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authorMagnus Damm <damm@igel.co.jp>2009-03-18 08:51:29 +0000
committerPaul Mundt <lethal@linux-sh.org>2009-03-18 18:57:43 +0900
commitb7cf6ddc13186f9272438a97aa75972d496d0b0a (patch)
treef0b7e65b92a573dd10fc97b9bad0d832ed45f64b /arch/sh
parente4e063d0c288bd65c56dd855337780a541ed928d (diff)
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: Magnus Damm <damm@igel.co.jp> Signed-off-by: Paul Mundt <lethal@linux-sh.org>
Diffstat (limited to 'arch/sh')
-rw-r--r--arch/sh/Kconfig7
-rw-r--r--arch/sh/kernel/machine_kexec.c32
-rw-r--r--arch/sh/kernel/relocate_kernel.S195
3 files changed, 202 insertions, 32 deletions
diff --git a/arch/sh/Kconfig b/arch/sh/Kconfig
index 6c56495fd15..8d50d527c59 100644
--- a/arch/sh/Kconfig
+++ b/arch/sh/Kconfig
@@ -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
diff --git a/arch/sh/kernel/machine_kexec.c b/arch/sh/kernel/machine_kexec.c
index 25b4748fdc7..c44efb73ab1 100644
--- a/arch/sh/kernel/machine_kexec.c
+++ b/arch/sh/kernel/machine_kexec.c
@@ -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)
diff --git a/arch/sh/kernel/relocate_kernel.S b/arch/sh/kernel/relocate_kernel.S
index 2a6630be668..fcc9934fb97 100644
--- a/arch/sh/kernel/relocate_kernel.S
+++ b/arch/sh/kernel/relocate_kernel.S
@@ -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 */
+
+ /* 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 */
- /* stack setting */
- add r8,r5
- mov r5,r15
+ 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: