From d2ccde1c8e90d38cee87a1b0309ad2827f3fd30d Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Mon, 11 Dec 2023 02:45:28 +0000
Subject: [PATCH] add boot partition size
---
kernel/kernel/debug/debug_core.c | 264 +++++++++++++++++++++++++++++++++++++++++++---------
1 files changed, 216 insertions(+), 48 deletions(-)
diff --git a/kernel/kernel/debug/debug_core.c b/kernel/kernel/debug/debug_core.c
index 8c76141..0f31b22 100644
--- a/kernel/kernel/debug/debug_core.c
+++ b/kernel/kernel/debug/debug_core.c
@@ -55,6 +55,8 @@
#include <linux/mm.h>
#include <linux/vmacache.h>
#include <linux/rcupdate.h>
+#include <linux/irq.h>
+#include <linux/security.h>
#include <asm/cacheflush.h>
#include <asm/byteorder.h>
@@ -66,9 +68,7 @@
struct debuggerinfo_struct kgdb_info[NR_CPUS];
-/**
- * kgdb_connected - Is a host GDB connected to us?
- */
+/* kgdb_connected - Is a host GDB connected to us? */
int kgdb_connected;
EXPORT_SYMBOL_GPL(kgdb_connected);
@@ -81,7 +81,7 @@
struct kgdb_io *dbg_io_ops;
static DEFINE_SPINLOCK(kgdb_registration_lock);
-/* Action for the reboot notifiter, a global allow kdb to change it */
+/* Action for the reboot notifier, a global allow kdb to change it */
static int kgdbreboot;
/* kgdb console driver is loaded */
static int kgdb_con_registered;
@@ -156,31 +156,37 @@
/*
* Weak aliases for breakpoint management,
- * can be overriden by architectures when needed:
+ * can be overridden by architectures when needed:
*/
int __weak kgdb_arch_set_breakpoint(struct kgdb_bkpt *bpt)
{
int err;
- err = probe_kernel_read(bpt->saved_instr, (char *)bpt->bpt_addr,
+ err = copy_from_kernel_nofault(bpt->saved_instr, (char *)bpt->bpt_addr,
BREAK_INSTR_SIZE);
if (err)
return err;
- err = probe_kernel_write((char *)bpt->bpt_addr,
+ err = copy_to_kernel_nofault((char *)bpt->bpt_addr,
arch_kgdb_ops.gdb_bpt_instr, BREAK_INSTR_SIZE);
return err;
}
+NOKPROBE_SYMBOL(kgdb_arch_set_breakpoint);
int __weak kgdb_arch_remove_breakpoint(struct kgdb_bkpt *bpt)
{
- return probe_kernel_write((char *)bpt->bpt_addr,
+ return copy_to_kernel_nofault((char *)bpt->bpt_addr,
(char *)bpt->saved_instr, BREAK_INSTR_SIZE);
}
+NOKPROBE_SYMBOL(kgdb_arch_remove_breakpoint);
int __weak kgdb_validate_break_address(unsigned long addr)
{
struct kgdb_bkpt tmp;
int err;
+
+ if (kgdb_within_blocklist(addr))
+ return -EINVAL;
+
/* Validate setting the breakpoint and then removing it. If the
* remove fails, the kernel needs to emit a bad message because we
* are deep trouble not being able to put things back the way we
@@ -201,6 +207,7 @@
{
return instruction_pointer(regs);
}
+NOKPROBE_SYMBOL(kgdb_arch_pc);
int __weak kgdb_arch_init(void)
{
@@ -211,6 +218,65 @@
{
return 0;
}
+NOKPROBE_SYMBOL(kgdb_skipexception);
+
+#ifdef CONFIG_SMP
+
+/*
+ * Default (weak) implementation for kgdb_roundup_cpus
+ */
+
+static DEFINE_PER_CPU(call_single_data_t, kgdb_roundup_csd);
+
+void __weak kgdb_call_nmi_hook(void *ignored)
+{
+ /*
+ * NOTE: get_irq_regs() is supposed to get the registers from
+ * before the IPI interrupt happened and so is supposed to
+ * show where the processor was. In some situations it's
+ * possible we might be called without an IPI, so it might be
+ * safer to figure out how to make kgdb_breakpoint() work
+ * properly here.
+ */
+ kgdb_nmicallback(raw_smp_processor_id(), get_irq_regs());
+}
+NOKPROBE_SYMBOL(kgdb_call_nmi_hook);
+
+void __weak kgdb_roundup_cpus(void)
+{
+ call_single_data_t *csd;
+ int this_cpu = raw_smp_processor_id();
+ int cpu;
+ int ret;
+
+ for_each_online_cpu(cpu) {
+ /* No need to roundup ourselves */
+ if (cpu == this_cpu)
+ continue;
+
+ csd = &per_cpu(kgdb_roundup_csd, cpu);
+
+ /*
+ * If it didn't round up last time, don't try again
+ * since smp_call_function_single_async() will block.
