| /** |
| * The fiber module provides lightweight threads aka fibers. |
| * |
| * Copyright: Copyright Sean Kelly 2005 - 2012. |
| * License: Distributed under the |
| * $(LINK2 http://www.boost.org/LICENSE_1_0.txt, Boost Software License 1.0). |
| * (See accompanying file LICENSE) |
| * Authors: Sean Kelly, Walter Bright, Alex Rønne Petersen, Martin Nowak |
| * Source: $(DRUNTIMESRC core/thread/fiber/package.d) |
| */ |
| |
| /* NOTE: This file has been patched from the original DMD distribution to |
| * work with the GDC compiler. |
| */ |
| module core.thread.fiber; |
| |
| import core.thread.context; |
| import core.thread.fiber.base : fiber_entryPoint, FiberBase; |
| import core.thread.threadbase; |
| import core.thread.threadgroup; |
| import core.thread.types; |
| |
| import core.memory : pageSize; |
| |
| /////////////////////////////////////////////////////////////////////////////// |
| // Fiber Platform Detection |
| /////////////////////////////////////////////////////////////////////////////// |
| |
| version (GNU) |
| { |
| import gcc.builtins; |
| version (GNU_StackGrowsDown) |
| version = StackGrowsDown; |
| } |
| else |
| { |
| // this should be true for most architectures |
| version = StackGrowsDown; |
| } |
| |
| version (Windows) |
| { |
| import core.stdc.stdlib : free, malloc; |
| import core.sys.windows.winbase; |
| import core.sys.windows.winnt; |
| } |
| |
| package |
| { |
| version (D_InlineAsm_X86) |
| { |
| version (Windows) |
| version = AsmX86_Windows; |
| else version (Posix) |
| version = AsmX86_Posix; |
| |
| version = AlignFiberStackTo16Byte; |
| } |
| else version (D_InlineAsm_X86_64) |
| { |
| version (Windows) |
| { |
| version = AsmX86_64_Windows; |
| version = AlignFiberStackTo16Byte; |
| } |
| else version (Posix) |
| { |
| version = AsmX86_64_Posix; |
| version = AlignFiberStackTo16Byte; |
| } |
| } |
| else version (X86) |
| { |
| version = AlignFiberStackTo16Byte; |
| |
| version (GNU_CET) |
| { |
| // fiber_switchContext does not support shadow stack from |
| // Intel CET. So use ucontext implementation. |
| } |
| else |
| { |
| version = AsmExternal; |
| |
| version (MinGW) |
| version = GNU_AsmX86_Windows; |
| else version (OSX) |
| version = AsmX86_Posix; |
| else version (Posix) |
| version = AsmX86_Posix; |
| } |
| } |
| else version (X86_64) |
| { |
| version = AlignFiberStackTo16Byte; |
| |
| version (GNU_CET) |
| { |
| // fiber_switchContext does not support shadow stack from |
| // Intel CET. So use ucontext implementation. |
| } |
| else version (D_X32) |
| { |
| // let X32 be handled by ucontext swapcontext |
| } |
| else |
| { |
| version = AsmExternal; |
| |
| version (MinGW) |
| version = GNU_AsmX86_64_Windows; |
| else version (OSX) |
| version = AsmX86_64_Posix; |
| else version (Posix) |
| version = AsmX86_64_Posix; |
| } |
| } |
| else version (PPC) |
| { |
| version (OSX) |
| { |
| version = AsmPPC_Darwin; |
| version = AsmExternal; |
| version = AlignFiberStackTo16Byte; |
| } |
| else version (Posix) |
| { |
| version = AsmPPC_Posix; |
| version = AsmExternal; |
| } |
| } |
| else version (PPC64) |
| { |
| version (OSX) |
| { |
| version = AsmPPC_Darwin; |
| version = AsmExternal; |
| version = AlignFiberStackTo16Byte; |
| } |
| else version (Posix) |
| { |
| version = AlignFiberStackTo16Byte; |
| } |
| } |
| else version (MIPS_O32) |
| { |
| version (Posix) |
| { |
| version = AsmMIPS_O32_Posix; |
| version = AsmExternal; |
| } |
| } |
| else version (MIPS_N64) |
| { |
| version (Posix) |
| { |
| version = AsmMIPS_N64_Posix; |
| version = AsmExternal; |
| } |
| } |
| else version (AArch64) |
| { |
| version (Posix) |
| { |
| version = AsmAArch64_Posix; |
| version = AsmExternal; |
| version = AlignFiberStackTo16Byte; |
| } |
| } |
| else version (ARM) |
| { |
| version (Posix) |
| { |
| version = AsmARM_Posix; |
| version = AsmExternal; |
| } |
| } |
| else version (SPARC) |
| { |
| // NOTE: The SPARC ABI specifies only doubleword alignment. |
| version = AlignFiberStackTo16Byte; |
| } |
| else version (SPARC64) |
| { |
| version = AlignFiberStackTo16Byte; |
| } |
| else version (LoongArch64) |
| { |
| version (Posix) |
| { |
| version = AsmLoongArch64_Posix; |
| version = AsmExternal; |
| version = AlignFiberStackTo16Byte; |
| } |
| } |
| |
| version (Posix) |
| { |
| version (AsmX86_Windows) {} else |
| version (AsmX86_Posix) {} else |
| version (AsmX86_64_Windows) {} else |
| version (AsmX86_64_Posix) {} else |
| version (AsmExternal) {} else |
| { |
| // NOTE: The ucontext implementation requires architecture specific |
| // data definitions to operate so testing for it must be done |
| // by checking for the existence of ucontext_t rather than by |
| // a version identifier. Please note that this is considered |
| // an obsolescent feature according to the POSIX spec, so a |
| // custom solution is still preferred. |
| import core.sys.posix.ucontext : getcontext, makecontext, MINSIGSTKSZ, swapcontext, ucontext_t; |
| } |
| } |
| } |
| |
| /////////////////////////////////////////////////////////////////////////////// |
| // Fiber Entry Point and Context Switch |
| /////////////////////////////////////////////////////////////////////////////// |
| |
| package |
| { |
| import core.atomic : atomicStore, cas, MemoryOrder; |
| import core.exception : onOutOfMemoryError; |
| import core.stdc.stdlib : abort; |
| |
| // Look above the definition of 'class Fiber' for some information about the implementation of this routine |
