[PATCH v5 3/3] KVM/arm/arm64: enable enhanced armv8 fp/simd lazy switch
Christoffer Dall
christoffer.dall at linaro.org
Fri Dec 18 23:45:38 PST 2015
On Fri, Dec 18, 2015 at 05:17:00PM -0800, Mario Smarduch wrote:
> On 12/18/2015 5:54 AM, Christoffer Dall wrote:
> > On Sun, Dec 06, 2015 at 05:07:14PM -0800, Mario Smarduch wrote:
> >> This patch tracks armv7 and armv8 fp/simd hardware state with cptr_el2 register.
> >> On vcpu_load for 32 bit guests enable FP access, and enable fp/simd
> >> trapping for 32 and 64 bit guests. On first fp/simd access trap to handler
> >> to save host and restore guest context, and clear trapping bits to enable vcpu
> >> lazy mode. On vcpu_put if trap bits are clear save guest and restore host
> >> context and also save 32 bit guest fpexc register.
> >>
> >> Signed-off-by: Mario Smarduch <m.smarduch at samsung.com>
> >> ---
> >> arch/arm/include/asm/kvm_emulate.h | 5 ++
> >> arch/arm/include/asm/kvm_host.h | 2 +
> >> arch/arm/kvm/arm.c | 20 +++++--
> >> arch/arm64/include/asm/kvm_asm.h | 2 +
> >> arch/arm64/include/asm/kvm_emulate.h | 15 +++--
> >> arch/arm64/include/asm/kvm_host.h | 16 +++++-
> >> arch/arm64/kernel/asm-offsets.c | 1 +
> >> arch/arm64/kvm/Makefile | 3 +-
> >> arch/arm64/kvm/fpsimd_switch.S | 38 ++++++++++++
> >> arch/arm64/kvm/hyp.S | 108 +++++++++++++----------------------
> >> arch/arm64/kvm/hyp_head.S | 48 ++++++++++++++++
> >> 11 files changed, 181 insertions(+), 77 deletions(-)
> >> create mode 100644 arch/arm64/kvm/fpsimd_switch.S
> >> create mode 100644 arch/arm64/kvm/hyp_head.S
> >>
> >> diff --git a/arch/arm/include/asm/kvm_emulate.h b/arch/arm/include/asm/kvm_emulate.h
> >> index 3de11a2..13feed5 100644
> >> --- a/arch/arm/include/asm/kvm_emulate.h
> >> +++ b/arch/arm/include/asm/kvm_emulate.h
> >> @@ -243,6 +243,11 @@ static inline unsigned long vcpu_data_host_to_guest(struct kvm_vcpu *vcpu,
> >> }
> >> }
> >>
> >> +static inline bool kvm_guest_vcpu_is_32bit(struct kvm_vcpu *vcpu)
> >> +{
> >> + return true;
> >> +}
> >> +
> >> #ifdef CONFIG_VFPv3
> >> /* Called from vcpu_load - save fpexc and enable guest access to fp/simd unit */
> >> static inline void kvm_enable_vcpu_fpexc(struct kvm_vcpu *vcpu)
> >> diff --git a/arch/arm/include/asm/kvm_host.h b/arch/arm/include/asm/kvm_host.h
> >> index ecc883a..720ae51 100644
> >> --- a/arch/arm/include/asm/kvm_host.h
> >> +++ b/arch/arm/include/asm/kvm_host.h
> >> @@ -227,6 +227,8 @@ int kvm_perf_teardown(void);
> >> void kvm_mmu_wp_memory_region(struct kvm *kvm, int slot);
> >>
> >> struct kvm_vcpu *kvm_mpidr_to_vcpu(struct kvm *kvm, unsigned long mpidr);
> >> +
> >> +static inline void kvm_save_guest_vcpu_fpexc(struct kvm_vcpu *vcpu) {}
> >> void kvm_restore_host_vfp_state(struct kvm_vcpu *);
> >>
> >> static inline void kvm_arch_hardware_disable(void) {}
> >> diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c
> >> index 1de07ab..dd59f8a 100644
> >> --- a/arch/arm/kvm/arm.c
> >> +++ b/arch/arm/kvm/arm.c
> >> @@ -292,8 +292,12 @@ void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
> >>
> >> kvm_arm_set_running_vcpu(vcpu);
> >>
> >> - /* Save and enable FPEXC before we load guest context */
> >> - kvm_enable_vcpu_fpexc(vcpu);
> >> + /*
> >> + * For 32bit guest executing on arm64, enable fp/simd access in
> >> + * EL2. On arm32 save host fpexc and then enable fp/simd access.
