Commit 1eef5d2f authored by Russell King's avatar Russell King
Browse files

ARM: domains: switch to keeping domain value in register 



Rather than modifying both the domain access control register and our
per-thread copy, modify only the domain access control register, and
use the per-thread copy to save and restore the register over context
switches.  We can also avoid the explicit initialisation of the
init thread_info structure.

This allows us to avoid needing to gain access to the thread information
at the uaccess control sites.

Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
parent d770e558

arch/arm/include/asm/domain.h

+15 −5
Original line number Original line Diff line number Diff line
@@ -59,6 +59,17 @@ 




#ifndef __ASSEMBLY__

#ifndef __ASSEMBLY__





static inline unsigned int get_domain(void)

{

	unsigned int domain;



	asm(

	"mrc	p15, 0, %0, c3, c0	@ get domain"

	 : "=r" (domain));



	return domain;

}



#ifdef CONFIG_CPU_USE_DOMAINS

#ifdef CONFIG_CPU_USE_DOMAINS

static inline void set_domain(unsigned val)

static inline void set_domain(unsigned val)

{

{
@@ -70,11 +81,10 @@ static inline void set_domain(unsigned val) 




#define modify_domain(dom,type)					\

#define modify_domain(dom,type)					\

	do {							\

	do {							\

	struct thread_info *thread = current_thread_info();	\

		unsigned int domain = get_domain();		\

	unsigned int domain = thread->cpu_domain;		\

		domain &= ~domain_val(dom, DOMAIN_MANAGER);	\

		domain &= ~domain_val(dom, DOMAIN_MANAGER);	\

	thread->cpu_domain = domain | domain_val(dom, type);	\

		domain = domain | domain_val(dom, type);	\

	set_domain(thread->cpu_domain);				\

		set_domain(domain);				\

	} while (0)

	} while (0)





#else

#else

arch/arm/include/asm/thread_info.h

+0 −3
Original line number Original line Diff line number Diff line
@@ -74,9 +74,6 @@ struct thread_info { 
	.flags		= 0,						\

	.flags		= 0,						\

	.preempt_count	= INIT_PREEMPT_COUNT,				\

	.preempt_count	= INIT_PREEMPT_COUNT,				\

	.addr_limit	= KERNEL_DS,					\

	.addr_limit	= KERNEL_DS,					\

	.cpu_domain	= domain_val(DOMAIN_USER, DOMAIN_MANAGER) |	\

			  domain_val(DOMAIN_KERNEL, DOMAIN_MANAGER) |	\

			  domain_val(DOMAIN_IO, DOMAIN_CLIENT),		\

}

}





#define init_thread_info	(init_thread_union.thread_info)

#define init_thread_info	(init_thread_union.thread_info)

arch/arm/kernel/entry-armv.S

+2 −0
Original line number Original line Diff line number Diff line
@@ -770,6 +770,8 @@ ENTRY(__switch_to) 
	ldr	r4, [r2, #TI_TP_VALUE]

	ldr	r4, [r2, #TI_TP_VALUE]

	ldr	r5, [r2, #TI_TP_VALUE + 4]

	ldr	r5, [r2, #TI_TP_VALUE + 4]

#ifdef CONFIG_CPU_USE_DOMAINS

#ifdef CONFIG_CPU_USE_DOMAINS

	mrc	p15, 0, r6, c3, c0, 0		@ Get domain register

	str	r6, [r1, #TI_CPU_DOMAIN]	@ Save old domain register

	ldr	r6, [r2, #TI_CPU_DOMAIN]

	ldr	r6, [r2, #TI_CPU_DOMAIN]

#endif

#endif

	switch_tls r1, r4, r5, r3, r7

	switch_tls r1, r4, r5, r3, r7

arch/arm/kernel/process.c

+10 −3
Original line number Original line Diff line number Diff line
@@ -146,10 +146,9 @@ void __show_regs(struct pt_regs *regs) 
		buf[0] = '\0';

		buf[0] = '\0';

#ifdef CONFIG_CPU_CP15_MMU

#ifdef CONFIG_CPU_CP15_MMU

		{

		{

			unsigned int transbase, dac;

			unsigned int transbase, dac = get_domain();

			asm("mrc p15, 0, %0, c2, c0\n\t"

			asm("mrc p15, 0, %0, c2, c0\n\t"

			    "mrc p15, 0, %1, c3, c0\n"

			    : "=r" (transbase));

			    : "=r" (transbase), "=r" (dac));

			snprintf(buf, sizeof(buf), "  Table: %08x  DAC: %08x",

			snprintf(buf, sizeof(buf), "  Table: %08x  DAC: %08x",

			  	transbase, dac);

			  	transbase, dac);

		}

		}
@@ -210,6 +209,14 @@ copy_thread(unsigned long clone_flags, unsigned long stack_start, 




	memset(&thread->cpu_context, 0, sizeof(struct cpu_context_save));

	memset(&thread->cpu_context, 0, sizeof(struct cpu_context_save));





	/*

	 * Copy the initial value of the domain access control register

	 * from the current thread: thread->addr_limit will have been

	 * copied from the current thread via setup_thread_stack() in

	 * kernel/fork.c

	 */

	thread->cpu_domain = get_domain();



	if (likely(!(p->flags & PF_KTHREAD))) {

	if (likely(!(p->flags & PF_KTHREAD))) {

		*childregs = *current_pt_regs();

		*childregs = *current_pt_regs();

		childregs->ARM_r0 = 0;

		childregs->ARM_r0 = 0;

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