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sh: add kexec jump support

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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: Magnus Damm <damm@igel.co.jp>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
This commit is contained in:
Magnus Damm 2009-03-18 08:51:29 +00:00 committed by Paul Mundt
parent e4e063d0c2
commit b7cf6ddc13
3 changed files with 202 additions and 32 deletions
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7
arch/sh/Kconfig
View File

@ -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

32
arch/sh/kernel/machine_kexec.c
View File

@ -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,
unsigned long reboot_code_buffer,
unsigned long start_address) ATTRIB_NORET;
typedef void (*relocate_new_kernel_t)(unsigned long indirection_page,
unsigned long reboot_code_buffer,
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)

195
arch/sh/kernel/relocate_kernel.S
View File

@ -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.
*/
@ -17,14 +19,135 @@ 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 */
/* stack setting */
add r8,r5
mov r5,r15
/* 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
/* 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 */
mov r4,r0 /* cmd = indirection_page */
0:
mov.l @r4+,r0 /* cmd = *ind++ */
@ -37,52 +160,70 @@ relocate_new_kernel:
tst #1,r0
bt 2f
bra 0b
mov r2,r5
mov r2,r5
2: /* else if(cmd & IND_INDIRECTION) ind = addr */
tst #2,r0
bt 3f
bra 0b
mov r2,r4
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
nop
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
nop
.align 2
10:
.long PAGE_SIZE
11:
.long 0
12:
.long 0x20000000 ! RB=1
relocate_new_kernel_end: