062dea906b
commit 08685be7761d69914f08c3d6211c543a385a5b9c upstream.
The L1D flush fallback functions are not recoverable vs interrupts,
yet the scv entry flush runs with MSR[EE]=1. This can result in a
timer (soft-NMI) or MCE or SRESET interrupt hitting here and overwriting
the EXRFI save area, which ends up corrupting userspace registers for
scv return.
Fix this by disabling RI and EE for the scv entry fallback flush.
Fixes: f79643787e ("powerpc/64s: flush L1D on kernel entry")
Cc: stable@vger.kernel.org # 5.9+ which also have flush L1D patch backport
Reported-by: Tulio Magno Quites Machado Filho <tuliom@linux.ibm.com>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210111062408.287092-1-npiggin@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
166 lines
4.0 KiB
C
166 lines
4.0 KiB
C
/* SPDX-License-Identifier: GPL-2.0-or-later */
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#ifndef _ASM_POWERPC_EXCEPTION_H
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#define _ASM_POWERPC_EXCEPTION_H
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/*
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* Extracted from head_64.S
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*
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* PowerPC version
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* Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
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*
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* Rewritten by Cort Dougan (cort@cs.nmt.edu) for PReP
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* Copyright (C) 1996 Cort Dougan <cort@cs.nmt.edu>
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* Adapted for Power Macintosh by Paul Mackerras.
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* Low-level exception handlers and MMU support
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* rewritten by Paul Mackerras.
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* Copyright (C) 1996 Paul Mackerras.
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*
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* Adapted for 64bit PowerPC by Dave Engebretsen, Peter Bergner, and
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* Mike Corrigan {engebret|bergner|mikejc}@us.ibm.com
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*
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* This file contains the low-level support and setup for the
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* PowerPC-64 platform, including trap and interrupt dispatch.
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*/
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/*
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* The following macros define the code that appears as
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* the prologue to each of the exception handlers. They
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* are split into two parts to allow a single kernel binary
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* to be used for pSeries and iSeries.
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*
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* We make as much of the exception code common between native
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* exception handlers (including pSeries LPAR) and iSeries LPAR
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* implementations as possible.
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*/
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#include <asm/feature-fixups.h>
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/* PACA save area size in u64 units (exgen, exmc, etc) */
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#define EX_SIZE 10
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/*
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* maximum recursive depth of MCE exceptions
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*/
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#define MAX_MCE_DEPTH 4
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#ifdef __ASSEMBLY__
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#define STF_ENTRY_BARRIER_SLOT \
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STF_ENTRY_BARRIER_FIXUP_SECTION; \
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nop; \
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nop; \
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nop
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#define STF_EXIT_BARRIER_SLOT \
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STF_EXIT_BARRIER_FIXUP_SECTION; \
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nop; \
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nop; \
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nop; \
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nop; \
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nop; \
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nop
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#define ENTRY_FLUSH_SLOT \
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ENTRY_FLUSH_FIXUP_SECTION; \
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nop; \
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nop; \
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nop;
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#define SCV_ENTRY_FLUSH_SLOT \
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SCV_ENTRY_FLUSH_FIXUP_SECTION; \
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nop; \
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nop; \
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nop;
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/*
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* r10 must be free to use, r13 must be paca
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*/
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#define INTERRUPT_TO_KERNEL \
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STF_ENTRY_BARRIER_SLOT; \
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ENTRY_FLUSH_SLOT
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/*
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* r10, ctr must be free to use, r13 must be paca
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*/
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#define SCV_INTERRUPT_TO_KERNEL \
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STF_ENTRY_BARRIER_SLOT; \
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SCV_ENTRY_FLUSH_SLOT
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/*
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* Macros for annotating the expected destination of (h)rfid
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*
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* The nop instructions allow us to insert one or more instructions to flush the
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* L1-D cache when returning to userspace or a guest.
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*
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* powerpc relies on return from interrupt/syscall being context synchronising
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* (which hrfid, rfid, and rfscv are) to support ARCH_HAS_MEMBARRIER_SYNC_CORE
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* without additional synchronisation instructions.
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*
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* soft-masked interrupt replay does not include a context-synchronising rfid,
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* but those always return to kernel, the sync is only required when returning
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* to user.
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*/
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#define RFI_FLUSH_SLOT \
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RFI_FLUSH_FIXUP_SECTION; \
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nop; \
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nop; \
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nop
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#define RFI_TO_KERNEL \
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rfid
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#define RFI_TO_USER \
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STF_EXIT_BARRIER_SLOT; \
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RFI_FLUSH_SLOT; \
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rfid; \
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b rfi_flush_fallback
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#define RFI_TO_USER_OR_KERNEL \
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STF_EXIT_BARRIER_SLOT; \
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RFI_FLUSH_SLOT; \
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rfid; \
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b rfi_flush_fallback
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#define RFI_TO_GUEST \
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STF_EXIT_BARRIER_SLOT; \
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RFI_FLUSH_SLOT; \
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rfid; \
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b rfi_flush_fallback
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#define HRFI_TO_KERNEL \
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hrfid
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#define HRFI_TO_USER \
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STF_EXIT_BARRIER_SLOT; \
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RFI_FLUSH_SLOT; \
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hrfid; \
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b hrfi_flush_fallback
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#define HRFI_TO_USER_OR_KERNEL \
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STF_EXIT_BARRIER_SLOT; \
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RFI_FLUSH_SLOT; \
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hrfid; \
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b hrfi_flush_fallback
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#define HRFI_TO_GUEST \
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STF_EXIT_BARRIER_SLOT; \
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RFI_FLUSH_SLOT; \
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hrfid; \
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b hrfi_flush_fallback
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#define HRFI_TO_UNKNOWN \
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STF_EXIT_BARRIER_SLOT; \
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RFI_FLUSH_SLOT; \
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hrfid; \
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b hrfi_flush_fallback
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#define RFSCV_TO_USER \
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STF_EXIT_BARRIER_SLOT; \
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RFI_FLUSH_SLOT; \
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RFSCV; \
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b rfscv_flush_fallback
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#else /* __ASSEMBLY__ */
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/* Prototype for function defined in exceptions-64s.S */
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void do_uaccess_flush(void);
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#endif /* __ASSEMBLY__ */
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#endif /* _ASM_POWERPC_EXCEPTION_H */
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