simplify linking of libkernel

3 files changed, 25 insertions, 57 deletions

diff --git a/Makefile b/Makefile
index 35cc48c..d782eda 100644
--- a/Makefile
+++ b/Makefile
@@ -5,8 +5,6 @@ ARM_OBJECTS=kernel.o paging.o demo_functionality.o PL0_test.o uart.o loader_stag
 
 EMBEDDABLE_OBJECTS=PL_0_test_embeddable.o loader_stage2_embeddable.o
 
-RENAME_FLAGS=--rename-section .data=.renamed_data --rename-section .rodata=.renamed_rodata --rename-section .text=.renamed_text --rename-section .bss=.renamed_bss
-
 all : kernel7.img
 
 %.o : %.c
@@ -21,13 +19,10 @@ all : kernel7.img
 %_embeddable.o : %.img
 	arm-none-eabi-objcopy -I binary -O elf32-littlearm -B arm --rename-section .data=.rodata $^ $@
 
-libkernel_renamed.o : libkernel.o
-	arm-none-eabi-objcopy $(RENAME_FLAGS) $^ $@
-
 PL_0_test.elf : PL0_test.o uart.o
 	arm-none-eabi-gcc -T PL0_test.ld -o $@ $(ELFFLAGS) $^
 
-kernel.elf : boot.o kernel.o uart.o PL_0_test_embeddable.o demo_functionality.o paging.o libkernel_renamed.o interrupt_vector.o interrupts.o
+kernel.elf : boot.o kernel.o uart.o PL_0_test_embeddable.o demo_functionality.o paging.o libkernel.o interrupt_vector.o interrupts.o
 	arm-none-eabi-gcc -T linker.ld -o $@ $(ELFFLAGS) $^
 
 loader.elf : boot.o loader_stage1.o loader_stage2.o uart.o
diff --git a/demo_functionality.c b/demo_functionality.c
index 19a5c38..aedab08 100644
--- a/demo_functionality.c
+++ b/demo_functionality.c
@@ -57,9 +57,9 @@ void demo_current_mode(void)
   ((short_section_descriptor_t volatile*) TRANSLATION_TABLE_BASE)
 
 extern char
-  __renamed_start,
-  __renamed_end,
-  __renamed_size;
+  __libkernel_start,
+  __libkernel_end,
+  __libkernel_size;
 
 void demo_setup_libkernel(void) {
   short_section_descriptor_t volatile *libkernel_section_entry =
@@ -82,9 +82,9 @@ void demo_setup_libkernel(void) {
       "isb" :: "r" (0) : "memory");
   
   // copy libkernel code to libkernel section
-  for (size_t i = 0; i < (size_t) &__renamed_size; i++)
+  for (size_t i = 0; i < (size_t) &__libkernel_size; i++)
     ((volatile char*) LIBKERNEL_SECTION_START)[i] =
-      (&__renamed_start)[i];  
+      (&__libkernel_start)[i];
 }
 
 extern char
@@ -146,7 +146,7 @@ void demo_setup_PL0(void)
 void demo_go_unprivileged(void)
 {
   size_t call_unprivileged_offset =
-    (size_t) &call_unprivileged - (size_t) &__renamed_start;
+    (size_t) &call_unprivileged - (size_t) &__libkernel_start;
 
   void *call_unprivileged_new_location =
     (void*) (LIBKERNEL_SECTION_START + call_unprivileged_offset);
diff --git a/linker.ld b/linker.ld
index 01eda35..387e7c7 100644
--- a/linker.ld
+++ b/linker.ld
@@ -1,18 +1,21 @@
-ENTRY(_start)
+ENTRY(_start) /* defined in boot.S */
  
 SECTIONS
 {
-    /* Starts at LOADER_ADDR, which is 0x8000 - that's where RPis in */
-    /* 32-bit mode load kernel at. */
+    /* Starts at  0x8000 - that's where RPis in 32-bit mode load kernel at. */
     /* My experiments do, however, show, that qemu emulating RPi2 */
     /* loads the kernel at 0x10000! (took some pain to find out). */
-    /* Since we're using a bootloader now, we can compile the kernel */
-    /* for 0x8000 and bootloader will load it properly (although it */
-    /* itself still has to be compiled for 0x10000) */
-    /* rpi-open-firmware, ont he other hand, loads kernel at 0x2000000 */
-    /* This issue is also to be avoided by the use of bootloader */
+    /* rpi-open-firmware, on the other hand, loads kernel at 0x2000000! */
+    /* This is not really a problem, since: */
+    /*   1. We can use out bootloader to load the kernel at 0x8000 */
+    /*   2. We compile kernel with -fPIC, so it should be able to work with */
+    /*      any load addr.
+    /*   3. In qemu, we can load kernel.elf instead of raw binary */
+    /*      (qemu will do the loading then) */
+
     . = 0x8000;
-    /* For AArch64, use . = 0x80000; Unless this too is wrong in qemu… */
+
+    /* For AArch64, use . = 0x80000 */
     
     __start = .;
     __text_start = .;
@@ -51,44 +54,14 @@ SECTIONS
     __bss_size = __bss_end - __bss_start;
 
 
-
-    /* Here come the definitions for renamed sections */
-    __renamed_start = .;
-    __renamed_text_start = .;
-    .renamed_text :
-    {
-        *(.renamed_text)
-    }
-    . = ALIGN(4096); /* align to page size */
-    __renamed_text_end = .;
- 
-    __renamed_rodata_start = .;
-    .renamed_rodata :
-    {
-        *(.renamed_rodata)
-    }
-    . = ALIGN(4096); /* align to page size */
-    __renamed_rodata_end = .;
- 
-    __renamed_data_start = .;
-    .renamed_data :
-    {
-        *(.renamed_data)
-    }
-    . = ALIGN(4096); /* align to page size */
-    __renamed_data_end = .;
- 
-    __renamed_bss_start = .;
-    .renamed_bss :
+    /* libkernel */
+    .libkernel :
     {
-        renamed_bss = .;
-        *(.renamed_bss)
+	__libkernel_start = .;
+	libkernel.o
+	__libkernel_end = .;
     }
-    . = ALIGN(4096); /* align to page size */
-    __renamed_bss_end = .;
-    __renamed_bss_size = __renamed_bss_end - __renamed_bss_start;
-    __renamed_end = .;
-    __renamed_size = __renamed_end - __renamed_start;
+    __libkernel_size = __libkernel_end - __libkernel_start;
 
 
     . = ALIGN(4096); /* align to page size */