Variables declared in a switch statement before any case statements
cannot be automatically initialized with compiler instrumentation (as
they are not part of any execution flow). With GCC's proposed automatic
stack variable initialization feature, this triggers a warning (and they
don't get initialized). Clang's automatic stack variable initialization
(via CONFIG_INIT_STACK_ALL=y) doesn't throw a warning, but it also
doesn't initialize such variables[1]. Note that these warnings (or silent
skipping) happen before the dead-store elimination optimization phase,
so even when the automatic initializations are later elided in favor of
direct initializations, the warnings remain.
To avoid these problems, move such variables into the "case" where
they're used or lift them up into the main function body.
drivers/gpu/drm/i915/display/intel_display.c: In function ‘check_digital_port_conflicts’:
drivers/gpu/drm/i915/display/intel_display.c:12963:17: warning: statement will never be executed [-Wswitch-unreachable]
12963 | unsigned int port_mask;
| ^~~~~~~~~
drivers/gpu/drm/i915/intel_pm.c: In function ‘vlv_get_fifo_size’:
drivers/gpu/drm/i915/intel_pm.c:474:7: warning: statement will never be executed [-Wswitch-unreachable]
474 | u32 dsparb, dsparb2, dsparb3;
| ^~~~~~
drivers/gpu/drm/i915/intel_pm.c: In function ‘vlv_atomic_update_fifo’:
drivers/gpu/drm/i915/intel_pm.c:1997:7: warning: statement will never be executed [-Wswitch-unreachable]
1997 | u32 dsparb, dsparb2, dsparb3;
| ^~~~~~
[1] https://bugs.llvm.org/show_bug.cgi?id=44916
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/202002201602.92CADF7D@keescook
WARN_ON(!connector_state->crtc);
switch (encoder->type) {
- unsigned int port_mask;
case INTEL_OUTPUT_DDI:
if (WARN_ON(!HAS_DDI(to_i915(dev))))
break;
case INTEL_OUTPUT_DP:
case INTEL_OUTPUT_HDMI:
case INTEL_OUTPUT_EDP:
- port_mask = 1 << encoder->port;
-
/* the same port mustn't appear more than once */
- if (used_ports & port_mask)
+ if (used_ports & BIT(encoder->port))
ret = false;
- used_ports |= port_mask;
+ used_ports |= BIT(encoder->port);
break;
case INTEL_OUTPUT_DP_MST:
used_mst_ports |=
struct vlv_fifo_state *fifo_state = &crtc_state->wm.vlv.fifo_state;
enum pipe pipe = crtc->pipe;
int sprite0_start, sprite1_start;
+ u32 dsparb, dsparb2, dsparb3;
switch (pipe) {
- u32 dsparb, dsparb2, dsparb3;
case PIPE_A:
dsparb = I915_READ(DSPARB);
dsparb2 = I915_READ(DSPARB2);
const struct vlv_fifo_state *fifo_state =
&crtc_state->wm.vlv.fifo_state;
int sprite0_start, sprite1_start, fifo_size;
+ u32 dsparb, dsparb2, dsparb3;
if (!crtc_state->fifo_changed)
return;
spin_lock(&uncore->lock);
switch (crtc->pipe) {
- u32 dsparb, dsparb2, dsparb3;
case PIPE_A:
dsparb = intel_uncore_read_fw(uncore, DSPARB);
dsparb2 = intel_uncore_read_fw(uncore, DSPARB2);