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Diffstat (limited to 'arch/x86/kernel/kgdb.c')
-rw-r--r--arch/x86/kernel/kgdb.c647
1 files changed, 434 insertions, 213 deletions
diff --git a/arch/x86/kernel/kgdb.c b/arch/x86/kernel/kgdb.c
index dd74fe7273b..7ec1d5f8d28 100644
--- a/arch/x86/kernel/kgdb.c
+++ b/arch/x86/kernel/kgdb.c
@@ -39,76 +39,107 @@
#include <linux/sched.h>
#include <linux/delay.h>
#include <linux/kgdb.h>
-#include <linux/init.h>
#include <linux/smp.h>
#include <linux/nmi.h>
+#include <linux/hw_breakpoint.h>
+#include <linux/uaccess.h>
+#include <linux/memory.h>
#include <asm/debugreg.h>
#include <asm/apicdef.h>
-#include <asm/system.h>
-
#include <asm/apic.h>
+#include <asm/nmi.h>
-/*
- * Put the error code here just in case the user cares:
- */
-static int gdb_x86errcode;
-
-/*
- * Likewise, the vector number here (since GDB only gets the signal
- * number through the usual means, and that's not very specific):
- */
-static int gdb_x86vector = -1;
+struct dbg_reg_def_t dbg_reg_def[DBG_MAX_REG_NUM] =
+{
+#ifdef CONFIG_X86_32
+ { "ax", 4, offsetof(struct pt_regs, ax) },
+ { "cx", 4, offsetof(struct pt_regs, cx) },
+ { "dx", 4, offsetof(struct pt_regs, dx) },
+ { "bx", 4, offsetof(struct pt_regs, bx) },
+ { "sp", 4, offsetof(struct pt_regs, sp) },
+ { "bp", 4, offsetof(struct pt_regs, bp) },
+ { "si", 4, offsetof(struct pt_regs, si) },
+ { "di", 4, offsetof(struct pt_regs, di) },
+ { "ip", 4, offsetof(struct pt_regs, ip) },
+ { "flags", 4, offsetof(struct pt_regs, flags) },
+ { "cs", 4, offsetof(struct pt_regs, cs) },
+ { "ss", 4, offsetof(struct pt_regs, ss) },
+ { "ds", 4, offsetof(struct pt_regs, ds) },
+ { "es", 4, offsetof(struct pt_regs, es) },
+#else
+ { "ax", 8, offsetof(struct pt_regs, ax) },
+ { "bx", 8, offsetof(struct pt_regs, bx) },
+ { "cx", 8, offsetof(struct pt_regs, cx) },
+ { "dx", 8, offsetof(struct pt_regs, dx) },
+ { "si", 8, offsetof(struct pt_regs, dx) },
+ { "di", 8, offsetof(struct pt_regs, di) },
+ { "bp", 8, offsetof(struct pt_regs, bp) },
+ { "sp", 8, offsetof(struct pt_regs, sp) },
+ { "r8", 8, offsetof(struct pt_regs, r8) },
+ { "r9", 8, offsetof(struct pt_regs, r9) },
+ { "r10", 8, offsetof(struct pt_regs, r10) },
+ { "r11", 8, offsetof(struct pt_regs, r11) },
+ { "r12", 8, offsetof(struct pt_regs, r12) },
+ { "r13", 8, offsetof(struct pt_regs, r13) },
+ { "r14", 8, offsetof(struct pt_regs, r14) },
+ { "r15", 8, offsetof(struct pt_regs, r15) },
+ { "ip", 8, offsetof(struct pt_regs, ip) },
+ { "flags", 4, offsetof(struct pt_regs, flags) },
+ { "cs", 4, offsetof(struct pt_regs, cs) },
+ { "ss", 4, offsetof(struct pt_regs, ss) },
+ { "ds", 4, -1 },
+ { "es", 4, -1 },
+#endif
+ { "fs", 4, -1 },
+ { "gs", 4, -1 },
+};
-/**
- * pt_regs_to_gdb_regs - Convert ptrace regs to GDB regs
- * @gdb_regs: A pointer to hold the registers in the order GDB wants.
