Messages in this thread | | | From | Kees Cook <> | Date | Tue, 7 May 2019 09:16:29 -0700 | Subject | Re: [PATCH] latent_entropy: avoid build error when plugin cflags are not set |
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On Tue, May 7, 2019 at 7:28 AM Vasily Gorbik <gor@linux.ibm.com> wrote: > Some architectures set up CFLAGS for linux decompressor phase from > scratch and do not include GCC_PLUGINS_CFLAGS. Since "latent_entropy" > variable declaration is generated by the plugin code itself including > linux/random.h in decompressor code then would cause a build > error. E.g. on s390: > > In file included from ./include/linux/net.h:22, > from ./include/linux/skbuff.h:29, > from ./include/linux/if_ether.h:23, > from ./arch/s390/include/asm/diag.h:12, > from arch/s390/boot/startup.c:8: > ./include/linux/random.h: In function 'add_latent_entropy': > ./include/linux/random.h:26:39: error: 'latent_entropy' undeclared > (first use in this function); did you mean 'add_latent_entropy'? > 26 | add_device_randomness((const void *)&latent_entropy, > | ^~~~~~~~~~~~~~ > | add_latent_entropy > ./include/linux/random.h:26:39: note: each undeclared identifier is > reported only once for each function it appears in > > The build error is triggered by commit a80313ff91ab ("s390/kernel: > introduce .dma sections") which made it into 5.2 merge window. > > To address that avoid using CONFIG_GCC_PLUGIN_LATENT_ENTROPY in > favour of LATENT_ENTROPY_PLUGIN definition which is defined as a > part of gcc plugins cflags and hence reflect more accurately when gcc > plugin is active. Besides that it is also used for similar purpose in > linux/compiler-gcc.h for latent_entropy attribute definition. > > Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Thanks for fixing this! Do you want to take it via the s390 tree?
Acked-by: Kees Cook <keescook@chromium.org>
-Kees
> --- > include/linux/random.h | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/include/linux/random.h b/include/linux/random.h > index 445a0ea4ff49..d4eb9b3789ad 100644 > --- a/include/linux/random.h > +++ b/include/linux/random.h > @@ -20,7 +20,7 @@ struct random_ready_callback { > > extern void add_device_randomness(const void *, unsigned int); > > -#if defined(CONFIG_GCC_PLUGIN_LATENT_ENTROPY) && !defined(__CHECKER__) > +#if defined(LATENT_ENTROPY_PLUGIN) && !defined(__CHECKER__) > static inline void add_latent_entropy(void) > { > add_device_randomness((const void *)&latent_entropy, > -- > 2.18.0.13.gd42ae10 >
-- Kees Cook
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