Merge tag 'for_linus-3.4-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/jwessel/kgdb
Pull KGDB/KDB regression fixes from Jason Wessel:
- Fix a Smatch warning that appeared in the 3.4 merge window
- Fix kgdb test suite with SMP for all archs without HW single stepping
- Fix kgdb sw breakpoints with CONFIG_DEBUG_RODATA=y limitations on x86
- Fix oops on kgdb test suite with CONFIG_DEBUG_RODATA
- Fix kgdb test suite with SMP for all archs with HW single stepping
* tag 'for_linus-3.4-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/jwessel/kgdb:
x86,kgdb: Fix DEBUG_RODATA limitation using text_poke()
kgdb,debug_core: pass the breakpoint struct instead of address and memory
kgdbts: (2 of 2) fix single step awareness to work correctly with SMP
kgdbts: (1 of 2) fix single step awareness to work correctly with SMP
kgdbts: Fix kernel oops with CONFIG_DEBUG_RODATA
kdb: Fix smatch warning on dbg_io_ops->is_console
diff --git a/arch/x86/kernel/kgdb.c b/arch/x86/kernel/kgdb.c
index db6720e..8bfb614 100644
--- a/arch/x86/kernel/kgdb.c
+++ b/arch/x86/kernel/kgdb.c
@@ -43,6 +43,8 @@
#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>
@@ -741,6 +743,64 @@
regs->ip = ip;
}
+int kgdb_arch_set_breakpoint(struct kgdb_bkpt *bpt)
+{
+ int err;
+ char opc[BREAK_INSTR_SIZE];
+
+ 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 },
diff --git a/drivers/misc/kgdbts.c b/drivers/misc/kgdbts.c
index 3f7ad83..3aa9a96 100644
--- a/drivers/misc/kgdbts.c
+++ b/drivers/misc/kgdbts.c
@@ -134,12 +134,17 @@
static int hwbreaks_ok;
static int hw_break_val;
static int hw_break_val2;
+static int cont_instead_of_sstep;
+static unsigned long cont_thread_id;
+static unsigned long sstep_thread_id;
#if defined(CONFIG_ARM) || defined(CONFIG_MIPS) || defined(CONFIG_SPARC)
static int arch_needs_sstep_emulation = 1;
#else
static int arch_needs_sstep_emulation;
#endif
+static unsigned long cont_addr;
static unsigned long sstep_addr;
+static int restart_from_top_after_write;
static int sstep_state;
/* Storage for the registers, in GDB format. */
@@ -187,7 +192,8 @@
*/
while (!final_ack)
msleep_interruptible(1500);
-
+ /* Pause for any other threads to exit after final ack. */
+ msleep_interruptible(1000);
if (configured)
kgdb_unregister_io_module(&kgdbts_io_ops);
configured = 0;
@@ -211,7 +217,7 @@
if (!strcmp(arg, "kgdbts_break_test"))
addr = (unsigned long)kgdbts_break_test;
else if (!strcmp(arg, "sys_open"))
- addr = (unsigned long)sys_open;
+ addr = (unsigned long)do_sys_open;
else if (!strcmp(arg, "do_fork"))
addr = (unsigned long)do_fork;
else if (!strcmp(arg, "hw_break_val"))
@@ -283,6 +289,16 @@
hw_break_val++;
}
+static int get_thread_id_continue(char *put_str, char *arg)
+{
+ char *ptr = &put_str[11];
+
+ if (put_str[1] != 'T' || put_str[2] != '0')
+ return 1;
+ kgdb_hex2long(&ptr, &cont_thread_id);
+ return 0;
+}
+
static int check_and_rewind_pc(char *put_str, char *arg)
{
unsigned long addr = lookup_addr(arg);
@@ -299,13 +315,21 @@
if (addr + BREAK_INSTR_SIZE == ip)
offset = -BREAK_INSTR_SIZE;
#endif
- if (strcmp(arg, "silent") && ip + offset != addr) {
+
+ if (arch_needs_sstep_emulation && sstep_addr &&
+ ip + offset == sstep_addr &&
+ ((!strcmp(arg, "sys_open") || !strcmp(arg, "do_fork")))) {
+ /* This is special case for emulated single step */
+ v2printk("Emul: rewind hit single step bp\n");
+ restart_from_top_after_write = 1;
+ } else if (strcmp(arg, "silent") && ip + offset != addr) {
eprintk("kgdbts: BP mismatch %lx expected %lx\n",
ip + offset, addr);
return 1;
}
/* Readjust the instruction pointer if needed */
ip += offset;
+ cont_addr = ip;
#ifdef GDB_ADJUSTS_BREAK_OFFSET
instruction_pointer_set(&kgdbts_regs, ip);
#endif
@@ -315,6 +339,8 @@
static int check_single_step(char *put_str, char *arg)
{
unsigned long addr = lookup_addr(arg);
+ static int matched_id;
+
/*
* From an arch indepent point of view the instruction pointer
* should be on a different instruction
@@ -324,6 +350,29 @@
gdb_regs_to_pt_regs(kgdbts_gdb_regs, &kgdbts_regs);
v2printk("Singlestep stopped at IP: %lx\n",
instruction_pointer(&kgdbts_regs));
+
+ if (sstep_thread_id != cont_thread_id) {
+ /*
+ * Ensure we stopped in the same thread id as before, else the
+ * debugger should continue until the original thread that was
+ * single stepped is scheduled again, emulating gdb's behavior.
