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linux/arch/arm/kernel/asm-offsets.c
Christoffer Dall f7ed45be3b KVM: ARM: World-switch implementation 
Provides complete world-switch implementation to switch to other guests
running in non-secure modes. Includes Hyp exception handlers that
capture necessary exception information and stores the information on
the VCPU and KVM structures.

The following Hyp-ABI is also documented in the code:

Hyp-ABI: Calling HYP-mode functions from host (in SVC mode):
   Switching to Hyp mode is done through a simple HVC #0 instruction. The
   exception vector code will check that the HVC comes from VMID==0 and if
   so will push the necessary state (SPSR, lr_usr) on the Hyp stack.
   - r0 contains a pointer to a HYP function
   - r1, r2, and r3 contain arguments to the above function.
   - The HYP function will be called with its arguments in r0, r1 and r2.
   On HYP function return, we return directly to SVC.

A call to a function executing in Hyp mode is performed like the following:

        <svc code>
        ldr     r0, =BSYM(my_hyp_fn)
        ldr     r1, =my_param
        hvc #0  ; Call my_hyp_fn(my_param) from HYP mode
        <svc code>

Otherwise, the world-switch is pretty straight-forward. All state that
can be modified by the guest is first backed up on the Hyp stack and the
VCPU values is loaded onto the hardware. State, which is not loaded, but
theoretically modifiable by the guest is protected through the
virtualiation features to generate a trap and cause software emulation.
Upon guest returns, all state is restored from hardware onto the VCPU
struct and the original state is restored from the Hyp-stack onto the
hardware.

SMP support using the VMPIDR calculated on the basis of the host MPIDR
and overriding the low bits with KVM vcpu_id contributed by Marc Zyngier.

Reuse of VMIDs has been implemented by Antonios Motakis and adapated from
a separate patch into the appropriate patches introducing the
functionality. Note that the VMIDs are stored per VM as required by the ARM
architecture reference manual.

To support VFP/NEON we trap those instructions using the HPCTR. When
we trap, we switch the FPU.  After a guest exit, the VFP state is
returned to the host.  When disabling access to floating point
instructions, we also mask FPEXC_EN in order to avoid the guest
receiving Undefined instruction exceptions before we have a chance to
switch back the floating point state.  We are reusing vfp_hard_struct,
so we depend on VFPv3 being enabled in the host kernel, if not, we still
trap cp10 and cp11 in order to inject an undefined instruction exception
whenever the guest tries to use VFP/NEON. VFP/NEON developed by
Antionios Motakis and Rusty Russell.

Aborts that are permission faults, and not stage-1 page table walk, do
not report the faulting address in the HPFAR.  We have to resolve the
IPA, and store it just like the HPFAR register on the VCPU struct. If
the IPA cannot be resolved, it means another CPU is playing with the
page tables, and we simply restart the guest.  This quirk was fixed by
Marc Zyngier.

Reviewed-by: Will Deacon <will.deacon@arm.com>
Reviewed-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Antonios Motakis <a.motakis@virtualopensystems.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <c.dall@virtualopensystems.com>
2013-01-23 13:29:12 -05:00

