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Commit 9b064fc3 authored by Al Viro's avatar Al Viro
Browse files

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: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 5c49574f

arch/arm64/include/asm/compat.h

+3 −2
Original line number Diff line number Diff line
@@ -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 {

arch/x86/include/asm/ptrace.h

+7 −0
Original line number Diff line number Diff line
@@ -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

include/linux/compat.h

+3 −0
Original line number Diff line number Diff line
@@ -65,6 +65,9 @@ 


#endif /* CONFIG_HAVE_SYSCALL_WRAPPERS */



#ifndef compat_user_stack_pointer

#define compat_user_stack_pointer() current_user_stack_pointer()

#endif

#define compat_jiffies_to_clock_t(x)	\

		(((unsigned long)(x) * COMPAT_USER_HZ) / HZ)