- * @regs: The &struct pt_regs of the current process.
- *
- * Convert the pt_regs in @regs into the format for registers that
- * GDB expects, stored in @gdb_regs.
- */
-void pt_regs_to_gdb_regs(unsigned long *gdb_regs, struct pt_regs *regs)
+int dbg_set_reg(int regno, void *mem, struct pt_regs *regs)
{
-#ifndef CONFIG_X86_32
- u32 *gdb_regs32 = (u32 *)gdb_regs;
+ if (
+#ifdef CONFIG_X86_32
+ regno == GDB_SS || regno == GDB_FS || regno == GDB_GS ||
#endif
- gdb_regs[GDB_AX] = regs->ax;
- gdb_regs[GDB_BX] = regs->bx;
- gdb_regs[GDB_CX] = regs->cx;
- gdb_regs[GDB_DX] = regs->dx;
- gdb_regs[GDB_SI] = regs->si;
- gdb_regs[GDB_DI] = regs->di;
- gdb_regs[GDB_BP] = regs->bp;
- gdb_regs[GDB_PC] = regs->ip;
+ regno == GDB_SP || regno == GDB_ORIG_AX)
+ return 0;
+
+ if (dbg_reg_def[regno].offset != -1)
+ memcpy((void *)regs + dbg_reg_def[regno].offset, mem,
+ dbg_reg_def[regno].size);
+ return 0;
+}
+
+char *dbg_get_reg(int regno, void *mem, struct pt_regs *regs)
+{
+ if (regno == GDB_ORIG_AX) {
+ memcpy(mem, &regs->orig_ax, sizeof(regs->orig_ax));
+ return "orig_ax";
+ }
+ 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);
+
#ifdef CONFIG_X86_32
- gdb_regs[GDB_PS] = regs->flags;
- gdb_regs[GDB_DS] = regs->ds;
- gdb_regs[GDB_ES] = regs->es;
- gdb_regs[GDB_CS] = regs->cs;
- gdb_regs[GDB_FS] = 0xFFFF;
- gdb_regs[GDB_GS] = 0xFFFF;
- if (user_mode_vm(regs)) {
- gdb_regs[GDB_SS] = regs->ss;
- gdb_regs[GDB_SP] = regs->sp;
- } else {
- gdb_regs[GDB_SS] = __KERNEL_DS;
- gdb_regs[GDB_SP] = kernel_stack_pointer(regs);
+ switch (regno) {
+ case GDB_SS:
+ if (!user_mode_vm(regs))
+ *(unsigned long *)mem = __KERNEL_DS;
+ break;
+ case GDB_SP:
+ if (!user_mode_vm(regs))
+ *(unsigned long *)mem = kernel_stack_pointer(regs);
+ break;
+ case GDB_GS:
+ case GDB_FS:
+ *(unsigned long *)mem = 0xFFFF;
+ break;
}
-#else
- gdb_regs[GDB_R8] = regs->r8;
- gdb_regs[GDB_R9] = regs->r9;
- gdb_regs[GDB_R10] = regs->r10;
- gdb_regs[GDB_R11] = regs->r11;
- gdb_regs[GDB_R12] = regs->r12;
- gdb_regs[GDB_R13] = regs->r13;
- gdb_regs[GDB_R14] = regs->r14;
- gdb_regs[GDB_R15] = regs->r15;
- gdb_regs32[GDB_PS] = regs->flags;
- gdb_regs32[GDB_CS] = regs->cs;
- gdb_regs32[GDB_SS] = regs->ss;
- gdb_regs[GDB_SP] = kernel_stack_pointer(regs);
#endif
+ return dbg_reg_def[regno].name;
}
/**
@@ -161,83 +192,100 @@ void sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *p)
gdb_regs[GDB_SP] = p->thread.sp;
}
-/**
- * gdb_regs_to_pt_regs - Convert GDB regs to ptrace regs.
