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Diffstat (limited to 'target/arm/cpregs.h')
| -rw-r--r-- | target/arm/cpregs.h | 413 |
1 files changed, 413 insertions, 0 deletions
diff --git a/target/arm/cpregs.h b/target/arm/cpregs.h new file mode 100644 index 0000000000..8064c0763e --- /dev/null +++ b/target/arm/cpregs.h @@ -0,0 +1,413 @@ +/* + * QEMU ARM CP Register access and descriptions + * + * Copyright (c) 2022 Linaro Ltd + * + * 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, see + * <http://www.gnu.org/licenses/gpl-2.0.html> + */ + +#ifndef TARGET_ARM_CPREGS_H +#define TARGET_ARM_CPREGS_H + +/* + * ARMCPRegInfo type field bits. If the SPECIAL bit is set this is a + * special-behaviour cp reg and bits [11..8] indicate what behaviour + * it has. Otherwise it is a simple cp reg, where CONST indicates that + * TCG can assume the value to be constant (ie load at translate time) + * and 64BIT indicates a 64 bit wide coprocessor register. SUPPRESS_TB_END + * indicates that the TB should not be ended after a write to this register + * (the default is that the TB ends after cp writes). OVERRIDE permits + * a register definition to override a previous definition for the + * same (cp, is64, crn, crm, opc1, opc2) tuple: either the new or the + * old must have the OVERRIDE bit set. + * ALIAS indicates that this register is an alias view of some underlying + * state which is also visible via another register, and that the other + * register is handling migration and reset; registers marked ALIAS will not be + * migrated but may have their state set by syncing of register state from KVM. + * NO_RAW indicates that this register has no underlying state and does not + * support raw access for state saving/loading; it will not be used for either + * migration or KVM state synchronization. (Typically this is for "registers" + * which are actually used as instructions for cache maintenance and so on.) + * IO indicates that this register does I/O and therefore its accesses + * need to be marked with gen_io_start() and also end the TB. In particular, + * registers which implement clocks or timers require this. + * RAISES_EXC is for when the read or write hook might raise an exception; + * the generated code will synchronize the CPU state before calling the hook + * so that it is safe for the hook to call raise_exception(). + * NEWEL is for writes to registers that might change the exception + * level - typically on older ARM chips. For those cases we need to + * re-read the new el when recomputing the translation flags. + */ +#define ARM_CP_SPECIAL 0x0001 +#define ARM_CP_CONST 0x0002 +#define ARM_CP_64BIT 0x0004 +#define ARM_CP_SUPPRESS_TB_END 0x0008 +#define ARM_CP_OVERRIDE 0x0010 +#define ARM_CP_ALIAS 0x0020 +#define ARM_CP_IO 0x0040 +#define ARM_CP_NO_RAW 0x0080 +#define ARM_CP_NOP (ARM_CP_SPECIAL | 0x0100) +#define ARM_CP_WFI (ARM_CP_SPECIAL | 0x0200) +#define ARM_CP_NZCV (ARM_CP_SPECIAL | 0x0300) +#define ARM_CP_CURRENTEL (ARM_CP_SPECIAL | 0x0400) +#define ARM_CP_DC_ZVA (ARM_CP_SPECIAL | 0x0500) +#define ARM_CP_DC_GVA (ARM_CP_SPECIAL | 0x0600) +#define ARM_CP_DC_GZVA (ARM_CP_SPECIAL | 0x0700) +#define ARM_LAST_SPECIAL ARM_CP_DC_GZVA +#define ARM_CP_FPU 0x1000 +#define ARM_CP_SVE 0x2000 +#define ARM_CP_NO_GDB 0x4000 +#define ARM_CP_RAISES_EXC 0x8000 +#define ARM_CP_NEWEL 0x10000 +/* Used only as a terminator for ARMCPRegInfo lists */ +#define ARM_CP_SENTINEL 0xfffff +/* Mask of only the flag bits in a type field */ +#define ARM_CP_FLAG_MASK 0x1f0ff + +/* + * Valid values for ARMCPRegInfo state field, indicating which of + * the AArch32 and AArch64 execution states this register is visible in. + * If the reginfo doesn't explicitly specify then it is AArch32 only. + * If the reginfo is declared to be visible in both states then a second + * reginfo is synthesised for the AArch32 view of the AArch64 register, + * such that the AArch32 view is the lower 32 bits of the AArch64 one. + * Note that we rely on the values of these enums as we