1 // SPDX-License-Identifier: GPL-2.0 2 #include <linux/memory.h> 3 #include <linux/static_call.h> 4 5 #include <asm/text-patching.h> 6 7 void arch_static_call_transform(void *site, void *tramp, void *func, bool tail) 8 { 9 int err; 10 bool is_ret0 = (func == __static_call_return0); 11 unsigned long _tramp = (unsigned long)tramp; 12 unsigned long _func = (unsigned long)func; 13 unsigned long _ret0 = _tramp + PPC_SCT_RET0; 14 bool is_short = is_offset_in_branch_range((long)func - (long)(site ? : tramp)); 15 16 mutex_lock(&text_mutex); 17 18 if (site && tail) { 19 if (!func) 20 err = patch_instruction(site, ppc_inst(PPC_RAW_BLR())); 21 else if (is_ret0) 22 err = patch_branch(site, _ret0, 0); 23 else if (is_short) 24 err = patch_branch(site, _func, 0); 25 else if (tramp) 26 err = patch_branch(site, _tramp, 0); 27 else 28 err = 0; 29 } else if (site) { 30 if (!func) 31 err = patch_instruction(site, ppc_inst(PPC_RAW_NOP())); 32 else if (is_ret0) 33 err = patch_instruction(site, ppc_inst(PPC_RAW_LI(_R3, 0))); 34 else if (is_short) 35 err = patch_branch(site, _func, BRANCH_SET_LINK); 36 else if (tramp) 37 err = patch_branch(site, _tramp, BRANCH_SET_LINK); 38 else 39 err = 0; 40 } else if (tramp) { 41 if (func && !is_short) { 42 err = patch_ulong(tramp + PPC_SCT_DATA, _func); 43 if (err) 44 goto out; 45 } 46 47 if (!func) 48 err = patch_instruction(tramp, ppc_inst(PPC_RAW_BLR())); 49 else if (is_ret0) 50 err = patch_branch(tramp, _ret0, 0); 51 else if (is_short) 52 err = patch_branch(tramp, _func, 0); 53 else 54 err = patch_instruction(tramp, ppc_inst(PPC_RAW_NOP())); 55 } else { 56 err = 0; 57 } 58 59 out: 60 mutex_unlock(&text_mutex); 61 62 if (err) 63 panic("%s: patching failed %pS at %pS\n", __func__, func, tramp); 64 } 65 EXPORT_SYMBOL_GPL(arch_static_call_transform); 66