[U-Boot] [PATCH 2/2] riscv: Access CSRs using CSR numbers
Auer, Lukas
lukas.auer at aisec.fraunhofer.de
Thu Jul 18 08:52:51 UTC 2019
Hi Bin,
On Wed, 2019-07-10 at 23:43 -0700, Bin Meng wrote:
> We should prefer accessing CSRs using their CSR numbers
> because:
> 1. It compiles fine with older toolchains.
> 2. We can use latest CSR names in #define macro names of CSR
> numbers as-per RISC-V spec.
> 3. We can access newly added CSRs even if toolchain does not
> recognize newly added CSRs by name.
>
> This commit is inspired from Linux kernel commit a3182c91ef4e
> ("RISC-V: Access CSRs using CSR numbers").
>
> Signed-off-by: Bin Meng <bmeng.cn at gmail.com>
> ---
>
> arch/riscv/cpu/cpu.c | 9 +-
> arch/riscv/cpu/start.S | 3 +-
> arch/riscv/include/asm/csr.h | 12 ++
> arch/riscv/include/asm/encoding.h | 238 +-------------------------------------
> 4 files changed, 19 insertions(+), 243 deletions(-)
>
> diff --git a/arch/riscv/cpu/cpu.c b/arch/riscv/cpu/cpu.c
> index e9a8b43..5ca1857 100644
> --- a/arch/riscv/cpu/cpu.c
> +++ b/arch/riscv/cpu/cpu.c
> @@ -7,7 +7,6 @@
> #include <cpu.h>
> #include <dm.h>
> #include <log.h>
> -#include <asm/csr.h>
> #include <asm/encoding.h>
> #include <dm/uclass-internal.h>
>
> @@ -48,7 +47,7 @@ static inline bool supports_extension(char ext)
> return false;
> #else /* !CONFIG_CPU */
> #ifdef CONFIG_RISCV_MMODE
> - return csr_read(misa) & (1 << (ext - 'a'));
> + return csr_read(CSR_MISA) & (1 << (ext - 'a'));
> #else /* !CONFIG_RISCV_MMODE */
> #warning "There is no way to determine the available extensions in S-mode."
> #warning "Please convert your board to use the RISC-V CPU driver."
> @@ -82,7 +81,7 @@ int arch_cpu_init_dm(void)
> /* Enable FPU */
> if (supports_extension('d') || supports_extension('f')) {
> csr_set(MODE_PREFIX(status), MSTATUS_FS);
> - csr_write(fcsr, 0);
> + csr_write(CSR_FCSR, 0);
> }
>
> if (CONFIG_IS_ENABLED(RISCV_MMODE)) {
> @@ -90,11 +89,11 @@ int arch_cpu_init_dm(void)
> * Enable perf counters for cycle, time,
> * and instret counters only
> */
> - csr_write(mcounteren, GENMASK(2, 0));
> + csr_write(CSR_MCOUNTEREN, GENMASK(2, 0));
>
> /* Disable paging */
> if (supports_extension('s'))
> - csr_write(satp, 0);
> + csr_write(CSR_SATP, 0);
> }
>
> return 0;
> diff --git a/arch/riscv/cpu/start.S b/arch/riscv/cpu/start.S
> index 60ac8c6..e06db40 100644
> --- a/arch/riscv/cpu/start.S
> +++ b/arch/riscv/cpu/start.S
> @@ -13,7 +13,6 @@
> #include <config.h>
> #include <common.h>
> #include <elf.h>
> -#include <asm/csr.h>
> #include <asm/encoding.h>
> #include <generated/asm-offsets.h>
>
> @@ -41,7 +40,7 @@ secondary_harts_relocation_error:
> .globl _start
> _start:
> #ifdef CONFIG_RISCV_MMODE
> - csrr a0, mhartid
> + csrr a0, CSR_MHARTID
> #endif
>
> /* save hart id and dtb pointer */
> diff --git a/arch/riscv/include/asm/csr.h b/arch/riscv/include/asm/csr.h
> index 1a6bcfc..d152074 100644
> --- a/arch/riscv/include/asm/csr.h
> +++ b/arch/riscv/include/asm/csr.h
> @@ -75,6 +75,7 @@
> #define SIE_STIE (_AC(0x1, UL) << IRQ_S_TIMER)
> #define SIE_SEIE (_AC(0x1, UL) << IRQ_S_EXT)
>
> +#define CSR_FCSR 0x003
> #define CSR_CYCLE 0xc00
> #define CSR_TIME 0xc01
> #define CSR_INSTRET 0xc02
> @@ -88,9 +89,20 @@
> #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_MCOUNTEREN 0x306
> +#define CSR_MSCRATCH 0x340
> +#define CSR_MEPC 0x341
> +#define CSR_MCAUSE 0x342
> +#define CSR_MTVAL 0x343
> +#define CSR_MIP 0x344
> #define CSR_CYCLEH 0xc80
> #define CSR_TIMEH 0xc81
> #define CSR_INSTRETH 0xc82
> +#define CSR_MHARTID 0xf14
>
> #ifndef __ASSEMBLY__
>
> diff --git a/arch/riscv/include/asm/encoding.h b/arch/riscv/include/asm/encoding.h
> index 772668c..c450eb9 100644
> --- a/arch/riscv/include/asm/encoding.h
> +++ b/arch/riscv/include/asm/encoding.h
> @@ -7,6 +7,8 @@
> #ifndef RISCV_CSR_ENCODING_H
> #define RISCV_CSR_ENCODING_H
>
> +#include <asm/csr.h>
> +
> #ifdef CONFIG_RISCV_SMODE
> #define MODE_PREFIX(__suffix) s##__suffix
> #else
> @@ -49,13 +51,10 @@
> #define SSTATUS64_SD 0x8000000000000000
>
> #define MIP_SSIP BIT(IRQ_S_SOFT)
> -#define MIP_HSIP BIT(IRQ_H_SOFT)
> #define MIP_MSIP BIT(IRQ_M_SOFT)
> #define MIP_STIP BIT(IRQ_S_TIMER)
> -#define MIP_HTIP BIT(IRQ_H_TIMER)
> #define MIP_MTIP BIT(IRQ_M_TIMER)
> #define MIP_SEIP BIT(IRQ_S_EXT)
> -#define MIP_HEIP BIT(IRQ_H_EXT)
> #define MIP_MEIP BIT(IRQ_M_EXT)
>
> #define SIP_SSIP MIP_SSIP
> @@ -73,18 +72,6 @@
> #define VM_SV39 9
> #define VM_SV48 10
>
> -#define IRQ_S_SOFT 1
> -#define IRQ_H_SOFT 2
> -#define IRQ_M_SOFT 3
> -#define IRQ_S_TIMER 5
> -#define IRQ_H_TIMER 6
> -#define IRQ_M_TIMER 7
> -#define IRQ_S_EXT 9
> -#define IRQ_H_EXT 10
> -#define IRQ_M_EXT 11
> -#define IRQ_COP 12
> -#define IRQ_HOST 13
> -
> #define CAUSE_MISALIGNED_FETCH 0
> #define CAUSE_FETCH_ACCESS 1
> #define CAUSE_ILLEGAL_INSTRUCTION 2
> @@ -167,227 +154,6 @@
> #define RISCV_PGSHIFT 12
> #define RISCV_PGSIZE BIT(RISCV_PGSHIFT)
