Merge branch 'sh/dwarf-unwinder'

arch/sh/Kconfig.debug

@@ -110,6 +110,14 @@ config DUMP_CODE
 
 	  Those looking for more verbose debugging output should say Y.
 
+config DWARF_UNWINDER
+	bool "Enable the DWARF unwinder for stacktraces"
+	select FRAME_POINTER
+	default n
+	help
+	  Enabling this option will make stacktraces more accurate, at
+	  the cost of an increase in overall kernel size.
+
 config SH_NO_BSS_INIT
 	bool "Avoid zeroing BSS (to speed-up startup on suitable platforms)"
 	depends on DEBUG_KERNEL

arch/sh/Makefile

@@ -191,6 +191,10 @@ ifeq ($(CONFIG_MCOUNT),y)
   KBUILD_CFLAGS += -pg
 endif
 
+ifeq ($(CONFIG_DWARF_UNWINDER),y)
+  KBUILD_CFLAGS += -fasynchronous-unwind-tables
+endif
+
 libs-$(CONFIG_SUPERH32)		:= arch/sh/lib/	$(libs-y)
 libs-$(CONFIG_SUPERH64)		:= arch/sh/lib64/ $(libs-y)
 

arch/sh/include/asm/dwarf.h

+/*
+ * Copyright (C) 2009 Matt Fleming <matt@console-pimps.org>
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ */
+#ifndef __ASM_SH_DWARF_H
+#define __ASM_SH_DWARF_H
+
+#ifdef CONFIG_DWARF_UNWINDER
+
+/*
+ * DWARF expression operations
+ */
+#define DW_OP_addr	0x03
+#define DW_OP_deref	0x06
+#define DW_OP_const1u	0x08
+#define DW_OP_const1s	0x09
+#define DW_OP_const2u	0x0a
+#define DW_OP_const2s	0x0b
+#define DW_OP_const4u	0x0c
+#define DW_OP_const4s	0x0d
+#define DW_OP_const8u	0x0e
+#define DW_OP_const8s	0x0f
+#define DW_OP_constu	0x10
+#define DW_OP_consts	0x11
+#define DW_OP_dup	0x12
+#define DW_OP_drop	0x13
+#define DW_OP_over	0x14
+#define DW_OP_pick	0x15
+#define DW_OP_swap	0x16
+#define DW_OP_rot	0x17
+#define DW_OP_xderef	0x18
+#define DW_OP_abs	0x19
+#define DW_OP_and	0x1a
+#define DW_OP_div	0x1b
+#define DW_OP_minus	0x1c
+#define DW_OP_mod	0x1d
+#define DW_OP_mul	0x1e
+#define DW_OP_neg	0x1f
+#define DW_OP_not	0x20
+#define DW_OP_or	0x21
+#define DW_OP_plus	0x22
+#define DW_OP_plus_uconst	0x23
+#define DW_OP_shl	0x24
+#define DW_OP_shr	0x25
+#define DW_OP_shra	0x26
+#define DW_OP_xor	0x27
+#define DW_OP_skip	0x2f
+#define DW_OP_bra	0x28
+#define DW_OP_eq	0x29
+#define DW_OP_ge	0x2a
+#define DW_OP_gt	0x2b
+#define DW_OP_le	0x2c
+#define DW_OP_lt	0x2d
+#define DW_OP_ne	0x2e
+#define DW_OP_lit0	0x30
+#define DW_OP_lit1	0x31
+#define DW_OP_lit2	0x32
+#define DW_OP_lit3	0x33
+#define DW_OP_lit4	0x34
+#define DW_OP_lit5	0x35
+#define DW_OP_lit6	0x36
+#define DW_OP_lit7	0x37
+#define DW_OP_lit8	0x38
+#define DW_OP_lit9	0x39
+#define DW_OP_lit10	0x3a
+#define DW_OP_lit11	0x3b
+#define DW_OP_lit12	0x3c
+#define DW_OP_lit13	0x3d
+#define DW_OP_lit14	0x3e
+#define DW_OP_lit15	0x3f
+#define DW_OP_lit16	0x40
+#define DW_OP_lit17	0x41
+#define DW_OP_lit18	0x42
+#define DW_OP_lit19	0x43
