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kgdb, powerpc: arch specific powerpc kgdb support 

This patch removes the old kgdb reminants from ARCH=powerpc and
implements the new style arch specific stub for the common kgdb core
interface.

It is possible to have xmon and kgdb in the same kernel, but you
cannot use both at the same time because there is only one set of
debug hooks.

The arch specific kgdb implementation saves the previous state of the
debug hooks and restores them if you unconfigure the kgdb I/O driver.
Kgdb should have no impact on a kernel that has no kgdb I/O driver
configured.

Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
This commit is contained in:
Jason Wessel 2008-07-23 11:30:15 -05:00
parent 5cbad0ebf4
commit 17ce452f7e
7 changed files with 468 additions and 108 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
arch/powerpc/Kconfig
View File

@ -112,6 +112,7 @@ config PPC
select HAVE_FTRACE
select HAVE_IDE
select HAVE_KPROBES
select HAVE_ARCH_KGDB
select HAVE_KRETPROBES
select HAVE_LMB
select HAVE_DMA_ATTRS if PPC64

50
arch/powerpc/Kconfig.debug
View File

@ -41,22 +41,6 @@ config HCALL_STATS
This option will add a small amount of overhead to all hypervisor
calls.
config DEBUGGER
bool "Enable debugger hooks"
depends on DEBUG_KERNEL
help
Include in-kernel hooks for kernel debuggers. Unless you are
intending to debug the kernel, say N here.
config KGDB
bool "Include kgdb kernel debugger"
depends on DEBUGGER && (BROKEN || PPC_GEN550 || 4xx)
select DEBUG_INFO
help
Include in-kernel hooks for kgdb, the Linux kernel source level
debugger. See <http://kgdb.sourceforge.net/> for more information.
Unless you are intending to debug the kernel, say N here.
config CODE_PATCHING_SELFTEST
bool "Run self-tests of the code-patching code."
depends on DEBUG_KERNEL
@ -67,36 +51,9 @@ config FTR_FIXUP_SELFTEST
depends on DEBUG_KERNEL
default n
choice
prompt "Serial Port"
depends on KGDB
default KGDB_TTYS1
config KGDB_TTYS0
bool "ttyS0"
config KGDB_TTYS1
bool "ttyS1"
config KGDB_TTYS2
bool "ttyS2"
config KGDB_TTYS3
bool "ttyS3"
endchoice
config KGDB_CONSOLE
bool "Enable serial console thru kgdb port"
depends on KGDB && 8xx || CPM2
help
If you enable this, all serial console messages will be sent
over the gdb stub.
If unsure, say N.
config XMON
bool "Include xmon kernel debugger"
depends on DEBUGGER
depends on DEBUG_KERNEL
help
Include in-kernel hooks for the xmon kernel monitor/debugger.
Unless you are intending to debug the kernel, say N here.
@ -126,6 +83,11 @@ config XMON_DISASSEMBLY
to say Y here, unless you're building for a memory-constrained
system.
config DEBUGGER
bool
depends on KGDB || XMON
default y
config IRQSTACKS
bool "Use separate kernel stacks when processing interrupts"
help

1
arch/powerpc/kernel/Makefile
View File

@ -74,6 +74,7 @@ obj-y += time.o prom.o traps.o setup-common.o \
misc_$(CONFIG_WORD_SIZE).o
obj-$(CONFIG_PPC32) += entry_32.o setup_32.o
obj-$(CONFIG_PPC64) += dma_64.o iommu.o
obj-$(CONFIG_KGDB) += kgdb.o
obj-$(CONFIG_PPC_MULTIPLATFORM) += prom_init.o
obj-$(CONFIG_MODULES) += ppc_ksyms.o
obj-$(CONFIG_BOOTX_TEXT) += btext.o

