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