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 <[email protected]> >> CC: Paul Mackerras <[email protected]> >> Signed-off-by: Christoph Lameter <[email protected]> > > (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. Alex From: Alexander Graf <[email protected]> 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 <[email protected]> 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; -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