410
arch/powerpc/kernel/kgdb.c Normal file
View File

@ -0,0 +1,410 @@
/*
* PowerPC backend to the KGDB stub.
*
* 1998 (c) Michael AK Tesch (tesch@cs.wisc.edu)
* Copyright (C) 2003 Timesys Corporation.
* Copyright (C) 2004-2006 MontaVista Software, Inc.
* PPC64 Mods (C) 2005 Frank Rowand (frowand@mvista.com)
* PPC32 support restored by Vitaly Wool <vwool@ru.mvista.com> and
* Sergei Shtylyov <sshtylyov@ru.mvista.com>
* Copyright (C) 2007-2008 Wind River Systems, Inc.
*
* This file is licensed under the terms of the GNU General Public License
* version 2. This program as licensed "as is" without any warranty of any
* kind, whether express or implied.
*/
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/kgdb.h>
#include <linux/smp.h>
#include <linux/signal.h>
#include <linux/ptrace.h>
#include <asm/current.h>
#include <asm/processor.h>
#include <asm/machdep.h>
/*
* This table contains the mapping between PowerPC hardware trap types, and
* signals, which are primarily what GDB understands. GDB and the kernel
* don't always agree on values, so we use constants taken from gdb-6.2.
*/
static struct hard_trap_info
{
unsigned int tt; /* Trap type code for powerpc */
unsigned char signo; /* Signal that we map this trap into */
} hard_trap_info[] = {
{ 0x0100, 0x02 /* SIGINT */ }, /* system reset */
{ 0x0200, 0x0b /* SIGSEGV */ }, /* machine check */
{ 0x0300, 0x0b /* SIGSEGV */ }, /* data access */
{ 0x0400, 0x0b /* SIGSEGV */ }, /* instruction access */
{ 0x0500, 0x02 /* SIGINT */ }, /* external interrupt */
{ 0x0600, 0x0a /* SIGBUS */ }, /* alignment */
{ 0x0700, 0x05 /* SIGTRAP */ }, /* program check */
{ 0x0800, 0x08 /* SIGFPE */ }, /* fp unavailable */
{ 0x0900, 0x0e /* SIGALRM */ }, /* decrementer */
{ 0x0c00, 0x14 /* SIGCHLD */ }, /* system call */
#if defined(CONFIG_40x) || defined(CONFIG_BOOKE)
{ 0x2002, 0x05 /* SIGTRAP */ }, /* debug */
#if defined(CONFIG_FSL_BOOKE)
{ 0x2010, 0x08 /* SIGFPE */ }, /* spe unavailable */
{ 0x2020, 0x08 /* SIGFPE */ }, /* spe unavailable */
{ 0x2030, 0x08 /* SIGFPE */ }, /* spe fp data */
{ 0x2040, 0x08 /* SIGFPE */ }, /* spe fp data */
{ 0x2050, 0x08 /* SIGFPE */ }, /* spe fp round */
{ 0x2060, 0x0e /* SIGILL */ }, /* performace monitor */
{ 0x2900, 0x08 /* SIGFPE */ }, /* apu unavailable */
{ 0x3100, 0x0e /* SIGALRM */ }, /* fixed interval timer */
{ 0x3200, 0x02 /* SIGINT */ }, /* watchdog */
#else /* ! CONFIG_FSL_BOOKE */
{ 0x1000, 0x0e /* SIGALRM */ }, /* prog interval timer */
{ 0x1010, 0x0e /* SIGALRM */ }, /* fixed interval timer */
{ 0x1020, 0x02 /* SIGINT */ }, /* watchdog */
{ 0x2010, 0x08 /* SIGFPE */ }, /* fp unavailable */
{ 0x2020, 0x08 /* SIGFPE */ }, /* ap unavailable */
#endif
#else /* ! (defined(CONFIG_40x) || defined(CONFIG_BOOKE)) */
{ 0x0d00, 0x05 /* SIGTRAP */ }, /* single-step */
#if defined(CONFIG_8xx)
{ 0x1000, 0x04 /* SIGILL */ }, /* software emulation */
#else /* ! CONFIG_8xx */
{ 0x0f00, 0x04 /* SIGILL */ }, /* performance monitor */
{ 0x0f20, 0x08 /* SIGFPE */ }, /* altivec unavailable */
{ 0x1300, 0x05 /* SIGTRAP */ }, /* instruction address break */
#if defined(CONFIG_PPC64)
{ 0x1200, 0x05 /* SIGILL */ }, /* system error */
{ 0x1500, 0x04 /* SIGILL */ }, /* soft patch */
{ 0x1600, 0x04 /* SIGILL */ }, /* maintenance */
{ 0x1700, 0x08 /* SIGFPE */ }, /* altivec assist */
{ 0x1800, 0x04 /* SIGILL */ }, /* thermal */
#else /* ! CONFIG_PPC64 */
{ 0x1400, 0x02 /* SIGINT */ }, /* SMI */
{ 0x1600, 0x08 /* SIGFPE */ }, /* altivec assist */
{ 0x1700, 0x04 /* SIGILL */ }, /* TAU */
{ 0x2000, 0x05 /* SIGTRAP */ }, /* run mode */
#endif
#endif
#endif
{ 0x0000, 0x00 } /* Must be last */