| version (AsmExternal) |
| { |
| extern (C) void fiber_switchContext( void** oldp, void* newp ) nothrow @nogc; |
| version (AArch64) |
| extern (C) void fiber_trampoline() nothrow; |
| } |
| else |
| extern (C) void fiber_switchContext( void** oldp, void* newp ) nothrow @nogc |
| { |
| // NOTE: The data pushed and popped in this routine must match the |
| // default stack created by Fiber.initStack or the initial |
| // switch into a new context will fail. |
| |
| version (AsmX86_Windows) |
| { |
| asm pure nothrow @nogc |
| { |
| naked; |
| |
| // save current stack state |
| push EBP; |
| mov EBP, ESP; |
| push EDI; |
| push ESI; |
| push EBX; |
| push dword ptr FS:[0]; |
| push dword ptr FS:[4]; |
| push dword ptr FS:[8]; |
| push EAX; |
| |
| // store oldp again with more accurate address |
| mov EAX, dword ptr 8[EBP]; |
| mov [EAX], ESP; |
| // load newp to begin context switch |
| mov ESP, dword ptr 12[EBP]; |
| |
| // load saved state from new stack |
| pop EAX; |
| pop dword ptr FS:[8]; |
| pop dword ptr FS:[4]; |
| pop dword ptr FS:[0]; |
| pop EBX; |
| pop ESI; |
| pop EDI; |
| pop EBP; |
| |
| // 'return' to complete switch |
| pop ECX; |
| jmp ECX; |
| } |
| } |
| else version (AsmX86_64_Windows) |
| { |
| asm pure nothrow @nogc |
| { |
| naked; |
| |
| // save current stack state |
| // NOTE: When changing the layout of registers on the stack, |
| // make sure that the XMM registers are still aligned. |
| // On function entry, the stack is guaranteed to not |
| // be aligned to 16 bytes because of the return address |
| // on the stack. |
| push RBP; |
| mov RBP, RSP; |
| push R12; |
| push R13; |
| push R14; |
| push R15; |
| push RDI; |
| push RSI; |
| // 7 registers = 56 bytes; stack is now aligned to 16 bytes |
| sub RSP, 160; |
| movdqa [RSP + 144], XMM6; |
| movdqa [RSP + 128], XMM7; |
| movdqa [RSP + 112], XMM8; |
| movdqa [RSP + 96], XMM9; |
| movdqa [RSP + 80], XMM10; |
| movdqa [RSP + 64], XMM11; |
| movdqa [RSP + 48], XMM12; |
| movdqa [RSP + 32], XMM13; |
| movdqa [RSP + 16], XMM14; |
| movdqa [RSP], XMM15; |
| push RBX; |
| xor RAX,RAX; |
| push qword ptr GS:[RAX]; |
| push qword ptr GS:8[RAX]; |
| push qword ptr GS:16[RAX]; |
| |
| // store oldp |
| mov [RCX], RSP; |
| // load newp to begin context switch |
| mov RSP, RDX; |
| |
| // load saved state from new stack |
| pop qword ptr GS:16[RAX]; |
| pop qword ptr GS:8[RAX]; |
| pop qword ptr GS:[RAX]; |
| pop RBX; |
| movdqa XMM15, [RSP]; |
| movdqa XMM14, [RSP + 16]; |
| movdqa XMM13, [RSP + 32]; |
| movdqa XMM12, [RSP + 48]; |
| movdqa XMM11, [RSP + 64]; |
| movdqa XMM10, [RSP + 80]; |
| movdqa XMM9, [RSP + 96]; |
| movdqa XMM8, [RSP + 112]; |
| movdqa XMM7, [RSP + 128]; |
| movdqa XMM6, [RSP + 144]; |
| add RSP, 160; |
| pop RSI; |
| pop RDI; |
| pop R15; |
| pop R14; |
| pop R13; |
| pop R12; |
| pop RBP; |
| |
| // 'return' to complete switch |
| pop RCX; |
| jmp RCX; |
| } |
| } |
| else version (AsmX86_Posix) |
| { |
| asm pure nothrow @nogc |
| { |
| naked; |
| |
| // save current stack state |
| push EBP; |
| mov EBP, ESP; |
| push EDI; |
| push ESI; |
| push EBX; |
| push EAX; |
| |
| // store oldp again with more accurate address |
| mov EAX, dword ptr 8[EBP]; |
| mov [EAX], ESP; |
| // load newp to begin context switch |
| mov ESP, dword ptr 12[EBP]; |
| |
| // load saved state from new stack |
| pop EAX; |
| pop EBX; |
| pop ESI; |
| pop EDI; |
| pop EBP; |
| |
| // 'return' to complete switch |
| pop ECX; |
| jmp ECX; |
| } |
| } |
| else version (AsmX86_64_Posix) |
| { |
| asm pure nothrow @nogc |
| { |
| naked; |
| |
| // save current stack state |
| push RBP; |
| mov RBP, RSP; |
| push RBX; |
| push R12; |
| push R13; |
| push R14; |
| push R15; |
| |
| // store oldp |
| mov [RDI], RSP; |
| // load newp to begin context switch |
| mov RSP, RSI; |
| |
| // load saved state from new stack |
| pop R15; |
| pop R14; |
| pop R13; |
| pop R12; |
| pop RBX; |
| pop RBP; |
| |
| // 'return' to complete switch |
| pop RCX; |
| jmp RCX; |
| } |
| } |
| else static if ( __traits( compiles, ucontext_t ) ) |
| { |
| Fiber cfib = Fiber.getThis(); |
| void* ucur = cfib.m_ucur; |
| |
| *oldp = &ucur; |
| swapcontext( **(cast(ucontext_t***) oldp), |
| *(cast(ucontext_t**) newp) ); |
| } |
| else |
| static assert(0, "Not implemented"); |
| } |
| } |
| |
| |
| /////////////////////////////////////////////////////////////////////////////// |
| // Fiber |
| /////////////////////////////////////////////////////////////////////////////// |
| /* |
| * Documentation of Fiber internals: |
| * |
| * The main routines to implement when porting Fibers to new architectures are |
| * fiber_switchContext and initStack. Some version constants have to be defined |
| * for the new platform as well, search for "Fiber Platform Detection and Memory Allocation". |
| * |
| * Fibers are based on a concept called 'Context'. A Context describes the execution |
| * state of a Fiber or main thread which is fully described by the stack, some |
| * registers and a return address at which the Fiber/Thread should continue executing. |
| * Please note that not only each Fiber has a Context, but each thread also has got a |
| * Context which describes the threads stack and state. If you call Fiber fib; fib.call |
| * the first time in a thread you switch from Threads Context into the Fibers Context. |
| * If you call fib.yield in that Fiber you switch out of the Fibers context and back |