> >> + */
> >> + if (kvm_guest_vcpu_is_32bit(vcpu))
> >> + kvm_enable_vcpu_fpexc(vcpu);
> >>
> >> /* reset hyp cptr register to trap on tracing and vfp/simd access*/
> >> vcpu_reset_cptr(vcpu);
> >> @@ -302,10 +306,18 @@ void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
> >> void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu)
> >> {
> >> /* If the fp/simd registers are dirty save guest, restore host. */
> >> - if (kvm_vcpu_vfp_isdirty(vcpu))
> >> + if (kvm_vcpu_vfp_isdirty(vcpu)) {
> >> kvm_restore_host_vfp_state(vcpu);
> >>
> >> - /* Restore host FPEXC trashed in vcpu_load */
> >> + /*
> >> + * For 32bit guest on arm64 save the guest fpexc register
> >> + * in EL2 mode.
> >> + */
> >> + if (kvm_guest_vcpu_is_32bit(vcpu))
> >> + kvm_save_guest_vcpu_fpexc(vcpu);
> >> + }
> >> +
> >> + /* For arm32 restore host FPEXC trashed in vcpu_load. */
> >> kvm_restore_host_fpexc(vcpu);
> >>
> >> /*
> >> diff --git a/arch/arm64/include/asm/kvm_asm.h b/arch/arm64/include/asm/kvm_asm.h
> >> index 5e37710..d53d069 100644
> >> --- a/arch/arm64/include/asm/kvm_asm.h
> >> +++ b/arch/arm64/include/asm/kvm_asm.h
> >> @@ -117,6 +117,8 @@ extern char __kvm_hyp_vector[];
> >> extern void __kvm_flush_vm_context(void);
> >> extern void __kvm_tlb_flush_vmid_ipa(struct kvm *kvm, phys_addr_t ipa);
> >> extern void __kvm_tlb_flush_vmid(struct kvm *kvm);
> >> +extern void __kvm_vcpu_enable_fpexc32(void);
> >> +extern void __kvm_vcpu_save_fpexc32(struct kvm_vcpu *vcpu);
> >>
> >> extern int __kvm_vcpu_run(struct kvm_vcpu *vcpu);
> >>
> >> diff --git a/arch/arm64/include/asm/kvm_emulate.h b/arch/arm64/include/asm/kvm_emulate.h
> >> index 8dccbd7..bbbee9d 100644
> >> --- a/arch/arm64/include/asm/kvm_emulate.h
> >> +++ b/arch/arm64/include/asm/kvm_emulate.h
> >> @@ -290,13 +290,20 @@ static inline unsigned long vcpu_data_host_to_guest(struct kvm_vcpu *vcpu,
> >> return data; /* Leave LE untouched */
> >> }
> >>
> >> -static inline void kvm_enable_vcpu_fpexc(struct kvm_vcpu *vcpu) {}
> >> -static inline void kvm_restore_host_fpexc(struct kvm_vcpu *vcpu) {}
> >> -static inline void vcpu_reset_cptr(struct kvm_vcpu *vcpu) {}
> >> +static inline bool kvm_guest_vcpu_is_32bit(struct kvm_vcpu *vcpu)
> >> +{
> >> + return !(vcpu->arch.hcr_el2 & HCR_RW);
> >> +}
> >> +
> >> +static inline void vcpu_reset_cptr(struct kvm_vcpu *vcpu)
> >> +{
> >> + vcpu->arch.cptr_el2 = CPTR_EL2_TTA | CPTR_EL2_TFP;
> >> +}
> >> +
> >>
> >> static inline bool kvm_vcpu_vfp_isdirty(struct kvm_vcpu *vcpu)
> >> {
> >> - return false;
> >> + return !!(~vcpu->arch.cptr_el2 & CPTR_EL2_TFP);
> >> }
> >>
> >> #endif /* __ARM64_KVM_EMULATE_H__ */
> >> diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
> >> index e16fd39..0c65393 100644
> >> --- a/arch/arm64/include/asm/kvm_host.h
> >> +++ b/arch/arm64/include/asm/kvm_host.h
> >> @@ -100,6 +100,7 @@ struct kvm_vcpu_arch {
> >> /* HYP configuration */
> >> u64 hcr_el2;
> >> u32 mdcr_el2;
> >> + u32 cptr_el2;
