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Merge branch 'sh/dwarf-unwinder'

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This commit is contained in:
Paul Mundt 2009-08-14 05:10:57 +09:00
commit 718dbf376a
13 changed files with 1363 additions and 1 deletions
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8
arch/sh/Kconfig.debug
View file

@ -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

4
arch/sh/Makefile
View file

@ -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)

402
arch/sh/include/asm/dwarf.h Normal file
View file

@ -0,0 +1,402 @@
/*
* 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 */

12
arch/sh/include/asm/entry-macros.S
View file

@ -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

1
arch/sh/include/asm/sections.h
View file

@ -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 */

17
arch/sh/include/asm/vmlinux.lds.h Normal file
View file

@ -0,0 +1,17 @@
#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 */

1
arch/sh/kernel/Makefile_32
View file

@ -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

1
arch/sh/kernel/Makefile_64
View file

@ -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

1
arch/sh/kernel/cpu/sh3/entry.S
View file

@ -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

901
arch/sh/kernel/dwarf.c Normal file
View file

@ -0,0 +1,901 @@
/*
* 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.
*
* This is an implementation of a DWARF unwinder. Its main purpose is
* for generating stacktrace information. Based on the DWARF 3
* specification from http://www.dwarfstd.org.
*
* TODO:
* - DWARF64 doesn't work.
*/
/* #define DEBUG */
#include <linux/kernel.h>
#include <linux/io.h>
#include <linux/list.h>
#include <linux/mm.h>
#include <asm/dwarf.h>
#include <asm/unwinder.h>
#include <asm/sections.h>
#include <asm/unaligned.h>
#include <asm/dwarf.h>
#include <asm/stacktrace.h>
static LIST_HEAD(dwarf_cie_list);
DEFINE_SPINLOCK(dwarf_cie_lock);
static LIST_HEAD(dwarf_fde_list);
DEFINE_SPINLOCK(dwarf_fde_lock);
static struct dwarf_cie *cached_cie;
/*
* Figure out whether we need to allocate some dwarf registers. If dwarf
* registers have already been allocated then we may need to realloc
* them. "reg" is a register number that we need to be able to access
* after this call.
*
* Register numbers start at zero, therefore we need to allocate space
* for "reg" + 1 registers.
*/
static void dwarf_frame_alloc_regs(struct dwarf_frame *frame,
unsigned int reg)
{
struct dwarf_reg *regs;
unsigned int num_regs = reg + 1;
size_t new_size;
size_t old_size;
new_size = num_regs * sizeof(*regs);
old_size = frame->num_regs * sizeof(*regs);
/* Fast path: don't allocate any regs if we've already got enough. */
if (frame->num_regs >= num_regs)
return;
regs = kzalloc(new_size, GFP_KERNEL);
if (!regs) {
printk(KERN_WARNING "Unable to allocate DWARF registers\n");
/*
* Let's just bomb hard here, we have no way to
* gracefully recover.
*/
BUG();
}
if (frame->regs) {
memcpy(regs, frame->regs, old_size);
kfree(frame->regs);
}
frame->regs = regs;
frame->num_regs = num_regs;
}
/**
* dwarf_read_addr - read dwarf data
* @src: source address of data
* @dst: destination address to store the data to
*
* Read 'n' bytes from @src, where 'n' is the size of an address on
* the native machine. We return the number of bytes read, which
* should always be 'n'. We also have to be careful when reading
* from @src and writing to @dst, because they can be arbitrarily
* aligned. Return 'n' - the number of bytes read.
*/
static inline int dwarf_read_addr(unsigned long *src, unsigned long *dst)
{
u32 val = get_unaligned(src);
put_unaligned(val, dst);
return sizeof(unsigned long *);
}
/**
* dwarf_read_uleb128 - read unsigned LEB128 data
