[register]-ARMV8系统中通用寄存器和系统寄存器的介绍和总结

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• 【精选】ARMv8/ARMv9架构入门到精通-[目录]👈👈👈

说明：
在默认情况下，本文讲述的都是ARMV8-aarch64架构，linux kernel 64位

文章目录

• 通用寄存器

• 1、X0-X31
• 2、特殊寄存器：
• 3、aarch32 register

• System registers

• 1、Special-purpose registers
• 2、Base system registers
• 3、VMSA-specific registers
• 4、Address translation system instructions
• 5、TLB maintenance system instructions
• 6、Cache maintenance system instructions
• 7、Generic timer registers
• 8、RAS registers
• 9、Debug registers
• 10、Performance monitors registers
• 11、ID registers
• 12、Prediction restriction System instructions
• 13、必备寄存器总结

通用寄存器

1、X0-X31

ARMv8有31个通用寄存器X0-X30, 还有SP、PC、XZR等寄存器
下面详细介绍写这些通用寄存器(general-purpose registers)：

• X0-X7 用于参数传递
• X9-X15 在子函数中使用这些寄存器时，直接使用即可, 无需save/restore. 在汇编代码中x9-x15出现的频率极低
  在子函数中使用这些寄存器时，直接使用即可, 无需save/restore. 在汇编代码中x9-x15出现的频率极低
• X19-X29 在callee子函数中使用这些寄存器时，需要先save这些寄存器，在退出子函数时再resotre
  在callee子函数中使用这些寄存器时，需要先save这些寄存器，在退出子函数时再resotre
• X8, X16-X18, X29, X30 这些都是特殊用途的寄存器
  – X8： 用于返回结果
  – X16、X17 ：进程内临时寄存器
  – X18 ：resrved for ABI
  – X29 ：FP（frame pointer register）
  – X30 ：LR

2、特殊寄存器：

部分寄存器还可以当作32位的使用

sp(Stack pointer)

EL1t: t表示选择SP_EL0

EL1h:h表示选择SP_ELx(x>0)

PC(Program Counter)
在armv7上PC是一个通用寄存器R15，在armv8上PC不在是一个寄存器，它不能直接被修改。必需使用一些隐式的指令来改变，如PC-relative load

SPSR

• N Negative result (N flag).
• Z Zero result (Z) flag.
• C Carry out (C flag).
• V Overflow (V flag).
• SS Software Step. Indicates whether software step was enabled when an exception was taken.
• IL Illegal Execution State bit. Shows the value of PSTATE.IL immediately before the exception was taken.
• D Debug mask：watchpoint,breakpoint
• A SError (System Error) mask bit.
• I IRQ mask bit.
• F FIQ mask bit.
• M[4] Execution state that the exception was taken from. A value of 0 indicates AArch64.
• M[3:0] Mode or Exception level that an exception was taken from

PSTATE (Processor state)

在aarch64中，调用ERET从一个异常返回时，会将SPSR_ELn恢复到PSTATE中，将恢复：ALU的flag、执行状态(aarch64 or aarch32)、异常级别、processor branches

PSTATE.{N, Z, C, V}可以在EL0中被修改，其余的bit只能在ELx(x>0)中修改

3、aarch32 register

执行状态的切换(aarch64/aarch32)

当从aarch32切换到aarch64时：
1、一些64位寄存器的高32bit，曾经被map到aarch32中的一些寄存器。这些高32bit是unknown状态
2、一些64位寄存器的高32bit，在aarch32中没有使用，这些高32bit还是以前的值;
3、如果是跳转到EL3，EL2是aarch32，那么ELR_EL2的高32bit是unknown
4、以下寄存器，不会再aarch32中使用到
— SP_EL0.
— SP_EL1.
— SP_EL2.
— ELR_EL1

aarch64到aarch32的map:

PSTATE at AArch32

System registers

AArch64 registers：
• Special-purpose registers.
• Base system registers
• VMSA-specific registers
• ID registers on page
• Performance monitors registers
• Debug registers
• RAS registers
• Generic timer registers
• Cache maintenance system instructions
• Address translation system instructions
• TLB maintenance system instructions
• Prediction restriction System instructions

