On 24/10/2013 19:26, Jan Kiszka wrote :
On 2013-10-24 17:40, Jan Kiszka wrote:
On 2013-10-24 16:48, Gilles Chanteperdrix wrote:
On 10/24/2013 12:06 PM, Jan Kiszka wrote:
We
can, of course, replace the instructions with their obcodes (like the
kernel does), just makes the code more ugly.
Jan, please do this, even if it makes the code more ugly, it makes sense
for the 2.6.3 release to continue working with the tools it already
supported. No question for -forge, but we try hard to keep ABI
compatibility so that users can upgrade xenomai without even recompiling
their application, it does not make sense to suddenly stop working with
a toolchain which always worked before.
In fact, we already have legacy gas support: all these new instructions
are wrapped with CONFIG_AS_AVX, and only if that is set we use the new
assembler instructions. Given that this CONFIG has to be set based on
some test, something seems to go wrong in the kernel build over there.
But that's outside of the Xenomai scope. I'm currently trying to find
out if there was some related kernel issue back then.
OK, something likely went wrong in my brain back then while I tried to
make this build for all the combinations. I can't recall what those
CONFIG_X86_64 tests were for. This should build and in theory also work:
diff --git a/include/asm-x86/bits/pod.h b/include/asm-x86/bits/pod.h
index a32575f..c6fbcee 100644
--- a/include/asm-x86/bits/pod.h
+++ b/include/asm-x86/bits/pod.h
@@ -241,7 +241,7 @@ static inline void __save_i387(x86_fpustate *fpup)
{
#ifdef cpu_has_xsave
if (cpu_has_xsave) {
-#if defined(CONFIG_AS_AVX) || !defined CONFIG_X86_64
+#if defined(CONFIG_AS_AVX)
asm volatile("xsave" XSAVE_SUFFIX " %0"
: "=m" (fpup->xsave) : "a" (-1), "d" (-1)
: "memory");
@@ -301,7 +301,7 @@ static inline void __restore_i387(x86_fpustate *fpup)
{
#ifdef cpu_has_xsave
if (cpu_has_xsave) {
-#if defined(CONFIG_AS_AVX) || !defined(CONFIG_X86_64)
+#if defined(CONFIG_AS_AVX)
asm volatile("xrstor" XSAVE_SUFFIX " %0"
: : "m" (fpup->xsave), "a" (-1), "d" (-1)
: "memory");
Jean-Baptiste, do you happen to have an xsave-capable box at hand to
test this (/proc/cpuinfo shows the available features)? Xenomai's
switchtest will stress the code.
Thanks,
Jan
No, I do not have an xsave-capable box (no xsave or avx flag, only fxsr).
This patch works fine here.
Jean-Baptiste
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