From: Andrew Jones <ajones@ventanamicro.com>
To: linux-riscv@lists.infradead.org
Cc: paul.walmsley@sifive.com, palmer@dabbelt.com,
aou@eecs.berkeley.edu, evan@rivosinc.com,
conor.dooley@microchip.com, apatel@ventanamicro.com
Subject: [PATCH v2 2/6] RISC-V: Enable cbo.zero in usermode
Date: Wed, 30 Aug 2023 18:49:57 +0200 [thread overview]
Message-ID: <20230830164954.91987-10-ajones@ventanamicro.com> (raw)
In-Reply-To: <20230830164954.91987-8-ajones@ventanamicro.com>
When Zicboz is present, enable its instruction (cbo.zero) in
usermode by setting its respective senvcfg bit. We don't bother
trying to set this bit per-task, which would also require an
interface for tasks to request enabling and/or disabling. Instead,
permanently set the bit for each hart which has the extension when
bringing it online.
Signed-off-by: Andrew Jones <ajones@ventanamicro.com>
---
arch/riscv/include/asm/cpufeature.h | 2 ++
arch/riscv/include/asm/csr.h | 1 +
arch/riscv/include/asm/hwcap.h | 16 ++++++++++++++++
arch/riscv/kernel/cpufeature.c | 6 ++++++
arch/riscv/kernel/setup.c | 4 ++++
arch/riscv/kernel/smpboot.c | 4 ++++
6 files changed, 33 insertions(+)
diff --git a/arch/riscv/include/asm/cpufeature.h b/arch/riscv/include/asm/cpufeature.h
index 23fed53b8815..788fd575c21a 100644
--- a/arch/riscv/include/asm/cpufeature.h
+++ b/arch/riscv/include/asm/cpufeature.h
@@ -30,4 +30,6 @@ DECLARE_PER_CPU(long, misaligned_access_speed);
/* Per-cpu ISA extensions. */
extern struct riscv_isainfo hart_isa[NR_CPUS];
+void riscv_user_isa_enable(void);
+
#endif
diff --git a/arch/riscv/include/asm/csr.h b/arch/riscv/include/asm/csr.h
index 7bac43a3176e..e187e76e3df4 100644
--- a/arch/riscv/include/asm/csr.h
+++ b/arch/riscv/include/asm/csr.h
@@ -273,6 +273,7 @@
#define CSR_SIE 0x104
#define CSR_STVEC 0x105
#define CSR_SCOUNTEREN 0x106
+#define CSR_SENVCFG 0x10a
#define CSR_SSCRATCH 0x140
#define CSR_SEPC 0x141
#define CSR_SCAUSE 0x142
diff --git a/arch/riscv/include/asm/hwcap.h b/arch/riscv/include/asm/hwcap.h
index f041bfa7f6a0..66178dbd0045 100644
--- a/arch/riscv/include/asm/hwcap.h
+++ b/arch/riscv/include/asm/hwcap.h
@@ -66,6 +66,7 @@
#ifndef __ASSEMBLY__
#include <linux/jump_label.h>
+#include <asm/cpufeature.h>
unsigned long riscv_get_elf_hwcap(void);
@@ -130,6 +131,21 @@ riscv_has_extension_unlikely(const unsigned long ext)
return true;
}
+static __always_inline bool riscv_cpu_has_extension_likely(int cpu, const unsigned long ext)
+{
+ if (IS_ENABLED(CONFIG_RISCV_ALTERNATIVE) && riscv_has_extension_likely(ext))
+ return true;
+
+ return __riscv_isa_extension_available(hart_isa[cpu].isa, ext);
+}
+
+static __always_inline bool riscv_cpu_has_extension_unlikely(int cpu, const unsigned long ext)
+{
+ if (IS_ENABLED(CONFIG_RISCV_ALTERNATIVE) && riscv_has_extension_unlikely(ext))
+ return true;
+