| * into the Thread Context. (However, this is not always the case. You can call a Fiber |
| * from within another Fiber, then you switch Contexts between the Fibers and the Thread |
| * Context is not involved) |
| * |
| * In all current implementations the registers and the return address are actually |
| * saved on a Contexts stack. |
| * |
| * The fiber_switchContext routine has got two parameters: |
| * void** a: This is the _location_ where we have to store the current stack pointer, |
| * the stack pointer of the currently executing Context (Fiber or Thread). |
| * void* b: This is the pointer to the stack of the Context which we want to switch into. |
| * Note that we get the same pointer here as the one we stored into the void** a |
| * in a previous call to fiber_switchContext. |
| * |
| * In the simplest case, a fiber_switchContext rountine looks like this: |
| * fiber_switchContext: |
| * push {return Address} |
| * push {registers} |
| * copy {stack pointer} into {location pointed to by a} |
| * //We have now switch to the stack of a different Context! |
| * copy {b} into {stack pointer} |
| * pop {registers} |
| * pop {return Address} |
| * jump to {return Address} |
| * |
| * The GC uses the value returned in parameter a to scan the Fibers stack. It scans from |
| * the stack base to that value. As the GC dislikes false pointers we can actually optimize |
| * this a little: By storing registers which can not contain references to memory managed |
| * by the GC outside of the region marked by the stack base pointer and the stack pointer |
| * saved in fiber_switchContext we can prevent the GC from scanning them. |
| * Such registers are usually floating point registers and the return address. In order to |
| * implement this, we return a modified stack pointer from fiber_switchContext. However, |
| * we have to remember that when we restore the registers from the stack! |
| * |
| * --------------------------- <= Stack Base |
| * | Frame | <= Many other stack frames |
| * | Frame | |
| * |-------------------------| <= The last stack frame. This one is created by fiber_switchContext |
| * | registers with pointers | |
| * | | <= Stack pointer. GC stops scanning here |
| * | return address | |
| * |floating point registers | |
| * --------------------------- <= Real Stack End |
| * |
| * fiber_switchContext: |
| * push {registers with pointers} |
| * copy {stack pointer} into {location pointed to by a} |
| * push {return Address} |
| * push {Floating point registers} |
| * //We have now switch to the stack of a different Context! |
| * copy {b} into {stack pointer} |
| * //We now have to adjust the stack pointer to point to 'Real Stack End' so we can pop |
| * //the FP registers |
| * //+ or - depends on if your stack grows downwards or upwards |
| * {stack pointer} = {stack pointer} +- ({FPRegisters}.sizeof + {return address}.sizeof} |
| * pop {Floating point registers} |
| * pop {return Address} |
| * pop {registers with pointers} |
| * jump to {return Address} |
| * |
| * So the question now is which registers need to be saved? This depends on the specific |
| * architecture ABI of course, but here are some general guidelines: |
| * - If a register is callee-save (if the callee modifies the register it must saved and |
| * restored by the callee) it needs to be saved/restored in switchContext |
| * - If a register is caller-save it needn't be saved/restored. (Calling fiber_switchContext |
| * is a function call and the compiler therefore already must save these registers before |
| * calling fiber_switchContext) |
| * - Argument registers used for passing parameters to functions needn't be saved/restored |
| * - The return register needn't be saved/restored (fiber_switchContext hasn't got a return type) |
| * - All scratch registers needn't be saved/restored |
| * - The link register usually needn't be saved/restored (but sometimes it must be cleared - |
| * see below for details) |
| * - The frame pointer register - if it exists - is usually callee-save |
| * - All current implementations do not save control registers |
| * |
| * What happens on the first switch into a Fiber? We never saved a state for this fiber before, |
| * but the initial state is prepared in the initStack routine. (This routine will also be called |
| * when a Fiber is being resetted). initStack must produce exactly the same stack layout as the |
| * part of fiber_switchContext which saves the registers. Pay special attention to set the stack |
| * pointer correctly if you use the GC optimization mentioned before. the return Address saved in |
| * initStack must be the address of fiber_entrypoint. |
| * |
| * There's now a small but important difference between the first context switch into a fiber and |
| * further context switches. On the first switch, Fiber.call is used and the returnAddress in |
| * fiber_switchContext will point to fiber_entrypoint. The important thing here is that this jump |
| * is a _function call_, we call fiber_entrypoint by jumping before it's function prologue. On later |
| * calls, the user used yield() in a function, and therefore the return address points into a user |
| * function, after the yield call. So here the jump in fiber_switchContext is a _function return_, |
| * not a function call! |
| * |
| * The most important result of this is that on entering a function, i.e. fiber_entrypoint, we |
| * would have to provide a return address / set the link register once fiber_entrypoint |