* @addr: the address where the ULEB128 data is stored
* @ret: address to store the result
*
* Decode an unsigned LEB128 encoded datum. The algorithm is taken
* from Appendix C of the DWARF 3 spec. For information on the
* encodings refer to section "7.6 - Variable Length Data". Return
* the number of bytes read.
*/
static inline unsigned long dwarf_read_uleb128(char *addr, unsigned int *ret)
{
unsigned int result;
unsigned char byte;
int shift, count;
result = 0;
shift = 0;
count = 0;
while (1) {
byte = __raw_readb(addr);
addr++;
count++;
result |= (byte & 0x7f) << shift;
shift += 7;
if (!(byte & 0x80))
break;
}
*ret = result;
return count;
}
/**
* dwarf_read_leb128 - read signed LEB128 data
* @addr: the address of the LEB128 encoded data
* @ret: address to store the result
*
* Decode signed LEB128 data. The algorithm is taken from Appendix
* C of the DWARF 3 spec. Return the number of bytes read.
*/
static inline unsigned long dwarf_read_leb128(char *addr, int *ret)
{
unsigned char byte;
int result, shift;
int num_bits;
int count;
result = 0;
shift = 0;
count = 0;
while (1) {
byte = __raw_readb(addr);
addr++;
result |= (byte & 0x7f) << shift;
shift += 7;
count++;
if (!(byte & 0x80))
break;
}
/* The number of bits in a signed integer. */
num_bits = 8 * sizeof(result);
if ((shift < num_bits) && (byte & 0x40))
result |= (-1 << shift);
*ret = result;
return count;
}
/**
* dwarf_read_encoded_value - return the decoded value at @addr
* @addr: the address of the encoded value
* @val: where to write the decoded value
* @encoding: the encoding with which we can decode @addr
*
* GCC emits encoded address in the .eh_frame FDE entries. Decode
* the value at @addr using @encoding. The decoded value is written
* to @val and the number of bytes read is returned.
*/
static int dwarf_read_encoded_value(char *addr, unsigned long *val,
char encoding)
{
unsigned long decoded_addr = 0;
int count = 0;
switch (encoding & 0x70) {
case DW_EH_PE_absptr:
break;
case DW_EH_PE_pcrel:
decoded_addr = (unsigned long)addr;
break;
default:
pr_debug("encoding=0x%x\n", (encoding & 0x70));
BUG();
}
if ((encoding & 0x07) == 0x00)
encoding |= DW_EH_PE_udata4;
switch (encoding & 0x0f) {
case DW_EH_PE_sdata4:
case DW_EH_PE_udata4:
count += 4;
decoded_addr += get_unaligned((u32 *)addr);
__raw_writel(decoded_addr, val);
break;
default:
pr_debug("encoding=0x%x\n", encoding);
BUG();
}
return count;
}
/**
* dwarf_entry_len - return the length of an FDE or CIE
* @addr: the address of the entry
* @len: the length of the entry
*
* Read the initial_length field of the entry and store the size of
* the entry in @len. We return the number of bytes read. Return a
* count of 0 on error.
*/
static inline int dwarf_entry_len(char *addr, unsigned long *len)
{
u32 initial_len;
int count;
initial_len = get_unaligned((u32 *)addr);
count = 4;
/*
* An initial length field value in the range DW_LEN_EXT_LO -
* DW_LEN_EXT_HI indicates an extension, and should not be
* interpreted as a length. The only extension that we currently
* understand is the use of DWARF64 addresses.
*/
if (initial_len >= DW_EXT_LO && initial_len <= DW_EXT_HI) {
/*
* The 64-bit length field immediately follows the
* compulsory 32-bit length field.
*/
if (initial_len == DW_EXT_DWARF64) {
*len = get_unaligned((u64 *)addr + 4);
count = 12;
} else {
printk(KERN_WARNING "Unknown DWARF extension\n");
count = 0;
}
} else
*len = initial_len;
return count;
}
/**
* dwarf_lookup_cie - locate the cie
* @cie_ptr: pointer to help with lookup
*/
static struct dwarf_cie *dwarf_lookup_cie(unsigned long cie_ptr)
{
struct dwarf_cie *cie, *n;
unsigned long flags;
spin_lock_irqsave(&dwarf_cie_lock, flags);
/*
* We've cached the last CIE we looked up because chances are
