Messages in this thread | | | Date | Tue, 9 Nov 2021 20:42:29 +0100 | From | Peter Zijlstra <> | Subject | Re: [RFC PATCH 3/7] static_call: use helper to access non-exported key |
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On Tue, Nov 09, 2021 at 07:54:23PM +0100, Ard Biesheuvel wrote: > On Tue, 9 Nov 2021 at 19:53, Peter Zijlstra <peterz@infradead.org> wrote: > > > > On Tue, Nov 09, 2021 at 05:45:45PM +0100, Ard Biesheuvel wrote: > > > @@ -196,13 +190,21 @@ extern long __static_call_return0(void); > > > EXPORT_SYMBOL_GPL(STATIC_CALL_KEY(name)); \ > > > EXPORT_SYMBOL_GPL(STATIC_CALL_TRAMP(name)) > > > > > > +#define EXPORT_STATIC_CALL_GETKEY_HELPER(name) \ > > > + struct static_call_key *STATIC_CALL_GETKEY(name)(void) { \ > > > + BUG_ON(!core_kernel_text( \ > > > + (unsigned long)__builtin_return_address(0))); \ > > > + return &STATIC_CALL_KEY(name); \ > > > + } \ > > > + EXPORT_SYMBOL_GPL(STATIC_CALL_GETKEY(name)) > > > > So if I were a nevarious module, I would look up the above symbol from > > kallsyms (it is exported and easily obtainable) and then simply > > read the text to discover the key address and we're in business. > > > > Yeah I realised that. So would you prefer to have a > .static_call_tramp_key section in each module and look up the keys in > the module loader?
Think so... do you actually have a need for this?
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