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Merge remote-tracking branch 'lsk/v3.10/topic/arm64-kgdb' into lsk-v3.10-arm64-misc

Browse Source 
Conflicts:
	arch/arm64/include/asm/debug-monitors.h
	arch/arm64/kernel/debug-monitors.c
This commit is contained in:
Mark Brown
2014-05-21 18:39:39 +01:00
parent 8a411cf1c2 9da2fb2070
commit 7b1f792f1f
9 changed files with 611 additions and 19 deletions
Download Patch File Download Diff File Expand all files Collapse all files

1
arch/arm64/Kconfig
View File

@@ -21,6 +21,7 @@ config ARM64
select GENERIC_STRNLEN_USER
select GENERIC_TIME_VSYSCALL
select HARDIRQS_SW_RESEND
select HAVE_ARCH_KGDB
select HAVE_ARCH_TRACEHOOK
select HAVE_DEBUG_BUGVERBOSE
select HAVE_DEBUG_KMEMLEAK

92
arch/arm64/include/asm/debug-monitors.h
View File

@@ -26,6 +26,53 @@
#define DBG_ESR_EVT_HWWP 0x2
#define DBG_ESR_EVT_BRK 0x6
/*
* Break point instruction encoding
*/
#define BREAK_INSTR_SIZE 4
/*
* ESR values expected for dynamic and compile time BRK instruction
*/
#define DBG_ESR_VAL_BRK(x) (0xf2000000 | ((x) & 0xfffff))
/*
* #imm16 values used for BRK instruction generation
* Allowed values for kgbd are 0x400 - 0x7ff
* 0x400: for dynamic BRK instruction
* 0x401: for compile time BRK instruction
*/
#define KGDB_DYN_DGB_BRK_IMM 0x400
#define KDBG_COMPILED_DBG_BRK_IMM 0x401
/*
* BRK instruction encoding
* The #imm16 value should be placed at bits[20:5] within BRK ins
*/
#define AARCH64_BREAK_MON 0xd4200000
/*
* Extract byte from BRK instruction
*/
#define KGDB_DYN_DGB_BRK_INS_BYTE(x) \
((((AARCH64_BREAK_MON) & 0xffe0001f) >> (x * 8)) & 0xff)
/*
* Extract byte from BRK #imm16
*/
#define KGBD_DYN_DGB_BRK_IMM_BYTE(x) \
(((((KGDB_DYN_DGB_BRK_IMM) & 0xffff) << 5) >> (x * 8)) & 0xff)
#define KGDB_DYN_DGB_BRK_BYTE(x) \
(KGDB_DYN_DGB_BRK_INS_BYTE(x) | KGBD_DYN_DGB_BRK_IMM_BYTE(x))
#define KGDB_DYN_BRK_INS_BYTE0 KGDB_DYN_DGB_BRK_BYTE(0)
#define KGDB_DYN_BRK_INS_BYTE1 KGDB_DYN_DGB_BRK_BYTE(1)
#define KGDB_DYN_BRK_INS_BYTE2 KGDB_DYN_DGB_BRK_BYTE(2)
#define KGDB_DYN_BRK_INS_BYTE3 KGDB_DYN_DGB_BRK_BYTE(3)
#define CACHE_FLUSH_IS_SAFE 1
enum debug_el {
DBG_ACTIVE_EL0 = 0,
DBG_ACTIVE_EL1,
@@ -43,25 +90,29 @@ enum debug_el {
#ifndef __ASSEMBLY__
struct task_struct;
#define local_dbg_save(flags) \
do { \
typecheck(unsigned long, flags); \
asm volatile( \
"mrs %0, daif // local_dbg_save\n" \
"msr daifset, #8" \
: "=r" (flags) : : "memory"); \
} while (0)
#define local_dbg_restore(flags) \
do { \
typecheck(unsigned long, flags); \
asm volatile( \
"msr daif, %0 // local_dbg_restore\n" \
: : "r" (flags) : "memory"); \
} while (0)
#define DBG_ARCH_ID_RESERVED 0 /* In case of ptrace ABI updates. */
#define DBG_HOOK_HANDLED 0
#define DBG_HOOK_ERROR 1
struct step_hook {
struct list_head node;
int (*fn)(struct pt_regs *regs, unsigned int esr);
};
void register_step_hook(struct step_hook *hook);
void unregister_step_hook(struct step_hook *hook);
struct break_hook {
struct list_head node;
u32 esr_val;
u32 esr_mask;
int (*fn)(struct pt_regs *regs, unsigned int esr);
};
void register_break_hook(struct break_hook *hook);
void unregister_break_hook(struct break_hook *hook);
u8 debug_monitors_arch(void);
void enable_debug_monitors(enum debug_el el);
@@ -83,7 +134,14 @@ static inline int reinstall_suspended_bps(struct pt_regs *regs)
}
#endif
#ifdef CONFIG_COMPAT
int aarch32_break_handler(struct pt_regs *regs);
#else
static int aarch32_break_handler(struct pt_regs *regs)
{
return -EFAULT;
}
#endif
#endif /* __ASSEMBLY */
#endif /* __KERNEL__ */