+#define DW_OP_lit20	0x44
+#define DW_OP_lit21	0x45
+#define DW_OP_lit22	0x46
+#define DW_OP_lit23	0x47
+#define DW_OP_lit24	0x48
+#define DW_OP_lit25	0x49
+#define DW_OP_lit26	0x4a
+#define DW_OP_lit27	0x4b
+#define DW_OP_lit28	0x4c
+#define DW_OP_lit29	0x4d
+#define DW_OP_lit30	0x4e
+#define DW_OP_lit31	0x4f
+#define DW_OP_reg0	0x50
+#define DW_OP_reg1	0x51
+#define DW_OP_reg2	0x52
+#define DW_OP_reg3	0x53
+#define DW_OP_reg4	0x54
+#define DW_OP_reg5	0x55
+#define DW_OP_reg6	0x56
+#define DW_OP_reg7	0x57
+#define DW_OP_reg8	0x58
+#define DW_OP_reg9	0x59
+#define DW_OP_reg10	0x5a
+#define DW_OP_reg11	0x5b
+#define DW_OP_reg12	0x5c
+#define DW_OP_reg13	0x5d
+#define DW_OP_reg14	0x5e
+#define DW_OP_reg15	0x5f
+#define DW_OP_reg16	0x60
+#define DW_OP_reg17	0x61
+#define DW_OP_reg18	0x62
+#define DW_OP_reg19	0x63
+#define DW_OP_reg20	0x64
+#define DW_OP_reg21	0x65
+#define DW_OP_reg22	0x66
+#define DW_OP_reg23	0x67
+#define DW_OP_reg24	0x68
+#define DW_OP_reg25	0x69
+#define DW_OP_reg26	0x6a
+#define DW_OP_reg27	0x6b
+#define DW_OP_reg28	0x6c
+#define DW_OP_reg29	0x6d
+#define DW_OP_reg30	0x6e
+#define DW_OP_reg31	0x6f
+#define DW_OP_breg0	0x70
+#define DW_OP_breg1	0x71
+#define DW_OP_breg2	0x72
+#define DW_OP_breg3	0x73
+#define DW_OP_breg4	0x74
+#define DW_OP_breg5	0x75
+#define DW_OP_breg6	0x76
+#define DW_OP_breg7	0x77
+#define DW_OP_breg8	0x78
+#define DW_OP_breg9	0x79
+#define DW_OP_breg10	0x7a
+#define DW_OP_breg11	0x7b
+#define DW_OP_breg12	0x7c
+#define DW_OP_breg13	0x7d
+#define DW_OP_breg14	0x7e
+#define DW_OP_breg15	0x7f
+#define DW_OP_breg16	0x80
+#define DW_OP_breg17	0x81
+#define DW_OP_breg18	0x82
+#define DW_OP_breg19	0x83
+#define DW_OP_breg20	0x84
+#define DW_OP_breg21	0x85
+#define DW_OP_breg22	0x86
+#define DW_OP_breg23	0x87
+#define DW_OP_breg24	0x88
+#define DW_OP_breg25	0x89
+#define DW_OP_breg26	0x8a
+#define DW_OP_breg27	0x8b
+#define DW_OP_breg28	0x8c
+#define DW_OP_breg29	0x8d
+#define DW_OP_breg30	0x8e
+#define DW_OP_breg31	0x8f
+#define DW_OP_regx	0x90
+#define DW_OP_fbreg	0x91
+#define DW_OP_bregx	0x92
+#define DW_OP_piece	0x93
+#define DW_OP_deref_size	0x94
+#define DW_OP_xderef_size	0x95
+#define DW_OP_nop	0x96
+#define DW_OP_push_object_address	0x97
+#define DW_OP_call2	0x98
+#define DW_OP_call4	0x99
+#define DW_OP_call_ref	0x9a
+#define DW_OP_form_tls_address	0x9b
+#define DW_OP_call_frame_cfa	0x9c
+#define DW_OP_bit_piece	0x9d
+#define DW_OP_lo_user	0xe0
+#define DW_OP_hi_user	0xff
+
+/*
+ * Addresses used in FDE entries in the .eh_frame section may be encoded
+ * using one of the following encodings.
+ */
+#define DW_EH_PE_absptr	0x00
+#define DW_EH_PE_omit	0xff
+#define DW_EH_PE_uleb128	0x01
