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

   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 */