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authorAl Viro <viro@zeniv.linux.org.uk>2012-12-14 13:49:35 -0500
committerAl Viro <viro@zeniv.linux.org.uk>2012-12-19 18:07:40 -0500
commit9b064fc3f95a8e44e929fdf4d6037334ea03d15b (patch)
treedd1a2a6075667841f88b1ea8b62f4df2e18c3c68 /arch
parentnew helper: restore_altstack() (diff)
downloadlinux-dev-9b064fc3f95a8e44e929fdf4d6037334ea03d15b.tar.xz
linux-dev-9b064fc3f95a8e44e929fdf4d6037334ea03d15b.zip
new helper: compat_user_stack_pointer()
Compat counterpart of current_user_stack_pointer(); for most of the biarch architectures those two are identical, but e.g. arm64 and arm use different registers for stack pointer... Note that amd64 variants of current_user_stack_pointer/compat_user_stack_pointer do *not* rely on pt_regs having been through FIXUP_TOP_OF_STACK. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to '')
-rw-r--r--arch/arm64/include/asm/compat.h5
-rw-r--r--arch/x86/include/asm/ptrace.h7
2 files changed, 10 insertions, 2 deletions
diff --git a/arch/arm64/include/asm/compat.h b/arch/arm64/include/asm/compat.h
index 37e610dc084e..d9ec40217a27 100644
--- a/arch/arm64/include/asm/compat.h
+++ b/arch/arm64/include/asm/compat.h
@@ -209,10 +209,11 @@ static inline compat_uptr_t ptr_to_compat(void __user *uptr)
return (u32)(unsigned long)uptr;
}
+#define compat_user_stack_pointer() (current_pt_regs()->compat_sp)
+
static inline void __user *arch_compat_alloc_user_space(long len)
{
- struct pt_regs *regs = task_pt_regs(current);
- return (void __user *)regs->compat_sp - len;
+ return (void __user *)compat_user_stack_pointer() - len;
}
struct compat_ipc64_perm {
diff --git a/arch/x86/include/asm/ptrace.h b/arch/x86/include/asm/ptrace.h
index 19f16ebaf4fa..7e560b6daf5d 100644
--- a/arch/x86/include/asm/ptrace.h
+++ b/arch/x86/include/asm/ptrace.h
@@ -203,6 +203,13 @@ static inline bool user_64bit_mode(struct pt_regs *regs)
return regs->cs == __USER_CS || regs->cs == pv_info.extra_user_64bit_cs;
#endif
}
+
+#define current_user_stack_pointer() this_cpu_read(old_rsp)
+/* ia32 vs. x32 difference */
+#define compat_user_stack_pointer() \
+ (test_thread_flag(TIF_IA32) \
+ ? current_pt_regs()->sp \
+ : this_cpu_read(old_rsp))
#endif
#ifdef CONFIG_X86_32