diff mbox series

[v3,02/32] Mini-OS: explicitly mark symbols to be visible for apps

Message ID 20231127102523.28003-3-jgross@suse.com (mailing list archive)
State New, archived
Headers show
Series Mini-OS: hide mini-os internal symbols | expand

Commit Message

Juergen Gross Nov. 27, 2023, 10:24 a.m. UTC 
Add an EXPORT_SYMBOL() macro to explicitly mark a symbol to be visible
for an app or library linked with Mini-OS. This prepares hiding all
other symbols from external components, avoiding any problems with
duplicate symbol names.

Signed-off-by: Juergen Gross <jgross@suse.com>
---
V3:
- new patch
---
 .gitignore       |  1 +
 Makefile         |  3 ++-
 include/export.h | 10 ++++++++++
 include/lib.h    |  1 +
 4 files changed, 14 insertions(+), 1 deletion(-)
 create mode 100644 include/export.h

Comments

Samuel Thibault Nov. 27, 2023, 7:57 p.m. UTC | #1 
Juergen Gross, le lun. 27 nov. 2023 11:24:53 +0100, a ecrit:
> Add an EXPORT_SYMBOL() macro to explicitly mark a symbol to be visible
> for an app or library linked with Mini-OS. This prepares hiding all
> other symbols from external components, avoiding any problems with
> duplicate symbol names.
> 
> Signed-off-by: Juergen Gross <jgross@suse.com>

Reviewed-by: Samuel Thibault <samuel.thibault@ens-lyon.org>

> ---
> V3:
> - new patch
> ---
>  .gitignore       |  1 +
>  Makefile         |  3 ++-
>  include/export.h | 10 ++++++++++
>  include/lib.h    |  1 +
>  4 files changed, 14 insertions(+), 1 deletion(-)
>  create mode 100644 include/export.h
> 
> diff --git a/.gitignore b/.gitignore
> index abef46b2..bacf787e 100644
> --- a/.gitignore
> +++ b/.gitignore
> @@ -16,3 +16,4 @@ mini-os.gz
>  minios-config.mk
>  mini-os-debug
>  mini-os-debug.gz
> +syms
> diff --git a/Makefile b/Makefile
> index 85c6db75..588496cb 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -166,10 +166,11 @@ $(OBJ_DIR)/arch/x86/minios-x86%.lds:  arch/x86/minios-x86.lds.S
>  
>  $(OBJ_DIR)/$(TARGET)-kern.o: $(OBJS) arch_lib $(OBJ_DIR)/$(TARGET_ARCH_DIR)/minios-$(MINIOS_TARGET_ARCH).lds
>  	$(LD) -r $(LDFLAGS) $(HEAD_OBJ) $(OBJS) $(LDARCHLIB) -o $@
> +	$(OBJCOPY) --dump-section .export_symbol=$(OBJ_DIR)/syms $@
>  
>  $(OBJ_DIR)/$(TARGET): $(OBJ_DIR)/$(TARGET)-kern.o $(APP_O)
>  	$(LD) -r $(LDFLAGS) $(OBJ_DIR)/$(TARGET)-kern.o $(APP_O) $(LDLIBS) -o $@.o
> -	$(OBJCOPY) -w -G $(GLOBAL_PREFIX)* -G _start $@.o $@.o
> +	$(OBJCOPY) -w -G $(GLOBAL_PREFIX)* -G _start --remove-section=.export_symbol $@.o $@.o
>  	$(LD) $(LDFLAGS) $(LDFLAGS_FINAL) $@.o $(EXTRA_OBJS) -o $@-debug
>  	strip -s $@-debug -o $@
>  	gzip -n -f -9 -c $@-debug >$@-debug.gz
> diff --git a/include/export.h b/include/export.h
> new file mode 100644
> index 00000000..7140ac68
> --- /dev/null
> +++ b/include/export.h
> @@ -0,0 +1,10 @@
> +#ifndef _EXPORT_H_
> +#define _EXPORT_H_
> +
> +/* Mark a symbol to be visible for apps and libs. */
> +#define EXPORT_SYMBOL(sym)          \
> +    asm(".section .export_symbol\n" \
> +        ".ascii \""#sym"\\n\"\n"    \
> +        ".previous\n")
> +
> +#endif /* _EXPORT_H_ */
> diff --git a/include/lib.h b/include/lib.h
> index dd68985a..abd4e9ab 100644
> --- a/include/lib.h
> +++ b/include/lib.h
> @@ -53,6 +53,7 @@
>  #include <stddef.h>
>  #include <xen/xen.h>
>  #include <xen/event_channel.h>
> +#include <mini-os/export.h>
>  #include "gntmap.h"
>  
>  #if __GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 6)
> -- 
> 2.35.3
>
diff mbox series

Patch

diff --git a/.gitignore b/.gitignore
index abef46b2..bacf787e 100644
--- a/.gitignore
+++ b/.gitignore
@@ -16,3 +16,4 @@  mini-os.gz
 minios-config.mk
 mini-os-debug
 mini-os-debug.gz
+syms
diff --git a/Makefile b/Makefile
index 85c6db75..588496cb 100644
--- a/Makefile
+++ b/Makefile
@@ -166,10 +166,11 @@  $(OBJ_DIR)/arch/x86/minios-x86%.lds:  arch/x86/minios-x86.lds.S
 
 $(OBJ_DIR)/$(TARGET)-kern.o: $(OBJS) arch_lib $(OBJ_DIR)/$(TARGET_ARCH_DIR)/minios-$(MINIOS_TARGET_ARCH).lds
 	$(LD) -r $(LDFLAGS) $(HEAD_OBJ) $(OBJS) $(LDARCHLIB) -o $@
+	$(OBJCOPY) --dump-section .export_symbol=$(OBJ_DIR)/syms $@
 
 $(OBJ_DIR)/$(TARGET): $(OBJ_DIR)/$(TARGET)-kern.o $(APP_O)
 	$(LD) -r $(LDFLAGS) $(OBJ_DIR)/$(TARGET)-kern.o $(APP_O) $(LDLIBS) -o $@.o
-	$(OBJCOPY) -w -G $(GLOBAL_PREFIX)* -G _start $@.o $@.o
+	$(OBJCOPY) -w -G $(GLOBAL_PREFIX)* -G _start --remove-section=.export_symbol $@.o $@.o
 	$(LD) $(LDFLAGS) $(LDFLAGS_FINAL) $@.o $(EXTRA_OBJS) -o $@-debug
 	strip -s $@-debug -o $@
 	gzip -n -f -9 -c $@-debug >$@-debug.gz
diff --git a/include/export.h b/include/export.h
new file mode 100644
index 00000000..7140ac68
--- /dev/null
+++ b/include/export.h
@@ -0,0 +1,10 @@ 
+#ifndef _EXPORT_H_
+#define _EXPORT_H_
+
+/* Mark a symbol to be visible for apps and libs. */
+#define EXPORT_SYMBOL(sym)          \
+    asm(".section .export_symbol\n" \
+        ".ascii \""#sym"\\n\"\n"    \
+        ".previous\n")
+
+#endif /* _EXPORT_H_ */
diff --git a/include/lib.h b/include/lib.h
index dd68985a..abd4e9ab 100644
--- a/include/lib.h
+++ b/include/lib.h
@@ -53,6 +53,7 @@ 
 #include <stddef.h>
 #include <xen/xen.h>
 #include <xen/event_channel.h>
+#include <mini-os/export.h>
 #include "gntmap.h"
 
 #if __GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 6)