Messages in this thread | | | Date | Wed, 22 Apr 2015 11:45:05 -0700 | From | Dave Hansen <> | Subject | Re: [PATCH Bugfix v2 2/4] x86/xsaves: Define and use user_xstate_size for xstate size in signal context |
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On 04/21/2015 09:51 PM, Fenghua Yu wrote: > + /* > + * Copy rest of xstates in compact format to user. > + */ > + for (i = 2; i < xstate_features; i++) { > + if (test_bit(i, (unsigned long *)&pcntxt_mask)) { > + int user_offset, kernel_offset; > + int size; > + > + user_offset = xstate_offsets[i]; > + kernel_offset = xstate_comp_offsets[i]; > + size = xstate_sizes[i]; > + > + if (__copy_to_user(buf_fx + user_offset, > + xsave + kernel_offset, size)) > + return -1; > + } > + }
Is this checking the right bitmap?
The 'xsaves' documentation says: "If RFBM[i] = 1, XSTATE_BV[i] is set to the value of XINUSE[i]". Where "XINUSE denotes the state-component bitmap corresponding to the init optimization".
So shouldn't this be checking xsave->xsave_hdr.xstate_bv instead of pcntxt_mask? The will be equal unless the "init optimization" is in play.
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