};
static int computeSignal(unsigned int tt)
{
struct hard_trap_info *ht;
for (ht = hard_trap_info; ht->tt && ht->signo; ht++)
if (ht->tt == tt)
return ht->signo;
return SIGHUP; /* default for things we don't know about */
}
static int kgdb_call_nmi_hook(struct pt_regs *regs)
{
kgdb_nmicallback(raw_smp_processor_id(), regs);
return 0;
}
#ifdef CONFIG_SMP
void kgdb_roundup_cpus(unsigned long flags)
{
smp_send_debugger_break(MSG_ALL_BUT_SELF);
}
#endif
/* KGDB functions to use existing PowerPC64 hooks. */
static int kgdb_debugger(struct pt_regs *regs)
{
return kgdb_handle_exception(0, computeSignal(TRAP(regs)), 0, regs);
}
static int kgdb_handle_breakpoint(struct pt_regs *regs)
{
if (user_mode(regs))
return 0;
if (kgdb_handle_exception(0, SIGTRAP, 0, regs) != 0)
return 0;
if (*(u32 *) (regs->nip) == *(u32 *) (&arch_kgdb_ops.gdb_bpt_instr))
regs->nip += 4;
return 1;
}
static int kgdb_singlestep(struct pt_regs *regs)
{
struct thread_info *thread_info, *exception_thread_info;
if (user_mode(regs))
return 0;
/*
* On Book E and perhaps other processsors, singlestep is handled on
* the critical exception stack. This causes current_thread_info()
* to fail, since it it locates the thread_info by masking off
* the low bits of the current stack pointer. We work around
* this issue by copying the thread_info from the kernel stack
* before calling kgdb_handle_exception, and copying it back
* afterwards. On most processors the copy is avoided since
* exception_thread_info == thread_info.
*/
thread_info = (struct thread_info *)(regs->gpr[1] & ~(THREAD_SIZE-1));
exception_thread_info = current_thread_info();
if (thread_info != exception_thread_info)
memcpy(exception_thread_info, thread_info, sizeof *thread_info);
kgdb_handle_exception(0, SIGTRAP, 0, regs);
if (thread_info != exception_thread_info)
memcpy(thread_info, exception_thread_info, sizeof *thread_info);
return 1;
}
static int kgdb_iabr_match(struct pt_regs *regs)
{
if (user_mode(regs))
return 0;
if (kgdb_handle_exception(0, computeSignal(TRAP(regs)), 0, regs) != 0)
return 0;
return 1;
}
static int kgdb_dabr_match(struct pt_regs *regs)
{
if (user_mode(regs))
return 0;
if (kgdb_handle_exception(0, computeSignal(TRAP(regs)), 0, regs) != 0)
return 0;
return 1;
}
#define PACK64(ptr, src) do { *(ptr++) = (src); } while (0)
#define PACK32(ptr, src) do { \
u32 *ptr32; \
ptr32 = (u32 *)ptr; \
*(ptr32++) = (src); \
ptr = (unsigned long *)ptr32; \
} while (0)
void pt_regs_to_gdb_regs(unsigned long *gdb_regs, struct pt_regs *regs)
{
unsigned long *ptr = gdb_regs;
int reg;
memset(gdb_regs, 0, NUMREGBYTES);
for (reg = 0; reg < 32; reg++)
PACK64(ptr, regs->gpr[reg]);
#ifdef CONFIG_FSL_BOOKE
#ifdef CONFIG_SPE
for (reg = 0; reg < 32; reg++)
PACK64(ptr, current->thread.evr[reg]);
#else
ptr += 32;
#endif
#else
/* fp registers not used by kernel, leave zero */
ptr += 32 * 8 / sizeof(long);
#endif
PACK64(ptr, regs->nip);
PACK64(ptr, regs->msr);
PACK32(ptr, regs->ccr);
PACK64(ptr, regs->link);
PACK64(ptr, regs->ctr);
PACK32(ptr, regs->xer);
BUG_ON((unsigned long)ptr >
(unsigned long)(((void *)gdb_regs) + NUMREGBYTES));
}
void sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *p)
{
struct pt_regs *regs = (struct pt_regs *)(p->thread.ksp +
STACK_FRAME_OVERHEAD);
unsigned long *ptr = gdb_regs;
int reg;
memset(gdb_regs, 0, NUMREGBYTES);
/* Regs GPR0-2 */
for (reg = 0; reg < 3; reg++)
PACK64(ptr, regs->gpr[reg]);
/* Regs GPR3-13 are caller saved, not in regs->gpr[] */
ptr += 11;
/* Regs GPR14-31 */
for (reg = 14; reg < 32; reg++)
PACK64(ptr, regs->gpr[reg]);
#ifdef CONFIG_FSL_BOOKE
#ifdef CONFIG_SPE
