From f231ba278e7820f5b73cde16f17f227118d9bafc Mon Sep 17 00:00:00 2001 From: Natanael Copa Date: Mon, 29 Oct 2012 14:33:26 +0000 Subject: [PATCH 2/2] libc/sysdeps: add {get,make,set,swap}context for x86_64 --- libc/sysdeps/linux/x86_64/Makefile.arch | 39 +++++++++ libc/sysdeps/linux/x86_64/__start_context.S | 49 +++++++++++ libc/sysdeps/linux/x86_64/getcontext.S | 88 ++++++++++++++++++++ libc/sysdeps/linux/x86_64/makecontext.c | 121 ++++++++++++++++++++++++++++ libc/sysdeps/linux/x86_64/setcontext.S | 103 +++++++++++++++++++++++ libc/sysdeps/linux/x86_64/swapcontext.S | 121 ++++++++++++++++++++++++++++ libc/sysdeps/linux/x86_64/ucontext_i.sym | 37 +++++++++ 7 files changed, 558 insertions(+) create mode 100644 libc/sysdeps/linux/x86_64/__start_context.S create mode 100644 libc/sysdeps/linux/x86_64/getcontext.S create mode 100644 libc/sysdeps/linux/x86_64/makecontext.c create mode 100644 libc/sysdeps/linux/x86_64/setcontext.S create mode 100644 libc/sysdeps/linux/x86_64/swapcontext.S create mode 100644 libc/sysdeps/linux/x86_64/ucontext_i.sym diff --git a/libc/sysdeps/linux/x86_64/Makefile.arch b/libc/sysdeps/linux/x86_64/Makefile.arch index 3243d86..bcf8096 100644 --- a/libc/sysdeps/linux/x86_64/Makefile.arch +++ b/libc/sysdeps/linux/x86_64/Makefile.arch @@ -10,6 +10,9 @@ CSRC := brk.c __syscall_error.c sigaction.c mmap.c SSRC := \ __longjmp.S setjmp.S syscall.S bsd-setjmp.S bsd-_setjmp.S +LIBC_ARCH_DIR := $(top_srcdir)/libc/sysdeps/linux/$(TARGET_ARCH) +LIBC_ARCH_OUT := $(top_builddir)/libc/sysdeps/linux/$(TARGET_ARCH) + ifneq ($(UCLIBC_HAS_THREADS_NATIVE),y) SSRC += vfork.S clone.S endif @@ -20,3 +23,39 @@ ifeq ($(UCLIBC_HAS_TLS),y) SSRC += sched_getcpu.S endif endif + +ifeq ($(UCLIBC_SUSV4_LEGACY),y) +CSRC += makecontext.c + +SSRC += setcontext.S getcontext.S swapcontext.S __start_context.S + +ASFLAGS-setcontext.S := -D_LIBC_REENTRANT +ASFLAGS-getcontext.S := -D_LIBC_REENTRANT +ASFLAGS-swapcontext.S := -D_LIBC_REENTRANT + +ifeq ($(UCLIBC_HAS_THREADS_NATIVE),y) +#Needed to use the correct SYSCALL_ERROR_HANDLER +ASFLAGS-setcontext.S += -DUSE___THREAD +ASFLAGS-getcontext.S += -DUSE___THREAD +ASFLAGS-swapcontext.S += -DUSE___THREAD +endif + +pregen-headers-$(UCLIBC_SUSV4_LEGACY) += $(LIBC_ARCH_OUT)/ucontext_i.h + +headers_clean-y += libc_arch_headers_clean + +CFLAGS-ucontext_i.c = -S + +$(LIBC_ARCH_OUT)/ucontext_i.c: $(LIBC_ARCH_DIR)/ucontext_i.sym + $(do_awk) $(top_srcdir)extra/scripts/gen-as-const.awk $< > $@ + +$(LIBC_ARCH_OUT)/ucontext_i.s: $(LIBC_ARCH_OUT)/ucontext_i.c + $(compile.c) + +$(LIBC_ARCH_OUT)/ucontext_i.h: $(LIBC_ARCH_OUT)/ucontext_i.s + $(do_sed) -n "s/^.*@@@name@@@\([^@]*\)@@@value@@@[^0-9Xxa-fA-F-]*\([0-9Xxa-fA-F-][0-9Xxa-fA-F-]*\).*@@@end@@@.*$\/#define \1 \2/p" $< > $@ + +libc_arch_headers_clean: + $(do_rm) $(addprefix $(LIBC_ARCH_OUT)/ucontext_i., c h s) +endif + diff --git a/libc/sysdeps/linux/x86_64/__start_context.S b/libc/sysdeps/linux/x86_64/__start_context.S new file mode 100644 index 0000000..9f2ee23 --- /dev/null +++ b/libc/sysdeps/linux/x86_64/__start_context.S @@ -0,0 +1,49 @@ +/* Copyright (C) 2002-2012 Free Software Foundation, Inc. + This file is part of the GNU C Library. + Contributed by Andreas Jaeger , 2002. