| Message ID | 20181024183519.27354-1-jcmvbkbc@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v2] linux-user/flatload: fix initial stack pointer alignment | expand |
On 24/10/2018 19:35, Max Filippov wrote: > Stack pointer alignment code incorrectly adds stack_size to sp instead > of subtracting it. It also does not take flat_argvp_envp_on_stack() into > account when calculating stack_size. This results in initial stack > pointer misalignment with certain set of command line arguments and > environment variables and correct alignment for the same binary with a > different set of arguments. This misalignment causes failures in the > following tests in the testsuite of gcc built for xtensa uclinux: > > gcc.dg/torture/vshuf-v64qi.c > gcc.dg/torture/vshuf-v8sf.c > gcc.dg/torture/vshuf-v8si.c > > Signed-off-by: Max Filippov <jcmvbkbc@gmail.com> > --- > Changes v1->v2: > - make sp adjustment unconditional > > linux-user/flatload.c | 6 +++--- > 1 file changed, 3 insertions(+), 3 deletions(-) > > diff --git a/linux-user/flatload.c b/linux-user/flatload.c > index 2eefe55e5000..0122ab3afe65 100644 > --- a/linux-user/flatload.c > +++ b/linux-user/flatload.c > @@ -771,10 +771,10 @@ int load_flt_binary(struct linux_binprm *bprm, struct image_info *info) > /* Enforce final stack alignment of 16 bytes. This is sufficient > for all current targets, and excess alignment is harmless. */ > stack_len = bprm->envc + bprm->argc + 2; > - stack_len += 3; /* argc, arvg, argp */ > + stack_len += flat_argvp_envp_on_stack() ? 2 : 0; /* arvg, argp */ > + stack_len += 1; /* argc */ > stack_len *= sizeof(abi_ulong); > - if ((sp + stack_len) & 15) > - sp -= 16 - ((sp + stack_len) & 15); > + sp -= (sp - stack_len) & 15; > sp = loader_build_argptr(bprm->envc, bprm->argc, sp, p, > flat_argvp_envp_on_stack()); > > Reviewed-by: Laurent Vivier <lvivier@redhat.com>
diff --git a/linux-user/flatload.c b/linux-user/flatload.c index 2eefe55e5000..0122ab3afe65 100644 --- a/linux-user/flatload.c +++ b/linux-user/flatload.c @@ -771,10 +771,10 @@ int load_flt_binary(struct linux_binprm *bprm, struct image_info *info) /* Enforce final stack alignment of 16 bytes. This is sufficient for all current targets, and excess alignment is harmless. */ stack_len = bprm->envc + bprm->argc + 2; - stack_len += 3; /* argc, arvg, argp */ + stack_len += flat_argvp_envp_on_stack() ? 2 : 0; /* arvg, argp */ + stack_len += 1; /* argc */ stack_len *= sizeof(abi_ulong); - if ((sp + stack_len) & 15) - sp -= 16 - ((sp + stack_len) & 15); + sp -= (sp - stack_len) & 15; sp = loader_build_argptr(bprm->envc, bprm->argc, sp, p, flat_argvp_envp_on_stack());
Stack pointer alignment code incorrectly adds stack_size to sp instead of subtracting it. It also does not take flat_argvp_envp_on_stack() into account when calculating stack_size. This results in initial stack pointer misalignment with certain set of command line arguments and environment variables and correct alignment for the same binary with a different set of arguments. This misalignment causes failures in the following tests in the testsuite of gcc built for xtensa uclinux: gcc.dg/torture/vshuf-v64qi.c gcc.dg/torture/vshuf-v8sf.c gcc.dg/torture/vshuf-v8si.c Signed-off-by: Max Filippov <jcmvbkbc@gmail.com> --- Changes v1->v2: - make sp adjustment unconditional linux-user/flatload.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)