* that the FDE wants this CIE.
*/
if (cached_cie && cached_cie->cie_pointer == cie_ptr) {
cie = cached_cie;
goto out;
}
list_for_each_entry_safe(cie, n, &dwarf_cie_list, link) {
if (cie->cie_pointer == cie_ptr) {
cached_cie = cie;
break;
}
}
/* Couldn't find the entry in the list. */
if (&cie->link == &dwarf_cie_list)
cie = NULL;
out:
spin_unlock_irqrestore(&dwarf_cie_lock, flags);
return cie;
}
/**
* dwarf_lookup_fde - locate the FDE that covers pc
* @pc: the program counter
*/
struct dwarf_fde *dwarf_lookup_fde(unsigned long pc)
{
unsigned long flags;
struct dwarf_fde *fde, *n;
spin_lock_irqsave(&dwarf_fde_lock, flags);
list_for_each_entry_safe(fde, n, &dwarf_fde_list, link) {
unsigned long start, end;
start = fde->initial_location;
end = fde->initial_location + fde->address_range;
if (pc >= start && pc < end)
break;
}
/* Couldn't find the entry in the list. */
if (&fde->link == &dwarf_fde_list)
fde = NULL;
spin_unlock_irqrestore(&dwarf_fde_lock, flags);
return fde;
}
/**
* dwarf_cfa_execute_insns - execute instructions to calculate a CFA
* @insn_start: address of the first instruction
* @insn_end: address of the last instruction
* @cie: the CIE for this function
* @fde: the FDE for this function
* @frame: the instructions calculate the CFA for this frame
* @pc: the program counter of the address we're interested in
* @define_ra: keep executing insns until the return addr reg is defined?
*
* Execute the Call Frame instruction sequence starting at
* @insn_start and ending at @insn_end. The instructions describe
* how to calculate the Canonical Frame Address of a stackframe.
* Store the results in @frame.
*/
static int dwarf_cfa_execute_insns(unsigned char *insn_start,
unsigned char *insn_end,
struct dwarf_cie *cie,
struct dwarf_fde *fde,
struct dwarf_frame *frame,
unsigned long pc,
bool define_ra)
{
unsigned char insn;
unsigned char *current_insn;
unsigned int count, delta, reg, expr_len, offset;
bool seen_ra_reg;
current_insn = insn_start;
/*
* If we're executing instructions for the dwarf_unwind_stack()
* FDE we need to keep executing instructions until the value of
* DWARF_ARCH_RA_REG is defined. See the comment in
* dwarf_unwind_stack() for more details.
*/
if (define_ra)
seen_ra_reg = false;
else
seen_ra_reg = true;
while (current_insn < insn_end && (frame->pc <= pc || !seen_ra_reg) ) {
insn = __raw_readb(current_insn++);
if (!seen_ra_reg) {
if (frame->num_regs >= DWARF_ARCH_RA_REG &&
frame->regs[DWARF_ARCH_RA_REG].flags)
seen_ra_reg = true;
}
/*
* Firstly, handle the opcodes that embed their operands
* in the instructions.
*/
switch (DW_CFA_opcode(insn)) {
case DW_CFA_advance_loc:
delta = DW_CFA_operand(insn);
delta *= cie->code_alignment_factor;
frame->pc += delta;
continue;
/* NOTREACHED */
case DW_CFA_offset:
reg = DW_CFA_operand(insn);
count = dwarf_read_uleb128(current_insn, &offset);
current_insn += count;
offset *= cie->data_alignment_factor;
dwarf_frame_alloc_regs(frame, reg);
frame->regs[reg].addr = offset;
frame->regs[reg].flags |= DWARF_REG_OFFSET;
continue;
/* NOTREACHED */
case DW_CFA_restore:
reg = DW_CFA_operand(insn);
continue;
/* NOTREACHED */
}
/*
* Secondly, handle the opcodes that don't embed their
* operands in the instruction.
*/
switch (insn) {
case DW_CFA_nop:
continue;
case DW_CFA_advance_loc1:
delta = *current_insn++;
frame->pc += delta * cie->code_alignment_factor;
break;
case DW_CFA_advance_loc2:
delta = get_unaligned((u16 *)current_insn);
current_insn += 2;
frame->pc += delta * cie->code_alignment_factor;
break;
case DW_CFA_advance_loc4:
delta = get_unaligned((u32 *)current_insn);
current_insn += 4;
frame->pc += delta * cie->code_alignment_factor;
break;
case DW_CFA_offset_extended:
