Patch "rtc: msc313: Fix function prototype mismatch in msc313_rtc_probe()" has been added to the 6.1-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    rtc: msc313: Fix function prototype mismatch in msc313_rtc_probe()

to the 6.1-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     rtc-msc313-fix-function-prototype-mismatch-in-msc313.patch
and it can be found in the queue-6.1 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit d4cbc8a25e8b3992ada8694ede5a3c9db72ec8b2
Author: Kees Cook <keescook@xxxxxxxxxxxx>
Date:   Fri Dec 2 10:45:30 2022 -0800

    rtc: msc313: Fix function prototype mismatch in msc313_rtc_probe()
    
    [ Upstream commit 21b8a1dd56a163825e5749b303858fb902ebf198 ]
    
    With clang's kernel control flow integrity (kCFI, CONFIG_CFI_CLANG),
    indirect call targets are validated against the expected function
    pointer prototype to make sure the call target is valid to help mitigate
    ROP attacks. If they are not identical, there is a failure at run time,
    which manifests as either a kernel panic or thread getting killed.
    
    msc313_rtc_probe() was passing clk_disable_unprepare() directly, which
    did not have matching prototypes for devm_add_action_or_reset()'s
    callback argument. Refactor to use devm_clk_get_enabled() instead.
    
    This was found as a result of Clang's new -Wcast-function-type-strict
    flag, which is more sensitive than the simpler -Wcast-function-type,
    which only checks for type width mismatches.
    
    Reported-by: kernel test robot <lkp@xxxxxxxxx>
    Link: https://lore.kernel.org/lkml/202211041527.HD8TLSE1-lkp@xxxxxxxxx
    Suggested-by: Christophe JAILLET <christophe.jaillet@xxxxxxxxxx>
    Cc: Daniel Palmer <daniel@xxxxxxxxx>
    Cc: Romain Perier <romain.perier@xxxxxxxxx>
    Cc: Alessandro Zummo <a.zummo@xxxxxxxxxxxx>
    Cc: Alexandre Belloni <alexandre.belloni@xxxxxxxxxxx>
    Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
    Cc: linux-rtc@xxxxxxxxxxxxxxx
    Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
    Reviewed-by: Daniel Palmer <daniel@xxxxxxxxx>
    Tested-by: Daniel Palmer <daniel@xxxxxxxxx>
    Link: https://lore.kernel.org/r/20221202184525.gonna.423-kees@xxxxxxxxxx
    Signed-off-by: Alexandre Belloni <alexandre.belloni@xxxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/rtc/rtc-msc313.c b/drivers/rtc/rtc-msc313.c
index f3fde013c4b8..8d7737e0e2e0 100644
--- a/drivers/rtc/rtc-msc313.c
+++ b/drivers/rtc/rtc-msc313.c
@@ -212,22 +212,12 @@ static int msc313_rtc_probe(struct platform_device *pdev)
 		return ret;
 	}
 
-	clk = devm_clk_get(dev, NULL);
+	clk = devm_clk_get_enabled(dev, NULL);
 	if (IS_ERR(clk)) {
 		dev_err(dev, "No input reference clock\n");
 		return PTR_ERR(clk);
 	}
 
-	ret = clk_prepare_enable(clk);
-	if (ret) {
-		dev_err(dev, "Failed to enable the reference clock, %d\n", ret);
-		return ret;
-	}
-
-	ret = devm_add_action_or_reset(dev, (void (*) (void *))clk_disable_unprepare, clk);
-	if (ret)
-		return ret;
-
 	rate = clk_get_rate(clk);
 	writew(rate & 0xFFFF, priv->rtc_base + REG_RTC_FREQ_CW_L);
 	writew((rate >> 16) & 0xFFFF, priv->rtc_base + REG_RTC_FREQ_CW_H);