On Sunday, December 27, 2015 11:04:12 PM Warner Losh wrote: > Author: imp > Date: Sun Dec 27 23:04:11 2015 > New Revision: 292809 > URL: https://svnweb.freebsd.org/changeset/base/292809 > > Log: > The FILE structure has a mbstate_t in it. This structure needs to be > aligned on a int64_t boundary. However, when we allocate the array of > these structures, we use ALIGNBYTES which defaults to sizeof(int) on > arm, i386 and others. The i386 stuff can handle unaligned accesses > seemlessly. However, arm cannot. Take this into account when creating > the array of FILEs, and add some comments about why. > > Differential Revision: https://reviews.freebsd.org/D4708 > > Modified: > head/lib/libc/stdio/findfp.c > > Modified: head/lib/libc/stdio/findfp.c > ============================================================================== > --- head/lib/libc/stdio/findfp.c Sun Dec 27 23:04:10 2015 > (r292808) > +++ head/lib/libc/stdio/findfp.c Sun Dec 27 23:04:11 2015 > (r292809) > @@ -41,6 +41,7 @@ __FBSDID("$FreeBSD$"); > #include <unistd.h> > #include <stdio.h> > #include <stdlib.h> > +#include <stdint.h> > #include <string.h> > > #include <spinlock.h> > @@ -96,11 +97,22 @@ moreglue(int n) > struct glue *g; > static FILE empty = { ._fl_mutex = PTHREAD_MUTEX_INITIALIZER }; > FILE *p; > + size_t align; > > - g = (struct glue *)malloc(sizeof(*g) + ALIGNBYTES + n * sizeof(FILE)); > + /* > + * FILE has a mbstate_t variable. This variable tries to be int64_t > + * aligned through its definition. int64_t may be larger than void *, > + * which is the size traditionally used for ALIGNBYTES. So, use our own > + * rounding instead of the MI ALIGN macros. If for some reason > + * ALIGNBYTES is larger than int64_t, respect that too. There appears to > + * be no portable way to ask for FILE's alignment requirements other > + * than just knowing here. > + */ > + align = MAX(ALIGNBYTES, sizeof(int64_t)); > + g = (struct glue *)malloc(sizeof(*g) + align + n * sizeof(FILE)); > if (g == NULL) > return (NULL); > - p = (FILE *)ALIGN(g + 1); > + p = (FILE *)roundup((uintptr_t)(g + 1), align);
Can this use posix_memalign() rather than doing the alignment by hand? -- John Baldwin _______________________________________________ svn-src-head@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-head To unsubscribe, send any mail to "svn-src-head-unsubscr...@freebsd.org"
