| Message ID | 09081413bd99e0a04e9783dc44fcd52eaeab1af1.1428953303.git.philipp.tomsich@theobroma-systems.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
> On Apr 13, 2015, at 1:18 PM, Philipp Tomsich <philipp.tomsich@theobroma-systems.com> wrote: > > We use a 'natively sized' stack_t in glibc (i.e. having a 32bit pointer for > ss_sp), which requires the invocation of the compat layer for the following > functionality: > * sigaltstack > * saving and restoring uc_stack during signal setup and returns Can you explain why you want to use a natively sized stack_t? My patches for glibc included changing stack_t too. I would rather keep the same size stack_t between lp64 and ilp32 due easier gdb support. Thanks, Andrew > > As the userspace stack_t is natively sized, we avoid code duplication in the > syscall table and can use the compat-functions to zero-extend the pointers > involved. > > Signed-off-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com> > Signed-off-by: Christoph Muellner <christoph.muellner@theobroma-systems.com> > --- > arch/arm64/kernel/signal.c | 19 +++++++++++++++++++ > arch/arm64/kernel/sys_ilp32.c | 44 +------------------------------------------ > 2 files changed, 20 insertions(+), 43 deletions(-) > > diff --git a/arch/arm64/kernel/signal.c b/arch/arm64/kernel/signal.c > index 99e36be..b3f6e52 100644 > --- a/arch/arm64/kernel/signal.c > +++ b/arch/arm64/kernel/signal.c > @@ -34,6 +34,7 @@ > #include <asm/fpsimd.h> > #include <asm/signal32.h> > #include <asm/vdso.h> > +#include <asm/syscalls.h> > > /* > * Do a signal return; undo the signal stack. These are aligned to 128-bit. > @@ -148,9 +149,22 @@ asmlinkage long sys_rt_sigreturn(struct pt_regs *regs) > if (restore_sigframe(regs, frame)) > goto badframe; > > + > +#if defined(CONFIG_ARM64_ILP32) > + if (is_ilp32_compat_task()) { > + /* For ILP32, we have a different stack_t (the ss_sp > + field will be only 32bit sized), which fits into > + the memory area reserved for the (larger) LP64 > + stack_t and which we place into uc_stack: this > + implies padding after the ILP32 stack_t. */ > + if (compat_restore_altstack((compat_stack_t*)&frame->uc.uc_stack)) > + goto badframe; > + } else > +#endif > if (restore_altstack(&frame->uc.uc_stack)) > goto badframe; > > + > return regs->regs[0]; > > badframe: > @@ -264,6 +278,11 @@ static int setup_rt_frame(int usig, struct ksignal *ksig, sigset_t *set, > __put_user_error(0, &frame->uc.uc_flags, err); > __put_user_error(NULL, &frame->uc.uc_link, err); > > +#if defined(CONFIG_ARM64_ILP32) > + if (is_ilp32_compat_task()) > + err |= __compat_save_altstack((compat_stack_t*)&frame->uc.uc_stack, regs->sp); > + else > +#endif > err |= __save_altstack(&frame->uc.uc_stack, regs->sp); > err |= setup_sigframe(frame, regs, set); > if (err == 0) { > diff --git a/arch/arm64/kernel/sys_ilp32.c b/arch/arm64/kernel/sys_ilp32.c > index 3471f27..31f82ca 100644 > --- a/arch/arm64/kernel/sys_ilp32.c > +++ b/arch/arm64/kernel/sys_ilp32.c > @@ -77,6 +77,7 @@ > > /* Pointer in struct */ > #define sys_mount compat_sys_mount > +#define sys_sigaltstack compat_sys_sigaltstack > > /* NUMA */ > /* unsigned long bitmaps */ > @@ -122,49 +123,6 @@ asmlinkage long ilp32_sys_mq_notify(mqd_t mqdes, const struct sigevent __user *u > but need special handling due to padding for SIGEV_THREAD. */ > #define sys_mq_notify ilp32_sys_mq_notify > > - > -/* sigaltstack needs some special handling as the > - padding for stack_t might not be non-zero. */ > -long ilp32_sys_sigaltstack(const stack_t __user *uss_ptr, > - stack_t __user *uoss_ptr) > -{ > - stack_t uss, uoss; > - int ret; > - mm_segment_t seg; > - > - if (uss_ptr) { > - if (!access_ok(VERIFY_READ, uss_ptr, sizeof(*uss_ptr))) > - return -EFAULT; > - if (__get_user(uss.ss_sp, &uss_ptr->ss_sp) | > - __get_user(uss.ss_flags, &uss_ptr->ss_flags) | > - __get_user(uss.ss_size, &uss_ptr->ss_size)) > - return -EFAULT; > - /* Zero extend the sp address and the size. */ > - uss.ss_sp = (void *)(uintptr_t)(unsigned int)(uintptr_t)uss.ss_sp; > - uss.ss_size = (size_t)(unsigned int)uss.ss_size; > - } > - seg = get_fs(); > - set_fs(KERNEL_DS); > - /* Note we need to use uoss as we have