forked from ariadne/libucontext
loongarch64: rewrite makecontext in C
also fix MCONTEXT_PC and MCONTEXT_GREGS so they actually read and write to/from the correct addresses in the ucontext structure.master
Ariadne Conill
parent
c3d26b7940
commit
d64402737b
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@ -45,11 +45,17 @@
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/* frame pointer is actually $22 */
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#define REG_FP (22)
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/* $s0 is $23 */
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#define REG_S0 (23)
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/* $ra is $1 */
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#define REG_RA (1)
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/* offset to mc_gregs in ucontext_t */
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#define MCONTEXT_GREGS (48)
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#define MCONTEXT_GREGS (184)
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/* offset to PC in ucontext_t */
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#define MCONTEXT_PC (40)
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#define MCONTEXT_PC (176)
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/* offset to uc_link in ucontext_t */
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#define UCONTEXT_UC_LINK (8)
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@ -1,108 +0,0 @@
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/*
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* Copyright (c) 2021 Peng Fan <fanpeng@loongson.cn>
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*
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* Permission to use, copy, modify, and/or distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* This software is provided 'as is' and without any warranty, express or
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* implied. In no event shall the authors be liable for any damages arising
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* from the use of this software.
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*/
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#include "defs.h"
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#define LOCALSZ (6)
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#define A3_OFF (FRAMESZ - (5 * REG_SZ))
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#define A4_OFF (FRAMESZ - (4 * REG_SZ))
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#define A5_OFF (FRAMESZ - (3 * REG_SZ))
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#define A6_OFF (FRAMESZ - (2 * REG_SZ))
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#define A7_OFF (FRAMESZ - (1 * REG_SZ))
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ALIAS(makecontext, libucontext_makecontext)
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FUNC(libucontext_makecontext)
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PUSH_FRAME(libucontext_makecontext)
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move $t5, $a0
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move $t4, $a1
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/* store $a3 through $a7 to the stack frame. */
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st.d $a3, $sp, A3_OFF
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st.d $a4, $sp, A4_OFF
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st.d $a5, $sp, A5_OFF
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st.d $a6, $sp, A6_OFF
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st.d $a7, $sp, A7_OFF
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/* set $zero in the mcontext to 1. */
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addi.d $a0, $zero, 1
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st.d $a0, $t5, REG_OFFSET(0)
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/* ensure the stack is aligned on a quad-word boundary. */
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ld.d $t0, $t5, UCONTEXT_STACK_PTR
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ld.d $t2, $t5, UCONTEXT_STACK_SIZE
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/* the third argument(from zero), that's the first argument of func() */
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addi.d $t1, $sp, A3_OFF
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add.d $t0, $t0, $t2
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addi.d $t7, $zero, ALMASK
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and $t0, $t0, $t7
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/* number of args */
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beq $a2, $zero, no_more_arguments
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bltu $a2, $zero, no_more_arguments
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/* store register arguments. */
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addi.d $t2, $t5, MCONTEXT_GREGS + (4 * REG_SZ)
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move $t3, $zero
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store_register_arg:
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addi.d $t3, $t3, 1
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ld.d $a1, $t1, 0
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addi.d $t1, $t1, REG_SZ
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st.d $a1, $t2, 0
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addi.d $t2, $t2, REG_SZ
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addi.d $t6, $zero, 8
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bltu $t3, $t6, store_register_arg
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bgeu $t3, $a2, no_more_arguments
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/* make room for stack arguments. */
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sub.d $t2, $a2, $t3
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addi.d $t6, $zero, 3
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sll.d $t2, $t2, $t6
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sub.d $t0, $t0, $t2
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addi.d $t6, $zero, ALMASK
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and $t0, $t0, $t6
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/* store stack arguments. */
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move $t2, $t0
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store_stack_arg:
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addi.d $t3, $t3, 1
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ld.d $a1, $t1, 0
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addi.d $t1, $t1, REG_SZ
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st.d $a1, $t2, 0
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addi.d $t2, $t2, REG_SZ
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bltu $t3, $a2, store_stack_arg
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no_more_arguments:
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/* trampoline setup. */
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la.got $t8, libucontext_trampoline
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ld.d $a1, $t5, UCONTEXT_UC_LINK
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st.d $a1, $t5, REG_OFFSET(23)
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st.d $t0, $t5, REG_OFFSET(3)
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st.d $t8, $t5, REG_OFFSET(1)
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st.d $t4, $t5, MCONTEXT_PC
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POP_FRAME(libucontext_makecontext)
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jr $ra
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END(libucontext_makecontext)
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@ -0,0 +1,61 @@
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/*
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* Copyright (c) 2024 Ariadne Conill <ariadne@dereferenced.org>
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*
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* Permission to use, copy, modify, and/or distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* This software is provided 'as is' and without any warranty, express or
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* implied. In no event shall the authors be liable for any damages arising
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* from the use of this software.
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*/
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#include <stddef.h>
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#include <stdarg.h>
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#include <string.h>
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#include <stdint.h>
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#include <stdio.h>
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#include "defs.h"
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#include <libucontext/libucontext.h>
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extern void libucontext_trampoline(void);
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void
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libucontext_makecontext(libucontext_ucontext_t *ucp, void (*func)(void), int argc, ...)
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{
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libucontext_greg_t *sp, *regp;
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va_list va;
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int i;
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/* set up and align the stack. */
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sp = (libucontext_greg_t *) ((uintptr_t) ucp->uc_stack.ss_sp + ucp->uc_stack.ss_size);
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sp -= argc < 8 ? 0 : argc - 8;
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sp = (libucontext_greg_t *) (((uintptr_t) sp & -16L));
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/* set up the ucontext structure */
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ucp->uc_mcontext.__gregs[REG_RA] = (libucontext_greg_t) libucontext_trampoline;
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ucp->uc_mcontext.__gregs[REG_S0] = (libucontext_greg_t) ucp->uc_link;
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ucp->uc_mcontext.__gregs[REG_SP] = (libucontext_greg_t) sp;
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ucp->uc_mcontext.__pc = (libucontext_greg_t) func;
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va_start(va, argc);
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/* first 8 args go in $a0 through $a7. */
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regp = &(ucp->uc_mcontext.__gregs[REG_A0]);
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for (i = 0; (i < argc && i < 8); i++)
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*regp++ = va_arg (va, libucontext_greg_t);
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/* remainder overflows into stack */
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for (; i < argc; i++)
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*sp++ = va_arg (va, libucontext_greg_t);
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va_end(va);
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}
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#ifdef EXPORT_UNPREFIXED
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extern __typeof(libucontext_makecontext) makecontext __attribute__((weak, __alias__("libucontext_makecontext")));
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extern __typeof(libucontext_makecontext) __makecontext __attribute__((weak, __alias__("libucontext_makecontext")));
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#endif
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