for (reg = 0; reg < 32; reg++)
PACK64(ptr, p->thread.evr[reg]);
#else
ptr += 32;
#endif
#else
/* fp registers not used by kernel, leave zero */
ptr += 32 * 8 / sizeof(long);
#endif
PACK64(ptr, regs->nip);
PACK64(ptr, regs->msr);
PACK32(ptr, regs->ccr);
PACK64(ptr, regs->link);
PACK64(ptr, regs->ctr);
PACK32(ptr, regs->xer);
BUG_ON((unsigned long)ptr >
(unsigned long)(((void *)gdb_regs) + NUMREGBYTES));
}
#define UNPACK64(dest, ptr) do { dest = *(ptr++); } while (0)
#define UNPACK32(dest, ptr) do { \
u32 *ptr32; \
ptr32 = (u32 *)ptr; \
dest = *(ptr32++); \
ptr = (unsigned long *)ptr32; \
} while (0)
void gdb_regs_to_pt_regs(unsigned long *gdb_regs, struct pt_regs *regs)
{
unsigned long *ptr = gdb_regs;
int reg;
#ifdef CONFIG_SPE
union {
u32 v32[2];
u64 v64;
} acc;
#endif
for (reg = 0; reg < 32; reg++)
UNPACK64(regs->gpr[reg], ptr);
#ifdef CONFIG_FSL_BOOKE
#ifdef CONFIG_SPE
for (reg = 0; reg < 32; reg++)
UNPACK64(current->thread.evr[reg], ptr);
#else
ptr += 32;
#endif
#else
/* fp registers not used by kernel, leave zero */
ptr += 32 * 8 / sizeof(int);
#endif
UNPACK64(regs->nip, ptr);
UNPACK64(regs->msr, ptr);
UNPACK32(regs->ccr, ptr);
UNPACK64(regs->link, ptr);
UNPACK64(regs->ctr, ptr);
UNPACK32(regs->xer, ptr);
BUG_ON((unsigned long)ptr >
(unsigned long)(((void *)gdb_regs) + NUMREGBYTES));
}
/*
* This function does PowerPC specific procesing for interfacing to gdb.
*/
int kgdb_arch_handle_exception(int vector, int signo, int err_code,
char *remcom_in_buffer, char *remcom_out_buffer,
struct pt_regs *linux_regs)
{
char *ptr = &remcom_in_buffer[1];
unsigned long addr;
switch (remcom_in_buffer[0]) {
/*
* sAA..AA Step one instruction from AA..AA
* This will return an error to gdb ..
*/
case 's':
case 'c':
/* handle the optional parameter */
if (kgdb_hex2long(&ptr, &addr))
linux_regs->nip = addr;
atomic_set(&kgdb_cpu_doing_single_step, -1);
/* set the trace bit if we're stepping */
if (remcom_in_buffer[0] == 's') {
#if defined(CONFIG_40x) || defined(CONFIG_BOOKE)
mtspr(SPRN_DBCR0,
mfspr(SPRN_DBCR0) | DBCR0_IC | DBCR0_IDM);
linux_regs->msr |= MSR_DE;
#else
linux_regs->msr |= MSR_SE;
#endif
kgdb_single_step = 1;
if (kgdb_contthread)
atomic_set(&kgdb_cpu_doing_single_step,
raw_smp_processor_id());
}
return 0;
}
return -1;
}
/*
* Global data
*/
struct kgdb_arch arch_kgdb_ops = {
.gdb_bpt_instr = {0x7d, 0x82, 0x10, 0x08},
};
static int kgdb_not_implemented(struct pt_regs *regs)
{
return 0;
}
static void *old__debugger_ipi;
static void *old__debugger;
static void *old__debugger_bpt;
static void *old__debugger_sstep;
static void *old__debugger_iabr_match;
static void *old__debugger_dabr_match;
static void *old__debugger_fault_handler;
int kgdb_arch_init(void)
{
old__debugger_ipi = __debugger_ipi;
old__debugger = __debugger;
old__debugger_bpt = __debugger_bpt;
old__debugger_sstep = __debugger_sstep;
old__debugger_iabr_match = __debugger_iabr_match;
old__debugger_dabr_match = __debugger_dabr_match;
old__debugger_fault_handler = __debugger_fault_handler;
__debugger_ipi = kgdb_call_nmi_hook;
__debugger = kgdb_debugger;
__debugger_bpt = kgdb_handle_breakpoint;
__debugger_sstep = kgdb_singlestep;
__debugger_iabr_match = kgdb_iabr_match;
__debugger_dabr_match = kgdb_dabr_match;
__debugger_fault_handler = kgdb_not_implemented;
return 0;
}
void kgdb_arch_exit(void)
{
__debugger_ipi = old__debugger_ipi;
__debugger = old__debugger;
__debugger_bpt = old__debugger_bpt;
__debugger_sstep = old__debugger_sstep;
__debugger_iabr_match = old__debugger_iabr_match;
__debugger_dabr_match = old__debugger_dabr_match;
__debugger_fault_handler = old__debugger_fault_handler;
}