- * @gdb_regs: A pointer to hold the registers we've received from GDB.
- * @regs: A pointer to a &struct pt_regs to hold these values in.
- *
- * Convert the GDB regs in @gdb_regs into the pt_regs, and store them
- * in @regs.
- */
-void gdb_regs_to_pt_regs(unsigned long *gdb_regs, struct pt_regs *regs)
-{
-#ifndef CONFIG_X86_32
- u32 *gdb_regs32 = (u32 *)gdb_regs;
-#endif
- regs->ax = gdb_regs[GDB_AX];
- regs->bx = gdb_regs[GDB_BX];
- regs->cx = gdb_regs[GDB_CX];
- regs->dx = gdb_regs[GDB_DX];
- regs->si = gdb_regs[GDB_SI];
- regs->di = gdb_regs[GDB_DI];
- regs->bp = gdb_regs[GDB_BP];
- regs->ip = gdb_regs[GDB_PC];
-#ifdef CONFIG_X86_32
- regs->flags = gdb_regs[GDB_PS];
- regs->ds = gdb_regs[GDB_DS];
- regs->es = gdb_regs[GDB_ES];
- regs->cs = gdb_regs[GDB_CS];
-#else
- regs->r8 = gdb_regs[GDB_R8];
- regs->r9 = gdb_regs[GDB_R9];
- regs->r10 = gdb_regs[GDB_R10];
- regs->r11 = gdb_regs[GDB_R11];
- regs->r12 = gdb_regs[GDB_R12];
- regs->r13 = gdb_regs[GDB_R13];
- regs->r14 = gdb_regs[GDB_R14];
- regs->r15 = gdb_regs[GDB_R15];
- regs->flags = gdb_regs32[GDB_PS];
- regs->cs = gdb_regs32[GDB_CS];
- regs->ss = gdb_regs32[GDB_SS];
-#endif
-}
-
static struct hw_breakpoint {
unsigned enabled;
- unsigned type;
- unsigned len;
unsigned long addr;
-} breakinfo[4];
+ int len;
+ int type;
+ struct perf_event * __percpu *pev;
+} breakinfo[HBP_NUM];
+
+static unsigned long early_dr7;
static void kgdb_correct_hw_break(void)
{
- unsigned long dr7;
- int correctit = 0;
- int breakbit;
int breakno;
- get_debugreg(dr7, 7);
- for (breakno = 0; breakno < 4; breakno++) {
- breakbit = 2 << (breakno << 1);
- if (!(dr7 & breakbit) && breakinfo[breakno].enabled) {
- correctit = 1;
- dr7 |= breakbit;
- dr7 &= ~(0xf0000 << (breakno << 2));
- dr7 |= ((breakinfo[breakno].len << 2) |
- breakinfo[breakno].type) <<
- ((breakno << 2) + 16);
+ for (breakno = 0; breakno < HBP_NUM; breakno++) {
+ struct perf_event *bp;
+ struct arch_hw_breakpoint *info;
+ int val;
+ int cpu = raw_smp_processor_id();
+ if (!breakinfo[breakno].enabled)
+ continue;
+ if (dbg_is_early) {
set_debugreg(breakinfo[breakno].addr, breakno);
-
- } else {
- if ((dr7 & breakbit) && !breakinfo[breakno].enabled) {
- correctit = 1;
- dr7 &= ~breakbit;
- dr7 &= ~(0xf0000 << (breakno << 2));
- }
+ early_dr7 |= encode_dr7(breakno,
+ breakinfo[breakno].len,
+ breakinfo[breakno].type);
+ set_debugreg(early_dr7, 7);
+ continue;
}
+ bp = *per_cpu_ptr(breakinfo[breakno].pev, cpu);
+ info = counter_arch_bp(bp);
+ if (bp->attr.disabled != 1)
+ continue;
+ bp->attr.bp_addr = breakinfo[breakno].addr;
+ bp->attr.bp_len = breakinfo[breakno].len;
+ bp->attr.bp_type = breakinfo[breakno].type;
