gp

search_dynamic:
        ld8     d_tag = [dyn],8
        ;;
        ld8     d_val = [dyn],8
        cmp.eq  Pnull,p0 = DT_NULL,d_tag
(Pnull) br.cond.sptk.few apply_relocs
        cmp.eq  Prela,p0 = DT_RELA,d_tag
        cmp.eq  Prelasz,p0 = DT_RELASZ,d_tag
        cmp.eq  Psymtab,p0 = DT_SYMTAB,d_tag
        cmp.eq  Psyment,p0 = DT_SYMENT,d_tag
        cmp.eq  Prelaent,p0 = DT_RELAENT,d_tag
        ;;
(Prela) add rela = d_val, ldbase
(Prelasz) mov relasz = d_val
(Prelaent) mov relaent = d_val
(Psymtab) add val = d_val, ldbase
        ;;
(Psyment) setf.sig syment = d_val
        ;;
(Psymtab) setf.sig symtab = val
        br.sptk.few search_dynamic

apply_loop:
        ld8     r_offset = [rela]
        add     addr = 8,rela
        sub     relasz = relasz,relaent
        ;;

        ld8     r_info = [addr],8
        ;;
        ld8     r_addend = [addr]
        add     target = ldbase, r_offset

        add     rela = rela,relaent
        extr.u  r_type = r_info, 0, 32
        ;;
        cmp.eq  Pnone,p0 = R_IA64_NONE,r_type
        cmp.eq  Prel,p0 = R_IA64_REL64LSB,r_type
        cmp.eq  Pfptr,p0 = R_IA64_FPTR64LSB,r_type
(Prel)  br.cond.sptk.few apply_REL64
        ;;
        cmp.eq  Prel,p0 = R_IA64_DIR64LSB,r_type // treat DIR64 just like REL64

(Pnone) br.cond.sptk.few apply_relocs
(Prel)  br.cond.sptk.few apply_REL64
(Pfptr) br.cond.sptk.few apply_FPTR64

        mov     r8 = EFI_LOAD_ERROR
        br.ret.sptk.few rp

apply_relocs:
        cmp.ltu Pmore,p0=0,relasz
(Pmore) br.cond.sptk.few apply_loop

        mov     r8 = EFI_SUCCESS
        br.ret.sptk.few rp

apply_REL64:
        ld8 val = [target]
        ;;
        add val = val,ldbase
        ;;
        st8 [target] = val
        br.cond.sptk.few apply_relocs

        // FPTR relocs are a bit more interesting: we need to lookup
        // the symbol's value in symtab, allocate 16 bytes of memory,
        // store the value in [target] in the first and the gp in the
        // second dword.
apply_FPTR64:
        st8     [target] = fptr
        extr.u  r_sym = r_info,32,32
        add     target = 8,fptr
        ;;

        setf.sig ftmp = r_sym
        mov     r8=EFI_BUFFER_TOO_SMALL
        ;;
        cmp.geu Poom,p0 = fptr,fptr_limit

        xma.lu  ftmp = ftmp,syment,symtab
(Poom)  br.ret.sptk.few rp
        ;;
        getf.sig addr = ftmp
        st8     [target] = gp
        ;;
        add     addr = ST_VALUE_OFF, addr
        ;;
        ld8     val = [addr]
        ;;
        add     val = val,ldbase
        ;;
        st8     [fptr] = val,16
        br.cond.sptk.few apply_relocs

        .endp _relocate

        .data
        .align 16
fptr_mem_base:
        .space  MAX_FUNCTION_DESCRIPTORS*16
fptr_mem_limit: