arm64/boot: Disable trapping of PMZR_EL0 writes to EL2grafted

__init_el2_fgt2() writes one mask to both HDFGRTR2_EL2 and HDFGWTR2_EL2.
PMZR_EL0 is write-only, so its trap bit, nPMZR_EL0, exists only in
HDFGWTR2_EL2 and is therefore never set: a PMZR_EL0 write from the host
traps to EL2, where the nVHE hypervisor has no handler and BUG()s. The
kernel never writes PMZR_EL0, but kernel.perf_user_access=1 has the PMU
driver set PMUSERENR_EL0.UEN for a task with a user-read event, so a
write from EL0 reaches the trap and takes the host down without a panic
message.

Accumulate the HDFGWTR2_EL2 bits separately, as __init_el2_fgt() already
does for HDFGWTR_EL2, and set nPMZR_EL0 with the other FEAT_PMUv3p9
bits.

Fixes: 858c7bfcb35e1 ("arm64/boot: Enable EL2 requirements for FEAT_PMUv3p9")
Cc: stable@vger.kernel.org
Signed-off-by: Fuad Tabba <fuad.tabba@linux.dev>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Reviewed-by: Oliver Upton <oupton@kernel.org>
Signed-off-by: Will Deacon <will@kernel.org>

1 files changed, 107 insertions, 0 deletions

diff --git a/include/math-emu/op-8.h b/include/math-emu/op-8.h
new file mode 100644
index 000000000..8b8c05eb8
--- /dev/null
+++ b/include/math-emu/op-8.h
@@ -0,0 +1,107 @@
+/* Software floating-point emulation.
+   Basic eight-word fraction declaration and manipulation.
+   Copyright (C) 1997,1998,1999 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contributed by Richard Henderson (rth@cygnus.com),
+		  Jakub Jelinek (jj@ultra.linux.cz) and
+		  Peter Maydell (pmaydell@chiark.greenend.org.uk).
+                                                         
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Library General Public License as
+   published by the Free Software Foundation; either version 2 of the
+   License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Library General Public License for more details.
+
+   You should have received a copy of the GNU Library General Public
+   License along with the GNU C Library; see the file COPYING.LIB.  If
+   not, write to the Free Software Foundation, Inc.,
+   59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
+
+#ifndef __MATH_EMU_OP_8_H__
+#define __MATH_EMU_OP_8_H__
+
+/* We need just a few things from here for op-4, if we ever need some
+   other macros, they can be added. */
+#define _FP_FRAC_DECL_8(X)	_FP_W_TYPE X##_f[8]
+#define _FP_FRAC_HIGH_8(X)	(X##_f[7])
+#define _FP_FRAC_LOW_8(X)	(X##_f[0])
+#define _FP_FRAC_WORD_8(X,w)	(X##_f[w])
+
+#define _FP_FRAC_SLL_8(X,N)						\
+  do {									\
+    _FP_I_TYPE _up, _down, _skip, _i;					\
+    _skip = (N) / _FP_W_TYPE_SIZE;					\
+    _up = (N) % _FP_W_TYPE_SIZE;					\
+    _down = _FP_W_TYPE_SIZE - _up;					\
+    if (!_up)								\
+      for (_i = 7; _i >= _skip; --_i)					\
+	X##_f[_i] = X##_f[_i-_skip];					\
+    else								\
+      {									\
+	for (_i = 7; _i > _skip; --_i)					\
+	  X##_f[_i] = X##_f[_i-_skip] << _up				\
+		      | X##_f[_i-_skip-1] >> _down;			\
+	X##_f[_i--] = X##_f[0] << _up; 					\
+      }									\
+    for (; _i >= 0; --_i)						\
+      X##_f[_i] = 0;							\
+  } while (0)
+
+#define _FP_FRAC_SRL_8(X,N)						\
+  do {									\
+    _FP_I_TYPE _up, _down, _skip, _i;					\
+    _skip = (N) / _FP_W_TYPE_SIZE;					\
+    _down = (N) % _FP_W_TYPE_SIZE;					\
+    _up = _FP_W_TYPE_SIZE - _down;					\
+    if (!_down)								\
+      for (_i = 0; _i <= 7-_skip; ++_i)					\
+	X##_f[_i] = X##_f[_i+_skip];					\
+    else								\
+      {									\
+	for (_i = 0; _i < 7-_skip; ++_i)				\
+	  X##_f[_i] = X##_f[_i+_skip] >> _down				\
+		      | X##_f[_i+_skip+1] << _up;			\
+	X##_f[_i++] = X##_f[7] >> _down;				\
+      }									\
+    for (; _i < 8; ++_i)						\
+      X##_f[_i] = 0;							\
+  } while (0)
+
+
+/* Right shift with sticky-lsb. 
+ * What this actually means is that we do a standard right-shift,
+ * but that if any of the bits that fall off the right hand side
+ * were one then we always set the LSbit.
+ */
+#define _FP_FRAC_SRS_8(X,N,size)					\
+  do {									\
+    _FP_I_TYPE _up, _down, _skip, _i;					\
+    _FP_W_TYPE _s;							\
+    _skip = (N) / _FP_W_TYPE_SIZE;					\
+    _down = (N) % _FP_W_TYPE_SIZE;					\
+    _up = _FP_W_TYPE_SIZE - _down;					\
+    for (_s = _i = 0; _i < _skip; ++_i)					\
+      _s |= X##_f[_i];							\
+    _s |= X##_f[_i] << _up;						\
+/* s is now != 0 if we want to set the LSbit */				\
+    if (!_down)								\
+      for (_i = 0; _i <= 7-_skip; ++_i)					\
+	X##_f[_i] = X##_f[_i+_skip];					\
+    else								\
+      {									\
+	for (_i = 0; _i < 7-_skip; ++_i)				\
+	  X##_f[_i] = X##_f[_i+_skip] >> _down				\
+		      | X##_f[_i+_skip+1] << _up;			\
+	X##_f[_i++] = X##_f[7] >> _down;				\
+      }									\
+    for (; _i < 8; ++_i)						\
+      X##_f[_i] = 0;							\
+    /* don't fix the LSB until the very end when we're sure f[0] is stable */	\
+    X##_f[0] |= (_s != 0);						\
+  } while (0)
+
+#endif