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/*
* Copyright (C) 1995-2003 Russell King
* 2001-2002 Keith Owens
*
* Generate definitions needed by assembly language modules.
* This code generates raw asm output which is post-processed to extract
* and format the required data.
*
* 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/sched.h>
#include <linux/mm.h>
#include <linux/dma-mapping.h>
#ifdef CONFIG_KVM_ARM_HOST
#include <linux/kvm_host.h>
#endif
#include <asm/cacheflush.h>
#include <asm/glue-df.h>
#include <asm/glue-pf.h>
#include <asm/mach/arch.h>
#include <asm/thread_info.h>
#include <asm/memory.h>
#include <asm/procinfo.h>
#include <asm/hardware/cache-l2x0.h>
#include <linux/kbuild.h>
/*
* Make sure that the compiler and target are compatible.
*/
#if defined(__APCS_26__)
#error Sorry, your compiler targets APCS-26 but this kernel requires APCS-32
#endif
/*
* GCC 3.0, 3.1: general bad code generation.
* GCC 3.2.0: incorrect function argument offset calculation.
* GCC 3.2.x: miscompiles NEW_AUX_ENT in fs/binfmt_elf.c
* (http://gcc.gnu.org/PR8896) and incorrect structure
* initialisation in fs/jffs2/erase.c
*/
#if (__GNUC__ == 3 && __GNUC_MINOR__ < 3)
#error Your compiler is too buggy; it is known to miscompile kernels.
#error Known good compilers: 3.3
#endif
int main(void)
{
DEFINE(TSK_ACTIVE_MM, offsetof(struct task_struct, active_mm));
#ifdef CONFIG_CC_STACKPROTECTOR
DEFINE(TSK_STACK_CANARY, offsetof(struct task_struct, stack_canary));
#endif
BLANK();
DEFINE(TI_FLAGS, offsetof(struct thread_info, flags));
DEFINE(TI_PREEMPT, offsetof(struct thread_info, preempt_count));
DEFINE(TI_ADDR_LIMIT, offsetof(struct thread_info, addr_limit));
DEFINE(TI_TASK, offsetof(struct thread_info, task));
DEFINE(TI_EXEC_DOMAIN, offsetof(struct thread_info, exec_domain));
DEFINE(TI_CPU, offsetof(struct thread_info, cpu));
DEFINE(TI_CPU_DOMAIN, offsetof(struct thread_info, cpu_domain));
DEFINE(TI_CPU_SAVE, offsetof(struct thread_info, cpu_context));
DEFINE(TI_USED_CP, offsetof(struct thread_info, used_cp));
DEFINE(TI_TP_VALUE, offsetof(struct thread_info, tp_value));
DEFINE(TI_FPSTATE, offsetof(struct thread_info, fpstate));
#ifdef CONFIG_VFP
DEFINE(TI_VFPSTATE, offsetof(struct thread_info, vfpstate));
#ifdef CONFIG_SMP
DEFINE(VFP_CPU, offsetof(union vfp_state, hard.cpu));
#endif
#endif
#ifdef CONFIG_ARM_THUMBEE
DEFINE(TI_THUMBEE_STATE, offsetof(struct thread_info, thumbee_state));
#endif
#ifdef CONFIG_IWMMXT
DEFINE(TI_IWMMXT_STATE, offsetof(struct thread_info, fpstate.iwmmxt));
#endif
#ifdef CONFIG_CRUNCH
DEFINE(TI_CRUNCH_STATE, offsetof(struct thread_info, crunchstate));
#endif
BLANK();
DEFINE(S_R0, offsetof(struct pt_regs, ARM_r0));
DEFINE(S_R1, offsetof(struct pt_regs, ARM_r1));
DEFINE(S_R2, offsetof(struct pt_regs, ARM_r2));
DEFINE(S_R3, offsetof(struct pt_regs, ARM_r3));
DEFINE(S_R4, offsetof(struct pt_regs, ARM_r4));
DEFINE(S_R5, offsetof(struct pt_regs, ARM_r5));
DEFINE(S_R6, offsetof(struct pt_regs, ARM_r6));
DEFINE(S_R7, offsetof(struct pt_regs, ARM_r7));
DEFINE(S_R8, offsetof(struct pt_regs, ARM_r8));
DEFINE(S_R9, offsetof(struct pt_regs, ARM_r9));
DEFINE(S_R10, offsetof(struct pt_regs, ARM_r10));
DEFINE(S_FP, offsetof(struct pt_regs, ARM_fp));
DEFINE(S_IP, offsetof(struct pt_regs, ARM_ip));
DEFINE(S_SP, offsetof(struct pt_regs, ARM_sp));
DEFINE(S_LR, offsetof(struct pt_regs, ARM_lr));
DEFINE(S_PC, offsetof(struct pt_regs, ARM_pc));
DEFINE(S_PSR, offsetof(struct pt_regs, ARM_cpsr));
DEFINE(S_OLD_R0, offsetof(struct pt_regs, ARM_ORIG_r0));
