mmc: dw_mmc: remove UBSAN warning in dw_mci_setup_bus()

This patch removes following UBSAN warnings in dw_mci_setup_bus().

  UBSAN: Undefined behaviour in drivers/mmc/host/dw_mmc.c:1102:14
  shift exponent 250 is too large for 32-bit type 'unsigned int'
  Call trace:
  [<ffffff90080908a8>] dump_backtrace+0x0/0x380
  [<ffffff9008090c3c>] show_stack+0x14/0x20
  [<ffffff90087457b8>] dump_stack+0xe0/0x120
  [<ffffff90087b1360>] ubsan_epilogue+0x18/0x68
  [<ffffff90087b1a94>] __ubsan_handle_shift_out_of_bounds+0x18c/0x1bc
  [<ffffff9008d89cb8>] dw_mci_setup_bus+0x3a0/0x438
  [...]

  UBSAN: Undefined behaviour in drivers/mmc/host/dw_mmc.c:1132:27
  shift exponent 250 is too large for 32-bit type 'unsigned int'
  Call trace:
  [<ffffff90080908a8>] dump_backtrace+0x0/0x380
  [<ffffff9008090c3c>] show_stack+0x14/0x20
  [<ffffff90087457b8>] dump_stack+0xe0/0x120
  [<ffffff90087b1360>] ubsan_epilogue+0x18/0x68
  [<ffffff90087b1a94>] __ubsan_handle_shift_out_of_bounds+0x18c/0x1bc
  [<ffffff9008d89c9c>] dw_mci_setup_bus+0x384/0x438
  [...]

The warnings are caused because of bit shift which is used to
filter spamming message for CONFIG_MMC_CLKGATE, but the config is
already removed. So this patch just removes the shift.

[Backport for current version.]

Change-Id: I1760db1b0e42ddd490aa7539e6c1474a047387c4
Signed-off-by: Seung-Woo Kim <sw0312.kim@samsung.com>

diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
index b354c8b..0de4db1 100644 (file)
--- a/drivers/mmc/host/dw_mmc.c
+++ b/drivers/mmc/host/dw_mmc.c
@@ -979,12 +979,11 @@ static void dw_mci_setup_bus(struct dw_mci_slot *slot, bool force_clkinit)
 
                div = (host->bus_hz != clock) ? DIV_ROUND_UP(div, 2) : 0;
 
-               if ((clock << div) != slot->__clk_old || force_clkinit)
-                       dev_info(&slot->mmc->class_dev,
-                                "Bus speed (slot %d) = %dHz (slot req %dHz, actual %dHZ div = %d)\n",
-                                slot->id, host->bus_hz, clock,
-                                div ? ((host->bus_hz / div) >> 1) :
-                                host->bus_hz, div);
+               dev_info(&slot->mmc->class_dev,
+                        "Bus speed (slot %d) = %dHz (slot req %dHz, actual %dHZ div = %d)\n",
+                        slot->id, host->bus_hz, clock,
+                        div ? ((host->bus_hz / div) >> 1) :
+                        host->bus_hz, div);
 
                /* disable clock */
                mci_writel(host, CLKENA, 0);
@@ -1007,9 +1006,6 @@ static void dw_mci_setup_bus(struct dw_mci_slot *slot, bool force_clkinit)
 
                /* inform CIU */
                mci_send_cmd(slot, sdmmc_cmd_bits, 0);
-
-               /* keep the clock with reflecting clock dividor */
-               slot->__clk_old = clock << div;
        }
 
        host->current_speed = clock;

diff --git a/drivers/mmc/host/dw_mmc.h b/drivers/mmc/host/dw_mmc.h
index f45ab91..c6e034f 100644 (file)
--- a/drivers/mmc/host/dw_mmc.h
+++ b/drivers/mmc/host/dw_mmc.h
@@ -234,9 +234,6 @@ extern int dw_mci_resume(struct dw_mci *host);
  * @queue_node: List node for placing this node in the @queue list of
  *     &struct dw_mci.
  * @clock: Clock rate configured by set_ios(). Protected by host->lock.
- * @__clk_old: The last updated clock with reflecting clock divider.
- *     Keeping track of this helps us to avoid spamming the console
- *     with CONFIG_MMC_CLKGATE.
  * @flags: Random state bits associated with the slot.
  * @id: Number of this slot.
  * @sdio_id: Number of this slot in the SDIO interrupt registers.
@@ -253,7 +250,6 @@ struct dw_mci_slot {
        struct list_head        queue_node;
 
        unsigned int            clock;
-       unsigned int            __clk_old;
 
        unsigned long           flags;
 #define DW_MMC_CARD_PRESENT    0