From 043327875298030095f9c5d04bd41def28275175 Mon Sep 17 00:00:00 2001 From: Thomas Weißschuh Date: Wed, 13 Mar 2024 19:19:30 +0100 Subject: misc/pvpanic: use bit macros MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The macros are easier to read. Suggested-by: Greg Kroah-Hartman Link: https://lore.kernel.org/lkml/2023110407-unselect-uptight-b96d@gregkh/ Signed-off-by: Thomas Weißschuh Link: https://lore.kernel.org/r/20240313-pvpanic-shutdown-header-v1-1-7f1970d66366@weissschuh.net Signed-off-by: Greg Kroah-Hartman --- include/uapi/misc/pvpanic.h | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) (limited to 'include/uapi') diff --git a/include/uapi/misc/pvpanic.h b/include/uapi/misc/pvpanic.h index 54b7485390d3..9ea6a965ca7a 100644 --- a/include/uapi/misc/pvpanic.h +++ b/include/uapi/misc/pvpanic.h @@ -3,7 +3,9 @@ #ifndef __PVPANIC_H__ #define __PVPANIC_H__ -#define PVPANIC_PANICKED (1 << 0) -#define PVPANIC_CRASH_LOADED (1 << 1) +#include + +#define PVPANIC_PANICKED _BITUL(0) +#define PVPANIC_CRASH_LOADED _BITUL(1) #endif /* __PVPANIC_H__ */ -- cgit v1.3 From ad76f3e8f57cef368fa98f2d4d8902ad66481a3e Mon Sep 17 00:00:00 2001 From: Thomas Weißschuh Date: Wed, 13 Mar 2024 19:19:31 +0100 Subject: misc/pvpanic: add shutdown event definition MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Shutdown requests are normally hardware dependent. By extending pvpanic to also handle shutdown requests, guests can submit such requests with an easily implementable and cross-platform mechanism. The event was added to the specification in qemu commit 73279cecca03 ("docs/specs/pvpanic: document shutdown event"). Signed-off-by: Thomas Weißschuh Acked-by: Arnd Bergmann Link: https://lore.kernel.org/r/20240313-pvpanic-shutdown-header-v1-2-7f1970d66366@weissschuh.net Signed-off-by: Greg Kroah-Hartman --- include/uapi/misc/pvpanic.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/uapi') diff --git a/include/uapi/misc/pvpanic.h b/include/uapi/misc/pvpanic.h index 9ea6a965ca7a..3f1745cd1b52 100644 --- a/include/uapi/misc/pvpanic.h +++ b/include/uapi/misc/pvpanic.h @@ -7,5 +7,6 @@ #define PVPANIC_PANICKED _BITUL(0) #define PVPANIC_CRASH_LOADED _BITUL(1) +#define PVPANIC_SHUTDOWN _BITUL(2) #endif /* __PVPANIC_H__ */ -- cgit v1.3 From b46271ec40a05580d55f917c9ac52cb93553160a Mon Sep 17 00:00:00 2001 From: Elizabeth Figura Date: Thu, 28 Mar 2024 19:05:53 -0500 Subject: ntsync: Introduce NTSYNC_IOC_CREATE_SEM. This corresponds to the NT syscall NtCreateSemaphore(). Semaphores are one of three types of object to be implemented in this driver, the others being mutexes and events. An NT semaphore contains a 32-bit counter, and is signaled and can be acquired when the counter is nonzero. The counter has a maximum value which is specified at creation time. The initial value of the semaphore is also specified at creation time. There are no restrictions on the maximum and initial value. Each object is exposed as an file, to which any number of fds may be opened. When all fds are closed, the object is deleted. Objects hold a pointer to the ntsync_device that created them. The device's reference count is driven by struct file. Signed-off-by: Elizabeth Figura Link: https://lore.kernel.org/r/20240329000621.148791-3-zfigura@codeweavers.com Signed-off-by: Greg Kroah-Hartman --- Documentation/userspace-api/ioctl/ioctl-number.rst | 2 + drivers/misc/ntsync.c | 131 +++++++++++++++++++++ include/uapi/linux/ntsync.h | 21 ++++ 3 files changed, 154 insertions(+) create mode 100644 include/uapi/linux/ntsync.h (limited to 'include/uapi') diff --git a/Documentation/userspace-api/ioctl/ioctl-number.rst b/Documentation/userspace-api/ioctl/ioctl-number.rst index c472423412bf..a141e8e65c5d 100644 --- a/Documentation/userspace-api/ioctl/ioctl-number.rst +++ b/Documentation/userspace-api/ioctl/ioctl-number.rst @@ -174,6 +174,8 @@ Code Seq# Include File Comments 'M' 00-0F drivers/video/fsl-diu-fb.h conflict! 