+ info->address = breakinfo[breakno].addr;
+ info->len = breakinfo[breakno].len;
+ info->type = breakinfo[breakno].type;
+ val = arch_install_hw_breakpoint(bp);
+ if (!val)
+ bp->attr.disabled = 0;
+ }
+ if (!dbg_is_early)
+ hw_breakpoint_restore();
+}
+
+static int hw_break_reserve_slot(int breakno)
+{
+ int cpu;
+ int cnt = 0;
+ struct perf_event **pevent;
+
+ if (dbg_is_early)
+ return 0;
+
+ for_each_online_cpu(cpu) {
+ cnt++;
+ pevent = per_cpu_ptr(breakinfo[breakno].pev, cpu);
+ if (dbg_reserve_bp_slot(*pevent))
+ goto fail;
+ }
+
+ return 0;
+
+fail:
+ for_each_online_cpu(cpu) {
+ cnt--;
+ if (!cnt)
+ break;
+ pevent = per_cpu_ptr(breakinfo[breakno].pev, cpu);
+ dbg_release_bp_slot(*pevent);
+ }
+ return -1;
+}
+
+static int hw_break_release_slot(int breakno)
+{
+ struct perf_event **pevent;
+ int cpu;
+
+ if (dbg_is_early)
+ return 0;
+
+ for_each_online_cpu(cpu) {
+ pevent = per_cpu_ptr(breakinfo[breakno].pev, cpu);
+ if (dbg_release_bp_slot(*pevent))
+ /*
+ * The debugger is responsible for handing the retry on
+ * remove failure.
+ */
+ return -1;
}
- if (correctit)
- set_debugreg(dr7, 7);
+ return 0;
}
static int
@@ -245,12 +293,16 @@ kgdb_remove_hw_break(unsigned long addr, int len, enum kgdb_bptype bptype)
{
int i;
- for (i = 0; i < 4; i++)
+ for (i = 0; i < HBP_NUM; i++)
if (breakinfo[i].addr == addr && breakinfo[i].enabled)
break;
- if (i == 4)
+ if (i == HBP_NUM)
return -1;
+ if (hw_break_release_slot(i)) {
+ printk(KERN_ERR "Cannot remove hw breakpoint at %lx\n", addr);
+ return -1;
+ }
breakinfo[i].enabled = 0;
return 0;
@@ -259,46 +311,77 @@ kgdb_remove_hw_break(unsigned long addr, int len, enum kgdb_bptype bptype)
static void kgdb_remove_all_hw_break(void)
{
int i;
+ int cpu = raw_smp_processor_id();
+ struct perf_event *bp;
- for (i = 0; i < 4; i++)
- memset(&breakinfo[i], 0, sizeof(struct hw_breakpoint));
+ for (i = 0; i < HBP_NUM; i++) {
+ if (!breakinfo[i].enabled)
+ continue;
+ bp = *per_cpu_ptr(breakinfo[i].pev, cpu);
+ if (!bp->attr.disabled) {
+ arch_uninstall_hw_breakpoint(bp);
+ bp->attr.disabled = 1;
+ continue;
+ }
+ if (dbg_is_early)
+ early_dr7 &= ~encode_dr7(i, breakinfo[i].len,
+ breakinfo[i].type);
+ else if (hw_break_release_slot(i))
+ printk(KERN_ERR "KGDB: hw bpt remove failed %lx\n",
+ breakinfo[i].addr);
+ breakinfo[i].enabled = 0;
+ }
}
static int
kgdb_set_hw_break(unsigned long addr, int len, enum kgdb_bptype bptype)
{
- unsigned type;
int i;
- for (i = 0; i < 4; i++)
+ for (i = 0; i < HBP_NUM; i++)
if (!breakinfo[i].enabled)
break;
- if (i == 4)
+ if (i == HBP_NUM)
return -1;
switch (bptype) {
case BP_HARDWARE_BREAKPOINT:
- type = 0;
- len = 1;
+ len = 1;
+ breakinfo[i].type = X86_BREAKPOINT_EXECUTE;
break;
case BP_WRITE_WATCHPOINT:
- type = 1;
+ breakinfo[i].type = X86_BREAKPOINT_WRITE;
break;
case BP_ACCESS_WATCHPOINT:
- type = 3;
+ breakinfo[i].type = X86_BREAKPOINT_RW;
break;
default:
return -1;
}
-
- if (len == 1 || len == 2 || len == 4)
- breakinfo[i].len = len - 1;
- else
+ switch (len) {
+ case 1:
+ breakinfo[i].len = X86_BREAKPOINT_LEN_1;
+ break;
+ case 2:
+ breakinfo[i].len = X86_BREAKPOINT_LEN_2;
+ break;
+ case 4:
+ breakinfo[i].len = X86_BREAKPOINT_LEN_4;
+ break;
+#ifdef CONFIG_X86_64
+ case 8:
+ breakinfo[i].len = X86_BREAKPOINT_LEN_8;
+ break;
+#endif
+ default:
return -1;
-
- breakinfo[i].enabled = 1;
+ }
breakinfo[i].addr = addr;
- breakinfo[i].type = type;
+ if (hw_break_reserve_slot(i)) {
+ breakinfo[i].addr = 0;
+ return -1;
+ }
+ breakinfo[i].enabled = 1;
return 0;
}
@@ -311,27 +394,28 @@ kgdb_set_hw_break(unsigned long addr, int len, enum kgdb_bptype bptype)
* disable hardware debugging while it is processing gdb packets or
* handling exception.
*/
-void kgdb_disable_hw_debug(struct pt_regs *regs)
+static void kgdb_disable_hw_debug(struct pt_regs *regs)
{
+ int i;
+ int cpu = raw_smp_processor_id();
+ struct perf_event *bp;
+
/* Disable hardware debugging while we are in kgdb: */
set_debugreg(0UL, 7);
-}
-
-/**
- * kgdb_post_primary_code - Save error vector/code numbers.
- * @regs: Original pt_regs.
- * @e_vector: Original error vector.
- * @err_code: Original error code.
- *
- * This is needed on architectures which support SMP and KGDB.
- * This function is called after all the slave cpus have been put
- * to a know spin state and the primary CPU has control over KGDB.
- */
-void kgdb_post_primary_code(struct pt_regs *regs, int e_vector, int err_code)
-{
- /* primary processor is completely in the debugger */
- gdb_x86vector = e_vector;
- gdb_x86errcode = err_code;
+ for (i = 0; i < HBP_NUM; i++) {
+ if (!breakinfo[i].enabled)
+ continue;
+ if (dbg_is_early) {
+ early_dr7 &= ~encode_dr7(i, breakinfo[i].len,
+ breakinfo[i].type);
+ continue;
+ }
+ bp = *per_cpu_ptr(breakinfo[i].pev, cpu);
+ if (bp->attr.disabled == 1)
+ continue;
+ arch_uninstall_hw_breakpoint(bp);
+ bp->attr.disabled = 1;
+ }
}
#ifdef CONFIG_SMP
@@ -359,12 +443,12 @@ void kgdb_roundup_cpus(unsigned long flags)
/**
* kgdb_arch_handle_exception - Handle architecture specific GDB packets.
- * @vector: The error vector of the exception that happened.
+ * @e_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.
+ * @remcomInBuffer: The buffer of the packet we have read.
+ * @remcomOutBuffer: The buffer of %BUFMAX bytes to write a packet into.
+ * @linux_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.
