From: Geoff Levand <ge...@infradead.org>
Commit 68234df4ea79 ("arm64: kill flush_cache_all()")
removed the global arm64 routines cpu_reset() and cpu_soft_restart()
needed by the arm64 kexec and kdump support. Add simplified versions
of those two routines back with some changes needed for kexec in the
new files cpu_reset.S, and cpu_reset.h.
When a CPU is reset it needs to be put into the exception level it had
when it entered the kernel. Update cpu_reset() to accept an argument
which signals if the reset address needs to be entered at EL1 or EL2.
Signed-off-by: Geoff Levand <ge...@infradead.org>
---
arch/arm64/kernel/cpu-reset.S | 84 +++++++++++++++++++++++++++++++++++++++++++
arch/arm64/kernel/cpu-reset.h | 22 ++++++++++++
2 files changed, 106 insertions(+)
create mode 100644 arch/arm64/kernel/cpu-reset.S
create mode 100644 arch/arm64/kernel/cpu-reset.h
diff --git a/arch/arm64/kernel/cpu-reset.S b/arch/arm64/kernel/cpu-reset.S
new file mode 100644
index 0000000..0423f27
--- /dev/null
+++ b/arch/arm64/kernel/cpu-reset.S
@@ -0,0 +1,84 @@
+/*
+ * cpu reset routines
+ *
+ * Copyright (C) 2001 Deep Blue Solutions Ltd.
+ * Copyright (C) 2012 ARM Ltd.
+ * Copyright (C) 2015 Huawei Futurewei Technologies.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/linkage.h>
+#include <asm/assembler.h>
+#include <asm/virt.h>
+
+#define SCTLR_ELx_I (1 << 12)
+#define SCTLR_ELx_SA (1 << 3)
+#define SCTLR_ELx_C (1 << 2)
+#define SCTLR_ELx_A (1 << 1)
+#define SCTLR_ELx_M 1
+#define SCTLR_ELx_FLAGS (SCTLR_ELx_M | SCTLR_ELx_A | SCTLR_ELx_C |
\
+ SCTLR_ELx_SA | SCTLR_ELx_I)
+
+.text
+.pushsection .idmap.text, "ax"
+
+.align 5
+
+/*
+ * cpu_soft_restart(cpu_reset, el2_switch, entry, arg0, arg1) - Perform a cpu
+ * soft reset.
+ *
+ * @cpu_reset: Physical address of the cpu_reset routine.
+ * @el2_switch: Flag to indicate a swich to EL2 is needed, passed to cpu_reset.
+ * @entry: Location to jump to for soft reset, passed to cpu_reset.
+ * arg0: First argument passed to @entry.
+ * arg1: Second argument passed to @entry.
+ */
+
+ENTRY(cpu_soft_restart)
+ mov x18, x0 // cpu_reset
+ mov x0, x1 // el2_switch
+ mov x1, x2 // entry
+ mov x2, x3 // arg0
+ mov x3, x4 // arg1
+ ret x18
+ENDPROC(cpu_soft_restart)
+
+/*
+ * cpu_reset(el2_switch, entry, arg0, arg1) - Helper for cpu_soft_restart.
+ *
+ * @el2_switch: Flag to indicate a swich to EL2 is needed.
+ * @entry: Location to jump to for soft reset.
+ * arg0: First argument passed to @entry.
+ * arg1: Second argument passed to @entry.
+ *
+ * Put the CPU into the same state as it would be if it had been reset, and
+ * branch to what would be the reset vector. It must be executed with the
+ * flat identity mapping.
+ */
+
+ENTRY(cpu_reset)
+ /* Clear sctlr_el1 flags. */
+ mrs x12, sctlr_el1
+ ldr x13, =SCTLR_ELx_FLAGS
+ bic x12, x12, x13
+ msr sctlr_el1, x12
+ isb
+
+ cbz x0, 1f // el2_switch?
+
+ mov x0, x1 // entry
+ mov x1, x2 // arg0
+ mov x2, x3 // arg1
+ hvc #HVC_CALL_FUNC // no return
+
+1: mov x18, x1 // entry
+ mov x0, x2 // arg0
+ mov x1, x3 // arg1
+ ret x18
+ENDPROC(cpu_reset)
+
+.popsection
diff --git a/arch/arm64/kernel/cpu-reset.h b/arch/arm64/kernel/cpu-reset.h
new file mode 100644
index 0000000..79816b6
--- /dev/null
+++ b/arch/arm64/kernel/cpu-reset.h
@@ -0,0 +1,22 @@
+/*
+ * cpu reset routines
+ *
+ * Copyright (C) 2015 Huawei Futurewei Technologies.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#if !defined(_ARM64_CPU_RESET_H)
+#define _ARM64_CPU_RESET_H
+
+#include <asm/virt.h>
+
+void __attribute__((noreturn)) cpu_reset(unsigned long el2_switch,
+ unsigned long entry, unsigned long arg0, unsigned long arg1);
+void __attribute__((noreturn)) cpu_soft_restart(phys_addr_t cpu_reset,
+ unsigned long el2_switch, unsigned long entry, unsigned long arg0,
+ unsigned long arg1);
+
+#endif
--
2.7.4
--
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