This piece allows to dump a percpu struct or union at a given address
on a given CPU.
Signed-off-by: Petr Tesarik <ptesarik@xxxxxxx>
---
defs.h | 2
global_data.c | 1
help.c | 65 ++++++++++++++++++++++++
symbols.c | 156 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
4 files changed, 224 insertions(+)
Implement basic percpu functionality
This piece allows to dump a percpu struct or union at a given address
on a given CPU.
Signed-off-by: Petr Tesarik <ptesarik@xxxxxxx>
---
defs.h | 2
global_data.c | 1
help.c | 65 ++++++++++++++++++++++++
symbols.c | 156 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
4 files changed, 224 insertions(+)
--- a/defs.h
+++ b/defs.h
@@ -4124,6 +4124,7 @@ void cmd_sym(void); /* symbols.
void cmd_struct(void); /* symbols.c */
void cmd_union(void); /* symbols.c */
void cmd_pointer(void); /* symbols.c */
+void cmd_percpu(void); /* symbols.c */
void cmd_whatis(void); /* symbols.c */
void cmd_p(void); /* symbols.c */
void cmd_mount(void); /* filesys.c */
@@ -4608,6 +4609,7 @@ extern char *help_mod[];
extern char *help_mount[];
extern char *help_net[];
extern char *help_p[];
+extern char *help_percpu[];
extern char *help_ps[];
extern char *help_pte[];
extern char *help_ptob[];
--- a/global_data.c
+++ b/global_data.c
@@ -95,6 +95,7 @@ struct command_table_entry linux_command
{"mount", cmd_mount, help_mount, 0},
{"net", cmd_net, help_net, REFRESH_TASK_TABLE},
{"p", cmd_p, help_p, 0},
+ {"percpu", cmd_percpu, help_percpu, 0},
{"ps", cmd_ps, help_ps, REFRESH_TASK_TABLE},
{"pte", cmd_pte, help_pte, 0},
{"ptob", cmd_ptob, help_ptob, 0},
--- a/help.c
+++ b/help.c
@@ -1147,6 +1147,71 @@ char *help_p[] = {
NULL
};
+char *help_percpu[] = {
+"percpu",
+"percpu variables",
+"[-a] [-c cpu] [cpu]... [struct|union|*] struct_name [address|symbol]",
+" This command displays a formatted display of the contents of a per-cpu",
+" variable for a given set of CPUs.",
+" ",
+" The set of CPUs can be specified in the following ways:\n",
+" -a show all CPUs.",
+" -c cpu specify cpu set, e.g. \"1,3,5\", \"1-3\", or \"1,3,5-7,10\".",
+" cpu show for a specific CPU (numeric only, can be repeated).",
+" ",
+" If no CPU specifiers are present, percpu will use the CPU of the",
+" currently selected task.",
+"\nEXAMPLES",
+" Show the value of a per-cpu variable on processor 2:\n",
+" %s> percpu 2 list_head blk_cpu_iopoll",
+" [2]: ffff88011e290100",
+" struct list_head {",
+" next = 0xffff88011e290100, ",
+" prev = 0xffff88011e290100",
+" }",
+
+" ",
+" Show a per-cpu variable on all processors:\n",
+" %s> percpu -a disk_stats 0x1a468",
+" [0]: ffff88011e21a468",
+" struct disk_stats {",
+" sectors = {11197190, 7550896}, ",
+" ios = {360193, 159113}, ",
+" merges = {11723, 22075}, ",
+" ticks = {6180943, 11137498}, ",
+" io_ticks = 1781827, ",
+" time_in_queue = 16785949",
+" }",
+" [1]: ffff88011e25a468",
+" struct disk_stats {",
+" sectors = {1250132, 173032}, ",
+" ios = {20393, 7573}, ",
+" merges = {26161, 9947}, ",
+" ticks = {415390, 758619}, ",
+" io_ticks = 130165, ",
+" time_in_queue = 1426936",
+" }",
+" [2]: ffff88011e29a468",
+" struct disk_stats {",
+" sectors = {88514, 10136}, ",
+" ios = {1381, 382}, ",
+" merges = {5515, 24870}, ",
+" ticks = {29334, 69079}, ",
+" io_ticks = 18280, ",
+" time_in_queue = 264582",
+" }",
+" [3]: ffff88011e2da468",
+" struct disk_stats {",
+" sectors = {66608, 14128}, ",
+" ios = {2731, 602}, ",
+" merges = {4697, 5173}, ",
+" ticks = {27411, 67344}, ",
+" io_ticks = 13246, ",
+" time_in_queue = 211221",
+" }",
+NULL
+};
+
char *help_ps[] = {
"ps",
"display process status information",
--- a/symbols.c
+++ b/symbols.c
@@ -5987,6 +5987,162 @@ freebuf:
}
}
+/*
+ * This command displays a data type after adjusting the address with
+ * a per-cpu offset.