@@ -378,9 +462,7 @@ int kgdb_arch_handle_exception(int e_vector, int signo, int err_code,
struct pt_regs *linux_regs)
{
unsigned long addr;
- unsigned long dr6;
char *ptr;
- int newPC;
switch (remcomInBuffer[0]) {
case 'c':
@@ -391,8 +473,6 @@ int kgdb_arch_handle_exception(int e_vector, int signo, int err_code,
linux_regs->ip = addr;
case 'D':
case 'k':
- newPC = linux_regs->ip;
-
/* clear the trace bit */
linux_regs->flags &= ~X86_EFLAGS_TF;
atomic_set(&kgdb_cpu_doing_single_step, -1);
@@ -404,22 +484,6 @@ int kgdb_arch_handle_exception(int e_vector, int signo, int err_code,
raw_smp_processor_id());
}
- get_debugreg(dr6, 6);
- if (!(dr6 & 0x4000)) {
- int breakno;
-
- for (breakno = 0; breakno < 4; breakno++) {
- if (dr6 & (1 << breakno) &&
- breakinfo[breakno].type == 0) {
- /* Set restore flag: */
- linux_regs->flags |= X86_EFLAGS_RF;
- break;
- }
- }
- }
- set_debugreg(0UL, 6);
- kgdb_correct_hw_break();
-
return 0;
}
@@ -449,44 +513,39 @@ single_step_cont(struct pt_regs *regs, struct die_args *args)
static int was_in_debug_nmi[NR_CPUS];
-static int __kgdb_notify(struct die_args *args, unsigned long cmd)
+static int kgdb_nmi_handler(unsigned int cmd, struct pt_regs *regs)
{
- struct pt_regs *regs = args->regs;
-
switch (cmd) {
- case DIE_NMI:
+ case NMI_LOCAL:
if (atomic_read(&kgdb_active) != -1) {
/* KGDB CPU roundup */
kgdb_nmicallback(raw_smp_processor_id(), regs);
was_in_debug_nmi[raw_smp_processor_id()] = 1;
touch_nmi_watchdog();
- return NOTIFY_STOP;
+ return NMI_HANDLED;
}
- return NOTIFY_DONE;
-
- case DIE_NMI_IPI:
- /* Just ignore, we will handle the roundup on DIE_NMI. */
- return NOTIFY_DONE;
+ break;
- case DIE_NMIUNKNOWN:
+ case NMI_UNKNOWN:
if (was_in_debug_nmi[raw_smp_processor_id()]) {
was_in_debug_nmi[raw_smp_processor_id()] = 0;
- return NOTIFY_STOP;
+ return NMI_HANDLED;
}
- return NOTIFY_DONE;
-
- case DIE_NMIWATCHDOG:
- if (atomic_read(&kgdb_active) != -1) {
- /* KGDB CPU roundup: */
- kgdb_nmicallback(raw_smp_processor_id(), regs);
- return NOTIFY_STOP;
- }
- /* Enter debugger: */
break;
+ default:
+ /* do nothing */
+ break;
+ }
+ return NMI_DONE;
+}
+static int __kgdb_notify(struct die_args *args, unsigned long cmd)
+{
+ struct pt_regs *regs = args->regs;
+
+ switch (cmd) {
case DIE_DEBUG:
- if (atomic_read(&kgdb_cpu_doing_single_step) ==
- raw_smp_processor_id()) {
+ if (atomic_read(&kgdb_cpu_doing_single_step) != -1) {
if (user_mode(regs))
return single_step_cont(regs, args);
break;
@@ -501,7 +560,7 @@ static int __kgdb_notify(struct die_args *args, unsigned long cmd)
return NOTIFY_DONE;
}
- if (kgdb_handle_exception(args->trapnr, args->signr, args->err, regs))
+ if (kgdb_handle_exception(args->trapnr, args->signr, cmd, regs))
return NOTIFY_DONE;
/* Must touch watchdog before return to normal operation */