>
> -/* CSR numbers */
> -#define CSR_FFLAGS 0x1
> -#define CSR_FRM 0x2
> -#define CSR_FCSR 0x3
> -
> -#define CSR_SSTATUS 0x100
> -#define CSR_SEDELEG 0x102
> -#define CSR_SIDELEG 0x103
> -#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_MEDELEG 0x302
> -#define CSR_MIDELEG 0x303
> -#define CSR_MIE 0x304
> -#define CSR_MTVEC 0x305
> -#define CSR_MCOUNTEREN 0x306
> -#define CSR_MHPMEVENT3 0x323
> -#define CSR_MHPMEVENT4 0x324
> -#define CSR_MHPMEVENT5 0x325
> -#define CSR_MHPMEVENT6 0x326
> -#define CSR_MHPMEVENT7 0x327
> -#define CSR_MHPMEVENT8 0x328
> -#define CSR_MHPMEVENT9 0x329
> -#define CSR_MHPMEVENT10 0x32a
> -#define CSR_MHPMEVENT11 0x32b
> -#define CSR_MHPMEVENT12 0x32c
> -#define CSR_MHPMEVENT13 0x32d
> -#define CSR_MHPMEVENT14 0x32e
> -#define CSR_MHPMEVENT15 0x32f
> -#define CSR_MHPMEVENT16 0x330
> -#define CSR_MHPMEVENT17 0x331
> -#define CSR_MHPMEVENT18 0x332
> -#define CSR_MHPMEVENT19 0x333
> -#define CSR_MHPMEVENT20 0x334
> -#define CSR_MHPMEVENT21 0x335
> -#define CSR_MHPMEVENT22 0x336
> -#define CSR_MHPMEVENT23 0x337
> -#define CSR_MHPMEVENT24 0x338
> -#define CSR_MHPMEVENT25 0x339
> -#define CSR_MHPMEVENT26 0x33a
> -#define CSR_MHPMEVENT27 0x33b
> -#define CSR_MHPMEVENT28 0x33c
> -#define CSR_MHPMEVENT29 0x33d
> -#define CSR_MHPMEVENT30 0x33e
> -#define CSR_MHPMEVENT31 0x33f
> -#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_PMPCFG1 0x3a1
> -#define CSR_PMPCFG2 0x3a2
> -#define CSR_PMPCFG3 0x3a3
> -#define CSR_PMPADDR0 0x3b0
> -#define CSR_PMPADDR1 0x3b1
> -#define CSR_PMPADDR2 0x3b2
> -#define CSR_PMPADDR3 0x3b3
> -#define CSR_PMPADDR4 0x3b4
> -#define CSR_PMPADDR5 0x3b5
> -#define CSR_PMPADDR6 0x3b6
> -#define CSR_PMPADDR7 0x3b7
> -#define CSR_PMPADDR8 0x3b8
> -#define CSR_PMPADDR9 0x3b9
> -#define CSR_PMPADDR10 0x3ba
> -#define CSR_PMPADDR11 0x3bb
> -#define CSR_PMPADDR12 0x3bc
> -#define CSR_PMPADDR13 0x3bd
> -#define CSR_PMPADDR14 0x3be
> -#define CSR_PMPADDR15 0x3bf
> -
> -#define CSR_TSELECT 0x7a0
> -#define CSR_TDATA1 0x7a1
> -#define CSR_TDATA2 0x7a2
> -#define CSR_TDATA3 0x7a3
> -#define CSR_DCSR 0x7b0
> -#define CSR_DPC 0x7b1
> -#define CSR_DSCRATCH 0x7b2
> -
> -#define CSR_MCYCLE 0xb00
> -#define CSR_MINSTRET 0xb02
> -#define CSR_MHPMCOUNTER3 0xb03
> -#define CSR_MHPMCOUNTER4 0xb04
> -#define CSR_MHPMCOUNTER5 0xb05
> -#define CSR_MHPMCOUNTER6 0xb06
> -#define CSR_MHPMCOUNTER7 0xb07
> -#define CSR_MHPMCOUNTER8 0xb08