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + . */ + +#include + +/* This is the helper code which gets called if a function which is + registered with 'makecontext' returns. In this case we have to + install the context listed in the uc_link element of the context + 'makecontext' manipulated at the time of the 'makecontext' call. + If the pointer is NULL the process must terminate. */ + + +ENTRY(__start_context) + /* This removes the parameters passed to the function given to + 'makecontext' from the stack. RBX contains the address + on the stack pointer for the next context. */ + movq %rbx, %rsp + + popq %rdi /* This is the next context. */ + cfi_adjust_cfa_offset(-8) + testq %rdi, %rdi + je 2f /* If it is zero exit. */ + + call JUMPTARGET(__setcontext) + /* If this returns (which can happen if the syscall fails) we'll + exit the program with the return error value (-1). */ + movq %rax,%rdi + +2: + call HIDDEN_JUMPTARGET(exit) + /* The 'exit' call should never return. In case it does cause + the process to terminate. */ + hlt +END(__start_context) diff --git a/libc/sysdeps/linux/x86_64/getcontext.S b/libc/sysdeps/linux/x86_64/getcontext.S new file mode 100644 index 0000000..dcebc4f --- /dev/null +++ b/libc/sysdeps/linux/x86_64/getcontext.S @@ -0,0 +1,88 @@ +/* Save current context. + Copyright (C) 2002-2012 Free Software Foundation, Inc. + This file is part of the GNU C Library. + Contributed by Andreas Jaeger , 2002. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + . */ + +#include + +#include "ucontext_i.h" + +/* int __getcontext (ucontext_t *ucp) + + Saves the machine context in UCP such that when it is activated, + it appears as if __getcontext() returned again. + + This implementation is intended to be used for *synchronous* context + switches only. Therefore, it does not have to save anything + other than the PRESERVED state. */ + + +ENTRY(__getcontext) + /* Save the preserved registers, the registers used for passing + args, and the return address. */ + movq %rbx, oRBX(%rdi) + movq %rbp, oRBP(%rdi) + movq %r12, oR12(%rdi) + movq %r13, oR13(%rdi) + movq %r14, oR14(%rdi) + movq %r15, oR15(%rdi) + + movq %rdi, oRDI(%rdi) + movq %rsi, oRSI(%rdi) + movq %rdx, oRDX(%rdi) + movq %rcx, oRCX(%rdi) + movq %r8, oR8(%rdi) + movq %r9, oR9(%rdi) + + movq (%rsp), %rcx + movq %rcx, oRIP(%rdi) + leaq 8(%rsp), %rcx /* Exclude the return address. */ + movq %rcx, oRSP(%rdi) + + /* We have separate floating-point register content memory on the + stack. We use the __fpregs_mem block in the context. Set the + links up correctly. */ + + leaq oFPREGSMEM(%rdi), %rcx + movq %rcx, oFPREGS(%rdi) + /* Save the floating-point environment. */ + fnstenv (%rcx) + fldenv (%rcx) + stmxcsr oMXCSR(%rdi) + + /* Save the current signal mask with + rt_sigprocmask (SIG_BLOCK, NULL, set,_NSIG/8). */ + leaq oSIGMASK(%rdi), %rdx + xorl %esi,%esi +#if SIG_BLOCK == 0 + xorl %edi, %edi +#else + movl $SIG_BLOCK, %edi +#endif + movl $_NSIG8,%r10d + movl $__NR_rt_sigprocmask, %eax + syscall + cmpq $-4095, %rax /* Check %rax for error. */ + jae SYSCALL_ERROR_LABEL /* Jump to error handler if error. */ + + /* All done, return 0 for success. */ + xorl %eax, %eax +L(pseudo_end): + ret +PSEUDO_END(__getcontext) + +weak_alias (__getcontext, getcontext) diff --git a/libc/sysdeps/linux/x86_64/makecontext.c b/libc/sysdeps/linux/x86_64/makecontext.c new file mode 100644 index 0000000..5473031 --- /dev/null +++ b/libc/sysdeps/linux/x86_64/makecontext.c @@ -0,0 +1,121 @@ +/* Create new context. + Copyright (C) 2002, 2004, 2005, 2008 Free Software Foundation, Inc. + This file is part of the GNU C Library. + Contributed by Andreas Jaeger , 2002. