RM-2901: Added support for the ARMv7-M VFP Extension

arch/arm/Makefile

@@ -300,7 +300,12 @@ INSTALL_TARGETS	= zinstall uinstall install
 
 PHONY += bzImage $(BOOT_TARGETS) $(INSTALL_TARGETS)
 
+ifeq ($(CONFIG_KERNEL_COMPRESS_NONE),y)
+bootpImage uImage: Image
+else
 bootpImage uImage: zImage
+endif
+
 zImage: Image
 
 $(BOOT_TARGETS): vmlinux

arch/arm/boot/Makefile

@@ -63,8 +63,14 @@ $(obj)/Image: vmlinux FORCE
 $(obj)/compressed/vmlinux: $(obj)/Image FORCE
 	$(Q)$(MAKE) $(build)=$(obj)/compressed $@
 
+ifeq ($(CONFIG_KERNEL_COMPRESS_NONE),y)
+$(obj)/zImage: FORCE
+	@$(kecho) 'Kernel configured for no compression (CONFIG_COMPRESS_NONE=y)'
+	@false
+else
 $(obj)/zImage:	$(obj)/compressed/vmlinux FORCE
 	$(call if_changed,objcopy)
+endif
 
 endif
 
@@ -78,6 +84,20 @@ else
   endif
 endif
 
+ifeq ($(UIMAGE_LOADADDR),)
+  UIMAGE_LOADADDR=$(shell /bin/bash -c 'printf "0x%08x" \
+					$$[$(CONFIG_DRAM_BASE) + 0x008000]')
+endif
+
+ifeq ($(UIMAGE_ENTRYADDR),)
+  ifeq ($(CONFIG_THUMB2_KERNEL),y)
+    # Set bit 0 to 1 so that "mov pc, rx" switches to Thumb-2 mode
+    UIMAGE_ENTRYADDR?=$(shell echo $(UIMAGE_LOADADDR) | sed -e "s/.$$/1/")
+  else
+    UIMAGE_ENTRYADDR?=$(UIMAGE_LOADADDR)
+  endif
+endif
+
 check_for_multiple_loadaddr = \
 if [ $(words $(UIMAGE_LOADADDR)) -ne 1 ]; then \
 	echo 'multiple (or no) load addresses: $(UIMAGE_LOADADDR)'; \
@@ -86,9 +106,14 @@ if [ $(words $(UIMAGE_LOADADDR)) -ne 1 ]; then \
 	false; \
 fi
 
+ifeq ($(CONFIG_KERNEL_COMPRESS_NONE),y)
+$(obj)/uImage:	$(obj)/Image FORCE
+	$(call if_changed,uimage)
+else
 $(obj)/uImage:	$(obj)/zImage FORCE
 	@$(check_for_multiple_loadaddr)
 	$(call if_changed,uimage)
+endif
 
 $(obj)/bootp/bootp: $(obj)/zImage initrd FORCE
 	$(Q)$(MAKE) $(build)=$(obj)/bootp $@

