linux-kernel - [PATCH 04/10] Drivers: hv: vmbus: Move hyperv_report_panic

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Date:   Wed, 27 Jan 2021 12:23:39 -0800
From:   Michael Kelley <mikelley@...rosoft.com>
To:     sthemmin@...rosoft.com, kys@...rosoft.com, wei.liu@...nel.org,
        tglx@...utronix.de, mingo@...hat.com, bp@...en8.de, hpa@...or.com,
        daniel.lezcano@...aro.org, arnd@...db.de,
        linux-hyperv@...r.kernel.org
Cc:     mikelley@...rosoft.com, linux-kernel@...r.kernel.org,
        x86@...nel.org, linux-arch@...r.kernel.org
Subject: [PATCH 04/10] Drivers: hv: vmbus: Move hyperv_report_panic_msg to arch neutral code

With the new Hyper-V MSR set function, hyperv_report_panic_msg() can be
architecture neutral, so move it out from under arch/x86 and merge into
hv_kmsg_dump(). This move also avoids needing a separate implementation
under arch/arm64.

No functional change.

Signed-off-by: Michael Kelley <mikelley@...rosoft.com>
---
 arch/x86/hyperv/hv_init.c      | 27 ---------------------------
 drivers/hv/vmbus_drv.c         | 24 +++++++++++++++++++-----
 include/asm-generic/mshyperv.h |  1 -
 3 files changed, 19 insertions(+), 33 deletions(-)

diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c
index 9b2cdbe..22e9557 100644
--- a/arch/x86/hyperv/hv_init.c
+++ b/arch/x86/hyperv/hv_init.c
@@ -452,33 +452,6 @@ void hyperv_report_panic(struct pt_regs *regs, long err, bool in_die)
 }
 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.
-	 */
-	wrmsrl(HV_X64_MSR_CRASH_P0, 0);
-	wrmsrl(HV_X64_MSR_CRASH_P1, 0);
-	wrmsrl(HV_X64_MSR_CRASH_P2, 0);
-	wrmsrl(HV_X64_MSR_CRASH_P3, pa);
-	wrmsrl(HV_X64_MSR_CRASH_P4, size);
-
-	/*
-	 * Let Hyper-V know there is crash data available along with
-	 * the panic message.
-	 */
-	wrmsrl(HV_X64_MSR_CRASH_CTL,
-	       (HV_CRASH_CTL_CRASH_NOTIFY | HV_CRASH_CTL_CRASH_NOTIFY_MSG));
-}
-EXPORT_SYMBOL_GPL(hyperv_report_panic_msg);
-
 bool hv_is_hyperv_initialized(void)
 {
 	union hv_x64_msr_hypercall_contents hypercall_msr;
diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
index 089f165..8affe68 100644
--- a/drivers/hv/vmbus_drv.c
+++ b/drivers/hv/vmbus_drv.c
@@ -1365,22 +1365,36 @@ static void hv_kmsg_dump(struct kmsg_dumper *dumper,
 			 enum kmsg_dump_reason reason)
 {
 	size_t bytes_written;
-	phys_addr_t panic_pa;
 
 	/* We are only interested in panics. */
 	if ((reason != KMSG_DUMP_PANIC) || (!sysctl_record_panic_msg))
 		return;
 
-	panic_pa = virt_to_phys(hv_panic_page);
-
 	/*
 	 * Write dump contents to the page. No need to synchronize; panic should
 	 * be single-threaded.
 	 */
 	kmsg_dump_get_buffer(dumper, false, hv_panic_page, HV_HYP_PAGE_SIZE,
 			     &bytes_written);
-	if (bytes_written)
-		hyperv_report_panic_msg(panic_pa, bytes_written);
+	if (!bytes_written)
+		return;
+	/*
+	 * 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_register(HV_REGISTER_CRASH_P0, 0);
+	hv_set_register(HV_REGISTER_CRASH_P1, 0);
+	hv_set_register(HV_REGISTER_CRASH_P2, 0);
+	hv_set_register(HV_REGISTER_CRASH_P3, virt_to_phys(hv_panic_page));
+	hv_set_register(HV_REGISTER_CRASH_P4, bytes_written);
+
+	/*
+	 * Let Hyper-V know there is crash data available along with
+	 * the panic message.
+	 */
+	hv_set_register(HV_REGISTER_CRASH_CTL,
+	       (HV_CRASH_CTL_CRASH_NOTIFY | HV_CRASH_CTL_CRASH_NOTIFY_MSG));
 }
 
 static struct kmsg_dumper hv_kmsg_dumper = {
diff --git a/include/asm-generic/mshyperv.h b/include/asm-generic/mshyperv.h
index 10c97a9..6a8072f 100644
--- a/include/asm-generic/mshyperv.h
+++ b/include/asm-generic/mshyperv.h
@@ -170,7 +170,6 @@ static inline int cpumask_to_vpset(struct hv_vpset *vpset,
 }
 
 void hyperv_report_panic(struct pt_regs *regs, long err, bool in_die);
-void hyperv_report_panic_msg(phys_addr_t pa, size_t size);
 bool hv_is_hyperv_initialized(void);
 bool hv_is_hibernation_supported(void);
 void hyperv_cleanup(void);
-- 
1.8.3.1