+ */
+ v2printk("ThrID does not match: %lx\n", cont_thread_id);
+ if (arch_needs_sstep_emulation) {
+ if (matched_id &&
+ instruction_pointer(&kgdbts_regs) != addr)
+ goto continue_test;
+ matched_id++;
+ ts.idx -= 2;
+ sstep_state = 0;
+ return 0;
+ }
+ cont_instead_of_sstep = 1;
+ ts.idx -= 4;
+ return 0;
+ }
+continue_test:
+ matched_id = 0;
if (instruction_pointer(&kgdbts_regs) == addr) {
eprintk("kgdbts: SingleStep failed at %lx\n",
instruction_pointer(&kgdbts_regs));
@@ -365,10 +414,40 @@
return 1;
}
+static void get_cont_catch(char *arg)
+{
+ /* Always send detach because the test is completed at this point */
+ fill_get_buf("D");
+}
+
+static int put_cont_catch(char *put_str, char *arg)
+{
+ /* This is at the end of the test and we catch any and all input */
+ v2printk("kgdbts: cleanup task: %lx\n", sstep_thread_id);
+ ts.idx--;
+ return 0;
+}
+
+static int emul_reset(char *put_str, char *arg)
+{
+ if (strncmp(put_str, "$OK", 3))
+ return 1;
+ if (restart_from_top_after_write) {
+ restart_from_top_after_write = 0;
+ ts.idx = -1;
+ }
+ return 0;
+}
+
static void emul_sstep_get(char *arg)
{
if (!arch_needs_sstep_emulation) {
- fill_get_buf(arg);
+ if (cont_instead_of_sstep) {
+ cont_instead_of_sstep = 0;
+ fill_get_buf("c");
+ } else {
+ fill_get_buf(arg);
+ }
return;
}
switch (sstep_state) {
@@ -398,9 +477,11 @@
static int emul_sstep_put(char *put_str, char *arg)
{
if (!arch_needs_sstep_emulation) {
- if (!strncmp(put_str+1, arg, 2))
- return 0;
- return 1;
+ char *ptr = &put_str[11];
+ if (put_str[1] != 'T' || put_str[2] != '0')
+ return 1;
+ kgdb_hex2long(&ptr, &sstep_thread_id);
+ return 0;
}
switch (sstep_state) {
case 1:
@@ -411,8 +492,7 @@
v2printk("Stopped at IP: %lx\n",
instruction_pointer(&kgdbts_regs));
/* Want to stop at IP + break instruction size by default */
- sstep_addr = instruction_pointer(&kgdbts_regs) +
- BREAK_INSTR_SIZE;
+ sstep_addr = cont_addr + BREAK_INSTR_SIZE;
break;
case 2:
if (strncmp(put_str, "$OK", 3)) {
@@ -424,6 +504,9 @@
if (strncmp(put_str, "$T0", 3)) {
eprintk("kgdbts: failed continue sstep\n");
return 1;
+ } else {
+ char *ptr = &put_str[11];
+ kgdb_hex2long(&ptr, &sstep_thread_id);
}
break;
case 4:
@@ -502,10 +585,10 @@
static struct test_struct singlestep_break_test[] = {
{ "?", "S0*" }, /* Clear break points */
{ "kgdbts_break_test", "OK", sw_break, }, /* set sw breakpoint */
- { "c", "T0*", }, /* Continue */
+ { "c", "T0*", NULL, get_thread_id_continue }, /* Continue */