count = dwarf_read_uleb128(current_insn, &reg);
current_insn += count;
count = dwarf_read_uleb128(current_insn, &offset);
current_insn += count;
offset *= cie->data_alignment_factor;
break;
case DW_CFA_restore_extended:
count = dwarf_read_uleb128(current_insn, &reg);
current_insn += count;
break;
case DW_CFA_undefined:
count = dwarf_read_uleb128(current_insn, &reg);
current_insn += count;
break;
case DW_CFA_def_cfa:
count = dwarf_read_uleb128(current_insn,
&frame->cfa_register);
current_insn += count;
count = dwarf_read_uleb128(current_insn,
&frame->cfa_offset);
current_insn += count;
frame->flags |= DWARF_FRAME_CFA_REG_OFFSET;
break;
case DW_CFA_def_cfa_register:
count = dwarf_read_uleb128(current_insn,
&frame->cfa_register);
current_insn += count;
frame->flags |= DWARF_FRAME_CFA_REG_OFFSET;
break;
case DW_CFA_def_cfa_offset:
count = dwarf_read_uleb128(current_insn, &offset);
current_insn += count;
frame->cfa_offset = offset;
break;
case DW_CFA_def_cfa_expression:
count = dwarf_read_uleb128(current_insn, &expr_len);
current_insn += count;
frame->cfa_expr = current_insn;
frame->cfa_expr_len = expr_len;
current_insn += expr_len;
frame->flags |= DWARF_FRAME_CFA_REG_EXP;
break;
case DW_CFA_offset_extended_sf:
count = dwarf_read_uleb128(current_insn, &reg);
current_insn += count;
count = dwarf_read_leb128(current_insn, &offset);
current_insn += count;
offset *= cie->data_alignment_factor;
dwarf_frame_alloc_regs(frame, reg);
frame->regs[reg].flags |= DWARF_REG_OFFSET;
frame->regs[reg].addr = offset;
break;
case DW_CFA_val_offset:
count = dwarf_read_uleb128(current_insn, &reg);
current_insn += count;
count = dwarf_read_leb128(current_insn, &offset);
offset *= cie->data_alignment_factor;
frame->regs[reg].flags |= DWARF_REG_OFFSET;
frame->regs[reg].addr = offset;
break;
default:
pr_debug("unhandled DWARF instruction 0x%x\n", insn);
break;
}
}
return 0;
}
/**
* dwarf_unwind_stack - recursively unwind the stack
* @pc: address of the function to unwind
* @prev: struct dwarf_frame of the previous stackframe on the callstack
*
* Return a struct dwarf_frame representing the most recent frame
* on the callstack. Each of the lower (older) stack frames are
* linked via the "prev" member.
*/
struct dwarf_frame *dwarf_unwind_stack(unsigned long pc,
struct dwarf_frame *prev)
{
struct dwarf_frame *frame;
struct dwarf_cie *cie;
struct dwarf_fde *fde;
unsigned long addr;
int i, offset;
bool define_ra = false;
/*
* If this is the first invocation of this recursive function we
* need get the contents of a physical register to get the CFA
* in order to begin the virtual unwinding of the stack.
*
* Setting "define_ra" to true indictates that we want
* dwarf_cfa_execute_insns() to continue executing instructions
* until we know how to calculate the value of DWARF_ARCH_RA_REG
* (which we need in order to kick off the whole unwinding
* process).
*
* NOTE: the return address is guaranteed to be setup by the
* time this function makes its first function call.
*/
if (!pc && !prev) {
pc = (unsigned long)&dwarf_unwind_stack;
define_ra = true;
}
frame = kzalloc(sizeof(*frame), GFP_KERNEL);
if (!frame)
return NULL;
frame->prev = prev;
fde = dwarf_lookup_fde(pc);
if (!fde) {
/*
* This is our normal exit path - the one that stops the
* recursion. There's two reasons why we might exit
* here,
*
* a) pc has no asscociated DWARF frame info and so
* we don't know how to unwind this frame. This is
* usually the case when we're trying to unwind a
* frame that was called from some assembly code
* that has no DWARF info, e.g. syscalls.
*
* b) the DEBUG info for pc is bogus. There's
* really no way to distinguish this case from the
* case above, which sucks because we could print a
* warning here.
*/
return NULL;
}
