--- /dev/null
+/*
+ * Copyright (c) 2012 Linaro Limited.
+ *
+ * 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; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#ifndef VIRT_H
+#define VIRT_H
+
+#include <asm/ptrace.h>
+
+/*
+ * Flag indicating that the kernel was not entered in the same mode on every
+ * CPU. The zImage loader stashes this value in an SPSR, so we need an
+ * architecturally defined flag bit here (the N flag, as it happens)
+ */
+#define BOOT_CPU_MODE_MISMATCH (1<<31)
+
+#ifndef __ASSEMBLY__
+
+#ifdef CONFIG_ARM_VIRT_EXT
+/*
+ * __boot_cpu_mode records what mode the primary CPU was booted in.
+ * A correctly-implemented bootloader must start all CPUs in the same mode:
+ * if it fails to do this, the flag BOOT_CPU_MODE_MISMATCH is set to indicate
+ * that some CPU(s) were booted in a different mode.
+ *
+ * This allows the kernel to flag an error when the secondaries have come up.
+ */
+extern int __boot_cpu_mode;
+
+void __hyp_set_vectors(unsigned long phys_vector_base);
+unsigned long __hyp_get_vectors(void);
+#else
+#define __boot_cpu_mode (SVC_MODE)
+#endif
+
+#endif /* __ASSEMBLY__ */
+
+#endif /* ! VIRT_H */
--- /dev/null
+/*
+ * Copyright (c) 2012 Linaro Limited.
+ *
+ * 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; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include <linux/init.h>
+#include <linux/linkage.h>
+#include <asm/assembler.h>
+#include <asm/virt.h>
+
+/*
+ * For the kernel proper, we need to find out the CPU boot mode long after
+ * boot, so we need to store it in a writable variable.
+ *
+ * This is not in .bss, because we set it sufficiently early that the boot-time
+ * zeroing of .bss would clobber it.
+ */
+.data
+ENTRY(__boot_cpu_mode)
+ .long 0
+.text
+
+ /*
+ * Save the primary CPU boot mode. Requires 3 scratch registers.
+ */
+ .macro store_primary_cpu_mode reg1, reg2, reg3
+ mrs \reg1, cpsr
+ and \reg1, \reg1, #MODE_MASK
+ adr \reg2, .L__boot_cpu_mode_offset
+ ldr \reg3, [\reg2]
+ str \reg1, [\reg2, \reg3]
+ .endm
+
+ /*
+ * Compare the current mode with the one saved on the primary CPU.
+ * If they don't match, record that fact. The Z bit indicates
+ * if there's a match or not.
+ * Requires 3 additionnal scratch registers.
+ */
+ .macro compare_cpu_mode_with_primary mode, reg1, reg2, reg3
+ adr \reg2, .L__boot_cpu_mode_offset
+ ldr \reg3, [\reg2]
+ ldr \reg1, [\reg2, \reg3]
+ cmp \mode, \reg1 @ matches primary CPU boot mode?
+ orrne r7, r7, #BOOT_CPU_MODE_MISMATCH
+ strne r7, [r5, r6] @ record what happened and give up
+ .endm
+
+/*
+ * Hypervisor stub installation functions.
+ *
+ * These must be called with the MMU and D-cache off.
+ * They are not ABI compliant and are only intended to be called from the kernel
+ * entry points in head.S.
+ */
+@ Call this from the primary CPU
+ENTRY(__hyp_stub_install)
+ store_primary_cpu_mode r4, r5, r6
+ENDPROC(__hyp_stub_install)
+
+ @ fall through...
+
+@ Secondary CPUs should call here
+ENTRY(__hyp_stub_install_secondary)
+ mrs r4, cpsr
+ and r4, r4, #MODE_MASK
+
+ /*
+ * If the secondary has booted with a different mode, give up
+ * immediately.
+ */
+ compare_cpu_mode_with_primary r4, r5, r6, r7
+ bxne lr
+
+ /*
+ * Once we have given up on one CPU, we do not try to install the
+ * stub hypervisor on the remaining ones: because the saved boot mode
+ * is modified, it can't compare equal to the CPSR mode field any
+ * more.
+ *
+ * Otherwise...