'N' 00-1F drivers/usb/scanner.h 'N' 40-7F drivers/block/nvme.c +'N' 80-8F uapi/linux/ntsync.h NT synchronization primitives + 'O' 00-06 mtd/ubi-user.h UBI 'P' all linux/soundcard.h conflict! 'P' 60-6F sound/sscape_ioctl.h conflict! diff --git a/drivers/misc/ntsync.c b/drivers/misc/ntsync.c index bd76e653d83e..20158ec148bc 100644 --- a/drivers/misc/ntsync.c +++ b/drivers/misc/ntsync.c @@ -5,26 +5,157 @@ * Copyright (C) 2024 Elizabeth Figura */ +#include +#include #include #include #include +#include +#include #define NTSYNC_NAME "ntsync" +enum ntsync_type { + NTSYNC_TYPE_SEM, +}; + +/* + * Individual synchronization primitives are represented by + * struct ntsync_obj, and each primitive is backed by a file. + * + * The whole namespace is represented by a struct ntsync_device also + * backed by a file. + * + * Both rely on struct file for reference counting. Individual + * ntsync_obj objects take a reference to the device when created. + */ + +struct ntsync_obj { + enum ntsync_type type; + + union { + struct { + __u32 count; + __u32 max; + } sem; + } u; + + struct file *file; + struct ntsync_device *dev; +}; + +struct ntsync_device { + struct file *file; +}; + +static int ntsync_obj_release(struct inode *inode, struct file *file) +{ + struct ntsync_obj *obj = file->private_data; + + fput(obj->dev->file); + kfree(obj); + + return 0; +} + +static const struct file_operations ntsync_obj_fops = { + .owner = THIS_MODULE, + .release = ntsync_obj_release, + .llseek = no_llseek, +}; + +static struct ntsync_obj *ntsync_alloc_obj(struct ntsync_device *dev, + enum ntsync_type type) +{ + struct ntsync_obj *obj; + + obj = kzalloc(sizeof(*obj), GFP_KERNEL); + if (!obj) + return NULL; + obj->type = type; + obj->dev = dev; + get_file(dev->file); + + return obj; +} + +static int ntsync_obj_get_fd(struct ntsync_obj *obj) +{ + struct file *file; + int fd; + + fd = get_unused_fd_flags(O_CLOEXEC); + if (fd < 0) + return fd; + file = anon_inode_getfile("ntsync", &ntsync_obj_fops, obj, O_RDWR); + if (IS_ERR(file)) { + put_unused_fd(fd); + return PTR_ERR(file); + } + obj->file = file; + fd_install(fd, file); + + return fd; +} + +static int ntsync_create_sem(struct ntsync_device *dev, void __user *argp) +{ + struct ntsync_sem_args __user *user_args = argp; + struct ntsync_sem_args args; + struct ntsync_obj *sem; + int fd; + + if (copy_from_user(&args, argp, sizeof(args))) + return -EFAULT; + + if (args.count > args.max) + return -EINVAL; + + sem = ntsync_alloc_obj(dev, NTSYNC_TYPE_SEM); + if (!sem) + return -ENOMEM; + sem->u.sem.count = args.count; + sem->u.sem.max = args.max; + fd = ntsync_obj_get_fd(sem); + if (fd < 0) { + kfree(sem); + return fd; + } + + return put_user(fd, &user_args->sem); +} + static int ntsync_char_open(struct inode *inode, struct file *file) { + struct ntsync_device *dev; + + dev = kzalloc(sizeof(*dev), GFP_KERNEL); + if (!dev) + return -ENOMEM; + + file->private_data = dev; + dev->file = file; return nonseekable_open(inode, file); } static int ntsync_char_release(struct inode *inode, struct file *file) { + struct ntsync_device *dev = file->private_data; + + kfree(dev); + return 0; } static long ntsync_char_ioctl(struct file *file, unsigned int cmd, unsigned long parm) { + struct ntsync_device *dev = file->private_data; + void __user *argp = (void __user *)parm; + switch (cmd) { + case NTSYNC_IOC_CREATE_SEM: + return ntsync_create_sem(dev, argp); default: return -ENOIOCTLCMD; } diff --git a/include/uapi/linux/ntsync.h b/include/uapi/linux/ntsync.h new file mode 100644 index 000000000000..6a4867a6c97b --- /dev/null +++ b/include/uapi/linux/ntsync.h @@ -0,0 +1,21 @@ +/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */ +/* + * Kernel support for NT synchronization primitive emulation + * + * Copyright (C) 2021-2022 Elizabeth Figura + */ + +#ifndef __LINUX_NTSYNC_H +#define __LINUX_NTSYNC_H + +#include + +struct ntsync_sem_args { + __u32 sem; + __u32 count; + __u32 max; +}; + +#define NTSYNC_IOC_CREATE_SEM _IOWR('N', 0x80, struct ntsync_sem_args) + +#endif -- cgit v1.3 From dc806bd48abc1b8a4ae72709a37e65db42a32048 Mon Sep 17 00:00:00 2001 From: Elizabeth Figura Date: Thu, 28 Mar 2024 19:05:54 -0500 Subject: ntsync: Introduce NTSYNC_IOC_SEM_POST. This corresponds to the NT syscall NtReleaseSemaphore(). This increases the semaphore's internal counter by the given value, and returns the previous value. If the counter would overflow the defined maximum, the function instead fails and returns -EOVERFLOW. Signed-off-by: Elizabeth Figura Link: https://lore.kernel.org/r/20240329000621.148791-4-zfigura@codeweavers.com Signed-off-by: Greg Kroah-Hartman --- drivers/misc/ntsync.c | 72 +++++++++++++++++++++++++++++++++++++++++++-- include/uapi/linux/ntsync.h | 2 ++ 2 files changed, 71 insertions(+), 3 deletions(-) (limited to 'include/uapi') diff --git a/drivers/misc/ntsync.c b/drivers/misc/ntsync.c index 20158ec148bc..3c2f743c58b0 100644 --- a/drivers/misc/ntsync.c +++ b/drivers/misc/ntsync.c @@ -10,7 +10,9 @@ #include #include #include +#include #include +#include #include #define NTSYNC_NAME "ntsync" @@ -31,23 +33,70 @@ enum ntsync_type { */ struct ntsync_obj { + spinlock_t lock; + enum ntsync_type type; + struct file *file; + struct ntsync_device *dev; + + /* The following fields are protected by the object lock. */ union { struct { __u32 count; __u32 max; } sem; } u; - - struct file *file; - struct ntsync_device *dev; }; struct ntsync_device { struct file *file; }; +/* + * Actually change the semaphore state, returning -EOVERFLOW if it is made + * invalid. + */ +static int post_sem_state(struct ntsync_obj *sem, __u32 count) +{ + __u32 sum; + + lockdep_assert_held(&sem->lock); + + if (check_add_overflow(sem->u.sem.count, count, &sum) || + sum > sem->u.sem.max) + return -EOVERFLOW; + + sem->u.sem.count = sum; + return 0; +} + +static int ntsync_sem_post(struct ntsync_obj *sem, void __user *argp) +{ + __u32 __user *user_args = argp; + __u32 prev_count; + __u32 args; + int ret; + + if (copy_from_user(&args, argp, sizeof(args))) + return -EFAULT; + + if (sem->type != NTSYNC_TYPE_SEM) + return -EINVAL; + + spin_lock(&sem->lock); + + prev_count = sem->u.sem.count; + ret = post_sem_state(sem, args); + + spin_unlock(&sem->lock); + + if (!ret && put_user(prev_count, user_args)) + ret = -EFAULT; + + return ret; +} + static int ntsync_obj_release(struct inode *inode, struct file *file) { struct ntsync_obj *obj = file->private_data; @@ -58,9 +107,25 @@ static int ntsync_obj_release(struct inode *inode, struct file *file) return 0; } +static long ntsync_obj_ioctl(struct file *file, unsigned int cmd, + unsigned long parm) +{ + struct ntsync_obj *obj = file->private_data; + void __user *argp = (void __user *)parm; + + switch (cmd) { + case NTSYNC_IOC_SEM_POST: + return ntsync_sem_post(obj, argp); + default: + return -ENOIOCTLCMD; + } +} + static const struct file_operations ntsync_obj_fops = { .owner = THIS_MODULE, .release = ntsync_obj_release, + .unlocked_ioctl = ntsync_obj_ioctl, + .compat_ioctl = compat_ptr_ioctl, .llseek = no_llseek, }; @@ -75,6 +140,7 @@ static struct ntsync_obj *ntsync_alloc_obj(struct ntsync_device *dev, obj->type = type; obj->dev = dev; get_file(dev->file); + spin_lock_init(&obj->lock); return obj; } diff --git a/include/uapi/linux/ntsync.h b/include/uapi/linux/ntsync.h index 6a4867a6c97b..dcfa38fdc93c 100644 --- a/include/uapi/linux/ntsync.h +++ b/include/uapi/linux/ntsync.h @@ -18,4 +18,6 @@ struct ntsync_sem_args { #define NTSYNC_IOC_CREATE_SEM _IOWR('N', 0x80, struct ntsync_sem_args) +#define NTSYNC_IOC_SEM_POST _IOWR('N', 0x81, __u32) + #endif -- cgit v1.3