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charset="utf-8" From: Khalid Aziz Reserve a range of ioctls for msharefs and add the first two ioctls to get and set the start address and size of an mshare region. Signed-off-by: Khalid Aziz Signed-off-by: Anthony Yznaga --- .../userspace-api/ioctl/ioctl-number.rst | 1 + include/uapi/linux/msharefs.h | 29 ++++++++ mm/mshare.c | 68 +++++++++++++++++++ 3 files changed, 98 insertions(+) create mode 100644 include/uapi/linux/msharefs.h diff --git a/Documentation/userspace-api/ioctl/ioctl-number.rst b/Documenta= tion/userspace-api/ioctl/ioctl-number.rst index 243f1f1b554a..aa22b5412e4d 100644 --- a/Documentation/userspace-api/ioctl/ioctl-number.rst +++ b/Documentation/userspace-api/ioctl/ioctl-number.rst @@ -303,6 +303,7 @@ Code Seq# Include File = Comments 'v' 20-27 arch/powerpc/include/uapi/asm/vas-api.h VAS API 'v' C0-FF linux/meye.h confl= ict! 'w' all CERN = SCI driver +'x' 00-1F linux/msharefs.h mshar= efs filesystem 'y' 00-1F packe= t based user level communications 'z' 00-3F CAN b= us card conflict! diff --git a/include/uapi/linux/msharefs.h b/include/uapi/linux/msharefs.h new file mode 100644 index 000000000000..c7b509c7e093 --- /dev/null +++ b/include/uapi/linux/msharefs.h @@ -0,0 +1,29 @@ +/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */ +/* + * msharefs defines a memory region that is shared across processes. + * ioctl is used on files created under msharefs to set various + * attributes on these shared memory regions + * + * + * Copyright (C) 2024 Oracle Corp. All rights reserved. + * Author: Khalid Aziz + */ + +#ifndef _UAPI_LINUX_MSHAREFS_H +#define _UAPI_LINUX_MSHAREFS_H + +#include +#include + +/* + * msharefs specific ioctl commands + */ +#define MSHAREFS_GET_SIZE _IOR('x', 0, struct mshare_info) +#define MSHAREFS_SET_SIZE _IOW('x', 1, struct mshare_info) + +struct mshare_info { + __u64 start; + __u64 size; +}; + +#endif diff --git a/mm/mshare.c b/mm/mshare.c index 060292fb6a00..056cb5a82547 100644 --- a/mm/mshare.c +++ b/mm/mshare.c @@ -10,24 +10,91 @@ * * Copyright (C) 2024 Oracle Corp. All rights reserved. * Author: Khalid Aziz + * Author: Matthew Wilcox * */ =20 #include #include +#include #include +#include =20 const unsigned long mshare_align =3D P4D_SIZE; =20 struct mshare_data { struct mm_struct *mm; + spinlock_t m_lock; + struct mshare_info minfo; }; =20 +static long +msharefs_set_size(struct mm_struct *host_mm, struct mshare_data *m_data, + struct mshare_info *minfo) +{ + /* + * Validate alignment for start address and size + */ + if (!minfo->size || ((minfo->start | minfo->size) & (mshare_align - 1))) { + spin_unlock(&m_data->m_lock); + return -EINVAL; + } + + host_mm->mmap_base =3D minfo->start; + host_mm->task_size =3D minfo->size; + + m_data->minfo.start =3D host_mm->mmap_base; + m_data->minfo.size =3D host_mm->task_size; + spin_unlock(&m_data->m_lock); + + return 0; +} + +static long +msharefs_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) +{ + struct mshare_data *m_data =3D filp->private_data; + struct mm_struct *host_mm =3D m_data->mm; + struct mshare_info minfo; + + switch (cmd) { + case MSHAREFS_GET_SIZE: + spin_lock(&m_data->m_lock); + minfo =3D m_data->minfo; + spin_unlock(&m_data->m_lock); + + if (copy_to_user((void __user *)arg, &minfo, sizeof(minfo))) + return -EFAULT; + + return 0; + + case MSHAREFS_SET_SIZE: + if (copy_from_user(&minfo, (struct mshare_info __user *)arg, + sizeof(minfo))) + return -EFAULT; + + /* + * If this mshare region has been set up once already, bail out + */ + spin_lock(&m_data->m_lock); + if (m_data->minfo.size !=3D 0) { + spin_unlock(&m_data->m_lock); + return -EINVAL; + } + + return msharefs_set_size(host_mm, m_data, &minfo); + + default: + return -ENOTTY; + } +} + static const struct inode_operations msharefs_dir_inode_ops; static const struct inode_operations msharefs_file_inode_ops; =20 static const struct file_operations msharefs_file_operations =3D { .open =3D simple_open, + .unlocked_ioctl =3D msharefs_ioctl, }; =20 static int @@ -51,6 +118,7 @@ msharefs_fill_mm(struct inode *inode) goto err_free; } m_data->mm =3D mm; + spin_lock_init(&m_data->m_lock); inode->i_private =3D m_data; =20 return 0; --=20 2.43.5