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>
diff --git a/arch/x86/include/asm/ptrace.h b/arch/x86/include/asm/ptrace.h
index 19f16eb..7e560b6 100644
--- a/arch/x86/include/asm/ptrace.h
+++ b/arch/x86/include/asm/ptrace.h
@@ -203,6 +203,13 @@
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