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authorJosh Poimboeuf <jpoimboe@redhat.com>2021-01-27 17:18:37 -0600
committerIngo Molnar <mingo@kernel.org>2021-02-17 14:12:42 +0100
commit73f44fe19d359635a607e8e8daa0da4001c1cfc2 (patch)
tree5b4c6bf010e5595ea2cd2314c239ef47503b84b0 /include/asm-generic
parente59e10f8ef63d42fbb99776a5a112841e798b3b5 (diff)
static_call: Allow module use without exposing static_call_key
When exporting static_call_key; with EXPORT_STATIC_CALL*(), the module can use static_call_update() to change the function called. This is not desirable in general. Not exporting static_call_key however also disallows usage of static_call(), since objtool needs the key to construct the static_call_site. Solve this by allowing objtool to create the static_call_site using the trampoline address when it builds a module and cannot find the static_call_key symbol. The module loader will then try and map the trampole back to a key before it constructs the normal sites list. Doing this requires a trampoline -> key associsation, so add another magic section that keeps those. Originally-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lkml.kernel.org/r/20210127231837.ifddpn7rhwdaepiu@treble
Diffstat (limited to 'include/asm-generic')
-rw-r--r--include/asm-generic/vmlinux.lds.h5
1 files changed, 4 insertions, 1 deletions
diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h
index b97c628ad91f..3f747de1934d 100644
--- a/include/asm-generic/vmlinux.lds.h
+++ b/include/asm-generic/vmlinux.lds.h
@@ -393,7 +393,10 @@
. = ALIGN(8); \
__start_static_call_sites = .; \
KEEP(*(.static_call_sites)) \
- __stop_static_call_sites = .;
+ __stop_static_call_sites = .; \
+ __start_static_call_tramp_key = .; \
+ KEEP(*(.static_call_tramp_key)) \
+ __stop_static_call_tramp_key = .;
/*
* Allow architectures to handle ro_after_init data on their