+ { "kgdbts_break_test", "OK", sw_rem_break }, /*remove breakpoint */
{ "g", "kgdbts_break_test", NULL, check_and_rewind_pc },
{ "write", "OK", write_regs }, /* Write registers */
- { "kgdbts_break_test", "OK", sw_rem_break }, /*remove breakpoint */
{ "s", "T0*", emul_sstep_get, emul_sstep_put }, /* Single step */
{ "g", "kgdbts_break_test", NULL, check_single_step },
{ "kgdbts_break_test", "OK", sw_break, }, /* set sw breakpoint */
@@ -523,16 +606,16 @@
static struct test_struct do_fork_test[] = {
{ "?", "S0*" }, /* Clear break points */
{ "do_fork", "OK", sw_break, }, /* set sw breakpoint */
- { "c", "T0*", }, /* Continue */
- { "g", "do_fork", NULL, check_and_rewind_pc }, /* check location */
- { "write", "OK", write_regs }, /* Write registers */
+ { "c", "T0*", NULL, get_thread_id_continue }, /* Continue */
{ "do_fork", "OK", sw_rem_break }, /*remove breakpoint */
+ { "g", "do_fork", NULL, check_and_rewind_pc }, /* check location */
+ { "write", "OK", write_regs, emul_reset }, /* Write registers */
{ "s", "T0*", emul_sstep_get, emul_sstep_put }, /* Single step */
{ "g", "do_fork", NULL, check_single_step },
{ "do_fork", "OK", sw_break, }, /* set sw breakpoint */
{ "7", "T0*", skip_back_repeat_test }, /* Loop based on repeat_test */
{ "D", "OK", NULL, final_ack_set }, /* detach and unregister I/O */
- { "", "" },
+ { "", "", get_cont_catch, put_cont_catch },
};
/* Test for hitting a breakpoint at sys_open for what ever the number
@@ -541,16 +624,16 @@
static struct test_struct sys_open_test[] = {
{ "?", "S0*" }, /* Clear break points */
{ "sys_open", "OK", sw_break, }, /* set sw breakpoint */
- { "c", "T0*", }, /* Continue */
- { "g", "sys_open", NULL, check_and_rewind_pc }, /* check location */
- { "write", "OK", write_regs }, /* Write registers */
+ { "c", "T0*", NULL, get_thread_id_continue }, /* Continue */
{ "sys_open", "OK", sw_rem_break }, /*remove breakpoint */
+ { "g", "sys_open", NULL, check_and_rewind_pc }, /* check location */
+ { "write", "OK", write_regs, emul_reset }, /* Write registers */
{ "s", "T0*", emul_sstep_get, emul_sstep_put }, /* Single step */
{ "g", "sys_open", NULL, check_single_step },
{ "sys_open", "OK", sw_break, }, /* set sw breakpoint */
{ "7", "T0*", skip_back_repeat_test }, /* Loop based on repeat_test */
{ "D", "OK", NULL, final_ack_set }, /* detach and unregister I/O */
- { "", "" },
+ { "", "", get_cont_catch, put_cont_catch },
};
/*
@@ -693,8 +776,8 @@
/* This callback is a put char which is when kgdb sends data to
* this I/O module.
