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Commit 6e83557c authored by Michal Simek's avatar Michal Simek
Browse files

microblaze: Remove r0_ram pointer and PTO alignment 



r0_ram pool was used for saving/restoring register
content if hw exception happen. This poll was replaced by
pt_pool_space with PT_SIZE size.
Based on this change SAVE_STATE_ARG_SPACE was removed which
caused that PTO offset is zero that's why is also removed.

r0_ram space was used as scratchpad by v850. In early
Microblaze Linux developing phase was this part of code
blindly copied.

Signed-off-by: default avatarMichal Simek <monstr@monstr.eu>
parent d8748e73

arch/microblaze/include/asm/entry.h

+0 −36
Original line number Diff line number Diff line
@@ -31,40 +31,4 @@ DECLARE_PER_CPU(unsigned int, R11_SAVE); /* Temp variable for entry */ 
DECLARE_PER_CPU(unsigned int, CURRENT_SAVE); /* Saved current pointer */

# endif /* __ASSEMBLY__ */



#ifndef CONFIG_MMU



/* noMMU hasn't any space for args */

# define STATE_SAVE_ARG_SPACE	(0)



#else /* CONFIG_MMU */



/* If true, system calls save and restore all registers (except result

 * registers, of course).  If false, then `call clobbered' registers

 * will not be preserved, on the theory that system calls are basically

 * function calls anyway, and the caller should be able to deal with it.

 * This is a security risk, of course, as `internal' values may leak out

 * after a system call, but that certainly doesn't matter very much for

 * a processor with no MMU protection!  For a protected-mode kernel, it

 * would be faster to just zero those registers before returning.

 *

 * I can not rely on the glibc implementation. If you turn it off make

 * sure that r11/r12 is saved in user-space. --KAA

 *

 * These are special variables using by the kernel trap/interrupt code

 * to save registers in, at a time when there are no spare registers we

 * can use to do so, and we can't depend on the value of the stack

 * pointer.  This means that they must be within a signed 16-bit

 * displacement of 0x00000000.

 */



/* A `state save frame' is a struct pt_regs preceded by some extra space

 * suitable for a function call stack frame. */



/* Amount of room on the stack reserved for arguments and to satisfy the

 * C calling conventions, in addition to the space used by the struct

 * pt_regs that actually holds saved values. */

#define STATE_SAVE_ARG_SPACE	(6*4) /* Up to six arguments */



#endif /* CONFIG_MMU */



#endif /* _ASM_MICROBLAZE_ENTRY_H */

arch/microblaze/include/asm/processor.h

+1 −1
Original line number Diff line number Diff line
@@ -155,7 +155,7 @@ unsigned long get_wchan(struct task_struct *p); 
#  define task_regs(task) ((struct pt_regs *)task_tos(task) - 1)



#  define task_pt_regs_plus_args(tsk) \

	(((void *)task_pt_regs(tsk)) - STATE_SAVE_ARG_SPACE)

	((void *)task_pt_regs(tsk))



#  define task_sp(task)	(task_regs(task)->r1)

#  define task_pc(task)	(task_regs(task)->pc)

arch/microblaze/kernel/entry.S

+143 −149

File changed.

Preview size limit exceeded, changes collapsed.

arch/microblaze/kernel/hw_exception_handler.S

+10 −6
Original line number Diff line number Diff line
@@ -93,7 +93,7 @@ 
		lwi	r6, r1, PT_R6;		\

		lwi	r11, r1, PT_R11;	\

		lwi	r31, r1, PT_R31;	\

		lwi	r1, r0, TOPHYS(r0_ram + 0);

		lwi	r1, r1, PT_R1;

#endif /* CONFIG_MMU */



#define LWREG_NOP			\
@@ -208,8 +208,8 @@ 
 *      |      .      |

 *      |      .      |

 *

 * NO_MMU kernel use the same r0_ram pointed space - look to vmlinux.lds.S

 * which is used for storing register values - old style was, that value were

 * MMU kernel uses the same 'pt_pool_space' pointed space

 * which is used for storing register values - noMMu style was, that values were

 * stored in stack but in case of failure you lost information about register.

 * Currently you can see register value in memory in specific place.

 * In compare to with previous solution the speed should be the same.
@@ -228,8 +228,12 @@ 
 */



/* wrappers to restore state before coming to entry.S */



#ifdef CONFIG_MMU

.section .data

.align 4

pt_pool_space:

	.space	PT_SIZE



#ifdef DEBUG

/* Create space for exception counting. */

.section .data
@@ -299,10 +303,10 @@ _hw_exception_handler: 
#ifndef CONFIG_MMU

	addik	r1, r1, -(EX_HANDLER_STACK_SIZ); /* Create stack frame */

#else

	swi	r1, r0, TOPHYS(r0_ram + 0); /* GET_SP */

	swi	r1, r0, TOPHYS(pt_pool_space + PT_R1); /* GET_SP */

	/* Save date to kernel memory. Here is the problem

	 * when you came from user space */

	ori	r1, r0, TOPHYS(r0_ram + 28);

	ori	r1, r0, TOPHYS(pt_pool_space);

#endif

	swi	r3, r1, PT_R3

	swi	r4, r1, PT_R4

arch/microblaze/kernel/process.c

+1 −1
Original line number Diff line number Diff line
@@ -159,7 +159,7 @@ int copy_thread(unsigned long clone_flags, unsigned long usp, 
	}



	/* FIXME STATE_SAVE_PT_OFFSET; */

	ti->cpu_context.r1  = (unsigned long)childregs - STATE_SAVE_ARG_SPACE;

	ti->cpu_context.r1  = (unsigned long)childregs;

	/* we should consider the fact that childregs is a copy of the parent

	 * regs which were saved immediately after entering the kernel state

	 * before enabling VM. This MSR will be restored in switch_to and