iterate through + * the various states in some places. + */ +enum { + ARM_CP_STATE_AA32 = 0, + ARM_CP_STATE_AA64 = 1, + ARM_CP_STATE_BOTH = 2, +}; + +/* + * ARM CP register secure state flags. These flags identify security state + * attributes for a given CP register entry. + * The existence of both or neither secure and non-secure flags indicates that + * the register has both a secure and non-secure hash entry. A single one of + * these flags causes the register to only be hashed for the specified + * security state. + * Although definitions may have any combination of the S/NS bits, each + * registered entry will only have one to identify whether the entry is secure + * or non-secure. + */ +enum { + ARM_CP_SECSTATE_S = (1 << 0), /* bit[0]: Secure state register */ + ARM_CP_SECSTATE_NS = (1 << 1), /* bit[1]: Non-secure state register */ +}; + +/* + * Return true if cptype is a valid type field. This is used to try to + * catch errors where the sentinel has been accidentally left off the end + * of a list of registers. + */ +static inline bool cptype_valid(int cptype) +{ + return ((cptype & ~ARM_CP_FLAG_MASK) == 0) + || ((cptype & ARM_CP_SPECIAL) && + ((cptype & ~ARM_CP_FLAG_MASK) <= ARM_LAST_SPECIAL)); +} + +/* + * Access rights: + * We define bits for Read and Write access for what rev C of the v7-AR ARM ARM + * defines as PL0 (user), PL1 (fiq/irq/svc/abt/und/sys, ie privileged), and + * PL2 (hyp). The other level which has Read and Write bits is Secure PL1 + * (ie any of the privileged modes in Secure state, or Monitor mode). + * If a register is accessible in one privilege level it's always accessible + * in higher privilege levels too. Since "Secure PL1" also follows this rule + * (ie anything visible in PL2 is visible in S-PL1, some things are only + * visible in S-PL1) but "Secure PL1" is a bit of a mouthful, we bend the + * terminology a little and call this PL3. + * In AArch64 things are somewhat simpler as the PLx bits line up exactly + * with the ELx exception levels. + * + * If access permissions for a register are more complex than can be + * described with these bits, then use a laxer set of restrictions, and + * do the more restrictive/complex check inside a helper function. + */ +#define PL3_R 0x80 +#define PL3_W 0x40 +#define PL2_R (0x20 | PL3_R) +#define PL2_W (0x10 | PL3_W) +#define PL1_R (0x08 | PL2_R) +#define PL1_W (0x04 | PL2_W) +#define PL0_R (0x02 | PL1_R) +#define PL0_W (0x01 | PL1_W) + +/* + * For user-mode some registers are accessible to EL0 via a kernel + * trap-and-emulate ABI. In this case we define the read permissions + * as actually being PL0_R. However some bits of any given register + * may still be masked. + */ +#ifdef CONFIG_USER_ONLY +#define PL0U_R PL0_R +#else +#define PL0U_R PL1_R +#endif + +#define PL3_RW (PL3_R | PL3_W) +#define PL2_RW (PL2_R | PL2_W) +#define PL1_RW (PL1_R | PL1_W) +#define PL0_RW (PL0_R | PL0_W) + +typedef enum CPAccessResult { + /* Access is permitted */ + CP_ACCESS_OK = 0, + /* + * Access fails due to a configurable trap or enable which would + * result in a categorized exception syndrome giving information about + * the failing instruction (ie syndrome category 0x3, 0x4, 0x5, 0x6, + * 0xc or 0x18). The exception is taken to the usual target EL (EL1 or + * PL1 if in EL0, otherwise to the current EL). + */ + CP_ACCESS_TRAP = 1, + /* + * Access fails and results in an exception syndrome 0x0 ("uncategorized"). + * Note that this is not a catch-all case -- the set of cases which may + * result in this failure is specifically defined by the architecture. + */ + CP_ACCESS_TRAP_UNCATEGORIZED = 2, + /* As CP_ACCESS_TRAP, but for traps directly to EL2 or EL3 */ + CP_ACCESS_TRAP_EL2 = 3, + CP_ACCESS_TRAP_EL3 = 4, + /* As CP_ACCESS_UNCATEGORIZED, but for traps directly to EL2 or EL3 */ + CP_ACCESS_TRAP_UNCATEGORIZED_EL2 = 5, + CP_ACCESS_TRAP_UNCATEGORIZED_EL3 = 6, +} CPAccessResult; + +typedef struct ARMCPRegInfo ARMCPRegInfo; + +/* + * Access functions for coprocessor registers. These