From d64402737bb104c759b8ac293d915d4cde944340 Mon Sep 17 00:00:00 2001 From: Ariadne Conill Date: Mon, 12 Aug 2024 13:17:41 -0700 Subject: [PATCH] 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. --- arch/loongarch64/defs.h | 10 ++- arch/loongarch64/makecontext.S | 108 --------------------------------- arch/loongarch64/makecontext.c | 61 +++++++++++++++++++ 3 files changed, 69 insertions(+), 110 deletions(-) delete mode 100644 arch/loongarch64/makecontext.S create mode 100644 arch/loongarch64/makecontext.c diff --git a/arch/loongarch64/defs.h b/arch/loongarch64/defs.h index 94d014a..74e2dd7 100644 --- a/arch/loongarch64/defs.h +++ b/arch/loongarch64/defs.h @@ -45,11 +45,17 @@ /* frame pointer is actually $22 */ #define REG_FP (22) +/* $s0 is $23 */ +#define REG_S0 (23) + +/* $ra is $1 */ +#define REG_RA (1) + /* offset to mc_gregs in ucontext_t */ -#define MCONTEXT_GREGS (48) +#define MCONTEXT_GREGS (184) /* offset to PC in ucontext_t */ -#define MCONTEXT_PC (40) +#define MCONTEXT_PC (176) /* offset to uc_link in ucontext_t */ #define UCONTEXT_UC_LINK (8) diff --git a/arch/loongarch64/makecontext.S b/arch/loongarch64/makecontext.S deleted file mode 100644 index f0f95b5..0000000 --- a/arch/loongarch64/makecontext.S +++ /dev/null @@ -1,108 +0,0 @@ -/* - * Copyright (c) 2021 Peng Fan - * - * Permission to use, copy, modify, and/or distribute this software for any - * purpose with or without fee is hereby granted, provided that the above - * copyright notice and this permission notice appear in all copies. - * - * This software is provided 'as is' and without any warranty, express or - * implied. In no event shall the authors be liable for any damages arising - * from the use of this software. - */ - -#include "defs.h" - -#define LOCALSZ (6) - -#define A3_OFF (FRAMESZ - (5 * REG_SZ)) -#define A4_OFF (FRAMESZ - (4 * REG_SZ)) -#define A5_OFF (FRAMESZ - (3 * REG_SZ)) -#define A6_OFF (FRAMESZ - (2 * REG_SZ)) -#define A7_OFF (FRAMESZ - (1 * REG_SZ)) - -ALIAS(makecontext, libucontext_makecontext) - -FUNC(libucontext_makecontext) - PUSH_FRAME(libucontext_makecontext) - - move $t5, $a0 - move $t4, $a1 - - /* store $a3 through $a7 to the stack frame. */ - st.d $a3, $sp, A3_OFF - st.d $a4, $sp, A4_OFF - st.d $a5, $sp, A5_OFF - st.d $a6, $sp, A6_OFF - st.d $a7, $sp, A7_OFF - - /* set $zero in the mcontext to 1. */ - addi.d $a0, $zero, 1 - st.d $a0, $t5, REG_OFFSET(0) - - /* ensure the stack is aligned on a quad-word boundary. */ - ld.d $t0, $t5, UCONTEXT_STACK_PTR - ld.d $t2, $t5, UCONTEXT_STACK_SIZE - /* the third argument(from zero), that's the first argument of func() */ - addi.d $t1, $sp, A3_OFF - add.d $t0, $t0, $t2 - - addi.d $t7, $zero, ALMASK - and $t0, $t0, $t7 - - /* number of args */ - beq $a2, $zero, no_more_arguments - bltu $a2, $zero, no_more_arguments - - /* store register arguments. */ - addi.d $t2, $t5, MCONTEXT_GREGS + (4 * REG_SZ) - move $t3, $zero - -store_register_arg: - addi.d $t3, $t3, 1 - ld.d $a1, $t1, 0 - addi.d $t1, $t1, REG_SZ - st.d $a1, $t2, 0 - addi.d $t2, $t2, REG_SZ - addi.d $t6, $zero, 8 - bltu $t3, $t6, store_register_arg - bgeu $t3, $a2, no_more_arguments - - /* make room for stack arguments. */ - sub.d $t2, $a2, $t3 - - addi.d $t6, $zero, 3 - sll.d $t2, $t2, $t6 - - sub.d $t0, $t0, $t2 - - addi.d $t6, $zero, ALMASK - and $t0, $t0, $t6 - - /* store stack arguments. */ - move $t2, $t0 - -store_stack_arg: - addi.d $t3, $t3, 1 - ld.d $a1, $t1, 0 - addi.d $t1, $t1, REG_SZ - st.d $a1, $t2, 0 - addi.d $t2, $t2, REG_SZ - bltu $t3, $a2, store_stack_arg - -no_more_arguments: - /* trampoline setup. */ - la.got $t8, libucontext_trampoline - - ld.d $a1, $t5, UCONTEXT_UC_LINK - st.d $a1, $t5, REG_OFFSET(23) - - st.d $t0, $t5, REG_OFFSET(3) - - st.d $t8, $t5, REG_OFFSET(1) - - st.d $t4, $t5, MCONTEXT_PC - - POP_FRAME(libucontext_makecontext) - - jr $ra -END(libucontext_makecontext) diff --git a/arch/loongarch64/makecontext.c b/arch/loongarch64/makecontext.c new file mode 100644 index 0000000..1800529 --- /dev/null +++ b/arch/loongarch64/makecontext.c @@ -0,0 +1,61 @@ +/* + * Copyright (c) 2024 Ariadne Conill + * + * Permission to use, copy, modify, and/or distribute this software for any + * purpose with or without fee is hereby granted, provided that the above + * copyright notice and this permission notice appear in all copies. + * + * This software is provided 'as is' and without any warranty, express or + * implied. In no event shall the authors be liable for any damages arising + * from the use of this software. + */ + +#include +#include +#include +#include +#include +#include "defs.h" +#include + + +extern void libucontext_trampoline(void); + + +void +libucontext_makecontext(libucontext_ucontext_t *ucp, void (*func)(void), int argc, ...) +{ + libucontext_greg_t *sp, *regp; + va_list va; + int i; + + /* set up and align the stack. */ + sp = (libucontext_greg_t *) ((uintptr_t) ucp->uc_stack.ss_sp + ucp->uc_stack.ss_size); + sp -= argc < 8 ? 0 : argc - 8; + sp = (libucontext_greg_t *) (((uintptr_t) sp & -16L)); + + /* set up the ucontext structure */ + ucp->uc_mcontext.__gregs[REG_RA] = (libucontext_greg_t) libucontext_trampoline; + ucp->uc_mcontext.__gregs[REG_S0] = (libucontext_greg_t) ucp->uc_link; + ucp->uc_mcontext.__gregs[REG_SP] = (libucontext_greg_t) sp; + ucp->uc_mcontext.__pc = (libucontext_greg_t) func; + + va_start(va, argc); + + /* first 8 args go in $a0 through $a7. */ + regp = &(ucp->uc_mcontext.__gregs[REG_A0]); + + for (i = 0; (i < argc && i < 8); i++) + *regp++ = va_arg (va, libucontext_greg_t); + + /* remainder overflows into stack */ + for (; i < argc; i++) + *sp++ = va_arg (va, libucontext_greg_t); + + va_end(va); +} + +#ifdef EXPORT_UNPREFIXED +extern __typeof(libucontext_makecontext) makecontext __attribute__((weak, __alias__("libucontext_makecontext"))); +extern __typeof(libucontext_makecontext) __makecontext __attribute__((weak, __alias__("libucontext_makecontext"))); +#endif