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Commit ff7fbc72 authored by Suresh Siddha's avatar Suresh Siddha Committed by H. Peter Anvin
Browse files

x86, ptrace: Simplify xstateregs_get() 



48 bytes (bytes 464..511) of the xstateregs payload come from the
kernel defined structure (xstate_fx_sw_bytes). Rest comes from the
xstate regs structure in the thread struct. Instead of having multiple
user_regset_copyout()'s, simplify the xstateregs_get() by first
copying the SW bytes into the xstate regs structure in the thread structure
and then using one user_regset_copyout() to copyout the xstateregs.

Requested-by: default avatarRoland McGrath <roland@redhat.com>
Signed-off-by: default avatarSuresh Siddha <suresh.b.siddha@intel.com>
LKML-Reference: <20100222225240.494688491@sbs-t61.sc.intel.com>
Acked-by: default avatarRoland McGrath <roland@redhat.com>
Signed-off-by: default avatarH. Peter Anvin <hpa@zytor.com>
Cc: Oleg Nesterov <oleg@redhat.com>
parent c6a0dd7e

arch/x86/kernel/i387.c

+7 −23
Original line number Diff line number Diff line
@@ -243,34 +243,18 @@ int xstateregs_get(struct task_struct *target, const struct user_regset *regset, 
		return ret;



	/*

	 * First copy the fxsave bytes 0..463.

	 * Copy the 48bytes defined by the software first into the xstate

	 * memory layout in the thread struct, so that we can copy the entire

	 * xstateregs to the user using one user_regset_copyout().

	 */

	ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,

				  &target->thread.xstate->xsave, 0,

				  offsetof(struct user_xstateregs,

					   i387.xstate_fx_sw));

	if (ret)

		return ret;



	/*

	 * Copy the 48bytes defined by software.

	 */

	ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,

				  xstate_fx_sw_bytes,

				  offsetof(struct user_xstateregs,

					   i387.xstate_fx_sw),

				  offsetof(struct user_xstateregs,

					   xsave_hdr));

	if (ret)

		return ret;

	memcpy(&target->thread.xstate->fxsave.sw_reserved,

	       xstate_fx_sw_bytes, sizeof(xstate_fx_sw_bytes));



	/*

	 * Copy the rest of xstate memory layout.

	 * Copy the xstate memory layout.

	 */

	ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,

				  &target->thread.xstate->xsave.xsave_hdr,

				  offsetof(struct user_xstateregs,

					   xsave_hdr), -1);

				  &target->thread.xstate->xsave, 0, -1);

	return ret;

}