arch/arm/kernel/traps-v7m.c

@@ -0,0 +1,240 @@
+/*
+ * linux/arch/arm/kernel/traps-v7m.c
+ *
+ * Copyright (C) 2011 Dmitry Cherukhin, Emcraft Systems
+ *
+ * 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 2 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, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#include <linux/module.h>
+#include <linux/sched.h>
+#include <linux/mm.h>
+#include <linux/pagemap.h>
+#include <linux/io.h>
+
+#include <asm/cacheflush.h>
+#include <asm/sections.h>
+#include <asm/page.h>
+#include <asm/setup.h>
+#include <asm/mpu.h>
+#include <asm/mach/arch.h>
+#include <asm/system_misc.h>
+#include <asm/exception.h>
+
+struct nvic_regs {
+	unsigned long	some_regs1[837];	/* +000 */
+	unsigned long	config_control;		/* +d14 */
+	unsigned long	some_regs2[3];		/* +d18 */
+	unsigned long	system_handler_csr;	/* +d24 */
+	unsigned long	local_fault_status;	/* +d28 */
+	unsigned long	hard_fault_status;	/* +d2c */
+	unsigned long	some_regs3[1];		/* +d30 */
+	unsigned long	mfar;			/* +d34 */
+	unsigned long	bfar;			/* +d38 */
+	unsigned long	some_regs4[21];		/* +d3c */
+	unsigned long	mpu_type;               /* +d90 */
+	unsigned long	mpu_control;		/* +d94 */
+	unsigned long	reg_number;		/* +d98 */
+	unsigned long	reg_base;		/* +d9c */
+	unsigned long	reg_attr;		/* +da0 */
+};
+
+#define NVIC_REGS_BASE  0xE000E000
+#define NVIC		((struct nvic_regs *)(NVIC_REGS_BASE))
+
+enum config_control_bits {
+	UNALIGN_TRP	= 0x00000008,
+	DIV_0_TRP	= 0x00000010,
+};
+
+enum system_handler_csr_bits {
+	BUSFAULTENA	= 0x00020000,
+	USGFAULTENA	= 0x00040000,
+};
+
+enum local_fault_status_bits {
+	IBUSERR		= 0x00000100,
+	PRECISERR	= 0x00000200,
+	IMPRECISERR	= 0x00000400,
+	UNSTKERR	= 0x00000800,
+	STKERR		= 0x00001000,
+	BFARVALID	= 0x00008000,
+	UNDEFINSTR	= 0x00010000,
+	INVSTATE	= 0x00020000,
+	INVPC		= 0x00040000,
+	NOCP		= 0x00080000,
+	UNALIGNED	= 0x01000000,
+	DIVBYZERO	= 0x02000000,
+};
+
+enum hard_fault_status_bits {
+	VECTTBL		= 0x00000002,
+	FORCED		= 0x40000000,
+};
+
+enum interrupts {
+	HARDFAULT	= 3,
+	BUSFAULT	= 5,
+	USAGEFAULT	= 6,
+};
+
+struct traps {
+	char	*name;
+	int	test_bit;
+	int	handler;
+};
+
+static struct traps traps[] = {
+	{"Vector Read error",		VECTTBL,	HARDFAULT},
+	{"uCode stack push error",	STKERR,		BUSFAULT},
+	{"uCode stack pop error",	UNSTKERR,	BUSFAULT},
+	{"Escalated to Hard Fault",	FORCED,		HARDFAULT},
+	{"Pre-fetch error",		IBUSERR,	BUSFAULT},
+	{"Precise data bus error",	PRECISERR,	BUSFAULT},
+	{"Imprecise data bus error",	IMPRECISERR,	BUSFAULT},
+	{"No Coprocessor",		NOCP,		USAGEFAULT},
+	{"Undefined Instruction",	UNDEFINSTR,	USAGEFAULT},
+	{"Invalid ISA state",		INVSTATE,	USAGEFAULT},
+	{"Return to invalid PC",	INVPC,		USAGEFAULT},
+	{"Illegal unaligned access",	UNALIGNED,	USAGEFAULT},
+	{"Divide By 0",			DIVBYZERO,	USAGEFAULT},
+	{NULL}
+};
+
+extern void show_regs(struct pt_regs * regs);
+
+/*
+ * The function initializes Bus fault and Usage fault exceptions,
+ * forbids unaligned data access and division by 0.
+ */
+void traps_v7m_init(void){
+	writel(readl(&NVIC->system_handler_csr) | USGFAULTENA | BUSFAULTENA,
+			&NVIC->system_handler_csr);
+	writel(
+#ifndef CONFIG_ARM_V7M_NO_UNALIGN_TRP
+		UNALIGN_TRP |
+#endif
+		DIV_0_TRP | readl(&NVIC->config_control),
+			&NVIC->config_control);
+}
+
+/*
+ * The function prints information about the reason of the exception
+ * @param name		name of current executable (process or kernel)
+ * @param regs		state of registers when the exception occurs
+ * @param in		IPSR, the number of the exception
+ * @param addr		address caused the interrupt, or current pc
+ * @param hstatus	status register for hard fault
+ * @param lstatus	status register for local fault
+ */
+static void traps_v7m_print_message(char *name, struct pt_regs *regs,
+		enum interrupts in, unsigned long addr,
+		unsigned long hstatus, unsigned long lstatus)
+{
+	int i;
+	printk("\n\n%s: fault at 0x%08lx [pc=0x%08lx, sp=0x%08lx]\n",
+			name, addr, instruction_pointer(regs), regs->ARM_sp);
+	for (i = 0; traps[i].name != NULL; ++i) {
+		if ((traps[i].handler == HARDFAULT ? hstatus : lstatus)
+				& traps[i].test_bit) {
+			printk("%s\n", traps[i].name);
+		}
+	}
+	printk("\n");
+}
+
+/*
+ * Common routine for high-level exception handlers.
+ * @param regs		state of registers when the exception occurs
+ * @param in		IPSR, the number of the exception
+ */
+void traps_v7m_common(struct pt_regs *regs, enum interrupts in)
+{
+	unsigned long hstatus;
+	unsigned long lstatus;
+	unsigned long addr;
+
+	hstatus = readl(&NVIC->hard_fault_status);
+	lstatus = readl(&NVIC->local_fault_status);
+
+	if (lstatus & BFARVALID && (in == BUSFAULT ||
+			(in == HARDFAULT && hstatus & FORCED))) {
+		addr = readl(&NVIC->bfar);
+	} else {
+		addr = instruction_pointer(regs);
+	}
+
+	writel(hstatus, &NVIC->hard_fault_status);
+	writel(lstatus, &NVIC->local_fault_status);
+
+#if defined(CONFIG_VFPM)
+	if (lstatus & NOCP) {
+		extern int vfpm_handle_exception(void);
+		if (vfpm_handle_exception()) {
+			return;
+		}
+	}
+#endif
+
+	if (user_mode(regs)) {
+#if defined(CONFIG_DEBUG_USER)
+		extern unsigned int user_debug;
+
+		if (user_debug & UDBG_SEGV) {
+			traps_v7m_print_message(current->comm, regs, in, addr,
+					hstatus, lstatus);
+		}
+#endif
+		if (lstatus & UNDEFINSTR) {
+			send_sig(SIGTRAP, current, 0);
+		}
+		else {
+			send_sig(SIGSEGV, current, 0);
+		}
+	} else {
+		traps_v7m_print_message("KERNEL", regs, in, addr,
+				hstatus, lstatus);
+		show_regs(regs);
+		panic(0);
+	}
+}
+
+/*
+ * High-level exception handler for exception 3 (Hard fault).
+ * @param regs		state of registers when the exception occurs
+ */
+asmlinkage void __exception_irq_entry do_hardfault(struct pt_regs *regs)
+{
+	traps_v7m_common(regs, HARDFAULT);
+}
+
+/*
+ * High-level exception handler for exception 5 (Bus fault).
+ * @param regs		state of registers when the exception occurs
+ */
+asmlinkage void __exception_irq_entry do_busfault(struct pt_regs *regs)
+{
+	traps_v7m_common(regs, BUSFAULT);
+}
+
+/*
+ * High-level exception handler for exception 6 (Usage fault).
+ * @param regs		state of registers when the exception occurs
+ */
+asmlinkage void __exception_irq_entry do_usagefault(struct pt_regs *regs)
+{
+	traps_v7m_common(regs, USAGEFAULT);
+}
+