Commit 5c0d72b1 authored by Michal Simek's avatar Michal Simek
Browse files

microblaze: Remove PER_CPU(KM) variable 



There is a way howto remove Kernel Mode variable. It is easier
to parse UMS bit in MSR to find out if I come from kernel or user
space. Loading MSR content should be in one cycle and loading
PER_CPU variable depends on memory state.

Signed-off-by: default avatarMichal Simek <monstr@monstr.eu>
parent 3fbd93e5

arch/microblaze/kernel/entry.S

+20 −23
Original line number Diff line number Diff line
@@ -275,9 +275,12 @@ C_ENTRY(_user_exception): 
	addi	r14, r14, 4	/* return address is 4 byte after call */

	swi	r11, r0, TOPHYS(r0_ram + PTO + PT_R11);	/* Save r11 */



	lwi	r11, r0, TOPHYS(PER_CPU(KM));/* See if already in kernel mode.*/

	beqi	r11, 1f;		/* Jump ahead if coming from user */

/* Kernel-mode state save. */

	mfs	r11, rmsr

	nop

	andi	r11, r11, MSR_UMS

	bnei	r11, 1f



/* Kernel-mode state save - kernel execve */

	lwi	r11, r0, TOPHYS(PER_CPU(ENTRY_SP)); /* Reload kernel stack-ptr*/

	tophys(r1,r11);

	swi	r11, r1, (PT_R1-PT_SIZE); /* Save original SP. */
@@ -307,8 +310,6 @@ C_ENTRY(_user_exception): 
	swi	r0, r1, PTO+PT_MODE;			/* Was in user-mode. */

	lwi	r11, r0, TOPHYS(PER_CPU(ENTRY_SP));

	swi	r11, r1, PTO+PT_R1;		/* Store user SP.  */

	addi	r11, r0, 1;

	swi	r11, r0, TOPHYS(PER_CPU(KM));	/* Now we're in kernel-mode.  */

2:	lwi	CURRENT_TASK, r0, TOPHYS(PER_CPU(CURRENT_SAVE));

	/* Save away the syscall number.  */

	swi	r12, r1, PTO+PT_R0;
@@ -423,7 +424,6 @@ C_ENTRY(ret_from_trap): 


/* Finally, return to user state.  */

1:

	swi	r0, r0, PER_CPU(KM);	/* Now officially in user state. */

	swi	CURRENT_TASK, r0, PER_CPU(CURRENT_SAVE); /* save current */

	VM_OFF;

	tophys(r1,r1);
@@ -511,8 +511,10 @@ C_ENTRY(sys_rt_sigreturn_wrapper): 
	enable_irq;							\

	set_ee;								\

	/* See if already in kernel mode.*/				\

	lwi	r11, r0, TOPHYS(PER_CPU(KM));				\

	beqi	r11, 1f;		/* Jump ahead if coming from user */\

	mfs	r11, rmsr;						\

	nop;								\

	andi	r11, r11, MSR_UMS;					\

	bnei	r11, 1f;						\

	/* Kernel-mode state save.  */					\

	/* Reload kernel stack-ptr. */					\

	lwi	r11, r0, TOPHYS(PER_CPU(ENTRY_SP));			\
@@ -544,8 +546,6 @@ C_ENTRY(sys_rt_sigreturn_wrapper): 
	swi	r0, r1, PTO+PT_MODE; /* Was in user-mode.  */		\

	lwi	r11, r0, TOPHYS(PER_CPU(ENTRY_SP));			\

	swi	r11, r1, PTO+PT_R1; /* Store user SP.  */		\

	addi	r11, r0, 1;						\

	swi	r11, r0, TOPHYS(PER_CPU(KM)); /* Now we're in kernel-mode.*/\

2:	lwi	CURRENT_TASK, r0, TOPHYS(PER_CPU(CURRENT_SAVE));	\

	/* Save away the syscall number.  */				\

	swi	r0, r1, PTO+PT_R0;					\
@@ -686,7 +686,7 @@ C_ENTRY(ret_from_exc): 
	add	r6, r0, r0;		/* Arg 2: sigset_t *oldset */