+ */
+void
+cmd_percpu(void)
+{
+ int c, i;
+ int cpulen;
+ ulong *cpus;
+ int cflag;
+ ulong flags;
+ char *structname, *typename;
+ struct datatype_member datatype_member, *dm = &datatype_member;
+ struct syment *sp;
+ ulong addr;
+ char buf[BUFSIZE];
+
+ cflag = 0;
+
+ if ((cpulen = STRUCT_SIZE("cpumask_t")) < 0)
+ cpulen = DIV_ROUND_UP(kt->cpus, BITS_PER_LONG) * sizeof(ulong);
+ cpus = (ulong *)GETBUF(cpulen);
+
+ while ((c = getopt(argcnt, args, "ac:")) != EOF) {
+ switch (c)
+ {
+ case 'a':
+ for (i = 0; i < kt->cpus; i++)
+ SET_BIT(cpus, i);
+ cflag = 1;
+ break;
+
+ case 'c':
+ make_cpumask(optarg, cpus, FAULT_ON_ERROR, NULL);
+ cflag = 1;
+ break;
+
+ default:
+ argerrs++;
+ break;
+ }
+ }
+
+ while (args[optind] && isdigit(args[optind][0])) {
+ int iserr = FALSE;
+ int cpu = dtoi(args[optind], RETURN_ON_ERROR, &iserr);
+ if (iserr) {
+ FREEBUF(cpus);
+ RESTART();
+ }
+ if (cpu >= kt->cpus) {
+ FREEBUF(cpus);
+ error(FATAL, "CPU %d is out of range\n", cpu);
+ }
+ SET_BIT(cpus, cpu);
+ cflag = 1;
+ ++optind;
+ }
+
+ if (!cflag)
+ SET_BIT(cpus, CURRENT_CONTEXT()->processor);
+
+ flags = 0UL;
+ structname = NULL;
+
+ if (STREQ(args[optind], "struct")) {
+ flags |= STRUCT_REQUEST;
+ structname = args[++optind];
+ } else if (STREQ(args[optind], "union")) {
+ flags |= UNION_REQUEST;
+ structname = args[++optind];
+ } else if (args[optind][0] == '*') {
+ structname = args[optind][1]
+ ? args[optind] + 1
+ : args[++optind];
+ } else {
+ structname = args[optind];
+ }
+ ++optind;
+
+ if (argerrs || !structname || !args[optind] || args[optind+1]) {
+ FREEBUF(cpus);
+ cmd_usage(pc->curcmd, SYNOPSIS);
+ }
+
+ if (arg_to_datatype(structname, dm,
+ DATATYPE_QUERY|ANON_MEMBER_QUERY|RETURN_ON_ERROR) < 1) {
+ FREEBUF(cpus);
+ error(FATAL, "invalid data structure reference: %s\n", structname);
+ }
+
+ if (dm->flags & TYPEDEF) {
+ flags |= dm->type;
+ typename = strdup(dm->name);
+ } else {
+ if (! (flags & (STRUCT_REQUEST|UNION_REQUEST)) )
+ flags |= dm->type;
+ typename = malloc(strlen(dm->name) + 8);
+ sprintf(typename, "%s %s",
+ dm->flags & UNION_REQUEST ? "union" : "struct",
+ dm->name);
+ }
+
+ if ((flags & (STRUCT_REQUEST|UNION_REQUEST)) !=
+ dm->type & (STRUCT_REQUEST|UNION_REQUEST)) {
+ fprintf(fp, "data type mismatch: %s is not a %s\n",
+ structname,
+ flags & UNION_REQUEST ? "union" : "struct");
+ goto freebuf;
+ }
+
+ if (clean_arg() && IS_A_NUMBER(args[optind])) {
+ addr = htol(args[optind], FAULT_ON_ERROR, NULL);
+ } else if ((sp = per_cpu_symbol_search(args[optind]))) {
+ addr = sp->value;
+ } else {
+ if ((sp = symbol_search(args[optind]))) {
+ fprintf(fp, "not a per-cpu symbol: %s\n",
+ args[optind]);
+ } else {
+ fprintf(fp, "symbol not found: %s\n", args[optind]);
+ fprintf(fp, "possible alternatives:\n");
+ if (!symbol_query(args[optind], " ", NULL))
+ fprintf(fp, " (none found)\n");
+ }
+ goto freebuf;
+ }
+
+ for (i = 0; i < kt->cpus; i++) {
+ ulong cpuaddr;
+
+ if (!NUM_IN_BITMAP(cpus, i))
+ continue;
+
+ cpuaddr = addr + kt->__per_cpu_offset[i];
+ fprintf(fp, " [%d]: %lx\n", i, cpuaddr);
+ if (!IS_KVADDR(cpuaddr)) {
+ error(WARNING,
+ "invalid kernel virtual address: 0x%lx\n",
+ cpuaddr);
+ continue;
+ }
+
+ fprintf(fp, "%s ", typename);
+ snprintf(buf, sizeof buf, "output *(%s*) 0x%lx",
+ typename, cpuaddr);
+ gdb_pass_through(buf, NULL, GNU_RETURN_ON_ERROR);
+ fprintf(fp, "\n");
+ }
+
+freebuf:
+ free(typename);
+ FREEBUF(cpus);
+}
+
/*
* Generic function for dumping data structure declarations, with a small
--
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