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Subject[PATCH v6 06/10] arm64: hyperv: Add kexec and panic handlers
Date
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@microsoft.com>
---
arch/arm64/hyperv/hv_core.c | 61 ++++++++++++++++++++++++++++++++++++++++++++
arch/arm64/hyperv/mshyperv.c | 26 +++++++++++++++++++
2 files changed, 87 insertions(+)

diff --git a/arch/arm64/hyperv/hv_core.c b/arch/arm64/hyperv/hv_core.c
index 4aa6b8f..8d6de9f 100644
--- a/arch/arm64/hyperv/hv_core.c
+++ b/arch/arm64/hyperv/hv_core.c
@@ -199,3 +199,64 @@ void hv_get_vpreg_128(u32 msr, struct hv_get_vp_register_output *res)
kfree(output);
}
EXPORT_SYMBOL_GPL(hv_get_vpreg_128);
+
+void hyperv_report_panic(struct pt_regs *regs, long err)
+{
+ static bool panic_reported;
+ u64 guest_id;
+
+ /*
+ * 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'.
+ */
+ 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 ae6ece6..c58940d 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;
@@ -137,3 +139,27 @@ 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);
--
1.8.3.1
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