+ */
+
+ cmp r4, #HYP_MODE
+ bxne lr @ give up if the CPU is not in HYP mode
+
+/*
+ * Configure HSCTLR to set correct exception endianness/instruction set
+ * state etc.
+ * Turn off all traps
+ * Eventually, CPU-specific code might be needed -- assume not for now
+ *
+ * This code relies on the "eret" instruction to synchronize the
+ * various coprocessor accesses.
+ */
+ @ Now install the hypervisor stub:
+ adr r7, __hyp_stub_vectors
+ mcr p15, 4, r7, c12, c0, 0 @ set hypervisor vector base (HVBAR)
+
+ @ Disable all traps, so we don't get any nasty surprise
+ mov r7, #0
+ mcr p15, 4, r7, c1, c1, 0 @ HCR
+ mcr p15, 4, r7, c1, c1, 2 @ HCPTR
+ mcr p15, 4, r7, c1, c1, 3 @ HSTR
+
+THUMB( orr r7, #(1 << 30) ) @ HSCTLR.TE
+#ifdef CONFIG_CPU_BIG_ENDIAN
+ orr r7, #(1 << 9) @ HSCTLR.EE
+#endif
+ mcr p15, 4, r7, c1, c0, 0 @ HSCTLR
+
+ mrc p15, 4, r7, c1, c1, 1 @ HDCR
+ and r7, #0x1f @ Preserve HPMN
+ mcr p15, 4, r7, c1, c1, 1 @ HDCR
+
+ bic r7, r4, #MODE_MASK
+ orr r7, r7, #SVC_MODE
+THUMB( orr r7, r7, #PSR_T_BIT )
+ msr spsr_cxsf, r7 @ This is SPSR_hyp.
+
+ __MSR_ELR_HYP(14) @ msr elr_hyp, lr
+ __ERET @ return, switching to SVC mode
+ @ The boot CPU mode is left in r4.
+ENDPROC(__hyp_stub_install_secondary)
+
+__hyp_stub_do_trap:
+ cmp r0, #-1
+ mrceq p15, 4, r0, c12, c0, 0 @ get HVBAR
+ mcrne p15, 4, r0, c12, c0, 0 @ set HVBAR
+ __ERET
+ENDPROC(__hyp_stub_do_trap)
+
+/*
+ * __hyp_set_vectors: Call this after boot to set the initial hypervisor
+ * vectors as part of hypervisor installation. On an SMP system, this should
+ * be called on each CPU.
+ *
+ * r0 must be the physical address of the new vector table (which must lie in
+ * the bottom 4GB of physical address space.
+ *
+ * r0 must be 32-byte aligned.
+ *
+ * Before calling this, you must check that the stub hypervisor is installed
+ * everywhere, by waiting for any secondary CPUs to be brought up and then
+ * checking that BOOT_CPU_MODE_HAVE_HYP(__boot_cpu_mode) is true.
+ *
+ * If not, there is a pre-existing hypervisor, some CPUs failed to boot, or
+ * something else went wrong... in such cases, trying to install a new
+ * hypervisor is unlikely to work as desired.
+ *
+ * When you call into your shiny new hypervisor, sp_hyp will contain junk,
+ * so you will need to set that to something sensible at the new hypervisor's
+ * initialisation entry point.
+ */
+ENTRY(__hyp_get_vectors)
+ mov r0, #-1
+ENDPROC(__hyp_get_vectors)
+ @ fall through
+ENTRY(__hyp_set_vectors)
+ __HVC(0)
+ bx lr
+ENDPROC(__hyp_set_vectors)
+
+.align 2
+.L__boot_cpu_mode_offset:
+ .long __boot_cpu_mode - .
+
+.align 5
+__hyp_stub_vectors:
+__hyp_stub_reset: W(b) .
+__hyp_stub_und: W(b) .
+__hyp_stub_svc: W(b) .
+__hyp_stub_pabort: W(b) .
+__hyp_stub_dabort: W(b) .
+__hyp_stub_trap: W(b) __hyp_stub_do_trap
+__hyp_stub_irq: W(b) .
+__hyp_stub_fiq: W(b) .
+ENDPROC(__hyp_stub_vectors)
+
projects / linux-beck.git / commitdiff