1*0b57cec5SDimitry Andric //===----- trampoline_setup.c - Implement __trampoline_setup -------------===// 2*0b57cec5SDimitry Andric // 3*0b57cec5SDimitry Andric // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4*0b57cec5SDimitry Andric // See https://llvm.org/LICENSE.txt for license information. 5*0b57cec5SDimitry Andric // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6*0b57cec5SDimitry Andric // 7*0b57cec5SDimitry Andric //===----------------------------------------------------------------------===// 8*0b57cec5SDimitry Andric 9*0b57cec5SDimitry Andric #include "int_lib.h" 10*0b57cec5SDimitry Andric 11*0b57cec5SDimitry Andric extern void __clear_cache(void *start, void *end); 12*0b57cec5SDimitry Andric 13*0b57cec5SDimitry Andric // The ppc compiler generates calls to __trampoline_setup() when creating 14*0b57cec5SDimitry Andric // trampoline functions on the stack for use with nested functions. 15*0b57cec5SDimitry Andric // This function creates a custom 40-byte trampoline function on the stack 16*0b57cec5SDimitry Andric // which loads r11 with a pointer to the outer function's locals 17*0b57cec5SDimitry Andric // and then jumps to the target nested function. 18*0b57cec5SDimitry Andric 19*0b57cec5SDimitry Andric #if __ppc__ && !defined(__powerpc64__) 20*0b57cec5SDimitry Andric COMPILER_RT_ABI void __trampoline_setup(uint32_t *trampOnStack, 21*0b57cec5SDimitry Andric int trampSizeAllocated, 22*0b57cec5SDimitry Andric const void *realFunc, void *localsPtr) { 23*0b57cec5SDimitry Andric // should never happen, but if compiler did not allocate 24*0b57cec5SDimitry Andric // enough space on stack for the trampoline, abort 25*0b57cec5SDimitry Andric if (trampSizeAllocated < 40) 26*0b57cec5SDimitry Andric compilerrt_abort(); 27*0b57cec5SDimitry Andric 28*0b57cec5SDimitry Andric // create trampoline 29*0b57cec5SDimitry Andric trampOnStack[0] = 0x7c0802a6; // mflr r0 30*0b57cec5SDimitry Andric trampOnStack[1] = 0x4800000d; // bl Lbase 31*0b57cec5SDimitry Andric trampOnStack[2] = (uint32_t)realFunc; 32*0b57cec5SDimitry Andric trampOnStack[3] = (uint32_t)localsPtr; 33*0b57cec5SDimitry Andric trampOnStack[4] = 0x7d6802a6; // Lbase: mflr r11 34*0b57cec5SDimitry Andric trampOnStack[5] = 0x818b0000; // lwz r12,0(r11) 35*0b57cec5SDimitry Andric trampOnStack[6] = 0x7c0803a6; // mtlr r0 36*0b57cec5SDimitry Andric trampOnStack[7] = 0x7d8903a6; // mtctr r12 37*0b57cec5SDimitry Andric trampOnStack[8] = 0x816b0004; // lwz r11,4(r11) 38*0b57cec5SDimitry Andric trampOnStack[9] = 0x4e800420; // bctr 39*0b57cec5SDimitry Andric 40*0b57cec5SDimitry Andric // clear instruction cache 41*0b57cec5SDimitry Andric __clear_cache(trampOnStack, &trampOnStack[10]); 42*0b57cec5SDimitry Andric } 43*0b57cec5SDimitry Andric #endif // __ppc__ && !defined(__powerpc64__) 44