x86, ptrace: regset extensions to support xstate

Add the xstate regset support which helps extend the kernel ptrace and the
core-dump interfaces to support AVX state etc.

This regset interface is designed to support all the future state that gets
supported using xsave/xrstor infrastructure.

Looking at the memory layout saved by "xsave", one can't say which state
is represented in the memory layout. This is because if a particular state is
in init state, in the xsave hdr it can be represented by bit '0'. And hence
we can't really say by the xsave header wether a state is in init state or
the state is not saved in the memory layout.

And hence the xsave memory layout available through this regset
interface uses SW usable bytes [464..511] to convey what state is represented
in the memory layout.

First 8 bytes of the sw_usable_bytes[464..467] will be set to OS enabled xstate
mask(which is same as the 64bit mask returned by the xgetbv's xCR0).

The note NT_X86_XSTATE represents the extended state information in the
core file, using the above mentioned memory layout.

Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
LKML-Reference: <20100211195614.802495327@sbs-t61.sc.intel.com>
Signed-off-by: Hongjiu Lu <hjl.tools@gmail.com>
Cc: Roland McGrath <roland@redhat.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/include/linux/elf.h b/include/linux/elf.h
index 0cc4d55151b7..a8c4af073ce9 100644
--- a/include/linux/elf.h
+++ b/include/linux/elf.h
@@ -361,6 +361,7 @@ typedef struct elf64_shdr {
 #define NT_PPC_VSX      0x102           /* PowerPC VSX registers */
 #define NT_386_TLS      0x200           /* i386 TLS slots (struct user_desc) */
 #define NT_386_IOPERM   0x201           /* x86 io permission bitmap (1=deny) */
+#define NT_X86_XSTATE   0x202           /* x86 extended state using xsave */
 #define NT_S390_HIGH_GPRS       0x300   /* s390 upper register halves */