include/linux/compiler.h: fix Oops for Clang-compiled kernels

GCC unescapes escaped string section names while Clang does not. Because
__section uses the `#` stringification operator for the section name, it
doesn't need to be escaped.

This fixes an Oops observed in distro's that use systemd and not
net.core.bpf_jit_enable=1, when their kernels are compiled with Clang.

Link: https://github.com/ClangBuiltLinux/linux/issues/619
Link: https://bugs.llvm.org/show_bug.cgi?id=42950
Link: https://marc.info/?l=linux-netdev&m=156412960619946&w=2
Link: https://lore.kernel.org/lkml/20190904181740.GA19688@gmail.com/
Acked-by: Will Deacon <will@kernel.org>
Reported-by: Sedat Dilek <sedat.dilek@gmail.com>
Suggested-by: Josh Poimboeuf <jpoimboe@redhat.com>
Tested-by: Sedat Dilek <sedat.dilek@gmail.com>
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
[Cherry-picked from the __section cleanup series for 5.3]
[Adjusted commit message]
Signed-off-by: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>

diff --git a/include/linux/compiler.h b/include/linux/compiler.h
index f0fd5636fddbebd8a55d235dbd3cc8a41e398ae0..5e88e7e33abecd9ec88003b51fdd34ab611f6eb7 100644 (file)
--- a/include/linux/compiler.h
+++ b/include/linux/compiler.h
@@ -24,7 +24,7 @@ void ftrace_likely_update(struct ftrace_likely_data *f, int val,
                        long ______r;                                   \
                        static struct ftrace_likely_data                \
                                __aligned(4)                            \
-                               __section("_ftrace_annotated_branch")   \
+                               __section(_ftrace_annotated_branch)     \
                                ______f = {                             \
                                .data.func = __func__,                  \
                                .data.file = __FILE__,                  \
@@ -60,7 +60,7 @@ void ftrace_likely_update(struct ftrace_likely_data *f, int val,
 #define __trace_if_value(cond) ({                      \
        static struct ftrace_branch_data                \
                __aligned(4)                            \
-               __section("_ftrace_branch")             \
+               __section(_ftrace_branch)               \
                __if_trace = {                          \
                        .func = __func__,               \
                        .file = __FILE__,               \
@@ -118,7 +118,7 @@ void ftrace_likely_update(struct ftrace_likely_data *f, int val,
        ".popsection\n\t"
 
 /* Annotate a C jump table to allow objtool to follow the code flow */
-#define __annotate_jump_table __section(".rodata..c_jump_table")
+#define __annotate_jump_table __section(.rodata..c_jump_table)
 
 #else
 #define annotate_reachable()
@@ -298,7 +298,7 @@ unsigned long read_word_at_a_time(const void *addr)
  * visible to the compiler.
  */
 #define __ADDRESSABLE(sym) \
-       static void * __section(".discard.addressable") __used \
+       static void * __section(.discard.addressable) __used \
                __PASTE(__addressable_##sym, __LINE__) = (void *)&sym;
 
 /**