/* * 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> #ifndef ZIMAGE /* * 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 #else /* ZIMAGE */ .macro store_primary_cpu_mode reg1:req, reg2:req, reg3:req .endm /* * The zImage loader only runs on one CPU, so we don't bother with mult-CPU * consistency checking: */ .macro compare_cpu_mode_with_primary mode, reg1, reg2, reg3 cmp \mode, \mode .endm #endif /* ZIMAGE */ /* * 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 movne pc, 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 movne pc, 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. This is done when we switch to SVC * (see safe_svcmode_maskall). */ @ 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 #if !defined(ZIMAGE) && defined(CONFIG_ARM_ARCH_TIMER) @ make CNTP_* and CNTPCT accessible from PL1 mrc p15, 0, r7, c0, c1, 1 @ ID_PFR1 lsr r7, #16 and r7, #0xf cmp r7, #1 bne 1f mrc p15, 4, r7, c14, c1, 0 @ CNTHCTL orr r7, r7, #3 @ PL1PCEN | PL1PCTEN mcr p15, 4, r7, c14, c1, 0 @ CNTHCTL 1: #endif bx lr @ 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) mov pc, lr ENDPROC(__hyp_set_vectors) #ifndef ZIMAGE .align 2 .L__boot_cpu_mode_offset: .long __boot_cpu_mode - . #endif .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)