16
arch/powerpc/kernel/setup_32.c
View File

@ -43,10 +43,6 @@
#define DBG(fmt...)
#if defined CONFIG_KGDB
#include <asm/kgdb.h>
#endif
extern void bootx_init(unsigned long r4, unsigned long phys);
int boot_cpuid;
@ -302,18 +298,6 @@ void __init setup_arch(char **cmdline_p)
xmon_setup();
#if defined(CONFIG_KGDB)
if (ppc_md.kgdb_map_scc)
ppc_md.kgdb_map_scc();
set_debug_traps();
if (strstr(cmd_line, "gdb")) {
if (ppc_md.progress)
ppc_md.progress("setup_arch: kgdb breakpoint", 0x4000);
printk("kgdb breakpoint activated\n");
breakpoint();
}
#endif
/*
* Set cache line size based on type of cpu as a default.
* Systems with OF can look in the properties on the cpu node(s)

6
arch/powerpc/platforms/powermac/setup.c
View File

@ -97,8 +97,6 @@ extern struct machdep_calls pmac_md;
int sccdbg;
#endif
extern void zs_kgdb_hook(int tty_num);
sys_ctrler_t sys_ctrler = SYS_CTRLER_UNKNOWN;
EXPORT_SYMBOL(sys_ctrler);
@ -329,10 +327,6 @@ static void __init pmac_setup_arch(void)
l2cr_init();
#endif /* CONFIG_PPC32 */
#ifdef CONFIG_KGDB
zs_kgdb_hook(0);
#endif
find_via_cuda();
find_via_pmu();
smu_init();

