147 lines
5.1 KiB
ArmAsm
147 lines
5.1 KiB
ArmAsm
/*
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Copyright Oliver Kowalke 2009.
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Distributed under the Boost Software License, Version 1.0.
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(See accompanying file LICENSE_1_0.txt or copy at
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http://www.boost.org/LICENSE_1_0.txt)
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*/
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/*******************************************************
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* *
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* ------------------------------------------------- *
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* | 0 | 4 | 8 | 12 | 16 | 20 | 24 | 28 | *
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* ------------------------------------------------- *
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* |bchai|hiddn| fpscr | PC | CR | R14 | R15 | *
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* ------------------------------------------------- *
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* ------------------------------------------------- *
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* | 32 | 36 | 40 | 44 | 48 | 52 | 56 | 60 | *
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* ------------------------------------------------- *
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* | R16 | R17 | R18 | R19 | R20 | R21 | R22 | R23 | *
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* ------------------------------------------------- *
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* ------------------------------------------------- *
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* | 64 | 68 | 72 | 76 | 80 | 84 | 88 | 92 | *
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* ------------------------------------------------- *
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* | R24 | R25 | R26 | R27 | R28 | R29 | R30 | R31 | *
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* ------------------------------------------------- *
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* ------------------------------------------------- *
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* | 96 | 100 | 104 | 108 | 112 | 116 | 120 | 124 | *
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* ------------------------------------------------- *
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* | F14 | F15 | F16 | F17 | *
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* ------------------------------------------------- *
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* ------------------------------------------------- *
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* | 128 | 132 | 136 | 140 | 144 | 148 | 152 | 156 | *
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* ------------------------------------------------- *
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* | F18 | F19 | F20 | F21 | *
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* ------------------------------------------------- *
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* ------------------------------------------------- *
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* | 160 | 164 | 168 | 172 | 176 | 180 | 184 | 188 | *
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* ------------------------------------------------- *
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* | F22 | F23 | F24 | F25 | *
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* ------------------------------------------------- *
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* ------------------------------------------------- *
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* | 192 | 196 | 200 | 204 | 208 | 212 | 216 | 220 | *
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* ------------------------------------------------- *
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* | F26 | F27 | F28 | F29 | *
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* ------------------------------------------------- *
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* ------------------------|------------ *
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* | 224 | 228 | 232 | 236 | 240 | 244 | *
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* ------------------------|------------ *
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* | F30 | F31 |bchai| LR | *
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* ------------------------|------------ *
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* *
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*******************************************************/
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.file "make_ppc32_sysv_elf_gas.S"
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.text
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.globl make_fcontext
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.align 2
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.type make_fcontext,@function
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make_fcontext:
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# save return address into R6
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mflr %r6
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# first arg of make_fcontext() == top address of context-function
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# shift address in R3 to lower 16 byte boundary
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clrrwi %r3, %r3, 4
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# reserve space on context-stack, including 16 bytes of linkage
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# and parameter area + 240 bytes of context-data (R1 % 16 == 0)
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subi %r3, %r3, 16 + 240
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# third arg of make_fcontext() == address of context-function
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#ifdef __linux__
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# save context-function as PC
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stw %r5, 16(%r3)
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#else
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# save context-function for trampoline
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stw %r5, 248(%r3)
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#endif
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# set back-chain to zero
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li %r0, 0
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stw %r0, 240(%r3)
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# copy FPSCR to new context
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mffs %f0
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stfd %f0, 8(%r3)
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#ifdef __linux__
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# set hidden pointer for returning transfer_t
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la %r0, 248(%r3)
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stw %r0, 4(%r3)
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#endif
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# load address of label 1 into R4
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bl 1f
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1: mflr %r4
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#ifndef __linux__
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# compute abs address of trampoline, use as PC
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addi %r7, %r4, trampoline - 1b
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stw %r7, 16(%r3)
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#endif
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# compute abs address of label finish
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addi %r4, %r4, finish - 1b
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# save address of finish as return-address for context-function
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# will be entered after context-function returns
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stw %r4, 244(%r3)
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# restore return address from R6
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mtlr %r6
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blr # return pointer to context-data
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#ifndef __linux__
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trampoline:
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# On systems other than Linux, jump_fcontext is returning the
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# transfer_t in R3:R4, but we need to pass transfer_t * R3 to
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# our context-function.
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lwz %r0, 8(%r1) # address of context-function
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mtctr %r0
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stw %r3, 8(%r1)
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stw %r4, 12(%r1)
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la %r3, 8(%r1) # address of transfer_t
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bctr
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#endif
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finish:
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# Use the secure PLT for _exit(0). If we use the insecure BSS PLT
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# here, then the linker may use the insecure BSS PLT even if the
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# C++ compiler wanted the secure PLT.
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# set R30 for secure PLT, large model
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bl 2f
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2: mflr %r30
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addis %r30, %r30, .Ltoc - 2b@ha
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addi %r30, %r30, .Ltoc - 2b@l
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# call _exit(0) with special addend 0x8000 for large model
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li %r3, 0
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bl _exit + 0x8000@plt
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.size make_fcontext, .-make_fcontext
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/* Provide the GOT pointer for secure PLT, large model. */
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.section .got2,"aw"
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.Ltoc = . + 0x8000
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/* Mark that we don't need executable stack. */
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.section .note.GNU-stack,"",%progbits
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