cie = dwarf_lookup_cie(fde->cie_pointer);
frame->pc = fde->initial_location;
/* CIE initial instructions */
dwarf_cfa_execute_insns(cie->initial_instructions,
cie->instructions_end, cie, fde,
frame, pc, false);
/* FDE instructions */
dwarf_cfa_execute_insns(fde->instructions, fde->end, cie,
fde, frame, pc, define_ra);
/* Calculate the CFA */
switch (frame->flags) {
case DWARF_FRAME_CFA_REG_OFFSET:
if (prev) {
BUG_ON(!prev->regs[frame->cfa_register].flags);
addr = prev->cfa;
addr += prev->regs[frame->cfa_register].addr;
frame->cfa = __raw_readl(addr);
} else {
/*
* Again, this is the first invocation of this
* recurisve function. We need to physically
* read the contents of a register in order to
* get the Canonical Frame Address for this
* function.
*/
frame->cfa = dwarf_read_arch_reg(frame->cfa_register);
}
frame->cfa += frame->cfa_offset;
break;
default:
BUG();
}
/* If we haven't seen the return address reg, we're screwed. */
BUG_ON(!frame->regs[DWARF_ARCH_RA_REG].flags);
for (i = 0; i <= frame->num_regs; i++) {
struct dwarf_reg *reg = &frame->regs[i];
if (!reg->flags)
continue;
offset = reg->addr;
offset += frame->cfa;
}
addr = frame->cfa + frame->regs[DWARF_ARCH_RA_REG].addr;
frame->return_addr = __raw_readl(addr);
frame->next = dwarf_unwind_stack(frame->return_addr, frame);
return frame;
}
static int dwarf_parse_cie(void *entry, void *p, unsigned long len,
unsigned char *end)
{
struct dwarf_cie *cie;
unsigned long flags;
int count;
cie = kzalloc(sizeof(*cie), GFP_KERNEL);
if (!cie)
return -ENOMEM;
cie->length = len;
/*
* Record the offset into the .eh_frame section
* for this CIE. It allows this CIE to be
* quickly and easily looked up from the
* corresponding FDE.
*/
cie->cie_pointer = (unsigned long)entry;
cie->version = *(char *)p++;
BUG_ON(cie->version != 1);
cie->augmentation = p;
p += strlen(cie->augmentation) + 1;
count = dwarf_read_uleb128(p, &cie->code_alignment_factor);
p += count;
count = dwarf_read_leb128(p, &cie->data_alignment_factor);
p += count;
/*
* Which column in the rule table contains the
* return address?
*/
if (cie->version == 1) {
cie->return_address_reg = __raw_readb(p);
p++;
} else {
count = dwarf_read_uleb128(p, &cie->return_address_reg);
p += count;
}
if (cie->augmentation[0] == 'z') {
unsigned int length, count;
cie->flags |= DWARF_CIE_Z_AUGMENTATION;
count = dwarf_read_uleb128(p, &length);
p += count;
BUG_ON((unsigned char *)p > end);
cie->initial_instructions = p + length;
cie->augmentation++;
}
while (*cie->augmentation) {
/*
* "L" indicates a byte showing how the
* LSDA pointer is encoded. Skip it.
*/
if (*cie->augmentation == 'L') {
p++;
cie->augmentation++;
} else if (*cie->augmentation == 'R') {
/*
* "R" indicates a byte showing
* how FDE addresses are
* encoded.
*/
cie->encoding = *(char *)p++;
cie->augmentation++;
} else if (*cie->augmentation == 'P') {
/*
* "R" indicates a personality
* routine in the CIE
* augmentation.
*/
BUG();
} else if (*cie->augmentation == 'S') {
BUG();
} else {
/*
* Unknown augmentation. Assume
* 'z' augmentation.
*/
p = cie->initial_instructions;
BUG_ON(!p);
break;
}
}
cie->initial_instructions = p;
cie->instructions_end = end;
/* Add to list */
spin_lock_irqsave(&dwarf_cie_lock, flags);
list_add_tail(&cie->link, &dwarf_cie_list);
spin_unlock_irqrestore(&dwarf_cie_lock, flags);
return 0;
}
static int dwarf_parse_fde(void *entry, u32 entry_type,
void *start, unsigned long len)
{
struct dwarf_fde *fde;
struct dwarf_cie *cie;
unsigned long flags;
int count;
void *p = start;
fde = kzalloc(sizeof(*fde), GFP_KERNEL);
if (!fde)
return -ENOMEM;
fde->length = len;
/*
* In a .eh_frame section the CIE pointer is the
* delta between the address within the FDE
*/
fde->cie_pointer = (unsigned long)(p - entry_type - 4);
