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Message-Id: <1480423554-6411-7-git-send-email-mpe@ellerman.id.au>
Date: Tue, 29 Nov 2016 23:45:52 +1100
From: Michael Ellerman <mpe@...erman.id.au>
To: linuxppc-dev@...abs.org
Cc: linux-kernel@...r.kernel.org, akpm@...ux-foundation.org,
dyoung@...hat.com, stewart@...ux.vnet.ibm.com,
bauerman@...ux.vnet.ibm.com
Subject: [PATCH v11 6/8] powerpc: Add purgatory for kexec_file_load() implementation.
From: Thiago Jung Bauermann <bauerman@...ux.vnet.ibm.com>
This purgatory implementation is based on the versions from kexec-tools
and kexec-lite, with additional changes.
Signed-off-by: Thiago Jung Bauermann <bauerman@...ux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@...erman.id.au>
---
arch/powerpc/Makefile | 1 +
arch/powerpc/kernel/machine_kexec_64.c | 2 +-
arch/powerpc/purgatory/.gitignore | 2 +
arch/powerpc/purgatory/Makefile | 15 ++++
arch/powerpc/purgatory/trampoline.S | 128 +++++++++++++++++++++++++++++++++
5 files changed, 147 insertions(+), 1 deletion(-)
create mode 100644 arch/powerpc/purgatory/.gitignore
create mode 100644 arch/powerpc/purgatory/Makefile
create mode 100644 arch/powerpc/purgatory/trampoline.S
diff --git a/arch/powerpc/Makefile b/arch/powerpc/Makefile
index 617dece67924..5e7dcdaf93f5 100644
--- a/arch/powerpc/Makefile
+++ b/arch/powerpc/Makefile
@@ -249,6 +249,7 @@ 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-$(CONFIG_OPROFILE) += arch/powerpc/oprofile/
diff --git a/arch/powerpc/kernel/machine_kexec_64.c b/arch/powerpc/kernel/machine_kexec_64.c
index a205fa3d9bf3..5c12e21d0d1a 100644
--- a/arch/powerpc/kernel/machine_kexec_64.c
+++ b/arch/powerpc/kernel/machine_kexec_64.c
@@ -310,7 +310,7 @@ void default_machine_kexec(struct kimage *image)
if (!kdump_in_progress())
kexec_prepare_cpus();
- pr_debug("kexec: Starting switchover sequence.\n");
+ printk("kexec: Starting switchover sequence.\n");
/* switch to a staticly allocated stack. Based on irq stack code.
* We setup preempt_count to avoid using VMX in memcpy.
diff --git a/arch/powerpc/purgatory/.gitignore b/arch/powerpc/purgatory/.gitignore
new file mode 100644
index 000000000000..e9e66f178a6d
--- /dev/null
+++ b/arch/powerpc/purgatory/.gitignore
@@ -0,0 +1,2 @@
+kexec-purgatory.c
+purgatory.ro
diff --git a/arch/powerpc/purgatory/Makefile b/arch/powerpc/purgatory/Makefile
new file mode 100644
index 000000000000..ac8793c13348
--- /dev/null
+++ b/arch/powerpc/purgatory/Makefile
@@ -0,0 +1,15 @@
+targets += trampoline.o purgatory.ro kexec-purgatory.c
+
+LDFLAGS_purgatory.ro := -e purgatory_start -r --no-undefined
+
+$(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
index 000000000000..f9760ccf4032
--- /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
--
2.7.4
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