| Message ID | 20230125142056.18356-8-andy.chiu@sifive.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | riscv: Add vector ISA support | expand |
Hey again Andy! On Wed, Jan 25, 2023 at 02:20:44PM +0000, Andy Chiu wrote: > From: Greentime Hu <greentime.hu@sifive.com> > > This patch is used to detect the size of CPU vector registers and use > riscv_vsize to save the size of all the vector registers. It assumes all > harts has the same capabilities in a SMP system. > > [guoren@linux.alibaba.com: add has_vector checking] > Co-developed-by: Guo Ren <guoren@linux.alibaba.com> > Signed-off-by: Guo Ren <guoren@linux.alibaba.com> > Co-developed-by: Vincent Chen <vincent.chen@sifive.com> > Signed-off-by: Vincent Chen <vincent.chen@sifive.com> > Signed-off-by: Greentime Hu <greentime.hu@sifive.com> > Signed-off-by: Andy Chiu <andy.chiu@sifive.com> > --- > arch/riscv/include/asm/vector.h | 3 +++ > arch/riscv/kernel/cpufeature.c | 12 +++++++++++- > 2 files changed, 14 insertions(+), 1 deletion(-) > > diff --git a/arch/riscv/include/asm/vector.h b/arch/riscv/include/asm/vector.h > index 0fda0faf5277..16cb4a1c1230 100644 > --- a/arch/riscv/include/asm/vector.h > +++ b/arch/riscv/include/asm/vector.h > @@ -13,6 +13,8 @@ > #include <asm/hwcap.h> > #include <asm/csr.h> > > +extern unsigned long riscv_vsize; Hmm, naming this with a riscv_v_ prefix too would be good I think. > + > static __always_inline bool has_vector(void) > { > return static_branch_likely(&riscv_isa_ext_keys[RISCV_ISA_EXT_KEY_VECTOR]); > @@ -31,6 +33,7 @@ static __always_inline void rvv_disable(void) > #else /* ! CONFIG_RISCV_ISA_V */ > > static __always_inline bool has_vector(void) { return false; } > +#define riscv_vsize (0) > > #endif /* CONFIG_RISCV_ISA_V */ > > diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c > index c433899542ff..3aaae4e0b963 100644 > --- a/arch/riscv/kernel/cpufeature.c > +++ b/arch/riscv/kernel/cpufeature.c > @@ -21,6 +21,7 @@ > #include <asm/processor.h> > #include <asm/smp.h> > #include <asm/switch_to.h> > +#include <asm/vector.h> > > #define NUM_ALPHA_EXTS ('z' - 'a' + 1) > > @@ -31,6 +32,10 @@ static DECLARE_BITMAP(riscv_isa, RISCV_ISA_EXT_MAX) __read_mostly; > > DEFINE_STATIC_KEY_ARRAY_FALSE(riscv_isa_ext_keys, RISCV_ISA_EXT_KEY_MAX); > EXPORT_SYMBOL(riscv_isa_ext_keys); > +#ifdef CONFIG_RISCV_ISA_V > +unsigned long riscv_vsize __read_mostly; > +EXPORT_SYMBOL_GPL(riscv_vsize); > +#endif I really don't think that this should be in here at all. IMO, this should be moved out to vector.c or something along those lines and... > > /** > * riscv_isa_extension_base() - Get base extension word > @@ -258,7 +263,12 @@ void __init riscv_fill_hwcap(void) > } > > if (elf_hwcap & COMPAT_HWCAP_ISA_V) { > -#ifndef CONFIG_RISCV_ISA_V > +#ifdef CONFIG_RISCV_ISA_V > + /* There are 32 vector registers with vlenb length. */ > + rvv_enable(); > + riscv_vsize = csr_read(CSR_VLENB) * 32; > + rvv_disable(); > +#else ...so should all of this code, especially the csr_read(). vector.c would then provide the actual implementation, and vector.h would provide an implementation with an empty function body. The code here could the, following my previous suggestion of IS_ENABLED() look along the lines of: if (elf_hwcap & COMPAT_HWCAP_ISA_V) { if (IS_ENABLED(CONFIG_RISCV_ISA_V)) riscv_v_setup_vsize(); else elf_hwcap &= ~COMPAT_HWCAP_ISA_V; } Having the csr_read() in particular looks rather out of place to me in this file. Better off keeping the vector stuff together & having unneeded ifdefs is my pet peeve ;) Thanks, Conor.
diff --git a/arch/riscv/include/asm/vector.h b/arch/riscv/include/asm/vector.h index 0fda0faf5277..16cb4a1c1230 100644 --- a/arch/riscv/include/asm/vector.h +++ b/arch/riscv/include/asm/vector.h @@ -13,6 +13,8 @@ #include <asm/hwcap.h> #include <asm/csr.h> +extern unsigned long riscv_vsize; + static __always_inline bool has_vector(void) { return static_branch_likely(&riscv_isa_ext_keys[RISCV_ISA_EXT_KEY_VECTOR]); @@ -31,6 +33,7 @@ static __always_inline void rvv_disable(void) #else /* ! CONFIG_RISCV_ISA_V */ static __always_inline bool has_vector(void) { return false; } +#define riscv_vsize (0) #endif /* CONFIG_RISCV_ISA_V */ diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c index c433899542ff..3aaae4e0b963 100644 --- a/arch/riscv/kernel/cpufeature.c +++ b/arch/riscv/kernel/cpufeature.c @@ -21,6 +21,7 @@ #include <asm/processor.h> #include <asm/smp.h> #include <asm/switch_to.h> +#include <asm/vector.h> #define NUM_ALPHA_EXTS ('z' - 'a' + 1) @@ -31,6 +32,10 @@ static DECLARE_BITMAP(riscv_isa, RISCV_ISA_EXT_MAX) __read_mostly; DEFINE_STATIC_KEY_ARRAY_FALSE(riscv_isa_ext_keys, RISCV_ISA_EXT_KEY_MAX); EXPORT_SYMBOL(riscv_isa_ext_keys); +#ifdef CONFIG_RISCV_ISA_V +unsigned long riscv_vsize __read_mostly; +EXPORT_SYMBOL_GPL(riscv_vsize); +#endif /** * riscv_isa_extension_base() - Get base extension word @@ -258,7 +263,12 @@ void __init riscv_fill_hwcap(void) } if (elf_hwcap & COMPAT_HWCAP_ISA_V) { -#ifndef CONFIG_RISCV_ISA_V +#ifdef CONFIG_RISCV_ISA_V + /* There are 32 vector registers with vlenb length. */ + rvv_enable(); + riscv_vsize = csr_read(CSR_VLENB) * 32; + rvv_disable(); +#else /* * ISA string in device tree might have 'v' flag, but * CONFIG_RISCV_ISA_V is disabled in kernel.