| Message ID | 20240217202535.1860803-1-flaviocruz@gmail.com |
|---|---|
| State | New |
| Headers | show |
| Series | Implement setcontext/getcontext/makecontext/swapcontext for Hurd x86_64 | expand |
Applied, thanks!! Flavio Cruz, le sam. 17 févr. 2024 15:25:35 -0500, a ecrit: > Tested with the tests provided by glibc plus some other toy examples. > --- > sysdeps/mach/hurd/x86_64/Makefile | 4 + > sysdeps/mach/hurd/x86_64/__start_context.S | 49 +++++++++ > sysdeps/mach/hurd/x86_64/getcontext.S | 68 ++++++++++++ > sysdeps/mach/hurd/x86_64/makecontext.c | 119 ++++++++++++++++++++ > sysdeps/mach/hurd/x86_64/setcontext.S | 96 +++++++++++++++++ > sysdeps/mach/hurd/x86_64/swapcontext.S | 120 +++++++++++++++++++++ > 6 files changed, 456 insertions(+) > create mode 100644 sysdeps/mach/hurd/x86_64/__start_context.S > create mode 100644 sysdeps/mach/hurd/x86_64/getcontext.S > create mode 100644 sysdeps/mach/hurd/x86_64/makecontext.c > create mode 100644 sysdeps/mach/hurd/x86_64/setcontext.S > create mode 100644 sysdeps/mach/hurd/x86_64/swapcontext.S > > diff --git a/sysdeps/mach/hurd/x86_64/Makefile b/sysdeps/mach/hurd/x86_64/Makefile > index 80cf2eb6..2b43f5d6 100644 > --- a/sysdeps/mach/hurd/x86_64/Makefile > +++ b/sysdeps/mach/hurd/x86_64/Makefile > @@ -3,3 +3,7 @@ ifeq ($(subdir),conform) > # (missing SA_NOCLDWAIT) > conformtest-xfail-conds += x86_64-gnu > endif > + > +ifeq ($(subdir),stdlib) > +sysdep_routines += __start_context > +endif > diff --git a/sysdeps/mach/hurd/x86_64/__start_context.S b/sysdeps/mach/hurd/x86_64/__start_context.S > new file mode 100644 > index 00000000..3cb4c6b5 > --- /dev/null > +++ b/sysdeps/mach/hurd/x86_64/__start_context.S > @@ -0,0 +1,49 @@ > +/* Copyright (C) 2024 Free Software Foundation, Inc. > + This file is part of the GNU C Library. > + > + 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 > + <https://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 > + > + /* Don't use pop here so that stack is aligned to 16 bytes. */ > + movq (%rsp), %rdi /* This is the next context. */ > + testq %rdi, %rdi > + je 2f /* If it is zero exit. */ > + > + call __setcontext > + /* If this returns (which can happen if __sigprocmask 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. */ > +L(hlt): > + hlt > +END(__start_context) > diff --git a/sysdeps/mach/hurd/x86_64/getcontext.S b/sysdeps/mach/hurd/x86_64/getcontext.S > new file mode 100644 > index 00000000..ef431be1 > --- /dev/null > +++ b/sysdeps/mach/hurd/x86_64/getcontext.S > @@ -0,0 +1,68 @@ > +/* Save current context. > + Copyright (C) 2024 Free Software Foundation, Inc. > + This file is part of the GNU C Library. > + > + 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 > + <https://www.gnu.org/licenses/>. */ > + > +#include <sysdep.h> > + > +#include "ucontext_i.h" > + > + > +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 > + * __sigprocmask(SIG_BLOCK, NULL, oSIGMASK(%rdi)); */ > + leaq oSIGMASK(%rdi), %rdx > + movq $0, %rsi > + movl $SIG_BLOCK, %edi > + call HIDDEN_JUMPTARGET (__sigprocmask) > + > + /* Propagate %rax (and errno, in case). */ > + ret > +PSEUDO_END(__getcontext) > + > +weak_alias (__getcontext, getcontext) > diff --git a/sysdeps/mach/hurd/x86_64/makecontext.c b/sysdeps/mach/hurd/x86_64/makecontext.c > new file mode 100644 > index 00000000..6990a777 > --- /dev/null > +++ b/sysdeps/mach/hurd/x86_64/makecontext.c > @@ -0,0 +1,119 @@ > +/* Create new context. > + Copyright (C) 2024 Free Software Foundation, Inc. > + This file is part of the GNU C Library. > + > + 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 > + <https://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) attribute_hidden; > + 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/sysdeps/mach/hurd/x86_64/setcontext.S b/sysdeps/mach/hurd/x86_64/setcontext.S > new file mode 100644 > index 00000000..99919ee2 > --- /dev/null > +++ b/sysdeps/mach/hurd/x86_64/setcontext.S > @@ -0,0 +1,96 @@ > +/* Install given context. > + Copyright (C) 2024 Free Software Foundation, Inc. > + This file is part of the GNU C Library. > + > + 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 > + <https://www.gnu.org/licenses/>. */ > + > +#include <sysdep.h> > + > +#include "ucontext_i.h" > + > + > +ENTRY(__setcontext) > + /* Save argument since call will destroy it. */ > + pushq %rdi > + cfi_adjust_cfa_offset(8) > + > + /* Set the signal mask with > + __sigprocmask (SIG_SETMASK, mask, NULL). */ > + xorl %edx, %edx > + leaq oSIGMASK(%rdi), %rsi > + movl $SIG_SETMASK, %edi > + call HIDDEN_JUMPTARGET (__sigprocmask) > + /* Pop the pointer into RDX. The choice is arbitrary, but > + leaving RDI and RSI available for use later can avoid > + shuffling values. */ > + popq %rdx > + > + test %rax, %rax > + jne L(pseudo_end) > + > + /* Restore the floating-point context. Not the registers, only the > + rest. */ > + movq oFPREGS(%rdx), %rcx > + fldenv (%rcx) > + ldmxcsr oMXCSR(%rdx) > + > + /* Load the new stack pointer, the preserved registers and > + registers used for passing args. */ > + cfi_def_cfa(%rdx, 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(%rdx), %rsp > + movq oRBX(%rdx), %rbx > + movq oRBP(%rdx), %rbp > + movq oR12(%rdx), %r12 > + movq oR13(%rdx), %r13 > + movq oR14(%rdx), %r14 > + movq oR15(%rdx), %r15 > + > + /* The following ret should return to the address set with > + getcontext. Therefore push the address on the stack. */ > + movq oRIP(%rdx), %rcx > + pushq %rcx > + > + movq oRSI(%rdx), %rsi > + movq oRDI(%rdx), %rdi > + movq oRCX(%rdx), %rcx > + movq oR8(%rdx), %r8 > + movq oR9(%rdx), %r9 > + > + /* Setup finally %rdx. */ > + movq oRDX(%rdx), %rdx > + > + /* End FDE here, we fall into another context. */ > + cfi_endproc > + cfi_startproc > + > + /* Clear rax to indicate success. */ > + xorl %eax, %eax > +L(pseudo_end): > + /* The following 'ret' will pop the address of the code and jump > + to it. */ > + ret > +PSEUDO_END(__setcontext) > +libc_hidden_def (__setcontext) > + > +weak_alias (__setcontext, setcontext) > diff --git a/sysdeps/mach/hurd/x86_64/swapcontext.S b/sysdeps/mach/hurd/x86_64/swapcontext.S > new file mode 100644 > index 00000000..79718a1f > --- /dev/null > +++ b/sysdeps/mach/hurd/x86_64/swapcontext.S > @@ -0,0 +1,120 @@ > +/* Save current context and install the given one. > + Copyright (C) 2024 Free Software Foundation, Inc. > + This file is part of the GNU C Library. > + > + 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 > + <https://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 function call destroys some registers, save ucp. */ > + movq %rsi, %r12 > + > + /* Save the current signal mask and install the new one with > + __sigprocmask (SIG_BLOCK, newset, oldset). */ > + leaq oSIGMASK(%rdi), %rdx > + leaq oSIGMASK(%rsi), %rsi > + movl $SIG_SETMASK, %edi > + call HIDDEN_JUMPTARGET (__sigprocmask) > + test %rax, %rax > + jne L(pseudo_end) > + > + /* Restore destroyed register into RDX. The choice is arbitrary, > + but leaving RDI and RSI available for use later can avoid > + shuffling values. */ > + movq %r12, %rdx > + > + /* Restore the floating-point context. Not the registers, only the > + rest. */ > + movq oFPREGS(%rdx), %rcx > + fldenv (%rcx) > + ldmxcsr oMXCSR(%rdx) > + > + /* Load the new