diff mbox series

[-next,v19,08/24] riscv: Introduce riscv_v_vsize to record size of Vector context

Message ID 20230509103033.11285-9-andy.chiu@sifive.com (mailing list archive)
State New, archived
Headers show
Series riscv: Add vector ISA support | expand

Commit Message

Andy Chiu May 9, 2023, 10:30 a.m. UTC 
From: Greentime Hu <greentime.hu@sifive.com>

This patch is used to detect the size of CPU vector registers and use
riscv_v_vsize to save the size of all the vector registers. It assumes all
harts has the same capabilities in a SMP system. If a core detects VLENB
that is different from the boot core, then it warns and turns off V
support for user space.

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>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Reviewed-by: Heiko Stuebner <heiko.stuebner@vrull.eu>
Tested-by: Heiko Stuebner <heiko.stuebner@vrull.eu>
---
Changelog V19:
 - Fix grammar in WARN() (Conor)
Changelog V18:
 - Detect inconsistent VLEN setup on an SMP system (Heiko).

 arch/riscv/include/asm/vector.h |  8 ++++++++
 arch/riscv/kernel/Makefile      |  1 +
 arch/riscv/kernel/cpufeature.c  |  2 ++
 arch/riscv/kernel/smpboot.c     |  7 +++++++
 arch/riscv/kernel/vector.c      | 36 +++++++++++++++++++++++++++++++++
 5 files changed, 54 insertions(+)
 create mode 100644 arch/riscv/kernel/vector.c