*/
- if (ts.tst[ts.idx].get[0] == '\0' &&
- ts.tst[ts.idx].put[0] == '\0') {
+ if (ts.tst[ts.idx].get[0] == '\0' && ts.tst[ts.idx].put[0] == '\0' &&
+ !ts.tst[ts.idx].get_handler) {
eprintk("kgdbts: ERROR: beyond end of test on"
" '%s' line %i\n", ts.name, ts.idx);
return 0;
@@ -907,6 +990,17 @@
if (ptr)
sstep_test = simple_strtol(ptr+1, NULL, 10);
+ /* All HW break point tests */
+ if (arch_kgdb_ops.flags & KGDB_HW_BREAKPOINT) {
+ hwbreaks_ok = 1;
+ v1printk("kgdbts:RUN hw breakpoint test\n");
+ run_breakpoint_test(1);
+ v1printk("kgdbts:RUN hw write breakpoint test\n");
+ run_hw_break_test(1);
+ v1printk("kgdbts:RUN access write breakpoint test\n");
+ run_hw_break_test(0);
+ }
+
/* required internal KGDB tests */
v1printk("kgdbts:RUN plant and detach test\n");
run_plant_and_detach_test(0);
@@ -924,35 +1018,11 @@
/* ===Optional tests=== */
- /* All HW break point tests */
- if (arch_kgdb_ops.flags & KGDB_HW_BREAKPOINT) {
- hwbreaks_ok = 1;
- v1printk("kgdbts:RUN hw breakpoint test\n");
- run_breakpoint_test(1);
- v1printk("kgdbts:RUN hw write breakpoint test\n");
- run_hw_break_test(1);
- v1printk("kgdbts:RUN access write breakpoint test\n");
- run_hw_break_test(0);
- }
-
if (nmi_sleep) {
v1printk("kgdbts:RUN NMI sleep %i seconds test\n", nmi_sleep);
run_nmi_sleep_test(nmi_sleep);
}
-#ifdef CONFIG_DEBUG_RODATA
- /* Until there is an api to write to read-only text segments, use
- * HW breakpoints for the remainder of any tests, else print a
- * failure message if hw breakpoints do not work.
- */
- if (!(arch_kgdb_ops.flags & KGDB_HW_BREAKPOINT && hwbreaks_ok)) {
- eprintk("kgdbts: HW breakpoints do not work,"
- "skipping remaining tests\n");
- return;
- }
- force_hwbrks = 1;
-#endif /* CONFIG_DEBUG_RODATA */
-
/* If the do_fork test is run it will be the last test that is
* executed because a kernel thread will be spawned at the very
* end to unregister the debug hooks.
diff --git a/include/linux/kgdb.h b/include/linux/kgdb.h
index fa39183..c4d2fc1 100644
--- a/include/linux/kgdb.h
+++ b/include/linux/kgdb.h
@@ -63,7 +63,8 @@
BP_HARDWARE_BREAKPOINT,
BP_WRITE_WATCHPOINT,
BP_READ_WATCHPOINT,
- BP_ACCESS_WATCHPOINT
+ BP_ACCESS_WATCHPOINT,
+ BP_POKE_BREAKPOINT,
};
enum kgdb_bpstate {
@@ -207,8 +208,8 @@
/* Optional functions. */
extern int kgdb_validate_break_address(unsigned long addr);
-extern int kgdb_arch_set_breakpoint(unsigned long addr, char *saved_instr);
-extern int kgdb_arch_remove_breakpoint(unsigned long addr, char *bundle);
+extern int kgdb_arch_set_breakpoint(struct kgdb_bkpt *bpt);
+extern int kgdb_arch_remove_breakpoint(struct kgdb_bkpt *bpt);
/**
* kgdb_arch_late - Perform any architecture specific initalization.
diff --git a/kernel/debug/debug_core.c b/kernel/debug/debug_core.c
index 1dc53ba..0557f24 100644
--- a/kernel/debug/debug_core.c
+++ b/kernel/debug/debug_core.c
@@ -160,37 +160,39 @@
* Weak aliases for breakpoint management,
* can be overriden by architectures when needed:
*/
-int __weak kgdb_arch_set_breakpoint(unsigned long addr, char *saved_instr)
+int __weak kgdb_arch_set_breakpoint(struct kgdb_bkpt *bpt)
{
int err;
- err = probe_kernel_read(saved_instr, (char *)addr, BREAK_INSTR_SIZE);
+ err = probe_kernel_read(bpt->saved_instr, (char *)bpt->bpt_addr,
+ BREAK_INSTR_SIZE);
if (err)
return err;
-
- return probe_kernel_write((char *)addr, arch_kgdb_ops.gdb_bpt_instr,
- BREAK_INSTR_SIZE);
+ err = probe_kernel_write((char *)bpt->bpt_addr,
+ arch_kgdb_ops.gdb_bpt_instr, BREAK_INSTR_SIZE);
+ return err;
}
-int __weak kgdb_arch_remove_breakpoint(unsigned long addr, char *bundle)
+int __weak kgdb_arch_remove_breakpoint(struct kgdb_bkpt *bpt)
{
- return probe_kernel_write((char *)addr,
- (char *)bundle, BREAK_INSTR_SIZE);
+ return probe_kernel_write((char *)bpt->bpt_addr,
+ (char *)bpt->saved_instr, BREAK_INSTR_SIZE);
}
int __weak kgdb_validate_break_address(unsigned long addr)
{
- char tmp_variable[BREAK_INSTR_SIZE];
+ struct kgdb_bkpt tmp;
int err;
- /* Validate setting the breakpoint and then removing it. In the
+ /* 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
* found them.
