Messages in this thread | | | From | Anup Patel <> | Date | Tue, 27 Aug 2019 15:06:55 +0530 | Subject | Re: [RFC PATCH 2/2] RISC-V: Add basic support for SBI v0.2 |
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On Tue, Aug 27, 2019 at 5:03 AM Atish Patra <atish.patra@wdc.com> wrote: > > The SBI v0.2 introduces a base extension which is backward compatible > with v0.1. Implement all helper functions and minimum required SBI > calls from v0.2 for now. All other base extension function will be > added later as per need. > > Signed-off-by: Atish Patra <atish.patra@wdc.com> > --- > arch/riscv/include/asm/sbi.h | 68 +++++++++++++++++++++++++++++------- > arch/riscv/kernel/Makefile | 1 + > arch/riscv/kernel/sbi.c | 50 ++++++++++++++++++++++++++ > arch/riscv/kernel/setup.c | 2 ++ > 4 files changed, 108 insertions(+), 13 deletions(-) > create mode 100644 arch/riscv/kernel/sbi.c > > diff --git a/arch/riscv/include/asm/sbi.h b/arch/riscv/include/asm/sbi.h > index 7f5ecaaaa0d7..4a4476956693 100644 > --- a/arch/riscv/include/asm/sbi.h > +++ b/arch/riscv/include/asm/sbi.h > @@ -8,7 +8,6 @@ > > #include <linux/types.h> > > - > #define SBI_EXT_LEGACY_SET_TIMER 0x0 > #define SBI_EXT_LEGACY_CONSOLE_PUTCHAR 0x1 > #define SBI_EXT_LEGACY_CONSOLE_GETCHAR 0x2 > @@ -19,28 +18,61 @@ > #define SBI_EXT_LEGACY_REMOTE_SFENCE_VMA_ASID 0x7 > #define SBI_EXT_LEGACY_SHUTDOWN 0x8 > > -#define SBI_CALL_LEGACY(which, arg0, arg1, arg2, arg3) ({ \ > +#define SBI_EXT_BASE 0x10 > + > +enum sbi_ext_base_fid { > + SBI_EXT_BASE_GET_SPEC_VERSION = 0, > + SBI_EXT_BASE_GET_IMP_ID, > + SBI_EXT_BASE_GET_IMP_VERSION, > + SBI_EXT_BASE_PROBE_EXT, > + SBI_EXT_BASE_GET_MVENDORID, > + SBI_EXT_BASE_GET_MARCHID, > + SBI_EXT_BASE_GET_MIMPID, > +}; > + > +#define SBI_CALL_LEGACY(ext, fid, arg0, arg1, arg2, arg3) ({ \ > register uintptr_t a0 asm ("a0") = (uintptr_t)(arg0); \ > register uintptr_t a1 asm ("a1") = (uintptr_t)(arg1); \ > register uintptr_t a2 asm ("a2") = (uintptr_t)(arg2); \ > register uintptr_t a3 asm ("a3") = (uintptr_t)(arg3); \ > - register uintptr_t a7 asm ("a7") = (uintptr_t)(which); \ > + register uintptr_t a6 asm ("a6") = (uintptr_t)(fid); \ > + register uintptr_t a7 asm ("a7") = (uintptr_t)(ext); \ > asm volatile ("ecall" \ > - : "+r" (a0) \ > - : "r" (a1), "r" (a2), "r" (a3), "r" (a7) \ > + : "+r" (a0), "+r" (a1) \ > + : "r" (a2), "r" (a3), "r" (a6), "r" (a7) \ > : "memory"); \ > a0; \ > })
I think instead of removing old convention we should use calling convention based on sbi_version detected at boot-time.
> > /* Lazy implementations until SBI is finalized */ > -#define SBI_CALL_LEGACY_0(which) SBI_CALL_LEGACY(which, 0, 0, 0, 0) > -#define SBI_CALL_LEGACY_1(which, arg0) SBI_CALL_LEGACY(which, arg0, 0, 0, 0) > -#define SBI_CALL_LEGACY_2(which, arg0, arg1) \ > - SBI_CALL_LEGACY(which, arg0, arg1, 0, 0) > -#define SBI_CALL_LEGACY_3(which, arg0, arg1, arg2) \ > - SBI_CALL_LEGACY(which, arg0, arg1, arg2, 0) > -#define SBI_CALL_LEGACY_4(which, arg0, arg1, arg2, arg3) \ > - SBI_CALL_LEGACY(which, arg0, arg1, arg2, arg3) > +#define SBI_CALL_LEGACY_0(ext) SBI_CALL_LEGACY(ext, 0, 0, 0, 0, 0) > +#define SBI_CALL_LEGACY_1(ext, arg0) SBI_CALL_LEGACY(ext, 0, arg0, 0, 0, 0) > +#define SBI_CALL_LEGACY_2(ext, arg0, arg1) \ > + SBI_CALL_LEGACY(ext, 0, arg0, arg1, 0, 0) > +#define SBI_CALL_LEGACY_3(ext, arg0, arg1, arg2) \ > + SBI_CALL_LEGACY(ext, 0, arg0, arg1, arg2, 0) > +#define SBI_CALL_LEGACY_4(ext, arg0, arg1, arg2, arg3) \ > + SBI_CALL_LEGACY(ext, 0, arg0, arg1, arg2, arg3) > + > +extern unsigned long sbi_firmware_version; > +struct sbiret { > + long error; > + long value; > +}; > + > +void riscv_sbi_init(void); > +struct sbiret riscv_sbi_ecall(int ext, int fid, int arg0, int arg1, > + int arg2, int arg3); > + > +#define SBI_CALL_0(ext, fid) riscv_sbi_ecall(ext, fid, 0, 0, 0, 0) > +#define SBI_CALL_1(ext, fid, arg0) riscv_sbi_ecall(ext, fid, arg0, 0, 0, 0) > +#define SBI_CALL_2(ext, fid, arg0, arg1) \ > + riscv_sbi_ecall(ext, fid, arg0, arg1, 0, 0) > +#define SBI_CALL_3(ext, fid, arg0, arg1, arg2) \ > + riscv_sbi_ecall(ext, fid, arg0, arg1, arg2, 0) > +#define SBI_CALL_4(ext, fid, arg0, arg1, arg2, arg3) \ > + riscv_sbi_ecall(ext, fid, arg0, arg1, arg2, arg3) > + > > static inline void sbi_console_putchar(int ch) > { > @@ -99,4 +131,14 @@ static inline void sbi_remote_sfence_vma_asid(const unsigned long *hart_mask, > start, size, asid); > }
To be sure that new kernels work fine on older kernel, we can be conservative and move all legacy SBI calls to kernel/sbi.c. All legacy SBI calls can check sbi_version and use appropriate SBI calling convention.
