diff options
| -rw-r--r-- | Documentation/kernel-parameters.txt | 3 | ||||
| -rw-r--r-- | drivers/char/Kconfig | 10 | ||||
| -rw-r--r-- | drivers/char/hpet.c | 24 |
3 files changed, 33 insertions, 4 deletions
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index 882a40d405c8..9ca3e74a10e1 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -1070,6 +1070,9 @@ bytes respectively. Such letter suffixes can also be entirely omitted. VIA, nVidia) verbose: show contents of HPET registers during setup + hpet_mmap= [X86, HPET_MMAP] Allow userspace to mmap HPET + registers. Default set by CONFIG_HPET_MMAP_DEFAULT. + hugepages= [HW,X86-32,IA-64] HugeTLB pages to allocate at boot. hugepagesz= [HW,IA-64,PPC,X86-64] The size of the HugeTLB pages. On x86-64 and powerpc, this option can be specified diff --git a/drivers/char/Kconfig b/drivers/char/Kconfig index 14219972c745..fa3243d71c76 100644 --- a/drivers/char/Kconfig +++ b/drivers/char/Kconfig @@ -522,10 +522,16 @@ config HPET_MMAP If you say Y here, user applications will be able to mmap the HPET registers. +config HPET_MMAP_DEFAULT + bool "Enable HPET MMAP access by default" + default y + depends on HPET_MMAP + help In some hardware implementations, the page containing HPET registers may also contain other things that shouldn't be - exposed to the user. If this applies to your hardware, - say N here. + exposed to the user. This option selects the default (if + kernel parameter hpet_mmap is not set) user access to the + registers for applications that require it. config HANGCHECK_TIMER tristate "Hangcheck timer" diff --git a/drivers/char/hpet.c b/drivers/char/hpet.c index dca5834685cf..5d9c31dfc905 100644 --- a/drivers/char/hpet.c +++ b/drivers/char/hpet.c @@ -367,12 +367,29 @@ static unsigned int hpet_poll(struct file *file, poll_table * wait) return 0; } +#ifdef CONFIG_HPET_MMAP +#ifdef CONFIG_HPET_MMAP_DEFAULT +static int hpet_mmap_enabled = 1; +#else +static int hpet_mmap_enabled = 0; +#endif + +static __init int hpet_mmap_enable(char *str) +{ + get_option(&str, &hpet_mmap_enabled); + pr_info("HPET mmap %s\n", hpet_mmap_enabled ? "enabled" : "disabled"); + return 1; +} +__setup("hpet_mmap", hpet_mmap_enable); + static int hpet_mmap(struct file *file, struct vm_area_struct *vma) { -#ifdef CONFIG_HPET_MMAP struct hpet_dev *devp; unsigned long addr; + if (!hpet_mmap_enabled) + return -EACCES; + devp = file->private_data; addr = devp->hd_hpets->hp_hpet_phys; @@ -381,10 +398,13 @@ static int hpet_mmap(struct file *file, struct vm_area_struct *vma) vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot); return vm_iomap_memory(vma, addr, PAGE_SIZE); +} #else +static int hpet_mmap(struct file *file, struct vm_area_struct *vma) +{ return -ENOSYS; -#endif } +#endif static int hpet_fasync(int fd, struct file *file, int on) { |