diff options
| -rw-r--r-- | arch/x86/include/asm/syscall.h | 14 | ||||
| -rw-r--r-- | arch/x86/kernel/ptrace.c | 21 | ||||
| -rw-r--r-- | include/asm-generic/syscall.h | 8 |
3 files changed, 21 insertions, 22 deletions
diff --git a/arch/x86/include/asm/syscall.h b/arch/x86/include/asm/syscall.h index d82f39bb790..8d33bc5462d 100644 --- a/arch/x86/include/asm/syscall.h +++ b/arch/x86/include/asm/syscall.h @@ -1,7 +1,7 @@ /* * Access to user system call parameters and results * - * Copyright (C) 2008 Red Hat, Inc. All rights reserved. + * Copyright (C) 2008-2009 Red Hat, Inc. All rights reserved. * * This copyrighted material is made available to anyone wishing to use, * modify, copy, or redistribute it subject to the terms and conditions @@ -16,13 +16,13 @@ #include <linux/sched.h> #include <linux/err.h> -static inline long syscall_get_nr(struct task_struct *task, - struct pt_regs *regs) +/* + * Only the low 32 bits of orig_ax are meaningful, so we return int. + * This importantly ignores the high bits on 64-bit, so comparisons + * sign-extend the low 32 bits. + */ +static inline int syscall_get_nr(struct task_struct *task, struct pt_regs *regs) { - /* - * We always sign-extend a -1 value being set here, - * so this is always either -1L or a syscall number. - */ return regs->orig_ax; } diff --git a/arch/x86/kernel/ptrace.c b/arch/x86/kernel/ptrace.c index 8d7d5c9c1be..7b058a2dc66 100644 --- a/arch/x86/kernel/ptrace.c +++ b/arch/x86/kernel/ptrace.c @@ -325,16 +325,6 @@ static int putreg(struct task_struct *child, return set_flags(child, value); #ifdef CONFIG_X86_64 - /* - * Orig_ax is really just a flag with small positive and - * negative values, so make sure to always sign-extend it - * from 32 bits so that it works correctly regardless of - * whether we come from a 32-bit environment or not. - */ - case offsetof(struct user_regs_struct, orig_ax): - value = (long) (s32) value; - break; - case offsetof(struct user_regs_struct,fs_base): if (value >= TASK_SIZE_OF(child)) return -EIO; @@ -1126,10 +1116,15 @@ static int putreg32(struct task_struct *child, unsigned regno, u32 value) case offsetof(struct user32, regs.orig_eax): /* - * Sign-extend the value so that orig_eax = -1 - * causes (long)orig_ax < 0 tests to fire correctly. + * A 32-bit debugger setting orig_eax means to restore + * the state of the task restarting a 32-bit syscall. + * Make sure we interpret the -ERESTART* codes correctly + * in case the task is not actually still sitting at the + * exit from a 32-bit syscall with TS_COMPAT still set. */ - regs->orig_ax = (long) (s32) value; + regs->orig_ax = value; + if (syscall_get_nr(child, regs) >= 0) + task_thread_info(child)->status |= TS_COMPAT; break; case offsetof(struct user32, regs.eflags): diff --git a/include/asm-generic/syscall.h b/include/asm-generic/syscall.h index ea8087b55ff..5c122ae6bfa 100644 --- a/include/asm-generic/syscall.h +++ b/include/asm-generic/syscall.h @@ -1,7 +1,7 @@ /* * Access to user system call parameters and results * - * Copyright (C) 2008 Red Hat, Inc. All rights reserved. + * Copyright (C) 2008-2009 Red Hat, Inc. All rights reserved. * * This copyrighted material is made available to anyone wishing to use, * modify, copy, or redistribute it subject to the terms and conditions @@ -32,9 +32,13 @@ struct pt_regs; * If @task is not executing a system call, i.e. it's blocked * inside the kernel for a fault or signal, returns -1. * + * Note this returns int even on 64-bit machines. Only 32 bits of + * system call number can be meaningful. If the actual arch value + * is 64 bits, this truncates to 32 bits so 0xffffffff means -1. + * * It's only valid to call this when @task is known to be blocked. */ -long syscall_get_nr(struct task_struct *task, struct pt_regs *regs); +int syscall_get_nr(struct task_struct *task, struct pt_regs *regs); /** * syscall_rollback - roll back registers after an aborted system call |