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Message-Id: <1598287583-71762-7-git-send-email-mikelley@microsoft.com>
Date: Mon, 24 Aug 2020 09:46:19 -0700
From: Michael Kelley <mikelley@...rosoft.com>
To: will@...nel.org, ardb@...nel.org, arnd@...db.de,
catalin.marinas@....com, mark.rutland@....com, maz@...nel.org,
linux-arm-kernel@...ts.infradead.org, gregkh@...uxfoundation.org,
linux-kernel@...r.kernel.org, linux-hyperv@...r.kernel.org,
linux-efi@...r.kernel.org, linux-arch@...r.kernel.org,
wei.liu@...nel.org, vkuznets@...hat.com, kys@...rosoft.com
Cc: mikelley@...rosoft.com, sunilmut@...rosoft.com,
boqun.feng@...il.com
Subject: [PATCH v7 06/10] arm64: hyperv: Add kexec and panic handlers
Add functions to set up and remove kexec and panic
handlers, and to inform Hyper-V about a guest panic.
These functions are called from architecture independent
code in the VMbus driver.
This code is built only when CONFIG_HYPERV is enabled.
Signed-off-by: Michael Kelley <mikelley@...rosoft.com>
---
arch/arm64/hyperv/hv_core.c | 80 +++++++++++++++++++++++++++++++++++++++
arch/arm64/hyperv/mshyperv.c | 26 +++++++++++++
arch/arm64/include/asm/mshyperv.h | 2 +
3 files changed, 108 insertions(+)
diff --git a/arch/arm64/hyperv/hv_core.c b/arch/arm64/hyperv/hv_core.c
index 14e41b7..966d815 100644
--- a/arch/arm64/hyperv/hv_core.c
+++ b/arch/arm64/hyperv/hv_core.c
@@ -211,3 +211,83 @@ void hv_get_vpreg_128(u32 msr, struct hv_get_vp_registers_output *res)
kfree(output);
}
EXPORT_SYMBOL_GPL(hv_get_vpreg_128);
+
+
+/*
+ * hyperv_report_panic - report a panic to Hyper-V. This function uses
+ * the older version of the Hyper-V interface that admittedly doesn't
+ * pass enough information to be useful beyond just recording the
+ * occurrence of a panic. The parallel hyperv_report_panic_msg() uses the
+ * new interface that allows reporting 4 Kbytes of data, which is much
+ * more useful. Hyper-V on ARM64 always supports the newer interface, but
+ * we retain support for the older version because the sysadmin is allowed
+ * to disable the newer version via sysctl in case of information security
+ * concerns about the more verbose version.
+ */
+void hyperv_report_panic(struct pt_regs *regs, long err, bool in_die)
+{
+ static bool panic_reported;
+ u64 guest_id;
+
+ /* Don't report a panic to Hyper-V if we're not going to panic */
+ if (in_die && !panic_on_oops)
+ return;
+
+ /*
+ * We prefer to report panic on 'die' chain as we have proper
+ * registers to report, but if we miss it (e.g. on BUG()) we need
+ * to report it on 'panic'.
+ *
+ * Calling code in the 'die' and 'panic' paths ensures that only
+ * one CPU is running this code, so no atomicity is needed.
+ */
+ if (panic_reported)
+ return;
+ panic_reported = true;
+
+ guest_id = hv_get_vpreg(HV_REGISTER_GUEST_OSID);
+
+ /*
+ * Hyper-V provides the ability to store only 5 values.
+ * Pick the passed in error value, the guest_id, and the PC.
+ * The first two general registers are added arbitrarily.
