Hello, world!

10 files changed, 215 insertions, 29 deletions

diff --git a/arch/arm/Makefile b/arch/arm/Makefile
index 7c74a409..84214f0a 100644
--- a/arch/arm/Makefile
+++ b/arch/arm/Makefile
@@ -1,6 +1,7 @@
 KCONFIG_DEFCONFIG := qemu_virt_defconfig
 
 XBUILD_CFLAGS += -mcpu=cortex-a15
+XBUILD_CFLAGS += -fdelete-null-pointer-checks
 
 x15_SOURCES-y += \
         arch/arm/machine/boot_asm.S \
@@ -8,4 +9,5 @@ x15_SOURCES-y += \
         arch/arm/machine/cpu.c \
         arch/arm/machine/pmap.c \
         arch/arm/machine/strace.c \
+        arch/arm/machine/tcb_asm.S \
         arch/arm/machine/tcb.c
diff --git a/arch/arm/machine/asm.h b/arch/arm/machine/asm.h
new file mode 100644
index 00000000..6474b225
--- /dev/null
+++ b/arch/arm/machine/asm.h
@@ -0,0 +1,42 @@
+/*
+ * Copyright (c) 2011, 2012 Richard Braun.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef _X86_ASM_H
+#define _X86_ASM_H
+
+#ifndef __ASSEMBLER__
+#warning "asm.h included from a C file"
+#endif /* __ASSEMBLER__ */
+
+#include <machine/cpu.h>
+
+#define ASM_FUNC(x)     \
+.align CPU_TEXT_SHIFT;  \
+.global x;              \
+.type x, STT_FUNC;      \
+x
+
+#define ASM_DATA(x)     \
+.align CPU_DATA_SHIFT;  \
+.global x;              \
+.type x, STT_OBJECT;    \
+x
+
+#define ASM_END(x) \
+.size x, . - x
+
+#endif /* _X86_ASM_H */
diff --git a/arch/arm/machine/boot.c b/arch/arm/machine/boot.c
index 121ad92a..eb054f66 100644
--- a/arch/arm/machine/boot.c
+++ b/arch/arm/machine/boot.c
@@ -15,8 +15,41 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
+#include <stdalign.h>
+#include <stddef.h>
+#include <stdint.h>
+
 #include <kern/init.h>
 #include <machine/boot.h>
+#include <machine/cpu.h>
+#include <machine/pmap.h>
+#include <vm/vm_kmem.h>
+
+alignas(CPU_DATA_ALIGN) char boot_stack[BOOT_STACK_SIZE] __bootdata;
+
+static char boot_hello_msg[] __bootdata = "Hello, world!\r\n";
+
+static void __boot
+boot_hello_world(void)
+{
+    volatile unsigned long *uart_data_reg = (volatile unsigned long *)0x9000000;
+    const char *s = boot_hello_msg;
+
+    while (*s != '\0') {
+        *uart_data_reg = *s;
+        s++;
+    }
+}
+
+void boot_setup_paging(void);
+
+void __boot
+boot_setup_paging(void)
+{
+    boot_hello_world();
+
+    for (;;);
+}
 
 void __init
 boot_log_info(void)
diff --git a/arch/arm/machine/boot.h b/arch/arm/machine/boot.h
index 6459e80b..0181f7a0 100644
--- a/arch/arm/machine/boot.h
+++ b/arch/arm/machine/boot.h
@@ -19,16 +19,33 @@
 #define _ARM_BOOT_H
 
 #include <kern/macros.h>
+#include <machine/page.h>
 #include <machine/pmap.h>
 
-#define BOOT_OFFSET DECL_CONST(0x0, UL)
+/*
+ * Size of the stack used when booting a processor.
+ */
+#define BOOT_STACK_SIZE PAGE_SIZE
+
+#define BOOT_LOAD_SECTION .boot.load
+#define BOOT_TEXT_SECTION .boot.text
+#define BOOT_DATA_SECTION .boot.data
 
-#define BOOT_VTOP(addr) ((addr) - PMAP_KERNEL_OFFSET)
+#define BOOT_RAM_START      0x40000000 /* XXX Specific to the Qemu virtual machine */
+#define BOOT_KERNEL_OFFSET  (PMAP_START_KERNEL_ADDRESS - BOOT_RAM_START)
+
+#define BOOT_RTOL(addr) ((addr) - BOOT_RAM_START)
+#define BOOT_VTOL(addr) ((addr) - PMAP_START_KERNEL_ADDRESS)
+
+#define BOOT_VTOP(addr) ((addr) - BOOT_RAM_START)
 
