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1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _SELFTESTS_POWERPC_BASIC_ASM_H
3 #define _SELFTESTS_POWERPC_BASIC_ASM_H
4 
5 #include <ppc-asm.h>
6 #include <asm/unistd.h>
7 
8 #define LOAD_REG_IMMEDIATE(reg, expr) \
9 	lis	reg, (expr)@highest;	\
10 	ori	reg, reg, (expr)@higher;	\
11 	rldicr	reg, reg, 32, 31;	\
12 	oris	reg, reg, (expr)@high;	\
13 	ori	reg, reg, (expr)@l;
14 
15 /*
16  * Note: These macros assume that variables being stored on the stack are
17  * doublewords, while this is usually the case it may not always be the
18  * case for each use case.
19  */
20 #if defined(_CALL_ELF) && _CALL_ELF == 2
21 #define STACK_FRAME_MIN_SIZE 32
22 #define STACK_FRAME_TOC_POS  24
23 #define __STACK_FRAME_PARAM(_param)  (32 + ((_param)*8))
24 #define __STACK_FRAME_LOCAL(_num_params, _var_num)  \
25 	((STACK_FRAME_PARAM(_num_params)) + ((_var_num)*8))
26 #else
27 #define STACK_FRAME_MIN_SIZE 112
28 #define STACK_FRAME_TOC_POS  40
29 #define __STACK_FRAME_PARAM(i)  (48 + ((i)*8))
30 
31 /*
32  * Caveat: if a function passed more than 8 doublewords, the caller will have
33  * made more space... which would render the 112 incorrect.
34  */
35 #define __STACK_FRAME_LOCAL(_num_params, _var_num)  \
36 	(112 + ((_var_num)*8))
37 #endif
38 
39 /* Parameter x saved to the stack */
40 #define STACK_FRAME_PARAM(var)    __STACK_FRAME_PARAM(var)
41 
42 /* Local variable x saved to the stack after x parameters */
43 #define STACK_FRAME_LOCAL(num_params, var)    \
44 	__STACK_FRAME_LOCAL(num_params, var)
45 #define STACK_FRAME_LR_POS   16
46 #define STACK_FRAME_CR_POS   8
47 
48 /*
49  * It is very important to note here that _extra is the extra amount of
50  * stack space needed. This space can be accessed using STACK_FRAME_PARAM()
51  * or STACK_FRAME_LOCAL() macros.
52  *
53  * r1 and r2 are not defined in ppc-asm.h (instead they are defined as sp
54  * and toc). Kernel programmers tend to prefer rX even for r1 and r2, hence
55  * %1 and %r2. r0 is defined in ppc-asm.h and therefore %r0 gets
56  * preprocessed incorrectly, hence r0.
57  */
58 #define PUSH_BASIC_STACK(_extra) \
59 	mflr	r0; \
60 	std	r0, STACK_FRAME_LR_POS(%r1); \
61 	stdu	%r1, -(_extra + STACK_FRAME_MIN_SIZE)(%r1); \
62 	mfcr	r0; \
63 	stw	r0, STACK_FRAME_CR_POS(%r1); \
64 	std	%r2, STACK_FRAME_TOC_POS(%r1);
65 
66 #define POP_BASIC_STACK(_extra) \
67 	ld	%r2, STACK_FRAME_TOC_POS(%r1); \
68 	lwz	r0, STACK_FRAME_CR_POS(%r1); \
69 	mtcr	r0; \
70 	addi	%r1, %r1, (_extra + STACK_FRAME_MIN_SIZE); \
71 	ld	r0, STACK_FRAME_LR_POS(%r1); \
72 	mtlr	r0;
73 
74 #endif /* _SELFTESTS_POWERPC_BASIC_ASM_H */
75