[3/3] Add cache info for powerpc64
Commit Message
The actual cache info was added for 4.11, but have a guess at the
L1 linesizes using info provided by older kernels.
* sysdeps/unix/sysv/linux/powerpc/powerpc64/sysconf.c: New file.
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Steven Munroe <sjmunroe@us.ibm.com>
---
.../unix/sysv/linux/powerpc/powerpc64/sysconf.c | 90 ++++++++++++++++++++++
1 file changed, 90 insertions(+)
create mode 100644 sysdeps/unix/sysv/linux/powerpc/powerpc64/sysconf.c
Comments
On 06/09/2017 12:57 AM, Richard Henderson wrote:
> + case _SC_LEVEL1_ICACHE_SIZE:
> + return getauxval(AT_L1I_CACHESIZE);
Style (missing space) and potential namespace violation (should be
__getauxval).
Thanks,
Florian
Richard Henderson <rth@twiddle.net> writes:
> The actual cache info was added for 4.11, but have a guess at the
> L1 linesizes using info provided by older kernels.
>
> * sysdeps/unix/sysv/linux/powerpc/powerpc64/sysconf.c: New file.
There is already a patch reviewed and approved here:
https://patchwork.sourceware.org/patch/20202/
But this patch is blocked because it depends on another patch that's waiting
for review:
https://patchwork.sourceware.org/patch/20582/
On 06/09/2017 06:12 AM, Tulio Magno Quites Machado Filho wrote:
> Richard Henderson <rth@twiddle.net> writes:
>
>> The actual cache info was added for 4.11, but have a guess at the
>> L1 linesizes using info provided by older kernels.
>>
>> * sysdeps/unix/sysv/linux/powerpc/powerpc64/sysconf.c: New file.
>
> There is already a patch reviewed and approved here:
> https://patchwork.sourceware.org/patch/20202/
> +static long
> +auxv2sysconf (unsigned long type)
> +{
> + long rc;
> + rc = getauxval (type);
> + if (rc == 0)
> + {
> + __set_errno (EINVAL);
> + rc = -1;
> + }
> + return rc;
Setting EINVAL is wrong. That would imply that the _SC_* name supplied by the
caller is invalid somehow.
The return value should be 0 when the cache parameter is unknown, and -1 only
when it is known that the cache level does not exist.
You should be using __getauxval to match the hidden_proto...
>
> But this patch is blocked because it depends on another patch that's waiting
> for review:
> https://patchwork.sourceware.org/patch/20582/
>
... defined here. But this second patch does look right.
r~
new file mode 100644
@@ -0,0 +1,90 @@
+/* Copyright (C) 2017 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library. If not, see
+ <http://www.gnu.org/licenses/>. */
+
+#include <assert.h>
+#include <stdbool.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <sys/auxv.h>
+
+
+static long int linux_sysconf (int name);
+
+/* Get the value of the system variable NAME. */
+long int
+__sysconf (int name)
+{
+ unsigned long tmp;
+
+ /* The auxv entries describing the proper cache geometry were
+ added for kernel 4.11. Thankfully, getauxval returns 0 when
+ the entry isn't present and is also the return from sysconf
+ when the value is unknown.
+
+ For the L1 linesize names, when the proper auxv entries are
+ not present, we fall back on older auxv entries that provide
+ the "block" linesize used for cache flushing. It is a fair
+ guess that this does in fact correspond to the L1 shape. */
+ switch (name)
+ {
+ case _SC_LEVEL1_ICACHE_SIZE:
+ return getauxval(AT_L1I_CACHESIZE);
+ case _SC_LEVEL1_ICACHE_ASSOC:
+ return (getauxval(AT_L1I_CACHEGEOMETRY) >> 16) & 0xffff;
+ case _SC_LEVEL1_ICACHE_LINESIZE:
+ tmp = getauxval(AT_L1I_CACHEGEOMETRY);
+ if (tmp)
+ return tmp & 0xffff;
+ return getauxval(AT_ICACHEBSIZE);
+
+ case _SC_LEVEL1_DCACHE_SIZE:
+ return getauxval(AT_L1D_CACHESIZE);
+ case _SC_LEVEL1_DCACHE_ASSOC:
+ return (getauxval(AT_L1D_CACHEGEOMETRY) >> 16) & 0xffff;
+ case _SC_LEVEL1_DCACHE_LINESIZE:
+ tmp = getauxval(AT_L1D_CACHEGEOMETRY);
+ if (tmp)
+ return tmp & 0xffff;
+ return getauxval(AT_DCACHEBSIZE);
+
+ case _SC_LEVEL2_CACHE_SIZE:
+ return getauxval(AT_L2_CACHESIZE);
+ case _SC_LEVEL2_CACHE_ASSOC:
+ return (getauxval(AT_L2_CACHEGEOMETRY) >> 16) & 0xffff;
+ case _SC_LEVEL2_CACHE_LINESIZE:
+ return getauxval(AT_L2_CACHEGEOMETRY) & 0xffff;
+
+ case _SC_LEVEL3_CACHE_SIZE:
+ return getauxval(AT_L3_CACHESIZE);
+ case _SC_LEVEL3_CACHE_ASSOC:
+ return (getauxval(AT_L3_CACHEGEOMETRY) >> 16) & 0xffff;
+ case _SC_LEVEL3_CACHE_LINESIZE:
+ return getauxval(AT_L3_CACHEGEOMETRY) & 0xffff;
+
+ case _SC_LEVEL4_CACHE_SIZE:
+ case _SC_LEVEL4_CACHE_ASSOC:
+ case _SC_LEVEL4_CACHE_LINESIZE:
+ return 0;
+ }
+
+ return linux_sysconf (name);
+}
+
+/* Now the generic Linux version. */
+#undef __sysconf
+#define __sysconf static linux_sysconf
+#include <sysdeps/unix/sysv/linux/sysconf.c>