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f50b45626e
Implement inline static calls:
- Put a 'bl' to the destination function ('b' if tail call)
- Put a 'nop' when the destination function is NULL ('blr' if tail call)
- Put a 'li r3,0' when the destination is the RET0 function and not
a tail call.
If the destination is too far (over the 32Mb limit), go via the
trampoline.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Madhavan Srinivasan <maddy@linux.ibm.com>
Link: https://patch.msgid.link/3dbd0b2ba577c942729235d0211d04a406653d81.1733245362.git.christophe.leroy@csgroup.eu
65 lines
1.7 KiB
C
65 lines
1.7 KiB
C
// SPDX-License-Identifier: GPL-2.0
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#include <linux/memory.h>
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#include <linux/static_call.h>
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#include <asm/text-patching.h>
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void arch_static_call_transform(void *site, void *tramp, void *func, bool tail)
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{
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int err;
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bool is_ret0 = (func == __static_call_return0);
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unsigned long _tramp = (unsigned long)tramp;
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unsigned long _func = (unsigned long)func;
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unsigned long _ret0 = _tramp + PPC_SCT_RET0;
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bool is_short = is_offset_in_branch_range((long)func - (long)(site ? : tramp));
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mutex_lock(&text_mutex);
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if (site && tail) {
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if (!func)
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err = patch_instruction(site, ppc_inst(PPC_RAW_BLR()));
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else if (is_ret0)
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err = patch_branch(site, _ret0, 0);
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else if (is_short)
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err = patch_branch(site, _func, 0);
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else if (tramp)
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err = patch_branch(site, _tramp, 0);
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else
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err = 0;
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} else if (site) {
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if (!func)
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err = patch_instruction(site, ppc_inst(PPC_RAW_NOP()));
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else if (is_ret0)
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err = patch_instruction(site, ppc_inst(PPC_RAW_LI(_R3, 0)));
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else if (is_short)
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err = patch_branch(site, _func, BRANCH_SET_LINK);
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else if (tramp)
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err = patch_branch(site, _tramp, BRANCH_SET_LINK);
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else
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err = 0;
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} else if (tramp) {
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if (func && !is_short) {
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err = patch_ulong(tramp + PPC_SCT_DATA, _func);
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if (err)
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goto out;
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}
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if (!func)
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err = patch_instruction(tramp, ppc_inst(PPC_RAW_BLR()));
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else if (is_ret0)
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err = patch_branch(tramp, _ret0, 0);
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else if (is_short)
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err = patch_branch(tramp, _func, 0);
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else
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err = patch_instruction(tramp, ppc_inst(PPC_RAW_NOP()));
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} else {
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err = 0;
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}
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out:
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mutex_unlock(&text_mutex);
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if (err)
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panic("%s: patching failed %pS at %pS\n", __func__, func, tramp);
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}
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EXPORT_SYMBOL_GPL(arch_static_call_transform);
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