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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: Roland McGrath <roland@redhat.com>
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
LKML-Reference: <20100222225240.494688491@sbs-t61.sc.intel.com>
Acked-by: Roland McGrath <roland@redhat.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Cc: Oleg Nesterov <oleg@redhat.com>
This commit is contained in:
Suresh Siddha 2010-02-22 14:51:33 -08:00 committed by H. Peter Anvin
parent c6a0dd7ec6
commit ff7fbc72e0
1 changed files with 7 additions and 23 deletions
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30
arch/x86/kernel/i387.c
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@ -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;
memcpy(&target->thread.xstate->fxsave.sw_reserved,
xstate_fx_sw_bytes, sizeof(xstate_fx_sw_bytes));
/*
* Copy the 48bytes defined by software.
* Copy the xstate memory layout.
*/
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;
/*
* Copy the rest of 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;
}