linkage.h

 1/* SPDX-License-Identifier: GPL-2.0 */
 2#ifndef __ASM_LINKAGE_H
 3#define __ASM_LINKAGE_H
 4
 5#define __ALIGN		.align 2
 6#define __ALIGN_STR	__stringify(__ALIGN)
 7
 8#define SYM_FUNC_START(name)				\
 9	SYM_START(name, SYM_L_GLOBAL, SYM_A_ALIGN)	\
10	.cfi_startproc;
11
12#define SYM_FUNC_START_NOALIGN(name)			\
13	SYM_START(name, SYM_L_GLOBAL, SYM_A_NONE)	\
14	.cfi_startproc;
15
16#define SYM_FUNC_START_LOCAL(name)			\
17	SYM_START(name, SYM_L_LOCAL, SYM_A_ALIGN)	\
18	.cfi_startproc;
19
20#define SYM_FUNC_START_LOCAL_NOALIGN(name)		\
21	SYM_START(name, SYM_L_LOCAL, SYM_A_NONE)	\
22	.cfi_startproc;
23
24#define SYM_FUNC_START_WEAK(name)			\
25	SYM_START(name, SYM_L_WEAK, SYM_A_ALIGN)	\
26	.cfi_startproc;
27
28#define SYM_FUNC_START_WEAK_NOALIGN(name)		\
29	SYM_START(name, SYM_L_WEAK, SYM_A_NONE)		\
30	.cfi_startproc;
31
32#define SYM_FUNC_END(name)				\
33	.cfi_endproc;					\
34	SYM_END(name, SYM_T_FUNC)
35
36#define SYM_CODE_START(name)				\
37	SYM_START(name, SYM_L_GLOBAL, SYM_A_ALIGN)	\
38	.cfi_startproc;
39
40#define SYM_CODE_END(name)				\
41	.cfi_endproc;					\
42	SYM_END(name, SYM_T_NONE)
43
44/*
45 * This is for the signal handler trampoline, which is used as the return
46 * address of the signal handlers in userspace instead of called normally.
47 * The long standing libgcc bug https://gcc.gnu.org/PR124050 requires a
48 * nop between .cfi_startproc and the actual address of the trampoline, so
49 * we cannot simply use SYM_FUNC_START.
50 *
51 * This wrapper also contains all the .cfi_* directives for recovering
52 * the content of the GPRs and the "return address" (where the rt_sigreturn
53 * syscall will jump to), assuming there is a struct rt_sigframe (where
54 * a struct sigcontext containing those information we need to recover) at
55 * $sp.  The "DWARF for the LoongArch(TM) Architecture" manual states
56 * column 0 is for $zero, but it does not make too much sense to
57 * save/restore the hardware zero register.  Repurpose this column here
58 * for the return address (here it's not the content of $ra we cannot use
59 * the default column 3).
60 */
61#define SYM_SIGFUNC_START(name)				\
62	.cfi_startproc;					\
63	.cfi_signal_frame;				\
64	.cfi_def_cfa 3, RT_SIGFRAME_SC;			\
65	.cfi_return_column 0;				\
66	.cfi_offset 0, SC_PC;				\
67							\
68	.irp num, 1,  2,  3,  4,  5,  6,  7,  8, 	\
69		  9,  10, 11, 12, 13, 14, 15, 16,	\
70		  17, 18, 19, 20, 21, 22, 23, 24,	\
71		  25, 26, 27, 28, 29, 30, 31;		\
72	.cfi_offset \num, SC_REGS + \num * SZREG;	\
73	.endr;						\
74							\
75	nop;						\
76	SYM_START(name, SYM_L_GLOBAL, SYM_A_ALIGN)
77
78#define SYM_SIGFUNC_END(name) SYM_FUNC_END(name)
79
80#endif