From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ralf Baechle Subject: Re: [PATCH] STAGING: Comedi: Build only on arches providing PAGE_KERNEL_NOCACHE Date: Thu, 23 Jun 2011 13:02:35 +0100 Message-ID: <20110623120234.GA22524@linux-mips.org> References: <20110623114536.GA14011@linux-mips.org> <4E032940.5010205@ge.com> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Return-path: Content-Disposition: inline In-Reply-To: <4E032940.5010205@ge.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: devel-bounces@linuxdriverproject.org Errors-To: devel-bounces@linuxdriverproject.org To: Martyn Welch Cc: devel@driverdev.osuosl.org, linux-m32r-ja@ml.linux-m32r.org, linux-m32r@ml.linux-m32r.org, Paul Mundt , linux-sh@vger.kernel.org, Benjamin Herrenschmidt , Greg Kroah-Hartman , linux-kernel@vger.kernel.org, Chris Metcalf , David Howells , linux-am33-list@redhat.com, Paul Mackerras , "H. Peter Anvin" , Thomas Gleixner , linux-arch@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, Ingo Molnar , x86@kernel.org List-Id: linux-arch.vger.kernel.org T24gVGh1LCBKdW4gMjMsIDIwMTEgYXQgMTI6NTM6MzZQTSArMDEwMCwgTWFydHluIFdlbGNoIHdy b3RlOgoKPiBPbiAyMy8wNi8xMSAxMjo0NSwgUmFsZiBCYWVjaGxlIHdyb3RlOgo+ID4gT24gYXJj aGl0ZWN0dXJlcyB0aGF0IGRvbid0IGRlZmluZSBQQUdFX0tFUk5FTF9OT0NBQ0hFLCB0aGUgQ29t ZWRpIGRyaXZlciB0dXJucwo+ID4gaW50byB0cmFnZWR5Ogo+ID4gCj4gPiAgIENDIFtNXSAgZHJp dmVycy9zdGFnaW5nL2NvbWVkaS9kcml2ZXJzLm8KPiA+IGRyaXZlcnMvc3RhZ2luZy9jb21lZGkv ZHJpdmVycy5jOiBJbiBmdW5jdGlvbiDigJhjb21lZGlfYnVmX2FsbG9j4oCZOgo+ID4gZHJpdmVy cy9zdGFnaW5nL2NvbWVkaS9kcml2ZXJzLmM6NTA1OjQxOiBlcnJvcjog4oCYUEFHRV9LRVJORUxf Tk9DQUNIReKAmSB1bmRlY2xhcmVkIChmaXJzdCB1c2UgaW4gdGhpcyBmdW5jdGlvbikKPiA+IGRy aXZlcnMvc3RhZ2luZy9jb21lZGkvZHJpdmVycy5jOjUwNTo0MTogbm90ZTogZWFjaCB1bmRlY2xh cmVkIGlkZW50aWZpZXIgaXMgcmVwIG9ydGVkIG9ubHkgb25jZSBmb3IgZWFjaCBmdW5jdGlvbiBp dCBhcHBlYXJzIGluCj4gPiBtYWtlWzNdOiAqKiogW2RyaXZlcnMvc3RhZ2luZy9jb21lZGkvZHJp dmVycy5vXSBFcnJvciAxCj4gPiAKPiA+IFJlc3RyaWN0IHRoZSBkcml2ZXIgdG8gb25seSB0aG9z ZSBhcmNoaXRlY3R1cmVzIHRoYXQgZGVmaW5lIFBBR0VfS0VSTkVMX05PQ0FDSEUuCj4gPiAKPiA+ IFBBR0VfS0VSTkVMX05PQ0FDSEUgaXMgYSBrbHVkZ2UgLSBzb21lIHN5c3RlbSBhcmNoaXRlY3R1 cmVzIHN1Y2ggYXMgU0dJIElQMjcKPiA+IGFyZSBldmVuIHVhYmxlIHRvIG9mZmVyIHVuY2FjaGVk IG9wZXJhdGlvbiAtIGF0IGxlYXN0IGluIHRoZSB3YXkgYW4gdW53aXR0aW5nCj4gPiBkcml2ZXIg bWlnaHQgYXNzdW1lLiAgSSBoYXZlbid0IGxvb2tlZCBpbiBkZXRhaWxzIGhvdyB0aGUgZHJpdmVy IGlzIHVzaW5nCj4gPiB0aGUgYXJlYSB2bWFwZWQgd2l0aCBQQUdFX0tFUk5FTF9OT0NBQ0hFIGJ1 