commit f294197b5511537e6b14d5e1db324f4fc4fdd3f8

Author: Dave Anderson <anderson@redhat.com>

Date:   Fri Jul 6 10:57:50 2018 -0400

    Support for the "bpf" command on RHEL 3.10.0-913.el7 and later

    3.10-based RHEL7 kernels, which contain a backport of the upstream

    eBPF code, but still use the older, pre-4.11, IDR facility that does

    not use radix trees for linking the active bpf_prog and bpf_map

    structures.  Without the patch, the command indicates "bpf: command

    not supported or applicable on this architecture or kernel".

    (anderson@redhat.com)

diff --git a/bpf.c b/bpf.c

index 427263d..8871b76 100644

--- a/bpf.c

+++ b/bpf.c

@@ -45,6 +45,10 @@ static void bpf_prog_gpl_compatible(char *, ulong);

 static void dump_xlated_plain(void *, unsigned int, int);

 static void print_boot_time(unsigned long long, char *, unsigned int);

+static int do_old_idr(int, ulong, struct radix_tree_pair *);

+#define OLD_IDR_INIT   (1)

+#define OLD_IDR_COUNT  (2)

+#define OLD_IDR_GATHER (3)

 #define PROG_ID        (0x1)

 #define MAP_ID         (0x2)

@@ -167,7 +171,6 @@ bpf_init(struct bpf_info *bpf)

 		    !VALID_STRUCT(bpf_map) ||

 		    !VALID_STRUCT(bpf_insn) ||

 		    INVALID_MEMBER(bpf_prog_aux) ||

-		    INVALID_MEMBER(idr_idr_rt) ||

 		    INVALID_MEMBER(bpf_prog_type) ||

 		    INVALID_MEMBER(bpf_prog_tag) ||

 		    INVALID_MEMBER(bpf_prog_jited_len) ||

@@ -210,6 +213,9 @@ bpf_init(struct bpf_info *bpf)

 			mkstring(buf2, VADDR_PRLEN, CENTER|LJUST, "BPF_MAP"),

 			mkstring(buf3, bpf->bpf_map_map_type_size, CENTER|LJUST, "BPF_MAP_TYPE"));

+		if (INVALID_MEMBER(idr_idr_rt))

+			do_old_idr(OLD_IDR_INIT, 0, NULL);

+

 		bpf->status = TRUE;

 		break;

@@ -220,24 +226,38 @@ bpf_init(struct bpf_info *bpf)

 		command_not_supported();

 	}

-	bpf->progs = do_radix_tree(symbol_value("prog_idr") + OFFSET(idr_idr_rt),

-		RADIX_TREE_COUNT, NULL);

+	if (VALID_MEMBER(idr_idr_rt))

+		bpf->progs = do_radix_tree(symbol_value("prog_idr") + OFFSET(idr_idr_rt),

+			RADIX_TREE_COUNT, NULL);

+	else 

+		bpf->progs = do_old_idr(OLD_IDR_COUNT, symbol_value("prog_idr"), NULL);

+

 	if (bpf->progs) {

 		len = sizeof(struct radix_tree_pair) * (bpf->progs+1);

 		bpf->proglist = (struct radix_tree_pair *)GETBUF(len);

 		bpf->proglist[0].index = bpf->progs;

-		bpf->progs = do_radix_tree(symbol_value("prog_idr") + OFFSET(idr_idr_rt),

-			RADIX_TREE_GATHER, bpf->proglist);

+		if (VALID_MEMBER(idr_idr_rt))

+			bpf->progs = do_radix_tree(symbol_value("prog_idr") + OFFSET(idr_idr_rt),

+				RADIX_TREE_GATHER, bpf->proglist);

+		else

+			bpf->progs = do_old_idr(OLD_IDR_GATHER, symbol_value("prog_idr"), bpf->proglist);

 	}

-	bpf->maps = do_radix_tree(symbol_value("map_idr") + OFFSET(idr_idr_rt), 

-		RADIX_TREE_COUNT, NULL);

+	if (VALID_MEMBER(idr_idr_rt))

+		bpf->maps = do_radix_tree(symbol_value("map_idr") + OFFSET(idr_idr_rt), 

+			RADIX_TREE_COUNT, NULL);

+	else

+		bpf->maps = do_old_idr(OLD_IDR_COUNT, symbol_value("map_idr"), NULL);

+

 	if (bpf->maps) {

 		len = sizeof(struct radix_tree_pair) * (bpf->maps+1);

 		bpf->maplist = (struct radix_tree_pair *)GETBUF(len);

 		bpf->maplist[0].index = bpf->maps;

-		bpf->maps = do_radix_tree(symbol_value("map_idr") + OFFSET(idr_idr_rt),

-			RADIX_TREE_GATHER, bpf->maplist);

+		if (VALID_MEMBER(idr_idr_rt))

+			bpf->maps = do_radix_tree(symbol_value("map_idr") + OFFSET(idr_idr_rt),

+				RADIX_TREE_GATHER, bpf->maplist);

+		else

+			bpf->maps = do_old_idr(OLD_IDR_GATHER, symbol_value("map_idr"), bpf->maplist);

 	}

 	bpf->bpf_prog_buf = GETBUF(SIZE(bpf_prog));

@@ -538,8 +558,10 @@ do_map_only:

 	}

 bailout:

-	FREEBUF(bpf->proglist);

-	FREEBUF(bpf->maplist);

+	if (bpf->proglist)

+		FREEBUF(bpf->proglist);

+	if (bpf->maplist)

+		FREEBUF(bpf->maplist);

 	FREEBUF(bpf->bpf_prog_buf);

 	FREEBUF(bpf->bpf_prog_aux_buf);

 	FREEBUF(bpf->bpf_map_buf);

@@ -1255,3 +1277,50 @@ print_boot_time(unsigned long long nsecs, char *buf, unsigned int size)

 	sprintf(buf, "(unknown)");

 #endif

 }

+

+/*

+ *  Borrow the old (pre-radix_tree) IDR facility code used by

+ *  the ipcs command.

+ */

+static int

+do_old_idr(int cmd, ulong idr, struct radix_tree_pair *rtp)

+{

+	int i, max, cur, next_id, total = 0;

+	ulong entry;

+

+	switch (cmd)

+	{

+	case OLD_IDR_INIT:

+		ipcs_init();

+		break;

+

+	case OLD_IDR_COUNT:

+		readmem(idr + OFFSET(idr_cur), KVADDR, &cur, 

+			sizeof(int), "idr.cur", FAULT_ON_ERROR);

+		for (total = next_id = 0; next_id < cur; next_id++) {

+			entry = idr_find(idr, next_id);

+			if (entry == 0)

+				continue;

+			total++;

+		}

+		break;

+

+	case OLD_IDR_GATHER:

+		max = rtp[0].index;

+		readmem(idr + OFFSET(idr_cur), KVADDR, &cur, 

+			sizeof(int), "idr.cur", FAULT_ON_ERROR);

+		for (i = total = next_id = 0; next_id < cur; next_id++) {

+			entry = idr_find(idr, next_id);

+			if (entry == 0)

+				continue;

+			total++;

+			rtp[i].index = next_id;

+			rtp[i].value = (void *)entry;

+			if (++i == max)

+				break;

+		}

+		break;

+	}

+

+	return total;

+}

diff --git a/defs.h b/defs.h

index e6e3850..b05aecc 100644

--- a/defs.h

+++ b/defs.h

@@ -2031,6 +2031,7 @@ struct offset_table {                    /* stash of commonly-used offsets */

 	long bpf_prog_aux_load_time;

 	long bpf_prog_aux_user;

 	long user_struct_uid;

+	long idr_cur;

 };

 struct size_table {         /* stash of commonly-used sizes */

@@ -5590,6 +5591,12 @@ enum {

 void dev_init(void);

 void dump_dev_table(void);

+/*

+ *  ipcs.c

+ */

+void ipcs_init(void);

+ulong idr_find(ulong, int);

+

 #ifdef ARM

 void arm_init(int);

 void arm_dump_machdep_table(ulong);

diff --git a/ipcs.c b/ipcs.c

index ef51fdd..80f78e4 100644

--- a/ipcs.c

+++ b/ipcs.c

@@ -79,13 +79,11 @@ struct ipcs_table {

  * function declaration

  */

-static void ipcs_init(void);

 static int dump_shared_memory(int, ulong, int, ulong);

 static int dump_semaphore_arrays(int, ulong, int, ulong);

 static int dump_message_queues(int, ulong, int, ulong);

 static int ipc_search_idr(ulong, int, ulong, int (*)(ulong, int, ulong, int, int), int);

 static int ipc_search_array(ulong, int, ulong, int (*)(ulong, int, ulong, int, int), int);

-static ulong idr_find(ulong, int);

 static int dump_shm_info(ulong, int, ulong, int, int);

 static int dump_sem_info(ulong, int, ulong, int, int);

 static int dump_msg_info(ulong, int, ulong, int, int);

@@ -101,7 +99,7 @@ static void gather_radix_tree_entries(ulong);

  */

 static struct ipcs_table ipcs_table = { 0 };

-static void

+void

 ipcs_init(void)

 {

 	if (ipcs_table.init_flags & IPCS_INIT) {

@@ -119,6 +117,7 @@ ipcs_init(void)

 	MEMBER_OFFSET_INIT(idr_layer_layer, "idr_layer", "layer");

 	MEMBER_OFFSET_INIT(idr_layer_ary, "idr_layer", "ary");

 	MEMBER_OFFSET_INIT(idr_top, "idr", "top");

+	MEMBER_OFFSET_INIT(idr_cur, "idr", "cur");

 	MEMBER_OFFSET_INIT(ipc_id_ary_p, "ipc_id_ary", "p");

 	MEMBER_OFFSET_INIT(ipc_ids_entries, "ipc_ids", "entries");

 	MEMBER_OFFSET_INIT(ipc_ids_max_id, "ipc_ids", "max_id");

@@ -188,7 +187,10 @@ ipcs_init(void)

 		ipcs_table.shm_f_op_huge_addr = -1;

 	}

-	if (BITS32())

+	if (VALID_MEMBER(idr_layer_ary) && 

+	    get_array_length("idr_layer.ary", NULL, 0) > 64)

+		ipcs_table.idr_bits = 8;

+	else if (BITS32())

 		ipcs_table.idr_bits = 5;

 	else if (BITS64())

 		ipcs_table.idr_bits = 6;

@@ -635,7 +637,7 @@ ipc_search_idr(ulong ipc_ids_p, int specified, ulong specified_value, int (*fn)(

 /*

  * search every idr_layer

  */

-static ulong

+ulong

 idr_find(ulong idp, int id)

 {

 	ulong idr_layer_p;

diff --git a/symbols.c b/symbols.c

index bf55319..8ff1430 100644

--- a/symbols.c

+++ b/symbols.c

@@ -10041,6 +10041,8 @@ dump_offset_table(char *spec, ulong makestruct)

 		OFFSET(idr_layers));

 	fprintf(fp, "                       idr_top: %ld\n",

 		OFFSET(idr_top));

+	fprintf(fp, "                       idr_cur: %ld\n",

+		OFFSET(idr_cur));

 	fprintf(fp, "                  ipc_id_ary_p: %ld\n",

 		OFFSET(ipc_id_ary_p));

 	fprintf(fp, "               ipc_ids_entries: %ld\n",