*/
- err = kgdb_arch_set_breakpoint(addr, tmp_variable);
+ tmp.bpt_addr = addr;
+ err = kgdb_arch_set_breakpoint(&tmp);
if (err)
return err;
- err = kgdb_arch_remove_breakpoint(addr, tmp_variable);
+ err = kgdb_arch_remove_breakpoint(&tmp);
if (err)
printk(KERN_ERR "KGDB: Critical breakpoint error, kernel "
"memory destroyed at: %lx", addr);
@@ -234,7 +236,6 @@
*/
int dbg_activate_sw_breakpoints(void)
{
- unsigned long addr;
int error;
int ret = 0;
int i;
@@ -243,16 +244,15 @@
if (kgdb_break[i].state != BP_SET)
continue;
- addr = kgdb_break[i].bpt_addr;
- error = kgdb_arch_set_breakpoint(addr,
- kgdb_break[i].saved_instr);
+ error = kgdb_arch_set_breakpoint(&kgdb_break[i]);
if (error) {
ret = error;
- printk(KERN_INFO "KGDB: BP install failed: %lx", addr);
+ printk(KERN_INFO "KGDB: BP install failed: %lx",
+ kgdb_break[i].bpt_addr);
continue;
}
- kgdb_flush_swbreak_addr(addr);
+ kgdb_flush_swbreak_addr(kgdb_break[i].bpt_addr);
kgdb_break[i].state = BP_ACTIVE;
}
return ret;
@@ -301,7 +301,6 @@
int dbg_deactivate_sw_breakpoints(void)
{
- unsigned long addr;
int error;
int ret = 0;
int i;
@@ -309,15 +308,14 @@
for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
if (kgdb_break[i].state != BP_ACTIVE)
continue;
- addr = kgdb_break[i].bpt_addr;
- error = kgdb_arch_remove_breakpoint(addr,
- kgdb_break[i].saved_instr);
+ error = kgdb_arch_remove_breakpoint(&kgdb_break[i]);
if (error) {
- printk(KERN_INFO "KGDB: BP remove failed: %lx\n", addr);
+ printk(KERN_INFO "KGDB: BP remove failed: %lx\n",
+ kgdb_break[i].bpt_addr);
ret = error;
}
- kgdb_flush_swbreak_addr(addr);
+ kgdb_flush_swbreak_addr(kgdb_break[i].bpt_addr);
kgdb_break[i].state = BP_SET;
}
return ret;
@@ -351,7 +349,6 @@
int dbg_remove_all_break(void)
{
- unsigned long addr;
int error;
int i;
@@ -359,12 +356,10 @@
for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
if (kgdb_break[i].state != BP_ACTIVE)
goto setundefined;
- addr = kgdb_break[i].bpt_addr;
- error = kgdb_arch_remove_breakpoint(addr,
- kgdb_break[i].saved_instr);
+ error = kgdb_arch_remove_breakpoint(&kgdb_break[i]);
if (error)
printk(KERN_ERR "KGDB: breakpoint remove failed: %lx\n",
- addr);
+ kgdb_break[i].bpt_addr);
setundefined:
kgdb_break[i].state = BP_UNDEFINED;
}
diff --git a/kernel/debug/kdb/kdb_io.c b/kernel/debug/kdb/kdb_io.c
index 9b5f17d..bb9520f 100644
--- a/kernel/debug/kdb/kdb_io.c
+++ b/kernel/debug/kdb/kdb_io.c
@@ -743,7 +743,7 @@
kdb_input_flush();
c = console_drivers;
- if (!dbg_io_ops->is_console) {
+ if (dbg_io_ops && !dbg_io_ops->is_console) {
len = strlen(moreprompt);
cp = moreprompt;
while (len--) {