dCBtYXliZSBkb2luZyBpdCBYRlMtc3R5bGUgdXNpbmcKPiA+IGNhY2hlZCBtZW1vcnkgYW5kIHRo ZSBmbHVzaF9rZXJuZWxfdm1hcF9yYW5nZSAvIGludmFsaWRhdGVfa2VybmVsX3ZtYXBfcmFuZ2UK PiA+IEFQSXMgaW4gY29uanVuY3Rpb24gd2l0aCB0aGUgRE1BIEFQSSBpcyBhIHByYWN0aWNhbCBh bHRlcm5hdGl2ZS4KPiA+IAo+ID4gU2lnbmVkLW9mZi1ieTogUmFsZiBCYWVjaGxlIDxyYWxmQGxp bnV4LW1pcHMub3JnPgo+ID4gCj4gPiAgZHJpdmVycy9zdGFnaW5nL2NvbWVkaS9LY29uZmlnIHwg ICAgMSArCj4gPiAgMSBmaWxlcyBjaGFuZ2VkLCAxIGluc2VydGlvbnMoKyksIDAgZGVsZXRpb25z KC0pCj4gPiAKPiA+IGRpZmYgLS1naXQgYS9kcml2ZXJzL3N0YWdpbmcvY29tZWRpL0tjb25maWcg Yi9kcml2ZXJzL3N0YWdpbmcvY29tZWRpL0tjb25maWcKPiA+IGluZGV4IDE1MDJkODAuLmJjY2Rj MTIgMTAwNjQ0Cj4gPiAtLS0gYS9kcml2ZXJzL3N0YWdpbmcvY29tZWRpL0tjb25maWcKPiA+ICsr KyBiL2RyaXZlcnMvc3RhZ2luZy9jb21lZGkvS2NvbmZpZwo+ID4gQEAgLTIsNiArMiw3IEBAIGNv bmZpZyBDT01FREkKPiA+ICAJdHJpc3RhdGUgIkRhdGEgYWNxdWlzaXRpb24gc3VwcG9ydCAoY29t ZWRpKSIKPiA+ICAJZGVmYXVsdCBOCj4gPiAgCWRlcGVuZHMgb24gbQo+ID4gKwlkZXBlbmRzIG9u IEJST0tFTiB8fCBGUlYgfHwgTTMyUiB8fCBNTjEwMzAwIHx8IFNVUEVSSCB8fCBUSUxFIHx8IFg4 Ngo+IAo+IEknbSBzdXJlIEkgZ290IGNvbWVkaSB0byBjb21waWxlIG9uIGEgMzItYml0IFBQQyBi b2FyZCBub3QgdGhhdCBsb25nIGFnby4gSGFzCj4gc29tZXRoaW5nIGNoYW5nZWQsIG9yIGlzIHRo aXMganVzdCBub3QgYW4gZXhoYXVzdGl2ZSBsaXN0PwoKKEFkZGluZyB0aGUgUFBDIGZvbGtzIHRv IGNjLikKCkEgImdpdCBncmVwIC13IFBBR0VfS0VSTkVMX05PQ0FDSEUgYXJjaC9wb3dlcnBjLyIg ZG9lc24ndCBmaW5kIGFueXRoaW5nIHNvCkkgZG9uJ3QgdGhpbmsgdGhlIGRyaXZlciB3aWxsIGJ1 aWxkIHRoZXJlLiAgSSBkb24ndCBoYXZlIGEgUFBDIHRvb2xjaGFpbgp0byB2ZXJpZnkgdGhhdC4K CiAgUmFsZgpfX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fXwpk ZXZlbCBtYWlsaW5nIGxpc3QKZGV2ZWxAbGludXhkcml2ZXJwcm9qZWN0Lm9yZwpodHRwOi8vZHJp dmVyZGV2LmxpbnV4ZHJpdmVycHJvamVjdC5vcmcvbWFpbG1hbi9saXN0aW5mby9kZXZlbAo= From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from h5.dl5rb.org.uk ([81.2.74.5]:47721 "EHLO duck.linux-mips.net" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753011Ab1FWMDk (ORCPT ); Thu, 23 Jun 2011 08:03:40 -0400 Date: Thu, 23 Jun 2011 13:02:35 +0100 From: Ralf Baechle Subject: Re: [PATCH] STAGING: Comedi: Build only on arches providing PAGE_KERNEL_NOCACHE Message-ID: <20110623120234.GA22524@linux-mips.org> References: <20110623114536.GA14011@linux-mips.org> <4E032940.5010205@ge.