stack pointer and the preserved registers. */ > + movq oRSP(%rdx), %rsp > + movq oRBX(%rdx), %rbx > + movq oRBP(%rdx), %rbp > + movq oR12(%rdx), %r12 > + movq oR13(%rdx), %r13 > + movq oR14(%rdx), %r14 > + movq oR15(%rdx), %r15 > + > + /* The following ret should return to the address set with > + getcontext. Therefore push the address on the stack. */ > + movq oRIP(%rdx), %rcx > + pushq %rcx > + > + /* Setup registers used for passing args. */ > + movq oRDI(%rdx), %rdi > + movq oRSI(%rdx), %rsi > + movq oRCX(%rdx), %rcx > + movq oR8(%rdx), %r8 > + movq oR9(%rdx), %r9 > + > + /* Setup finally %rdx. */ > + movq oRDX(%rdx), %rdx > + > + /* Clear rax to indicate success. */ > + xorl %eax, %eax > +L(pseudo_end): > + ret > +PSEUDO_END(__swapcontext) > + > +weak_alias (__swapcontext, swapcontext) > -- > 2.39.2 >
diff --git a/sysdeps/mach/hurd/x86_64/Makefile b/sysdeps/mach/hurd/x86_64/Makefile index 80cf2eb6..2b43f5d6 100644 --- a/sysdeps/mach/hurd/x86_64/Makefile +++ b/sysdeps/mach/hurd/x86_64/Makefile @@ -3,3 +3,7 @@ ifeq ($(subdir),conform) # (missing SA_NOCLDWAIT) conformtest-xfail-conds += x86_64-gnu endif + +ifeq ($(subdir),stdlib) +sysdep_routines += __start_context +endif diff --git a/sysdeps/mach/hurd/x86_64/__start_context.S b/sysdeps/mach/hurd/x86_64/__start_context.S new file mode 100644 index 00000000..3cb4c6b5 --- /dev/null +++ b/sysdeps/mach/hurd/x86_64/__start_context.S @@ -0,0 +1,49 @@ +/* Copyright (C) 2024 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + 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 + <https://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 + + /* Don't use pop here so that stack is aligned to 16 bytes. */ + movq (%rsp), %rdi /* This is the next context. */ + testq %rdi, %rdi + je 2f /* If it is zero exit. */ + + call __setcontext + /* If this returns (which can happen if __sigprocmask 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. */ +L(hlt): + hlt +END(__start_context) diff --git a/sysdeps/mach/hurd/x86_64/getcontext.S b/sysdeps/mach/hurd/x86_64/getcontext.S new file mode 100644 index 00000000..ef431be1 --- /dev/null +++ b/sysdeps/mach/hurd/x86_64/getcontext.S @@ -0,0 +1,68 @@ +/* Save current context. + Copyright (C) 2024 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + 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 + <https://www.gnu.org/licenses/>. */ + +#include <sysdep.h> + +#include "ucontext_i.h" + + +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 + * __sigprocmask(SIG_BLOCK, NULL, oSIGMASK(%rdi)); */ + leaq oSIGMASK(%rdi), %rdx + movq $0, %rsi + movl $SIG_BLOCK, %edi + call HIDDEN_JUMPTARGET (__sigprocmask) + + /* Propagate %rax (and errno, in case). */ + ret +PSEUDO_END(__getcontext) + +weak_alias (__getcontext, getcontext) diff --git a/sysdeps/mach/hurd/x86_64/makecontext.c b/sysdeps/mach/hurd/x86_64/makecontext.c new file mode 100644 index 00000000..6990a777 --- /dev/null +++ b/sysdeps/mach/hurd/x86_64/makecontext.c @@ -0,0 +1,119 @@ +/* Create new context. + Copyright (C) 2024 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + 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 + <https://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) attribute_hidden; + 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/sysdeps/mach/hurd/x86_64/setcontext.S b/sysdeps/mach/hurd/x86_64/setcontext.S new file mode 100644 index 00000000..99919ee2 --- /dev/null +++ b/sysdeps/mach/hurd/x86_64/setcontext.S @@ -0,0 +1,96 @@ +/* Install given context. + Copyright (C) 2024 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + 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 + <https://www.gnu.org/licenses/>. */ + +#include <sysdep.h> + +#include "ucontext_i.h" + + +ENTRY(__setcontext) + /* Save argument since call will destroy it. */ + pushq %rdi + cfi_adjust_cfa_offset(8) + + /* Set the signal mask with + __sigprocmask (SIG_SETMASK, mask, NULL). */ + xorl %edx, %edx + leaq oSIGMASK(%rdi), %rsi + movl $SIG_SETMASK, %edi + call HIDDEN_JUMPTARGET (__sigprocmask) + /* Pop the pointer into RDX. The choice is arbitrary, but + leaving RDI and RSI available for use later can avoid + shuffling values. */ + popq %rdx + + test %rax, %rax + jne L(pseudo_end) + + /* Restore the floating-point context. Not the registers, only the + rest. */ + movq oFPREGS(%rdx), %rcx + fldenv (%rcx) + ldmxcsr oMXCSR(%rdx) + + /* Load the new stack pointer, the preserved registers and + registers used for passing args. */ + cfi_def_cfa(%rdx, 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(%rdx), %rsp + movq oRBX(%rdx), %rbx + movq oRBP(%rdx), %rbp + movq oR12(%rdx), %r12 + movq oR13(%rdx), %r13 + movq oR14(%rdx), %r14 + movq oR15(%rdx), %r15 + + /* The following ret should return to the address set with + getcontext. Therefore push the address on the stack. */ + movq oRIP(%rdx), %rcx + pushq %rcx + + movq oRSI(%rdx), %rsi + movq oRDI(%rdx), %rdi + movq oRCX(%rdx), %rcx + movq oR8(%rdx), %r8 + movq oR9(%rdx), %r9 + + /* Setup finally %rdx. */ + movq oRDX(%rdx), %rdx + + /* End FDE here, we fall into another context. */ + cfi_endproc + cfi_startproc + + /* Clear rax to indicate success. */ + xorl %eax, %eax +L(pseudo_end): + /* The following 'ret' will pop the address of the code and jump + to it. */ + ret +PSEUDO_END(__setcontext) +libc_hidden_def (__setcontext) + +weak_alias (__setcontext, setcontext) diff --git a/sysdeps/mach/hurd/x86_64/swapcontext.S b/sysdeps/mach/hurd/x86_64/swapcontext.S new file mode 100644 index 00000000..79718a1f --- /dev/null +++ b/sysdeps/mach/hurd/x86_64/swapcontext.S @@ -0,0 +1,120 @@ +/* Save current context and install the given one. + Copyright (C) 2024 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + 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 + <https://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 function call destroys some registers, save ucp. */ + movq %rsi, %r12 + + /* Save the current signal mask and install the new one with + __sigprocmask (SIG_BLOCK, newset, oldset). */ + leaq oSIGMASK(%rdi), %rdx + leaq oSIGMASK(%rsi), %rsi + movl $SIG_SETMASK, %edi + call HIDDEN_JUMPTARGET (__sigprocmask) + test %rax, %rax + jne L(pseudo_end) + + /* Restore destroyed register into RDX. The choice is arbitrary, + but leaving RDI and RSI available for use later can avoid + shuffling values. */ + movq %r12, %rdx + + /* Restore the floating-point context. Not the registers, only the + rest. */ + movq oFPREGS(%rdx), %rcx + fldenv (%rcx) + ldmxcsr oMXCSR(%rdx) + + /* Load the new stack pointer and the preserved registers. */ + movq oRSP(%rdx), %rsp + movq oRBX(%rdx), %rbx + movq oRBP(%rdx), %rbp + movq oR12(%rdx), %r12 + movq oR13(%rdx), %r13 + movq oR14(%rdx), %r14 + movq oR15(%rdx), %r15 + + /* The following ret should return to the address set with + getcontext. Therefore push the address on the stack. */ + movq oRIP(%rdx), %rcx + pushq %rcx + + /* Setup registers used for passing args. */ + movq oRDI(%rdx), %rdi + movq oRSI(%rdx), %rsi + movq oRCX(%rdx), %rcx + movq oR8(%rdx), %r8 + movq oR9(%rdx), %r9 + + /* Setup finally %rdx. */ + movq oRDX(%rdx), %rdx + + /* Clear rax to indicate success. */ + xorl %eax, %eax +L(pseudo_end): + ret +PSEUDO_END(__swapcontext) + +weak_alias (__swapcontext, swapcontext)