From: Buland Singh <bsingh@xxxxxxxxxx>
[ 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@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
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 240b6cf1d97c..72e073895ed9 100644
--- a/drivers/char/hpet.c
+++ b/drivers/char/hpet.c
@@ -376,7 +376,7 @@ 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)
{
--
2.19.1