+ */
+ hv_set_vpreg(HV_REGISTER_CRASH_P0, err);
+ hv_set_vpreg(HV_REGISTER_CRASH_P1, guest_id);
+ hv_set_vpreg(HV_REGISTER_CRASH_P2, regs->pc);
+ hv_set_vpreg(HV_REGISTER_CRASH_P3, regs->regs[0]);
+ hv_set_vpreg(HV_REGISTER_CRASH_P4, regs->regs[1]);
+
+ /*
+ * Let Hyper-V know there is crash data available
+ */
+ hv_set_vpreg(HV_REGISTER_CRASH_CTL, HV_CRASH_CTL_CRASH_NOTIFY);
+}
+EXPORT_SYMBOL_GPL(hyperv_report_panic);
+
+/*
+ * hyperv_report_panic_msg - report panic message to Hyper-V
+ * @pa: physical address of the panic page containing the message
+ * @size: size of the message in the page
+ */
+void hyperv_report_panic_msg(phys_addr_t pa, size_t size)
+{
+ /*
+ * P3 to contain the physical address of the panic page & P4 to
+ * contain the size of the panic data in that page. Rest of the
+ * registers are no-op when the NOTIFY_MSG flag is set.
+ */
+ hv_set_vpreg(HV_REGISTER_CRASH_P0, 0);
+ hv_set_vpreg(HV_REGISTER_CRASH_P1, 0);
+ hv_set_vpreg(HV_REGISTER_CRASH_P2, 0);
+ hv_set_vpreg(HV_REGISTER_CRASH_P3, pa);
+ hv_set_vpreg(HV_REGISTER_CRASH_P4, size);
+
+ /*
+ * Let Hyper-V know there is crash data available along with
+ * the panic message.
+ */
+ hv_set_vpreg(HV_REGISTER_CRASH_CTL,
+ (HV_CRASH_CTL_CRASH_NOTIFY | HV_CRASH_CTL_CRASH_NOTIFY_MSG));
+}
+EXPORT_SYMBOL_GPL(hyperv_report_panic_msg);
diff --git a/arch/arm64/hyperv/mshyperv.c b/arch/arm64/hyperv/mshyperv.c
index be2cd2f..5bd39cb 100644
--- a/arch/arm64/hyperv/mshyperv.c
+++ b/arch/arm64/hyperv/mshyperv.c
@@ -23,6 +23,8 @@
static void (*vmbus_handler)(void);
static void (*hv_stimer0_handler)(void);
+static void (*hv_kexec_handler)(void);
+static void (*hv_crash_handler)(struct pt_regs *regs);
static int vmbus_irq;
static long __percpu *vmbus_evt;
@@ -131,3 +133,27 @@ void hv_remove_stimer0_irq(int irq)
}
}
EXPORT_SYMBOL_GPL(hv_remove_stimer0_irq);
+
+void hv_setup_kexec_handler(void (*handler)(void))
+{
+ hv_kexec_handler = handler;
+}
+EXPORT_SYMBOL_GPL(hv_setup_kexec_handler);
+
+void hv_remove_kexec_handler(void)
+{
+ hv_kexec_handler = NULL;
+}
+EXPORT_SYMBOL_GPL(hv_remove_kexec_handler);
+
+void hv_setup_crash_handler(void (*handler)(struct pt_regs *regs))
+{
+ hv_crash_handler = handler;
+}
+EXPORT_SYMBOL_GPL(hv_setup_crash_handler);
+
+void hv_remove_crash_handler(void)
+{
+ hv_crash_handler = NULL;
+}
+EXPORT_SYMBOL_GPL(hv_remove_crash_handler);
diff --git a/arch/arm64/include/asm/mshyperv.h b/arch/arm64/include/asm/mshyperv.h
index 2ea64e54..5df96a5 100644
--- a/arch/arm64/include/asm/mshyperv.h
+++ b/arch/arm64/include/asm/mshyperv.h
@@ -149,6 +149,8 @@ static inline int hv_get_vector(void)
return vmbus_interrupt;
}
+#define hv_get_crash_ctl(val) \
+ (val = hv_get_vpreg(HV_REGISTER_CRASH_CTL))
/* SMCCC hypercall parameters */
#define HV_SMCCC_FUNC_NUMBER 1
--
1.8.3.1
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