| * returns. Now fiber_entrypoint does never return and therefore the actual value of the return |
| * address / link register is never read/used and therefore doesn't matter. When fiber_switchContext |
| * performs a _function return_ the value in the link register doesn't matter either. |
| * However, the link register will still be saved to the stack in fiber_entrypoint and some |
| * exception handling / stack unwinding code might read it from this stack location and crash. |
| * The exact solution depends on your architecture, but see the ARM implementation for a way |
| * to deal with this issue. |
| * |
| * The ARM implementation is meant to be used as a kind of documented example implementation. |
| * Look there for a concrete example. |
| * |
| * FIXME: fiber_entrypoint might benefit from a @noreturn attribute, but D doesn't have one. |
| */ |
| |
| /** |
| * This class provides a cooperative concurrency mechanism integrated with the |
| * threading and garbage collection functionality. Calling a fiber may be |
| * considered a blocking operation that returns when the fiber yields (via |
| * Fiber.yield()). Execution occurs within the context of the calling thread |
| * so synchronization is not necessary to guarantee memory visibility so long |
| * as the same thread calls the fiber each time. Please note that there is no |
| * requirement that a fiber be bound to one specific thread. Rather, fibers |
| * may be freely passed between threads so long as they are not currently |
| * executing. Like threads, a new fiber thread may be created using either |
| * derivation or composition, as in the following example. |
| * |
| * Warning: |
| * Status registers are not saved by the current implementations. This means |
| * floating point exception status bits (overflow, divide by 0), rounding mode |
| * and similar stuff is set per-thread, not per Fiber! |
| * |
| * Warning: |
| * On ARM FPU registers are not saved if druntime was compiled as ARM_SoftFloat. |
| * If such a build is used on a ARM_SoftFP system which actually has got a FPU |
| * and other libraries are using the FPU registers (other code is compiled |
| * as ARM_SoftFP) this can cause problems. Druntime must be compiled as |
| * ARM_SoftFP in this case. |
| * |
| * Authors: Based on a design by Mikola Lysenko. |
| */ |
| class Fiber : FiberBase |
| { |
| /////////////////////////////////////////////////////////////////////////// |
| // Initialization |
| /////////////////////////////////////////////////////////////////////////// |
| |
| version (Windows) |
| // exception handling walks the stack, invoking DbgHelp.dll which |
| // needs up to 16k of stack space depending on the version of DbgHelp.dll, |
| // the existence of debug symbols and other conditions. Avoid causing |
| // stack overflows by defaulting to a larger stack size |
| enum defaultStackPages = 8; |
| else version (OSX) |
| { |
| version (X86_64) |
| // libunwind on macOS 11 now requires more stack space than 16k, so |
| // default to a larger stack size. This is only applied to X86 as |
| // the pageSize is still 4k, however on AArch64 it is 16k. |
| enum defaultStackPages = 8; |
| else |
| enum defaultStackPages = 4; |
| } |
| else |
| enum defaultStackPages = 4; |
| |
| /** |
| * Initializes a fiber object which is associated with a static |
| * D function. |
| * |
| * Params: |
| * fn = The fiber function. |
| * sz = The stack size for this fiber. |
| * guardPageSize = size of the guard page to trap fiber's stack |
| * overflows. Beware that using this will increase |
| * the number of mmaped regions on platforms using mmap |
| * so an OS-imposed limit may be hit. |
| * |
| * In: |
| * fn must not be null. |
| */ |
| this( void function() fn, size_t sz = pageSize * defaultStackPages, |
| size_t guardPageSize = pageSize ) nothrow |
| { |
| super( fn, sz, guardPageSize ); |
| } |
| |
| |
| /** |
| * Initializes a fiber object which is associated with a dynamic |
| * D function. |
| * |
| * Params: |
| * dg = The fiber function. |
| * sz = The stack size for this fiber. |
| * guardPageSize = size of the guard page to trap fiber's stack |
| * overflows. Beware that using this will increase |
| * the number of mmaped regions on platforms using mmap |
| * so an OS-imposed limit may be hit. |
| * |
| * In: |
| * dg must not be null. |
| */ |
| this( void delegate() dg, size_t sz = pageSize * defaultStackPages, |
| size_t guardPageSize = pageSize ) nothrow |
| { |
| super( dg, sz, guardPageSize ); |
| } |
| |
| |
| /////////////////////////////////////////////////////////////////////////// |
| // Fiber Accessors |
| /////////////////////////////////////////////////////////////////////////// |
| |
| |
| /** |
| * Provides a reference to the calling fiber or null if no fiber is |
| * currently active. |
| * |
| * Returns: |
| * The fiber object representing the calling fiber or null if no fiber |
| * is currently active within this thread. The result of deleting this object is undefined. |
| */ |
| static Fiber getThis() @safe nothrow @nogc |
| { |
| return cast(Fiber) FiberBase.getThis(); |
| } |
| |
| |
| /////////////////////////////////////////////////////////////////////////// |
| // Static Initialization |
| /////////////////////////////////////////////////////////////////////////// |
| |
| |
| version (Posix) |
| { |
| static this() |
| { |
| static if ( __traits( compiles, ucontext_t ) ) |
| { |
