[UNIKRAFT PATCH v2 1/2] lib/uknetdev: Save nw_stack data in a netdevice

[Sharan Santhanam <sharan.santhanam@xxxxxxxxx>]

We extend the uk_netdev to store network stack specific data into
uk_netdev. The size of the of this data is passed to network stack
by setting the CONFIG_UK_NETDEV_SCRATCH_SIZE

Signed-off-by: Sharan Santhanam <sharan.santhanam@xxxxxxxxx>
---
 lib/uknetdev/Makefile.rules           | 20 ++++++++++++++++++++
 lib/uknetdev/include/uk/netdev_core.h |  7 +++++++
 support/build/Makefile.rules          |  2 +-
 3 files changed, 28 insertions(+), 1 deletion(-)
 create mode 100644 lib/uknetdev/Makefile.rules

diff --git a/lib/uknetdev/Makefile.rules b/lib/uknetdev/Makefile.rules
new file mode 100644
index 00000000..7894e163
--- /dev/null
+++ b/lib/uknetdev/Makefile.rules
@@ -0,0 +1,20 @@
+UK_SCRATCH_MEM=0
+UK_SCRATCH_RULE_SET=
+
+.SECONDEXPANSION:
+FORCE:
+
+uk_scratch_mem_set: $$(eval 
CFLAGS-y+=-DCONFIG_UK_NETDEV_SCRATCH_SIZE=$$(UK_SCRATCH_MEM))
+       @:;
+
+.PHONY : uk_scratch_mem_set
+
+
+## reserve memory for the network stack
+## uknetdev_scratch_mem,bytes_of_memory
+define uknetdev_scratch_mem =
+$(if $(strip $(1)),\
+       $(if $(shell test $(1) -gt $(UK_SCRATCH_MEM) && echo "scratch mem 
set"), $(eval UK_SCRATCH_MEM:=$(1))))
+
+$(if $(strip $(UK_SCRATCH_RULE_SET)),,$(eval UK_SCRATCH_RULE_SET:=1) $(eval 
UK_PREPARE-$(CONFIG_LIBUKNETDEV)+=uk_scratch_mem_set))
+endef
diff --git a/lib/uknetdev/include/uk/netdev_core.h 
b/lib/uknetdev/include/uk/netdev_core.h
index dba719fc..827f1872 100644
--- a/lib/uknetdev/include/uk/netdev_core.h
+++ b/lib/uknetdev/include/uk/netdev_core.h
@@ -65,6 +65,10 @@
 extern "C" {
 #endif
 
+#ifndef CONFIG_UK_NETDEV_SCRATCH_SIZE
+#define CONFIG_UK_NETDEV_SCRATCH_SIZE 0
+#endif /* CONFIG_UK_NETDEV_SCRATCH_SIZE */
+
 struct uk_netdev;
 UK_TAILQ_HEAD(uk_netdev_list, struct uk_netdev);
 
@@ -400,6 +404,9 @@ struct uk_netdev {
        struct uk_netdev_tx_queue   *_tx_queue[CONFIG_LIBUKNETDEV_MAXNBQUEUES];
 
        UK_TAILQ_ENTRY(struct uk_netdev) _list;
+#if (CONFIG_UK_NETDEV_SCRATCH_SIZE > 0)
+       char scratch_pad[CONFIG_UK_NETDEV_SCRATCH_SIZE];
+#endif /* CONFIG_UK_NETDEV_SCRATCH_SIZE */
 };
 
 #ifdef __cplusplus
diff --git a/support/build/Makefile.rules b/support/build/Makefile.rules
index 8c096fa5..5f7db8a3 100644
--- a/support/build/Makefile.rules
+++ b/support/build/Makefile.rules
@@ -450,7 +450,7 @@ $(4): $(2) | prepare
                       $($(call vprefix_lib,$(1),CINCLUDES)) $($(call 
vprefix_lib,$(1),CINCLUDES-y)) \
                       $($(call vprefix_src,$(1),$(2),$(3),INCLUDES)) $($(call 
vprefix_src,$(1),$(2),$(3),INCLUDES-y)) \
                       $($(call vprefix_glb,$(3),ARCHFLAGS)) $($(call 
vprefix_glb,$(3),ARCHFLAGS-y)) \
-                      $(CFLAGS) $(CFLAGS-y) \
+                      $(CFLAGS) $$(CFLAGS-y) \
                       $($(call vprefix_lib,$(1),CFLAGS)) $($(call 
vprefix_lib,$(1),CFLAGS-y)) \
                       $($(call vprefix_src,$(1),$(2),$(3),FLAGS)) $($(call 
vprefix_src,$(1),$(2),$(3),FLAGS-y)) \
                       $(5) \
-- 
2.20.1