cie = dwarf_lookup_cie(fde->cie_pointer);
fde->cie = cie;
if (cie->encoding)
count = dwarf_read_encoded_value(p, &fde->initial_location,
cie->encoding);
else
count = dwarf_read_addr(p, &fde->initial_location);
p += count;
if (cie->encoding)
count = dwarf_read_encoded_value(p, &fde->address_range,
cie->encoding & 0x0f);
else
count = dwarf_read_addr(p, &fde->address_range);
p += count;
if (fde->cie->flags & DWARF_CIE_Z_AUGMENTATION) {
unsigned int length;
count = dwarf_read_uleb128(p, &length);
p += count + length;
}
/* Call frame instructions. */
fde->instructions = p;
fde->end = start + len;
/* Add to list. */
spin_lock_irqsave(&dwarf_fde_lock, flags);
list_add_tail(&fde->link, &dwarf_fde_list);
spin_unlock_irqrestore(&dwarf_fde_lock, flags);
return 0;
}
static void dwarf_unwinder_dump(struct task_struct *task, struct pt_regs *regs,
unsigned long *sp,
const struct stacktrace_ops *ops, void *data)
{
struct dwarf_frame *frame;
frame = dwarf_unwind_stack(0, NULL);
while (frame && frame->return_addr) {
ops->address(data, frame->return_addr, 1);
frame = frame->next;
}
}
static struct unwinder dwarf_unwinder = {
.name = "dwarf-unwinder",
.dump = dwarf_unwinder_dump,
.rating = 150,
};
static void dwarf_unwinder_cleanup(void)
{
struct dwarf_cie *cie, *m;
struct dwarf_fde *fde, *n;
unsigned long flags;
/*
* Deallocate all the memory allocated for the DWARF unwinder.
* Traverse all the FDE/CIE lists and remove and free all the
* memory associated with those data structures.
*/
spin_lock_irqsave(&dwarf_cie_lock, flags);
list_for_each_entry_safe(cie, m, &dwarf_cie_list, link)
kfree(cie);
spin_unlock_irqrestore(&dwarf_cie_lock, flags);
spin_lock_irqsave(&dwarf_fde_lock, flags);
list_for_each_entry_safe(fde, n, &dwarf_fde_list, link)
kfree(fde);
spin_unlock_irqrestore(&dwarf_fde_lock, flags);
}
/**
* dwarf_unwinder_init - initialise the dwarf unwinder
*
* Build the data structures describing the .dwarf_frame section to
* make it easier to lookup CIE and FDE entries. Because the
* .eh_frame section is packed as tightly as possible it is not
* easy to lookup the FDE for a given PC, so we build a list of FDE
* and CIE entries that make it easier.
*/
void dwarf_unwinder_init(void)
{
u32 entry_type;
void *p, *entry;
int count, err;
unsigned long len;
unsigned int c_entries, f_entries;
unsigned char *end;
INIT_LIST_HEAD(&dwarf_cie_list);
INIT_LIST_HEAD(&dwarf_fde_list);
c_entries = 0;
f_entries = 0;
entry = &__start_eh_frame;
while ((char *)entry < __stop_eh_frame) {
p = entry;
count = dwarf_entry_len(p, &len);
if (count == 0) {
/*
* We read a bogus length field value. There is
* nothing we can do here apart from disabling
* the DWARF unwinder. We can't even skip this
* entry and move to the next one because 'len'
* tells us where our next entry is.
*/
goto out;
} else
p += count;
/* initial length does not include itself */
end = p + len;
entry_type = get_unaligned((u32 *)p);
p += 4;
if (entry_type == DW_EH_FRAME_CIE) {
err = dwarf_parse_cie(entry, p, len, end);
if (err < 0)
goto out;
else
c_entries++;
} else {
err = dwarf_parse_fde(entry, entry_type, p, len);
if (err < 0)
goto out;
else
f_entries++;
}
entry = (char *)entry + len + 4;
}
printk(KERN_INFO "DWARF unwinder initialised: read %u CIEs, %u FDEs\n",
c_entries, f_entries);
err = unwinder_register(&dwarf_unwinder);
if (err)
goto out;
return;
out:
printk(KERN_ERR "Failed to initialise DWARF unwinder: %d\n", err);
dwarf_unwinder_cleanup();
}

8
arch/sh/kernel/entry-common.S
View file

@ -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

4
arch/sh/kernel/irq.c
View file

@ -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

4
arch/sh/kernel/vmlinux.lds.S
View file

@ -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)