+#define DW_EH_PE_udata2	0x02
+#define DW_EH_PE_udata4	0x03
+#define DW_EH_PE_udata8	0x04
+#define DW_EH_PE_sleb128	0x09
+#define DW_EH_PE_sdata2	0x0a
+#define DW_EH_PE_sdata4	0x0b
+#define DW_EH_PE_sdata8	0x0c
+#define DW_EH_PE_signed	0x09
+
+#define DW_EH_PE_pcrel	0x10
+
+/*
+ * The architecture-specific register number that contains the return
+ * address in the .debug_frame table.
+ */
+#define DWARF_ARCH_RA_REG	17
+
+#ifndef __ASSEMBLY__
+/*
+ * Read either the frame pointer (r14) or the stack pointer (r15).
+ * NOTE: this MUST be inlined.
+ */
+static __always_inline unsigned long dwarf_read_arch_reg(unsigned int reg)
+{
+	unsigned long value;
+
+	switch (reg) {
+	case 14:
+		__asm__ __volatile__("mov r14, %0\n" : "=r" (value));
+		break;
+	case 15:
+		__asm__ __volatile__("mov r15, %0\n" : "=r" (value));
+		break;
+	default:
+		BUG();
+	}
+
+	return value;
+}
+
+/**
+ *	dwarf_cie - Common Information Entry
+ */
+struct dwarf_cie {
+	unsigned long length;
+	unsigned long cie_id;
+	unsigned char version;
+	const char *augmentation;
+	unsigned int code_alignment_factor;
+	int data_alignment_factor;
+
+	/* Which column in the rule table represents return addr of func. */
+	unsigned int return_address_reg;
+
+	unsigned char *initial_instructions;
+	unsigned char *instructions_end;
+
+	unsigned char encoding;
+
+	unsigned long cie_pointer;
+
+	struct list_head link;
+
+	unsigned long flags;
+#define DWARF_CIE_Z_AUGMENTATION	(1 << 0)
+};
+
+/**
+ *	dwarf_fde - Frame Description Entry
+ */
+struct dwarf_fde {
+	unsigned long length;
+	unsigned long cie_pointer;
+	struct dwarf_cie *cie;
+	unsigned long initial_location;
+	unsigned long address_range;
+	unsigned char *instructions;
+	unsigned char *end;
+	struct list_head link;
+};
+
+/**
+ *	dwarf_frame - DWARF information for a frame in the call stack
+ */
+struct dwarf_frame {
+	struct dwarf_frame *prev, *next;
+
+	unsigned long pc;
+
+	struct dwarf_reg *regs;
+	unsigned int num_regs;	/* how many regs are allocated? */
+
+	unsigned int depth;	/* what level are we in the callstack? */
+
+	unsigned long cfa;
+
+	/* Valid when DW_FRAME_CFA_REG_OFFSET is set in flags */
+	unsigned int cfa_register;
+	unsigned int cfa_offset;
+
+	/* Valid when DW_FRAME_CFA_REG_EXP is set in flags */
+	unsigned char *cfa_expr;
+	unsigned int cfa_expr_len;
+
+	unsigned long flags;
+#define DWARF_FRAME_CFA_REG_OFFSET	(1 << 0)
+#define DWARF_FRAME_CFA_REG_EXP		(1 << 1)
+
+	unsigned long return_addr;
+};
+
+/**
+ *	dwarf_reg - DWARF register
+ *	@flags: Describes how to calculate the value of this register
+ */
+struct dwarf_reg {
+	unsigned long addr;
+	unsigned long flags;
+#define DWARF_REG_OFFSET	(1 << 0)
+};
+
+/**
