21a741eb75
kexec on pseries disables AIL (reloc_on_exc), required for scv
instruction support, before other CPUs have been shut down. This means
they can execute scv instructions after AIL is disabled, which causes an
interrupt at an unexpected entry location that crashes the kernel.
Change the kexec sequence to disable AIL after other CPUs have been
brought down.
As a refresher, the real-mode scv interrupt vector is 0x17000, and the
fixed-location head code probably couldn't easily deal with implementing
such high addresses so it was just decided not to support that interrupt
at all.
Fixes: 7fa95f9ada ("powerpc/64s: system call support for scv/rfscv instructions")
Cc: stable@vger.kernel.org # v5.9+
Reported-by: Sourabh Jain <sourabhjain@linux.ibm.com>
Closes: https://lore.kernel.org/3b4b2943-49ad-4619-b195-bc416f1d1409@linux.ibm.com
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Tested-by: Gautam Menghani <gautam@linux.ibm.com>
Tested-by: Sourabh Jain <sourabhjain@linux.ibm.com>
Link: https://msgid.link/20240625134047.298759-1-npiggin@gmail.com
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
63 lines
1.5 KiB
C
63 lines
1.5 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* Copyright 2006 Michael Ellerman, IBM Corporation
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*/
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#include <linux/kernel.h>
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#include <linux/interrupt.h>
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#include <asm/setup.h>
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#include <asm/page.h>
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#include <asm/firmware.h>
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#include <asm/kexec.h>
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#include <asm/xics.h>
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#include <asm/xive.h>
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#include <asm/smp.h>
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#include <asm/plpar_wrappers.h>
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#include "pseries.h"
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void pseries_kexec_cpu_down(int crash_shutdown, int secondary)
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{
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/*
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* Don't risk a hypervisor call if we're crashing
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* XXX: Why? The hypervisor is not crashing. It might be better
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* to at least attempt unregister to avoid the hypervisor stepping
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* on our memory.
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*/
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if (firmware_has_feature(FW_FEATURE_SPLPAR) && !crash_shutdown) {
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int ret;
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int cpu = smp_processor_id();
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int hwcpu = hard_smp_processor_id();
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if (get_lppaca()->dtl_enable_mask) {
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ret = unregister_dtl(hwcpu);
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if (ret) {
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pr_err("WARNING: DTL deregistration for cpu "
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"%d (hw %d) failed with %d\n",
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cpu, hwcpu, ret);
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}
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}
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ret = unregister_slb_shadow(hwcpu);
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if (ret) {
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pr_err("WARNING: SLB shadow buffer deregistration "
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"for cpu %d (hw %d) failed with %d\n",
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cpu, hwcpu, ret);
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}
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ret = unregister_vpa(hwcpu);
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if (ret) {
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pr_err("WARNING: VPA deregistration for cpu %d "
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"(hw %d) failed with %d\n", cpu, hwcpu, ret);
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}
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}
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if (xive_enabled()) {
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xive_teardown_cpu();
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if (!secondary)
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xive_shutdown();
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} else
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xics_kexec_teardown_cpu(secondary);
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}
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