This might be redundant if we can ensure that newer kernels work fine with older SBI v0.1 firmwares.
> > +static inline unsigned long riscv_sbi_major_version(void) > +{ > + return (sbi_firmware_version >> 24) & 0x7f; > +} > + > +static inline unsigned long riscv_sbi_minor_version(void) > +{ > + return sbi_firmware_version & 0xffffff; > +} > + > #endif > diff --git a/arch/riscv/kernel/Makefile b/arch/riscv/kernel/Makefile > index 2420d37d96de..faf862d26924 100644 > --- a/arch/riscv/kernel/Makefile > +++ b/arch/riscv/kernel/Makefile > @@ -17,6 +17,7 @@ obj-y += irq.o > obj-y += process.o > obj-y += ptrace.o > obj-y += reset.o > +obj-y += sbi.o > obj-y += setup.o > obj-y += signal.o > obj-y += syscall_table.o > diff --git a/arch/riscv/kernel/sbi.c b/arch/riscv/kernel/sbi.c > new file mode 100644 > index 000000000000..457b8cc0e9d9 > --- /dev/null > +++ b/arch/riscv/kernel/sbi.c > @@ -0,0 +1,50 @@ > +// SPDX-License-Identifier: GPL-2.0-only > +/* > + * SBI initialilization and base extension implementation. > + * > + * Copyright (c) 2019 Western Digital Corporation or its affiliates. > + */ > + > +#include <asm/sbi.h> > +#include <linux/sched.h> > + > +unsigned long sbi_firmware_version;
Rename this too sbi_version or sbi_spec_version. The firmware version is different thing.
> + > +struct sbiret riscv_sbi_ecall(int ext, int fid, int arg0, int arg1, > + int arg2, int arg3) > +{ > + struct sbiret ret; > + > + register uintptr_t a0 asm ("a0") = (uintptr_t)(arg0); > + register uintptr_t a1 asm ("a1") = (uintptr_t)(arg1); > + register uintptr_t a2 asm ("a2") = (uintptr_t)(arg2); > + register uintptr_t a3 asm ("a3") = (uintptr_t)(arg3); > + register uintptr_t a6 asm ("a6") = (uintptr_t)(fid); > + register uintptr_t a7 asm ("a7") = (uintptr_t)(ext); > + asm volatile ("ecall" > + : "+r" (a0), "+r" (a1) > + : "r" (a2), "r" (a3), "r" (a6), "r" (a7) > + : "memory"); > + ret.error = a0; > + ret.value = a1; > + > + return ret; > +} > + > +static struct sbiret sbi_get_spec_version(void) > +{ > + return SBI_CALL_0(SBI_EXT_BASE, SBI_EXT_BASE_GET_SPEC_VERSION); > +} > + > +void riscv_sbi_init(void) > +{ > + struct sbiret ret; > + > + /* legacy SBI version*/ > + sbi_firmware_version = 0x1; > + ret = sbi_get_spec_version(); > + if (!ret.error) > + sbi_firmware_version = ret.value; > + pr_info("SBI version implemented in firmware [%lu:%lu]\n", > + riscv_sbi_major_version(), riscv_sbi_minor_version());
Should we not print SBI implementation ID and SBI firmware version.
Regards, Anup
> +} > diff --git a/arch/riscv/kernel/setup.c b/arch/riscv/kernel/setup.c > index a990a6cb184f..4c324fd398c8 100644 > --- a/arch/riscv/kernel/setup.c > +++ b/arch/riscv/kernel/setup.c > @@ -21,6 +21,7 @@ > #include <asm/sections.h> > #include <asm/pgtable.h> > #include <asm/smp.h> > +#include <asm/sbi.h> > #include <asm/tlbflush.h> > #include <asm/thread_info.h> > > @@ -70,6 +71,7 @@ void __init setup_arch(char **cmdline_p) > swiotlb_init(1); > #endif > > + riscv_sbi_init(); > #ifdef CONFIG_SMP > setup_smp(); > #endif > -- > 2.21.0 >
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