+ *	dwarf_stack - a DWARF stack contains a collection of DWARF frames
+ *	@depth: the number of frames in the stack
+ *	@level: an array of DWARF frames, indexed by stack level
+ *
+ */
+struct dwarf_stack {
+	unsigned int depth;
+	struct dwarf_frame **level;
+};
+
+/*
+ * Call Frame instruction opcodes.
+ */
+#define DW_CFA_advance_loc	0x40
+#define DW_CFA_offset		0x80
+#define DW_CFA_restore		0xc0
+#define DW_CFA_nop		0x00
+#define DW_CFA_set_loc		0x01
+#define DW_CFA_advance_loc1	0x02
+#define DW_CFA_advance_loc2	0x03
+#define DW_CFA_advance_loc4	0x04
+#define DW_CFA_offset_extended	0x05
+#define DW_CFA_restore_extended	0x06
+#define DW_CFA_undefined	0x07
+#define DW_CFA_same_value	0x08
+#define DW_CFA_register		0x09
+#define DW_CFA_remember_state	0x0a
+#define DW_CFA_restore_state	0x0b
+#define DW_CFA_def_cfa		0x0c
+#define DW_CFA_def_cfa_register	0x0d
+#define DW_CFA_def_cfa_offset	0x0e
+#define DW_CFA_def_cfa_expression	0x0f
+#define DW_CFA_expression	0x10
+#define DW_CFA_offset_extended_sf	0x11
+#define DW_CFA_def_cfa_sf	0x12
+#define DW_CFA_def_cfa_offset_sf	0x13
+#define DW_CFA_val_offset	0x14
+#define DW_CFA_val_offset_sf	0x15
+#define DW_CFA_val_expression	0x16
+#define DW_CFA_lo_user		0x1c
+#define DW_CFA_hi_user		0x3f
+
+/*
+ * Some call frame instructions encode their operands in the opcode. We
+ * need some helper functions to extract both the opcode and operands
+ * from an instruction.
+ */
+static inline unsigned int DW_CFA_opcode(unsigned long insn)
+{
+	return (insn & 0xc0);
+}
+
+static inline unsigned int DW_CFA_operand(unsigned long insn)
+{
+	return (insn & 0x3f);
+}
+
+#define DW_EH_FRAME_CIE	0		/* .eh_frame CIE IDs are 0 */
+#define DW_CIE_ID	0xffffffff
+#define DW64_CIE_ID	0xffffffffffffffffULL
+
+/*
+ * DWARF FDE/CIE length field values.
+ */
+#define DW_EXT_LO	0xfffffff0
+#define DW_EXT_HI	0xffffffff
+#define DW_EXT_DWARF64	DW_EXT_HI
+
+extern void dwarf_unwinder_init(void);
+
+extern struct dwarf_frame *dwarf_unwind_stack(unsigned long,
+					      struct dwarf_frame *);
+#endif /* __ASSEMBLY__ */
+
+#define CFI_STARTPROC	.cfi_startproc
+#define CFI_ENDPROC	.cfi_endproc
+#define CFI_DEF_CFA	.cfi_def_cfa
+#define CFI_REGISTER	.cfi_register
+#define CFI_REL_OFFSET	.cfi_rel_offset
+
+#else
+
+/*
+ * Use the asm comment character to ignore the rest of the line.
+ */
+#define CFI_IGNORE	!
+
+#define CFI_STARTPROC	CFI_IGNORE
+#define CFI_ENDPROC	CFI_IGNORE
+#define CFI_DEF_CFA	CFI_IGNORE
+#define CFI_REGISTER	CFI_IGNORE
+#define CFI_REL_OFFSET	CFI_IGNORE
+
+#ifndef __ASSEMBLY__
+static inline void dwarf_unwinder_init(void)
+{
+}
+#endif
+
+#endif /* CONFIG_DWARF_UNWINDER */
+
+#endif /* __ASM_SH_DWARF_H */

