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Commit b7cf6ddc authored by Magnus Damm's avatar Magnus Damm Committed by Paul Mundt
Browse files

sh: add kexec jump support 



Add kexec jump support to the SuperH architecture.

Similar to the x86 implementation, with the following
exceptions:

- Instead of separating the assembly code flow into
two parts for regular kexec and kexec jump we use a
single code path. In the assembly snippet regular
kexec is just kexec jump that never comes back.

- Instead of using a swap page when moving data between
pages the page copy assembly routine has been modified
to exchange the data between the pages using registers.

- We walk the page list twice in machine_kexec() to
do and undo physical to virtual address conversion.

Signed-off-by: default avatarMagnus Damm <damm@igel.co.jp>
Signed-off-by: default avatarPaul Mundt <lethal@linux-sh.org>
parent e4e063d0

arch/sh/Kconfig

+7 −0
Original line number Diff line number Diff line
@@ -559,6 +559,13 @@ config CRASH_DUMP 


	  For more details see Documentation/kdump/kdump.txt



config KEXEC_JUMP

	bool "kexec jump (EXPERIMENTAL)"

	depends on SUPERH32 && KEXEC && HIBERNATION && EXPERIMENTAL

	help

	  Jump between original kernel and kexeced kernel and invoke

	  code via KEXEC



config SECCOMP

	bool "Enable seccomp to safely compute untrusted bytecode"

	depends on PROC_FS

arch/sh/kernel/machine_kexec.c

+27 −5
Original line number Diff line number Diff line
@@ -14,20 +14,21 @@ 
#include <linux/delay.h>

#include <linux/reboot.h>

#include <linux/numa.h>

#include <linux/suspend.h>

#include <asm/pgtable.h>

#include <asm/pgalloc.h>

#include <asm/mmu_context.h>

#include <asm/io.h>

#include <asm/cacheflush.h>



typedef NORET_TYPE void (*relocate_new_kernel_t)(

				unsigned long indirection_page,

typedef void (*relocate_new_kernel_t)(unsigned long indirection_page,

				      unsigned long reboot_code_buffer,

				unsigned long start_address) ATTRIB_NORET;

				      unsigned long start_address);



extern const unsigned char relocate_new_kernel[];

extern const unsigned int relocate_new_kernel_size;

extern void *gdb_vbr_vector;

extern void *vbr_base;



void machine_shutdown(void)

{
@@ -72,7 +73,6 @@ static void kexec_info(struct kimage *image) 
 */

void machine_kexec(struct kimage *image)

{



	unsigned long page_list;

	unsigned long reboot_code_buffer;

	relocate_new_kernel_t rnk;
@@ -92,6 +92,11 @@ void machine_kexec(struct kimage *image) 
			*ptr = (unsigned long) phys_to_virt(*ptr);

	}



#ifdef CONFIG_KEXEC_JUMP

	if (image->preserve_context)

		save_processor_state();

#endif



	/* Interrupts aren't acceptable while we reboot */

	local_irq_disable();
@@ -117,6 +122,23 @@ void machine_kexec(struct kimage *image) 
	/* now call it */

	rnk = (relocate_new_kernel_t) reboot_code_buffer;

	(*rnk)(page_list, reboot_code_buffer, image->start);



#ifdef CONFIG_KEXEC_JUMP

	asm volatile("ldc %0, vbr" : : "r" (&vbr_base) : "memory");

	local_irq_disable();

	clear_bl_bit();

	if (image->preserve_context)

		restore_processor_state();



	/* Convert page list back to physical addresses, what a mess. */

	for (ptr = &image->head; (entry = *ptr) && !(entry & IND_DONE);

	     ptr = (*ptr & IND_INDIRECTION) ?

	       phys_to_virt(*ptr & PAGE_MASK) : ptr + 1) {

		if (*ptr & IND_SOURCE || *ptr & IND_INDIRECTION ||

		    *ptr & IND_DESTINATION)

			*ptr = virt_to_phys(*ptr);

	}

#endif

}



void arch_crash_save_vmcoreinfo(void)

arch/sh/kernel/relocate_kernel.S

+168 −27
Original line number Diff line number Diff line
@@ -4,6 +4,8 @@ 
 *

 * LANDISK/sh4 is supported. Maybe, SH archtecture works well.

 *

 * 2009-03-18 Magnus Damm - Added Kexec Jump support

 *

 * This source code is licensed under the GNU General Public License,

 * Version 2.  See the file COPYING for more details.

