Messages in this thread | | | From | Charlemagne Lasse <> | Date | Tue, 2 Apr 2024 22:09:50 +0200 | Subject | Re: warning: cast removes address space '__percpu' of expression |
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Am Di., 2. Apr. 2024 um 11:53 Uhr schrieb Charlemagne Lasse <charlemagnelasse@gmail.com>: > > Am Di., 2. Apr. 2024 um 11:43 Uhr schrieb Uros Bizjak <ubizjak@gmail.com>: > [snip] > > Please try the attached patch that informs sparse about this action. > > I've tested it using > > ``` > git reset --hard v6.9-rc2 > patch -p1 -i ~/p.diff.txt > git clean -dfx > make allnoconfig -j$(nproc) > make kvm_guest.config > make prepare -j$(nproc) > touch include/linux/netdevice.h > make C=1 net/core/dev.o CHECK="sparse -Wcast-from-as" > ``` > > And it seems to work. Thanks
But I found another problem which seem to have been introduced by commit ed2f752e0e0a ("x86/percpu: Introduce const-qualified const_pcpu_hot to micro-optimize code generation")
``` git reset --hard ed2f752e0e0a21d941ca0ee539ef3d4cd576bc5e git cherry-pick 3a1d3829e193c091475ceab481c5f8deab385023 patch -p1 -i ~/p.diff.txt git clean -dfx make allnoconfig -j$(nproc) make kvm_guest.config echo CONFIG_MODULES=y >> .config echo CONFIG_NET_9P_VIRTIO=m >> .config make olddefconfig make prepare -j$(nproc) touch net/9p/trans_virtio.o make C=1 M=net/9p/ trans_virtio.o CHECK="sparse -Wconstexpr-not-const" ```
This now shows the warning:
``` net/9p/trans_virtio.c:831:1: warning: non-constant initializer for static object net/9p/trans_virtio.c:832:1: warning: non-constant initializer for static object ```
Which is from
``` module_init(p9_virtio_init); module_exit(p9_virtio_cleanup); ```
The same happens when directly switching to the mentioned commit:
``` git reset --hard ed2f752e0e0a21d941ca0ee539ef3d4cd576bc5e git cherry-pick 3a1d3829e193c091475ceab481c5f8deab385023 patch -p1 -i ~/p.diff.txt git clean -dfx make allnoconfig -j$(nproc) make kvm_guest.config echo CONFIG_MODULES=y >> .config echo CONFIG_NET_9P_VIRTIO=m >> .config make olddefconfig make prepare -j$(nproc) touch net/9p/trans_virtio.o make C=1 M=net/9p/ trans_virtio.o CHECK="sparse -Wconstexpr-not-const" ```
So something for module_init and module_exit changed with this commit. I can't see this when switching to a version before this commit:
``` git reset --hard ed2f752e0e0a21d941ca0ee539ef3d4cd576bc5e~1 git cherry-pick 3a1d3829e193c091475ceab481c5f8deab385023 git clean -dfx make allnoconfig -j$(nproc) make kvm_guest.config echo CONFIG_MODULES=y >> .config echo CONFIG_NET_9P_VIRTIO=m >> .config make olddefconfig make prepare -j$(nproc) touch net/9p/trans_virtio.o make C=1 M=net/9p/ trans_virtio.o CHECK="sparse -Wconstexpr-not-const" ```
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