freebsd-dev/sys/boot/ia64/efi/start.S
Marcel Moolenaar 77de753f65 Improve self-relocation:
o  We don't expect the PLT relocations to follow the .rela section
   anymore. We still assume that PLT relocations are long formed,
o  Document register usage,
o  Improve ILP,
o  Fix the FPTR relocation by creating unique OPDs per function.
   Comparing functions is valid now,
o  The IPLT relocation naturally handles the addend. Deal with it.
   We ignore the addend for FPTR relocations for now. It's not at
   all clear what it means anyway.

Fix ABI misinterpretation:
o  For Elf_Rela relocations, the addend is explicit and should not
   be loaded from the memory address we're relocating. Only do that
   for Elf_Rel relocations (ie the short form).
o  DIR64LSB is not the same as REL64LSB. DIR64LSB applies to a
   symbol (S+A), whereas REL64LSB applies to the base address (BD+A),
2002-04-21 08:49:47 +00:00

405 lines
9.2 KiB
ArmAsm

/*-
* Copyright (c) 2001 Doug Rabson
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. 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.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, 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.
*
* $FreeBSD$
*/
.text
#include <machine/asm.h>
#define EFI_SUCCESS 0
#define EFI_LOAD_ERROR 1
#define EFI_BUFFER_TOO_SMALL 5
#define DT_NULL 0 /* Terminating entry. */
#define DT_NEEDED 1 /* String table offset of a needed shared
library. */
#define DT_PLTRELSZ 2 /* Total size in bytes of PLT relocations. */
#define DT_PLTGOT 3 /* Processor-dependent address. */
#define DT_HASH 4 /* Address of symbol hash table. */
#define DT_STRTAB 5 /* Address of string table. */
#define DT_SYMTAB 6 /* Address of symbol table. */
#define DT_RELA 7 /* Address of ElfNN_Rela relocations. */
#define DT_RELASZ 8 /* Total size of ElfNN_Rela relocations. */
#define DT_RELAENT 9 /* Size of each ElfNN_Rela relocation entry. */
#define DT_STRSZ 10 /* Size of string table. */
#define DT_SYMENT 11 /* Size of each symbol table entry. */
#define DT_INIT 12 /* Address of initialization function. */
#define DT_FINI 13 /* Address of finalization function. */
#define DT_SONAME 14 /* String table offset of shared object
name. */
#define DT_RPATH 15 /* String table offset of library path. */
#define DT_SYMBOLIC 16 /* Indicates "symbolic" linking. */
#define DT_REL 17 /* Address of ElfNN_Rel relocations. */
#define DT_RELSZ 18 /* Total size of ElfNN_Rel relocations. */
#define DT_RELENT 19 /* Size of each ElfNN_Rel relocation. */
#define DT_PLTREL 20 /* Type of relocation used for PLT. */
#define DT_DEBUG 21 /* Reserved (not used). */
#define DT_TEXTREL 22 /* Indicates there may be relocations in
non-writable segments. */
#define DT_JMPREL 23 /* Address of PLT relocations. */
#define DT_COUNT 24 /* Number of defined d_tag values. */
#define R_IA64_NONE 0 /* None */
#define R_IA64_DIR64MSB 0x26 /* word64 MSB S + A */
#define R_IA64_DIR64LSB 0x27 /* word64 LSB S + A */
#define R_IA64_FPTR64MSB 0x46 /* word64 MSB @fptr(S + A) */
#define R_IA64_FPTR64LSB 0x47 /* word64 LSB @fptr(S + A) */
#define R_IA64_REL64MSB 0x6e /* word64 MSB BD + A */
#define R_IA64_REL64LSB 0x6f /* word64 LSB BD + A */
#define R_IA64_IPLTLSB 0x81 /* function descriptor LSB speciaal */
ENTRY(_start, 2)
alloc loc0=ar.pfs,2,3,3,0
mov loc1=rp
movl loc2=@gprel(ImageBase)
;;
add loc2=gp,loc2
;;
mov out0=loc2
mov out1=in1
;;
br.call.sptk.few rp=_reloc // relocate image
cmp.ne p6,p0=EFI_SUCCESS,r8 // did it work?