> >>
> >> /* Exception Information */
> >> struct kvm_vcpu_fault_info fault;
> >> @@ -248,7 +249,20 @@ static inline void kvm_arch_hardware_unsetup(void) {}
> >> static inline void kvm_arch_sync_events(struct kvm *kvm) {}
> >> static inline void kvm_arch_vcpu_uninit(struct kvm_vcpu *vcpu) {}
> >> static inline void kvm_arch_sched_in(struct kvm_vcpu *vcpu, int cpu) {}
> >> -static inline void kvm_restore_host_vfp_state(struct kvm_vcpu *vcpu) {}
> >> +
> >> +static inline void kvm_enable_vcpu_fpexc(struct kvm_vcpu *vcpu)
> >> +{
> >> + /* Enable FP/SIMD access from EL2 mode*/
> >> + kvm_call_hyp(__kvm_vcpu_enable_fpexc32);
> >> +}
> >> +
> >> +static inline void kvm_save_guest_vcpu_fpexc(struct kvm_vcpu *vcpu)
> >> +{
> >> + /* Save FPEXEC32_EL2 in EL2 mode */
> >> + kvm_call_hyp(__kvm_vcpu_save_fpexc32, vcpu);
> >> +}
> >> +static inline void kvm_restore_host_fpexc(struct kvm_vcpu *vcpu) {}
> >> +void kvm_restore_host_vfp_state(struct kvm_vcpu *vcpu);
> >>
> >> void kvm_arm_init_debug(void);
> >> void kvm_arm_setup_debug(struct kvm_vcpu *vcpu);
> >> diff --git a/arch/arm64/kernel/asm-offsets.c b/arch/arm64/kernel/asm-offsets.c
> >> index 8d89cf8..3c8d836 100644
> >> --- a/arch/arm64/kernel/asm-offsets.c
> >> +++ b/arch/arm64/kernel/asm-offsets.c
> >> @@ -123,6 +123,7 @@ int main(void)
> >> DEFINE(DEBUG_WVR, offsetof(struct kvm_guest_debug_arch, dbg_wvr));
> >> DEFINE(VCPU_HCR_EL2, offsetof(struct kvm_vcpu, arch.hcr_el2));
> >> DEFINE(VCPU_MDCR_EL2, offsetof(struct kvm_vcpu, arch.mdcr_el2));
> >> + DEFINE(VCPU_CPTR_EL2, offsetof(struct kvm_vcpu, arch.cptr_el2));
> >> DEFINE(VCPU_IRQ_LINES, offsetof(struct kvm_vcpu, arch.irq_lines));
> >> DEFINE(VCPU_HOST_CONTEXT, offsetof(struct kvm_vcpu, arch.host_cpu_context));
> >> DEFINE(VCPU_HOST_DEBUG_STATE, offsetof(struct kvm_vcpu, arch.host_debug_state));
> >> diff --git a/arch/arm64/kvm/Makefile b/arch/arm64/kvm/Makefile
> >> index 1949fe5..262b9a5 100644
> >> --- a/arch/arm64/kvm/Makefile
> >> +++ b/arch/arm64/kvm/Makefile
> >> @@ -17,7 +17,8 @@ kvm-$(CONFIG_KVM_ARM_HOST) += $(ARM)/psci.o $(ARM)/perf.o
> >>
> >> kvm-$(CONFIG_KVM_ARM_HOST) += emulate.o inject_fault.o regmap.o
> >> kvm-$(CONFIG_KVM_ARM_HOST) += hyp.o hyp-init.o handle_exit.o
> >> -kvm-$(CONFIG_KVM_ARM_HOST) += guest.o debug.o reset.o sys_regs.o sys_regs_generic_v8.o
> >> +kvm-$(CONFIG_KVM_ARM_HOST) += guest.o debug.o reset.o sys_regs.o
> >> +kvm-$(CONFIG_KVM_ARM_HOST) += sys_regs_generic_v8.o fpsimd_switch.o
> >>
> >> kvm-$(CONFIG_KVM_ARM_HOST) += $(KVM)/arm/vgic.o
> >> kvm-$(CONFIG_KVM_ARM_HOST) += $(KVM)/arm/vgic-v2.o
> >> diff --git a/arch/arm64/kvm/fpsimd_switch.S b/arch/arm64/kvm/fpsimd_switch.S
> >> new file mode 100644
> >> index 0000000..5295512
> >> --- /dev/null
> >> +++ b/arch/arm64/kvm/fpsimd_switch.S
> >> @@ -0,0 +1,38 @@
> >> +/*
> >> + * Copyright (C) 2012,2013 - ARM Ltd
> >> + * Author: Marc Zyngier <marc.zyngier at arm.com>
> >> + *
> >
> > Is this copied code or new code?
