Add support for the extended FPU states on amd64, both for native

64bit and 32bit ABIs.  As a side-effect, it enables AVX on capable
CPUs.

In particular:

- Query the CPU support for XSAVE, list of the supported extensions
  and the required size of FPU save area. The hw.use_xsave tunable is
  provided for disabling XSAVE, and hw.xsave_mask may be used to
  select the enabled extensions.

- Remove the FPU save area from PCB and dynamically allocate the
  (run-time sized) user save area on the top of the kernel stack,
  right above the PCB. Reorganize the thread0 PCB initialization to
  postpone it after BSP is queried for save area size.

- The dumppcb, stoppcbs and susppcbs now do not carry the FPU state as
  well. FPU state is only useful for suspend, where it is saved in
  dynamically allocated suspfpusave area.

- Use XSAVE and XRSTOR to save/restore FPU state, if supported and
  enabled.

- Define new mcontext_t flag _MC_HASFPXSTATE, indicating that
  mcontext_t has a valid pointer to out-of-struct extended FPU
  state. Signal handlers are supplied with stack-allocated fpu
  state. The sigreturn(2) and setcontext(2) syscall honour the flag,
  allowing the signal handlers to inspect and manipilate extended
  state in the interrupted context.

- The getcontext(2) never returns extended state, since there is no
  place in the fixed-sized mcontext_t to place variable-sized save
  area. And, since mcontext_t is embedded into ucontext_t, makes it
  impossible to fix in a reasonable way.  Instead of extending
  getcontext(2) syscall, provide a sysarch(2) facility to query
  extended FPU state.

- Add ptrace(2) support for getting and setting extended state; while
  there, implement missed PT_I386_{GET,SET}XMMREGS for 32bit binaries.

- Change fpu_kern KPI to not expose struct fpu_kern_ctx layout to
  consumers, making it opaque. Internally, struct fpu_kern_ctx now
  contains a space for the extended state. Convert in-kernel consumers
  of fpu_kern KPI both on i386 and amd64.

First version of the support for AVX was submitted by Tim Bird
<tim.bird am sony com> on behalf of Sony. This version was written
from scratch.

Tested by:	pho (previous version), Yamagi Burmeister <lists yamagi org>
MFC after:	1 month

1 files changed, 12 insertions, 0 deletions

diff --git a/sys/amd64/include/sysarch.h b/sys/amd64/include/sysarch.h
index 7b95a8b..195d882 100644
--- a/sys/amd64/include/sysarch.h
+++ b/sys/amd64/include/sysarch.h
@@ -50,12 +50,14 @@
 #define	I386_SET_FSBASE		8
 #define	I386_GET_GSBASE		9
 #define	I386_SET_GSBASE		10
+#define	I386_GET_XFPUSTATE	11
 
 /* Leave space for 0-127 for to avoid translating syscalls */
 #define	AMD64_GET_FSBASE	128
 #define	AMD64_SET_FSBASE	129
 #define	AMD64_GET_GSBASE	130
 #define	AMD64_SET_GSBASE	131
+#define	AMD64_GET_XFPUSTATE	132
 
 struct i386_ldt_args {
 	unsigned int start;
@@ -69,6 +71,16 @@ struct i386_ioperm_args {
 	int	enable;
 };
 
+struct i386_get_xfpustate {
+	unsigned int addr;
+	int len;
+};
+
+struct amd64_get_xfpustate {
+	void *addr;
+	int len;
+};
+
 #ifndef _KERNEL
 __BEGIN_DECLS
 int amd64_get_fsbase(void **);