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + . */ + +#include +#include +#include +#include + +#include "ucontext_i.h" + +/* This implementation can handle any ARGC value but only + normal integer parameters. + makecontext sets up a stack and the registers for the + user context. The stack looks like this: + +-----------------------+ + | next context | + +-----------------------+ + | parameter 7-n | + +-----------------------+ + | trampoline address | + %rsp -> +-----------------------+ + + The registers are set up like this: + %rdi,%rsi,%rdx,%rcx,%r8,%r9: parameter 1 to 6 + %rbx : address of next context + %rsp : stack pointer. +*/ + +/* XXX: This implementation currently only handles integer arguments. + To handle long int and pointer arguments the va_arg arguments needs + to be changed to long and also the stdlib/tst-setcontext.c file needs + to be changed to pass long arguments to makecontext. */ + + +void +__makecontext (ucontext_t *ucp, void (*func) (void), int argc, ...) +{ + extern void __start_context (void); + greg_t *sp; + unsigned int idx_uc_link; + va_list ap; + int i; + + /* Generate room on stack for parameter if needed and uc_link. */ + sp = (greg_t *) ((uintptr_t) ucp->uc_stack.ss_sp + + ucp->uc_stack.ss_size); + sp -= (argc > 6 ? argc - 6 : 0) + 1; + /* Align stack and make space for trampoline address. */ + sp = (greg_t *) ((((uintptr_t) sp) & -16L) - 8); + + idx_uc_link = (argc > 6 ? argc - 6 : 0) + 1; + + /* Setup context ucp. */ + /* Address to jump to. */ + ucp->uc_mcontext.gregs[REG_RIP] = (uintptr_t) func; + /* Setup rbx.*/ + ucp->uc_mcontext.gregs[REG_RBX] = (uintptr_t) &sp[idx_uc_link]; + ucp->uc_mcontext.gregs[REG_RSP] = (uintptr_t) sp; + + /* Setup stack. */ + sp[0] = (uintptr_t) &__start_context; + sp[idx_uc_link] = (uintptr_t) ucp->uc_link; + + va_start (ap, argc); + /* Handle arguments. + + The standard says the parameters must all be int values. This is + an historic accident and would be done differently today. For + x86-64 all integer values are passed as 64-bit values and + therefore extending the API to copy 64-bit values instead of + 32-bit ints makes sense. It does not break existing + functionality and it does not violate the standard which says + that passing non-int values means undefined behavior. */ + for (i = 0; i < argc; ++i) + switch (i) + { + case 0: + ucp->uc_mcontext.gregs[REG_RDI] = va_arg (ap, greg_t); + break; + case 1: + ucp->uc_mcontext.gregs[REG_RSI] = va_arg (ap, greg_t); + break; + case 2: + ucp->uc_mcontext.gregs[REG_RDX] = va_arg (ap, greg_t); + break; + case 3: + ucp->uc_mcontext.gregs[REG_RCX] = va_arg (ap, greg_t); + break; + case 4: + ucp->uc_mcontext.gregs[REG_R8] = va_arg (ap, greg_t); + break; + case 5: + ucp->uc_mcontext.gregs[REG_R9] = va_arg (ap, greg_t); + break; + default: + /* Put value on stack. */ + sp[i - 5] = va_arg (ap, greg_t); + break; + } + va_end (ap); + +} + + +weak_alias (__makecontext, makecontext) diff --git a/libc/sysdeps/linux/x86_64/setcontext.S b/libc/sysdeps/linux/x86_64/setcontext.S new file mode 100644 index 0000000..561ab9f --- /dev/null +++ b/libc/sysdeps/linux/x86_64/setcontext.S @@ -0,0 +1,103 @@ +/* Install given context. + Copyright (C) 2002-2012 Free Software Foundation, Inc. + This file is part of the GNU C Library. + Contributed by Andreas Jaeger , 2002. