This responds to the feedback from Ingo that we should be using explicitly-sized types and fixes a typo in the patch description. -- From: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx> Stephen Rothwell reported: http://lkml.kernel.org/r/20160226164406.065a1ffc@xxxxxxxxxxxxxxxx that the Memory Protection Keys patches from the tip tree broke a build-time check on an ARM build because they changed the ABI of siginfo. A u64 was used for the protection key field in siginfo. When the containing union was aligned, this u64 unioned nicely with the two 'void *'s in _addr_bnd. But, on 32-bit, if the union was unaligned, the u64 might grow the size of the union, breaking the ABI for subsequent fields. To fix this, we replace the u64 with an '__u32'. The __u32 is guaranteed to union well with the pointers from _addr_bnd. It is also plenty large enough to store the 16-bit pkey we have today on x86. I also shouldn't have been using a u64 in a userspace API to begin with. Fixes: cd0ea35ff551 ("signals, pkeys: Notify userspace about protection key faults") Signed-off-by: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx> Acked-by: Stehen Rothwell <sfr@xxxxxxxxxxxxxxxx> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Cc: Ingo Molnar <mingo@xxxxxxx> Cc: "H. Peter Anvin" <hpa@xxxxxxxxx> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx> Cc: linux-next@xxxxxxxxxxxxxxx Cc: linux-kernel@xxxxxxxxxxxxxxx Cc: Helge Deller <deller@xxxxxx> --- b/arch/ia64/include/uapi/asm/siginfo.h | 2 +- b/arch/mips/include/uapi/asm/siginfo.h | 2 +- b/include/uapi/asm-generic/siginfo.h | 2 +- 3 files changed, 3 insertions(+), 3 deletions(-) diff -puN include/uapi/asm-generic/siginfo.h~pkeys-101-fix-siginfo include/uapi/asm-generic/siginfo.h --- a/include/uapi/asm-generic/siginfo.h~pkeys-101-fix-siginfo 2016-02-29 09:22:45.327228965 -0800 +++ b/include/uapi/asm-generic/siginfo.h 2016-02-29 09:22:45.333229241 -0800 @@ -98,7 +98,7 @@ typedef struct siginfo { void __user *_upper; } _addr_bnd; /* used when si_code=SEGV_PKUERR */ - u64 _pkey; + __u32 _pkey; }; } _sigfault; diff -puN arch/mips/include/uapi/asm/siginfo.h~pkeys-101-fix-siginfo arch/mips/include/uapi/asm/siginfo.h --- a/arch/mips/include/uapi/asm/siginfo.h~pkeys-101-fix-siginfo 2016-02-29 09:22:45.330229103 -0800 +++ b/arch/mips/include/uapi/asm/siginfo.h 2016-02-29 09:22:45.333229241 -0800 @@ -93,7 +93,7 @@ typedef struct siginfo { void __user *_upper; } _addr_bnd; /* used when si_code=SEGV_PKUERR */ - u64 _pkey; + __u32 _pkey; }; } _sigfault; diff -puN arch/ia64/include/uapi/asm/siginfo.h~pkeys-101-fix-siginfo arch/ia64/include/uapi/asm/siginfo.h --- a/arch/ia64/include/uapi/asm/siginfo.h~pkeys-101-fix-siginfo 2016-02-29 09:22:45.331229149 -0800 +++ b/arch/ia64/include/uapi/asm/siginfo.h 2016-02-29 09:22:45.333229241 -0800 @@ -70,7 +70,7 @@ typedef struct siginfo { void __user *_upper; } _addr_bnd; /* used when si_code=SEGV_PKUERR */ - u64 _pkey; + __u32 _pkey; }; } _sigfault; _ -- To unsubscribe from this list: send the line "unsubscribe linux-next" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
