Messages in this thread | | | From | Atish Patra <> | Subject | Re: [RFC PATCH 2/2] RISC-V: Add basic support for SBI v0.2 | Date | Tue, 27 Aug 2019 20:43:13 +0000 |
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On Tue, 2019-08-27 at 15:06 +0530, Anup Patel wrote: > 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.
Yes that's why I didnot want to do it first time. How about this ?
Use only 0.2 convention only and get rid of the 0.1 convention. As it is anyways backward compatible with 0.1, we don't need a if else clause.
The legacy calls will not use any value set in a1 and always set 0 in function id (a6).
> > > +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. >
ok.
> > + > > +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. >
Eventually yes. I wanted to have this series minimal implementation and build upon it.
I will go ahead and add those.
> 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 > >
-- Regards, Atish
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