[ Upstream commit 24d48a61f2666630da130cc2ec2e526eacf229e3 ]
Commit '3d035f580699 ("drivers/char/hpet.c: allow user controlled mmap for user processes")' introduced a new kernel command line parameter hpet_mmap, that is required to expose the memory map of the HPET registers to user-space. Unfortunately the kernel command line parameter 'hpet_mmap' is broken and never takes effect due to missing '=' character in the __setup() code of hpet_mmap_enable.
Before this patch:
dmesg output with the kernel command line parameter hpet_mmap=1
[ 0.204152] HPET mmap disabled
dmesg output with the kernel command line parameter hpet_mmap=0
[ 0.204192] HPET mmap disabled
After this patch:
dmesg output with the kernel command line parameter hpet_mmap=1
[ 0.203945] HPET mmap enabled
dmesg output with the kernel command line parameter hpet_mmap=0
[ 0.204652] HPET mmap disabled
Fixes: 3d035f580699 ("drivers/char/hpet.c: allow user controlled mmap for user processes") Signed-off-by: Buland Singh bsingh@redhat.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/char/hpet.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/char/hpet.c b/drivers/char/hpet.c index d5d4cd82b9f7..978a782f5e30 100644 --- a/drivers/char/hpet.c +++ b/drivers/char/hpet.c @@ -377,7 +377,7 @@ static __init int hpet_mmap_enable(char *str) pr_info("HPET mmap %s\n", hpet_mmap_enabled ? "enabled" : "disabled"); return 1; } -__setup("hpet_mmap", hpet_mmap_enable); +__setup("hpet_mmap=", hpet_mmap_enable);
static int hpet_mmap(struct file *file, struct vm_area_struct *vma) {