Jivin Mike Frysinger lays it down ... > The stack and data have different alignment requirements, so don't force > them to wear the same shoe. Increase the data alignment to match that > which the elf2flt linker script has always been using: 0x20 bytes. Not > only does this bring the kernel loader in line with the toolchain, but > it also fixes a swath of gcc tests which try to force larger alignment > values but randomly fail when the FLAT loader fails to deliver. > > Signed-off-by: Mike Frysinger <vap...@gentoo.org>
Acked-by: David McCullough <david_mccullo...@mcafee.com> Cheers, Davidm > --- > v2 > - split changes & document better > > fs/binfmt_flat.c | 23 +++++++++++++++-------- > 1 files changed, 15 insertions(+), 8 deletions(-) > > diff --git a/fs/binfmt_flat.c b/fs/binfmt_flat.c > index 49566c1..b865622 100644 > --- a/fs/binfmt_flat.c > +++ b/fs/binfmt_flat.c > @@ -56,15 +56,22 @@ > #endif > > /* > - * User data (stack, data section and bss) needs to be aligned > - * for the same reasons as SLAB memory is, and to the same amount. > - * Avoid duplicating architecture specific code by using the same > - * macro as with SLAB allocation: > + * User data (data section and bss) needs to be aligned. > + * We pick 0x20 here because it is the max value elf2flt has always > + * used in producing FLAT files, and because it seems to be large > + * enough to make all the gcc alignment related tests happy. > + */ > +#define FLAT_DATA_ALIGN (0x20) > + > +/* > + * User data (stack) also needs to be aligned. > + * Here we can be a bit looser than the data sections since this > + * needs to only meet arch ABI requirements. > */ > #ifdef ARCH_SLAB_MINALIGN > -#define FLAT_DATA_ALIGN (ARCH_SLAB_MINALIGN) > +#define FLAT_STACK_ALIGN (ARCH_SLAB_MINALIGN) > #else > -#define FLAT_DATA_ALIGN (sizeof(void *)) > +#define FLAT_STACK_ALIGN (sizeof(void *)) > #endif > > #define RELOC_FAILED 0xff00ff01 /* Relocation incorrect > somewhere */ > @@ -129,7 +136,7 @@ static unsigned long create_flat_tables( > > sp = (unsigned long *)p; > sp -= (envc + argc + 2) + 1 + (flat_argvp_envp_on_stack() ? 2 : 0); > - sp = (unsigned long *) ((unsigned long)sp & -FLAT_DATA_ALIGN); > + sp = (unsigned long *) ((unsigned long)sp & -FLAT_STACK_ALIGN); > argv = sp + 1 + (flat_argvp_envp_on_stack() ? 2 : 0); > envp = argv + (argc + 1); > > @@ -876,7 +883,7 @@ static int load_flat_binary(struct linux_binprm * bprm, > struct pt_regs * regs) > stack_len = TOP_OF_ARGS - bprm->p; /* the strings */ > stack_len += (bprm->argc + 1) * sizeof(char *); /* the argv array */ > stack_len += (bprm->envc + 1) * sizeof(char *); /* the envp array */ > - stack_len += FLAT_DATA_ALIGN - 1; /* reserve for upcoming alignment */ > + stack_len += FLAT_STACK_ALIGN - 1; /* reserve for upcoming alignment */ > > res = load_flat_file(bprm, &libinfo, 0, &stack_len); > if (IS_ERR_VALUE(res)) > -- > 1.7.1 > > > -- David McCullough, david_mccullo...@mcafee.com, Ph:+61 734352815 McAfee - SnapGear http://www.mcafee.com http://www.uCdot.org _______________________________________________ uClinux-dev mailing list uClinux-dev@uclinux.org http://mailman.uclinux.org/mailman/listinfo/uclinux-dev This message was resent by uclinux-dev@uclinux.org To unsubscribe see: http://mailman.uclinux.org/mailman/options/uclinux-dev
