From a8dc90eaaa5e6474beac828558d969b1aafee4af Mon Sep 17 00:00:00 2001 From: Florian Fainelli Date: Wed, 9 Jan 2013 16:17:21 +0100 Subject: libc: add {get,set,swap,make}context user context manipulation functions Add the obsolescent SUSv3 family of user context manipulating functions for arm, i386, mips, x86_64. Signed-off-by: Timon ter Braak Signed-off-by: Florian Fainelli Signed-off-by: Bernhard Reutner-Fischer Signed-off-by: Natanael Copa Signed-off-by: Bernhard Reutner-Fischer --- libc/sysdeps/linux/i386/Makefile.arch | 4 ++ libc/sysdeps/linux/i386/getcontext.S | 84 ++++++++++++++++++++++ libc/sysdeps/linux/i386/makecontext.S | 123 +++++++++++++++++++++++++++++++++ libc/sysdeps/linux/i386/setcontext.S | 96 +++++++++++++++++++++++++ libc/sysdeps/linux/i386/swapcontext.S | 110 +++++++++++++++++++++++++++++ libc/sysdeps/linux/i386/ucontext_i.sym | 30 ++++++++ 6 files changed, 447 insertions(+) create mode 100644 libc/sysdeps/linux/i386/getcontext.S create mode 100644 libc/sysdeps/linux/i386/makecontext.S create mode 100644 libc/sysdeps/linux/i386/setcontext.S create mode 100644 libc/sysdeps/linux/i386/swapcontext.S create mode 100644 libc/sysdeps/linux/i386/ucontext_i.sym (limited to 'libc/sysdeps/linux/i386') diff --git a/libc/sysdeps/linux/i386/Makefile.arch b/libc/sysdeps/linux/i386/Makefile.arch index a3bf32f56..e7fd28eea 100644 --- a/libc/sysdeps/linux/i386/Makefile.arch +++ b/libc/sysdeps/linux/i386/Makefile.arch @@ -18,3 +18,7 @@ endif ifneq ($(UCLIBC_HAS_THREADS_NATIVE),y) SSRC += vfork.S clone.S endif + +ifeq ($(UCLIBC_HAS_CONTEXT_FUNCS),y) +SSRC += makecontext.S setcontext.S getcontext.S swapcontext.S +endif diff --git a/libc/sysdeps/linux/i386/getcontext.S b/libc/sysdeps/linux/i386/getcontext.S new file mode 100644 index 000000000..3221b597c --- /dev/null +++ b/libc/sysdeps/linux/i386/getcontext.S @@ -0,0 +1,84 @@ +/* Save current context. + Copyright (C) 2001-2012 Free Software Foundation, Inc. + This file is part of the GNU C Library. + Contributed by Ulrich Drepper , 2001. + + 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" + + +ENTRY(__getcontext) + /* Load address of the context data structure. */ + movl 4(%esp), %eax + + /* Return value of getcontext. EAX is the only register whose + value is not preserved. */ + movl $0, oEAX(%eax) + + /* Save the 32-bit register values and the return address. */ + movl %ecx, oECX(%eax) + movl %edx, oEDX(%eax) + movl %edi, oEDI(%eax) + movl %esi, oESI(%eax) + movl %ebp, oEBP(%eax) + movl (%esp), %ecx + movl %ecx, oEIP(%eax) + leal 4(%esp), %ecx /* Exclude the return address. */ + movl %ecx, oESP(%eax) + movl %ebx, oEBX(%eax) + + /* Save the FS segment register. We don't touch the GS register + since it is used for threads. */ + xorl %edx, %edx + movw %fs, %dx + movl %edx, oFS(%eax) + + /* 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. */ + leal oFPREGSMEM(%eax), %ecx + movl %ecx, oFPREGS(%eax) + /* Save the floating-point context. */ + fnstenv (%ecx) + /* And load it right back since the processor changes the mask. + Intel thought this opcode to be used in interrupt handlers which + would block all exceptions. */ + fldenv (%ecx) + + /* Save the current signal mask. */ + pushl %ebx + cfi_adjust_cfa_offset (4) + cfi_rel_offset (ebx, 0) + leal oSIGMASK(%eax), %edx + xorl %ecx, %ecx + movl $SIG_BLOCK, %ebx + movl $__NR_sigprocmask, %eax + ENTER_KERNEL + popl %ebx + cfi_adjust_cfa_offset (-4) + cfi_restore (ebx) + cmpl $-4095, %eax /* Check %eax 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/i386/makecontext.S b/libc/sysdeps/linux/i386/makecontext.S new file mode 100644 index 000000000..d12799d80 --- /dev/null +++ b/libc/sysdeps/linux/i386/makecontext.S @@ -0,0 +1,123 @@ +/* Create new context. + Copyright (C) 2001,2002,2005,2007,2008,2009 Free Software Foundation, Inc. + This file is part of the GNU C Library. + Contributed by Ulrich Drepper , 2001. + + 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" + + +ENTRY(__makecontext) + movl 4(%esp), %eax + + /* Load the address of the function we are supposed to run. */ + movl 8(%esp), %ecx + + /* Compute the address of the stack. The information comes from + to us_stack element. */ + movl oSS_SP(%eax), %edx + movl %ecx, oEIP(%eax) + addl oSS_SIZE(%eax), %edx + + /* Remember the number of parameters for the exit handler since + it has to remove them. We store the number in the EBX register + which the function we will call must preserve. */ + movl 12(%esp), %ecx + movl %ecx, oEBX(%eax) + + /* Make room on the new stack for the parameters. + Room for the arguments, return address (== L(exitcode)) and + oLINK pointer is needed. One of the pointer sizes is subtracted + after aligning the stack. */ + negl %ecx + leal -4(%edx,%ecx,4), %edx + negl %ecx + + /* Align the stack. */ + andl $0xfffffff0, %edx + subl $4, %edx + + /* Store the future stack pointer. */ + movl %edx, oESP(%eax) + + /* Put the next context on the new stack (from the uc_link + element). */ + movl oLINK(%eax), %eax + movl %eax, 4(%edx,%ecx,4) + + /* Copy all the parameters. */ + jecxz 2f +1: movl 12(%esp,%ecx,4), %eax + movl %eax, (%edx,%ecx,4) + decl %ecx + jnz 1b +2: + + /* If the function we call returns we must continue with the + context which is given in the uc_link element. To do this + set the return address for the function the user provides + to a little bit of helper code which does the magic (see + below). */ +#ifdef __PIC__ + call 1f + cfi_adjust_cfa_offset (4) +1: popl %ecx + cfi_adjust_cfa_offset (-4) + addl $L(exitcode)-1b, %ecx + movl %ecx, (%edx) +#else + movl $L(exitcode), (%edx) +#endif + /* 'makecontext' returns no value. */ +L(pseudo_end): + ret + + /* 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. */ + cfi_endproc +L(exitcode): + /* This removes the parameters passed to the function given to + 'makecontext' from the stack. EBX contains the number of + parameters (see above). */ + leal (%esp,%ebx,4), %esp + +#ifdef __PIC__ + call 1f +1: popl %ebx + addl $_GLOBAL_OFFSET_TABLE_+[.-1b], %ebx +#endif + cmpl $0, (%esp) /* Check the next context. */ + 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). */ + + movl %eax, (%esp) +2: call HIDDEN_JUMPTARGET(exit) + /* The 'exit' call should never return. In case it does cause + the process to terminate. */ + hlt + cfi_startproc +END(__makecontext) + +weak_alias (__makecontext, makecontext) diff --git a/libc/sysdeps/linux/i386/setcontext.S b/libc/sysdeps/linux/i386/setcontext.S new file mode 100644 index 000000000..ae953cc6b --- /dev/null +++ b/libc/sysdeps/linux/i386/setcontext.S @@ -0,0 +1,96 @@ +/* Install given context. + Copyright (C) 2001-2012 Free Software Foundation, Inc. + This file is part of the GNU C Library. + Contributed by Ulrich Drepper , 2001. + + 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" + + +ENTRY(__setcontext) + /* Load address of the context data structure. */ + movl 4(%esp), %eax + + /* Get the current signal mask. Note that we preserve EBX in case + the system call fails and we return from the function with an + error. */ + pushl %ebx + cfi_adjust_cfa_offset (4) + xorl %edx, %edx + leal oSIGMASK(%eax), %ecx + movl $SIG_SETMASK, %ebx + cfi_rel_offset (ebx, 0) + movl $__NR_sigprocmask, %eax + ENTER_KERNEL + popl %ebx + cfi_adjust_cfa_offset (-4) + cfi_restore (ebx) + cmpl $-4095, %eax /* Check %eax for error. */ + jae SYSCALL_ERROR_LABEL /* Jump to error handler if error. */ + + /* EAX was modified, reload it. */ + movl 4(%esp), %eax + + /* Restore the floating-point context. Not the registers, only the + rest. */ + movl oFPREGS(%eax), %ecx + fldenv (%ecx) + + /* Restore the FS segment register. We don't touch the GS register + since it is used for threads. */ + movl oFS(%eax), %ecx + movw %cx, %fs + + /* Fetch the address to return to. */ + movl oEIP(%eax), %ecx + + /* Load the new stack pointer. */ + cfi_def_cfa (eax, 0) + cfi_offset (edi, oEDI) + cfi_offset (esi, oESI) + cfi_offset (ebp, oEBP) + cfi_offset (ebx, oEBX) + cfi_offset (edx, oEDX) + cfi_offset (ecx, oECX) + movl oESP(%eax), %esp + + /* Push the return address on the new stack so we can return there. */ + pushl %ecx + + /* Load the values of all the 32-bit registers (except ESP). + Since we are loading from EAX, it must be last. */ + movl oEDI(%eax), %edi + movl oESI(%eax), %esi + movl oEBP(%eax), %ebp + movl oEBX(%eax), %ebx + movl oEDX(%eax), %edx + movl oECX(%eax), %ecx + movl oEAX(%eax), %eax + + /* End FDE here, we fall into another context. */ + cfi_endproc + cfi_startproc + + /* The following 'ret' will pop the address of the code and jump + to it. */ + +L(pseudo_end): + ret +PSEUDO_END(__setcontext) + +weak_alias (__setcontext, setcontext) diff --git a/libc/sysdeps/linux/i386/swapcontext.S b/libc/sysdeps/linux/i386/swapcontext.S new file mode 100644 index 000000000..ee5d0e4d5 --- /dev/null +++ b/libc/sysdeps/linux/i386/swapcontext.S @@ -0,0 +1,110 @@ +/* Save current context and install the given one. + Copyright (C) 2001-2012 Free Software Foundation, Inc. + This file is part of the GNU C Library. + Contributed by Ulrich Drepper , 2001. + + 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" + + +ENTRY(__swapcontext) + /* Load address of the context data structure we save in. */ + movl 4(%esp), %eax + + /* Return value of swapcontext. EAX is the only register whose + value is not preserved. */ + movl $0, oEAX(%eax) + + /* Save the 32-bit register values and the return address. */ + movl %ecx, oECX(%eax) + movl %edx, oEDX(%eax) + movl %edi, oEDI(%eax) + movl %esi, oESI(%eax) + movl %ebp, oEBP(%eax) + movl (%esp), %ecx + movl %ecx, oEIP(%eax) + leal 4(%esp), %ecx + movl %ecx, oESP(%eax) + movl %ebx, oEBX(%eax) + + /* Save the FS segment register. */ + xorl %edx, %edx + movw %fs, %dx + movl %edx, oFS(%eax) + + /* 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. */ + leal oFPREGSMEM(%eax), %ecx + movl %ecx, oFPREGS(%eax) + /* Save the floating-point context. */ + fnstenv (%ecx) + + /* Load address of the context data structure we have to load. */ + movl 8(%esp), %ecx + + /* Save the current signal mask and install the new one. */ + pushl %ebx + leal oSIGMASK(%eax), %edx + leal oSIGMASK(%ecx), %ecx + movl $SIG_SETMASK, %ebx + movl $__NR_sigprocmask, %eax + ENTER_KERNEL + popl %ebx + cmpl $-4095, %eax /* Check %eax for error. */ + jae SYSCALL_ERROR_LABEL /* Jump to error handler if error. */ + + /* EAX was modified, reload it. */ + movl 8(%esp), %eax + + /* Restore the floating-point context. Not the registers, only the + rest. */ + movl oFPREGS(%eax), %ecx + fldenv (%ecx) + + /* Restore the FS segment register. We don't touch the GS register + since it is used for threads. */ + movl oFS(%eax), %edx + movw %dx, %fs + + /* Fetch the address to return to. */ + movl oEIP(%eax), %ecx + + /* Load the new stack pointer. */ + movl oESP(%eax), %esp + + /* Push the return address on the new stack so we can return there. */ + pushl %ecx + + /* Load the values of all the 32-bit registers (except ESP). + Since we are loading from EAX, it must be last. */ + movl oEDI(%eax), %edi + movl oESI(%eax), %esi + movl oEBP(%eax), %ebp + movl oEBX(%eax), %ebx + movl oEDX(%eax), %edx + movl oECX(%eax), %ecx + movl oEAX(%eax), %eax + + /* The following 'ret' will pop the address of the code and jump + to it. */ +L(pseudo_end): + ret +PSEUDO_END(__swapcontext) + +weak_alias (__swapcontext, swapcontext) diff --git a/libc/sysdeps/linux/i386/ucontext_i.sym b/libc/sysdeps/linux/i386/ucontext_i.sym new file mode 100644 index 000000000..b11a5509c --- /dev/null +++ b/libc/sysdeps/linux/i386/ucontext_i.sym @@ -0,0 +1,30 @@ +#include +#include +#include + +-- + +SIG_BLOCK +SIG_SETMASK + +#define ucontext(member) offsetof (ucontext_t, member) +#define mcontext(member) ucontext (uc_mcontext.member) +#define mreg(reg) mcontext (gregs[REG_##reg]) + +oLINK ucontext (uc_link) +oSS_SP ucontext (uc_stack.ss_sp) +oSS_SIZE ucontext (uc_stack.ss_size) +oGS mreg (GS) +oFS mreg (FS) +oEDI mreg (EDI) +oESI mreg (ESI) +oEBP mreg (EBP) +oESP mreg (ESP) +oEBX mreg (EBX) +oEDX mreg (EDX) +oECX mreg (ECX) +oEAX mreg (EAX) +oEIP mreg (EIP) +oFPREGS mcontext (fpregs) +oSIGMASK ucontext (uc_sigmask) +oFPREGSMEM ucontext (__fpregs_mem) -- cgit v1.2.3