This patch adds support for {get,set,swap,make}context to the x86_64
architecture. Files are imported from glibc.
Signed-off-by: Natanael Copa <nc...@alpinelinux.org>
Signed-off-by: Florian Fainelli <flor...@openwrt.org>
---
extra/Configs/Config.x86_64 | 1 +
libc/sysdeps/linux/x86_64/Makefile.arch | 6 ++
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 ++++++++
8 files changed, 526 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/extra/Configs/Config.x86_64 b/extra/Configs/Config.x86_64
index 1b28088..4c8c3a9 100644
--- a/extra/Configs/Config.x86_64
+++ b/extra/Configs/Config.x86_64
@@ -12,3 +12,4 @@ config FORCE_OPTIONS_FOR_ARCH
default y
select ARCH_LITTLE_ENDIAN
select ARCH_HAS_MMU
+ select ARCH_HAS_UCONTEXT
diff --git a/libc/sysdeps/linux/x86_64/Makefile.arch
b/libc/sysdeps/linux/x86_64/Makefile.arch
index 7491d92..455a6c1 100644
--- a/libc/sysdeps/linux/x86_64/Makefile.arch
+++ b/libc/sysdeps/linux/x86_64/Makefile.arch
@@ -20,3 +20,9 @@ ifeq ($(UCLIBC_HAS_TLS),y)
SSRC += sched_getcpu.S
endif
endif
+
+ifeq ($(UCLIBC_HAS_CONTEXT_FUNCS),y)
+CSRC += makecontext.c
+SSRC += setcontext.S getcontext.S swapcontext.S __start_context.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 <a...@suse.de>, 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
+ <http://www.gnu.org/licenses/>. */
+
+#include <sysdep.h>
+
+/* 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 <a...@suse.de>, 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
+ <http://www.gnu.org/licenses/>. */
+
+#include <sysdep.h>
+
+#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 <a...@suse.de>, 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
+ <http://www.gnu.org/licenses/>. */
+
+#include <sysdep.h>
+#include <stdarg.h>
+#include <stdint.h>
+#include <ucontext.h>
+
+#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 <a...@suse.de>, 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
+ <http://www.gnu.org/licenses/>. */
+
+#include <sysdep.h>
+
+#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 <a...@suse.de>, 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
+ <http://www.gnu.org/licenses/>. */
+
+#include <sysdep.h>
+
+#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 <stddef.h>
+#include <signal.h>
+#include <sys/ucontext.h>
+
+--
+
+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)
--
1.7.10.4
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