> -#define CSR_MHPMCOUNTER9 0xb09
> -#define CSR_MHPMCOUNTER10 0xb0a
> -#define CSR_MHPMCOUNTER11 0xb0b
> -#define CSR_MHPMCOUNTER12 0xb0c
> -#define CSR_MHPMCOUNTER13 0xb0d
> -#define CSR_MHPMCOUNTER14 0xb0e
> -#define CSR_MHPMCOUNTER15 0xb0f
> -#define CSR_MHPMCOUNTER16 0xb10
> -#define CSR_MHPMCOUNTER17 0xb11
> -#define CSR_MHPMCOUNTER18 0xb12
> -#define CSR_MHPMCOUNTER19 0xb13
> -#define CSR_MHPMCOUNTER20 0xb14
> -#define CSR_MHPMCOUNTER21 0xb15
> -#define CSR_MHPMCOUNTER22 0xb16
> -#define CSR_MHPMCOUNTER23 0xb17
> -#define CSR_MHPMCOUNTER24 0xb18
> -#define CSR_MHPMCOUNTER25 0xb19
> -#define CSR_MHPMCOUNTER26 0xb1a
> -#define CSR_MHPMCOUNTER27 0xb1b
> -#define CSR_MHPMCOUNTER28 0xb1c
> -#define CSR_MHPMCOUNTER29 0xb1d
> -#define CSR_MHPMCOUNTER30 0xb1e
> -#define CSR_MHPMCOUNTER31 0xb1f
> -#define CSR_MCYCLEH 0xb80
> -#define CSR_MINSTRETH 0xb82
> -#define CSR_MHPMCOUNTER3H 0xb83
> -#define CSR_MHPMCOUNTER4H 0xb84
> -#define CSR_MHPMCOUNTER5H 0xb85
> -#define CSR_MHPMCOUNTER6H 0xb86
> -#define CSR_MHPMCOUNTER7H 0xb87
> -#define CSR_MHPMCOUNTER8H 0xb88
> -#define CSR_MHPMCOUNTER9H 0xb89
> -#define CSR_MHPMCOUNTER10H 0xb8a
> -#define CSR_MHPMCOUNTER11H 0xb8b
> -#define CSR_MHPMCOUNTER12H 0xb8c
> -#define CSR_MHPMCOUNTER13H 0xb8d
> -#define CSR_MHPMCOUNTER14H 0xb8e
> -#define CSR_MHPMCOUNTER15H 0xb8f
> -#define CSR_MHPMCOUNTER16H 0xb90
> -#define CSR_MHPMCOUNTER17H 0xb91
> -#define CSR_MHPMCOUNTER18H 0xb92
> -#define CSR_MHPMCOUNTER19H 0xb93
> -#define CSR_MHPMCOUNTER20H 0xb94
> -#define CSR_MHPMCOUNTER21H 0xb95
> -#define CSR_MHPMCOUNTER22H 0xb96
> -#define CSR_MHPMCOUNTER23H 0xb97
> -#define CSR_MHPMCOUNTER24H 0xb98
> -#define CSR_MHPMCOUNTER25H 0xb99
> -#define CSR_MHPMCOUNTER26H 0xb9a
> -#define CSR_MHPMCOUNTER27H 0xb9b
> -#define CSR_MHPMCOUNTER28H 0xb9c
> -#define CSR_MHPMCOUNTER29H 0xb9d
> -#define CSR_MHPMCOUNTER30H 0xb9e
> -#define CSR_MHPMCOUNTER31H 0xb9f
> -
> -#define CSR_CYCLE 0xc00
> -#define CSR_TIME 0xc01
> -#define CSR_INSTRET 0xc02
> -#define CSR_HPMCOUNTER3 0xc03
> -#define CSR_HPMCOUNTER4 0xc04
> -#define CSR_HPMCOUNTER5 0xc05
> -#define CSR_HPMCOUNTER6 0xc06
> -#define CSR_HPMCOUNTER7 0xc07
> -#define CSR_HPMCOUNTER8 0xc08
> -#define CSR_HPMCOUNTER9 0xc09
> -#define CSR_HPMCOUNTER10 0xc0a
> -#define CSR_HPMCOUNTER11 0xc0b
> -#define CSR_HPMCOUNTER12 0xc0c
> -#define CSR_HPMCOUNTER13 0xc0d
> -#define CSR_HPMCOUNTER14 0xc0e
> -#define CSR_HPMCOUNTER15 0xc0f
> -#define CSR_HPMCOUNTER16 0xc10