23
arch/arm64/include/asm/irqflags.h
View File

@@ -87,5 +87,28 @@ static inline int arch_irqs_disabled_flags(unsigned long flags)
return flags & PSR_I_BIT;
}
/*
* save and restore debug state
*/
#define local_dbg_save(flags) \
do { \
typecheck(unsigned long, flags); \
asm volatile( \
"mrs %0, daif // local_dbg_save\n" \
"msr daifset, #8" \
: "=r" (flags) : : "memory"); \
} while (0)
#define local_dbg_restore(flags) \
do { \
typecheck(unsigned long, flags); \
asm volatile( \
"msr daif, %0 // local_dbg_restore\n" \
: : "r" (flags) : "memory"); \
} while (0)
#define local_dbg_enable() asm("msr daifclr, #8" : : : "memory")
#define local_dbg_disable() asm("msr daifset, #8" : : : "memory")
#endif
#endif

84
arch/arm64/include/asm/kgdb.h Normal file
View File

@@ -0,0 +1,84 @@
/*
* AArch64 KGDB support
*
* Based on arch/arm/include/kgdb.h
*
* Copyright (C) 2013 Cavium Inc.
* Author: Vijaya Kumar K <vijaya.kumar@caviumnetworks.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* 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, see <http://www.gnu.org/licenses/>.
*/
#ifndef __ARM_KGDB_H
#define __ARM_KGDB_H
#include <linux/ptrace.h>
#include <asm/debug-monitors.h>
#ifndef __ASSEMBLY__
static inline void arch_kgdb_breakpoint(void)
{
asm ("brk %0" : : "I" (KDBG_COMPILED_DBG_BRK_IMM));
}
extern void kgdb_handle_bus_error(void);
extern int kgdb_fault_expected;
#endif /* !__ASSEMBLY__ */
/*
* gdb is expecting the following registers layout.
*
* General purpose regs:
* r0-r30: 64 bit
* sp,pc : 64 bit
* pstate : 64 bit
* Total: 34
* FPU regs:
* f0-f31: 128 bit
* Total: 32
* Extra regs
* fpsr & fpcr: 32 bit
* Total: 2
*
*/
#define _GP_REGS 34
#define _FP_REGS 32
#define _EXTRA_REGS 2
/*
* general purpose registers size in bytes.
* pstate is only 4 bytes. subtract 4 bytes
*/
#define GP_REG_BYTES (_GP_REGS * 8)
#define DBG_MAX_REG_NUM (_GP_REGS + _FP_REGS + _EXTRA_REGS)
/*
* Size of I/O buffer for gdb packet.
* considering to hold all register contents, size is set
*/
#define BUFMAX 2048
/*
* Number of bytes required for gdb_regs buffer.
* _GP_REGS: 8 bytes, _FP_REGS: 16 bytes and _EXTRA_REGS: 4 bytes each
* GDB fails to connect for size beyond this with error
* "'g' packet reply is too long"
*/
#define NUMREGBYTES ((_GP_REGS * 8) + (_FP_REGS * 16) + \
(_EXTRA_REGS * 4))
#endif /* __ASM_KGDB_H */