@@ -509,6 +568,24 @@ static int __kgdb_notify(struct die_args *args, unsigned long cmd)
return NOTIFY_STOP;
}
+int kgdb_ll_trap(int cmd, const char *str,
+ struct pt_regs *regs, long err, int trap, int sig)
+{
+ struct die_args args = {
+ .regs = regs,
+ .str = str,
+ .err = err,
+ .trapnr = trap,
+ .signr = sig,
+
+ };
+
+ if (!kgdb_io_module_registered)
+ return NOTIFY_DONE;
+
+ return __kgdb_notify(&args, cmd);
+}
+
static int
kgdb_notify(struct notifier_block *self, unsigned long cmd, void *ptr)
{
@@ -524,11 +601,6 @@ kgdb_notify(struct notifier_block *self, unsigned long cmd, void *ptr)
static struct notifier_block kgdb_notifier = {
.notifier_call = kgdb_notify,
-
- /*
- * Lowest-prio notifier priority, we want to be notified last:
- */
- .priority = -INT_MAX,
};
/**
@@ -539,7 +611,81 @@ static struct notifier_block kgdb_notifier = {
*/
int kgdb_arch_init(void)
{
- return register_die_notifier(&kgdb_notifier);
+ int retval;
+
+ retval = register_die_notifier(&kgdb_notifier);
+ if (retval)
+ goto out;
+
+ retval = register_nmi_handler(NMI_LOCAL, kgdb_nmi_handler,
+ 0, "kgdb");
+ if (retval)
+ goto out1;
+
+ retval = register_nmi_handler(NMI_UNKNOWN, kgdb_nmi_handler,
+ 0, "kgdb");
+
+ if (retval)
+ goto out2;
+
+ return retval;
+
+out2:
+ unregister_nmi_handler(NMI_LOCAL, "kgdb");
+out1:
+ unregister_die_notifier(&kgdb_notifier);
+out:
+ return retval;
+}
+
+static void kgdb_hw_overflow_handler(struct perf_event *event,
+ struct perf_sample_data *data, struct pt_regs *regs)
+{
+ struct task_struct *tsk = current;
+ int i;
+
+ for (i = 0; i < 4; i++)
+ if (breakinfo[i].enabled)
+ tsk->thread.debugreg6 |= (DR_TRAP0 << i);
+}
+
+void kgdb_arch_late(void)
+{
+ int i, cpu;
+ struct perf_event_attr attr;
+ struct perf_event **pevent;
+
+ /*
+ * Pre-allocate the hw breakpoint structions in the non-atomic
+ * portion of kgdb because this operation requires mutexs to
+ * complete.
+ */
+ hw_breakpoint_init(&attr);
+ attr.bp_addr = (unsigned long)kgdb_arch_init;
+ attr.bp_len = HW_BREAKPOINT_LEN_1;
+ attr.bp_type = HW_BREAKPOINT_W;
+ attr.disabled = 1;
+ for (i = 0; i < HBP_NUM; i++) {
+ if (breakinfo[i].pev)
+ continue;
+ breakinfo[i].pev = register_wide_hw_breakpoint(&attr, NULL, NULL);
+ if (IS_ERR((void * __force)breakinfo[i].pev)) {
+ printk(KERN_ERR "kgdb: Could not allocate hw"
+ "breakpoints\nDisabling the kernel debugger\n");
+ breakinfo[i].pev = NULL;
+ kgdb_arch_exit();
+ return;
+ }
+ for_each_online_cpu(cpu) {
+ pevent = per_cpu_ptr(breakinfo[i].pev, cpu);
+ pevent[0]->hw.sample_period = 1;
+ pevent[0]->overflow_handler = kgdb_hw_overflow_handler;
+ if (pevent[0]->destroy != NULL) {
+ pevent[0]->destroy = NULL;
+ release_bp_slot(*pevent);
+ }
+ }
+ }
}
/**
@@ -550,6 +696,15 @@ int kgdb_arch_init(void)
