Messages in this thread | | | Date | Thu, 6 Jul 2023 12:44:07 -0700 | From | Charlie Jenkins <> | Subject | Re: [PATCH 1/3] RISC-V: Framework for vendor extensions |
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On Thu, Jul 06, 2023 at 07:29:37PM +0300, Rémi Denis-Courmont wrote: > Le torstaina 6. heinäkuuta 2023, 6.30.17 EEST Charlie Jenkins a écrit : > > Create Kconfig files, Makefiles, and functions to enable vendors to > > provide information via the riscv_hwprobe syscall about which vendor > > extensions are available. > > > > Signed-off-by: Charlie Jenkins <charlie@rivosinc.com> > > --- > > arch/riscv/Kbuild | 1 + > > arch/riscv/Kconfig | 1 + > > arch/riscv/Kconfig.vendor | 3 +++ > > arch/riscv/include/asm/hwprobe.h | 1 + > > arch/riscv/kernel/sys_riscv.c | 40 > > ++++++++++++++++++++++++++++++++--- arch/riscv/vendor_extensions/Makefile | > > 3 +++ > > 6 files changed, 46 insertions(+), 3 deletions(-) > > > > diff --git a/arch/riscv/Kbuild b/arch/riscv/Kbuild > > index afa83e307a2e..bea38010d9db 100644 > > --- a/arch/riscv/Kbuild > > +++ b/arch/riscv/Kbuild > > @@ -3,6 +3,7 @@ > > obj-y += kernel/ mm/ net/ > > obj-$(CONFIG_BUILTIN_DTB) += boot/dts/ > > obj-y += errata/ > > +obj-y += vendor_extensions/ > > obj-$(CONFIG_KVM) += kvm/ > > > > obj-$(CONFIG_ARCH_HAS_KEXEC_PURGATORY) += purgatory/ > > diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig > > index c1505c7729ec..19404ede0ee3 100644 > > --- a/arch/riscv/Kconfig > > +++ b/arch/riscv/Kconfig > > @@ -276,6 +276,7 @@ config AS_HAS_OPTION_ARCH > > > > source "arch/riscv/Kconfig.socs" > > source "arch/riscv/Kconfig.errata" > > +source "arch/riscv/Kconfig.vendor" > > > > menu "Platform type" > > > > diff --git a/arch/riscv/Kconfig.vendor b/arch/riscv/Kconfig.vendor > > new file mode 100644 > > index 000000000000..213ac3e6fed5 > > --- /dev/null > > +++ b/arch/riscv/Kconfig.vendor > > @@ -0,0 +1,3 @@ > > +menu "Vendor extensions selection" > > + > > +endmenu # "Vendor extensions selection" > > diff --git a/arch/riscv/include/asm/hwprobe.h > > b/arch/riscv/include/asm/hwprobe.h index 78936f4ff513..fadb38b83243 100644 > > --- a/arch/riscv/include/asm/hwprobe.h > > +++ b/arch/riscv/include/asm/hwprobe.h > > @@ -9,5 +9,6 @@ > > #include <uapi/asm/hwprobe.h> > > > > #define RISCV_HWPROBE_MAX_KEY 5 > > +#define RISCV_HWPROBE_VENDOR_EXTENSION_SPACE (UL(1)<<63) > > Isn't this UB on 32-bit RISC-V ? Hmm, yeah it would be, but the hwprobe syscall is based on a 64 bit key using the __s64 type. There could be an alternative vendor space at the top of 32-bits for those machines. > > > > > #endif > > diff --git a/arch/riscv/kernel/sys_riscv.c b/arch/riscv/kernel/sys_riscv.c > > index 26ef5526bfb4..2351a5f7b8b1 100644 > > --- a/arch/riscv/kernel/sys_riscv.c > > +++ b/arch/riscv/kernel/sys_riscv.c > > @@ -188,9 +188,35 @@ static u64 hwprobe_misaligned(const struct cpumask > > *cpus) return perf; > > } > > > > +static int hwprobe_vendor(__u64 mvendorid, struct riscv_hwprobe *pair, > > + const struct cpumask *cpus) > > +{ > > + switch (mvendorid) { > > + default: > > + return -1; > > + } > > + > > + return 0; > > +} > > + > > static void hwprobe_one_pair(struct riscv_hwprobe *pair, > > const struct cpumask *cpus) > > { > > + int err; > > + > > + if (((unsigned long) pair->key) >= > RISCV_HWPROBE_VENDOR_EXTENSION_SPACE) { > > + struct riscv_hwprobe mvendorid = { > > + .key = RISCV_HWPROBE_KEY_MVENDORID, > > + .value = 0 > > + }; > > + > > + hwprobe_arch_id(&mvendorid, cpus); > > + if (mvendorid.value != -1ULL) > > + err = hwprobe_vendor(mvendorid.value, pair, > cpus); > > + else > > + err = -1; > > + } > > + > > switch (pair->key) { > > case RISCV_HWPROBE_KEY_MVENDORID: > > case RISCV_HWPROBE_KEY_MARCHID: > > @@ -217,13 +243,21 @@ static void hwprobe_one_pair(struct riscv_hwprobe > > *pair, > > > > /* > > * For forward compatibility, unknown keys don't fail the whole > > - * call, but get their element key set to -1 and value set to 0 > > - * indicating they're unrecognized. > > + * call, instead an error is raised to indicate the element key > > + * is unrecognized. > > */ > > default: > > + err = -1; > > + break; > > + } > > + > > + /* > > + * Setting the element key to -1 and value to 0 indicates that > > + * hwprobe was unable to find the requested key. > > + */ > > + if (err != 0) { > > pair->key = -1; > > pair->value = 0; > > - break; > > } > > } > > > > diff --git a/arch/riscv/vendor_extensions/Makefile > > b/arch/riscv/vendor_extensions/Makefile new file mode 100644 > > index 000000000000..e815895e9372 > > --- /dev/null > > +++ b/arch/riscv/vendor_extensions/Makefile > > @@ -0,0 +1,3 @@ > > +ifdef CONFIG_RELOCATABLE > > +KBUILD_CFLAGS += -fno-pie > > +endif > > > -- > レミ・デニ-クールモン > http://www.remlab.net/ > > > > > _______________________________________________ > linux-riscv mailing list > linux-riscv@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-riscv
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