+ *
+ * If rounding_up is false then we know that the
+ * previous call must have at least started and that
+ * means smp_call_function_single_async() won't block.
+ */
+ if (kgdb_info[cpu].rounding_up)
+ continue;
+ kgdb_info[cpu].rounding_up = true;
+
+ csd->func = kgdb_call_nmi_hook;
+ ret = smp_call_function_single_async(cpu, csd);
+ if (ret)
+ kgdb_info[cpu].rounding_up = false;
+ }
+}
+NOKPROBE_SYMBOL(kgdb_roundup_cpus);
+
+#endif
/*
* Some architectures need cache flushes when we set/clear a
@@ -235,6 +301,7 @@
/* Force flush instruction cache if it was outside the mm */
flush_icache_range(addr, addr + BREAK_INSTR_SIZE);
}
+NOKPROBE_SYMBOL(kgdb_flush_swbreak_addr);
/*
* SW breakpoint management:
@@ -262,6 +329,7 @@
}
return ret;
}
+NOKPROBE_SYMBOL(dbg_activate_sw_breakpoints);
int dbg_set_sw_break(unsigned long addr)
{
@@ -325,6 +393,7 @@
}
return ret;
}
+NOKPROBE_SYMBOL(dbg_deactivate_sw_breakpoints);
int dbg_remove_sw_break(unsigned long addr)
{
@@ -347,6 +416,18 @@
for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
if ((kgdb_break[i].state == BP_REMOVED) &&
(kgdb_break[i].bpt_addr == addr))
+ return 1;
+ }
+ return 0;
+}
+
+int kgdb_has_hit_break(unsigned long addr)
+{
+ int i;
+
+ for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
+ if (kgdb_break[i].state == BP_ACTIVE &&
+ kgdb_break[i].bpt_addr == addr)
return 1;
}
return 0;
@@ -376,6 +457,48 @@
return 0;
}
+void kgdb_free_init_mem(void)
+{
+ int i;
+
+ /* Clear init memory breakpoints. */
+ for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
+ if (init_section_contains((void *)kgdb_break[i].bpt_addr, 0))
+ kgdb_break[i].state = BP_UNDEFINED;
+ }
+}
+
+#ifdef CONFIG_KGDB_KDB
+void kdb_dump_stack_on_cpu(int cpu)
+{
+ if (cpu == raw_smp_processor_id() || !IS_ENABLED(CONFIG_SMP)) {
+ dump_stack();
+ return;
+ }
+
+ if (!(kgdb_info[cpu].exception_state & DCPU_IS_SLAVE)) {
+ kdb_printf("ERROR: Task on cpu %d didn't stop in the debugger\n",
+ cpu);
+ return;
+ }
+
+ /*
+ * In general, architectures don't support dumping the stack of a
+ * "running" process that's not the current one. From the point of
+ * view of the Linux, kernel processes that are looping in the kgdb
+ * slave loop are still "running". There's also no API (that actually
+ * works across all architectures) that can do a stack crawl based
+ * on registers passed as a parameter.
+ *
+ * Solve this conundrum by asking slave CPUs to do the backtrace
+ * themselves.
+ */
+ kgdb_info[cpu].exception_state |= DCPU_WANT_BT;
+ while (kgdb_info[cpu].exception_state & DCPU_WANT_BT)
+ cpu_relax();
+}
+#endif
+
/*
* Return true if there is a valid kgdb I/O module. Also if no
* debugger is attached a message can be printed to the console about
@@ -403,6 +526,7 @@
}
return 1;
}
+NOKPROBE_SYMBOL(kgdb_io_ready);
static int kgdb_reenter_check(struct kgdb_state *ks)
{
@@ -450,6 +574,7 @@
return 1;
}
+NOKPROBE_SYMBOL(kgdb_reenter_check);
static void dbg_touch_watchdogs(void)
{
@@ -457,6 +582,7 @@
clocksource_touch_watchdog();
rcu_cpu_stall_reset();
}
+NOKPROBE_SYMBOL(dbg_touch_watchdogs);
static int kgdb_cpu_enter(struct kgdb_state *ks, struct pt_regs *regs,
int exception_state)
@@ -517,6 +643,9 @@
atomic_xchg(&kgdb_active, cpu);
break;
}
+ } else if (kgdb_info[cpu].exception_state & DCPU_WANT_BT) {
+ dump_stack();
+ kgdb_info[cpu].exception_state &= ~DCPU_WANT_BT;
} else if (kgdb_info[cpu].exception_state & DCPU_IS_SLAVE) {
if (!raw_spin_is_locked(&dbg_slave_lock))
goto return_normal;
@@ -593,7 +722,7 @@
/* Signal the other CPUs to enter kgdb_wait() */
else if ((!kgdb_single_step) && kgdb_do_roundup)
- kgdb_roundup_cpus(flags);
+ kgdb_roundup_cpus();
#endif
/*
@@ -628,6 +757,29 @@
continue;
kgdb_connected = 0;
} else {
+ /*
+ * This is a brutal way to interfere with the debugger
+ * and prevent gdb being used to poke at kernel memory.
