include/asm-generic/pie.lds.h

   1 /*
   2  * Helper macros to support writing architecture specific
   3  * pie linker scripts.
   4  *
   5  * A minimal linker scripts has following content:
   6  * [This is a sample, architectures may have special requiriements]
   7  *
   8  * OUTPUT_FORMAT(...)
   9  * OUTPUT_ARCH(...)
  10  * SECTIONS
  11  * {
  12  *      . = 0x0;
  13  *
  14  *      PIE_COMMON_START
  15  *      .text {
  16  *              PIE_TEXT_TEXT
  17  *      }
  18  *      PIE_COMMON_END
  19  *
  20  *      PIE_OVERLAY_START
  21  *      OVERLAY : NOCROSSREFS {
  22  *              PIE_OVERLAY_SECTION(am33xx)
  23  *              PIE_OVERLAY_SECTION(am347x)
  24  *              [...]
  25  *      }
  26  *      PIE_OVERLAY_END
  27  *
  28  *      PIE_DISCARDS            // must be the last
  29  * }
  30  */
  31
  32 #include <asm-generic/vmlinux.lds.h>
  33
  34 #define PIE_COMMON_START                                                \
  35         __pie_common_start : {                                          \
  36                 VMLINUX_SYMBOL(__pie_common_start) = .;                 \
  37         }
  38
  39 #define PIE_COMMON_END                                                  \
  40         __pie_common_end : {                                            \
  41                 VMLINUX_SYMBOL(__pie_common_end) = .;                   \
  42         }
  43
  44 #define PIE_OVERLAY_START                                               \
  45         __pie_overlay_start : {                                         \
  46                 VMLINUX_SYMBOL(__pie_overlay_start) = .;                \
  47         }
  48
  49 #define PIE_OVERLAY_END                                                 \
  50         __pie_overlay_end : {                                           \
  51                 VMLINUX_SYMBOL(__pie_overlay_end) = .;                  \
  52         }
  53
  54 #define PIE_TEXT_TEXT                                                   \
  55         KEEP(*(.pie.text))
  56
  57 #define PIE_OVERLAY_SECTION(name)                                       \
  58         .pie.##name {                                                   \
  59                 KEEP(*(.pie.##name##.*))                                \
  60                 VMLINUX_SYMBOL(__pie_##name##_start) =                  \
  61                                 LOADADDR(.pie.##name##);                \
  62                 VMLINUX_SYMBOL(__pie_##name##_end) =                    \
  63                                 LOADADDR(.pie.##name##) +               \
  64                                 SIZEOF(.pie.##name##);                  \
  65         }                                                               \
  66         .rel.##name {                                                   \
  67                 KEEP(*(.rel.pie.##name##.*))                            \
  68                 VMLINUX_SYMBOL(__pie_rel_##name##_start) =              \
  69                                 LOADADDR(.rel.##name##);                \
  70                 VMLINUX_SYMBOL(__pie_rel_##name##_end) =                \
  71                                 LOADADDR(.rel.##name##) +               \
  72                                 SIZEOF(.rel.##name##);                  \
  73         }
  74
  75 #define PIE_DISCARDS                                                    \
  76         /DISCARD/ : {                                                   \
  77         *(.dynsym)                                                      \
  78         *(.dynstr*)                                                     \
  79         *(.dynamic*)                                                    \
  80         *(.plt*)                                                        \
  81         *(.interp*)                                                     \
  82         *(.gnu*)                                                        \
  83         *(.hash)                                                        \
  84         *(.comment)                                                     \
  85         *(.bss*)                                                        \
  86         *(.data)                                                        \
  87         *(.discard)                                                     \
  88         *(.discard.*)                                                   \
  89         }
  90