/* Finally, return to user state.  */

1:	swi	r0, r0, PER_CPU(KM);	/* Now officially in user state. */

1:

	swi	CURRENT_TASK, r0, PER_CPU(CURRENT_SAVE); /* save current */

	VM_OFF;

	tophys(r1,r1);
@@ -724,8 +724,10 @@ C_ENTRY(_interrupt): 
	swi	r1, r0, TOPHYS(PER_CPU(ENTRY_SP))

	swi	r11, r0, TOPHYS(PER_CPU(R11_SAVE));

	/* MS: See if already in kernel mode. */

	lwi	r11, r0, TOPHYS(PER_CPU(KM));

	beqi	r11, 1f; /* MS: Jump ahead if coming from user */

	mfs	r11, rmsr

	nop

	andi	r11, r11, MSR_UMS

	bnei	r11, 1f



/* Kernel-mode state save. */

	or	r11, r1, r0
@@ -761,10 +763,6 @@ C_ENTRY(_interrupt): 
	swi	r0, r1, PTO + PT_MODE;

	lwi	r11, r0, TOPHYS(PER_CPU(ENTRY_SP));

	swi	r11, r1, PTO+PT_R1;

	/* setup kernel mode to KM */

	addi	r11, r0, 1;

	swi	r11, r0, TOPHYS(PER_CPU(KM));



2:

	lwi	CURRENT_TASK, r0, TOPHYS(PER_CPU(CURRENT_SAVE));

	swi	r0, r1, PTO + PT_R0;
@@ -803,7 +801,6 @@ ret_from_irq: 
no_intr_resched:

    /* Disable interrupts, we are now committed to the state restore */

	disable_irq

	swi	r0, r0, PER_CPU(KM); /* MS: Now officially in user state. */

	swi	CURRENT_TASK, r0, PER_CPU(CURRENT_SAVE);

	VM_OFF;

	tophys(r1,r1);
@@ -858,8 +855,10 @@ C_ENTRY(_debug_exception): 
	set_bip;	/*equalize initial state for all possible entries*/

	clear_eip;

	enable_irq;

	lwi	r11, r0, TOPHYS(PER_CPU(KM));/* See if already in kernel mode.*/

	beqi	r11, 1f;		/* Jump ahead if coming from user */

	mfs	r11, rmsr

	nop

	andi	r11, r11, MSR_UMS

	bnei	r11, 1f

	/* Kernel-mode state save.  */

	lwi	r11, r0, TOPHYS(PER_CPU(ENTRY_SP)); /* Reload kernel stack-ptr*/

	tophys(r1,r11);
@@ -887,8 +886,6 @@ C_ENTRY(_debug_exception): 
	swi	r0, r1, PTO+PT_MODE; /* Was in user-mode.  */

	lwi	r11, r0, TOPHYS(PER_CPU(ENTRY_SP));

	swi	r11, r1, PTO+PT_R1; /* Store user SP.  */

	addi	r11, r0, 1;

	swi	r11, r0, TOPHYS(PER_CPU(KM));	/* Now we're in kernel-mode.  */

2:	lwi	CURRENT_TASK, r0, TOPHYS(PER_CPU(CURRENT_SAVE));

	/* Save away the syscall number.  */

	swi	r0, r1, PTO+PT_R0;
@@ -944,7 +941,7 @@ dbtrap_call: rtbd r11, 0; 




/* Finally, return to user state.  */

1:	swi	r0, r0, PER_CPU(KM);	/* Now officially in user state. */

1:

	swi	CURRENT_TASK, r0, PER_CPU(CURRENT_SAVE); /* save current */

	VM_OFF;

	tophys(r1,r1);

CRA Git | Maintained and supported by SUSTech CRA and CCSE