(p6) br.cond.dpnt.few 9f
mov out0=in0 // image_handle
mov out1=in1 // system_table
br.call.sptk.few rp=efi_main
9:
mov ar.pfs=loc0
mov rp=loc1
;;
br.ret.sptk.few rp
END(_start)
// PLABEL for PE32+
.global _start_plabel
.section .plabel, "a"
.align 16
_start_plabel:
.quad _start
.quad __gp
.previous
// A PE32+ relocation entry for the plabel
.section .reloc, "a"
.long _start_plabel
.long 12
.short (10 << 12) + 0
.short (10 << 12) + 8
.previous
// in0: image base
// in1: system table
//
// XXX Assumes PLT relocations are of type Elf_Rela
//
// r2 = address of fptr_storage
// r3 = address of fptr_storage_end
// r4 = address of first free fptr
//
// r15 = r_offset
// r16 = r_info -OR- d_tag
// r17 = r_addend -OR- d_val (=d_ptr)
// r18 = address of .rela dynamic section
// r19 = size of .rela section
// r20 = size of .rela element (Elf_Rela)
// r21 = address of first PLT relocation
// r22 = size of PLT relocations
// r23 = relocation type
// r24 = address of symbol
// r28 = R_IA64_IPLTLSB
// f8 = address of symbol table
// f9 = size of symtab element
STATIC_ENTRY(_reloc, 2)
alloc loc0=ar.pfs,2,2,0,0
;;
mov loc1=rp
movl r29=@gprel(_DYNAMIC) // find _DYNAMIC etc.
;;
add r15=r29,gp
movl r29=@gprel(fptr_storage)
;;
add r2=r29,gp
movl r29=@gprel(fptr_storage_end)
;;
add r3=r29,gp
mov r4=r2
mov r19=0
mov r22=0
mov r20=24
mov r28=R_IA64_IPLTLSB
;;
1:
ld8 r16=[r15],8 // read r15->d_tag
;;
ld8 r17=[r15],8 // and r15->d_val
;;
cmp.eq p6,p0=DT_NULL,r16 // done?
(p6) br.cond.dpnt.few 2f
;;
cmp.eq p6,p0=DT_RELA,r16 // rela section?
;;
(p6) add r18=r17,in0
cmp.eq p6,p0=DT_RELASZ,r16 // rela section size?
;;
(p6) mov r19=r17
cmp.eq p6,p0=DT_RELAENT,r16 // rela entry size?
;;
(p6) mov r20=r17
cmp.eq p6,p0=DT_JMPREL,r16 // PLT relocs?
;;
(p6) add r21=r17,in0
cmp.eq p6,p0=DT_PLTRELSZ,r16 // PLT relocs size?
;;
(p6) mov r22=r17
cmp.eq p6,p0=DT_SYMTAB,r16 // symbol table?
;;
(p6) add r29=r17,in0
;;
(p6) setf.sig f8=r29
cmp.eq p6,p0=DT_SYMENT,r16 // symbol entry size?
;;
(p6) setf.sig f9=r17
br.dptk 1b
2:
cmp.lt p6,p0=0,r19
(p6) br.cond.dptk 3f
;;
mov r19=r22
mov r18=r21
mov r21=0
mov r22=0
;;
cmp.lt p6,p0=0,r19
(p6) br.cond.dptk 3f
;;
mov r8=EFI_SUCCESS
br.dptk 9f
3:
ld8 r29=[r18],8 // read r_offset
;;
ld8 r16=[r18],8 // read r_info
add r15=r29,in0 // relocate r_offset
;;
ld8 r17=[r18],8 // read r_addend
sub r19=r19,r20 // update relasz
extr.u r23=r16,0,32 // ELF64_R_TYPE(r16)
;;
cmp.eq p6,p0=R_IA64_NONE,r23
(p6) br.cond.dpnt.few 2b
;;
cmp.eq p6,p0=R_IA64_REL64LSB,r23
(p6) br.cond.dptk.few 4f
;;
extr.u r29=r16,32,32 // ELF64_R_SYM(r16)
;;
setf.sig f10=r29 // so we can multiply
;;
xma.lu f10=f10,f9,f8 // f10=symtab + r_sym*syment
;;
getf.sig r29=f10
;;
add r29=8,r29 // address of st_value
;;
ld8 r29=[r29] // read symbol value
;;
add r24=r29,in0 // relocate symbol value
;;
cmp.eq p6,p0=R_IA64_DIR64LSB,r23
(p6) br.cond.dptk.few 5f
;;
cmp.eq p6,p0=R_IA64_FPTR64LSB,r23
(p6) br.cond.dptk.few 6f
;;
cmp.ne p6,p0=r28,r23 // IPLTLSB
(p6) br.cond.dptk.few 2b
// IPLTLSB
add r29=r24,r17 // S + A
;;
st8 [r15]=r29,8 // fdesc:FP
;;
st8 [r15]=gp // fdesc:GP
br.cond.sptk.few 2b
// REL64LSB
4:
add r29=in0,r17 // BD + A
;;
st8 [r15]=r29 // word64
br.cond.sptk.few 2b
// DIR64LSB
5:
add r29=r24,r17 // S + A
;;
st8 [r15]=r29 // word64
br.cond.sptk.few 2b
6:
mov r29=r2 // FPTR64LSB
;;
7:
cmp.geu p6,p0=r29,r4 // end of fptrs?
