linux/arch/riscv/include/asm/csr.h

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/* SPDX-License-Identifier: GPL-2.0-only */
/*
* Copyright (C) 2015 Regents of the University of California
*/
#ifndef _ASM_RISCV_CSR_H
#define _ASM_RISCV_CSR_H
#include <asm/asm.h>
#include <linux/const.h>
/* Status register flags */
#define SR_SIE _AC(0x00000002, UL) /* Supervisor Interrupt Enable */
#define SR_MIE _AC(0x00000008, UL) /* Machine Interrupt Enable */
#define SR_SPIE _AC(0x00000020, UL) /* Previous Supervisor IE */
#define SR_MPIE _AC(0x00000080, UL) /* Previous Machine IE */
#define SR_SPP _AC(0x00000100, UL) /* Previously Supervisor */
#define SR_MPP _AC(0x00001800, UL) /* Previously Machine */
#define SR_SUM _AC(0x00040000, UL) /* Supervisor User Memory Access */
#define SR_FS _AC(0x00006000, UL) /* Floating-point Status */
#define SR_FS_OFF _AC(0x00000000, UL)
#define SR_FS_INITIAL _AC(0x00002000, UL)
#define SR_FS_CLEAN _AC(0x00004000, UL)
#define SR_FS_DIRTY _AC(0x00006000, UL)
#define SR_XS _AC(0x00018000, UL) /* Extension Status */
#define SR_XS_OFF _AC(0x00000000, UL)
#define SR_XS_INITIAL _AC(0x00008000, UL)
#define SR_XS_CLEAN _AC(0x00010000, UL)
#define SR_XS_DIRTY _AC(0x00018000, UL)
#ifndef CONFIG_64BIT
#define SR_SD _AC(0x80000000, UL) /* FS/XS dirty */
#else
#define SR_SD _AC(0x8000000000000000, UL) /* FS/XS dirty */
#endif
/* SATP flags */
#ifndef CONFIG_64BIT
#define SATP_PPN _AC(0x003FFFFF, UL)
#define SATP_MODE_32 _AC(0x80000000, UL)
#define SATP_MODE SATP_MODE_32
RISC-V: Implement ASID allocator Currently, we do local TLB flush on every MM switch. This is very harsh on performance because we are forcing page table walks after every MM switch. This patch implements ASID allocator for assigning an ASID to a MM context. The number of ASIDs are limited in HW so we create a logical entity named CONTEXTID for assigning to MM context. The lower bits of CONTEXTID are ASID and upper bits are VERSION number. The number of usable ASID bits supported by HW are detected at boot-time by writing 1s to ASID bits in SATP CSR. We allocate new CONTEXTID on first MM switch for a MM context where the ASID is allocated from an ASID bitmap and VERSION is provide by an atomic counter. At time of allocating new CONTEXTID, if we run out of available ASIDs then: 1. We flush the ASID bitmap 2. Increment current VERSION atomic counter 3. Re-allocate ASID from ASID bitmap 4. Flush TLB on all CPUs 5. Try CONTEXTID re-assignment on all CPUs Please note that we don't use ASID #0 because it is used at boot-time by all CPUs for initial MM context. Also, newly created context is always assigned CONTEXTID #0 (i.e. VERSION #0 and ASID #0) which is an invalid context in our implementation. Using above approach, we have virtually infinite CONTEXTIDs on-top-of limited number of HW ASIDs. This approach is inspired from ASID allocator used for Linux ARM/ARM64 but we have adapted it for RISC-V. Overall, this ASID allocator helps us reduce rate of local TLB flushes on every CPU thereby increasing performance. This patch is tested on QEMU virt machine, Spike and SiFive Unleashed board. On QEMU virt machine, we see some (3-5% approx) performance improvement with SW emulated TLBs provided by QEMU. Unfortunately, the ASID bits of the SATP CSR are not implemented on Spike and SiFive Unleashed board so we don't see any change in performance. On real HW having all ASID bits implemented, the performance gains will be much more due improved sharing of TLB among different processes. Signed-off-by: Anup Patel <anup.patel@wdc.com> Reviewed-by: Palmer Dabbelt <palmerdabbelt@google.com> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2021-02-03 09:49:07 +00:00
