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linux/arch/tile/kernel/kgdb.c
Chen Gang a5c1cb63dd arch: tile: kernel: kgdb.c: Use memcpy() instead of pointer copy one by one 
Not only memcpy() is faster than pointer copy, but also let code more
clearer and simple, which can avoid compiling warning (the original
implementation copy registers by exceeding member array border).

The related warning (with allmodconfig under tile):

    CC      arch/tile/kernel/kgdb.o
  arch/tile/kernel/kgdb.c: In function 'sleeping_thread_to_gdb_regs':
  arch/tile/kernel/kgdb.c:140:31: warning: iteration 53u invokes undefined behavior [-Waggressive-loop-optimizations]
     *(ptr++) = thread_regs->regs[reg];
                                 ^
  arch/tile/kernel/kgdb.c:139:2: note: containing loop
    for (reg = 0; reg <= TREG_LAST_GPR; reg++)
    ^

Signed-off-by: Chen Gang <gang.chen.5i5j@gmail.com>
Signed-off-by: Chris Metcalf <cmetcalf@ezchip.com>
2014-11-12 14:27:10 -05:00

496 lines
15 KiB
C
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/*
* Copyright 2013 Tilera Corporation. All Rights Reserved.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation, version 2.
*
* 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, GOOD TITLE or
* NON INFRINGEMENT. See the GNU General Public License for
* more details.
*
* TILE-Gx KGDB support.
*/
#include <linux/ptrace.h>
#include <linux/kgdb.h>
#include <linux/kdebug.h>
#include <linux/uaccess.h>
#include <linux/module.h>
#include <asm/cacheflush.h>
static tile_bundle_bits singlestep_insn = TILEGX_BPT_BUNDLE | DIE_SSTEPBP;
static unsigned long stepped_addr;
static tile_bundle_bits stepped_instr;
struct dbg_reg_def_t dbg_reg_def[DBG_MAX_REG_NUM] = {
{ "r0", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[0])},
{ "r1", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[1])},
{ "r2", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[2])},
{ "r3", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[3])},
{ "r4", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[4])},
{ "r5", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[5])},
{ "r6", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[6])},
{ "r7", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[7])},
{ "r8", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[8])},
{ "r9", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[9])},
{ "r10", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[10])},
{ "r11", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[11])},
{ "r12", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[12])},
{ "r13", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[13])},
{ "r14", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[14])},
{ "r15", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[15])},
{ "r16", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[16])},
{ "r17", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[17])},
{ "r18", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[18])},
{ "r19", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[19])},
{ "r20", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[20])},
{ "r21", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[21])},
{ "r22", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[22])},
{ "r23", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[23])},
{ "r24", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[24])},
{ "r25", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[25])},
{ "r26", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[26])},
{ "r27", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[27])},
{ "r28", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[28])},
{ "r29", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[29])},
{ "r30", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[30])},
{ "r31", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[31])},
{ "r32", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[32])},
{ "r33", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[33])},
{ "r34", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[34])},
{ "r35", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[35])},
{ "r36", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[36])},
{ "r37", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[37])},
{ "r38", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[38])},
{ "r39", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[39])},
{ "r40", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[40])},
{ "r41", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[41])},
{ "r42", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[42])},
{ "r43", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[43])},
{ "r44", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[44])},
{ "r45", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[45])},
{ "r46", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[46])},
{ "r47", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[47])},
{ "r48", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[48])},
{ "r49", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[49])},
{ "r50", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[50])},
{ "r51", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[51])},
{ "r52", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[52])},
{ "tp", GDB_SIZEOF_REG, offsetof(struct pt_regs, tp)},
{ "sp", GDB_SIZEOF_REG, offsetof(struct pt_regs, sp)},
{ "lr", GDB_SIZEOF_REG, offsetof(struct pt_regs, lr)},
{ "sn", GDB_SIZEOF_REG, -1},
{ "idn0", GDB_SIZEOF_REG, -1},
{ "idn1", GDB_SIZEOF_REG, -1},
{ "udn0", GDB_SIZEOF_REG, -1},
{ "udn1", GDB_SIZEOF_REG, -1},
{ "udn2", GDB_SIZEOF_REG, -1},
{ "udn3", GDB_SIZEOF_REG, -1},
{ "zero", GDB_SIZEOF_REG, -1},
{ "pc", GDB_SIZEOF_REG, offsetof(struct pt_regs, pc)},
{ "faultnum", GDB_SIZEOF_REG, offsetof(struct pt_regs, faultnum)},
};
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;
}
/*
* Similar to pt_regs_to_gdb_regs() except that process is sleeping and so
* we may not be able to get all the info.
