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authorMasahiro Yamada <yamada.masahiro@socionext.com>2018-06-26 20:13:48 -0700
committerDavid S. Miller <davem@davemloft.net>2018-06-28 21:39:16 +0900
commit8e75887d321d102200abf3a9fa621e2c10ff4cc5 (patch)
tree6c43fe825ee8cee037dbbfae0a80d9d5f49d0b78 /net/bpfilter
parentstrparser: Remove early eaten to fix full tcp receive buffer stall (diff)
downloadlinux-dev-8e75887d321d102200abf3a9fa621e2c10ff4cc5.tar.xz
linux-dev-8e75887d321d102200abf3a9fa621e2c10ff4cc5.zip
bpfilter: include bpfilter_umh in assembly instead of using objcopy
What we want here is to embed a user-space program into the kernel. Instead of the complex ELF magic, let's simply wrap it in the assembly with the '.incbin' directive. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/bpfilter')
-rw-r--r--net/bpfilter/Makefile17
-rw-r--r--net/bpfilter/bpfilter_kern.c11
-rw-r--r--net/bpfilter/bpfilter_umh_blob.S7
3 files changed, 14 insertions, 21 deletions
diff --git a/net/bpfilter/Makefile b/net/bpfilter/Makefile
index 051dc18b8ccb..39c6980b5d99 100644
--- a/net/bpfilter/Makefile
+++ b/net/bpfilter/Makefile
@@ -15,20 +15,7 @@ ifeq ($(CONFIG_BPFILTER_UMH), y)
HOSTLDFLAGS += -static
endif
-# a bit of elf magic to convert bpfilter_umh binary into a binary blob
-# inside bpfilter_umh.o elf file referenced by
-# _binary_net_bpfilter_bpfilter_umh_start symbol
-# which bpfilter_kern.c passes further into umh blob loader at run-time
-quiet_cmd_copy_umh = GEN $@
- cmd_copy_umh = echo ':' > $(obj)/.bpfilter_umh.o.cmd; \
- $(OBJCOPY) -I binary \
- `LC_ALL=C $(OBJDUMP) -f net/bpfilter/bpfilter_umh \
- |awk -F' |,' '/file format/{print "-O",$$NF} \
- /^architecture:/{print "-B",$$2}'` \
- --rename-section .data=.init.rodata $< $@
-
-$(obj)/bpfilter_umh.o: $(obj)/bpfilter_umh
- $(call cmd,copy_umh)
+$(obj)/bpfilter_umh_blob.o: $(obj)/bpfilter_umh
obj-$(CONFIG_BPFILTER_UMH) += bpfilter.o
-bpfilter-objs += bpfilter_kern.o bpfilter_umh.o
+bpfilter-objs += bpfilter_kern.o bpfilter_umh_blob.o
diff --git a/net/bpfilter/bpfilter_kern.c b/net/bpfilter/bpfilter_kern.c
index 09522573f611..f0fc182d3db7 100644
--- a/net/bpfilter/bpfilter_kern.c
+++ b/net/bpfilter/bpfilter_kern.c
@@ -10,11 +10,8 @@
#include <linux/file.h>
#include "msgfmt.h"
-#define UMH_start _binary_net_bpfilter_bpfilter_umh_start
-#define UMH_end _binary_net_bpfilter_bpfilter_umh_end
-
-extern char UMH_start;
-extern char UMH_end;
+extern char bpfilter_umh_start;
+extern char bpfilter_umh_end;
static struct umh_info info;
/* since ip_getsockopt() can run in parallel, serialize access to umh */
@@ -93,7 +90,9 @@ static int __init load_umh(void)
int err;
/* fork usermode process */
- err = fork_usermode_blob(&UMH_start, &UMH_end - &UMH_start, &info);
+ err = fork_usermode_blob(&bpfilter_umh_start,
+ &bpfilter_umh_end - &bpfilter_umh_start,
+ &info);
if (err)
return err;
pr_info("Loaded bpfilter_umh pid %d\n", info.pid);
diff --git a/net/bpfilter/bpfilter_umh_blob.S b/net/bpfilter/bpfilter_umh_blob.S
new file mode 100644
index 000000000000..40311d10d2f2
--- /dev/null
+++ b/net/bpfilter/bpfilter_umh_blob.S
@@ -0,0 +1,7 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+ .section .init.rodata, "a"
+ .global bpfilter_umh_start
+bpfilter_umh_start:
+ .incbin "net/bpfilter/bpfilter_umh"
+ .global bpfilter_umh_end
+bpfilter_umh_end: