Initial import

.clang-format

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+BasedOnStyle: Chromium
+Language: Cpp
+MaxEmptyLinesToKeep: 3
+IndentCaseLabels: false
+AllowShortIfStatementsOnASingleLine: false
+AllowShortCaseLabelsOnASingleLine: false
+AllowShortLoopsOnASingleLine: false
+DerivePointerAlignment: false
+PointerAlignment: Right
+SpaceAfterCStyleCast: true
+TabWidth: 4
+UseTab: Never
+IndentWidth: 4
+BreakBeforeBraces: Linux
+AccessModifierOffset: -4

Makefile

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+include Makefile.opt
+include Makefile.inc
+
+NAME = piko
+
+# select QEMU when the target is unspecified
+TARGET ?= stm32f429
+CMSIS = ../cmsis
+
+# The platform Makefile contains hw details and flags
+include target/$(TARGET)/Makefile
+
+# warning: return type of 'main' is not 'int' [-Wmain]
+CFLAGS += -Iinclude -Iinclude/libc -I. -I$(CMSIS)/arm -I$(CMSIS)/$(TARGET) -I$(CMSIS)/$(TARGET)/hal \
+	-Iinclude/kernel -D_POSIX_THREADS=1 -D_POSIX_TIMERS=1 -D_POSIX_REALTIME_SIGNALS=1 \
+	-Wno-main -DCONFIG_KERNEL_STACK_CHECKING -fdiagnostics-color \
+	-ffunction-sections -fdata-sections -Os -ggdb
+
+LDFLAGS += -nostartfiles -specs=nano.specs \
+	-Wl,-Map=$(NAME).map -Wl,-Tpiko.lds -Wl,--gc-sections
+
+# arch-specific
+SSRC += arch/v7m-head.S arch/v7m-entry.S arch/v7m-svcall.S
+CSRC += arch/v7m-faults.c
+
+LIBPIKO_CSRC = $(wildcard libc/*.c)
+LIBPIKO_SSRC = $(wildcard libc/*.S) $(wildcard libc/piko/*.S)
+
+SSRC += $(LIBPIKO_SSRC)
+
+CSRC += kernel/syscall.c
+CSRC += $(wildcard kernel/*.c)		\
+	$(wildcard kernel/fs/*.c)	\
+	$(wildcard kernel/mm/*.c)	\
+	$(wildcard drivers/char/*.c)	\
+	$(wildcard drivers/mtd/*.c)	\
+	$(wildcard drivers/timer/timercore.c) \
+	$(wildcard drivers/serial/serial*.c) \
+	$(wildcard user/*.c)		\
+	libc/piko/stubs.c		\
+	libc/piko/mman.c		\
+	$(LIBPIKO_CSRC)			\
+
+OBJS += $(SSRC:.S=.o) $(CSRC:.c=.o)
+OBJS := $(sort $(OBJS))
+
+.PHONY: all check clean distclean
+
+all: $(CMSIS)/$(TARGET) $(NAME).lds $(NAME).hex $(NAME).bin
+
+prebuild: $(CMSIS)/$(TARGET)
+
+$(NAME).elf: $(OBJS) kernel/fs/version.o
+	$(VECHO) "LD\t$@"
+	$(Q)$(CC) $(LDFLAGS) -o $@ $^
+
+%.o: %.c
+	$(VECHO) "CC\t$@"
+	$(Q)$(CC) -o $@ $(CFLAGS) -c -W -Wall -std=c11 -D__KERNEL__ $<
+
+%.o: %.S
+	$(VECHO) "AS\t$@"
+	$(Q)$(CC) -o $@ $(CFLAGS) -c $<
+
+%.lds: %.lds.S
+	$(VECHO) "HOSTCC\t$@"
+	$(Q)$(HOSTCC) -E -P -Iinclude -DROMSZ=$(ROMSZ) -DRAMSZ=$(RAMSZ) -o $@ $<
+
+include/cmsis/arm/core_cm4.h:
+	git submodule init
+	git submodule update
+
+kernel/syscall.c: include/kernel/syscalls.h
+	$(VECHO) "GEN\t$@"
+	$(Q)python scripts/gen-syscalls.py --source > $@
+
+include/kernel/syscalls.h:
+	$(VECHO) "GEN\t$@"
+	$(Q)python scripts/gen-syscalls.py --header > $@
+
+kernel/fs/version:
+	$(VECHO) "GEN\t$@"
+	$(Q)python3 scripts/gen-proc-version.py --cc-version    \
+	--user $(shell whoami) --host $(shell hostname)		\
+	-a $(ARCH) -c $(CPU) -n 'Piko' > $@
+
+kernel/fs/version.o: kernel/fs/version
+	$(VECHO) "OBJCOPY\t$@"
+	$(Q)$(OBJCOPY) -I binary -O elf32-littlearm -B arm		\
+	--rename-section .data=.rodata					\
+        --redefine-sym _binary_$(subst /,_,$<)_start=_version_ptr	\
+        --redefine-sym _binary_$(subst /,_,$<)_size=_version_len	\
+	$< $@
+
+%.hex: %.elf
+	$(VECHO) "OBJCOPY\t$@"
+	$(Q)$(OBJCOPY) -O ihex $< $@
+
+%.bin: %.elf
+	$(VECHO) "OBJCOPY\t$@"
+	$(Q)$(OBJCOPY) -Obinary $< $@
+
+check:
+	python3 tests/runner.py
+
+clean:
+	find . -name "*.o" -type f -delete
+	find $(CMSIS) -name "*.o" -type f -delete
+	rm -f $(NAME).map $(NAME).lds
+	rm -f $(NAME).elf $(NAME).hex
+	rm -f $(NAME).bin
+
+distclean: clean
+	rm -f kernel/syscall.c include/kernel/syscalls.h kernel/fs/version
+	rm -rf $(CMSIS)
+
+astyle:
+	astyle --style=linux --indent=tab --indent-switches --suffix=none --recursive *.c *.h
+
+# platform Makefile.rules contains flashing and running rules
+include target/$(TARGET)/Makefile.rules

