powerpc/kernel/static_call.c

0001 // SPDX-License-Identifier: GPL-2.0
0002 #include <linux/memory.h>
0003 #include <linux/static_call.h>
0004
0005 #include <asm/code-patching.h>
0006
0007 void arch_static_call_transform(void *site, void *tramp, void *func, bool tail)
0008 {
0009     int err;
0010     bool is_ret0 = (func == __static_call_return0);
0011     unsigned long target = (unsigned long)(is_ret0 ? tramp + PPC_SCT_RET0 : func);
0012     bool is_short = is_offset_in_branch_range((long)target - (long)tramp);
0013
0014     if (!tramp)
0015         return;
0016
0017     mutex_lock(&text_mutex);
0018
0019     if (func && !is_short) {
0020         err = patch_instruction(tramp + PPC_SCT_DATA, ppc_inst(target));
0021         if (err)
0022             goto out;
0023     }
0024
0025     if (!func)
0026         err = patch_instruction(tramp, ppc_inst(PPC_RAW_BLR()));
0027     else if (is_short)
0028         err = patch_branch(tramp, target, 0);
0029     else
0030         err = patch_instruction(tramp, ppc_inst(PPC_RAW_NOP()));
0031 out:
0032     mutex_unlock(&text_mutex);
0033
0034     if (err)
0035         panic("%s: patching failed %pS at %pS\n", __func__, func, tramp);
0036 }
0037 EXPORT_SYMBOL_GPL(arch_static_call_transform);