[PATCH 4/6] arm64/kvm: use {read,write}_sysreg()
Christoffer Dall
christoffer.dall at linaro.org
Thu Sep 8 06:34:46 PDT 2016
On Thu, Sep 08, 2016 at 01:55:37PM +0100, Mark Rutland wrote:
> A while back we added {read,write}_sysreg accessors to handle accesses
> to system registers, without the usual boilerplate asm volatile,
> temporary variable, etc.
>
> This patch makes use of these in the arm64 KVM code to make the code
> shorter and clearer.
>
> At the same time, a comment style violation next to a system register
> access is fixed up in reset_pmcr, and comments describing whether
> operations are reads or writes are removed as this is now painfully
> obvious.
Acked-by: Christoffer Dall <christoffer.dall at linaro.org>
>
> Signed-off-by: Mark Rutland <mark.rutland at arm.com>
> Cc: Catalin Marinas <catalin.marinas at arm.com>
> Cc: Christoffer Dall <christoffer.dall at linaro.org>
> Cc: Marc Zyngier <marc.zyngier at arm.com>
> Cc: Will Deacon <will.deacon at arm.com>
> ---
> arch/arm64/include/asm/virt.h | 6 ++----
> arch/arm64/kvm/sys_regs.c | 31 +++++++++++--------------------
> arch/arm64/kvm/sys_regs_generic_v8.c | 6 ++----
> 3 files changed, 15 insertions(+), 28 deletions(-)
>
> diff --git a/arch/arm64/include/asm/virt.h b/arch/arm64/include/asm/virt.h
> index 1788545..c5cc940 100644
> --- a/arch/arm64/include/asm/virt.h
> +++ b/arch/arm64/include/asm/virt.h
> @@ -45,6 +45,7 @@
> #ifndef __ASSEMBLY__
>
> #include <asm/ptrace.h>
> +#include <asm/sysreg.h>
>
> /*
> * __boot_cpu_mode records what mode CPUs were booted in.
> @@ -75,10 +76,7 @@ static inline bool is_hyp_mode_mismatched(void)
>
> static inline bool is_kernel_in_hyp_mode(void)
> {
> - u64 el;
> -
> - asm("mrs %0, CurrentEL" : "=r" (el));
> - return el == CurrentEL_EL2;
> + return read_sysreg(CurrentEL) == CurrentEL_EL2;
> }
>
> #ifdef CONFIG_ARM64_VHE
> diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
> index e51367d..f302fdb 100644
> --- a/arch/arm64/kvm/sys_regs.c
> +++ b/arch/arm64/kvm/sys_regs.c
> @@ -36,6 +36,7 @@
> #include <asm/kvm_host.h>
> #include <asm/kvm_mmu.h>
> #include <asm/perf_event.h>
> +#include <asm/sysreg.h>
>
> #include <trace/events/kvm.h>
>
> @@ -67,11 +68,9 @@ static u32 get_ccsidr(u32 csselr)
>
> /* Make sure noone else changes CSSELR during this! */
> local_irq_disable();
> - /* Put value into CSSELR */
> - asm volatile("msr csselr_el1, %x0" : : "r" (csselr));
> + write_sysreg(csselr, csselr_el1);
> isb();
> - /* Read result out of CCSIDR */
> - asm volatile("mrs %0, ccsidr_el1" : "=r" (ccsidr));
> + ccsidr = read_sysreg(ccsidr_el1);
> local_irq_enable();
>
> return ccsidr;
> @@ -174,9 +173,7 @@ static bool trap_dbgauthstatus_el1(struct kvm_vcpu *vcpu,
> if (p->is_write) {
> return ignore_write(vcpu, p);
> } else {
> - u32 val;
> - asm volatile("mrs %0, dbgauthstatus_el1" : "=r" (val));
> - p->regval = val;
> + p->regval = read_sysreg(dbgauthstatus_el1);
> return true;
> }
> }
> @@ -429,10 +426,7 @@ static void reset_wcr(struct kvm_vcpu *vcpu,
>
> static void reset_amair_el1(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
> {
> - u64 amair;
> -
> - asm volatile("mrs %0, amair_el1\n" : "=r" (amair));
> - vcpu_sys_reg(vcpu, AMAIR_EL1) = amair;
> + vcpu_sys_reg(vcpu, AMAIR_EL1) = read_sysreg(amair_el1);
> }
>
> static void reset_mpidr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
> @@ -456,8 +450,9 @@ static void reset_pmcr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
> {
> u64 pmcr, val;
>
> - asm volatile("mrs %0, pmcr_el0\n" : "=r" (pmcr));
> - /* Writable bits of PMCR_EL0 (ARMV8_PMU_PMCR_MASK) is reset to UNKNOWN
> + pmcr = read_sysreg(pmcr_el0);
> + /*
> + * Writable bits of PMCR_EL0 (ARMV8_PMU_PMCR_MASK) are reset to UNKNOWN
> * except PMCR.E resetting to zero.
> */
> val = ((pmcr & ~ARMV8_PMU_PMCR_MASK)
> @@ -557,9 +552,9 @@ static bool access_pmceid(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
> return false;
>
> if (!(p->Op2 & 1))
> - asm volatile("mrs %0, pmceid0_el0\n" : "=r" (pmceid));
> + pmceid = read_sysreg(pmceid0_el0);
> else
> - asm volatile("mrs %0, pmceid1_el0\n" : "=r" (pmceid));
> + pmceid = read_sysreg(pmceid1_el0);
>
> p->regval = pmceid;
>
> @@ -1833,11 +1828,7 @@ static const struct sys_reg_desc *index_to_sys_reg_desc(struct kvm_vcpu *vcpu,
> static void get_##reg(struct kvm_vcpu *v, \
> const struct sys_reg_desc *r) \
> { \
> - u64 val; \
> - \
> - asm volatile("mrs %0, " __stringify(reg) "\n" \
> - : "=r" (val)); \
> - ((struct sys_reg_desc *)r)->val = val; \
> + ((struct sys_reg_desc *)r)->val = read_sysreg(reg); \
> }
>
> FUNCTION_INVARIANT(midr_el1)
> diff --git a/arch/arm64/kvm/sys_regs_generic_v8.c b/arch/arm64/kvm/sys_regs_generic_v8.c
> index ed90578..46af718 100644
> --- a/arch/arm64/kvm/sys_regs_generic_v8.c
> +++ b/arch/arm64/kvm/sys_regs_generic_v8.c
> @@ -26,6 +26,7 @@
> #include <asm/kvm_host.h>
> #include <asm/kvm_emulate.h>
> #include <asm/kvm_coproc.h>
> +#include <asm/sysreg.h>
> #include <linux/init.h>
>
> #include "sys_regs.h"
> @@ -43,10 +44,7 @@ static bool access_actlr(struct kvm_vcpu *vcpu,
>
> static void reset_actlr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
> {
> - u64 actlr;
> -
> - asm volatile("mrs %0, actlr_el1\n" : "=r" (actlr));
> - vcpu_sys_reg(vcpu, ACTLR_EL1) = actlr;
> + vcpu_sys_reg(vcpu, ACTLR_EL1) = read_sysreg(actlr_el1);
> }
>
> /*
> --
> 1.9.1
>
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