1、Special-purpose registers

3个ELR， 4个SP， 8个SPSR

2、Base system registers

118个base system registers

3、VMSA-specific registers

24个VMSA寄存器

4、Address translation system instructions

14个地址翻译指令

AT S12E0R
AT S12E0W
AT S12E1R
AT S12E1W
AT S1E0R
AT S1E0W
AT S1E1R
AT S1E1RP
AT S1E1W
AT S1E1WP
AT S1E2R
AT S1E2W
AT S1E3R
AT S1E3W

5、TLB maintenance system instructions

78个TLB一致性指令

TLBI ALLE1
TLBI ALLE1IS
TLBI ALLE1OS
TLBI ALLE2
TLBI ALLE2IS
TLBI ALLE2OS
TLBI ALLE3
TLBI ALLE3IS
TLBI ALLE3OS
TLBI ASIDE1
TLBI ASIDE1IS
TLBI ASIDE1OS
TLBI IPAS2E1
TLBI IPAS2E1IS
TLBI IPAS2E1OS
TLBI IPAS2LE1
TLBI IPAS2LE1IS
TLBI IPAS2LE1OS
TLBI RIPAS2E1
TLBI RIPAS2E1IS
TLBI RIPAS2E1OS
TLBI RIPAS2LE1
TLBI RIPAS2LE1IS
TLBI RIPAS2LE1OS
TLBI RVAAE1
TLBI RVAAE1IS
TLBI RVAAE1OS
TLBI RVAALE1
TLBI RVAALE1IS
TLBI RVAALE1OS
TLBI RVAE1
TLBI RVAE1IS
TLBI RVAE1OS
TLBI RVAE2
TLBI RVAE2IS
TLBI RVAE2OS
TLBI RVAE3
TLBI RVAE3IS
TLBI RVAE3OS
TLBI RVALE1
TLBI RVALE1IS
TLBI RVALE1OS
TLBI RVALE2
TLBI RVALE2IS
TLBI RVALE2OS
TLBI RVALE3
TLBI RVALE3IS
TLBI RVALE3OS
TLBI VAAE1
TLBI VAAE1IS
TLBI VAAE1OS
TLBI VAALE1
TLBI VAALE1IS
TLBI VAALE1OS
TLBI VAE1
TLBI VAE1IS
TLBI VAE1OS
TLBI VAE2
TLBI VAE2IS
TLBI VAE2OS
TLBI VAE3
TLBI VAE3IS
TLBI VAE3OS
TLBI VALE1
TLBI VALE1IS
TLBI VALE1OS
TLBI VALE2
TLBI VALE2IS
TLBI VALE2OS
TLBI VALE3
TLBI VALE3IS
TLBI VALE3OS
TLBI VMALLE1
TLBI VMALLE1IS
TLBI VMALLE1OS
TLBI VMALLS12E1
TLBI VMALLS12E1IS
TLBI VMALLS12E1OS

6、Cache maintenance system instructions

31个cache一致性指令

DC CGDSW
DC CGDVAC
DC CGDVADP
DC CGDVAP
DC CGSW
DC CGVAC
DC CGVADP
DC CGVAP
DC CIGDSW
DC CIGDVAC
DC CIGSW
DC CIGVAC
DC CISW
DC CIVAC
DC CSW
DC CVAC
DC CVADP
DC CVAP
DC CVAU
DC GVA
DC GZVA
DC IGDSW
DC IGDVAC
DC IGSW
DC IGVAC
DC ISW
DC IVAC
DC ZVA
IC IALLU
IC IALLUIS
IC IVAU

7、Generic timer registers

22个generic Timer寄存器

CNTFRQ_EL0
CNTHV_CTL_EL2
CNTHV_CVAL_EL2
CNTHV_TVAL_EL2
CNTHVS_CTL_EL2
CNTHVS_CVAL_EL2
CNTHVS_TVAL_EL2
CNTKCTL_EL1
CNTP_CTL_EL0
CNTP_CVAL_EL0
CNTP_TVAL_EL0
CNTPCT_EL0
CNTPCTSS_EL0
CNTPOFF_EL2
CNTPS_CTL_EL1
CNTPS_CVAL_EL1
CNTPS_TVAL_EL1
CNTV_CTL_EL0
CNTV_CVAL_EL0
CNTV_TVAL_EL0
CNTVCT_EL0
CNTVCTSS_EL0