> -#define CSR_HPMCOUNTER17 0xc11
> -#define CSR_HPMCOUNTER18 0xc12
> -#define CSR_HPMCOUNTER19 0xc13
> -#define CSR_HPMCOUNTER20 0xc14
> -#define CSR_HPMCOUNTER21 0xc15
> -#define CSR_HPMCOUNTER22 0xc16
> -#define CSR_HPMCOUNTER23 0xc17
> -#define CSR_HPMCOUNTER24 0xc18
> -#define CSR_HPMCOUNTER25 0xc19
> -#define CSR_HPMCOUNTER26 0xc1a
> -#define CSR_HPMCOUNTER27 0xc1b
> -#define CSR_HPMCOUNTER28 0xc1c
> -#define CSR_HPMCOUNTER29 0xc1d
> -#define CSR_HPMCOUNTER30 0xc1e
> -#define CSR_HPMCOUNTER31 0xc1f
> -#define CSR_CYCLEH 0xc80
> -#define CSR_TIMEH 0xc81
> -#define CSR_INSTRETH 0xc82
> -#define CSR_HPMCOUNTER3H 0xc83
> -#define CSR_HPMCOUNTER4H 0xc84
> -#define CSR_HPMCOUNTER5H 0xc85
> -#define CSR_HPMCOUNTER6H 0xc86
> -#define CSR_HPMCOUNTER7H 0xc87
> -#define CSR_HPMCOUNTER8H 0xc88
> -#define CSR_HPMCOUNTER9H 0xc89
> -#define CSR_HPMCOUNTER10H 0xc8a
> -#define CSR_HPMCOUNTER11H 0xc8b
> -#define CSR_HPMCOUNTER12H 0xc8c
> -#define CSR_HPMCOUNTER13H 0xc8d
> -#define CSR_HPMCOUNTER14H 0xc8e
> -#define CSR_HPMCOUNTER15H 0xc8f
> -#define CSR_HPMCOUNTER16H 0xc90
> -#define CSR_HPMCOUNTER17H 0xc91
> -#define CSR_HPMCOUNTER18H 0xc92
> -#define CSR_HPMCOUNTER19H 0xc93
> -#define CSR_HPMCOUNTER20H 0xc94
> -#define CSR_HPMCOUNTER21H 0xc95
> -#define CSR_HPMCOUNTER22H 0xc96
> -#define CSR_HPMCOUNTER23H 0xc97
> -#define CSR_HPMCOUNTER24H 0xc98
> -#define CSR_HPMCOUNTER25H 0xc99
> -#define CSR_HPMCOUNTER26H 0xc9a
> -#define CSR_HPMCOUNTER27H 0xc9b
> -#define CSR_HPMCOUNTER28H 0xc9c
> -#define CSR_HPMCOUNTER29H 0xc9d
> -#define CSR_HPMCOUNTER30H 0xc9e
> -#define CSR_HPMCOUNTER31H 0xc9f
> -
> -#define CSR_MVENDORID 0xf11
> -#define CSR_MARCHID 0xf12
> -#define CSR_MIMPID 0xf13
> -#define CSR_MHARTID 0xf14
> -
Why are you removing all CSR_* definitions here?
The patch looks good and it is a very good idea to only use CSR
numbers. There are still two places left, where we are using CSR names.
The first is in the MODE_PREFIX macro. That should only be a matter of
changing it to CSR_M/S##__suffix and capitalizing the suffix in all
uses of the macro.
The second one is in cpu/ax25/cache.c. Rick, can you maybe add a patch
to your cache series to convert that file to using CSR numbers instead
of names? That would also allow us to build the board in Travis with
the cache enabled.
Thanks,
Lukas
> #endif /* __riscv */
>
> #endif /* RISCV_CSR_ENCODING_H */
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