*/
void
sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *task)
{
struct pt_regs *thread_regs;
if (task == NULL)
return;
/* Initialize to zero. */
memset(gdb_regs, 0, NUMREGBYTES);
thread_regs = task_pt_regs(task);
memcpy(gdb_regs, thread_regs, TREG_LAST_GPR * sizeof(unsigned long));
gdb_regs[TILEGX_PC_REGNUM] = thread_regs->pc;
gdb_regs[TILEGX_FAULTNUM_REGNUM] = thread_regs->faultnum;
}
void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long pc)
{
regs->pc = pc;
}
static void kgdb_call_nmi_hook(void *ignored)
{
kgdb_nmicallback(raw_smp_processor_id(), NULL);
}
void kgdb_roundup_cpus(unsigned long flags)
{
local_irq_enable();
smp_call_function(kgdb_call_nmi_hook, NULL, 0);
local_irq_disable();
}
/*
* Convert a kernel address to the writable kernel text mapping.
*/
static unsigned long writable_address(unsigned long addr)
{
unsigned long ret = 0;
if (core_kernel_text(addr))
ret = addr - MEM_SV_START + PAGE_OFFSET;
else if (is_module_text_address(addr))
ret = addr;
else
pr_err("Unknown virtual address 0x%lx\n", addr);
return ret;
}
/*
* Calculate the new address for after a step.
*/
static unsigned long get_step_address(struct pt_regs *regs)
{
int src_reg;
int jump_off;
int br_off;
unsigned long addr;
unsigned int opcode;
tile_bundle_bits bundle;
/* Move to the next instruction by default. */
addr = regs->pc + TILEGX_BUNDLE_SIZE_IN_BYTES;
bundle = *(unsigned long *)instruction_pointer(regs);
/* 0: X mode, Otherwise: Y mode. */
if (bundle & TILEGX_BUNDLE_MODE_MASK) {
if (get_Opcode_Y1(bundle) == RRR_1_OPCODE_Y1 &&
get_RRROpcodeExtension_Y1(bundle) ==
UNARY_RRR_1_OPCODE_Y1) {
opcode = get_UnaryOpcodeExtension_Y1(bundle);
switch (opcode) {
case JALR_UNARY_OPCODE_Y1:
case JALRP_UNARY_OPCODE_Y1:
case JR_UNARY_OPCODE_Y1:
case JRP_UNARY_OPCODE_Y1:
src_reg = get_SrcA_Y1(bundle);
dbg_get_reg(src_reg, &addr, regs);
break;
}
}
} else if (get_Opcode_X1(bundle) == RRR_0_OPCODE_X1) {
if (get_RRROpcodeExtension_X1(bundle) ==
UNARY_RRR_0_OPCODE_X1) {
opcode = get_UnaryOpcodeExtension_X1(bundle);
switch (opcode) {
case JALR_UNARY_OPCODE_X1:
case JALRP_UNARY_OPCODE_X1:
case JR_UNARY_OPCODE_X1:
case JRP_UNARY_OPCODE_X1:
src_reg = get_SrcA_X1(bundle);
dbg_get_reg(src_reg, &addr, regs);
break;
}
}
} else if (get_Opcode_X1(bundle) == JUMP_OPCODE_X1) {
opcode = get_JumpOpcodeExtension_X1(bundle);
switch (opcode) {
case JAL_JUMP_OPCODE_X1:
case J_JUMP_OPCODE_X1:
jump_off = sign_extend(get_JumpOff_X1(bundle), 27);
addr = regs->pc +
(jump_off << TILEGX_LOG2_BUNDLE_SIZE_IN_BYTES);
break;
}