>
> It's mostly refactored copied code.
Then it's probably fine to keep the original copyright.
> >
> >> + * 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.
> >> + *
> >> + * 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, see <http://www.gnu.org/licenses/>.
> >> + */
> >> +
> >> +#include <linux/linkage.h>
> >> +
> >> +#include "hyp_head.S"
> >> +
> >> + .text
> >> +/**
> >> + * void kvm_restore_host_vfp_state(struct vcpu *vcpu) -
> >> + * This function saves the guest, restores host, called from host.
> >> + */
> >> +ENTRY(kvm_restore_host_vfp_state)
> >> + push xzr, lr
> >> +
> >> + add x2, x0, #VCPU_CONTEXT
> >> + bl __save_fpsimd
> >> +
> >> + ldr x2, [x0, #VCPU_HOST_CONTEXT]
> >> + bl __restore_fpsimd
> >> +
> >> + pop xzr, lr
> >> + ret
> >> +ENDPROC(kvm_restore_host_vfp_state)
> >> diff --git a/arch/arm64/kvm/hyp.S b/arch/arm64/kvm/hyp.S
> >> index e583613..b8b1afb 100644
> >> --- a/arch/arm64/kvm/hyp.S
> >> +++ b/arch/arm64/kvm/hyp.S
> >> @@ -17,23 +17,7 @@
> >>
> >> #include <linux/linkage.h>
> >>
> >> -#include <asm/alternative.h>
> >> -#include <asm/asm-offsets.h>
> >> -#include <asm/assembler.h>
> >> -#include <asm/cpufeature.h>
> >> -#include <asm/debug-monitors.h>
> >> -#include <asm/esr.h>
> >> -#include <asm/fpsimdmacros.h>
> >> -#include <asm/kvm.h>
> >> -#include <asm/kvm_arm.h>
> >> -#include <asm/kvm_asm.h>
> >> -#include <asm/kvm_mmu.h>
> >> -#include <asm/memory.h>
> >> -
> >> -#define CPU_GP_REG_OFFSET(x) (CPU_GP_REGS + x)
> >> -#define CPU_XREG_OFFSET(x) CPU_GP_REG_OFFSET(CPU_USER_PT_REGS + 8*x)
> >> -#define CPU_SPSR_OFFSET(x) CPU_GP_REG_OFFSET(CPU_SPSR + 8*x)
> >> -#define CPU_SYSREG_OFFSET(x) (CPU_SYSREGS + 8*x)
> >> +#include "hyp_head.S"
> >>
> >> .text
> >> .pushsection .hyp.text, "ax"
> >> @@ -104,20 +88,6 @@
> >> restore_common_regs
> >> .endm
> >>
> >> -.macro save_fpsimd
> >> - // x2: cpu context address
> >> - // x3, x4: tmp regs
> >> - add x3, x2, #CPU_GP_REG_OFFSET(CPU_FP_REGS)
> >> - fpsimd_save x3, 4
> >> -.endm
> >> -
> >> -.macro restore_fpsimd
> >> - // x2: cpu context address
> >> - // x3, x4: tmp regs
> >> - add x3, x2, #CPU_GP_REG_OFFSET(CPU_FP_REGS)
> >> - fpsimd_restore x3, 4
> >> -.endm
> >> -
> >> .macro save_guest_regs
> >> // x0 is the vcpu address
> >> // x1 is the return code, do not corrupt!
