diff options
| author | Vitaly Kuznetsov | 2015-08-01 16:08:08 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman | 2015-08-04 22:25:29 -0700 |
| commit | d7646eaa7678fe5adc42247b4bdfbe9d9db8c253 (patch) | |
| tree | 3f8aa489b8aa7cf247aaf5fc306877b8332ffbfb /drivers/hv/hv.c | |
| parent | 2517281d63a2b09d94aedfb522943617048f337e (diff) | |
Drivers: hv: don't do hypercalls when hypercall_page is NULL
At the very late stage of kexec a driver (which are not being unloaded) can
try to post a message or signal an event. This will crash the kernel as we
already did hv_cleanup() and the hypercall page is NULL.
Move all common (between 32 and 64 bit code) declarations to the beginning
of the do_hypercall() function. Unfortunately we have to write the
!hypercall_page check twice to not mix declarations and code.
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/hv/hv.c')
| -rw-r--r-- | drivers/hv/hv.c | 13 |
1 files changed, 8 insertions, 5 deletions
diff --git a/drivers/hv/hv.c b/drivers/hv/hv.c index 5b870424b502..41d8072d61d9 100644 --- a/drivers/hv/hv.c +++ b/drivers/hv/hv.c @@ -93,11 +93,14 @@ static int query_hypervisor_info(void) */ static u64 do_hypercall(u64 control, void *input, void *output) { -#ifdef CONFIG_X86_64 - u64 hv_status = 0; u64 input_address = (input) ? virt_to_phys(input) : 0; u64 output_address = (output) ? virt_to_phys(output) : 0; void *hypercall_page = hv_context.hypercall_page; +#ifdef CONFIG_X86_64 + u64 hv_status = 0; + + if (!hypercall_page) + return (u64)ULLONG_MAX; __asm__ __volatile__("mov %0, %%r8" : : "r" (output_address) : "r8"); __asm__ __volatile__("call *%3" : "=a" (hv_status) : @@ -112,13 +115,13 @@ static u64 do_hypercall(u64 control, void *input, void *output) u32 control_lo = control & 0xFFFFFFFF; u32 hv_status_hi = 1; u32 hv_status_lo = 1; - u64 input_address = (input) ? virt_to_phys(input) : 0; u32 input_address_hi = input_address >> 32; u32 input_address_lo = input_address & 0xFFFFFFFF; - u64 output_address = (output) ? virt_to_phys(output) : 0; u32 output_address_hi = output_address >> 32; u32 output_address_lo = output_address & 0xFFFFFFFF; - void *hypercall_page = hv_context.hypercall_page; + + if (!hypercall_page) + return (u64)ULLONG_MAX; __asm__ __volatile__ ("call *%8" : "=d"(hv_status_hi), "=a"(hv_status_lo) : "d" (control_hi), |