*/
void kgdb_arch_exit(void)
{
+ int i;
+ for (i = 0; i < 4; i++) {
+ if (breakinfo[i].pev) {
+ unregister_wide_hw_breakpoint(breakinfo[i].pev);
+ breakinfo[i].pev = NULL;
+ }
+ }
+ unregister_nmi_handler(NMI_UNKNOWN, "kgdb");
+ unregister_nmi_handler(NMI_LOCAL, "kgdb");
unregister_die_notifier(&kgdb_notifier);
}
@@ -582,12 +737,78 @@ unsigned long kgdb_arch_pc(int exception, struct pt_regs *regs)
return instruction_pointer(regs);
}
+void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long ip)
+{
+ regs->ip = ip;
+}
+
+int kgdb_arch_set_breakpoint(struct kgdb_bkpt *bpt)
+{
+ int err;
+#ifdef CONFIG_DEBUG_RODATA
+ char opc[BREAK_INSTR_SIZE];
+#endif /* CONFIG_DEBUG_RODATA */
+
+ bpt->type = BP_BREAKPOINT;
+ err = probe_kernel_read(bpt->saved_instr, (char *)bpt->bpt_addr,
+ BREAK_INSTR_SIZE);
+ if (err)
+ return err;
+ err = probe_kernel_write((char *)bpt->bpt_addr,
+ arch_kgdb_ops.gdb_bpt_instr, BREAK_INSTR_SIZE);
+#ifdef CONFIG_DEBUG_RODATA
+ if (!err)
+ return err;
+ /*
+ * It is safe to call text_poke() because normal kernel execution
+ * is stopped on all cores, so long as the text_mutex is not locked.
+ */
+ if (mutex_is_locked(&text_mutex))
+ return -EBUSY;
+ text_poke((void *)bpt->bpt_addr, arch_kgdb_ops.gdb_bpt_instr,
+ BREAK_INSTR_SIZE);
+ err = probe_kernel_read(opc, (char *)bpt->bpt_addr, BREAK_INSTR_SIZE);
+ if (err)
+ return err;
+ if (memcmp(opc, arch_kgdb_ops.gdb_bpt_instr, BREAK_INSTR_SIZE))
+ return -EINVAL;
+ bpt->type = BP_POKE_BREAKPOINT;
+#endif /* CONFIG_DEBUG_RODATA */
+ return err;
+}
+
+int kgdb_arch_remove_breakpoint(struct kgdb_bkpt *bpt)
+{
+#ifdef CONFIG_DEBUG_RODATA
+ int err;
+ char opc[BREAK_INSTR_SIZE];
+
+ if (bpt->type != BP_POKE_BREAKPOINT)
+ goto knl_write;
+ /*
+ * It is safe to call text_poke() because normal kernel execution
+ * is stopped on all cores, so long as the text_mutex is not locked.
+ */
+ if (mutex_is_locked(&text_mutex))
+ goto knl_write;
+ text_poke((void *)bpt->bpt_addr, bpt->saved_instr, BREAK_INSTR_SIZE);
+ err = probe_kernel_read(opc, (char *)bpt->bpt_addr, BREAK_INSTR_SIZE);
+ if (err || memcmp(opc, bpt->saved_instr, BREAK_INSTR_SIZE))
+ goto knl_write;
+ return err;
+knl_write:
+#endif /* CONFIG_DEBUG_RODATA */
+ return probe_kernel_write((char *)bpt->bpt_addr,
+ (char *)bpt->saved_instr, BREAK_INSTR_SIZE);
+}
+
struct kgdb_arch arch_kgdb_ops = {
/* Breakpoint instruction: */
.gdb_bpt_instr = { 0xcc },
.flags = KGDB_HW_BREAKPOINT,
.set_hw_breakpoint = kgdb_set_hw_break,
.remove_hw_breakpoint = kgdb_remove_hw_break,
+ .disable_hw_break = kgdb_disable_hw_debug,
.remove_all_hw_break = kgdb_remove_all_hw_break,
.correct_hw_break = kgdb_correct_hw_break,
};
generated by cgit v1.2.3-70-g09d2 (git 2.46.0) at 2025-11-09 07:07:26 +0000