Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754787AbbDMUSE (ORCPT ); Mon, 13 Apr 2015 16:18:04 -0400 Received: from vegas.theobroma-systems.com ([144.76.126.164]:46238 "EHLO mail.theobroma-systems.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754583AbbDMUR7 (ORCPT ); Mon, 13 Apr 2015 16:17:59 -0400 From: Philipp Tomsich To: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Cc: Philipp Tomsich , Andrew Pinski , Christoph Muellner , Benedikt Huber , Andreas Kraschitzer , Kumar Sankaran , Catalin Marinas Subject: [PATCH v4 22/24] arm64:ilp32: use compat for stack_t Date: Mon, 13 Apr 2015 21:44:32 +0200 Message-Id: <09081413bd99e0a04e9783dc44fcd52eaeab1af1.1428953303.git.philipp.tomsich@theobroma-systems.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: References: In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4630 Lines: 134 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 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 Signed-off-by: Christoph Muellner --- 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 #include #include +#include /* * 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 #undef __SYSCALL -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/