Comments

Palmer Dabbelt May 11, 2023, 10:56 p.m. UTC | #1 
On Tue, 09 May 2023 03:30:17 PDT (-0700), andy.chiu@sifive.com wrote:
> From: Greentime Hu <greentime.hu@sifive.com>
>
> This patch is used to detect the size of CPU vector registers and use
> riscv_v_vsize to save the size of all the vector registers. It assumes all
> harts has the same capabilities in a SMP system. If a core detects VLENB
> that is different from the boot core, then it warns and turns off V
> support for user space.
>
> 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>
> Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
> Reviewed-by: Heiko Stuebner <heiko.stuebner@vrull.eu>
> Tested-by: Heiko Stuebner <heiko.stuebner@vrull.eu>
> ---
> Changelog V19:
>  - Fix grammar in WARN() (Conor)
> Changelog V18:
>  - Detect inconsistent VLEN setup on an SMP system (Heiko).
>
>  arch/riscv/include/asm/vector.h |  8 ++++++++
>  arch/riscv/kernel/Makefile      |  1 +
>  arch/riscv/kernel/cpufeature.c  |  2 ++
>  arch/riscv/kernel/smpboot.c     |  7 +++++++
>  arch/riscv/kernel/vector.c      | 36 +++++++++++++++++++++++++++++++++
>  5 files changed, 54 insertions(+)
>  create mode 100644 arch/riscv/kernel/vector.c
>
> diff --git a/arch/riscv/include/asm/vector.h b/arch/riscv/include/asm/vector.h
> index dfe5a321b2b4..68c9fe831a41 100644
> --- a/arch/riscv/include/asm/vector.h
> +++ b/arch/riscv/include/asm/vector.h
> @@ -7,12 +7,16 @@
>  #define __ASM_RISCV_VECTOR_H
>
>  #include <linux/types.h>
> +#include <uapi/asm-generic/errno.h>
>
>  #ifdef CONFIG_RISCV_ISA_V
>
>  #include <asm/hwcap.h>
>  #include <asm/csr.h>
>
> +extern unsigned long riscv_v_vsize;
> +int riscv_v_setup_vsize(void);
> +
>  static __always_inline bool has_vector(void)
>  {
>  	return riscv_has_extension_likely(RISCV_ISA_EXT_v);
> @@ -30,7 +34,11 @@ static __always_inline void riscv_v_disable(void)
>
>  #else /* ! CONFIG_RISCV_ISA_V  */
>
> +struct pt_regs;
> +
> +static inline int riscv_v_setup_vsize(void) { return -EOPNOTSUPP; }
>  static __always_inline bool has_vector(void) { return false; }
> +#define riscv_v_vsize (0)
>
>  #endif /* CONFIG_RISCV_ISA_V */
>
> diff --git a/arch/riscv/kernel/Makefile b/arch/riscv/kernel/Makefile
> index fbdccc21418a..c51f34c2756a 100644
> --- a/arch/riscv/kernel/Makefile
> +++ b/arch/riscv/kernel/Makefile
> @@ -56,6 +56,7 @@ obj-$(CONFIG_MMU) += vdso.o vdso/
>
>  obj-$(CONFIG_RISCV_M_MODE)	+= traps_misaligned.o
>  obj-$(CONFIG_FPU)		+= fpu.o
> +obj-$(CONFIG_RISCV_ISA_V)	+= vector.o
>  obj-$(CONFIG_SMP)		+= smpboot.o
>  obj-$(CONFIG_SMP)		+= smp.o
>  obj-$(CONFIG_SMP)		+= cpu_ops.o
> diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c
> index 7aaf92fff64e..28032b083463 100644
> --- a/arch/riscv/kernel/cpufeature.c
> +++ b/arch/riscv/kernel/cpufeature.c
> @@ -18,6 +18,7 @@
>  #include <asm/hwcap.h>
>  #include <asm/patch.h>
>  #include <asm/processor.h>
> +#include <asm/vector.h>
>
>  #define NUM_ALPHA_EXTS ('z' - 'a' + 1)
>
> @@ -269,6 +270,7 @@ void __init riscv_fill_hwcap(void)
>  	}
>
>  	if (elf_hwcap & COMPAT_HWCAP_ISA_V) {
> +		riscv_v_setup_vsize();
>  		/*
>  		 * ISA string in device tree might have 'v' flag, but
>  		 * CONFIG_RISCV_ISA_V is disabled in kernel.
> diff --git a/arch/riscv/kernel/smpboot.c b/arch/riscv/kernel/smpboot.c
> index 445a4efee267..66011bf2b36e 100644
> --- a/arch/riscv/kernel/smpboot.c
> +++ b/arch/riscv/kernel/smpboot.c
> @@ -31,6 +31,8 @@
>  #include <asm/tlbflush.h>
>  #include <asm/sections.h>
>  #include <asm/smp.h>
> +#include <uapi/asm/hwcap.h>
> +#include <asm/vector.h>
>
>  #include "head.h"
>
> @@ -169,6 +171,11 @@ asmlinkage __visible void smp_callin(void)
>  	set_cpu_online(curr_cpuid, 1);
>  	probe_vendor_features(curr_cpuid);
>
> +	if (has_vector()) {
> +		if (riscv_v_setup_vsize())
> +			elf_hwcap &= ~COMPAT_HWCAP_ISA_V;
> +	}
> +
>  	/*
>  	 * Remote TLB flushes are ignored while the CPU is offline, so emit
>  	 * a local TLB flush right now just in case.
> diff --git a/arch/riscv/kernel/vector.c b/arch/riscv/kernel/vector.c
> new file mode 100644
> index 000000000000..120f1ce9abf9
> --- /dev/null
> +++ b/arch/riscv/kernel/vector.c
> @@ -0,0 +1,36 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +/*
> + * Copyright (C) 2023 SiFive
> + * Author: Andy Chiu <andy.chiu@sifive.com>
> + */
> +#include <linux/export.h>
> +
> +#include <asm/vector.h>
> +#include <asm/csr.h>
> +#include <asm/elf.h>
> +#include <asm/bug.h>
> +
> +unsigned long riscv_v_vsize __read_mostly;
> +EXPORT_SYMBOL_GPL(riscv_v_vsize);
> +
> +int riscv_v_setup_vsize(void)
> +{
> +	unsigned long this_vsize;
> +
> +	/* There are 32 vector registers with vlenb length. */
> +	riscv_v_enable();
> +	this_vsize = csr_read(CSR_VLENB) * 32;
> +	riscv_v_disable();
> +
> +	if (!riscv_v_vsize) {
> +		riscv_v_vsize = this_vsize;
> +		return 0;
> +	}
> +
> +	if (riscv_v_vsize != this_vsize) {
> +		WARN(1, "RISCV_ISA_V only supports one vlenb on SMP systems");
> +		return -EOPNOTSUPP;
> +	}
> +
> +	return 0;
> +}

Reviewed-by: Palmer Dabbelt <palmer@rivosinc.com>
diff mbox series

Patch

diff --git a/arch/riscv/include/asm/vector.h b/arch/riscv/include/asm/vector.h
index dfe5a321b2b4..68c9fe831a41 100644
--- a/arch/riscv/include/asm/vector.h
+++ b/arch/riscv/include/asm/vector.h
@@ -7,12 +7,16 @@ 
 #define __ASM_RISCV_VECTOR_H
 
 #include <linux/types.h>
+#include <uapi/asm-generic/errno.h>
 
 #ifdef CONFIG_RISCV_ISA_V
 
 #include <asm/hwcap.h>
 #include <asm/csr.h>
 
+extern unsigned long riscv_v_vsize;
+int riscv_v_setup_vsize(void);
+
 static __always_inline bool has_vector(void)
 {
 	return riscv_has_extension_likely(RISCV_ISA_EXT_v);
@@ -30,7 +34,11 @@  static __always_inline void riscv_v_disable(void)
 