> >> @@ -385,14 +355,6 @@
> >> tbz \tmp, #KVM_ARM64_DEBUG_DIRTY_SHIFT, \target
> >> .endm
> >>
> >> -/*
> >> - * Branch to target if CPTR_EL2.TFP bit is set (VFP/SIMD trapping enabled)
> >> - */
> >> -.macro skip_fpsimd_state tmp, target
> >> - mrs \tmp, cptr_el2
> >> - tbnz \tmp, #CPTR_EL2_TFP_SHIFT, \target
> >> -.endm
> >> -
> >> .macro compute_debug_state target
> >> // Compute debug state: If any of KDE, MDE or KVM_ARM64_DEBUG_DIRTY
> >> // is set, we do a full save/restore cycle and disable trapping.
> >> @@ -433,10 +395,6 @@
> >> mrs x5, ifsr32_el2
> >> stp x4, x5, [x3]
> >>
> >> - skip_fpsimd_state x8, 2f
> >> - mrs x6, fpexc32_el2
> >> - str x6, [x3, #16]
> >> -2:
> >> skip_debug_state x8, 1f
> >> mrs x7, dbgvcr32_el2
> >> str x7, [x3, #24]
> >> @@ -467,22 +425,9 @@
> >>
> >> .macro activate_traps
> >> ldr x2, [x0, #VCPU_HCR_EL2]
> >> -
> >> - /*
> >> - * We are about to set CPTR_EL2.TFP to trap all floating point
> >> - * register accesses to EL2, however, the ARM ARM clearly states that
> >> - * traps are only taken to EL2 if the operation would not otherwise
> >> - * trap to EL1. Therefore, always make sure that for 32-bit guests,
> >> - * we set FPEXC.EN to prevent traps to EL1, when setting the TFP bit.
> >> - */
> >> - tbnz x2, #HCR_RW_SHIFT, 99f // open code skip_32bit_state
> >> - mov x3, #(1 << 30)
> >> - msr fpexc32_el2, x3
> >> - isb
> >> -99:
> >> msr hcr_el2, x2
> >> - mov x2, #CPTR_EL2_TTA
> >> - orr x2, x2, #CPTR_EL2_TFP
> >> +
> >> + ldr w2, [x0, VCPU_CPTR_EL2]
> >> msr cptr_el2, x2
> >>
> >> mov x2, #(1 << 15) // Trap CP15 Cr=15
> >> @@ -668,15 +613,15 @@ __restore_debug:
> >>
> >> ret
> >>
> >> -__save_fpsimd:
> >> - skip_fpsimd_state x3, 1f
> >> +ENTRY(__save_fpsimd)
> >> save_fpsimd
> >> -1: ret
> >> + ret
> >> +ENDPROC(__save_fpsimd)
> >>
> >> -__restore_fpsimd:
> >> - skip_fpsimd_state x3, 1f
> >> +ENTRY(__restore_fpsimd)
> >> restore_fpsimd
> >> -1: ret
> >> + ret
> >> +ENDPROC(__restore_fpsimd)
> >>
> >> switch_to_guest_fpsimd:
> >> push x4, lr
> >> @@ -763,7 +708,6 @@ __kvm_vcpu_return:
> >> add x2, x0, #VCPU_CONTEXT
> >>
> >> save_guest_regs
> >> - bl __save_fpsimd
> >> bl __save_sysregs
> >>
> >> skip_debug_state x3, 1f
> >> @@ -784,8 +728,10 @@ __kvm_vcpu_return:
> >> kern_hyp_va x2
> >>
> >> bl __restore_sysregs
> >> - bl __restore_fpsimd
> >> - /* Clear FPSIMD and Trace trapping */
> >> +
> >> + /* Save CPTR_EL2 between exits and clear FPSIMD and Trace trapping */
> >> + mrs x3, cptr_el2
> >> + str w3, [x0, VCPU_CPTR_EL2]
> >> msr cptr_el2, xzr
> >>
> >> skip_debug_state x3, 1f
> >> @@ -863,6 +809,34 @@ ENTRY(__kvm_flush_vm_context)
> >> ret
> >> ENDPROC(__kvm_flush_vm_context)
> >>
> >> +/**
> >> + * void __kvm_enable_fpexc32(void) -
> >> + * We may be entering the guest and set CPTR_EL2.TFP to trap all floating
> >> + * point register accesses to EL2, however, the ARM manual clearly states
> >> + * that traps are only taken to EL2 if the operation would not otherwise
> >> + * trap to EL1. Therefore, always make sure that for 32-bit guests,
> >> + * we set FPEXC.EN to prevent traps to EL1, when setting the TFP bit.