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <4E032940.5010205@ge.com> Sender: linux-arch-owner@vger.kernel.org List-ID: To: Martyn Welch Cc: Greg Kroah-Hartman , devel@driverdev.osuosl.org, linux-kernel@vger.kernel.org, David Howells , linux-m32r@ml.linux-m32r.org, linux-m32r-ja@ml.linux-m32r.org, linux-am33-list@redhat.com, Paul Mundt , linux-sh@vger.kernel.org, Chris Metcalf , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , x86@kernel.org, linux-arch@vger.kernel.org, Benjamin Herrenschmidt , Paul Mackerras , linuxppc-dev@lists.ozlabs.org Message-ID: <20110623120235.861JymRvvjYfMK7sO1F1JaOdzFgBhshqeHi5SJSN7vA@z> On Thu, Jun 23, 2011 at 12:53:36PM +0100, Martyn Welch wrote: > On 23/06/11 12:45, Ralf Baechle wrote: > > On architectures that don't define PAGE_KERNEL_NOCACHE, the Comedi driver turns > > into tragedy: > > > > CC [M] drivers/staging/comedi/drivers.o > > drivers/staging/comedi/drivers.c: In function ‘comedi_buf_alloc’: > > drivers/staging/comedi/drivers.c:505:41: error: ‘PAGE_KERNEL_NOCACHE’ undeclared (first use in this function) > > drivers/staging/comedi/drivers.c:505:41: note: each undeclared identifier is rep orted only once for each function it appears in > > make[3]: *** [drivers/staging/comedi/drivers.o] Error 1 > > > > Restrict the driver to only those architectures that define PAGE_KERNEL_NOCACHE. > > > > PAGE_KERNEL_NOCACHE is a kludge - some system architectures such as SGI IP27 > > are even uable to offer uncached operation - at least in the way an unwitting > > driver might assume. I haven't looked in details how the driver is using > > the area vmaped with PAGE_KERNEL_NOCACHE but maybe doing it XFS-style using > > cached memory and the flush_kernel_vmap_range / invalidate_kernel_vmap_range > > APIs in conjunction with the DMA API is a practical alternative. > > > > Signed-off-by: Ralf Baechle > > > > drivers/staging/comedi/Kconfig | 1 + > > 1 files changed, 1 insertions(+), 0 deletions(-) > > > > diff --git a/drivers/staging/comedi/Kconfig b/drivers/staging/comedi/Kconfig > > index 1502d80..bccdc12 100644 > > --- a/drivers/staging/comedi/Kconfig > > +++ b/drivers/staging/comedi/Kconfig > > @@ -2,6 +2,7 @@ config COMEDI > > tristate "Data acquisition support (comedi)" > > default N > > depends on m > > + depends on BROKEN || FRV || M32R || MN10300 || SUPERH || TILE || X86 > > I'm sure I got comedi to compile on a 32-bit PPC board not that long ago. Has > something changed, or is this just not an exhaustive list? (Adding the PPC folks to cc.) A "git grep -w PAGE_KERNEL_NOCACHE arch/powerpc/" doesn't find anything so I don't think the driver will build there. I don't have a PPC toolchain to verify that. Ralf