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| author | Josh Poimboeuf <jpoimboe@redhat.com> | 2021-01-28 02:18:37 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-03-30 15:31:53 +0300 |
| commit | a63068e93917927d443e32609dde9298bcd14833 (patch) | |
| tree | a67bc7552e261fb2447b0e2f5ad69bafd033e0fc /include/asm-generic | |
| parent | 433cd7ca386c832a6e165d76f376c29dcac14fbb (diff) | |
| download | linux-a63068e93917927d443e32609dde9298bcd14833.tar.xz | |
static_call: Allow module use without exposing static_call_key
[ Upstream commit 73f44fe19d359635a607e8e8daa0da4001c1cfc2 ]
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
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'include/asm-generic')
| -rw-r--r-- | include/asm-generic/vmlinux.lds.h | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h index 34d8287cd774..d7efbc5490e8 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 |