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Merge pull request #251 from cjeker/sparc64_asm_support
Implement the fcontext asm for sparc64
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‎build/Jamfile.v2

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@@ -519,6 +519,30 @@ alias asm_sources
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<toolset>gcc
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;
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# SPARC64
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# SPARC64/SYSV/ELF
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alias asm_sources
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: asm/make_sparc64_sysv_elf_gas.S
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asm/jump_sparc64_sysv_elf_gas.S
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asm/ontop_sparc64_sysv_elf_gas.S
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: <abi>sysv
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<address-model>64
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<architecture>sparc
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<binary-format>elf
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<toolset>clang
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;
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alias asm_sources
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: asm/make_sparc64_sysv_elf_gas.S
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asm/jump_sparc64_sysv_elf_gas.S
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asm/ontop_sparc64_sysv_elf_gas.S
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: <abi>sysv
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<address-model>64
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<architecture>sparc
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<binary-format>elf
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<toolset>gcc
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;
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# S390X
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# S390X/SYSV/ELF
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alias asm_sources

‎src/asm/jump_sparc64_sysv_elf_gas.S

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/*
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Copyright Claudio Jeker 2024
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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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* typedef void* fcontext_t;
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*
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* struct transfer_t {
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* fcontext_t fctx;
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* void * data;
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* };
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*
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* transfer_t jump_fcontext(fcontext_t const to, void *vp);
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*/
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#define CC64FSZ 176
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#define BIAS 2047
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#define SP 128
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#define I7 136
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.file "jump_sparc64_sysv_elf_gas.S"
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.text
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.align 4
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.global jump_fcontext
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.type jump_fcontext, %function
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jump_fcontext:
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# prepare stack
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save %sp, -CC64FSZ, %sp
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# store framepointer and return address in slots reserved
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# for arguments
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stx %fp, [%sp + BIAS + SP]
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stx %i7, [%sp + BIAS + I7]
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mov %sp, %o0
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# force flush register windows to stack and with that save context
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flushw
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# get SP (pointing to new context-data) from %i0 param
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mov %i0, %sp
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# load framepointer and return address from context
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ldx [%sp + BIAS + SP], %fp
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ldx [%sp + BIAS + I7], %i7
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ret
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restore %o0, %g0, %o0
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# restore old %sp (pointing to old context-data) in %o0
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# *data stored in %o1 was not modified
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.size jump_fcontext,.-jump_fcontext
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# Mark that we don't need executable stack.
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.section .note.GNU-stack,"",%progbits

‎src/asm/make_sparc64_sysv_elf_gas.S

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/*
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Copyright Claudio Jeker 2024
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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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* fcontext_t *make_fcontext(void *sp, size_t size, void (*fn)(transfer_t));
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*/
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#define CC64FSZ 176
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#define BIAS 2047
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#define FP 112
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#define SP 128
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#define I7 136
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.file "make_sparc64_sysv_elf_gas.S"
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.text
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.align 4
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.global make_fcontext
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.type make_fcontext, %function
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make_fcontext:
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save %sp, -CC64FSZ, %sp
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# shift address in %i0 (allocated stack) to lower 16 byte boundary
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and %i0, -0xf, %i0
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# reserve space for two frames on the stack
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# the first frame is for the call the second one holds the data
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# for jump_fcontext
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sub %i0, 2 * CC64FSZ, %i0
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# third argument of make_fcontext() is the context-function to call
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# store it in the first stack frame, also clear %fp there to indicate
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# the end of the stack.
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stx %i2, [%i0 + CC64FSZ + I7]
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stx %g0, [%i0 + CC64FSZ + FP]
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# On OpenBSD stackghost prevents overriding the return address on
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# a stack frame. So this code uses an extra trampoline to load
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# to call the context-function and then do the _exit(0) dance.
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# Extract the full address of the trampoline via pc relative addressing
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1:
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rd %pc, %l0
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add %l0, (trampoline - 1b - 8), %l0
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stx %l0, [%i0 + I7]
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# Save framepointer to first stack frame but first substract the BIAS
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add %i0, CC64FSZ - BIAS, %l0
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stx %l0, [%i0 + SP]
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# Return context-data which is also includes the BIAS
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ret
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restore %i0, -BIAS, %o0
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trampoline:
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ldx [%sp + BIAS + I7], %l0
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# no need to setup transfer_t, already in %o0 and %o1
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jmpl %l0, %o7
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nop
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call _exit
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clr %o0
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unimp
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.size make_fcontext,.-make_fcontext
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# Mark that we don't need executable stack.
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.section .note.GNU-stack,"",%progbits

‎src/asm/ontop_sparc64_sysv_elf_gas.S

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/*
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Copyright Claudio Jeker 2024
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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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* transfer_t ontop_fcontext(fcontext_t const to, void *vp, transfer_t (*fn)(transfer_t));
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*/
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#define CC64FSZ 176
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#define BIAS 2047
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#define SP 128
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#define I7 136
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.file "ontop_sparc64_sysv_elf_gas.S"
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.text
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.align 4
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.global ontop_fcontext
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.type ontop_fcontext, %function
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ontop_fcontext:
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# prepare stack
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save %sp, -CC64FSZ, %sp
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# store framepointer and return address in slots reserved
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# for arguments
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stx %fp, [%sp + BIAS + SP]
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stx %i7, [%sp + BIAS + I7]
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mov %sp, %o0
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# force flush register windows to stack and with that save context
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flushw
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# get SP (pointing to new context-data) from %i0 param
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mov %i0, %sp
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# load framepointer and return address from context
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ldx [%sp + BIAS + SP], %fp
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ldx [%sp + BIAS + I7], %i7
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# ontop_fcontext requires to directly call a function on top of the
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# current frame so restore register window before doing the jump
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# to the context function which then is in %o2. Do not clobber
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# %o7 in the jump so that (*fn)() returns to that address.
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restore %o0, %g0, %o0
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# restore old %sp (pointing to old context-data) in %o0
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# *data stored in %o1 was not modified
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jmpl %o2, %g0
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nop
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.size jump_fcontext,.-jump_fcontext
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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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