DEFINE(S_FRAME_SIZE, sizeof(struct pt_regs));
BLANK();
#ifdef CONFIG_CACHE_L2X0
DEFINE(L2X0_R_PHY_BASE, offsetof(struct l2x0_regs, phy_base));
DEFINE(L2X0_R_AUX_CTRL, offsetof(struct l2x0_regs, aux_ctrl));
DEFINE(L2X0_R_TAG_LATENCY, offsetof(struct l2x0_regs, tag_latency));
DEFINE(L2X0_R_DATA_LATENCY, offsetof(struct l2x0_regs, data_latency));
DEFINE(L2X0_R_FILTER_START, offsetof(struct l2x0_regs, filter_start));
DEFINE(L2X0_R_FILTER_END, offsetof(struct l2x0_regs, filter_end));
DEFINE(L2X0_R_PREFETCH_CTRL, offsetof(struct l2x0_regs, prefetch_ctrl));
DEFINE(L2X0_R_PWR_CTRL, offsetof(struct l2x0_regs, pwr_ctrl));
BLANK();
#endif
#ifdef CONFIG_CPU_HAS_ASID
DEFINE(MM_CONTEXT_ID, offsetof(struct mm_struct, context.id));
BLANK();
#endif
DEFINE(VMA_VM_MM, offsetof(struct vm_area_struct, vm_mm));
DEFINE(VMA_VM_FLAGS, offsetof(struct vm_area_struct, vm_flags));
BLANK();
DEFINE(VM_EXEC, VM_EXEC);
BLANK();
DEFINE(PAGE_SZ, PAGE_SIZE);
BLANK();
DEFINE(SYS_ERROR0, 0x9f0000);
BLANK();
DEFINE(SIZEOF_MACHINE_DESC, sizeof(struct machine_desc));
DEFINE(MACHINFO_TYPE, offsetof(struct machine_desc, nr));
DEFINE(MACHINFO_NAME, offsetof(struct machine_desc, name));
BLANK();
DEFINE(PROC_INFO_SZ, sizeof(struct proc_info_list));
DEFINE(PROCINFO_INITFUNC, offsetof(struct proc_info_list, __cpu_flush));
DEFINE(PROCINFO_MM_MMUFLAGS, offsetof(struct proc_info_list, __cpu_mm_mmu_flags));
DEFINE(PROCINFO_IO_MMUFLAGS, offsetof(struct proc_info_list, __cpu_io_mmu_flags));
BLANK();
#ifdef MULTI_DABORT
DEFINE(PROCESSOR_DABT_FUNC, offsetof(struct processor, _data_abort));
#endif
#ifdef MULTI_PABORT
DEFINE(PROCESSOR_PABT_FUNC, offsetof(struct processor, _prefetch_abort));
#endif
#ifdef MULTI_CPU
DEFINE(CPU_SLEEP_SIZE, offsetof(struct processor, suspend_size));
DEFINE(CPU_DO_SUSPEND, offsetof(struct processor, do_suspend));
DEFINE(CPU_DO_RESUME, offsetof(struct processor, do_resume));
#endif
#ifdef MULTI_CACHE
DEFINE(CACHE_FLUSH_KERN_ALL, offsetof(struct cpu_cache_fns, flush_kern_all));
#endif
BLANK();
DEFINE(DMA_BIDIRECTIONAL, DMA_BIDIRECTIONAL);
DEFINE(DMA_TO_DEVICE, DMA_TO_DEVICE);
DEFINE(DMA_FROM_DEVICE, DMA_FROM_DEVICE);
#ifdef CONFIG_KVM_ARM_HOST
DEFINE(VCPU_KVM, offsetof(struct kvm_vcpu, kvm));
DEFINE(VCPU_MIDR, offsetof(struct kvm_vcpu, arch.midr));
DEFINE(VCPU_CP15, offsetof(struct kvm_vcpu, arch.cp15));
DEFINE(VCPU_VFP_GUEST, offsetof(struct kvm_vcpu, arch.vfp_guest));
DEFINE(VCPU_VFP_HOST, offsetof(struct kvm_vcpu, arch.vfp_host));
DEFINE(VCPU_REGS, offsetof(struct kvm_vcpu, arch.regs));
DEFINE(VCPU_USR_REGS, offsetof(struct kvm_vcpu, arch.regs.usr_regs));
DEFINE(VCPU_SVC_REGS, offsetof(struct kvm_vcpu, arch.regs.svc_regs));
DEFINE(VCPU_ABT_REGS, offsetof(struct kvm_vcpu, arch.regs.abt_regs));
DEFINE(VCPU_UND_REGS, offsetof(struct kvm_vcpu, arch.regs.und_regs));
DEFINE(VCPU_IRQ_REGS, offsetof(struct kvm_vcpu, arch.regs.irq_regs));
DEFINE(VCPU_FIQ_REGS, offsetof(struct kvm_vcpu, arch.regs.fiq_regs));
DEFINE(VCPU_PC, offsetof(struct kvm_vcpu, arch.regs.usr_regs.ARM_pc));
DEFINE(VCPU_CPSR, offsetof(struct kvm_vcpu, arch.regs.usr_regs.ARM_cpsr));
DEFINE(VCPU_IRQ_LINES, offsetof(struct kvm_vcpu, arch.irq_lines));
DEFINE(VCPU_HSR, offsetof(struct kvm_vcpu, arch.hsr));
DEFINE(VCPU_HxFAR, offsetof(struct kvm_vcpu, arch.hxfar));
DEFINE(VCPU_HPFAR, offsetof(struct kvm_vcpu, arch.hpfar));
DEFINE(VCPU_HYP_PC, offsetof(struct kvm_vcpu, arch.hyp_pc));
DEFINE(KVM_VTTBR, offsetof(struct kvm, arch.vttbr));
#endif
return 0;
}
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