#define SATP_ASID_BITS 9
#define SATP_ASID_SHIFT 22
#define SATP_ASID_MASK _AC(0x1FF, UL)
#else
#define SATP_PPN _AC(0x00000FFFFFFFFFFF, UL)
#define SATP_MODE_39 _AC(0x8000000000000000, UL)
#define SATP_MODE SATP_MODE_39
RISC-V: Implement ASID allocator Currently, we do local TLB flush on every MM switch. This is very harsh on performance because we are forcing page table walks after every MM switch. This patch implements ASID allocator for assigning an ASID to a MM context. The number of ASIDs are limited in HW so we create a logical entity named CONTEXTID for assigning to MM context. The lower bits of CONTEXTID are ASID and upper bits are VERSION number. The number of usable ASID bits supported by HW are detected at boot-time by writing 1s to ASID bits in SATP CSR. We allocate new CONTEXTID on first MM switch for a MM context where the ASID is allocated from an ASID bitmap and VERSION is provide by an atomic counter. At time of allocating new CONTEXTID, if we run out of available ASIDs then: 1. We flush the ASID bitmap 2. Increment current VERSION atomic counter 3. Re-allocate ASID from ASID bitmap 4. Flush TLB on all CPUs 5. Try CONTEXTID re-assignment on all CPUs Please note that we don't use ASID #0 because it is used at boot-time by all CPUs for initial MM context. Also, newly created context is always assigned CONTEXTID #0 (i.e. VERSION #0 and ASID #0) which is an invalid context in our implementation. Using above approach, we have virtually infinite CONTEXTIDs on-top-of limited number of HW ASIDs. This approach is inspired from ASID allocator used for Linux ARM/ARM64 but we have adapted it for RISC-V. Overall, this ASID allocator helps us reduce rate of local TLB flushes on every CPU thereby increasing performance. This patch is tested on QEMU virt machine, Spike and SiFive Unleashed board. On QEMU virt machine, we see some (3-5% approx) performance improvement with SW emulated TLBs provided by QEMU. Unfortunately, the ASID bits of the SATP CSR are not implemented on Spike and SiFive Unleashed board so we don't see any change in performance. On real HW having all ASID bits implemented, the performance gains will be much more due improved sharing of TLB among different processes. Signed-off-by: Anup Patel <anup.patel@wdc.com> Reviewed-by: Palmer Dabbelt <palmerdabbelt@google.com> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2021-02-03 09:49:07 +00:00
#define SATP_ASID_BITS 16
#define SATP_ASID_SHIFT 44
#define SATP_ASID_MASK _AC(0xFFFF, UL)
#endif
/* Exception cause high bit - is an interrupt if set */
#define CAUSE_IRQ_FLAG (_AC(1, UL) << (__riscv_xlen - 1))
/* Interrupt causes (minus the high bit) */
#define IRQ_S_SOFT 1
#define IRQ_M_SOFT 3
#define IRQ_S_TIMER 5
#define IRQ_M_TIMER 7
#define IRQ_S_EXT 9
#define IRQ_M_EXT 11
/* Exception causes */
#define EXC_INST_MISALIGNED 0
#define EXC_INST_ACCESS 1
#define EXC_BREAKPOINT 3
#define EXC_LOAD_ACCESS 5
#define EXC_STORE_ACCESS 7
#define EXC_SYSCALL 8
#define EXC_INST_PAGE_FAULT 12
#define EXC_LOAD_PAGE_FAULT 13
#define EXC_STORE_PAGE_FAULT 15