+ * This could cause trouble if lockdown is applied when
+ * there is already an active gdb session. For now the
+ * answer is simply "don't do that". Typically lockdown
+ * *will* be applied before the debug core gets started
+ * so only developers using kgdb for fairly advanced
+ * early kernel debug can be biten by this. Hopefully
+ * they are sophisticated enough to take care of
+ * themselves, especially with help from the lockdown
+ * message printed on the console!
+ */
+ if (security_locked_down(LOCKDOWN_DBG_WRITE_KERNEL)) {
+ if (IS_ENABLED(CONFIG_KGDB_KDB)) {
+ /* Switch back to kdb if possible... */
+ dbg_kdb_mode = 1;
+ continue;
+ } else {
+ /* ... otherwise just bail */
+ break;
+ }
+ }
error = gdb_serial_stub(ks);
}
@@ -642,6 +794,8 @@
break;
}
}
+
+ dbg_activate_sw_breakpoints();
/* Call the I/O driver's post_exception routine */
if (dbg_io_ops->post_exception)
@@ -685,6 +839,7 @@
return kgdb_info[cpu].ret_state;
}
+NOKPROBE_SYMBOL(kgdb_cpu_enter);
/*
* kgdb_handle_exception() - main entry point from a kernel exception
@@ -729,13 +884,11 @@
arch_kgdb_ops.enable_nmi(1);
return ret;
}
+NOKPROBE_SYMBOL(kgdb_handle_exception);
/*
- * GDB places a breakpoint at this function to know dynamically
- * loaded objects. It's not defined static so that only one instance with this
- * name exists in the kernel.
+ * GDB places a breakpoint at this function to know dynamically loaded objects.
*/
-
static int module_event(struct notifier_block *self, unsigned long val,
void *data)
{
@@ -752,6 +905,8 @@
struct kgdb_state kgdb_var;
struct kgdb_state *ks = &kgdb_var;
+ kgdb_info[cpu].rounding_up = false;
+
memset(ks, 0, sizeof(struct kgdb_state));
ks->cpu = cpu;
ks->linux_regs = regs;
@@ -764,6 +919,7 @@
#endif
return 1;
}
+NOKPROBE_SYMBOL(kgdb_nmicallback);
int kgdb_nmicallin(int cpu, int trapnr, void *regs, int err_code,
atomic_t *send_ready)
@@ -789,6 +945,7 @@
#endif
return 1;
}
+NOKPROBE_SYMBOL(kgdb_nmicallin);
static void kgdb_console_write(struct console *co, const char *s,
unsigned count)
@@ -845,36 +1002,39 @@
kgdb_breakpoint();
}
-static struct sysrq_key_op sysrq_dbg_op = {
+static const struct sysrq_key_op sysrq_dbg_op = {
.handler = sysrq_handle_dbg,
.help_msg = "debug(g)",
.action_msg = "DEBUG",
};
#endif
-static int kgdb_panic_event(struct notifier_block *self,
- unsigned long val,
- void *data)
+void kgdb_panic(const char *msg)
{
+ if (!kgdb_io_module_registered)
+ return;
+
/*
- * Avoid entering the debugger if we were triggered due to a panic
- * We don't want to get stuck waiting for input from user in such case.
- * panic_timeout indicates the system should automatically
+ * We don't want to get stuck waiting for input from user if
+ * "panic_timeout" indicates the system should automatically
* reboot on panic.
