ARM: vmlinux-xip.lds.S: fix multiple issues

The XIP linker script has several problems:

- PAGE_ALIGNED_DATA is missing and is likely to end up somewhere with
  the wrong LMA.

- BUG_TABLE definitely has the wrong LMA, it is not copied to RAM, and
  its VMA is unaccounted for and likely to clash with dynamic memory
  usage.

- TCM usage is similarly broken.

- PERCPU_SECTION is left in ROM despite being written to.

Let's use generic macros for those things and locate them appropriately.
Incidentally, those macros are usable with a LMA != VMA already by
properly defining LOAD_OFFSET.

TCM is not fixed here. It never worked in a XIP configuration anyway, so
that can wait until another round of cleanups.

Signed-off-by: Nicolas Pitre <nico@linaro.org>
Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Tested-by: Chris Brandt <Chris.Brandt@renesas.com>

diff --git a/arch/arm/kernel/vmlinux-xip.lds.S b/arch/arm/kernel/vmlinux-xip.lds.S
index 88e8db3..39b1fb4 100644 (file)
--- a/arch/arm/kernel/vmlinux-xip.lds.S
+++ b/arch/arm/kernel/vmlinux-xip.lds.S
@@ -179,7 +179,7 @@ SECTIONS
                *(.taglist.init)
                __tagtable_end = .;
        }
-       .init.data : {
+       .init.rodata : {
                INIT_SETUP(16)
                INIT_CALLS
                CON_INITCALL
@@ -187,48 +187,46 @@ SECTIONS
                INIT_RAM_FS
        }
 
-#ifdef CONFIG_SMP
-       PERCPU_SECTION(L1_CACHE_BYTES)
-#endif
-
        _exiprom = .;                   /* End of XIP ROM area */
-       __data_loc = ALIGN(4);          /* location in binary */
-       . = PAGE_OFFSET + TEXT_OFFSET;
-
-       .data : AT(__data_loc) {
-               _data = .;              /* address in memory */
-               _sdata = .;
 
-               /*
-                * first, the init task union, aligned
-                * to an 8192 byte boundary.
-                */
-               INIT_TASK_DATA(THREAD_SIZE)
+/*
+ * From this point, stuff is considered writable and will be copied to RAM
+ */
+       __data_loc = ALIGN(4);          /* location in file */
+       . = PAGE_OFFSET + TEXT_OFFSET;  /* location in memory */
+#undef LOAD_OFFSET
+#define LOAD_OFFSET (PAGE_OFFSET + TEXT_OFFSET - __data_loc)
+
+       . = ALIGN(THREAD_SIZE);
+       _sdata = .;
+       RW_DATA_SECTION(L1_CACHE_BYTES, PAGE_SIZE, THREAD_SIZE)
+       .data.ro_after_init : AT(ADDR(.data.ro_after_init) - LOAD_OFFSET) {
+               *(.data..ro_after_init)
+       }
+       _edata = .;
 
-               . = ALIGN(PAGE_SIZE);
-               __init_begin = .;
+       . = ALIGN(PAGE_SIZE);
+       __init_begin = .;
+       .init.data : AT(ADDR(.init.data) - LOAD_OFFSET) {
                INIT_DATA
+       }
+       .exit.data : AT(ADDR(.exit.data) - LOAD_OFFSET) {
                ARM_EXIT_KEEP(EXIT_DATA)
-               . = ALIGN(PAGE_SIZE);
-               __init_end = .;
-
-               *(.data..ro_after_init)
-
-               NOSAVE_DATA
-               CACHELINE_ALIGNED_DATA(L1_CACHE_BYTES)
-               READ_MOSTLY_DATA(L1_CACHE_BYTES)
-
-               /*
-                * and the usual data section
-                */
-               DATA_DATA
-               CONSTRUCTORS
-
-               _edata = .;
        }
-       _edata_loc = __data_loc + SIZEOF(.data);
+#ifdef CONFIG_SMP
+       PERCPU_SECTION(L1_CACHE_BYTES)
+#endif
+
+       /*
+        * End of copied data. We need a dummy section to get its LMA.
+        * Also located before final ALIGN() as trailing padding is not stored
+        * in the resulting binary file and useless to copy.
+        */
+       .data.endmark : AT(ADDR(.data.endmark) - LOAD_OFFSET) { }
+       _edata_loc = LOADADDR(.data.endmark);
 
-       BUG_TABLE
+       . = ALIGN(PAGE_SIZE);
+       __init_end = .;
 
 #ifdef CONFIG_HAVE_TCM
         /*