powerpc: Add purgatory for kexec_file_load() implementation.

This purgatory implementation is based on the versions from kexec-tools
and kexec-lite, with additional changes.

Signed-off-by: Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

diff --git a/arch/powerpc/Makefile b/arch/powerpc/Makefile
index 82ce8c8..31286fa 100644 (file)
--- a/arch/powerpc/Makefile
+++ b/arch/powerpc/Makefile
@@ -250,6 +250,7 @@ core-y                              += arch/powerpc/kernel/ \
 core-$(CONFIG_XMON)            += arch/powerpc/xmon/
 core-$(CONFIG_KVM)             += arch/powerpc/kvm/
 core-$(CONFIG_PERF_EVENTS)     += arch/powerpc/perf/
+core-$(CONFIG_KEXEC_FILE)      += arch/powerpc/purgatory/
 
 drivers-$(CONFIG_OPROFILE)     += arch/powerpc/oprofile/
 

diff --git a/arch/powerpc/kernel/machine_kexec_64.c b/arch/powerpc/kernel/machine_kexec_64.c
index a205fa3..5c12e21 100644 (file)
--- a/arch/powerpc/kernel/machine_kexec_64.c
+++ b/arch/powerpc/kernel/machine_kexec_64.c
@@ -310,7 +310,7 @@ void default_machine_kexec(struct kimage *image)
        if (!kdump_in_progress())
                kexec_prepare_cpus();
 
-       pr_debug("kexec: Starting switchover sequence.\n");
+       printk("kexec: Starting switchover sequence.\n");
 
        /* switch to a staticly allocated stack.  Based on irq stack code.
         * We setup preempt_count to avoid using VMX in memcpy.

diff --git a/arch/powerpc/purgatory/.gitignore b/arch/powerpc/purgatory/.gitignore
new file mode 100644 (file)
index 0000000..e9e66f1
--- /dev/null
+++ b/arch/powerpc/purgatory/.gitignore
@@ -0,0 +1,2 @@
+kexec-purgatory.c
+purgatory.ro

diff --git a/arch/powerpc/purgatory/Makefile b/arch/powerpc/purgatory/Makefile
new file mode 100644 (file)
index 0000000..ac8793c
--- /dev/null
+++ b/arch/powerpc/purgatory/Makefile
@@ -0,0 +1,15 @@
+targets += trampoline.o purgatory.ro kexec-purgatory.c
+
+LDFLAGS_purgatory.ro := -e purgatory_start -r --no-undefined
+
+$(obj)/purgatory.ro: $(obj)/trampoline.o FORCE
+               $(call if_changed,ld)
+
+CMD_BIN2C = $(objtree)/scripts/basic/bin2c
+quiet_cmd_bin2c = BIN2C   $@
+      cmd_bin2c = $(CMD_BIN2C) kexec_purgatory < $< > $@
+
+$(obj)/kexec-purgatory.c: $(obj)/purgatory.ro FORCE
+       $(call if_changed,bin2c)
+
+obj-y  += kexec-purgatory.o

diff --git a/arch/powerpc/purgatory/trampoline.S b/arch/powerpc/purgatory/trampoline.S
new file mode 100644 (file)
index 0000000..f9760cc
--- /dev/null
+++ b/arch/powerpc/purgatory/trampoline.S
@@ -0,0 +1,128 @@
+/*
+ * kexec trampoline
+ *
+ * Based on code taken from kexec-tools and kexec-lite.
+ *
+ * Copyright (C) 2004 - 2005, Milton D Miller II, IBM Corporation
+ * Copyright (C) 2006, Mohan Kumar M, IBM Corporation
+ * Copyright (C) 2013, Anton Blanchard, IBM Corporation
+ *
+ * This program is free software; you can redistribute it and/or modify it under
+ * the terms of the GNU General Public License as published by the Free
+ * Software Foundation (version 2 of the License).
+ */
+
+#if defined(__LITTLE_ENDIAN__)
+#define STWX_BE        stwbrx
+#define LWZX_BE        lwbrx
+#elif defined(__BIG_ENDIAN__)
+#define STWX_BE        stwx
+#define LWZX_BE        lwzx
+#else
+#error no endianness defined!
+#endif
+
+       .machine ppc64
+       .balign 256
+       .globl purgatory_start
+purgatory_start:
+       b       master
+
+       /* ABI: possible run_at_load flag at 0x5c */
+       .org purgatory_start + 0x5c
+       .globl run_at_load
+run_at_load:
+       .long 0
+       .size run_at_load, . - run_at_load
+
+       /* ABI: slaves start at 60 with r3=phys */
+       .org purgatory_start + 0x60
+slave:
+       b .
+       /* ABI: end of copied region */
+       .org purgatory_start + 0x100
+       .size purgatory_start, . - purgatory_start
+
+/*
+ * The above 0x100 bytes at purgatory_start are replaced with the
+ * code from the kernel (or next stage) by setup_purgatory().
+ */
+
+master:
+       or      %r1,%r1,%r1     /* low priority to let other threads catchup */
+       isync
+       mr      %r17,%r3        /* save cpu id to r17 */
+       mr      %r15,%r4        /* save physical address in reg15 */
+
+       or      %r3,%r3,%r3     /* ok now to high priority, lets boot */
+       lis     %r6,0x1
+       mtctr   %r6             /* delay a bit for slaves to catch up */
+       bdnz    .               /* before we overwrite 0-100 again */
+
+       bl      0f              /* Work out where we're running */
+0:     mflr    %r18
+
+       /* load device-tree address */
+       ld      %r3, (dt_offset - 0b)(%r18)
+       mr      %r16,%r3        /* save dt address in reg16 */
+       li      %r4,20
+       LWZX_BE %r6,%r3,%r4     /* fetch __be32 version number at byte 20 */
+       cmpwi   %r0,%r6,2       /* v2 or later? */
+       blt     1f
+       li      %r4,28
+       STWX_BE %r17,%r3,%r4    /* Store my cpu as __be32 at byte 28 */
+1:
+       /* load the kernel address */
+       ld      %r4,(kernel - 0b)(%r18)
+
+       /* load the run_at_load flag */
+       /* possibly patched by kexec */
+       ld      %r6,(run_at_load - 0b)(%r18)
+       /* and patch it into the kernel */
+       stw     %r6,(0x5c)(%r4)
+
+       mr      %r3,%r16        /* restore dt address */
+
+       li      %r5,0           /* r5 will be 0 for kernel */
+
+       mfmsr   %r11
+       andi.   %r10,%r11,1     /* test MSR_LE */
+       bne     .Little_endian
+
+       mtctr   %r4             /* prepare branch to */
+       bctr                    /* start kernel */
+
+.Little_endian:
+       mtsrr0  %r4             /* prepare branch to */
+
+       clrrdi  %r11,%r11,1     /* clear MSR_LE */
+       mtsrr1  %r11
+
+       rfid                    /* update MSR and start kernel */
+
+
+       .balign 8
+       .globl kernel
+kernel:
+       .llong  0x0
+       .size kernel, . - kernel
+
+       .balign 8
+       .globl dt_offset
+dt_offset:
+       .llong  0x0
+       .size dt_offset, . - dt_offset
+
+
+       .data
+       .balign 8
+.globl sha256_digest
+sha256_digest:
+       .skip   32
+       .size sha256_digest, . - sha256_digest
+
+       .balign 8
+.globl sha_regions
+sha_regions:
+       .skip   8 * 2 * 16
+       .size sha_regions, . - sha_regions