arch/sh/include/asm/entry-macros.S

@@ -108,3 +108,15 @@
 #else
 # define PREF(x)	nop
 #endif
+
+	/*
+	 * Macro for use within assembly. Because the DWARF unwinder
+	 * needs to use the frame register to unwind the stack, we
+	 * need to setup r14 with the value of the stack pointer as
+	 * the return address is usually on the stack somewhere.
+	 */
+	.macro	setup_frame_reg
+#ifdef CONFIG_DWARF_UNWINDER
+	mov	r15, r14
+#endif
+	.endm

arch/sh/include/asm/sections.h

@@ -7,6 +7,7 @@ extern void __nosave_begin, __nosave_end;
 extern long __machvec_start, __machvec_end;
 extern char __uncached_start, __uncached_end;
 extern char _ebss[];
+extern char __start_eh_frame[], __stop_eh_frame[];
 
 #endif /* __ASM_SH_SECTIONS_H */
 

arch/sh/include/asm/vmlinux.lds.h

+#ifndef __ASM_SH_VMLINUX_LDS_H
+#define __ASM_SH_VMLINUX_LDS_H
+
+#include <asm-generic/vmlinux.lds.h>
+
+#ifdef CONFIG_DWARF_UNWINDER
+#define DWARF_EH_FRAME							\
+	.eh_frame : AT(ADDR(.eh_frame) - LOAD_OFFSET) {			\
+		  VMLINUX_SYMBOL(__start_eh_frame) = .;			\
+		  *(.eh_frame)						\
+		  VMLINUX_SYMBOL(__stop_eh_frame) = .;			\
+	}
+#else
+#define DWARF_EH_FRAME
+#endif
+
+#endif /* __ASM_SH_VMLINUX_LDS_H */

arch/sh/kernel/Makefile_32

@@ -33,6 +33,7 @@ obj-$(CONFIG_FTRACE_SYSCALLS)	+= ftrace.o
 obj-$(CONFIG_FUNCTION_GRAPH_TRACER) += ftrace.o
 obj-$(CONFIG_DUMP_CODE)		+= disassemble.o
 obj-$(CONFIG_HIBERNATION)	+= swsusp.o
+obj-$(CONFIG_DWARF_UNWINDER)	+= dwarf.o
 
 obj-$(CONFIG_GENERIC_CLOCKEVENTS_BROADCAST)	+= localtimer.o
 

arch/sh/kernel/Makefile_64

@@ -13,6 +13,7 @@ obj-$(CONFIG_CRASH_DUMP)	+= crash_dump.o
 obj-$(CONFIG_STACKTRACE)	+= stacktrace.o
 obj-$(CONFIG_IO_TRAPPED)	+= io_trapped.o
 obj-$(CONFIG_GENERIC_GPIO)	+= gpio.o
+obj-$(CONFIG_DWARF_UNWINDER)	+= dwarf.o
 
 obj-$(CONFIG_GENERIC_CLOCKEVENTS_BROADCAST)	+= localtimer.o
 

arch/sh/kernel/cpu/sh3/entry.S

@@ -137,6 +137,7 @@ ENTRY(tlb_protection_violation_store)
 	 mov	#1, r5
 
 call_dpf:
+	setup_frame_reg
 	mov.l	1f, r0
 	mov	r5, r8
 	mov.l	@r0, r6

arch/sh/kernel/entry-common.S

@@ -43,6 +43,7 @@
  *	syscall #
  *
  */
+#include <asm/dwarf.h>
 
 #if defined(CONFIG_PREEMPT)
 #  define preempt_stop()	cli ; TRACE_IRQS_OFF
@@ -66,6 +67,11 @@ ENTRY(exception_error)
 
 	.align	2
 ret_from_exception:
+	CFI_STARTPROC simple
+	CFI_DEF_CFA r14, 0
+	CFI_REL_OFFSET 17, 64
+	CFI_REL_OFFSET 15, 0
+	CFI_REL_OFFSET 14, 56
 	preempt_stop()
 ENTRY(ret_from_irq)
 	!
@@ -240,6 +246,7 @@ debug_trap:
 	 nop
 	bra	__restore_all
 	 nop
+	CFI_ENDPROC
 
 	.align	2
 1:	.long	debug_trap_table
@@ -285,6 +292,7 @@ ret_from_fork:
  * system calls and debug traps through their respective jump tables.
  */
 ENTRY(system_call)
+	setup_frame_reg
 #if !defined(CONFIG_CPU_SH2)
 	mov.l	1f, r9
 	mov.l	@r9, r8		! Read from TRA (Trap Address) Register

arch/sh/kernel/irq.c

@@ -14,6 +14,7 @@
 #include <asm/processor.h>
 #include <asm/machvec.h>
 #include <asm/uaccess.h>
+#include <asm/dwarf.h>
 #include <asm/thread_info.h>
 #include <cpu/mmu_context.h>
 
@@ -261,6 +262,9 @@ void __init init_IRQ(void)
 		sh_mv.mv_init_irq();
 
 	irq_ctx_init(smp_processor_id());
+
+	/* This needs to be early, but not too early.. */
+	dwarf_unwinder_init();
 }
 
 #ifdef CONFIG_SPARSE_IRQ

arch/sh/kernel/vmlinux.lds.S

@@ -12,7 +12,7 @@ OUTPUT_ARCH(sh)
 
 #include <asm/thread_info.h>
 #include <asm/cache.h>
-#include <asm-generic/vmlinux.lds.h>
+#include <asm/vmlinux.lds.h>
 
 ENTRY(_start)
 SECTIONS
@@ -70,6 +70,8 @@ SECTIONS
 
 	_edata = .;			/* End of data section */
 
+	DWARF_EH_FRAME
+
 	. = ALIGN(PAGE_SIZE);		/* Init code and data */
 	__init_begin = .;
 	INIT_TEXT_SECTION(PAGE_SIZE)