/* PMP configuration */
#define PMP_R 0x01
#define PMP_W 0x02
#define PMP_X 0x04
#define PMP_A 0x18
#define PMP_A_TOR 0x08
#define PMP_A_NA4 0x10
#define PMP_A_NAPOT 0x18
#define PMP_L 0x80
/* symbolic CSR names: */
#define CSR_CYCLE 0xc00
#define CSR_TIME 0xc01
#define CSR_INSTRET 0xc02
#define CSR_CYCLEH 0xc80
#define CSR_TIMEH 0xc81
#define CSR_INSTRETH 0xc82
#define CSR_SSTATUS 0x100
#define CSR_SIE 0x104
#define CSR_STVEC 0x105
#define CSR_SCOUNTEREN 0x106
#define CSR_SSCRATCH 0x140
#define CSR_SEPC 0x141
#define CSR_SCAUSE 0x142
#define CSR_STVAL 0x143
#define CSR_SIP 0x144
#define CSR_SATP 0x180
#define CSR_MSTATUS 0x300
#define CSR_MISA 0x301
#define CSR_MIE 0x304
#define CSR_MTVEC 0x305
#define CSR_MSCRATCH 0x340
#define CSR_MEPC 0x341
#define CSR_MCAUSE 0x342
#define CSR_MTVAL 0x343
#define CSR_MIP 0x344
#define CSR_PMPCFG0 0x3a0
#define CSR_PMPADDR0 0x3b0
#define CSR_MVENDORID 0xf11
#define CSR_MARCHID 0xf12
#define CSR_MIMPID 0xf13
#define CSR_MHARTID 0xf14
#ifdef CONFIG_RISCV_M_MODE
# define CSR_STATUS CSR_MSTATUS
# define CSR_IE CSR_MIE
# define CSR_TVEC CSR_MTVEC
# define CSR_SCRATCH CSR_MSCRATCH
# define CSR_EPC CSR_MEPC
# define CSR_CAUSE CSR_MCAUSE
# define CSR_TVAL CSR_MTVAL
# define CSR_IP CSR_MIP
# define SR_IE SR_MIE
# define SR_PIE SR_MPIE
# define SR_PP SR_MPP
# define RV_IRQ_SOFT IRQ_M_SOFT
# define RV_IRQ_TIMER IRQ_M_TIMER
# define RV_IRQ_EXT IRQ_M_EXT
#else /* CONFIG_RISCV_M_MODE */
# define CSR_STATUS CSR_SSTATUS
# define CSR_IE CSR_SIE
# define CSR_TVEC CSR_STVEC
# define CSR_SCRATCH CSR_SSCRATCH
# define CSR_EPC CSR_SEPC
# define CSR_CAUSE CSR_SCAUSE
# define CSR_TVAL CSR_STVAL
# define CSR_IP CSR_SIP
# define SR_IE SR_SIE
# define SR_PIE SR_SPIE
# define SR_PP SR_SPP
# define RV_IRQ_SOFT IRQ_S_SOFT
# define RV_IRQ_TIMER IRQ_S_TIMER
# define RV_IRQ_EXT IRQ_S_EXT
#endif /* CONFIG_RISCV_M_MODE */
/* IE/IP (Supervisor/Machine Interrupt Enable/Pending) flags */
#define IE_SIE (_AC(0x1, UL) << RV_IRQ_SOFT)
#define IE_TIE (_AC(0x1, UL) << RV_IRQ_TIMER)
#define IE_EIE (_AC(0x1, UL) << RV_IRQ_EXT)
#ifndef __ASSEMBLY__
#define csr_swap(csr, val) \
({ \
unsigned long __v = (unsigned long)(val); \
__asm__ __volatile__ ("csrrw %0, " __ASM_STR(csr) ", %1"\
: "=r" (__v) : "rK" (__v) \
: "memory"); \
__v; \
})
#define csr_read(csr) \
({ \
register unsigned long __v; \
__asm__ __volatile__ ("csrr %0, " __ASM_STR(csr) \
: "=r" (__v) : \
: "memory"); \
__v; \
})
#define csr_write(csr, val) \
({ \
unsigned long __v = (unsigned long)(val); \
__asm__ __volatile__ ("csrw " __ASM_STR(csr) ", %0" \
: : "rK" (__v) \
: "memory"); \
})
#define csr_read_set(csr, val) \
({ \
unsigned long __v = (unsigned long)(val); \
__asm__ __volatile__ ("csrrs %0, " __ASM_STR(csr) ", %1"\
: "=r" (__v) : "rK" (__v) \
: "memory"); \
__v; \
})
#define csr_set(csr, val) \
({ \
unsigned long __v = (unsigned long)(val); \
__asm__ __volatile__ ("csrs " __ASM_STR(csr) ", %0" \
: : "rK" (__v) \
: "memory"); \
})
#define csr_read_clear(csr, val) \
({ \
unsigned long __v = (unsigned long)(val); \
__asm__ __volatile__ ("csrrc %0, " __ASM_STR(csr) ", %1"\
: "=r" (__v) : "rK" (__v) \
: "memory"); \
__v; \
})
#define csr_clear(csr, val) \
({ \
unsigned long __v = (unsigned long)(val); \
__asm__ __volatile__ ("csrc " __ASM_STR(csr) ", %0" \
: : "rK" (__v) \
: "memory"); \
})
#endif /* __ASSEMBLY__ */
#endif /* _ASM_RISCV_CSR_H */