 #ifndef __ASSEMBLER__
 
 #include <kern/init.h>
 
+#define __boot     __section(QUOTE(BOOT_TEXT_SECTION))
+#define __bootdata __section(QUOTE(BOOT_DATA_SECTION)) __attribute__((used))
+
 /*
  * Log kernel version and other architecture-specific information.
  */
diff --git a/arch/arm/machine/boot_asm.S b/arch/arm/machine/boot_asm.S
index ccf3eb05..fedb63bb 100644
--- a/arch/arm/machine/boot_asm.S
+++ b/arch/arm/machine/boot_asm.S
@@ -15,11 +15,64 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
-.section .boot.hdr, "awx"
+#include <machine/asm.h>
+#include <machine/boot.h>
+#include <machine/pmap.h>
 
-.long _start
+.section BOOT_LOAD_SECTION, "awx"
 
-.global _start
-_start:
- mov %r0, #0x12
- b .
+ASM_DATA(boot_exception_table):
+ .long _start   /* Reset */
+ .long 0        /* Undefined instruction */
+ .long 0        /* Software interrupt */
+ .long 0        /* Prefetch abort */
+ .long 0        /* Data abort */
+ .long 0        /* IRQ */
+ .long 0        /* FIQ */
+ASM_END(boot_exception_table)
+
+ASM_FUNC(_start):
+ /*
+  * Assume the code runs from flash. For the sake of simplicity, make
+  * the kernel run from RAM. This requires relocating it, and since the
+  * RAM size isn't known, we can't use it for a stack. As a result,
+  * perform the relocation in assembly without using a stack.
+  */
+ ldr %r5, =(BOOT_RAM_START)             /* Load RAM address in %r5 */
+ mov %r6, #0                            /* Load kernel address in %r6 */
+ ldr %r0, boot_kernel_end               /* Load kernel end virtual address
+                                           in %r0 */
+ ldr %r1, =(PMAP_START_KERNEL_ADDRESS)  /* Load kernel virtual address in %r1 */
+ sub %r7, %r0, %r1                      /* Compute kernel size in bytes */
+ lsr %r7, %r7, #2                       /* Compute kernel size in words */
+
+ sub %r5, %r5, #4                       /* Prepare for auto-increment */
+ sub %r6, %r6, #4
+
+1:
+ ldr %r0, [%r6, #4]!                    /* Load word with auto-increment */
+ str %r0, [%r5, #4]!                    /* Store word with auto-increment */
+ sub %r7, %r7, #4                       /* Account for the written word */
+ cmp %r7, #0                            /* Check the number of words left */
+ beq 1f                                 /* Break if copy complete */
+ b 1b                                   /* Continue otherwise */
+
+1:
+ /* TODO Invalidate all caches */
+
+ /* Set up the stack */
+ ldr %r13, boot_stack_addr
+ add %r13, %r13, #BOOT_STACK_SIZE
+
+ bl boot_setup_paging
+
+ /* Never reached */
+ nop
+
+ASM_END(_start)
+
+boot_kernel_end:
+ .long _end
+
+boot_stack_addr:
+ .long boot_stack
diff --git a/arch/arm/machine/cpu.h b/arch/arm/machine/cpu.h
index 80e11a05..d8b4c4d1 100644
--- a/arch/arm/machine/cpu.h
+++ b/arch/arm/machine/cpu.h
@@ -29,8 +29,23 @@
 
 /*
  * Data alignment, normally the word size.
+ *
+ * TODO Check.
+ */
+#define CPU_DATA_SHIFT 2
+#define CPU_DATA_ALIGN (1 << CPU_DATA_SHIFT)
+
+/*
+ * Function alignment.
+ *
+ * Aligning functions improves instruction fetching.
+ *
+ * Used for assembly functions only.
+ *
+ * XXX Use this value until processor selection is available.
  */
-#define CPU_DATA_ALIGN (LONG_BIT / 8)
+#define CPU_TEXT_SHIFT 4
+#define CPU_TEXT_ALIGN (1 << CPU_TEXT_SHIFT)
 
 #ifndef __ASSEMBLER__
 
diff --git a/arch/arm/machine/pmap.h b/arch/arm/machine/pmap.h
index bae0c060..ecb3bf16 100644
--- a/arch/arm/machine/pmap.h
+++ b/arch/arm/machine/pmap.h
@@ -29,8 +29,6 @@
 #define PMAP_START_DIRECTMAP_ADDRESS    PMAP_END_ADDRESS
 #define PMAP_END_DIRECTMAP_ADDRESS      DECL_CONST(0xf8000000, UL)
 
-#define PMAP_KERNEL_OFFSET              PMAP_START_DIRECTMAP_ADDRESS
-
 #define PMAP_START_KMEM_ADDRESS         PMAP_END_DIRECTMAP_ADDRESS
 #define PMAP_END_KMEM_ADDRESS           PMAP_END_KERNEL_ADDRESS
 
diff --git a/arch/arm/machine/tcb_asm.S b/arch/arm/machine/tcb_asm.S
new file mode 100644
index 00000000..f58f429e
--- /dev/null
+++ b/arch/arm/machine/tcb_asm.S
@@ -0,0 +1,21 @@
+/*
+ * Copyright (c) 2017 Richard Braun.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <machine/asm.h>
+
+ASM_FUNC(tcb_load):
+ASM_END(tcb_load)
diff --git a/arch/arm/x15.lds.S b/arch/arm/x15.lds.S
index a5c6cd3b..d867de29 100644
--- a/arch/arm/x15.lds.S
+++ b/arch/arm/x15.lds.S
@@ -7,11 +7,11 @@ ENTRY(_start)
 #include <machine/boot.h>
 #include <machine/cpu.h>
 #include <machine/page.h>
-#include <machine/pmap.h>
 