cannot fail and + * may not raise exceptions. + */ +typedef uint64_t CPReadFn(CPUARMState *env, const ARMCPRegInfo *opaque); +typedef void CPWriteFn(CPUARMState *env, const ARMCPRegInfo *opaque, + uint64_t value); +/* Access permission check functions for coprocessor registers. */ +typedef CPAccessResult CPAccessFn(CPUARMState *env, + const ARMCPRegInfo *opaque, + bool isread); +/* Hook function for register reset */ +typedef void CPResetFn(CPUARMState *env, const ARMCPRegInfo *opaque); + +#define CP_ANY 0xff + +/* Definition of an ARM coprocessor register */ +struct ARMCPRegInfo { + /* Name of register (useful mainly for debugging, need not be unique) */ + const char *name; + /* + * Location of register: coprocessor number and (crn,crm,opc1,opc2) + * tuple. Any of crm, opc1 and opc2 may be CP_ANY to indicate a + * 'wildcard' field -- any value of that field in the MRC/MCR insn + * will be decoded to this register. The register read and write + * callbacks will be passed an ARMCPRegInfo with the crn/crm/opc1/opc2 + * used by the program, so it is possible to register a wildcard and + * then behave differently on read/write if necessary. + * For 64 bit registers, only crm and opc1 are relevant; crn and opc2 + * must both be zero. + * For AArch64-visible registers, opc0 is also used. + * Since there are no "coprocessors" in AArch64, cp is purely used as a + * way to distinguish (for KVM's benefit) guest-visible system registers + * from demuxed ones provided to preserve the "no side effects on + * KVM register read/write from QEMU" semantics. cp==0x13 is guest + * visible (to match KVM's encoding); cp==0 will be converted to + * cp==0x13 when the ARMCPRegInfo is registered, for convenience. + */ + uint8_t cp; + uint8_t crn; + uint8_t crm; + uint8_t opc0; + uint8_t opc1; + uint8_t opc2; + /* Execution state in which this register is visible: ARM_CP_STATE_* */ + int state; + /* Register type: ARM_CP_* bits/values */ + int type; + /* Access rights: PL*_[RW] */ + int access; + /* Security state: ARM_CP_SECSTATE_* bits/values */ + int secure; + /* + * The opaque pointer passed to define_arm_cp_regs_with_opaque() when + * this register was defined: can be used to hand data through to the + * register read/write functions, since they are passed the ARMCPRegInfo*. + */ + void *opaque; + /* + * Value of this register, if it is ARM_CP_CONST. Otherwise, if + * fieldoffset is non-zero, the reset value of the register. + */ + uint64_t resetvalue; + /* + * Offset of the field in CPUARMState for this register. + * This is not needed if either: + * 1. type is ARM_CP_CONST or one of the ARM_CP_SPECIALs + * 2. both readfn and writefn are specified + */ + ptrdiff_t fieldoffset; /* offsetof(CPUARMState, field) */ + + /* + * Offsets of the secure and non-secure fields in CPUARMState for the + * register if it is banked. These fields are only used during the static + * registration of a register. During hashing the bank associated + * with a given security state is copied to fieldoffset which is used from + * there on out. + * + * It is expected that register definitions use either fieldoffset or + * bank_fieldoffsets in the definition but not both. It is also expected + * that both bank offsets are set when defining a banked register. This + * use indicates that a register is banked. + */ + ptrdiff_t bank_fieldoffsets[2]; + + /* + * Function for making any access checks for this register in addition to + * those specified by the 'access' permissions bits. If NULL, no extra + * checks required. The access check is performed at runtime, not at + * translate time. + */ + CPAccessFn *accessfn; + /* + * Function for handling reads of this register. If NULL, then reads + * will be done by loading from the offset into CPUARMState specified + * by fieldoffset. + */ + CPReadFn *readfn; + /* + * Function for handling writes of this register. If NULL, then writes + * will be done by writing to the offset into CPUARMState specified + * by fieldoffset. + */ + CPWriteFn *writefn; + /* + * Function for doing a "raw" read; used when we need to copy + * coprocessor state to the kernel for KVM or out for + * migration. This only needs to be provided if there is also a + * readfn and it has side effects (for instance clear-on-read bits). + */ + CPReadFn *raw_readfn; + /* + * Function for doing a "raw" write; used when we need to copy KVM + * kernel coprocessor state into userspace, or for inbound + * migration. This only needs to be provided if there is also a + * writefn and it masks out "unwritable" bits or has write-one-to-clear + * or similar behaviour. + */ + CPWriteFn *raw_writefn; + /* + * Function for resetting the register. If NULL, then reset will be done + * by writing resetvalue to the field specified in fieldoffset. If + * fieldoffset is 0 then no reset will be done. + */ + CPResetFn *resetfn; + + /* + * "Original" writefn and readfn. + * For ARMv8.1-VHE register aliases, we overwrite the read/write + * accessor functions of various EL1/EL0 to perform the runtime + * check for which sysreg should actually be modified, and then + * forwards the operation. Before overwriting the accessors, + * the original function is copied here, so that accesses that + * really do go to the EL1/EL0 version proceed normally. + * (The corresponding EL2 register is linked via opaque.) + */ + CPReadFn *orig_readfn; + CPWriteFn *orig_writefn; +}; + +/* + * Macros which are lvalues for the field in CPUARMState for the + * ARMCPRegInfo *ri. + */ +#define CPREG_FIELD32(env, ri) \ + (*(uint32_t *)((char *)(env) + (ri)->fieldoffset)) +#define CPREG_FIELD64(env, ri) \ + (*(uint64_t *)((char *)(env) + (ri)->fieldoffset)) + +#define REGINFO_SENTINEL { .type = ARM_CP_SENTINEL } + +void define_arm_cp_regs_with_opaque(ARMCPU *cpu, + const ARMCPRegInfo *regs, void *opaque); +void define_one_arm_cp_reg_with_opaque(ARMCPU *cpu, + const ARMCPRegInfo *regs, void *opaque); +static inline void define_arm_cp_regs(ARMCPU *cpu, const ARMCPRegInfo *regs) +{ + define_arm_cp_regs_with_opaque(cpu, regs, 0); +} +static inline void define_one_arm_cp_reg(ARMCPU *cpu, const ARMCPRegInfo *regs) +{ + define_one_arm_cp_reg_with_opaque(cpu, regs, 0); +} +const ARMCPRegInfo *get_arm_cp_reginfo(GHashTable *cpregs, uint32_t encoded_cp); + +/* + * Definition of an ARM co-processor register as viewed from + * userspace. This is used for presenting sanitised versions of + * registers to userspace when emulating the Linux AArch64 CPU + * ID/feature ABI (advertised as HWCAP_CPUID). + */ +typedef struct ARMCPRegUserSpaceInfo { + /* Name of register */ + const char *name; + + /* Is the name actually a glob pattern */ + bool is_glob; + + /* Only some bits are exported to user space */ + uint64_t exported_bits; + + /* Fixed bits are applied after the mask */ + uint64_t fixed_bits; +} ARMCPRegUserSpaceInfo; + +#define REGUSERINFO_SENTINEL { .name = NULL } + +void modify_arm_cp_regs(ARMCPRegInfo *regs, const ARMCPRegUserSpaceInfo *mods); + +/* CPWriteFn that can be used to implement writes-ignored behaviour */ +void arm_cp_write_ignore(CPUARMState *env, const ARMCPRegInfo *ri, + uint64_t value); +/* CPReadFn that can be used for read-as-zero behaviour */ +uint64_t arm_cp_read_zero(CPUARMState *env, const ARMCPRegInfo *ri); + +/* + * CPResetFn that does nothing, for use if no reset is required even + * if fieldoffset is non zero. + */ +void arm_cp_reset_ignore(CPUARMState *env, const ARMCPRegInfo *opaque); + +/* + * Return true if this reginfo struct's field in the cpu state struct + * is 64 bits wide. + */ +static inline bool cpreg_field_is_64bit(const ARMCPRegInfo *ri) +{ + return (ri->state == ARM_CP_STATE_AA64) || (ri->type & ARM_CP_64BIT); +} + +static inline bool cp_access_ok(int current_el, + const ARMCPRegInfo *ri, int isread) +{ + return (ri->access >> ((current_el * 2) + isread)) & 1; +} + +/* Raw read of a coprocessor register (as needed for migration, etc) */ +uint64_t read_raw_cp_reg(CPUARMState *env, const ARMCPRegInfo *ri); + +#endif /* TARGET_ARM_CPREGS_H */ |