From mboxrd@z Thu Jan 1 00:00:00 1970 From: Michael Ellerman Subject: Re: [PATCH v2] of: Check for overlap in reserved memory regions Date: Tue, 10 Nov 2015 15:29:44 +1100 Message-ID: <1447129784.13889.25.camel@ellerman.id.au> References: <1442367036-15205-1-git-send-email-mitchelh@codeaurora.org> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1442367036-15205-1-git-send-email-mitchelh-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org> Sender: devicetree-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Mitchel Humpherys , Rob Herring , Frank Rowand , Grant Likely , devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Marek Szyprowski Cc: linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linuxppc-dev-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org List-Id: devicetree@vger.kernel.org On Tue, 2015-09-15 at 18:30 -0700, Mitchel Humpherys wrote: > Any overlap in the reserved memory regions (those specified in the > reserved-memory DT node) is a bug. These bugs might go undetected as > long as the contested region isn't used simultaneously by multiple > software agents, which makes such bugs hard to debug. Fix this by > printing a scary warning during boot if overlap is detected. > > diff --git a/drivers/of/of_reserved_mem.c b/drivers/of/of_reserved_mem.c > index 726ebe792813..62f467b8ccae 100644 > --- a/drivers/of/of_reserved_mem.c > +++ b/drivers/of/of_reserved_mem.c > @@ -197,12 +198,52 @@ static int __init __reserved_mem_init_node(struct reserved_mem *rmem) > return -ENOENT; > } > > +static int __init __rmem_cmp(const void *a, const void *b) > +{ > + const struct reserved_mem *ra = a, *rb = b; > + > + return ra->base - rb->base; > +} > + > +static void __init __rmem_check_for_overlap(void) > +{ > + int i; > + > + if (reserved_mem_count < 2) > + return; > + > + sort(reserved_mem, reserved_mem_count, sizeof(reserved_mem[0]), > + __rmem_cmp, NULL); > + for (i = 0; i < reserved_mem_count - 1; i++) { > + struct reserved_mem *this, *next; > + > + this = &reserved_mem[i]; > + next = &reserved_mem[i + 1]; > + if (!(this->base && next->base)) > + continue; > + if (this->base + this->size > next->base) { > + phys_addr_t this_end, next_end; > + > + this_end = this->base + this->size; > + next_end = next->base + next->size; > + WARN(1, > + "Reserved memory: OVERLAP DETECTED!\n%s (%pa--%pa) overlaps with %s (%pa--%pa)\n", > + this->name, &this->base, &this_end, > + next->name, &next->base, &next_end); This is blowing up on some powerpc machines. It's too early in boot to call WARN() on these systems. Can we turn it into a pr_err() for now? I'll send a patch? cheers -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html