 #else /* ! CONFIG_RISCV_ISA_V  */
 
+struct pt_regs;
+
+static inline int riscv_v_setup_vsize(void) { return -EOPNOTSUPP; }
 static __always_inline bool has_vector(void) { return false; }
+#define riscv_v_vsize (0)
 
 #endif /* CONFIG_RISCV_ISA_V */
 
diff --git a/arch/riscv/kernel/Makefile b/arch/riscv/kernel/Makefile
index fbdccc21418a..c51f34c2756a 100644
--- a/arch/riscv/kernel/Makefile
+++ b/arch/riscv/kernel/Makefile
@@ -56,6 +56,7 @@  obj-$(CONFIG_MMU) += vdso.o vdso/
 
 obj-$(CONFIG_RISCV_M_MODE)	+= traps_misaligned.o
 obj-$(CONFIG_FPU)		+= fpu.o
+obj-$(CONFIG_RISCV_ISA_V)	+= vector.o
 obj-$(CONFIG_SMP)		+= smpboot.o
 obj-$(CONFIG_SMP)		+= smp.o
 obj-$(CONFIG_SMP)		+= cpu_ops.o
diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c
index 7aaf92fff64e..28032b083463 100644
--- a/arch/riscv/kernel/cpufeature.c
+++ b/arch/riscv/kernel/cpufeature.c
@@ -18,6 +18,7 @@ 
 #include <asm/hwcap.h>
 #include <asm/patch.h>
 #include <asm/processor.h>
+#include <asm/vector.h>
 
 #define NUM_ALPHA_EXTS ('z' - 'a' + 1)
 
@@ -269,6 +270,7 @@  void __init riscv_fill_hwcap(void)
 	}
 
 	if (elf_hwcap & COMPAT_HWCAP_ISA_V) {
+		riscv_v_setup_vsize();
 		/*
 		 * ISA string in device tree might have 'v' flag, but
 		 * CONFIG_RISCV_ISA_V is disabled in kernel.
diff --git a/arch/riscv/kernel/smpboot.c b/arch/riscv/kernel/smpboot.c
index 445a4efee267..66011bf2b36e 100644
--- a/arch/riscv/kernel/smpboot.c
+++ b/arch/riscv/kernel/smpboot.c
@@ -31,6 +31,8 @@ 
 #include <asm/tlbflush.h>
 #include <asm/sections.h>
 #include <asm/smp.h>
+#include <uapi/asm/hwcap.h>
+#include <asm/vector.h>
 
 #include "head.h"
 
@@ -169,6 +171,11 @@  asmlinkage __visible void smp_callin(void)
 	set_cpu_online(curr_cpuid, 1);
 	probe_vendor_features(curr_cpuid);
 
+	if (has_vector()) {
+		if (riscv_v_setup_vsize())
+			elf_hwcap &= ~COMPAT_HWCAP_ISA_V;
+	}
+
 	/*
 	 * Remote TLB flushes are ignored while the CPU is offline, so emit
 	 * a local TLB flush right now just in case.
diff --git a/arch/riscv/kernel/vector.c b/arch/riscv/kernel/vector.c
new file mode 100644
index 000000000000..120f1ce9abf9
--- /dev/null
+++ b/arch/riscv/kernel/vector.c
@@ -0,0 +1,36 @@ 
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2023 SiFive
+ * Author: Andy Chiu <andy.chiu@sifive.com>
+ */
+#include <linux/export.h>
+
+#include <asm/vector.h>
+#include <asm/csr.h>
+#include <asm/elf.h>
+#include <asm/bug.h>
+
+unsigned long riscv_v_vsize __read_mostly;
+EXPORT_SYMBOL_GPL(riscv_v_vsize);
+
+int riscv_v_setup_vsize(void)
+{
+	unsigned long this_vsize;
+
+	/* There are 32 vector registers with vlenb length. */
+	riscv_v_enable();
+	this_vsize = csr_read(CSR_VLENB) * 32;
+	riscv_v_disable();
+
+	if (!riscv_v_vsize) {
+		riscv_v_vsize = this_vsize;
+		return 0;
+	}
+
+	if (riscv_v_vsize != this_vsize) {
+		WARN(1, "RISCV_ISA_V only supports one vlenb on SMP systems");
+		return -EOPNOTSUPP;
+	}
+
+	return 0;
+}