| int status = getcontext( &sm_utxt ); |
| assert( status == 0 ); |
| } |
| } |
| } |
| |
| protected: |
| /////////////////////////////////////////////////////////////////////////// |
| // Stack Management |
| /////////////////////////////////////////////////////////////////////////// |
| |
| |
| // |
| // Allocate a new stack for this fiber. |
| // |
| final override void allocStack( size_t sz, size_t guardPageSize ) nothrow |
| in |
| { |
| assert( !m_pmem && !m_ctxt ); |
| } |
| do |
| { |
| // adjust alloc size to a multiple of pageSize |
| sz += pageSize - 1; |
| sz -= sz % pageSize; |
| |
| // NOTE: This instance of Thread.Context is dynamic so Fiber objects |
| // can be collected by the GC so long as no user level references |
| // to the object exist. If m_ctxt were not dynamic then its |
| // presence in the global context list would be enough to keep |
| // this object alive indefinitely. An alternative to allocating |
| // room for this struct explicitly would be to mash it into the |
| // base of the stack being allocated below. However, doing so |
| // requires too much special logic to be worthwhile. |
| m_ctxt = new StackContext; |
| |
| version (Windows) |
| { |
| // reserve memory for stack |
| m_pmem = VirtualAlloc( null, |
| sz + guardPageSize, |
| MEM_RESERVE, |
| PAGE_NOACCESS ); |
| if ( !m_pmem ) |
| onOutOfMemoryError(); |
| |
| version (StackGrowsDown) |
| { |
| void* stack = m_pmem + guardPageSize; |
| void* guard = m_pmem; |
| void* pbase = stack + sz; |
| } |
| else |
| { |
| void* stack = m_pmem; |
| void* guard = m_pmem + sz; |
| void* pbase = stack; |
| } |
| |
| // allocate reserved stack segment |
| stack = VirtualAlloc( stack, |
| sz, |
| MEM_COMMIT, |
| PAGE_READWRITE ); |
| if ( !stack ) |
| onOutOfMemoryError(); |
| |
| if (guardPageSize) |
| { |
| // allocate reserved guard page |
| guard = VirtualAlloc( guard, |
| guardPageSize, |
| MEM_COMMIT, |
| PAGE_READWRITE | PAGE_GUARD ); |
| if ( !guard ) |
| onOutOfMemoryError(); |
| } |
| |
| m_ctxt.bstack = pbase; |
| m_ctxt.tstack = pbase; |
| m_size = sz; |
| } |
| else |
| { |
| version (Posix) import core.sys.posix.sys.mman : MAP_ANON, MAP_FAILED, MAP_PRIVATE, mmap, |
| mprotect, PROT_NONE, PROT_READ, PROT_WRITE; |
| version (OpenBSD) import core.sys.posix.sys.mman : MAP_STACK; |
| |
| static if ( __traits( compiles, ucontext_t ) ) |
| { |
| // Stack size must be at least the minimum allowable by the OS. |
| if (sz < MINSIGSTKSZ) |
| sz = MINSIGSTKSZ; |
| } |
| |
| static if ( __traits( compiles, mmap ) ) |
| { |
| // Allocate more for the memory guard |
| sz += guardPageSize; |
| |
| int mmap_flags = MAP_PRIVATE | MAP_ANON; |
| version (OpenBSD) |
| mmap_flags |= MAP_STACK; |
| |
| m_pmem = mmap( null, |
| sz, |
| PROT_READ | PROT_WRITE, |
| mmap_flags, |
| -1, |
| 0 ); |
| if ( m_pmem == MAP_FAILED ) |
| m_pmem = null; |
| } |
| else static if ( __traits( compiles, valloc ) ) |
| { |
| m_pmem = valloc( sz ); |
| } |
| else |
| { |
| import core.stdc.stdlib : malloc; |
| |
| m_pmem = malloc( sz ); |
| } |
| |
| if ( !m_pmem ) |
| onOutOfMemoryError(); |
| |
| version (StackGrowsDown) |
| { |
| m_ctxt.bstack = m_pmem + sz; |
| m_ctxt.tstack = m_pmem + sz; |
| void* guard = m_pmem; |
| } |
| else |
| { |
| m_ctxt.bstack = m_pmem; |
| m_ctxt.tstack = m_pmem; |
| void* guard = m_pmem + sz - guardPageSize; |
| } |
| m_size = sz; |
| |
| static if ( __traits( compiles, mmap ) ) |
| { |
| if (guardPageSize) |
| { |
| // protect end of stack |
| if ( mprotect(guard, guardPageSize, PROT_NONE) == -1 ) |
| abort(); |
| } |
| } |
| else |
| { |
| // Supported only for mmap allocated memory - results are |
| // undefined if applied to memory not obtained by mmap |
| } |
| } |
| |
| ThreadBase.add( m_ctxt ); |
| } |
| |
| |
| // |
| // Free this fiber's stack. |
| // |
| final override void freeStack() nothrow @nogc |
| in(m_pmem) |
| in(m_ctxt) |
| { |
| // NOTE: m_ctxt is guaranteed to be alive because it is held in the |
| // global context list. |
| ThreadBase.slock.lock_nothrow(); |
| scope(exit) ThreadBase.slock.unlock_nothrow(); |
| ThreadBase.remove( m_ctxt ); |
| |
| version (Windows) |
| { |
| VirtualFree( m_pmem, 0, MEM_RELEASE ); |
| } |
| else |
| { |
| import core.sys.posix.sys.mman : mmap, munmap; |
| |
| static if ( __traits( compiles, mmap ) ) |
| { |
| munmap( m_pmem, m_size ); |
| } |
| else |
| { |
| free( m_pmem ); |
| } |
| } |
| m_pmem = null; |
| m_ctxt = null; |
| } |
| |
| |
| // |
| // Initialize the allocated stack. |
| // Look above the definition of 'class Fiber' for some information about the implementation of this routine |
| // |
| final override void initStack() nothrow @nogc |
| in |
| { |
| assert( m_ctxt.tstack && m_ctxt.tstack == m_ctxt.bstack ); |
| assert( cast(size_t) m_ctxt.bstack % (void*).sizeof == 0 ); |
| } |
| do |
| { |
| void* pstack = m_ctxt.tstack; |
| scope( exit ) m_ctxt.tstack = pstack; |
| |
| void push( size_t val ) nothrow |
| { |
| version (StackGrowsDown) |
| { |
| pstack -= size_t.sizeof; |
| *(cast(size_t*) pstack) = val; |
| } |
| else |
| { |
| pstack += size_t.sizeof; |
| *(cast(size_t*) pstack) = val; |
| } |
| } |
| |
| // NOTE: On OS X the stack must be 16-byte aligned according |
| // to the IA-32 call spec. For x86_64 the stack also needs to |
| // be aligned to 16-byte according to SysV AMD64 ABI. |
| version (AlignFiberStackTo16Byte) |
| { |
| version (StackGrowsDown) |
| { |
| pstack = cast(void*)(cast(size_t)(pstack) - (cast(size_t)(pstack) & 0x0F)); |
