x86/fpu: Hook up PKRU into ptrace()
One nice thing about having PKRU be XSAVE-managed is that it gets naturally exposed into the XSAVE-using ABIs. Now that XSAVE will not be used to manage PKRU, these ABIs need to be manually enabled to deal with PKRU. ptrace() uses copy_uabi_xstate_to_kernel() to collect the tracee's XSTATE. As PKRU is not in the task's XSTATE buffer, use task->thread.pkru for filling in up the ptrace buffer. Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Borislav Petkov <bp@suse.de> Link: https://lkml.kernel.org/r/20210623121456.508770763@linutronix.de
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@ -139,7 +139,7 @@ enum xstate_copy_mode {
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};
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struct membuf;
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void copy_xstate_to_uabi_buf(struct membuf to, struct xregs_state *xsave,
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void copy_xstate_to_uabi_buf(struct membuf to, struct task_struct *tsk,
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enum xstate_copy_mode mode);
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#endif
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@ -78,7 +78,7 @@ int xfpregs_get(struct task_struct *target, const struct user_regset *regset,
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sizeof(fpu->state.fxsave));
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}
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copy_xstate_to_uabi_buf(to, &fpu->state.xsave, XSTATE_COPY_FX);
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copy_xstate_to_uabi_buf(to, target, XSTATE_COPY_FX);
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return 0;
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}
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@ -126,14 +126,12 @@ int xfpregs_set(struct task_struct *target, const struct user_regset *regset,
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int xstateregs_get(struct task_struct *target, const struct user_regset *regset,
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struct membuf to)
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{
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struct fpu *fpu = &target->thread.fpu;
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if (!cpu_feature_enabled(X86_FEATURE_XSAVE))
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return -ENODEV;
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sync_fpstate(fpu);
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sync_fpstate(&target->thread.fpu);
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copy_xstate_to_uabi_buf(to, &fpu->state.xsave, XSTATE_COPY_XSAVE);
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copy_xstate_to_uabi_buf(to, target, XSTATE_COPY_XSAVE);
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return 0;
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}
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@ -336,7 +334,7 @@ int fpregs_get(struct task_struct *target, const struct user_regset *regset,
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struct membuf mb = { .p = &fxsave, .left = sizeof(fxsave) };
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/* Handle init state optimized xstate correctly */
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copy_xstate_to_uabi_buf(mb, &fpu->state.xsave, XSTATE_COPY_FP);
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copy_xstate_to_uabi_buf(mb, target, XSTATE_COPY_FP);
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fx = &fxsave;
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} else {
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fx = &fpu->state.fxsave;
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@ -962,7 +962,7 @@ static void copy_feature(bool from_xstate, struct membuf *to, void *xstate,
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/**
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* copy_xstate_to_uabi_buf - Copy kernel saved xstate to a UABI buffer
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* @to: membuf descriptor
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* @xsave: The kernel xstate buffer to copy from
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* @tsk: The task from which to copy the saved xstate
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* @copy_mode: The requested copy mode
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*
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* Converts from kernel XSAVE or XSAVES compacted format to UABI conforming
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@ -971,10 +971,11 @@ static void copy_feature(bool from_xstate, struct membuf *to, void *xstate,
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*
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* It supports partial copy but @to.pos always starts from zero.
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*/
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void copy_xstate_to_uabi_buf(struct membuf to, struct xregs_state *xsave,
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void copy_xstate_to_uabi_buf(struct membuf to, struct task_struct *tsk,
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enum xstate_copy_mode copy_mode)
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{
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const unsigned int off_mxcsr = offsetof(struct fxregs_state, mxcsr);
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struct xregs_state *xsave = &tsk->thread.fpu.state.xsave;
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struct xregs_state *xinit = &init_fpstate.xsave;
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struct xstate_header header;
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unsigned int zerofrom;
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@ -1048,11 +1049,21 @@ void copy_xstate_to_uabi_buf(struct membuf to, struct xregs_state *xsave,
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if (zerofrom < xstate_offsets[i])
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membuf_zero(&to, xstate_offsets[i] - zerofrom);
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copy_feature(header.xfeatures & BIT_ULL(i), &to,
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__raw_xsave_addr(xsave, i),
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__raw_xsave_addr(xinit, i),
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xstate_sizes[i]);
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if (i == XFEATURE_PKRU) {
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struct pkru_state pkru = {0};
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/*
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* PKRU is not necessarily up to date in the
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* thread's XSAVE buffer. Fill this part from the
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* per-thread storage.
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*/
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pkru.pkru = tsk->thread.pkru;
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membuf_write(&to, &pkru, sizeof(pkru));
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} else {
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copy_feature(header.xfeatures & BIT_ULL(i), &to,
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__raw_xsave_addr(xsave, i),
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__raw_xsave_addr(xinit, i),
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xstate_sizes[i]);
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}
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/*
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* Keep track of the last copied state in the non-compacted
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* target buffer for gap zeroing.
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