Makefile.inc

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+CROSS   = arm-none-eabi-
+CC      = $(CROSS)gcc
+AS      = $(CROSS)as
+AR      = $(CROSS)ar
+OBJCOPY = $(CROSS)objcopy
+GDB     = $(CROSS)gdb
+HOSTCC  = gcc
+
+CFLAGS  += -mthumb -mcpu=$(CPU)
+LDFLAGS += -mthumb -march=$(ARCH)

Makefile.opt

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+# Control the build verbosity
+ifeq ("$(VERBOSE)","1")
+  Q :=
+  VECHO = @true
+else
+  Q := @
+  VECHO = @echo
+endif

arch/v7m-entry.S

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+#include <kernel/linkage.h>
+
+	.syntax unified
+	.thumb
+
+	@ do the thread-context switch
+	@
+	@ r0: struct thread_info *next
+	@ r1: struct thread_info *prev (i.e. the current thread)
+	@ (r1), r2, r3, r12: scratch registers
+ENTRY(switch_to)
+	/* save previous thread context */
+	push	{r4-r12, lr}
+	mov	r2, sp
+	mrs	r3, psp
+	stm	r1!, {r2, r3}
+
+ENTRY(thread_restore)
+	/* restore next task context */
+	ldm	r0!, {r1-r3}
+	mov	sp, r1
+	msr	psp, r2
+	msr	control, r3		@ write to SPSEL is ignored in Handler_Mode
+	pop	{r4-r12, pc}
+ENDPROC(thread_restore)
+ENDPROC(switch_to)
+
+	.macro	emulate_iret
+	ldrd	r0, r1, [sp, #24]	/* r0 = ret_addr, r1 = xpsr */
+	orr	r0, #1
+	str	r0, [sp, #24]
+	msr	apsr_nzcvq, r1		/* restore flags */
+	pop	{r0-r3, r12, lr}
+	ldr	pc, [sp], #8		/* return into user thread */
+	.endm
+
+ENTRY(return_from_sigaction)
+	add	sp, #12			/* reclaim siginfo_t storage */
+	emulate_iret
+END(return_from_sigaction)
+
+ENTRY(return_from_sighandler)
+	emulate_iret
+END(return_from_sighandler)
+
+	.set MC_SP, 0
+	.set MC_LR, 4
+	.set MC_GPRS, 8
+	.set MC_PC, 15*4
+	.set UC_MCONTEXT, 16
+	.set UC_LINK, 0
+
+	/* Swap context to a clean context (created from makecontext()):
+	 *   - save the non-scratch registers
+	 *   - just restore scratch registers (for arguments to entry function)
+	 *
+	 * Swap to a dirty context (inited with getcontext, or return to a
+	 * swapped context):
+	 *   - save the non-scratch registers
+	 *   - restore all registers
+	 */
+
+ENTRY(swapcontext)
+	/* save to oucp */
+	add	r0, #UC_MCONTEXT
+	str	sp, [r0, #MC_SP]
+	str	lr, [r0, #MC_LR]
+	add	r0, #MC_GPRS
+	stm	r0, {r0-r12, lr}
+
+	/* retore from ucp */
+	add	r1, #UC_MCONTEXT
+	ldr	sp, [r1, #MC_SP]
+	ldr	lr, [r1, #MC_LR]
+	add	r1, #MC_GPRS
+	ldm	r1, {r0-r12, pc}
+ENDPROC(swapcontext)
+
+ENTRY(return_from_makecontext)
+	/* retrieve the struct& from the top of the stack */
+	ldr	r0, [sp]
+
+	/* get the machine struct for the linked context */
+	ldr	r0, [r0, #UC_LINK]
+	add	r0, #UC_MCONTEXT
+
+	/* restore the link context */
+	ldr	sp, [r0, #MC_SP]
+	ldr	lr, [r0, #MC_LR]
+	add	r0, #MC_GPRS
+	//FIXME: return code - the r0 value that is restored from the stack should be 0
+	ldm	r0, {r0-r12, pc}
+ENDPROC(return_from_makecontext)
+
+	.macro	fault_handler f
+	push	{r4-r11}	@ save non-scratch registers at time of fault
+	mov	r0, sp
+	mov	r2, lr		@ lr contains EXC_RETURN, fault was taken in thread or interrupt?
+
+	@ We don't handle faults taken in interrupt handler at the moment.
+	@ Hence the scratch registers auto pushed to the stack by the CPU
+	@ on interrupt-entry have been pushed to PSP (MSP is only used by
+	@ interrupts handler).
+	mrs	r1, psp
+
+	b	\f
+	.endm	/* fault_handler */
+
+ENTRY(hardf)
+	fault_handler hardfault
+ENDPROC(hardf)
+
+ENTRY(memf)
+	fault_handler memmanage
+ENDPROC(memf)
+
+ENTRY(busf)
+	fault_handler busfault
+ENDPROC(busf)
+
+ENTRY(usgf)
+	fault_handler usagefault
+ENDPROC(usgf)
+
+ENTRY(__do_idle)
+	wfi
+	bx	lr
+ENDPROC(__do_idle)
+
+	/* void v7m_semihost_exit(int status); */
+ENTRY(v7m_semihost_exit)
+	tst	r0, r0
+	ite	eq
+	ldreq	r1, =0x20026    /* [a] */
+	movne	r1, #0
+	mov	r0, #0x18       /* [b] */
+	bkpt	#0xab
+0:	b	0b
+ENDPROC(v7m_semihost_exit)
+
+/* [a] https://lists.nongnu.org/archive/html/qemu-devel/2014-12/msg01575.html
+ *     ADP_Stopped_ApplicationExit is used for exit(0), anything else is
+ *     implemented as exit(1). */
+
+/* [b] http://git.qemu.org/?p=qemu.git;a=blob_plain;f=target-arm/arm-semi.c;hb=HEAD
+ *     List of supported semihosting calls in Qemu. */

