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Merge pull request #1401 from darlinghq/mldr_thread_entry_rework
Rewrite darling_thread_entry Inline Assembly
authored by
CuriousTommy
and committed by
GitHub
82525f6d
98c5c8ab
+67
-37
+1
-1
src/startup/CMakeLists.txt
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-1
src/startup/CMakeLists.txt
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enable_language(C ASM)
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set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -std=c11 -ggdb -O0")
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set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -std=gnu11 -ggdb -O0")
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set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11")
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#set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} -Wl,-Ttext-segment,0x400000 -Wl,-Tbss,0x410000 -Wl,-Tdata,0x420000")
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add_definitions(-DINSTALL_PREFIX="${CMAKE_INSTALL_PREFIX}" -D_GNU_SOURCE -DMLDR_BUILD)
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src/startup/mldr/elfcalls/threads.c
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src/startup/mldr/elfcalls/threads.c
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#define DEFAULT_DTHREAD_GUARD_SIZE 0x1000
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static inline void *align_16(uintptr_t ptr) {
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return (void *) ((uintptr_t) ptr & ~(uintptr_t) 15);
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}
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static dthread_t dthread_structure_init(dthread_t dthread, size_t guard_size, void* stack_addr, size_t stack_size, void* base_addr, size_t total_size) {
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// the pthread signature is the address of the pthread XORed with the "pointer munge" token passed in by the kernel
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// since the LKM doesn't pass in a token, it's always zero, so the signature is equal to just the address
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return NULL;
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}
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void *stack_ptr = align_16(args.stack_addr);
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// No additional function calls should occur beyond this point. Otherwise, we will risk our
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// registers being call-clobbered. I recommend reading the following doc for more details:
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// https://gcc.gnu.org/onlinedocs/gcc/Local-Register-Variables.html
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#if __x86_64__
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register void* arg1 asm("rdi") = args.pth;
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register int arg2 asm("esi") = args.port;
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register uintptr_t arg3 asm("rdx") = args.real_entry_point;
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register uintptr_t arg4 asm("rcx") = args.arg1;
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register uintptr_t arg5 asm("r8") = args.arg2;
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register uintptr_t arg6 asm("r9") = args.arg3;
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#elif __i386__
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uintptr_t arg3 = args.real_entry_point;
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#endif
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if (arg3 == 0) {
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arg3 = (long) args.stack_bottom;
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}
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#ifdef __x86_64__
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__asm__ __volatile__ (
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"movq %1, %%rdi\n"
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"movq 80(%0), %%rsp\n"
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"movq 40(%0), %%rsi\n"
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"movq 8(%0), %%rdx\n"
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"testq %%rdx, %%rdx\n"
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"jnz 1f\n"
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"movq 72(%0), %%rdx\n" // wqthread hack: if 3rd arg is null, we pass the stack bottom
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"1:\n"
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"movq 16(%0), %%rcx\n"
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"movq 24(%0), %%r8\n"
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"movq 32(%0), %%r9\n"
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"movq %%rdi, 56(%0)\n"
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"movq (%0), %%rax\n"
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"andq $-0x10, %%rsp\n"
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"pushq $0\n"
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"pushq $0\n"
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"jmpq *%%rax\n"
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:: "a" (&args), "di" (args.pth));
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asm volatile(
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// Zero out the frame base register.
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"xorq %%rbp, %%rbp\n"
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// Switch to the new stack.
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"movq %[stack_ptr], %%rsp\n"
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// Push a fake return address.
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"pushq $0\n"
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// Jump to the entry point.
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"jmp *%[entry_point]" ::
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// Function arguments
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"r"(arg1),"r"(arg2),"r"(arg3),"r"(arg4),"r"(arg5),"r"(arg6),
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[entry_point] "r"(args.entry_point),
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[stack_ptr] "r"(stack_ptr)
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);
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#elif defined(__i386__) // args in eax, ebx, ecx, edx, edi, esi
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__asm__ __volatile__ (
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"movl (%0), %%eax\n"
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"movl 40(%0), %%esp\n"
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"pushl %%eax\n" // address to be jumped to
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"movl %1, 28(%0)\n"
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"movl %1, %%eax\n" // 1st arg
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"movl 20(%0), %%ebx\n" // 2nd arg
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"movl 8(%0), %%edx\n" // 4th arg
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"movl 12(%0), %%edi\n" // 5th arg
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"movl 16(%0), %%esi\n" // 6th arg
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"movl 4(%0), %%ecx\n" // 3rd arg
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"testl %%ecx, %%ecx\n" // FIXME: clobbered ecx!
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"jnz 1f\n"
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"movl 36(%0), %%ecx\n" // if the 3rd argument is null, pass the stack bottom
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"1:\n"
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"ret\n" // Jump to the address pushed at the beginning
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:: "c" (&args), "d" (args.pth));
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// Zero out the frame base register.
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"xorl %%ebp, %%ebp\n"
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// Switch to the new stack.
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"movl %[stack_ptr], %%esp\n"
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// Make sure stack is 16 aligned (before we push the fake return address)
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"sub $8, %%esp\n"
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// Unlike x86_64, all function arguments must be stored in the stack
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"pushl 16(%[args])\n" // 6th argument | args.arg3
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"pushl 12(%[args])\n" // 5th argument | args.arg2
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"pushl 8(%[args])\n" // 4th argument | args.arg1
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"pushl %[arg3]\n" // 3rd argument | args3
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"pushl 20(%[args])\n" // 2nd argument | args.port
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"pushl 28(%[args])\n" // 1st argument | args.pth
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// Push a fake return address.
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"pushl $0\n"
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// Jump to the entry point.
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"jmp *%[entry_point]" ::
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// Function arguments to push to the stack.
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[args] "r"(&args), [arg3]"r"(arg3),
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[entry_point] "r"(args.entry_point),
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[stack_ptr] "r"(stack_ptr)
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);
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#else
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#error Not implemented
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#error Not implemented
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// args.entry_point(args.pth, args.port, args.real_entry_point, args.arg1, args.arg2, args.arg3);
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#endif
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__builtin_unreachable();
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}