 */
@@ -17,12 +19,133 @@ relocate_new_kernel: 
	/* r5 = reboot_code_buffer */

	/* r6 = start_address      */



	mov.l	10f,r8	  /* PAGE_SIZE */

	mov.l	10f, r0		/* PAGE_SIZE */

	add	r5, r0		/* setup new stack at end of control page */



	/* save r15->r8 to new stack */

	mov.l	r15, @-r0

	mov	r0, r15

	mov.l	r14, @-r15

	mov.l	r13, @-r15

	mov.l	r12, @-r15

	mov.l	r11, @-r15

	mov.l	r10, @-r15

	mov.l	r9, @-r15

	mov.l	r8, @-r15



	/* save other random registers */

	sts.l	macl, @-r15

	sts.l	mach, @-r15

	stc.l	gbr, @-r15

	stc.l	ssr, @-r15

	stc.l	sr, @-r15

	sts.l	pr, @-r15

	stc.l	spc, @-r15



	/* switch to bank1 and save r7->r0 */

	mov.l	12f, r9

	stc	sr, r8

	or	r9, r8

	ldc	r8, sr

	mov.l	r7, @-r15

	mov.l	r6, @-r15

	mov.l	r5, @-r15

	mov.l	r4, @-r15

	mov.l	r3, @-r15

	mov.l	r2, @-r15

	mov.l	r1, @-r15

	mov.l	r0, @-r15



	/* switch to bank0 and save r7->r0 */

	mov.l	12f, r9

	not	r9, r9

	stc	sr, r8

	and	r9, r8

	ldc	r8, sr

	mov.l	r7, @-r15

	mov.l	r6, @-r15

	mov.l	r5, @-r15

	mov.l	r4, @-r15

	mov.l	r3, @-r15

	mov.l	r2, @-r15

	mov.l	r1, @-r15

	mov.l	r0, @-r15



	mov.l	r4, @-r15	/* save indirection page again */



	bsr	swap_pages	/* swap pages before jumping to new kernel */

	 nop



	mova	11f, r0

	mov.l	r15, @r0	/* save pointer to stack */



	jsr	@r6		/* hand over control to new kernel */

	 nop



	mov.l	11f, r15	/* get pointer to stack */

	mov.l	@r15+, r4	/* restore r4 to get indirection page */



	bsr	swap_pages	/* swap pages back to previous state */

	 nop



	/* make sure bank0 is active and restore r0->r7 */

	mov.l	12f, r9

	not	r9, r9

	stc	sr, r8

	and	r9, r8

	ldc	r8, sr

	mov.l	@r15+, r0

	mov.l	@r15+, r1

	mov.l	@r15+, r2

	mov.l	@r15+, r3

	mov.l	@r15+, r4

	mov.l	@r15+, r5

	mov.l	@r15+, r6

	mov.l	@r15+, r7



	/* switch to bank1 and restore r0->r7 */

	mov.l	12f, r9

	stc	sr, r8

	or	r9, r8

	ldc	r8, sr

	mov.l	@r15+, r0

	mov.l	@r15+, r1

	mov.l	@r15+, r2

	mov.l	@r15+, r3

	mov.l	@r15+, r4

	mov.l	@r15+, r5

	mov.l	@r15+, r6

	mov.l	@r15+, r7



	/* switch back to bank0 */

	mov.l	12f, r9

	not	r9, r9

	stc	sr, r8

	and	r9, r8

	ldc	r8, sr



	/*  stack setting */

	add	r8,r5

	mov	r5,r15

	/* restore other random registers */

	ldc.l	@r15+, spc

	lds.l	@r15+, pr

	ldc.l	@r15+, sr

	ldc.l	@r15+, ssr

	ldc.l	@r15+, gbr

	lds.l	@r15+, mach

	lds.l	@r15+, macl



	/* restore r8->r15 */

	mov.l	@r15+, r8

	mov.l	@r15+, r9

	mov.l	@r15+, r10

	mov.l	@r15+, r11

	mov.l	@r15+, r12

	mov.l	@r15+, r13

	mov.l	@r15+, r14

	mov.l	@r15+, r15

	rts

	 nop



swap_pages:

	bra	1f

	 mov	r4,r0	  /* cmd = indirection_page */

0:
@@ -45,44 +168,62 @@ relocate_new_kernel: 
	bra	0b

	 mov	r2,r4



3:	/* else if(cmd & IND_DONE) goto 6  */

3:	/* else if(cmd & IND_DONE) return */

	tst	#4,r0

	bt	4f

	bra	6f

	rts

	 nop



4:	/* else if(cmd & IND_SOURCE) memcpy(dst,addr,PAGE_SIZE) */

	tst	#8,r0

	bt	0b



	mov	r8,r3

	mov.l	10f,r3	  /* PAGE_SIZE */

	shlr2	r3

	shlr2	r3

5:

	dt	r3

	mov.l	@r2+,r1   /*  16n+0 */

	mov.l	r1,@r5

	add	#4,r5

	mov.l	@r2+,r1	  /*  16n+4 */

	mov.l	r1,@r5

	add	#4,r5

	mov.l	@r2+,r1   /*  16n+8 */

	mov.l	r1,@r5

	add	#4,r5

	mov.l	@r2+,r1   /*  16n+12 */

	mov.l	r1,@r5

	add	#4,r5



	/* regular kexec just overwrites the destination page

	 * with the contents of the source page.

	 * for the kexec jump case we need to swap the contents

	 * of the pages.

	 * to keep it simple swap the contents for both cases.

	 */

	mov.l	@(0, r2), r8

	mov.l	@(0, r5), r1

	mov.l	r8, @(0, r5)

	mov.l	r1, @(0, r2)



	mov.l	@(4, r2), r8

	mov.l	@(4, r5), r1

	mov.l	r8, @(4, r5)

	mov.l	r1, @(4, r2)



	mov.l	@(8, r2), r8

	mov.l	@(8, r5), r1

	mov.l	r8, @(8, r5)

	mov.l	r1, @(8, r2)



	mov.l	@(12, r2), r8

	mov.l	@(12, r5), r1

	mov.l	r8, @(12, r5)

	mov.l	r1, @(12, r2)



	add	#16,r5

	add	#16,r2

	bf	5b



	bra	0b

	 nop

6:

	jmp @r6

	nop



	.align 2

10:

	.long	PAGE_SIZE

11:

	.long	0

12:

	.long	0x20000000 ! RB=1



relocate_new_kernel_end: