Messages in this thread Patch in this message | | | Date | Thu, 03 Oct 2002 22:18:37 -0500 | From | Jordan Breeding <> | Subject | [PATCH] add devfs support to cpuid and msr |
| |
Hello,
This patch was originally floating around linux-kernel a while ago for 2.4.x, all I have done is update it to work with 2.5.x. It will only create directories and device files for cpus present at boot, there was a seperate version of a patch similar to this which implemented devfs_per_cpu_{un,}register functions but the devfs code it was based is very different than todays devfs in 2.5.x. This patch works well enough for me to simply gain access to /dev/cpu/%d/{cpuid,msr}. Thanks.
Jordan diff -urN linux-2.5.36/arch/i386/kernel/cpuid.c linux-2.5.36-bk/arch/i386/kernel/cpuid.c --- linux-2.5.36/arch/i386/kernel/cpuid.c 2002-08-27 23:21:23.000000000 -0500 +++ linux-2.5.36-bk/arch/i386/kernel/cpuid.c 2002-09-19 21:43:02.000000000 -0500 @@ -23,6 +23,8 @@ * * This driver uses /dev/cpu/%d/cpuid where %d is the minor number, and on * an SMP box will direct the access to CPU %d. + * + * 20020812 - David McIlwraith (quack@bigpond.net.au) - Added devfs support */ #include <linux/module.h> @@ -36,14 +38,17 @@ #include <linux/smp.h> #include <linux/major.h> #include <linux/fs.h> +#include <linux/devfs_fs_kernel.h> +#include <linux/slab.h> #include <linux/smp_lock.h> -#include <linux/fs.h> #include <asm/processor.h> #include <asm/msr.h> #include <asm/uaccess.h> #include <asm/system.h> +static devfs_handle_t *devfs_handles; + #ifdef CONFIG_SMP struct cpuid_command { @@ -113,7 +118,7 @@ u32 data[4]; size_t rv; u32 reg = *ppos; - int cpu = minor(file->f_dentry->d_inode->i_rdev); + int cpu = file->private_data ? (int) file->private_data - 1 : minor(file->f_dentry->d_inode->i_rdev); if ( count % 16 ) return -EINVAL; /* Invalid chunk size */ @@ -131,7 +136,7 @@ static int cpuid_open(struct inode *inode, struct file *file) { - int cpu = minor(file->f_dentry->d_inode->i_rdev); + int cpu = file->private_data ? (int) file->private_data - 1 : minor(file->f_dentry->d_inode->i_rdev); struct cpuinfo_x86 *c = &(cpu_data)[cpu]; if ( !(cpu_online_map & (1UL << cpu)) ) @@ -154,18 +159,41 @@ int __init cpuid_init(void) { - if (register_chrdev(CPUID_MAJOR, "cpu/cpuid", &cpuid_fops)) { + int i; + char devname[24]; + + if (register_chrdev(CPUID_MAJOR, "cpu/%d/cpuid", &cpuid_fops)) { printk(KERN_ERR "cpuid: unable to get major %d for cpuid\n", CPUID_MAJOR); return -EBUSY; } + devfs_handles = (devfs_handle_t *) kmalloc(num_online_cpus() * sizeof(devfs_handle_t), GFP_KERNEL); + if (!devfs_handles) { + printk(KERN_ERR "cpuid: unable to allocate memory for devfs\n"); + return -ENOMEM; + } + + for (i = 0; i < num_online_cpus(); ++i) + { + snprintf(devname, 24, "cpu/%i/cpuid", i); + devfs_handles[i] = devfs_register(NULL, devname, DEVFS_FL_DEFAULT, CPUID_MAJOR, i, + S_IFCHR | S_IRUGO, &cpuid_fops, (void *) i + 1); + } + return 0; } void __exit cpuid_exit(void) { - unregister_chrdev(CPUID_MAJOR, "cpu/cpuid"); + int i; + + unregister_chrdev(CPUID_MAJOR, "cpu/%d/cpuid"); + + for (i = 0; i < num_online_cpus(); ++i) + devfs_unregister(devfs_handles[i]); + + kfree(devfs_handles); } module_init(cpuid_init); diff -urN linux-2.5.36/arch/i386/kernel/msr.c linux-2.5.36-bk/arch/i386/kernel/msr.c --- linux-2.5.36/arch/i386/kernel/msr.c 2002-08-27 23:21:23.000000000 -0500 +++ linux-2.5.36-bk/arch/i386/kernel/msr.c 2002-09-19 21:45:06.000000000 -0500 @@ -22,6 +22,8 @@ * * This driver uses /dev/cpu/%d/msr where %d is the minor number, and on * an SMP box will direct the access to CPU %d. + * + * 20020812 - David McIlwraith (quack@bigpond.net.au) - Added devfs support */ #include <linux/module.h> @@ -35,6 +37,8 @@ #include <linux/smp.h> #include <linux/smp_lock.h> #include <linux/major.h> +#include <linux/devfs_fs_kernel.h> +#include <linux/slab.h> #include <linux/fs.h> #include <asm/processor.h> @@ -42,6 +46,8 @@ #include <asm/uaccess.h> #include <asm/system.h> +static devfs_handle_t *devfs_handles; + /* Note: "err" is handled in a funny way below. Otherwise one version of gcc or another breaks. */ @@ -186,7 +192,7 @@ u32 data[2]; size_t rv; u32 reg = *ppos; - int cpu = minor(file->f_dentry->d_inode->i_rdev); + int cpu = file->private_data ? (int) file->private_data - 1 : minor(file->f_dentry->d_inode->i_rdev); int err; if ( count % 8 ) @@ -211,7 +217,7 @@ u32 data[2]; size_t rv; u32 reg = *ppos; - int cpu = minor(file->f_dentry->d_inode->i_rdev); + int cpu = file->private_data ? (int) file->private_data - 1 : minor(file->f_dentry->d_inode->i_rdev); int err; if ( count % 8 ) @@ -231,7 +237,7 @@ static int msr_open(struct inode *inode, struct file *file) { - int cpu = minor(file->f_dentry->d_inode->i_rdev); + int cpu = file->private_data ? (int) file->private_data - 1 : minor(file->f_dentry->d_inode->i_rdev); struct cpuinfo_x86 *c = &(cpu_data)[cpu]; if ( !(cpu_online_map & (1UL << cpu)) ) @@ -255,18 +261,41 @@ int __init msr_init(void) { - if (register_chrdev(MSR_MAJOR, "cpu/msr", &msr_fops)) { + int i; + char devname[24]; + + if (register_chrdev(MSR_MAJOR, "cpu/%d/msr", &msr_fops)) { printk(KERN_ERR "msr: unable to get major %d for msr\n", MSR_MAJOR); return -EBUSY; } - + + devfs_handles = (devfs_handle_t *) kmalloc(num_online_cpus() * sizeof(devfs_handle_t), GFP_KERNEL); + if (!devfs_handles) { + printk(KERN_ERR "msr: unable to allocate memory for devfs\n"); + return -ENOMEM; + } + + for (i = 0; i < num_online_cpus(); ++i) + { + snprintf(devname, 24, "cpu/%i/msr", i); + devfs_handles[i] = devfs_register(NULL, devname, DEVFS_FL_DEFAULT, MSR_MAJOR, i, + S_IFCHR | S_IRUGO | S_IWUSR, &msr_fops, (void *) i + 1); + } + return 0; } void __exit msr_exit(void) { - unregister_chrdev(MSR_MAJOR, "cpu/msr"); + int i; + + unregister_chrdev(MSR_MAJOR, "cpu/%d/msr"); + + for (i = 0; i < num_online_cpus(); ++i) + devfs_unregister(devfs_handles[i]); + + kfree(devfs_handles); } module_init(msr_init); | |