 PHDRS
 {
     /* Flags are actually similar to classic Unix permissions */
+    load    PT_LOAD FLAGS(7);
     boot    PT_LOAD FLAGS(7);
     init    PT_LOAD FLAGS(7);
     percpu  PT_LOAD FLAGS(6);
@@ -22,22 +22,27 @@ PHDRS
 
 SECTIONS
 {
-    . = BOOT_OFFSET;
+    . = 0;
+
+    .boot.load : {
+        *(BOOT_LOAD_SECTION)
+    } : load
+
+    . += BOOT_RAM_START;
     _boot = .;
 
-    .boot ALIGN(PAGE_SIZE) : {
-        *(.boot.hdr)
-        *(.boot.text)
-        *(.boot.data)
+    .boot ALIGN(PAGE_SIZE) : AT(BOOT_RTOL(ADDR(.boot))) {
+        *(BOOT_TEXT_SECTION)
+        *(BOOT_DATA_SECTION)
     } : boot
 
     . = ALIGN(PAGE_SIZE);
     _boot_end = .;
 
-    . += PMAP_KERNEL_OFFSET;
+    . += (PMAP_START_KERNEL_ADDRESS - BOOT_RAM_START);
     _init = .;
 
-    .init ALIGN(PAGE_SIZE) : AT(BOOT_VTOP(ADDR(.init))) {
+    .init ALIGN(PAGE_SIZE) : AT(BOOT_VTOL(ADDR(.init))) {
         *(.init.text)
         *(.init.data)
 
@@ -52,7 +57,7 @@ SECTIONS
     _init_end = .;
     _percpu = .;
 
-    .percpu 0 : AT(BOOT_VTOP(_percpu)) {
+    .percpu 0 : AT(BOOT_VTOL(_percpu)) {
         *(.percpu)
     } : percpu
 
@@ -61,32 +66,32 @@ SECTIONS
     _percpu_end = .;
     _text = .;
 
-    .text ALIGN(PAGE_SIZE) : AT(BOOT_VTOP(ADDR(.text))) {
+    .text ALIGN(PAGE_SIZE) : AT(BOOT_VTOL(ADDR(.text))) {
         *(.text)
     } : text
 
     . = ALIGN(PAGE_SIZE);
     _rodata = .;
 
-    .rodata ALIGN(PAGE_SIZE) : AT(BOOT_VTOP(ADDR(.rodata))) {
+    .rodata ALIGN(PAGE_SIZE) : AT(BOOT_VTOL(ADDR(.rodata))) {
         *(.rodata)
     } : rodata
 
-    .notes ALIGN(CPU_DATA_ALIGN) : AT(BOOT_VTOP(ADDR(.notes))) {
+    .notes ALIGN(CPU_DATA_ALIGN) : AT(BOOT_VTOL(ADDR(.notes))) {
         *(.note.*)
     } : rodata
 
     . = ALIGN(PAGE_SIZE);
     _data = .;
 
-    .data ALIGN(PAGE_SIZE) : AT(BOOT_VTOP(ADDR(.data))) {
+    .data ALIGN(PAGE_SIZE) : AT(BOOT_VTOL(ADDR(.data))) {
         . = ALIGN(CPU_L1_SIZE);
         *(.data.read_mostly)
         . = ALIGN(CPU_L1_SIZE);
         *(.data)
     } : data
 
-    .bss ALIGN(CPU_DATA_ALIGN) : AT(BOOT_VTOP(ADDR(.bss))) {
+    .bss ALIGN(CPU_DATA_ALIGN) : AT(BOOT_VTOL(ADDR(.bss))) {
         *(.bss)
     } : data
 
diff --git a/arch/x86/machine/asm.h b/arch/x86/machine/asm.h
index 204d6fed..754c8f2f 100644
--- a/arch/x86/machine/asm.h
+++ b/arch/x86/machine/asm.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2011, 2012 Richard Braun.
+ * Copyright (c) 2011-2012 Richard Braun.
  *
  * This program is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -15,8 +15,8 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
-#ifndef _X86_ASM_H
-#define _X86_ASM_H
+#ifndef _ARM_ASM_H
+#define _ARM_ASM_H
 
 #ifndef __ASSEMBLER__
 #warning "asm.h included from a C file"
@@ -39,4 +39,4 @@ x:
 #define ASM_END(x)  \
 .size x, . - x
 
-#endif /* _X86_ASM_H */
+#endif /* _ARM_ASM_H */