Author: kib
Date: Thu Sep 18 09:13:20 2014
New Revision: 271747
URL: http://svnweb.freebsd.org/changeset/base/271747
Log:
- Use NULL instead of 0 for fpcurthread.
- Note the quirk with the interrupt enabled state of the dna handler.
- Use just panic() instead of printf() and panic(). Print tid instead
of pid, the fpu state is per-thread.
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Modified:
head/sys/amd64/amd64/fpu.c
Modified: head/sys/amd64/amd64/fpu.c
==============================================================================
--- head/sys/amd64/amd64/fpu.c Thu Sep 18 08:58:22 2014 (r271746)
+++ head/sys/amd64/amd64/fpu.c Thu Sep 18 09:13:20 2014 (r271747)
@@ -362,7 +362,7 @@ fpuexit(struct thread *td)
stop_emulating();
fpusave(curpcb->pcb_save);
start_emulating();
- PCPU_SET(fpcurthread, 0);
+ PCPU_SET(fpcurthread, NULL);
}
critical_exit();
}
@@ -602,16 +602,21 @@ fputrap_sse(void)
return (fpetable[(mxcsr & (~mxcsr >> 7)) & 0x3f]);
}
+static int err_count = 0;
+
/*
- * Implement device not available (DNA) exception
+ * Device Not Available (DNA, #NM) exception handler.
+ *
+ * It would be better to switch FP context here (if curthread !=
+ * fpcurthread) and not necessarily for every context switch, but it
+ * is too hard to access foreign pcb's.
*
- * It would be better to switch FP context here (if curthread != fpcurthread)
- * and not necessarily for every context switch, but it is too hard to
- * access foreign pcb's.
+ * The handler is entered with interrupts enabled, which allows the
+ * context switch to happen before critical enter() is executed, and
+ * causes restoration of FPU context on CPU other than that caused
+ * DNA. It is fine, since context switch started emulation on the
+ * current CPU as well.
*/
-
-static int err_count = 0;
-
void
fpudna(void)
{
@@ -625,11 +630,9 @@ fpudna(void)
return;
}
if (PCPU_GET(fpcurthread) != NULL) {
- printf("fpudna: fpcurthread = %p (%d), curthread = %p (%d)\n",
- PCPU_GET(fpcurthread),
- PCPU_GET(fpcurthread)->td_proc->p_pid,
- curthread, curthread->td_proc->p_pid);
- panic("fpudna");
+ panic("fpudna: fpcurthread = %p (%d), curthread = %p (%d)\n",
+ PCPU_GET(fpcurthread), PCPU_GET(fpcurthread)->td_tid,
+ curthread, curthread->td_tid);
}
stop_emulating();
/*
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