| From 58d058f1fe1cc5981c57be8b48d3b2f74f25c0d6 Mon Sep 17 00:00:00 2001 |
| From: Jan Kiszka <jan.kiszka@siemens.com> |
| Date: Sun, 11 Sep 2016 23:30:04 +0200 |
| Subject: [PATCH] jailhouse: Add simple debug console via the hypervisor |
| |
| Jailhouse allows explicitly enabled cells to write character-wise |
| messages to the hypervisor debug console. Make use of this for a |
| platform-agnostic boot diagnosis channel, specifically for non-root |
| cells. This also comes with earlycon support. |
| |
| Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com> |
| (cherry picked from commit 60685bd589aef4972d20724863079edf2039eaa2) |
| From http://git.kiszka.org/?p=linux.git;a=shortlog;h=refs/heads/queues/jailhouse |
| --- |
| MAINTAINERS | 1 + |
| drivers/virt/Kconfig | 11 +++++ |
| drivers/virt/Makefile | 1 + |
| drivers/virt/jailhouse_dbgcon.c | 103 ++++++++++++++++++++++++++++++++++++++++ |
| 4 files changed, 116 insertions(+) |
| create mode 100644 drivers/virt/jailhouse_dbgcon.c |
| |
| --- a/MAINTAINERS |
| +++ b/MAINTAINERS |
| @@ -8773,6 +8773,7 @@ L: jailhouse-dev@googlegroups.com |
| S: Maintained |
| F: arch/x86/kernel/jailhouse.c |
| F: arch/x86/include/asm/jailhouse_para.h |
| +F: drivers/virt/jailhouse_dbgcon.c |
| |
| JC42.4 TEMPERATURE SENSOR DRIVER |
| M: Guenter Roeck <linux@roeck-us.net> |
| --- a/drivers/virt/Kconfig |
| +++ b/drivers/virt/Kconfig |
| @@ -31,5 +31,16 @@ config FSL_HV_MANAGER |
| 4) A kernel interface for receiving callbacks when a managed |
| partition shuts down. |
| |
| +config JAILHOUSE_DBGCON |
| + tristate "Jailhouse console driver" |
| + depends on X86 || ARM || ARM64 |
| + help |
| + The Jailhouse hypervisor provides a simple write-only console for |
| + debugging the bootstrap process of its cells. This driver registers |
| + a console with the kernel to make use of it. |
| + |
| + Note that Jailhouse has to be configured to permit a cell the usage |
| + of the console interface. |
| + |
| source "drivers/virt/vboxguest/Kconfig" |
| endif |
| --- a/drivers/virt/Makefile |
| +++ b/drivers/virt/Makefile |
| @@ -4,4 +4,5 @@ |
| # |
| |
| obj-$(CONFIG_FSL_HV_MANAGER) += fsl_hypervisor.o |
| +obj-$(CONFIG_JAILHOUSE_DBGCON) += jailhouse_dbgcon.o |
| obj-y += vboxguest/ |
| --- /dev/null |
| +++ b/drivers/virt/jailhouse_dbgcon.c |
| @@ -0,0 +1,103 @@ |
| +/* SPDX-License-Identifier: GPL-2.0 */ |
| +/* |
| + * Console driver for running over the Jailhouse partitioning hypervisor |
| + * |
| + * Copyright (c) Siemens AG, 2016-2018 |
| + * |
| + * Authors: |
| + * Jan Kiszka <jan.kiszka@siemens.com> |
| + */ |
| + |
| +#include <linux/console.h> |
| +#include <linux/hypervisor.h> |
| +#include <linux/module.h> |
| +#include <linux/serial_core.h> |
| +#ifdef CONFIG_X86 |
| +#include <asm/alternative.h> |
| +#endif |
| +#ifdef CONFIG_ARM |
| +#include <asm/opcodes-virt.h> |
| +#endif |
| + |
| +#define JAILHOUSE_HC_DEBUG_CONSOLE_PUTC 8 |
| + |
| +static void hypervisor_putc(char c) |
| +{ |
| +#if defined(CONFIG_X86) |
| + int result; |
| + |
| + asm volatile( |
| + ALTERNATIVE(".byte 0x0f,0x01,0xc1", ".byte 0x0f,0x01,0xd9", |
| + X86_FEATURE_VMMCALL) |
| + : "=a" (result) |
| + : "a" (JAILHOUSE_HC_DEBUG_CONSOLE_PUTC), "D" (c) |
| + : "memory"); |
| +#elif defined(CONFIG_ARM) |
| + register u32 num_res asm("r0") = JAILHOUSE_HC_DEBUG_CONSOLE_PUTC; |
| + register u32 arg1 asm("r1") = c; |
| + |
| + asm volatile( |
| + __HVC(0x4a48) |
| + : "=r" (num_res) |
| + : "r" (num_res), "r" (arg1) |
| + : "memory"); |
| +#elif defined(CONFIG_ARM64) |
| + register u64 num_res asm("x0") = JAILHOUSE_HC_DEBUG_CONSOLE_PUTC; |
| + register u64 arg1 asm("x1") = c; |
| + |
| + asm volatile( |
| + "hvc #0x4a48\n\t" |
| + : "=r" (num_res) |
| + : "r" (num_res), "r" (arg1) |
| + : "memory"); |
| +#else |
| +#error Unsupported architecture. |
| +#endif |
| +} |
| + |
| +static void jailhouse_dbgcon_write(struct console *con, const char *s, |
| + unsigned count) |
| +{ |
| + while (count > 0) { |
| + hypervisor_putc(*s); |
| + count--; |
| + s++; |
| + } |
| +} |
| + |
| +static int __init early_jailhouse_dbgcon_setup(struct earlycon_device *device, |
| + const char *options) |
| +{ |
| + device->con->write = jailhouse_dbgcon_write; |
| + return 0; |
| +} |
| + |
| +EARLYCON_DECLARE(jailhouse, early_jailhouse_dbgcon_setup); |
| + |
| +static struct console jailhouse_dbgcon = { |
| + .name = "jailhouse", |
| + .write = jailhouse_dbgcon_write, |
| + .flags = CON_PRINTBUFFER | CON_ANYTIME, |
| + .index = -1, |
| +}; |
| + |
| +static int __init jailhouse_dbgcon_init(void) |
| +{ |
| + if (!jailhouse_paravirt()) |
| + return -ENODEV; |
| + |
| + register_console(&jailhouse_dbgcon); |
| + return 0; |
| +} |
| + |
| +static void __exit jailhouse_dbgcon_exit(void) |
| +{ |
| + unregister_console(&jailhouse_dbgcon); |
| +} |
| + |
| +module_init(jailhouse_dbgcon_init); |
| +module_exit(jailhouse_dbgcon_exit); |
| + |
| +MODULE_LICENSE("GPL v2"); |
| +MODULE_DESCRIPTION("Jailhouse debug console driver"); |
| +MODULE_AUTHOR("Jan Kiszka <jan.kiszka@siemens.com>"); |