8、RAS registers

16个RAS寄存器

DISR_EL1
ERRIDR_EL1
ERRSELR_EL1
ERXADDR_EL1
ERXCTLR_EL1
ERXFR_EL1
ERXMISC0_EL1
ERXMISC1_EL1
ERXMISC2_EL1
ERXMISC3_EL1
ERXPFGCDN_EL1
ERXPFGCTL_EL1
ERXPFGF_EL1
ERXSTATUS_EL1
VDISR_EL2
VSESR_EL2

9、Debug registers

23个debug寄存器

DBGAUTHSTATUS_EL1
DBGBCR_EL1
DBGBVR_EL1
DBGCLAIMCLR_EL1
DBGCLAIMSET_EL1
DBGDTR_EL0
DBGDTRRX_EL0
DBGDTRTX_EL0
DBGPRCR_EL1
DBGVCR32_EL2
DBGWCR_EL1
DBGWVR_EL1
DLR_EL0
DSPSR_EL0
MDCCINT_EL1
MDCCSR_EL0
MDRAR_EL1
MDSCR_EL1
OSDLR_EL1
OSDTRRX_EL1
OSDTRTX_EL1
OSECCR_EL1
OSLAR_EL1

10、Performance monitors registers

19个performance寄存器

PMCCFILTR_EL0
PMCCNTR_EL0
PMCEID0_EL0
PMCEID1_EL0
PMCNTENCLR_EL0
PMCNTENSET_EL0
PMCR_EL0
PMEVCNTR_EL0
PMEVTYPER_EL0
PMINTENCLR_EL1
PMINTENSET_EL1
PMMIR_EL1
PMOVSCLR_EL0
PMOVSSET_EL0
PMSELR_EL0
PMSWINC_EL0
PMUSERENR_EL0
PMXEVCNTR_EL0
PMXEVTYPER_EL0

11、ID registers

40个ID寄存器

CCSIDR2_EL1
CCSIDR_EL1
CLIDR_EL1
CSSELR_EL1
CTR_EL0
DCZID_EL0
GMID_EL1
ID_AA64AFR0_EL1
ID_AA64AFR1_EL1
ID_AA64DFR0_EL1
ID_AA64DFR1_EL1
ID_AA64ISAR0_EL1
ID_AA64ISAR1_EL1
ID_AA64MMFR0_EL1
ID_AA64MMFR1_EL1
ID_AA64MMFR2_EL1
ID_AA64PFR0_EL1
ID_AA64PFR1_EL1
ID_AFR0_EL1 ID_AFR0_EL1
ID_DFR0_EL1 ID_DFR0_EL1
ID_DFR1_EL1 ID_DFR1_EL1
ID_ISAR0_EL1
ID_ISAR1_EL1
ID_ISAR2_EL1
ID_ISAR3_EL1
ID_ISAR4_EL1
ID_ISAR5_EL1
ID_ISAR6_EL1
ID_MMFR0_EL1
ID_MMFR1_EL1
ID_MMFR2_EL1
ID_MMFR3_EL1
ID_MMFR4_EL1
ID_MMFR5_EL1
ID_PFR0_EL1
ID_PFR1_EL1
ID_PFR2_EL1
MIDR_EL1
MPIDR_EL1
REVIDR_EL1

12、Prediction restriction System instructions

3个预测限制寄存器

13、必备寄存器总结

PSTATE：程序状态寄存器


SP_ELx(x>0)：在EL1/EL2/EL3 level中，如果spsel=0，则使用SP_ELx(x>0)
SP_EL0 ：在所有level中，如果spsel=1, 则使用SP_EL0


SPSR ：save program status register 备份的程序状态寄存器


ELR_ELx(x>0)：异常链接寄存器，记录着异常时程序的返回地址


ESR_ELx(x>0) ：同步异常, 异常特征寄存器
FAR_ELx(x>0)： 同步异常, 异常时的错误地址


VBAR_ELx(x>0)： 向量表基地址寄存器


TTBRn_ELx(n=1,2、x>0)： 地址翻译基地址寄存器
MAIR_ELx(x>0) ：内存属性寄存器


PAR_EL1： 物理地址寄存器, 当使用指令操作MMU进行VA到PA的转换时，物理地址由PAR_EL1输出.


SCR_EL3 ：安全配置寄存器
SCTLR_ELx(x>0）： 系统控制寄存器
TCR_ELx(x>0)： 地址翻译控制寄存器

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