2
arch/arm64/include/asm/ptrace.h
View File

@@ -163,7 +163,7 @@ static inline int valid_user_regs(struct user_pt_regs *regs)
return 0;
}
#define instruction_pointer(regs) (regs)->pc
#define instruction_pointer(regs) ((unsigned long)(regs)->pc)
#ifdef CONFIG_SMP
extern unsigned long profile_pc(struct pt_regs *regs);

1
arch/arm64/kernel/Makefile
View File

@@ -18,6 +18,7 @@ arm64-obj-$(CONFIG_SMP) += smp.o smp_spin_table.o
arm64-obj-$(CONFIG_HW_PERF_EVENTS) += perf_event.o
arm64-obj-$(CONFIG_HAVE_HW_BREAKPOINT)+= hw_breakpoint.o
arm64-obj-$(CONFIG_EARLY_PRINTK) += early_printk.o
arm64-obj-$(CONFIG_KGDB) += kgdb.o
obj-y += $(arm64-obj-y) vdso/
obj-m += $(arm64-obj-m)

89
arch/arm64/kernel/debug-monitors.c
View File

@@ -139,6 +139,7 @@ static void clear_os_lock(void *unused)
{
asm volatile("msr oslar_el1, %0" : : "r" (0));
isb();
local_dbg_enable();
}
static int __cpuinit os_lock_notify(struct notifier_block *self,
@@ -188,6 +189,48 @@ static void clear_regs_spsr_ss(struct pt_regs *regs)
regs->pstate = spsr;
}
/* EL1 Single Step Handler hooks */
static LIST_HEAD(step_hook);
DEFINE_RWLOCK(step_hook_lock);
void register_step_hook(struct step_hook *hook)
{
write_lock(&step_hook_lock);
list_add(&hook->node, &step_hook);
write_unlock(&step_hook_lock);
}
void unregister_step_hook(struct step_hook *hook)
{
write_lock(&step_hook_lock);
list_del(&hook->node);
write_unlock(&step_hook_lock);
}
/*
* Call registered single step handers
* There is no Syndrome info to check for determining the handler.
* So we call all the registered handlers, until the right handler is
* found which returns zero.
*/
static int call_step_hook(struct pt_regs *regs, unsigned int esr)
{
struct step_hook *hook;
int retval = DBG_HOOK_ERROR;
read_lock(&step_hook_lock);
list_for_each_entry(hook, &step_hook, node) {
retval = hook->fn(regs, esr);
if (retval == DBG_HOOK_HANDLED)
break;
}
read_unlock(&step_hook_lock);
return retval;
}
static int single_step_handler(unsigned long addr, unsigned int esr,
struct pt_regs *regs)
{
@@ -215,7 +258,9 @@ static int single_step_handler(unsigned long addr, unsigned int esr,
*/
user_rewind_single_step(current);
} else {
/* TODO: route to KGDB */
if (call_step_hook(regs, esr) == DBG_HOOK_HANDLED)
return 0;
pr_warning("Unexpected kernel single-step exception at EL1\n");
/*
* Re-enable stepping since we know that we will be
@@ -227,11 +272,53 @@ static int single_step_handler(unsigned long addr, unsigned int esr,
return 0;
}
/*
* Breakpoint handler is re-entrant as another breakpoint can
* hit within breakpoint handler, especically in kprobes.
* Use reader/writer locks instead of plain spinlock.
*/
static LIST_HEAD(break_hook);
DEFINE_RWLOCK(break_hook_lock);
void register_break_hook(struct break_hook *hook)
{
write_lock(&break_hook_lock);
list_add(&hook->node, &break_hook);
write_unlock(&break_hook_lock);
}
void unregister_break_hook(struct break_hook *hook)
{
write_lock(&break_hook_lock);
list_del(&hook->node);
write_unlock(&break_hook_lock);
}
static int call_break_hook(struct pt_regs *regs, unsigned int esr)
{
struct break_hook *hook;
int (*fn)(struct pt_regs *regs, unsigned int esr) = NULL;
read_lock(&break_hook_lock);
list_for_each_entry(hook, &break_hook, node)
if ((esr & hook->esr_mask) == hook->esr_val)
fn = hook->fn;
read_unlock(&break_hook_lock);
return fn ? fn(regs, esr) : DBG_HOOK_ERROR;
}
static int brk_handler(unsigned long addr, unsigned int esr,
struct pt_regs *regs)
{
siginfo_t info;
if (call_break_hook(regs, esr) == DBG_HOOK_HANDLED)
return 0;
pr_warn("unexpected brk exception at %lx, esr=0x%x\n",
(long)instruction_pointer(regs), esr);
if (!user_mode(regs))
return -EFAULT;