*/
if (panic_timeout)
- return NOTIFY_DONE;
+ return;
if (dbg_kdb_mode)
- kdb_printf("PANIC: %s\n", (char *)data);
+ kdb_printf("PANIC: %s\n", msg);
+
kgdb_breakpoint();
- return NOTIFY_DONE;
}
-static struct notifier_block kgdb_panic_event_nb = {
- .notifier_call = kgdb_panic_event,
- .priority = INT_MAX,
-};
+static void kgdb_initial_breakpoint(void)
+{
+ kgdb_break_asap = 0;
+
+ pr_crit("Waiting for connection from remote gdb...\n");
+ kgdb_breakpoint();
+}
void __weak kgdb_arch_late(void)
{
@@ -886,6 +1046,9 @@
if (kgdb_io_module_registered)
kgdb_arch_late();
kdb_init(KDB_INIT_FULL);
+
+ if (kgdb_io_module_registered && kgdb_break_asap)
+ kgdb_initial_breakpoint();
}
static int
@@ -924,8 +1087,6 @@
kgdb_arch_late();
register_module_notifier(&dbg_module_load_nb);
register_reboot_notifier(&dbg_reboot_notifier);
- atomic_notifier_chain_register(&panic_notifier_list,
- &kgdb_panic_event_nb);
#ifdef CONFIG_MAGIC_SYSRQ
register_sysrq_key('g', &sysrq_dbg_op);
#endif
@@ -939,16 +1100,14 @@
static void kgdb_unregister_callbacks(void)
{
/*
- * When this routine is called KGDB should unregister from the
- * panic handler and clean up, making sure it is not handling any
+ * When this routine is called KGDB should unregister from
+ * handlers and clean up, making sure it is not handling any
* break exceptions at the time.
*/
if (kgdb_io_module_registered) {
kgdb_io_module_registered = 0;
unregister_reboot_notifier(&dbg_reboot_notifier);
unregister_module_notifier(&dbg_module_load_nb);
- atomic_notifier_chain_unregister(&panic_notifier_list,
- &kgdb_panic_event_nb);
kgdb_arch_exit();
#ifdef CONFIG_MAGIC_SYSRQ
unregister_sysrq_key('g', &sysrq_dbg_op);
@@ -972,7 +1131,7 @@
atomic_set(&kgdb_break_tasklet_var, 0);
}
-static DECLARE_TASKLET(kgdb_tasklet_breakpoint, kgdb_tasklet_bpt, 0);
+static DECLARE_TASKLET_OLD(kgdb_tasklet_breakpoint, kgdb_tasklet_bpt);
void kgdb_schedule_breakpoint(void)
{
@@ -985,14 +1144,6 @@
}
EXPORT_SYMBOL_GPL(kgdb_schedule_breakpoint);
-static void kgdb_initial_breakpoint(void)
-{
- kgdb_break_asap = 0;
-
- pr_crit("Waiting for connection from remote gdb...\n");
- kgdb_breakpoint();
-}
-
/**
* kgdb_register_io_module - register KGDB IO module
* @new_dbg_io_ops: the io ops vector
@@ -1001,15 +1152,22 @@
*/
int kgdb_register_io_module(struct kgdb_io *new_dbg_io_ops)
{
+ struct kgdb_io *old_dbg_io_ops;
int err;
spin_lock(&kgdb_registration_lock);
- if (dbg_io_ops) {
- spin_unlock(&kgdb_registration_lock);
+ old_dbg_io_ops = dbg_io_ops;
+ if (old_dbg_io_ops) {
+ if (!old_dbg_io_ops->deinit) {
+ spin_unlock(&kgdb_registration_lock);
- pr_err("Another I/O driver is already registered with KGDB\n");
- return -EBUSY;
+ pr_err("KGDB I/O driver %s can't replace %s.\n",
+ new_dbg_io_ops->name, old_dbg_io_ops->name);
+ return -EBUSY;
+ }
+ pr_info("Replacing I/O driver %s with %s\n",
+ old_dbg_io_ops->name, new_dbg_io_ops->name);
}
if (new_dbg_io_ops->init) {
@@ -1024,12 +1182,18 @@
spin_unlock(&kgdb_registration_lock);
+ if (old_dbg_io_ops) {
+ old_dbg_io_ops->deinit();
+ return 0;
+ }
+
pr_info("Registered I/O driver %s\n", new_dbg_io_ops->name);
/* Arm KGDB now. */
kgdb_register_callbacks();
- if (kgdb_break_asap)
+ if (kgdb_break_asap &&
+ (!dbg_is_early || IS_ENABLED(CONFIG_ARCH_HAS_EARLY_DEBUG)))
kgdb_initial_breakpoint();
return 0;
@@ -1058,6 +1222,9 @@
dbg_io_ops = NULL;
spin_unlock(&kgdb_registration_lock);
+
+ if (old_dbg_io_ops->deinit)
+ old_dbg_io_ops->deinit();
pr_info("Unregistered I/O driver %s, debugger disabled\n",
old_dbg_io_ops->name);
@@ -1099,7 +1266,8 @@
kgdb_break_asap = 1;
kdb_init(KDB_INIT_EARLY);
- if (kgdb_io_module_registered)
+ if (kgdb_io_module_registered &&
+ IS_ENABLED(CONFIG_ARCH_HAS_EARLY_DEBUG))
kgdb_initial_breakpoint();
return 0;
--
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