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Date:      Tue, 8 Nov 2011 00:02:52 GMT
From:      Alexander Best <arundel@FreeBSD.org>
To:        freebsd-gnats-submit@FreeBSD.org
Subject:   kern/162366: [ath] several shifts overflowing in sys/dev/ath code
Message-ID:  <201111080002.pA802quv069245@red.freebsd.org>
Resent-Message-ID: <201111080010.pA80A67L004633@freefall.freebsd.org>

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>Number:         162366
>Category:       kern
>Synopsis:       [ath] several shifts overflowing in sys/dev/ath code
>Confidential:   no
>Severity:       non-critical
>Priority:       medium
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Tue Nov 08 00:10:06 UTC 2011
>Closed-Date:
>Last-Modified:
>Originator:     Alexander Best
>Release:        10.0-CURRENT
>Organization:
>Environment:
FreeBSD otaku 10.0-CURRENT FreeBSD 10.0-CURRENT #6: Fri Nov  4 14:33:13 CET 2011     arundel@otaku:/usr/obj/usr/git-freebsd-head/sys/ARUNDEL  amd64
>Description:
clang warns about several shift overflows in sys/dev/ath code:

/usr/git-freebsd-head/sys/dev/ath/ath_hal/ar5210/ar5210_power.c:36:3: warning: signed shift result (0x200000000) requires 35 bits to represent, but 'int' only has 32 bits [-Wshift-overflow]
                OS_REG_RMW_FIELD(ah, AR_SCR, AR_SCR_SLE, AR_SCR_SLE_ALLOW);
                ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/git-freebsd-head/sys/dev/ath/ath_hal/ah_internal.h:471:42: note: expanded from macro 'OS_REG_RMW_FIELD'
                (OS_REG_READ(_a, _r) &~ (_f)) | (((_v) << _f##_S) & (_f)))
                                                       ^
/usr/git-freebsd-head/sys/dev/ath/ah_osdep.h:127:49: note: expanded from macro 'OS_REG_WRITE'
            (bus_space_handle_t)(_ah)->ah_sh, (_reg), (_val))
                                                       ^~~~
/usr/git-freebsd-head/sys/dev/ath/ath_hal/ar5210/ar5210_power.c:90:3: warning: signed shift result (0x100000000) requires 34 bits to represent, but 'int' only has 32 bits [-Wshift-overflow]
                OS_REG_RMW_FIELD(ah, AR_SCR, AR_SCR_SLE, AR_SCR_SLE_SLP);
                ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/git-freebsd-head/sys/dev/ath/ath_hal/ah_internal.h:471:42: note: expanded from macro 'OS_REG_RMW_FIELD'
                (OS_REG_READ(_a, _r) &~ (_f)) | (((_v) << _f##_S) & (_f)))
                                                       ^
/usr/git-freebsd-head/sys/dev/ath/ah_osdep.h:127:49: note: expanded from macro 'OS_REG_WRITE'
            (bus_space_handle_t)(_ah)->ah_sh, (_reg), (_val))
                                                       ^~~~
2 warnings generated.

/usr/git-freebsd-head/sys/dev/ath/ath_hal/ar5211/ar5211_power.c:79:3: warning: signed shift result (0x100000000) requires 34 bits to represent, but 'int' only has 32 bits [-Wshift-overflow]
                OS_REG_RMW_FIELD(ah, AR_SCR, AR_SCR_SLE, AR_SCR_SLE_SLP);
                ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/git-freebsd-head/sys/dev/ath/ath_hal/ah_internal.h:471:42: note: expanded from macro 'OS_REG_RMW_FIELD'
                (OS_REG_READ(_a, _r) &~ (_f)) | (((_v) << _f##_S) & (_f)))
                                                       ^
/usr/git-freebsd-head/sys/dev/ath/ah_osdep.h:127:49: note: expanded from macro 'OS_REG_WRITE'
            (bus_space_handle_t)(_ah)->ah_sh, (_reg), (_val))
                                                       ^~~~
/usr/git-freebsd-head/sys/dev/ath/ath_hal/ar5211/ar5211_power.c:92:3: warning: signed shift result (0x200000000) requires 35 bits to represent, but 'int' only has 32 bits [-Wshift-overflow]
                OS_REG_RMW_FIELD(ah, AR_SCR, AR_SCR_SLE, AR_SCR_SLE_NORM);
                ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/git-freebsd-head/sys/dev/ath/ath_hal/ah_internal.h:471:42: note: expanded from macro 'OS_REG_RMW_FIELD'
                (OS_REG_READ(_a, _r) &~ (_f)) | (((_v) << _f##_S) & (_f)))
                                                       ^
/usr/git-freebsd-head/sys/dev/ath/ah_osdep.h:127:49: note: expanded from macro 'OS_REG_WRITE'
            (bus_space_handle_t)(_ah)->ah_sh, (_reg), (_val))
                                                       ^~~~
2 warnings generated.

dimitry andric explained in [1] that at least the first case appears to be a real bug and not a bogus compiler warning. the other cases need to be investigated in detail, too.

[1] http://lists.freebsd.org/pipermail/freebsd-toolchain/2011-November/000282.html
>How-To-Repeat:

>Fix:


>Release-Note:
>Audit-Trail:
>Unformatted:



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