2
arch/arm64/kernel/entry.S
View File

@@ -288,6 +288,8 @@ el1_dbg:
/*
* Debug exception handling
*/
cmp x24, #ESR_EL1_EC_BRK64 // if BRK64
cinc x24, x24, eq // set bit '0'
tbz x24, #0, el1_inv // EL1 only
mrs x0, far_el1
mov x2, sp // struct pt_regs

336
arch/arm64/kernel/kgdb.c Normal file
View File

@@ -0,0 +1,336 @@
/*
* AArch64 KGDB support
*
* Based on arch/arm/kernel/kgdb.c
*
* Copyright (C) 2013 Cavium Inc.
* Author: Vijaya Kumar K <vijaya.kumar@caviumnetworks.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* 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, see <http://www.gnu.org/licenses/>.
*/
#include <linux/irq.h>
#include <linux/kdebug.h>
#include <linux/kgdb.h>
#include <asm/traps.h>
struct dbg_reg_def_t dbg_reg_def[DBG_MAX_REG_NUM] = {
{ "x0", 8, offsetof(struct pt_regs, regs[0])},
{ "x1", 8, offsetof(struct pt_regs, regs[1])},
{ "x2", 8, offsetof(struct pt_regs, regs[2])},
{ "x3", 8, offsetof(struct pt_regs, regs[3])},
{ "x4", 8, offsetof(struct pt_regs, regs[4])},
{ "x5", 8, offsetof(struct pt_regs, regs[5])},
{ "x6", 8, offsetof(struct pt_regs, regs[6])},
{ "x7", 8, offsetof(struct pt_regs, regs[7])},
{ "x8", 8, offsetof(struct pt_regs, regs[8])},
{ "x9", 8, offsetof(struct pt_regs, regs[9])},
{ "x10", 8, offsetof(struct pt_regs, regs[10])},
{ "x11", 8, offsetof(struct pt_regs, regs[11])},
{ "x12", 8, offsetof(struct pt_regs, regs[12])},
{ "x13", 8, offsetof(struct pt_regs, regs[13])},
{ "x14", 8, offsetof(struct pt_regs, regs[14])},
{ "x15", 8, offsetof(struct pt_regs, regs[15])},
{ "x16", 8, offsetof(struct pt_regs, regs[16])},
{ "x17", 8, offsetof(struct pt_regs, regs[17])},
{ "x18", 8, offsetof(struct pt_regs, regs[18])},
{ "x19", 8, offsetof(struct pt_regs, regs[19])},
{ "x20", 8, offsetof(struct pt_regs, regs[20])},
{ "x21", 8, offsetof(struct pt_regs, regs[21])},
{ "x22", 8, offsetof(struct pt_regs, regs[22])},
{ "x23", 8, offsetof(struct pt_regs, regs[23])},
{ "x24", 8, offsetof(struct pt_regs, regs[24])},
{ "x25", 8, offsetof(struct pt_regs, regs[25])},
{ "x26", 8, offsetof(struct pt_regs, regs[26])},
{ "x27", 8, offsetof(struct pt_regs, regs[27])},
{ "x28", 8, offsetof(struct pt_regs, regs[28])},
{ "x29", 8, offsetof(struct pt_regs, regs[29])},
{ "x30", 8, offsetof(struct pt_regs, regs[30])},
{ "sp", 8, offsetof(struct pt_regs, sp)},
{ "pc", 8, offsetof(struct pt_regs, pc)},
{ "pstate", 8, offsetof(struct pt_regs, pstate)},
{ "v0", 16, -1 },
{ "v1", 16, -1 },
{ "v2", 16, -1 },
{ "v3", 16, -1 },
{ "v4", 16, -1 },
{ "v5", 16, -1 },
{ "v6", 16, -1 },
{ "v7", 16, -1 },
{ "v8", 16, -1 },
{ "v9", 16, -1 },
{ "v10", 16, -1 },
{ "v11", 16, -1 },
{ "v12", 16, -1 },
{ "v13", 16, -1 },
{ "v14", 16, -1 },
{ "v15", 16, -1 },
{ "v16", 16, -1 },
{ "v17", 16, -1 },
{ "v18", 16, -1 },
