xref: /linux/arch/powerpc/kernel/static_call.c (revision c532de5a67a70f8533d495f8f2aaa9a0491c3ad0)
1 // SPDX-License-Identifier: GPL-2.0
2 #include <linux/memory.h>
3 #include <linux/static_call.h>
4 
5 #include <asm/code-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 target = (unsigned long)(is_ret0 ? tramp + PPC_SCT_RET0 : func);
12 	bool is_short = is_offset_in_branch_range((long)target - (long)tramp);
13 
14 	if (!tramp)
15 		return;
16 
17 	mutex_lock(&text_mutex);
18 
19 	if (func && !is_short) {
20 		err = patch_ulong(tramp + PPC_SCT_DATA, target);
21 		if (err)
22 			goto out;
23 	}
24 
25 	if (!func)
26 		err = patch_instruction(tramp, ppc_inst(PPC_RAW_BLR()));
27 	else if (is_short)
28 		err = patch_branch(tramp, target, 0);
29 	else
30 		err = patch_instruction(tramp, ppc_inst(PPC_RAW_NOP()));
31 out:
32 	mutex_unlock(&text_mutex);
33 
34 	if (err)
35 		panic("%s: patching failed %pS at %pS\n", __func__, func, tramp);
36 }
37 EXPORT_SYMBOL_GPL(arch_static_call_transform);
38