drm/radeon: fix possible segfault when parsing pm tables

commit f8e6bfc2ce162855fa4f9822a45659f4b542c960 upstream.

If we have a empty power table, bail early and allocate
the default power state.

Should fix:
https://bugs.freedesktop.org/show_bug.cgi?id=63865

Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/drivers/gpu/drm/radeon/radeon_atombios.c b/drivers/gpu/drm/radeon/radeon_atombios.c
index 38585c5..93044cb 100644 (file)
--- a/drivers/gpu/drm/radeon/radeon_atombios.c
+++ b/drivers/gpu/drm/radeon/radeon_atombios.c
@@ -1989,6 +1989,8 @@ static int radeon_atombios_parse_power_table_1_3(struct radeon_device *rdev)
        num_modes = power_info->info.ucNumOfPowerModeEntries;
        if (num_modes > ATOM_MAX_NUMBEROF_POWER_BLOCK)
                num_modes = ATOM_MAX_NUMBEROF_POWER_BLOCK;
+       if (num_modes == 0)
+               return state_index;
        rdev->pm.power_state = kzalloc(sizeof(struct radeon_power_state) * num_modes, GFP_KERNEL);
        if (!rdev->pm.power_state)
                return state_index;
@@ -2361,6 +2363,8 @@ static int radeon_atombios_parse_power_table_4_5(struct radeon_device *rdev)
        power_info = (union power_info *)(mode_info->atom_context->bios + data_offset);
 
        radeon_atombios_add_pplib_thermal_controller(rdev, &power_info->pplib.sThermalController);
+       if (power_info->pplib.ucNumStates == 0)
+               return state_index;
        rdev->pm.power_state = kzalloc(sizeof(struct radeon_power_state) *
                                       power_info->pplib.ucNumStates, GFP_KERNEL);
        if (!rdev->pm.power_state)
@@ -2459,6 +2463,8 @@ static int radeon_atombios_parse_power_table_6(struct radeon_device *rdev)
        non_clock_info_array = (struct NonClockInfoArray *)
                (mode_info->atom_context->bios + data_offset +
                 le16_to_cpu(power_info->pplib.usNonClockInfoArrayOffset));
+       if (state_array->ucNumEntries == 0)
+               return state_index;
        rdev->pm.power_state = kzalloc(sizeof(struct radeon_power_state) *
                                       state_array->ucNumEntries, GFP_KERNEL);
        if (!rdev->pm.power_state)
@@ -2549,7 +2555,9 @@ void radeon_atombios_get_power_modes(struct radeon_device *rdev)
                default:
                        break;
                }
-       } else {
+       }
+
+       if (state_index == 0) {
                rdev->pm.power_state = kzalloc(sizeof(struct radeon_power_state), GFP_KERNEL);
                if (rdev->pm.power_state) {
                        rdev->pm.power_state[0].clock_info =