The macro layer is efficient, but the exact syscall must be known at
the compilation stage. If a syscall number is kept in a variable macro
layer will not be able to resolve it to the syscall function.
For this case another file is generated - syscall_entry.c. Where
syscalls are resolved at run-time into a destination functions.
Signed-off-by: Yuri Volchkov <yuri.volchkov@xxxxxxxxx>
---
lib/syscall_shim/Makefile.uk | 10 ++++++-
lib/syscall_shim/entry.c.in_end | 15 ++++++++++
lib/syscall_shim/gen_entry.awk | 40 +++++++++++++++++++++++++++
lib/syscall_shim/include/uk/syscall.h | 2 ++
4 files changed, 66 insertions(+), 1 deletion(-)
create mode 100644 lib/syscall_shim/entry.c.in_end
create mode 100644 lib/syscall_shim/gen_entry.awk
diff --git a/lib/syscall_shim/Makefile.uk b/lib/syscall_shim/Makefile.uk
index 50ee28ca..4dcb3d69 100644
--- a/lib/syscall_shim/Makefile.uk
+++ b/lib/syscall_shim/Makefile.uk
@@ -7,7 +7,8 @@ LIBSYSCALL_SHIM_PHONY_SRC := $(addprefix
$(LIBSYSCALL_SHIM_INCLUDES_PATH)/, $(LI
LIBSYSCALL_SHIM_PHONY_SRC += $(LIBSYSCALL_SHIM_BUILD)/provided_syscalls.h.in
LIBSYSCALL_SHIM_PHONY_SRC_NEW := $(addsuffix .new,
$(LIBSYSCALL_SHIM_PHONY_SRC))
-LIBSYSCALL_SHIM_GEN_SRC := $(LIBSYSCALL_SHIM_INCLUDES_PATH)/provided_syscalls.h
+LIBSYSCALL_SHIM_GEN_SRC :=
$(LIBSYSCALL_SHIM_INCLUDES_PATH)/provided_syscalls.h \
+ $(LIBSYSCALL_SHIM_BUILD)/syscall_entry.c
UK_PREPARE-$(CONFIG_LIBSYSCALL_SHIM) += $(LIBSYSCALL_SHIM_PHONY_SRC) $(LIBSYSCALL_SHIM_GEN_SRC)
@@ -37,6 +38,11 @@ $(LIBSYSCALL_SHIM_INCLUDES_PATH)/provided_syscalls.h: $(LIBSYSCALL_SHIM_BUILD)/p
$(AWK) -F '-' -f $(LIBSYSCALL_SHIM_BASE)/gen_provided.awk \
$^ > $@)
+$(LIBSYSCALL_SHIM_BUILD)/syscall_entry.c: $(LIBSYSCALL_SHIM_BUILD)/provided_syscalls.h.in $(LIBSYSCALL_SHIM_BASE)/gen_entry.awk
+ $(call build_cmd,GEN,SYSCALL_SHIM,$(notdir $@), \
+ $(AWK) -F '-' -f $(LIBSYSCALL_SHIM_BASE)/gen_entry.awk $< > $@
&& \
+ cat $(LIBSYSCALL_SHIM_BASE)/entry.c.in_end >> $@)
+
$(LIBSYSCALL_SHIM_BUILD)/provided_syscalls.h.in.new:
$(call build_cmd,GEN,SYSCALL_SHIM,$(notdir $@), \
echo $(UK_PROVIDED_SYSCALLS-y) | tr ' ' '\n' > $@)
@@ -51,4 +57,6 @@ CXXINCLUDES-$(CONFIG_LIBSYSCALL_SHIM) +=
-I$(LIBSYSCALL_SHIM_BUILD)/include
CINCLUDES-y += -I$(LIBSYSCALL_SHIM_BASE)/include
CXXINCLUDES-y += -I$(LIBSYSCALL_SHIM_BASE)/include
+LIBSYSCALL_SHIM_SRCS-y += $(LIBSYSCALL_SHIM_BUILD)/syscall_entry.c
+
LIBSYSCALL_SHIM_CLEAN = $(LIBSYSCALL_SHIM_PHONY_SRC)
$(LIBSYSCALL_SHIM_PHONY_SRC_NEW) $(LIBSYSCALL_SHIM_GEN_SRC)
$(LIBSYSCALL_SHIM_GEN_SRC)
diff --git a/lib/syscall_shim/entry.c.in_end b/lib/syscall_shim/entry.c.in_end
new file mode 100644
index 00000000..dd809e7b
--- /dev/null
+++ b/lib/syscall_shim/entry.c.in_end
@@ -0,0 +1,15 @@
+
+long uk_syscall(long n, ...)
+{
+ va_list ap;
+ syscall_arg_t a,b,c,d,e,f;
+ va_start(ap, n);
+ a=va_arg(ap, long);
+ b=va_arg(ap, long);
+ c=va_arg(ap, long);
+ d=va_arg(ap, long);
+ e=va_arg(ap, long);
+ f=va_arg(ap, long);
+ va_end(ap);
+ return __syscall_dynamic(n,a,b,c,d,e,f);
+}
diff --git a/lib/syscall_shim/gen_entry.awk b/lib/syscall_shim/gen_entry.awk
new file mode 100644
index 00000000..92457089
--- /dev/null
+++ b/lib/syscall_shim/gen_entry.awk
@@ -0,0 +1,40 @@
+BEGIN {
+ max_args = 6
+ print "/* Auto generated file. DO NOT EDIT */\n\n"
+
+ print "#include <uk/syscall.h>"
+ print "#include <uk/print.h>\n"
+
+ printf "static inline long __syscall_dynamic(long nr, "
+ for (i = 1; i < max_args; i++)
+ printf "long arg%d, ",i
+ printf "long arg%d)\n{\n", max_args
+
+ for (i = 1; i <= max_args; i++)
+ printf "\t(void) arg%d;\n", i
+
+ print "\n\tswitch (nr) {"
+}
+
+
+/[a-zA-Z0-9]+-[0-9]+/{
+ name = $1
+ sys_name = "SYS_" name
+ uk_name = "uk_syscall_" name
+ args_nr = $2 + 0
+ printf "\tcase %s:\n", sys_name;
+ printf "\t\treturn %s(", uk_name;
+ for (i = 1; i < args_nr; i++)
+ printf("arg%d, ", i)
+ if (args_nr > 0)
+ printf("arg%d", args_nr)
+ printf(");\n")
+}
+
+END {
+ printf "\tdefault:\n"
+ printf "\t\tuk_pr_debug(\"syscall nr %%ld is not implemented\", nr);\n"
+ printf "\t\terrno = -ENOSYS;\n"
+ printf "\t\treturn -1;\n"
+ printf "\t}\n}\n"
+}
diff --git a/lib/syscall_shim/include/uk/syscall.h
b/lib/syscall_shim/include/uk/syscall.h
index 96811918..ebefa403 100644
--- a/lib/syscall_shim/include/uk/syscall.h
+++ b/lib/syscall_shim/include/uk/syscall.h
@@ -143,6 +143,8 @@ typedef long syscall_arg_t;
#include <uk/bits/provided_syscalls.h>
#include <uk/bits/syscall_stubs.h>
+long uk_syscall(long n, ...);
+
#define syscall(...) \
UK_CONCAT(__uk_syscall, __SYSCALL_NARGS(__VA_ARGS__))(__VA_ARGS__)
#endif
