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
arch_static_call_transform(void * site,void * tramp,void * func,bool tail)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