kgdbts: (1 of 2) fix single step awareness to work correctly with SMP

[linux-flexiantxendom0.git] / drivers / misc / kgdbts.c

diff --git a/drivers/misc/kgdbts.c b/drivers/misc/kgdbts.c
index 997e94d..3cad9fc 100644 (file)
--- a/drivers/misc/kgdbts.c
+++ b/drivers/misc/kgdbts.c
@@ -134,6 +134,9 @@ static int force_hwbrks;
 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
@@ -211,7 +214,7 @@ static unsigned long lookup_addr(char *arg)
        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 +286,16 @@ static void hw_break_val_write(void)
        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);
@@ -324,6 +337,18 @@ static int check_single_step(char *put_str, char *arg)
        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 && !arch_needs_sstep_emulation) {
+               /*
+                * 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);
+               cont_instead_of_sstep = 1;
+               ts.idx -= 4;
+               return 0;
+       }
        if (instruction_pointer(&kgdbts_regs) == addr) {
                eprintk("kgdbts: SingleStep failed at %lx\n",
                           instruction_pointer(&kgdbts_regs));
@@ -368,7 +393,12 @@ static int got_break(char *put_str, char *arg)
 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 +428,11 @@ static void emul_sstep_get(char *arg)
 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:
@@ -502,10 +534,10 @@ static struct test_struct bad_read_test[] = {
 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 */
@@ -523,10 +555,10 @@ static struct test_struct singlestep_break_test[] = {
 static struct test_struct do_fork_test[] = {
        { "?", "S0*" }, /* Clear break points */
        { "do_fork", "OK", sw_break, }, /* set sw breakpoint */
-       { "c", "T0*", }, /* Continue */
+       { "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 }, /* Write registers */
-       { "do_fork", "OK", sw_rem_break }, /*remove breakpoint */
        { "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 */
@@ -541,10 +573,10 @@ static struct test_struct do_fork_test[] = {
 static struct test_struct sys_open_test[] = {
        { "?", "S0*" }, /* Clear break points */
        { "sys_open", "OK", sw_break, }, /* set sw breakpoint */
-       { "c", "T0*", }, /* Continue */
+       { "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 }, /* Write registers */
-       { "sys_open", "OK", sw_rem_break }, /*remove breakpoint */
        { "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 */