changed the segment to the > - kernel one so passing an user one around is wrong. */ > - ret = sys_sigaltstack((stack_t __force __user *) (uss_ptr ? &uss : NULL), > - (stack_t __force __user *) &uoss); > - set_fs(seg); > - if (ret >= 0 && uoss_ptr) { > - if (!access_ok(VERIFY_WRITE, uoss_ptr, sizeof(stack_t)) || > - __put_user(uoss.ss_sp, &uoss_ptr->ss_sp) || > - __put_user(uoss.ss_flags, &uoss_ptr->ss_flags) || > - __put_user(uoss.ss_size, &uoss_ptr->ss_size)) > - ret = -EFAULT; > - } > - return ret; > -} > - > -/* sigaltstack needs some special handling as the padding > - for stack_t might not be non-zero. */ > -#define sys_sigaltstack ilp32_sys_sigaltstack > - > - > #include <asm/syscalls.h> > > #undef __SYSCALL > -- > 1.9.1 >
diff --git a/arch/arm64/kernel/signal.c b/arch/arm64/kernel/signal.c index 99e36be..b3f6e52 100644 --- a/arch/arm64/kernel/signal.c +++ b/arch/arm64/kernel/signal.c @@ -34,6 +34,7 @@ #include <asm/fpsimd.h> #include <asm/signal32.h> #include <asm/vdso.h> +#include <asm/syscalls.h> /* * Do a signal return; undo the signal stack. These are aligned to 128-bit. @@ -148,9 +149,22 @@ asmlinkage long sys_rt_sigreturn(struct pt_regs *regs) if (restore_sigframe(regs, frame)) goto badframe; + +#if defined(CONFIG_ARM64_ILP32) + if (is_ilp32_compat_task()) { + /* For ILP32, we have a different stack_t (the ss_sp + field will be only 32bit sized), which fits into + the memory area reserved for the (larger) LP64 + stack_t and which we place into uc_stack: this + implies padding after the ILP32 stack_t. */ + if (compat_restore_altstack((compat_stack_t*)&frame->uc.uc_stack)) + goto badframe; + } else +#endif if (restore_altstack(&frame->uc.uc_stack)) goto badframe; + return regs->regs[0]; badframe: @@ -264,6 +278,11 @@ static int setup_rt_frame(int usig, struct ksignal *ksig, sigset_t *set, __put_user_error(0, &frame->uc.uc_flags, err); __put_user_error(NULL, &frame->uc.uc_link, err); +#if defined(CONFIG_ARM64_ILP32) + if (is_ilp32_compat_task()) + err |= __compat_save_altstack((compat_stack_t*)&frame->uc.uc_stack, regs->sp); + else +#endif err |= __save_altstack(&frame->uc.uc_stack, regs->sp); err |= setup_sigframe(frame, regs, set); if (err == 0) { diff --git a/arch/arm64/kernel/sys_ilp32.c b/arch/arm64/kernel/sys_ilp32.c index 3471f27..31f82ca 100644 --- a/arch/arm64/kernel/sys_ilp32.c +++ b/arch/arm64/kernel/sys_ilp32.c @@ -77,6 +77,7 @@ /* Pointer in struct */ #define sys_mount compat_sys_mount +#define sys_sigaltstack compat_sys_sigaltstack /* NUMA */ /* unsigned long bitmaps */ @@ -122,49 +123,6 @@ asmlinkage long ilp32_sys_mq_notify(mqd_t mqdes, const struct sigevent __user *u but need special handling due to padding for SIGEV_THREAD. */ #define sys_mq_notify ilp32_sys_mq_notify - -/* sigaltstack needs some special handling as the - padding for stack_t might not be non-zero. */ -long ilp32_sys_sigaltstack(const stack_t __user *uss_ptr, - stack_t __user *uoss_ptr) -{ - stack_t uss, uoss; - int ret; - mm_segment_t seg; - - if (uss_ptr) { - if (!access_ok(VERIFY_READ, uss_ptr, sizeof(*uss_ptr))) - return -EFAULT; - if (__get_user(uss.ss_sp, &uss_ptr->ss_sp) | - __get_user(uss.ss_flags, &uss_ptr->ss_flags) | - __get_user(uss.ss_size, &uss_ptr->ss_size)) - return -EFAULT; - /* Zero extend the sp address and the size. */ - uss.ss_sp = (void *)(uintptr_t)(unsigned int)(uintptr_t)uss.ss_sp; - uss.ss_size = (size_t)(unsigned int)uss.ss_size; - } - seg = get_fs(); - set_fs(KERNEL_DS); - /* Note we need to use uoss as we have changed the segment to the - kernel one so passing an user one around is wrong. */ - ret = sys_sigaltstack((stack_t __force __user *) (uss_ptr ? &uss : NULL), - (stack_t __force __user *) &uoss); - set_fs(seg); - if (ret >= 0 && uoss_ptr) { - if (!access_ok(VERIFY_WRITE, uoss_ptr, sizeof(stack_t)) || - __put_user(uoss.ss_sp, &uoss_ptr->ss_sp) || - __put_user(uoss.ss_flags, &uoss_ptr->ss_flags) || - __put_user(uoss.ss_size, &uoss_ptr->ss_size)) - ret = -EFAULT; - } - return ret; -} - -/* sigaltstack needs some special handling as the padding - for stack_t might not be non-zero. */ -#define sys_sigaltstack ilp32_sys_sigaltstack - - #include <asm/syscalls.h> #undef __SYSCALL