arch/v7m-faults.c

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+#include <kernel/faults.h>
+#include <kernel/thread.h>
+
+#include "kernel.h"
+
+#define UFSR_DIVBYZERO (1 << 9)
+#define UFSR_UNALIGNED (1 << 8)
+#define UFSR_NOCP (1 << 3)
+#define UFSR_INVPC (1 << 2)
+#define UFSR_INVSTATE (1 << 1)
+#define UFSR_UNDEFINSTR 1
+
+void dump_frame(struct kernel_context_regs *noscratch,
+                struct thread_context_regs *scratch,
+                u32 exc_return)
+{
+	printk(" r0: %08x    r1: %08x    r2: %08x    r3: %08x\n",
+	       scratch->r0_r3__r12[0], scratch->r0_r3__r12[1],
+	       scratch->r0_r3__r12[2], scratch->r0_r3__r12[3]);
+	printk(" r4: %08x    r5: %08x    r6: %08x    r7: %08x\n",
+	       noscratch->r4_r12[0], noscratch->r4_r12[1], noscratch->r4_r12[2],
+	       noscratch->r4_r12[3]);
+	printk(" r8: %08x    r9: %08x   r10: %08x   r11: %08x\n",
+	       noscratch->r4_r12[4], noscratch->r4_r12[5], noscratch->r4_r12[6],
+	       noscratch->r4_r12[7]);
+	printk("r12: %08x    sp: %08x    lr: %08x    pc: %08x\n",
+	       scratch->r0_r3__r12[4], (u32) scratch, scratch->lr,
+	       scratch->ret_addr);
+	printk("\nEXC_RETURN: %08x\n", exc_return);
+}
+
+void usagefault(struct kernel_context_regs *noscratch,
+                struct thread_context_regs *scratch,
+                u32 exc_return)
+{
+	u32 ufsr = (*((volatile u32 *) 0xe000ed28)) >> 16;
+	const char *cause = NULL;
+
+	fault_enter("UsageFault");
+	dump_frame(noscratch, scratch, exc_return);
+	if (ufsr & UFSR_DIVBYZERO)
+		cause = "DIVBYZERO";
+	else if (ufsr & UFSR_UNALIGNED)
+		cause = "UNALIGNED";
+	else if (ufsr & UFSR_NOCP)
+		cause = "NOCP";
+	else if (ufsr & UFSR_INVPC)
+		cause = "INVPC";
+	else if (ufsr & UFSR_INVSTATE)
+		cause = "INVSTATE";
+	else if (ufsr & UFSR_UNDEFINSTR)
+		cause = "UNDEFINSTR";
+	if (cause)
+		printk("      ufsr: %08x  <%s>\n", ufsr, cause);
+	else
+		printk("      ufsr: %08x\n", ufsr);
+	fault_exit();
+}
+
+void busfault(struct kernel_context_regs *noscratch,
+              struct thread_context_regs *scratch,
+              u32 exc_return)
+{
+	fault_enter("BusFault");
+	dump_frame(noscratch, scratch, exc_return);
+	fault_exit();
+}
+
+void memmanage(struct kernel_context_regs *noscratch,
+               struct thread_context_regs *scratch,
+               u32 exc_return)
+{
+	fault_enter("MemManage");
+	dump_frame(noscratch, scratch, exc_return);
+	fault_exit();
+}