Messages in this thread | | | Date | Thu, 27 May 2010 10:24:30 +0200 | From | Michal Simek <> | Subject | Re: [PATCH 1/2 v2] FLAT: split the stack & data alignments |
| |
Mike Frysinger wrote: > 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 <vapier@gentoo.org>
Solve the problem on Microblaze:
Tested-by: Michal Simek <monstr@monstr.eu>
Who will add it to mainline?
Thanks, Michal
> --- > 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))
-- Michal Simek, Ing. (M.Eng) w: www.monstr.eu p: +42-0-721842854 Maintainer of Linux kernel 2.6 Microblaze Linux - http://www.monstr.eu/fdt/ Microblaze U-BOOT custodian
| |