(p6) br.cond.dpnt.few 8f // can't find existing fptr
ld8 r17=[r29] // read function from fptr
;;
cmp.eq p6,p0=r24,r17 // same function?
;;
(p6) st8 [r15]=r29 // reuse fptr
(p6) br.cond.sptk.few 2b // done
add r29=16,r29 // next fptr
br.sptk.few 7b
8:
mov r8=EFI_BUFFER_TOO_SMALL // failure return value
cmp.geu p6,p0=r4,r3 // space left?
(p6) br.cond.dpnt.few 9f // bail out
st8 [r15]=r4 // install fptr
;;
st8 [r4]=r24,8 // write fptr address
;;
st8 [r4]=gp,8 // write fptr gp
br.cond.sptk.few 2b
9:
mov ar.pfs=loc0
mov rp=loc1
;;
br.ret.sptk.few rp
END(_reloc)
// in0: system table
// in1: character
ENTRY(_putchar, 2)
alloc loc0=ar.pfs,2,3,2,0
mov loc1=rp
mov loc2=gp
add sp=-32,sp
;;
add r14=64,in0 // r14 = &in1->ConOut
;;
ld8 r14=[r14] // r14 = in1->ConOut
;;
add r15=8,r14 // r15 = &r14->OutputString
mov out0=r14
mov out1=sp
mov r16=sp
;;
ld8 r15=[r15] // r15 = r14->OutputString
st2 [r16]=in1,2 // write character
;;
st2 [r16]=r0 // terminate
ld8 r17=[r15],8 // function address
;;
ld8 gp=[r15] // function gp
mov b6=r17 // transfer to branch register
;;
br.call.sptk.few rp=b6 // call function
;;
mov gp=loc2 // restore gp
mov ar.pfs=loc0
mov rp=loc1
add sp=32,sp
;;
br.ret.sptk.few rp
END(_putchar)
// in0: system table
// in1: string
ENTRY(_puts, 2)
alloc loc0=ar.pfs,3,2,2,0
mov loc1=rp
;;
mov out0=in0
;;
1: ld1 out1=[in1],1
;;
cmp.eq p6,p0=r0,out1
(p6) br.cond.dpnt.few 9f
;;
br.call.sptk.few rp=_putchar
;;
br.cond.sptk.few 1b
9:
mov ar.pfs=loc0
mov rp=loc1
;;
br.ret.sptk.few rp
END(_puts)
// in0: system table
// in1: number
ENTRY(_puthex, 2)
alloc loc0=ar.pfs,2,3,2,0
mov loc1=rp
mov loc2=ar.lc
;;
mov out0=in0
mov ar.lc=15
;;
1: extr.u out1=in1,60,4
;;
cmp.leu p6,p7=10,out1
;;
(p6) add out1='a'-10,out1
(p7) add out1='0',out1
dep.z in1=in1,4,60
;;
br.call.sptk.few rp=_putchar
;;
br.cloop.sptk.few 1b
;;
mov out1='\r'
;;
br.call.sptk.few rp=_putchar
;;
mov out1='\n'
;;
br.call.sptk.few rp=_putchar
;;
9:
mov ar.pfs=loc0
mov rp=loc1
mov ar.lc=loc2
;;
br.ret.sptk.few rp
END(_puthex)
.data
.align 16
fptr_storage:
.space 1024*16 // XXX
fptr_storage_end: