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