{ "v19", 16, -1 },
{ "v20", 16, -1 },
{ "v21", 16, -1 },
{ "v22", 16, -1 },
{ "v23", 16, -1 },
{ "v24", 16, -1 },
{ "v25", 16, -1 },
{ "v26", 16, -1 },
{ "v27", 16, -1 },
{ "v28", 16, -1 },
{ "v29", 16, -1 },
{ "v30", 16, -1 },
{ "v31", 16, -1 },
{ "fpsr", 4, -1 },
{ "fpcr", 4, -1 },
};
char *dbg_get_reg(int regno, void *mem, struct pt_regs *regs)
{
if (regno >= DBG_MAX_REG_NUM || regno < 0)
return NULL;
if (dbg_reg_def[regno].offset != -1)
memcpy(mem, (void *)regs + dbg_reg_def[regno].offset,
dbg_reg_def[regno].size);
else
memset(mem, 0, dbg_reg_def[regno].size);
return dbg_reg_def[regno].name;
}
int dbg_set_reg(int regno, void *mem, struct pt_regs *regs)
{
if (regno >= DBG_MAX_REG_NUM || regno < 0)
return -EINVAL;
if (dbg_reg_def[regno].offset != -1)
memcpy((void *)regs + dbg_reg_def[regno].offset, mem,
dbg_reg_def[regno].size);
return 0;
}
void
sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *task)
{
struct pt_regs *thread_regs;
/* Initialize to zero */
memset((char *)gdb_regs, 0, NUMREGBYTES);
thread_regs = task_pt_regs(task);
memcpy((void *)gdb_regs, (void *)thread_regs->regs, GP_REG_BYTES);
}
void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long pc)
{
regs->pc = pc;
}
static int compiled_break;
static void kgdb_arch_update_addr(struct pt_regs *regs,
char *remcom_in_buffer)
{
unsigned long addr;
char *ptr;
ptr = &remcom_in_buffer[1];
if (kgdb_hex2long(&ptr, &addr))
kgdb_arch_set_pc(regs, addr);
else if (compiled_break == 1)
kgdb_arch_set_pc(regs, regs->pc + 4);
compiled_break = 0;
}
int kgdb_arch_handle_exception(int exception_vector, int signo,
int err_code, char *remcom_in_buffer,
char *remcom_out_buffer,
struct pt_regs *linux_regs)
{
int err;
switch (remcom_in_buffer[0]) {
case 'D':
case 'k':
/*
* Packet D (Detach), k (kill). No special handling
* is required here. Handle same as c packet.
*/
case 'c':
/*
* Packet c (Continue) to continue executing.
* Set pc to required address.
* Try to read optional parameter and set pc.
* If this was a compiled breakpoint, we need to move
* to the next instruction else we will just breakpoint
* over and over again.
*/
kgdb_arch_update_addr(linux_regs, remcom_in_buffer);
atomic_set(&kgdb_cpu_doing_single_step, -1);
kgdb_single_step = 0;
/*
* Received continue command, disable single step
*/
if (kernel_active_single_step())
kernel_disable_single_step();
err = 0;
break;
case 's':
/*
* Update step address value with address passed
* with step packet.
* On debug exception return PC is copied to ELR
* So just update PC.
* If no step address is passed, resume from the address
* pointed by PC. Do not update PC
*/
kgdb_arch_update_addr(linux_regs, remcom_in_buffer);
atomic_set(&kgdb_cpu_doing_single_step, raw_smp_processor_id());
kgdb_single_step = 1;
/*