> >> + */
> >> +ENTRY(__kvm_vcpu_enable_fpexc32)
> >> + mov x3, #(1 << 30)
> >> + msr fpexc32_el2, x3
> >> + isb
> >
> > this is only called via a hypercall so do you really need the ISB?
>
> Same comment as in 2nd patch for the isb.
>
Unless you can argue that something needs to take effect before
something else, where there's no other implicit barrier, you don't need
the ISB.
> >
> >> + ret
> >> +ENDPROC(__kvm_vcpu_enable_fpexc32)
> >> +
> >> +/**
> >> + * void __kvm_save_fpexc32(void) -
> >> + * This function restores guest FPEXC to its vcpu context, we call this
> >> + * function from vcpu_put.
> >> + */
> >> +ENTRY(__kvm_vcpu_save_fpexc32)
> >> + kern_hyp_va x0
> >> + add x2, x0, #VCPU_CONTEXT
> >> + mrs x1, fpexc32_el2
> >> + str x1, [x2, #CPU_SYSREG_OFFSET(FPEXC32_EL2)]
> >> + ret
> >> +ENDPROC(__kvm_vcpu_save_fpexc32)
> >> +
> >> __kvm_hyp_panic:
> >> // Guess the context by looking at VTTBR:
> >> // If zero, then we're already a host.
> >> diff --git a/arch/arm64/kvm/hyp_head.S b/arch/arm64/kvm/hyp_head.S
> >> new file mode 100644
> >> index 0000000..bb32824
> >> --- /dev/null
> >> +++ b/arch/arm64/kvm/hyp_head.S
> >> @@ -0,0 +1,48 @@
> >> +/*
> >> + * Copyright (C) 2012,2013 - ARM Ltd
> >> + * Author: Marc Zyngier <marc.zyngier at arm.com>
> >> + *
> >> + * 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.
> >> + *
> >> + * 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, see <http://www.gnu.org/licenses/>.
> >> + */
> >> +
> >> +#include <asm/alternative.h>
> >> +#include <asm/asm-offsets.h>
> >> +#include <asm/assembler.h>
> >> +#include <asm/cpufeature.h>
> >> +#include <asm/debug-monitors.h>
> >> +#include <asm/esr.h>
> >> +#include <asm/fpsimdmacros.h>
> >> +#include <asm/kvm.h>
> >> +#include <asm/kvm_arm.h>
> >> +#include <asm/kvm_asm.h>
> >> +#include <asm/kvm_mmu.h>
> >> +#include <asm/memory.h>
> >> +
> >> +#define CPU_GP_REG_OFFSET(x) (CPU_GP_REGS + x)
> >> +#define CPU_XREG_OFFSET(x) CPU_GP_REG_OFFSET(CPU_USER_PT_REGS + 8*x)
> >> +#define CPU_SPSR_OFFSET(x) CPU_GP_REG_OFFSET(CPU_SPSR + 8*x)
> >> +#define CPU_SYSREG_OFFSET(x) (CPU_SYSREGS + 8*x)
> >> +
> >> +.macro save_fpsimd
> >> + // x2: cpu context address
> >> + // x3, x4: tmp regs
> >> + add x3, x2, #CPU_GP_REG_OFFSET(CPU_FP_REGS)
> >> + fpsimd_save x3, 4
> >> +.endm
> >> +
> >> +.macro restore_fpsimd
> >> + // x2: cpu context address
> >> + // x3, x4: tmp regs
> >> + add x3, x2, #CPU_GP_REG_OFFSET(CPU_FP_REGS)
> >> + fpsimd_restore x3, 4
> >> +.endm
> >> --
> >> 1.9.1
> >>
> >
> > I'm not going to review the details of this, since we have to rebase it
> > on the world-switch in C, sorry.
> That fine.
> >
> > The good news is that it should be much simpler to write in C-code.
> >
> > Let me know if you don't have the bandwidth to rebase this, in that case
> > I'll be happy to help.
>
> Let me see where I'm at by the end of Monday, if there is a rush to get it into
> next release by all means.
>
Sounds good - I prefer having you do it ;)
-Christoffer
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