cfi: Drop __CFI_ADDRESSABLE

The __CFI_ADDRESSABLE macro is used for init_module and cleanup_module
to ensure we have the address of the CFI jump table, and with
CONFIG_X86_KERNEL_IBT to ensure LTO won't optimize away the symbols.
As __CFI_ADDRESSABLE is no longer necessary with -fsanitize=kcfi, add
a more flexible version of the __ADDRESSABLE macro and always ensure
these symbols won't be dropped.

Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Tested-by: Kees Cook <keescook@chromium.org>
Tested-by: Nathan Chancellor <nathan@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20220908215504.3686827-5-samitolvanen@google.com
This commit is contained in:
Sami Tolvanen 2022-09-08 14:54:46 -07:00 committed by Kees Cook
parent 9fca711582
commit 92efda8eb1
3 changed files with 6 additions and 24 deletions

View file

@ -221,9 +221,11 @@ void ftrace_likely_update(struct ftrace_likely_data *f, int val,
* otherwise, or eliminated entirely due to lack of references that are
* visible to the compiler.
*/
#define __ADDRESSABLE(sym) \
static void * __section(".discard.addressable") __used \
#define ___ADDRESSABLE(sym, __attrs) \
static void * __used __attrs \
__UNIQUE_ID(__PASTE(__addressable_,sym)) = (void *)&sym;
#define __ADDRESSABLE(sym) \
___ADDRESSABLE(sym, __section(".discard.addressable"))
/**
* offset_to_ptr - convert a relative memory offset to an absolute pointer