| } |
| else |
| { |
| pstack = cast(void*)(cast(size_t)(pstack) + (cast(size_t)(pstack) & 0x0F)); |
| } |
| } |
| |
| version (AsmX86_Windows) |
| { |
| version (StackGrowsDown) {} else static assert( false ); |
| |
| // On Windows Server 2008 and 2008 R2, an exploit mitigation |
| // technique known as SEHOP is activated by default. To avoid |
| // hijacking of the exception handler chain, the presence of a |
| // Windows-internal handler (ntdll.dll!FinalExceptionHandler) at |
| // its end is tested by RaiseException. If it is not present, all |
| // handlers are disregarded, and the program is thus aborted |
| // (see http://blogs.technet.com/b/srd/archive/2009/02/02/ |
| // preventing-the-exploitation-of-seh-overwrites-with-sehop.aspx). |
| // For new threads, this handler is installed by Windows immediately |
| // after creation. To make exception handling work in fibers, we |
| // have to insert it for our new stacks manually as well. |
| // |
| // To do this, we first determine the handler by traversing the SEH |
| // chain of the current thread until its end, and then construct a |
| // registration block for the last handler on the newly created |
| // thread. We then continue to push all the initial register values |
| // for the first context switch as for the other implementations. |
| // |
| // Note that this handler is never actually invoked, as we install |
| // our own one on top of it in the fiber entry point function. |
| // Thus, it should not have any effects on OSes not implementing |
| // exception chain verification. |
| |
| alias fp_t = void function(); // Actual signature not relevant. |
| static struct EXCEPTION_REGISTRATION |
| { |
| EXCEPTION_REGISTRATION* next; // sehChainEnd if last one. |
| fp_t handler; |
| } |
| enum sehChainEnd = cast(EXCEPTION_REGISTRATION*) 0xFFFFFFFF; |
| |
| __gshared fp_t finalHandler = null; |
| if ( finalHandler is null ) |
| { |
| static EXCEPTION_REGISTRATION* fs0() nothrow |
| { |
| asm pure nothrow @nogc |
| { |
| naked; |
| mov EAX, FS:[0]; |
| ret; |
| } |
| } |
| auto reg = fs0(); |
| while ( reg.next != sehChainEnd ) reg = reg.next; |
| |
| // Benign races are okay here, just to avoid re-lookup on every |
| // fiber creation. |
| finalHandler = reg.handler; |
| } |
| |
| // When linking with /safeseh (supported by LDC, but not DMD) |
| // the exception chain must not extend to the very top |
| // of the stack, otherwise the exception chain is also considered |
| // invalid. Reserving additional 4 bytes at the top of the stack will |
| // keep the EXCEPTION_REGISTRATION below that limit |
| size_t reserve = EXCEPTION_REGISTRATION.sizeof + 4; |
| pstack -= reserve; |
| *(cast(EXCEPTION_REGISTRATION*)pstack) = |
| EXCEPTION_REGISTRATION( sehChainEnd, finalHandler ); |
| auto pChainEnd = pstack; |
| |
| push( cast(size_t) &fiber_entryPoint ); // EIP |
| push( cast(size_t) m_ctxt.bstack - reserve ); // EBP |
| push( 0x00000000 ); // EDI |
| push( 0x00000000 ); // ESI |
| push( 0x00000000 ); // EBX |
| push( cast(size_t) pChainEnd ); // FS:[0] |
| push( cast(size_t) m_ctxt.bstack ); // FS:[4] |
| push( cast(size_t) m_ctxt.bstack - m_size ); // FS:[8] |
| push( 0x00000000 ); // EAX |
| } |
| else version (AsmX86_64_Windows) |
| { |
| // Using this trampoline instead of the raw fiber_entryPoint |
| // ensures that during context switches, source and destination |
| // stacks have the same alignment. Otherwise, the stack would need |
| // to be shifted by 8 bytes for the first call, as fiber_entryPoint |
| // is an actual function expecting a stack which is not aligned |
| // to 16 bytes. |
| static void trampoline() |
| { |
| asm pure nothrow @nogc |
| { |
| naked; |
| sub RSP, 32; // Shadow space (Win64 calling convention) |
| call fiber_entryPoint; |
| xor RCX, RCX; // This should never be reached, as |
| jmp RCX; // fiber_entryPoint must never return. |
| } |
| } |
| |
| push( cast(size_t) &trampoline ); // RIP |
| push( 0x00000000_00000000 ); // RBP |
| push( 0x00000000_00000000 ); // R12 |
| push( 0x00000000_00000000 ); // R13 |
| push( 0x00000000_00000000 ); // R14 |
| push( 0x00000000_00000000 ); // R15 |
| push( 0x00000000_00000000 ); // RDI |
| push( 0x00000000_00000000 ); // RSI |
| push( 0x00000000_00000000 ); // XMM6 (high) |
| push( 0x00000000_00000000 ); // XMM6 (low) |
| push( 0x00000000_00000000 ); // XMM7 (high) |
| push( 0x00000000_00000000 ); // XMM7 (low) |
| push( 0x00000000_00000000 ); // XMM8 (high) |
| push( 0x00000000_00000000 ); // XMM8 (low) |
| push( 0x00000000_00000000 ); // XMM9 (high) |
| push( 0x00000000_00000000 ); // XMM9 (low) |
| push( 0x00000000_00000000 ); // XMM10 (high) |
| push( 0x00000000_00000000 ); // XMM10 (low) |
| push( 0x00000000_00000000 ); // XMM11 (high) |
| push( 0x00000000_00000000 ); // XMM11 (low) |
| push( 0x00000000_00000000 ); // XMM12 (high) |
| push( 0x00000000_00000000 ); // XMM12 (low) |
| push( 0x00000000_00000000 ); // XMM13 (high) |
| push( 0x00000000_00000000 ); // XMM13 (low) |
| push( 0x00000000_00000000 ); // XMM14 (high) |
| push( 0x00000000_00000000 ); // XMM14 (low) |
| push( 0x00000000_00000000 ); // XMM15 (high) |
| push( 0x00000000_00000000 ); // XMM15 (low) |
| push( 0x00000000_00000000 ); // RBX |
| push( 0xFFFFFFFF_FFFFFFFF ); // GS:[0] |
| version (StackGrowsDown) |
| { |
| push( cast(size_t) m_ctxt.bstack ); // GS:[8] |
| push( cast(size_t) m_ctxt.bstack - m_size ); // GS:[16] |
| } |
| else |
| { |
