tools/testing/selftests/powerpc/include/basic_asm.h

   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 */