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linux/arch/arm64/kernel/kgdb.c
Dave P Martin c696b93461 arm64/debug: Simplify BRK insn opcode declarations 
The way the KGDB_DYN_BRK_INS_BYTEx macros are declared is more
complex than it needs to be.  Also, the macros are only used in one
place, which is arch-specific anyway.

This patch refactors the macros to simplify them, and exposes an
argument so that we can have a single macro instead of 4.

As a side effect, this patch also fixes some anomalous spellings of
"KGDB".

These changes alter the compile types of some integer constants
that are harmless but trigger truncation warnings in gcc when
assigning to 32-bit variables.  This patch adds an explicit cast
for the affected cases.

Signed-off-by: Dave Martin <Dave.Martin@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
2015-07-27 11:08:42 +01:00

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/*
* 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 = (u32)ESR_ELx_VAL_BRK64(KGDB_DYN_DBG_BRK_IMM),
.fn = kgdb_brk_fn
};
static struct break_hook kgdb_compiled_brkpt_hook = {
.esr_mask = 0xffffffff,
.esr_val = (u32)ESR_ELx_VAL_BRK64(KGDB_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_BYTE(0),
KGDB_DYN_BRK_INS_BYTE(1),
KGDB_DYN_BRK_INS_BYTE(2),
KGDB_DYN_BRK_INS_BYTE(3),
}
};
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