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authorSuresh Siddha <suresh.b.siddha@intel.com>2010-02-11 22:50:59 +0300
committerH. Peter Anvin <hpa@zytor.com>2010-02-12 02:08:17 +0300
commit5b3efd500854d45d305b53c54c97db5970959980 (patch)
tree731629e22791d14b9661cada9c0c69eb38776c3b /arch/x86/include/asm/user.h
parent676ad585531e965416fd958747894541dabcec96 (diff)
downloadlinux-5b3efd500854d45d305b53c54c97db5970959980.tar.xz
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>
Diffstat (limited to 'arch/x86/include/asm/user.h')
-rw-r--r--arch/x86/include/asm/user.h58
1 files changed, 58 insertions, 0 deletions
diff --git a/arch/x86/include/asm/user.h b/arch/x86/include/asm/user.h
index 999873b22e7f..24532c7da3d6 100644
--- a/arch/x86/include/asm/user.h
+++ b/arch/x86/include/asm/user.h
@@ -1,5 +1,63 @@
+#ifndef _ASM_X86_USER_H
+#define _ASM_X86_USER_H
+
#ifdef CONFIG_X86_32
# include "user_32.h"
#else
# include "user_64.h"
#endif
+
+#include <asm/types.h>
+
+struct user_ymmh_regs {
+ /* 16 * 16 bytes for each YMMH-reg */
+ __u32 ymmh_space[64];
+};
+
+struct user_xsave_hdr {
+ __u64 xstate_bv;
+ __u64 reserved1[2];
+ __u64 reserved2[5];
+};
+
+/*
+ * The structure layout of user_xstateregs, used for exporting the
+ * extended register state through ptrace and core-dump (NT_X86_XSTATE note)
+ * interfaces will be same as the memory layout of xsave used by the processor
+ * (except for the bytes 464..511, which can be used by the software) and hence
+ * the size of this structure varies depending on the features supported by the
+ * processor and OS. The size of the structure that users need to use can be
+ * obtained by doing:
+ * cpuid_count(0xd, 0, &eax, &ptrace_xstateregs_struct_size, &ecx, &edx);
+ * i.e., cpuid.(eax=0xd,ecx=0).ebx will be the size that user (debuggers, etc.)
+ * need to use.
+ *
+ * For now, only the first 8 bytes of the software usable bytes[464..471] will
+ * be used and will be set to OS enabled xstate mask (which is same as the
+ * 64bit mask returned by the xgetbv's xCR0). Users (analyzing core dump
+ * remotely, etc.) can use this mask as well as the mask saved in the
+ * xstate_hdr bytes and interpret what states the processor/OS supports
+ * and what states are in modified/initialized conditions for the
+ * particular process/thread.
+ *
+ * Also when the user modifies certain state FP/SSE/etc through the
+ * ptrace interface, they must ensure that the xsave_hdr.xstate_bv
+ * bytes[512..519] of the memory layout are updated correspondingly.
+ * i.e., for example when FP state is modified to a non-init state,
+ * xsave_hdr.xstate_bv's bit 0 must be set to '1', when SSE is modified to
+ * non-init state, xsave_hdr.xstate_bv's bit 1 must to be set to '1', etc.
+ */
+#define USER_XSTATE_FX_SW_WORDS 6
+#define USER_XSTATE_XCR0_WORD 0
+
+struct user_xstateregs {
+ struct {
+ __u64 fpx_space[58];
+ __u64 xstate_fx_sw[USER_XSTATE_FX_SW_WORDS];
+ } i387;
+ struct user_xsave_hdr xsave_hdr;
+ struct user_ymmh_regs ymmh;
+ /* further processor state extensions go here */
+};
+
+#endif /* _ASM_X86_USER_H */