* Enable single step handling
*/
if (!kernel_active_single_step())
kernel_enable_single_step(linux_regs);
err = 0;
break;
default:
err = -1;
}
return err;
}
static int kgdb_brk_fn(struct pt_regs *regs, unsigned int esr)
{
kgdb_handle_exception(1, SIGTRAP, 0, regs);
return 0;
}
static int kgdb_compiled_brk_fn(struct pt_regs *regs, unsigned int esr)
{
compiled_break = 1;
kgdb_handle_exception(1, SIGTRAP, 0, regs);
return 0;
}
static int kgdb_step_brk_fn(struct pt_regs *regs, unsigned int esr)
{
kgdb_handle_exception(1, SIGTRAP, 0, regs);
return 0;
}
static struct break_hook kgdb_brkpt_hook = {
.esr_mask = 0xffffffff,
.esr_val = DBG_ESR_VAL_BRK(KGDB_DYN_DGB_BRK_IMM),
.fn = kgdb_brk_fn
};
static struct break_hook kgdb_compiled_brkpt_hook = {
.esr_mask = 0xffffffff,
.esr_val = DBG_ESR_VAL_BRK(KDBG_COMPILED_DBG_BRK_IMM),
.fn = kgdb_compiled_brk_fn
};
static struct step_hook kgdb_step_hook = {
.fn = kgdb_step_brk_fn
};
static void kgdb_call_nmi_hook(void *ignored)
{
kgdb_nmicallback(raw_smp_processor_id(), get_irq_regs());
}
void kgdb_roundup_cpus(unsigned long flags)
{
local_irq_enable();
smp_call_function(kgdb_call_nmi_hook, NULL, 0);
local_irq_disable();
}
static int __kgdb_notify(struct die_args *args, unsigned long cmd)
{
struct pt_regs *regs = args->regs;
if (kgdb_handle_exception(1, args->signr, cmd, regs))
return NOTIFY_DONE;
return NOTIFY_STOP;
}
static int
kgdb_notify(struct notifier_block *self, unsigned long cmd, void *ptr)
{
unsigned long flags;
int ret;
local_irq_save(flags);
ret = __kgdb_notify(ptr, cmd);
local_irq_restore(flags);
return ret;
}
static struct notifier_block kgdb_notifier = {
.notifier_call = kgdb_notify,
/*
* Want to be lowest priority
*/
.priority = -INT_MAX,
};
/*
* kgdb_arch_init - Perform any architecture specific initalization.
* This function will handle the initalization of any architecture
* specific callbacks.
*/
int kgdb_arch_init(void)
{
int ret = register_die_notifier(&kgdb_notifier);
if (ret != 0)
return ret;
register_break_hook(&kgdb_brkpt_hook);
register_break_hook(&kgdb_compiled_brkpt_hook);
register_step_hook(&kgdb_step_hook);
return 0;
}
/*
* kgdb_arch_exit - Perform any architecture specific uninitalization.
* This function will handle the uninitalization of any architecture
* specific callbacks, for dynamic registration and unregistration.
*/
void kgdb_arch_exit(void)
{
unregister_break_hook(&kgdb_brkpt_hook);
unregister_break_hook(&kgdb_compiled_brkpt_hook);
unregister_step_hook(&kgdb_step_hook);
unregister_die_notifier(&kgdb_notifier);
}
/*
* ARM instructions are always in LE.
* Break instruction is encoded in LE format
*/
struct kgdb_arch arch_kgdb_ops = {
.gdb_bpt_instr = {
KGDB_DYN_BRK_INS_BYTE0,
KGDB_DYN_BRK_INS_BYTE1,
KGDB_DYN_BRK_INS_BYTE2,
KGDB_DYN_BRK_INS_BYTE3,
}
};