From: Seung-Woo Kim <sw0312.kim@samsung.com>
Date: Fri, 17 Jun 2016 04:19:09 +0000 (+0900)
Subject: mmc: dw_mmc: remove UBSAN warning in dw_mci_setup_bus()
X-Git-Tag: accepted/tizen/common/20161219.151653~390
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=538026a9703e2d6512feea8a679346bc1d343045;p=platform%2Fkernel%2Flinux-exynos.git

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
--- 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
--- 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