Messages in this thread | | | Date | Wed, 17 Dec 2014 10:43:44 +0100 | From | Paolo Bonzini <> | Subject | Re: [PATCH 26/35] [PATCH 26/36] powerpc: Replace __get_cpu_var uses |
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On 16/12/2014 23:07, Alexander Graf wrote: > On 26.08.14 20:14, Tejun Heo wrote: >> On Sun, Aug 17, 2014 at 12:30:49PM -0500, Christoph Lameter wrote: >>> __get_cpu_var() is used for multiple purposes in the kernel source. One of >>> them is address calculation via the form &__get_cpu_var(x). This calculates >>> the address for the instance of the percpu variable of the current processor >>> based on an offset. >>> >>> Other use cases are for storing and retrieving data from the current >>> processors percpu area. __get_cpu_var() can be used as an lvalue when >>> writing data or on the right side of an assignment. >> ... >>> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> >>> CC: Paul Mackerras <paulus@samba.org> >>> Signed-off-by: Christoph Lameter <cl@linux.com> >> >> (Please disregard the ones I posted for v1 of the patch series) >> >> Applied to percpu/for-3.18-consistent-ops with the fix up patch rolled >> in. Please let me know if this patch should be routed differently. >> Note that this patch was to be applied to percpu/for-3.17 but delayed >> due to build issues caused by cpumask_var_t. > > Unfortunately this commit breaks e500v2 builds with KVM enabled: > > arch/powerpc/kvm/e500.c: In function "local_sid_setup_one": > arch/powerpc/kvm/e500.c:81:29: error: macro "__this_cpu_write" > requires 2 arguments, but only 1 given > arch/powerpc/kvm/e500.c:81:3: error: unknown type name "__this_cpu_write" > arch/powerpc/kvm/e500.c:81:47: error: expected "=", ",", ";", "asm" or > "__attribute__" before ")" token > arch/powerpc/kvm/e500.c:82:8: error: request for member "val" in > something not a structure or union > arch/powerpc/kvm/e500.c:83:8: error: request for member "pentry" in > something not a structure or union > > Looking at the offending line of code I'm not surprised: > > - __get_cpu_var(pcpu_sids).entry[sid] = entry; > + __this_cpu_write(pcpu_sids)entry[sid], entry); > > This doesn't quite look like valid C to me. The patch below fixes the > build error for me. Please check whether it's correct and if so apply it > directly to the tree.
I can also ask Linus to squash it in the merge.
Paolo
> > > Alex > > > From: Alexander Graf <agraf@suse.de> > Date: Tue, 16 Dec 2014 23:04:01 +0100 > Subject: [PATCH] KVM: PPC: E500: Compile fix in this_cpu_write > > Commit 69111bac42f5 (powerpc: Replace __get_cpu_var uses) introduced compile > breakage to the e500 target by introducing invalid automatically created C > syntax. > > Fix up the breakage and make the code compile again. > > Signed-off-by: Alexander Graf <agraf@suse.de> > > diff --git a/arch/powerpc/kvm/e500.c b/arch/powerpc/kvm/e500.c > index 1609584..e1cb588 100644 > --- a/arch/powerpc/kvm/e500.c > +++ b/arch/powerpc/kvm/e500.c > @@ -78,7 +78,7 @@ static inline int local_sid_setup_one(struct id *entry) > > sid = __this_cpu_inc_return(pcpu_last_used_sid); > if (sid < NUM_TIDS) { > - __this_cpu_write(pcpu_sids)entry[sid], entry); > + __this_cpu_write(pcpu_sids.entry[sid], entry); > entry->val = sid; > entry->pentry = this_cpu_ptr(&pcpu_sids.entry[sid]); > ret = sid; >
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