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + . */ + +#include + +#include "ucontext_i.h" + + +/* int __setcontext (const ucontext_t *ucp) + + Restores the machine context in UCP and thereby resumes execution + in that context. + + This implementation is intended to be used for *synchronous* context + switches only. Therefore, it does not have to restore anything + other than the PRESERVED state. */ + +ENTRY(__setcontext) + /* Save argument since syscall will destroy it. */ + pushq %rdi + cfi_adjust_cfa_offset(8) + + /* Set the signal mask with + rt_sigprocmask (SIG_SETMASK, mask, NULL, _NSIG/8). */ + leaq oSIGMASK(%rdi), %rsi + xorl %edx, %edx + movl $SIG_SETMASK, %edi + movl $_NSIG8,%r10d + movl $__NR_rt_sigprocmask, %eax + syscall + popq %rdi /* Reload %rdi, adjust stack. */ + cfi_adjust_cfa_offset(-8) + cmpq $-4095, %rax /* Check %rax for error. */ + jae SYSCALL_ERROR_LABEL /* Jump to error handler if error. */ + + /* Restore the floating-point context. Not the registers, only the + rest. */ + movq oFPREGS(%rdi), %rcx + fldenv (%rcx) + ldmxcsr oMXCSR(%rdi) + + + /* Load the new stack pointer, the preserved registers and + registers used for passing args. */ + cfi_def_cfa(%rdi, 0) + cfi_offset(%rbx,oRBX) + cfi_offset(%rbp,oRBP) + cfi_offset(%r12,oR12) + cfi_offset(%r13,oR13) + cfi_offset(%r14,oR14) + cfi_offset(%r15,oR15) + cfi_offset(%rsp,oRSP) + cfi_offset(%rip,oRIP) + + movq oRSP(%rdi), %rsp + movq oRBX(%rdi), %rbx + movq oRBP(%rdi), %rbp + movq oR12(%rdi), %r12 + movq oR13(%rdi), %r13 + movq oR14(%rdi), %r14 + movq oR15(%rdi), %r15 + + /* The following ret should return to the address set with + getcontext. Therefore push the address on the stack. */ + movq oRIP(%rdi), %rcx + pushq %rcx + + movq oRSI(%rdi), %rsi + movq oRDX(%rdi), %rdx + movq oRCX(%rdi), %rcx + movq oR8(%rdi), %r8 + movq oR9(%rdi), %r9 + + /* Setup finally %rdi. */ + movq oRDI(%rdi), %rdi + + /* End FDE here, we fall into another context. */ + cfi_endproc + cfi_startproc + + /* Clear rax to indicate success. */ + xorl %eax, %eax +L(pseudo_end): + ret +PSEUDO_END(__setcontext) + +weak_alias (__setcontext, setcontext) diff --git a/libc/sysdeps/linux/x86_64/swapcontext.S b/libc/sysdeps/linux/x86_64/swapcontext.S new file mode 100644 index 0000000..6d2ebb8 --- /dev/null +++ b/libc/sysdeps/linux/x86_64/swapcontext.S @@ -0,0 +1,121 @@ +/* Save current context and install the given one. + Copyright (C) 2002-2012 Free Software Foundation, Inc. + This file is part of the GNU C Library. + Contributed by Andreas Jaeger , 2002. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + . */ + +#include + +#include "ucontext_i.h" + + +/* int __swapcontext (ucontext_t *oucp, const ucontext_t *ucp); + + Saves the machine context in oucp such that when it is activated, + it appears as if __swapcontextt() returned again, restores the + machine context in ucp and thereby resumes execution in that + context. + + This implementation is intended to be used for *synchronous* context + switches only. Therefore, it does not have to save anything + other than the PRESERVED state. */ + +ENTRY(__swapcontext) + /* Save the preserved registers, the registers used for passing args, + and the return address. */ + movq %rbx, oRBX(%rdi) + movq %rbp, oRBP(%rdi) + movq %r12, oR12(%rdi) + movq %r13, oR13(%rdi) + movq %r14, oR14(%rdi) + movq %r15, oR15(%rdi) + + movq %rdi, oRDI(%rdi) + movq %rsi, oRSI(%rdi) + movq %rdx, oRDX(%rdi) + movq %rcx, oRCX(%rdi) + movq %r8, oR8(%rdi) + movq %r9, oR9(%rdi) + + movq (%rsp), %rcx + movq %rcx, oRIP(%rdi) + leaq 8(%rsp), %rcx /* Exclude the return address. */ + movq %rcx, oRSP(%rdi) + + /* We have separate floating-point register content memory on the + stack. We use the __fpregs_mem block in the context. Set the + links up correctly. */ + leaq oFPREGSMEM(%rdi), %rcx + movq %rcx, oFPREGS(%rdi) + /* Save the floating-point environment. */ + fnstenv (%rcx) + stmxcsr oMXCSR(%rdi) + + + /* The syscall destroys some registers, save them. */ + movq %rsi, %r12 + + /* Save the current signal mask and install the new one with + rt_sigprocmask (SIG_BLOCK, newset, oldset,_NSIG/8). */ + leaq oSIGMASK(%rdi), %rdx + leaq oSIGMASK(%rsi), %rsi + movl $SIG_SETMASK, %edi + movl $_NSIG8,%r10d + movl $__NR_rt_sigprocmask, %eax + syscall + cmpq $-4095, %rax /* Check %rax for error. */ + jae SYSCALL_ERROR_LABEL /* Jump to error handler if error. */ + + /* Restore destroyed registers. */ + movq %r12, %rsi + + /* Restore the floating-point context. Not the registers, only the + rest. */ + movq oFPREGS(%rsi), %rcx + fldenv (%rcx) + ldmxcsr oMXCSR(%rsi) + + /* Load the new stack pointer and the preserved registers. */ + movq oRSP(%rsi), %rsp + movq oRBX(%rsi), %rbx + movq oRBP(%rsi), %rbp + movq oR12(%rsi), %r12 + movq oR13(%rsi), %r13 + movq oR14(%rsi), %r14 + movq oR15(%rsi), %r15 + + /* The following ret should return to the address set with + getcontext. Therefore push the address on the stack. */ + movq oRIP(%rsi), %rcx + pushq %rcx + + /* Setup registers used for passing args. */ + movq oRDI(%rsi), %rdi + movq oRDX(%rsi), %rdx + movq oRCX(%rsi), %rcx + movq oR8(%rsi), %r8 + movq oR9(%rsi), %r9 + + /* Setup finally %rsi. */ + movq oRSI(%rsi), %rsi + + /* Clear rax to indicate success. */ + xorl %eax, %eax +L(pseudo_end): + ret +PSEUDO_END(__swapcontext) + +weak_alias (__swapcontext, swapcontext) diff --git a/libc/sysdeps/linux/x86_64/ucontext_i.sym b/libc/sysdeps/linux/x86_64/ucontext_i.sym new file mode 100644 index 0000000..af3e0e5 --- /dev/null +++ b/libc/sysdeps/linux/x86_64/ucontext_i.sym @@ -0,0 +1,37 @@ +#include +#include +#include + +-- + +SIG_BLOCK +SIG_SETMASK + +_NSIG8 (_NSIG / 8) + +#define ucontext(member) offsetof (ucontext_t, member) +#define mcontext(member) ucontext (uc_mcontext.member) +#define mreg(reg) mcontext (gregs[REG_##reg]) + +oRBP mreg (RBP) +oRSP mreg (RSP) +oRBX mreg (RBX) +oR8 mreg (R8) +oR9 mreg (R9) +oR10 mreg (R10) +oR11 mreg (R11) +oR12 mreg (R12) +oR13 mreg (R13) +oR14 mreg (R14) +oR15 mreg (R15) +oRDI mreg (RDI) +oRSI mreg (RSI) +oRDX mreg (RDX) +oRAX mreg (RAX) +oRCX mreg (RCX) +oRIP mreg (RIP) +oEFL mreg (EFL) +oFPREGS mcontext (fpregs) +oSIGMASK ucontext (uc_sigmask) +oFPREGSMEM ucontext (__fpregs_mem) +oMXCSR ucontext (__fpregs_mem.mxcsr) -- 1.8.0