Commit a6f05a6a authored by H. Peter Anvin's avatar H. Peter Anvin
Browse files

x86-64: make compat_start_thread() match start_thread() 



For no real good reason, compat_start_thread() was embedded inline in
<asm/elf.h> whereas the native start_thread() lives in process_*.c.
Move compat_start_thread() to process_64.c, remove gratuitious
differences, and fix a few items which mostly look like bit rot.

In particular, compat_start_thread() didn't do free_thread_xstate(),
which means it was hanging on to the xstate store area even when it
was not needed.  It was also not setting old_rsp, but it looks like
that generally shouldn't matter for a 32-bit process.

Note: compat_start_thread *has* to be a macro, since it is tested with
start_thread_ia32() as the out of line function name.

Signed-off-by: default avatarH. Peter Anvin <hpa@zytor.com>
Acked-by: default avatarSuresh Siddha <suresh.b.siddha@intel.com>
parent 36a07902

arch/x86/include/asm/elf.h

+2 −18
Original line number Diff line number Diff line
@@ -157,19 +157,6 @@ do { \ 


#define compat_elf_check_arch(x)	elf_check_arch_ia32(x)



static inline void start_ia32_thread(struct pt_regs *regs, u32 ip, u32 sp)

{

	loadsegment(fs, 0);

	loadsegment(ds, __USER32_DS);

	loadsegment(es, __USER32_DS);

	load_gs_index(0);

	regs->ip = ip;

	regs->sp = sp;

	regs->flags = X86_EFLAGS_IF;

	regs->cs = __USER32_CS;

	regs->ss = __USER32_DS;

}



static inline void elf_common_init(struct thread_struct *t,

				   struct pt_regs *regs, const u16 ds)

{
@@ -191,11 +178,8 @@ do { \ 
#define	COMPAT_ELF_PLAT_INIT(regs, load_addr)		\

	elf_common_init(&current->thread, regs, __USER_DS)



#define	compat_start_thread(regs, ip, sp)		\

do {							\

	start_ia32_thread(regs, ip, sp);		\

	set_fs(USER_DS);				\

} while (0)

void start_thread_ia32(struct pt_regs *regs, u32 new_ip, u32 new_sp);

#define compat_start_thread start_thread_ia32



#define COMPAT_SET_PERSONALITY(ex)			\

do {							\

arch/x86/kernel/process_64.c

+22 −1
Original line number Diff line number Diff line
@@ -356,7 +356,7 @@ start_thread(struct pt_regs *regs, unsigned long new_ip, unsigned long new_sp) 
	percpu_write(old_rsp, new_sp);

	regs->cs		= __USER_CS;

	regs->ss		= __USER_DS;

	regs->flags		= 0x200;

	regs->flags		= X86_EFLAGS_IF;

	set_fs(USER_DS);

	/*

	 * Free the old FP and other extended state
@@ -365,6 +365,27 @@ start_thread(struct pt_regs *regs, unsigned long new_ip, unsigned long new_sp) 
}

EXPORT_SYMBOL_GPL(start_thread);



#ifdef CONFIG_IA32_EMULATION

void start_thread_ia32(struct pt_regs *regs, u32 new_ip, u32 new_sp)

{

	loadsegment(fs, 0);

	loadsegment(ds, __USER32_DS);

	loadsegment(es, __USER32_DS);

	load_gs_index(0);

	regs->ip		= new_ip;

	regs->sp		= new_sp;

	percpu_write(old_rsp, new_sp);

	regs->cs		= __USER32_CS;

	regs->ss		= __USER32_DS;

	regs->flags		= X86_EFLAGS_IF;

	set_fs(USER_DS);

	/*

	 * Free the old FP and other extended state

	 */

	free_thread_xstate(current);

}

#endif



/*

 *	switch_to(x,y) should switch tasks from x to y.

 *

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