} else if (get_Opcode_X1(bundle) == BRANCH_OPCODE_X1) {
br_off = 0;
opcode = get_BrType_X1(bundle);
switch (opcode) {
case BEQZT_BRANCH_OPCODE_X1:
case BEQZ_BRANCH_OPCODE_X1:
if (get_SrcA_X1(bundle) == 0)
br_off = get_BrOff_X1(bundle);
break;
case BGEZT_BRANCH_OPCODE_X1:
case BGEZ_BRANCH_OPCODE_X1:
if (get_SrcA_X1(bundle) >= 0)
br_off = get_BrOff_X1(bundle);
break;
case BGTZT_BRANCH_OPCODE_X1:
case BGTZ_BRANCH_OPCODE_X1:
if (get_SrcA_X1(bundle) > 0)
br_off = get_BrOff_X1(bundle);
break;
case BLBCT_BRANCH_OPCODE_X1:
case BLBC_BRANCH_OPCODE_X1:
if (!(get_SrcA_X1(bundle) & 1))
br_off = get_BrOff_X1(bundle);
break;
case BLBST_BRANCH_OPCODE_X1:
case BLBS_BRANCH_OPCODE_X1:
if (get_SrcA_X1(bundle) & 1)
br_off = get_BrOff_X1(bundle);
break;
case BLEZT_BRANCH_OPCODE_X1:
case BLEZ_BRANCH_OPCODE_X1:
if (get_SrcA_X1(bundle) <= 0)
br_off = get_BrOff_X1(bundle);
break;
case BLTZT_BRANCH_OPCODE_X1:
case BLTZ_BRANCH_OPCODE_X1:
if (get_SrcA_X1(bundle) < 0)
br_off = get_BrOff_X1(bundle);
break;
case BNEZT_BRANCH_OPCODE_X1:
case BNEZ_BRANCH_OPCODE_X1:
if (get_SrcA_X1(bundle) != 0)
br_off = get_BrOff_X1(bundle);
break;
}
if (br_off != 0) {
br_off = sign_extend(br_off, 17);
addr = regs->pc +
(br_off << TILEGX_LOG2_BUNDLE_SIZE_IN_BYTES);
}
}
return addr;
}
/*
* Replace the next instruction after the current instruction with a
* breakpoint instruction.
*/
static void do_single_step(struct pt_regs *regs)
{
unsigned long addr_wr;
/* Determine where the target instruction will send us to. */
stepped_addr = get_step_address(regs);
probe_kernel_read((char *)&stepped_instr, (char *)stepped_addr,
BREAK_INSTR_SIZE);
addr_wr = writable_address(stepped_addr);
probe_kernel_write((char *)addr_wr, (char *)&singlestep_insn,
BREAK_INSTR_SIZE);
smp_wmb();
flush_icache_range(stepped_addr, stepped_addr + BREAK_INSTR_SIZE);
}
static void undo_single_step(struct pt_regs *regs)
{
unsigned long addr_wr;
if (stepped_instr == 0)
return;
addr_wr = writable_address(stepped_addr);
probe_kernel_write((char *)addr_wr, (char *)&stepped_instr,
BREAK_INSTR_SIZE);
stepped_instr = 0;
smp_wmb();
flush_icache_range(stepped_addr, stepped_addr + BREAK_INSTR_SIZE);
}
/*
* Calls linux_debug_hook before the kernel dies. If KGDB is enabled,
* then try to fall into the debugger.
*/
static int
kgdb_notify(struct notifier_block *self, unsigned long cmd, void *ptr)
{
int ret;
unsigned long flags;
struct die_args *args = (struct die_args *)ptr;
struct pt_regs *regs = args->regs;
#ifdef CONFIG_KPROBES
/*
* Return immediately if the kprobes fault notifier has set
* DIE_PAGE_FAULT.