92
include/asm-powerpc/kgdb.h
View File

@ -1,57 +1,65 @@
/*
* kgdb.h: Defines and declarations for serial line source level
* remote debugging of the Linux kernel using gdb.
* include/asm-powerpc/kgdb.h
*
* The PowerPC (32/64) specific defines / externs for KGDB. Based on
* the previous 32bit and 64bit specific files, which had the following
* copyrights:
*
* PPC64 Mods (C) 2005 Frank Rowand (frowand@mvista.com)
* PPC Mods (C) 2004 Tom Rini (trini@mvista.com)
* PPC Mods (C) 2003 John Whitney (john.whitney@timesys.com)
* PPC Mods (C) 1998 Michael Tesch (tesch@cs.wisc.edu)
*
*
* Copyright (C) 1995 David S. Miller (davem@caip.rutgers.edu)
* Author: Tom Rini <trini@kernel.crashing.org>
*
* 2006 (c) MontaVista Software, Inc. This file is licensed under
* the terms of the GNU General Public License version 2. This program
* is licensed "as is" without any warranty of any kind, whether express
* or implied.
*/
#ifdef __KERNEL__
#ifndef _PPC_KGDB_H
#define _PPC_KGDB_H
#ifndef __POWERPC_KGDB_H__
#define __POWERPC_KGDB_H__
#ifndef __ASSEMBLY__
/* Things specific to the gen550 backend. */
struct uart_port;
extern void gen550_progress(char *, unsigned short);
extern void gen550_kgdb_map_scc(void);
extern void gen550_init(int, struct uart_port *);
/* Things specific to the pmac backend. */
extern void zs_kgdb_hook(int tty_num);
/* To init the kgdb engine. (called by serial hook)*/
extern void set_debug_traps(void);
/* To enter the debugger explicitly. */
extern void breakpoint(void);
/* For taking exceptions
* these are defined in traps.c
*/
extern int (*debugger)(struct pt_regs *regs);
extern int (*debugger_bpt)(struct pt_regs *regs);
extern int (*debugger_sstep)(struct pt_regs *regs);
extern int (*debugger_iabr_match)(struct pt_regs *regs);
extern int (*debugger_dabr_match)(struct pt_regs *regs);
extern void (*debugger_fault_handler)(struct pt_regs *regs);
/* What we bring to the party */
int kgdb_bpt(struct pt_regs *regs);
int kgdb_sstep(struct pt_regs *regs);
void kgdb(struct pt_regs *regs);
int kgdb_iabr_match(struct pt_regs *regs);
int kgdb_dabr_match(struct pt_regs *regs);
#define BREAK_INSTR_SIZE 4
#define BUFMAX ((NUMREGBYTES * 2) + 512)
#define OUTBUFMAX ((NUMREGBYTES * 2) + 512)
static inline void arch_kgdb_breakpoint(void)
{
asm(".long 0x7d821008"); /* twge r2, r2 */
}
#define CACHE_FLUSH_IS_SAFE 1
/* The number bytes of registers we have to save depends on a few
* things. For 64bit we default to not including vector registers and
* vector state registers. */
#ifdef CONFIG_PPC64
/*
* external low-level support routines (ie macserial.c)
* 64 bit (8 byte) registers:
* 32 gpr, 32 fpr, nip, msr, link, ctr
* 32 bit (4 byte) registers:
* ccr, xer, fpscr
*/
extern void kgdb_interruptible(int); /* control interrupts from serial */
extern void putDebugChar(char); /* write a single character */
extern char getDebugChar(void); /* read and return a single char */
#define NUMREGBYTES ((68 * 8) + (3 * 4))
#define NUMCRITREGBYTES 184
#else /* CONFIG_PPC32 */
/* On non-E500 family PPC32 we determine the size by picking the last
* register we need, but on E500 we skip sections so we list what we
* need to store, and add it up. */
#ifndef CONFIG_E500
#define MAXREG (PT_FPSCR+1)
#else
/* 32 GPRs (8 bytes), nip, msr, ccr, link, ctr, xer, acc (8 bytes), spefscr*/
#define MAXREG ((32*2)+6+2+1)
#endif
#define NUMREGBYTES (MAXREG * sizeof(int))
/* CR/LR, R1, R2, R13-R31 inclusive. */
#define NUMCRITREGBYTES (23 * sizeof(int))
#endif /* 32/64 */
#endif /* !(__ASSEMBLY__) */
#endif /* !(_PPC_KGDB_H) */
#endif /* !__POWERPC_KGDB_H__ */
#endif /* __KERNEL__ */