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-rw-r--r--Makefile7
-rw-r--r--demo_functionality.c12
-rw-r--r--linker.ld63
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 */