xref: /linux/arch/arm64/kernel/static_call.c (revision 995832b2cebe6969d1b42635db698803ee31294d)
1 // SPDX-License-Identifier: GPL-2.0
2 #include <linux/static_call.h>
3 #include <linux/memory.h>
4 #include <asm/text-patching.h>
5 #include <asm/insn.h>
6 
7 void arch_static_call_transform(void *site, void *tramp, void *func, bool tail)
8 {
9 	u64 literal;
10 	int ret;
11 
12 	if (!func)
13 		func = __static_call_return0;
14 
15 	/* decode the instructions to discover the literal address */
16 	literal = ALIGN_DOWN((u64)tramp + 4, SZ_4K) +
17 		  aarch64_insn_adrp_get_offset(le32_to_cpup(tramp + 4)) +
18 		  8 * aarch64_insn_decode_immediate(AARCH64_INSN_IMM_12,
19 						    le32_to_cpup(tramp + 8));
20 
21 	ret = aarch64_insn_write_literal_u64((void *)literal, (u64)func);
22 	WARN_ON_ONCE(ret);
23 }
24 EXPORT_SYMBOL_GPL(arch_static_call_transform);
25