| push( cast(size_t) m_ctxt.bstack ); // GS:[8] |
| push( cast(size_t) m_ctxt.bstack + m_size ); // GS:[16] |
| } |
| } |
| else version (AsmX86_Posix) |
| { |
| push( 0x00000000 ); // Return address of fiber_entryPoint call |
| push( cast(size_t) &fiber_entryPoint ); // EIP |
| push( cast(size_t) m_ctxt.bstack ); // EBP |
| push( 0x00000000 ); // EDI |
| push( 0x00000000 ); // ESI |
| push( 0x00000000 ); // EBX |
| push( 0x00000000 ); // EAX |
| } |
| else version (AsmX86_64_Posix) |
| { |
| push( 0x00000000_00000000 ); // Return address of fiber_entryPoint call |
| push( cast(size_t) &fiber_entryPoint ); // RIP |
| push( cast(size_t) m_ctxt.bstack ); // RBP |
| push( 0x00000000_00000000 ); // RBX |
| push( 0x00000000_00000000 ); // R12 |
| push( 0x00000000_00000000 ); // R13 |
| push( 0x00000000_00000000 ); // R14 |
| push( 0x00000000_00000000 ); // R15 |
| } |
| else version (AsmPPC_Posix) |
| { |
| version (StackGrowsDown) |
| { |
| pstack -= int.sizeof * 5; |
| } |
| else |
| { |
| pstack += int.sizeof * 5; |
| } |
| |
| push( cast(size_t) &fiber_entryPoint ); // link register |
| push( 0x00000000 ); // control register |
| push( 0x00000000 ); // old stack pointer |
| |
| // GPR values |
| version (StackGrowsDown) |
| { |
| pstack -= int.sizeof * 20; |
| } |
| else |
| { |
| pstack += int.sizeof * 20; |
| } |
| |
| assert( (cast(size_t) pstack & 0x0f) == 0 ); |
| } |
| else version (AsmPPC_Darwin) |
| { |
| version (StackGrowsDown) {} |
| else static assert(false, "PowerPC Darwin only supports decrementing stacks"); |
| |
| uint wsize = size_t.sizeof; |
| |
| // linkage + regs + FPRs + VRs |
| uint space = 8 * wsize + 20 * wsize + 18 * 8 + 12 * 16; |
| (cast(ubyte*)pstack - space)[0 .. space] = 0; |
| |
| pstack -= wsize * 6; |
| *cast(size_t*)pstack = cast(size_t) &fiber_entryPoint; // LR |
| pstack -= wsize * 22; |
| |
| // On Darwin PPC64 pthread self is in R13 (which is reserved). |
| // At present, it is not safe to migrate fibers between threads, but if that |
| // changes, then updating the value of R13 will also need to be handled. |
| version (PPC64) |
| *cast(size_t*)(pstack + wsize) = cast(size_t) ThreadBase.getThis().m_addr; |
| assert( (cast(size_t) pstack & 0x0f) == 0 ); |
| } |
| else version (AsmMIPS_O32_Posix) |
| { |
| version (StackGrowsDown) {} |
| else static assert(0); |
| |
| /* We keep the FP registers and the return address below |
| * the stack pointer, so they don't get scanned by the |
| * GC. The last frame before swapping the stack pointer is |
| * organized like the following. |
| * |
| * |-----------|<= frame pointer |
| * | $gp | |
| * | $s0-8 | |
| * |-----------|<= stack pointer |
| * | $ra | |
| * | align(8) | |
| * | $f20-30 | |
| * |-----------| |
| * |
| */ |
| enum SZ_GP = 10 * size_t.sizeof; // $gp + $s0-8 |
| enum SZ_RA = size_t.sizeof; // $ra |
| version (MIPS_HardFloat) |
| { |
| enum SZ_FP = 6 * 8; // $f20-30 |
| enum ALIGN = -(SZ_FP + SZ_RA) & (8 - 1); |
| } |
| else |
| { |
| enum SZ_FP = 0; |
| enum ALIGN = 0; |
| } |
| |
| enum BELOW = SZ_FP + ALIGN + SZ_RA; |
| enum ABOVE = SZ_GP; |
| enum SZ = BELOW + ABOVE; |
| |
| (cast(ubyte*)pstack - SZ)[0 .. SZ] = 0; |
| pstack -= ABOVE; |
| *cast(size_t*)(pstack - SZ_RA) = cast(size_t)&fiber_entryPoint; |
| } |
| else version (AsmMIPS_N64_Posix) |
| { |
| version (StackGrowsDown) {} |
| else static assert(0); |
| |
| /* We keep the FP registers and the return address below |
| * the stack pointer, so they don't get scanned by the |
| * GC. The last frame before swapping the stack pointer is |
| * organized like the following. |
| * |
| * |-----------|<= frame pointer |
| * | $fp/$gp | |
| * | $s0-7 | |
| * |-----------|<= stack pointer |
| * | $ra | |
| * | $f24-31 | |
| * |-----------| |
| * |
| */ |
| enum SZ_GP = 10 * size_t.sizeof; // $fp + $gp + $s0-7 |
| enum SZ_RA = size_t.sizeof; // $ra |
| version (MIPS_HardFloat) |
| { |
| enum SZ_FP = 8 * double.sizeof; // $f24-31 |
| } |
| else |
| { |
| enum SZ_FP = 0; |
| } |
| |
| enum BELOW = SZ_FP + SZ_RA; |
| enum ABOVE = SZ_GP; |
| enum SZ = BELOW + ABOVE; |
| |
| (cast(ubyte*)pstack - SZ)[0 .. SZ] = 0; |
| pstack -= ABOVE; |
| *cast(size_t*)(pstack - SZ_RA) = cast(size_t)&fiber_entryPoint; |
| } |
| else version (AsmLoongArch64_Posix) |
| { |
| // Like others, FP registers and return address ($r1) are kept |
| // below the saved stack top (tstack) to hide from GC scanning. |
| // fiber_switchContext expects newp sp to look like this: |
| // 10: $r21 (reserved) |
| // 9: $r22 (frame pointer) |
| // 8: $r23 |
| // ... |
| // 0: $r31 <-- newp tstack |
| // -1: $r1 (return address) [&fiber_entryPoint] |
| // -2: $f24 |
| // ... |
| // -9: $f31 |
| |
| version (StackGrowsDown) {} |
| else |
| static assert(false, "Only full descending stacks supported on LoongArch64"); |
| |
| // Only need to set return address ($r1). Everything else is fine |
| // zero initialized. |
| pstack -= size_t.sizeof * 11; // skip past space reserved for $r21-$r31 |
| push(cast(size_t) &fiber_entryPoint); |
| pstack += size_t.sizeof; // adjust sp (newp) above lr |
| } |
| else version (AsmAArch64_Posix) |
| { |
| // Like others, FP registers and return address (lr) are kept |
| // below the saved stack top (tstack) to hide from GC scanning. |
| // fiber_switchContext expects newp sp to look like this: |
| // 19: x19 |
| // ... |
| // 9: x29 (fp) <-- newp tstack |
| // 8: x30 (lr) [&fiber_entryPoint] |
| // 7: d8 |
| // ... |
| // 0: d15 |
| |
| version (StackGrowsDown) {} |