*/
if (cmd == DIE_PAGE_FAULT)
return NOTIFY_DONE;
#endif /* CONFIG_KPROBES */
switch (cmd) {
case DIE_BREAK:
case DIE_COMPILED_BPT:
break;
case DIE_SSTEPBP:
local_irq_save(flags);
kgdb_handle_exception(0, SIGTRAP, 0, regs);
local_irq_restore(flags);
return NOTIFY_STOP;
default:
/* Userspace events, ignore. */
if (user_mode(regs))
return NOTIFY_DONE;
}
local_irq_save(flags);
ret = kgdb_handle_exception(args->trapnr, args->signr, args->err, regs);
local_irq_restore(flags);
if (ret)
return NOTIFY_DONE;
return NOTIFY_STOP;
}
static struct notifier_block kgdb_notifier = {
.notifier_call = kgdb_notify,
};
/*
* kgdb_arch_handle_exception - Handle architecture specific GDB packets.
* @vector: The error vector of the exception that happened.
* @signo: The signal number of the exception that happened.
* @err_code: The error code of the exception that happened.
* @remcom_in_buffer: The buffer of the packet we have read.
* @remcom_out_buffer: The buffer of %BUFMAX bytes to write a packet into.
* @regs: The &struct pt_regs of the current process.
*
* This function MUST handle the 'c' and 's' command packets,
* as well packets to set / remove a hardware breakpoint, if used.
* If there are additional packets which the hardware needs to handle,
* they are handled here. The code should return -1 if it wants to
* process more packets, and a %0 or %1 if it wants to exit from the
* kgdb callback.
*/
int kgdb_arch_handle_exception(int vector, int signo, int err_code,
char *remcom_in_buffer, char *remcom_out_buffer,
struct pt_regs *regs)
{
char *ptr;
unsigned long address;
/* Undo any stepping we may have done. */
undo_single_step(regs);
switch (remcom_in_buffer[0]) {
case 'c':
case 's':
case 'D':
case 'k':
/*
* Try to read optional parameter, pc unchanged if no parm.
* If this was a compiled-in breakpoint, we need to move
* to the next instruction or we will just breakpoint
* over and over again.
*/
ptr = &remcom_in_buffer[1];
if (kgdb_hex2long(&ptr, &address))
regs->pc = address;
else if (*(unsigned long *)regs->pc == compiled_bpt)
regs->pc += BREAK_INSTR_SIZE;
if (remcom_in_buffer[0] == 's') {
do_single_step(regs);
kgdb_single_step = 1;
atomic_set(&kgdb_cpu_doing_single_step,
raw_smp_processor_id());
} else
atomic_set(&kgdb_cpu_doing_single_step, -1);
return 0;
}
return -1; /* this means that we do not want to exit from the handler */
}
struct kgdb_arch arch_kgdb_ops;
/*
* kgdb_arch_init - Perform any architecture specific initalization.
*
* This function will handle the initalization of any architecture
* specific callbacks.
*/
int kgdb_arch_init(void)
{
tile_bundle_bits bundle = TILEGX_BPT_BUNDLE;
memcpy(arch_kgdb_ops.gdb_bpt_instr, &bundle, BREAK_INSTR_SIZE);
return register_die_notifier(&kgdb_notifier);
}
/*
* 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_die_notifier(&kgdb_notifier);
}
int kgdb_arch_set_breakpoint(struct kgdb_bkpt *bpt)
{
int err;
unsigned long addr_wr = writable_address(bpt->bpt_addr);
if (addr_wr == 0)
return -1;
err = probe_kernel_read(bpt->saved_instr, (char *)bpt->bpt_addr,
BREAK_INSTR_SIZE);
if (err)
return err;
err = probe_kernel_write((char *)addr_wr, arch_kgdb_ops.gdb_bpt_instr,
BREAK_INSTR_SIZE);
smp_wmb();
flush_icache_range((unsigned long)bpt->bpt_addr,
(unsigned long)bpt->bpt_addr + BREAK_INSTR_SIZE);
return err;
}
int kgdb_arch_remove_breakpoint(struct kgdb_bkpt *bpt)
{
int err;
unsigned long addr_wr = writable_address(bpt->bpt_addr);
if (addr_wr == 0)
return -1;
err = probe_kernel_write((char *)addr_wr, (char *)bpt->saved_instr,
BREAK_INSTR_SIZE);
smp_wmb();
flush_icache_range((unsigned long)bpt->bpt_addr,
(unsigned long)bpt->bpt_addr + BREAK_INSTR_SIZE);
return err;
}
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