| else |
| static assert(false, "Only full descending stacks supported on AArch64"); |
| |
| // Only need to set return address (lr). Everything else is fine |
| // zero initialized. |
| pstack -= size_t.sizeof * 11; // skip past x19-x29 |
| push(cast(size_t) &fiber_trampoline); // see threadasm.S for docs |
| pstack += size_t.sizeof; // adjust sp (newp) above lr |
| } |
| else version (AsmARM_Posix) |
| { |
| /* We keep the FP registers and the return address below |
| * the stack pointer, so they don't get scanned by the |
| * GC. The last frame before swapping the stack pointer is |
| * organized like the following. |
| * |
| * | |-----------|<= 'frame starts here' |
| * | | fp | (the actual frame pointer, r11 isn't |
| * | | r10-r4 | updated and still points to the previous frame) |
| * | |-----------|<= stack pointer |
| * | | lr | |
| * | | 4byte pad | |
| * | | d15-d8 |(if FP supported) |
| * | |-----------| |
| * Y |
| * stack grows down: The pointer value here is smaller than some lines above |
| */ |
| // frame pointer can be zero, r10-r4 also zero initialized |
| version (StackGrowsDown) |
| pstack -= int.sizeof * 8; |
| else |
| static assert(false, "Only full descending stacks supported on ARM"); |
| |
| // link register |
| push( cast(size_t) &fiber_entryPoint ); |
| /* |
| * We do not push padding and d15-d8 as those are zero initialized anyway |
| * Position the stack pointer above the lr register |
| */ |
| pstack += int.sizeof * 1; |
| } |
| else version (GNU_AsmX86_Windows) |
| { |
| version (StackGrowsDown) {} else static assert( false ); |
| |
| // Currently, MinGW doesn't utilize SEH exceptions. |
| // See DMD AsmX86_Windows If this code ever becomes fails and SEH is used. |
| |
| push( 0x00000000 ); // Return address of fiber_entryPoint call |
| push( cast(size_t) &fiber_entryPoint ); // EIP |
| push( 0x00000000 ); // EBP |
| push( 0x00000000 ); // EDI |
| push( 0x00000000 ); // ESI |
| push( 0x00000000 ); // EBX |
| push( 0xFFFFFFFF ); // FS:[0] - Current SEH frame |
| push( cast(size_t) m_ctxt.bstack ); // FS:[4] - Top of stack |
| push( cast(size_t) m_ctxt.bstack - m_size ); // FS:[8] - Bottom of stack |
| push( 0x00000000 ); // EAX |
| } |
| else version (GNU_AsmX86_64_Windows) |
| { |
| push( 0x00000000_00000000 ); // Return address of fiber_entryPoint call |
| push( cast(size_t) &fiber_entryPoint ); // RIP |
| push( 0x00000000_00000000 ); // RBP |
| push( 0x00000000_00000000 ); // RBX |
| push( 0x00000000_00000000 ); // R12 |
| push( 0x00000000_00000000 ); // R13 |
| push( 0x00000000_00000000 ); // R14 |
| push( 0x00000000_00000000 ); // R15 |
| push( 0xFFFFFFFF_FFFFFFFF ); // GS:[0] - Current SEH frame |
| version (StackGrowsDown) |
| { |
| push( cast(size_t) m_ctxt.bstack ); // GS:[8] - Top of stack |
| push( cast(size_t) m_ctxt.bstack - m_size ); // GS:[16] - Bottom of stack |
| } |
| else |
| { |
| push( cast(size_t) m_ctxt.bstack ); // GS:[8] - Top of stack |
| push( cast(size_t) m_ctxt.bstack + m_size ); // GS:[16] - Bottom of stack |
| } |
| } |
| else static if ( __traits( compiles, ucontext_t ) ) |
| { |
| getcontext( &m_utxt ); |
| m_utxt.uc_stack.ss_sp = m_pmem; |
| m_utxt.uc_stack.ss_size = m_size; |
| makecontext( &m_utxt, &fiber_entryPoint, 0 ); |
| // NOTE: If ucontext is being used then the top of the stack will |
| // be a pointer to the ucontext_t struct for that fiber. |
| push( cast(size_t) &m_utxt ); |
| } |
| else |
| static assert(0, "Not implemented"); |
| } |
| } |
| |
| |
| version (AsmX86_64_Windows) |
| { |
| // Test Windows x64 calling convention |
| unittest |
| { |
| void testNonvolatileRegister(alias REG)() |
| { |
| auto zeroRegister = new Fiber(() { |
| mixin("asm pure nothrow @nogc { naked; xor "~REG~", "~REG~"; ret; }"); |
| }); |
| long after; |
| |
| mixin("asm pure nothrow @nogc { mov "~REG~", 0xFFFFFFFFFFFFFFFF; }"); |
| zeroRegister.call(); |
| mixin("asm pure nothrow @nogc { mov after, "~REG~"; }"); |
| |
| assert(after == -1); |
| } |
| |
| void testNonvolatileRegisterSSE(alias REG)() |
| { |
| auto zeroRegister = new Fiber(() { |
| mixin("asm pure nothrow @nogc { naked; xorpd "~REG~", "~REG~"; ret; }"); |
| }); |
| long[2] before = [0xFFFFFFFF_FFFFFFFF, 0xFFFFFFFF_FFFFFFFF], after; |
| |
| mixin("asm pure nothrow @nogc { movdqu "~REG~", before; }"); |
| zeroRegister.call(); |
| mixin("asm pure nothrow @nogc { movdqu after, "~REG~"; }"); |
| |
| assert(before == after); |
| } |
| |
| testNonvolatileRegister!("R12")(); |
| testNonvolatileRegister!("R13")(); |
| testNonvolatileRegister!("R14")(); |
| testNonvolatileRegister!("R15")(); |
| testNonvolatileRegister!("RDI")(); |
| testNonvolatileRegister!("RSI")(); |
| testNonvolatileRegister!("RBX")(); |
| |
| testNonvolatileRegisterSSE!("XMM6")(); |
| testNonvolatileRegisterSSE!("XMM7")(); |
| testNonvolatileRegisterSSE!("XMM8")(); |
| testNonvolatileRegisterSSE!("XMM9")(); |
| testNonvolatileRegisterSSE!("XMM10")(); |
| testNonvolatileRegisterSSE!("XMM11")(); |
| testNonvolatileRegisterSSE!("XMM12")(); |
| testNonvolatileRegisterSSE!("XMM13")(); |
| testNonvolatileRegisterSSE!("XMM14")(); |
| testNonvolatileRegisterSSE!("XMM15")(); |
| } |
| } |
| |
| |
| version (D_InlineAsm_X86_64) |
| { |
| unittest |
| { |
| void testStackAlignment() |
| { |
| void* pRSP; |
| asm pure nothrow @nogc |
| { |
| mov pRSP, RSP; |
| } |
| assert((cast(size_t)pRSP & 0xF) == 0); |
| } |
| |
| auto fib = new Fiber(&testStackAlignment); |
| fib.call(); |
| } |
| } |