+ return __riscv_isa_extension_available(hart_isa[cpu].isa, ext);
+}
#endif
#endif /* _ASM_RISCV_HWCAP_H */
diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c
index 31843e9cc80c..a33cf7c89d9e 100644
--- a/arch/riscv/kernel/cpufeature.c
+++ b/arch/riscv/kernel/cpufeature.c
@@ -391,6 +391,12 @@ unsigned long riscv_get_elf_hwcap(void)
return hwcap;
}
+void riscv_user_isa_enable(void)
+{
+ if (riscv_cpu_has_extension_unlikely(smp_processor_id(), RISCV_ISA_EXT_ZICBOZ))
+ csr_set(CSR_SENVCFG, ENVCFG_CBZE);
+}
+
#ifdef CONFIG_RISCV_ALTERNATIVE
/*
* Alternative patch sites consider 48 bits when determining when to patch
diff --git a/arch/riscv/kernel/setup.c b/arch/riscv/kernel/setup.c
index 971fe776e2f8..2f053f0763a1 100644
--- a/arch/riscv/kernel/setup.c
+++ b/arch/riscv/kernel/setup.c
@@ -25,6 +25,7 @@
#include <asm/acpi.h>
#include <asm/alternative.h>
#include <asm/cacheflush.h>
+#include <asm/cpufeature.h>
#include <asm/cpu_ops.h>
#include <asm/early_ioremap.h>
#include <asm/pgtable.h>
@@ -308,9 +309,12 @@ void __init setup_arch(char **cmdline_p)
riscv_fill_hwcap();
init_rt_signal_env();
apply_boot_alternatives();
+
if (IS_ENABLED(CONFIG_RISCV_ISA_ZICBOM) &&
riscv_isa_extension_available(NULL, ZICBOM))
riscv_noncoherent_supported();
+
+ riscv_user_isa_enable();
}
static int __init topology_init(void)
diff --git a/arch/riscv/kernel/smpboot.c b/arch/riscv/kernel/smpboot.c
index f4d6acb38dd0..502b04abda0b 100644
--- a/arch/riscv/kernel/smpboot.c
+++ b/arch/riscv/kernel/smpboot.c
@@ -25,6 +25,8 @@
#include <linux/of.h>
#include <linux/sched/task_stack.h>
#include <linux/sched/mm.h>
+
+#include <asm/cpufeature.h>
#include <asm/cpu_ops.h>
#include <asm/irq.h>
#include <asm/mmu_context.h>
@@ -252,6 +254,8 @@ asmlinkage __visible void smp_callin(void)
elf_hwcap &= ~COMPAT_HWCAP_ISA_V;
}
+ riscv_user_isa_enable();
+
/*
* Remote TLB flushes are ignored while the CPU is offline, so emit
* a local TLB flush right now just in case.
--
2.41.0
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next prev parent reply other threads:[~2023-08-30 16:50 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-08-30 16:49 [PATCH v2 0/6] RISC-V: Enable cbo.zero in usermode Andrew Jones
2023-08-30 16:49 ` [PATCH v2 1/6] RISC-V: Make zicbom/zicboz errors consistent Andrew Jones
2023-08-30 16:49 ` Andrew Jones [this message]
2023-08-31 16:24 ` [PATCH v2 2/6] RISC-V: Enable cbo.zero in usermode Conor Dooley
2023-08-31 16:39 ` Andrew Jones
2023-08-31 16:46 ` Conor Dooley
2023-08-30 16:49 ` [PATCH v2 3/6] RISC-V: hwprobe: Expose Zicboz extension and its block size Andrew Jones
2023-08-31 16:19 ` Conor Dooley
2023-08-30 16:49 ` [PATCH v2 4/6] RISC-V: selftests: Statically link hwprobe test Andrew Jones
2023-08-30 16:50 ` [PATCH v2 5/6] RISC-V: selftests: Convert hwprobe test to kselftest API Andrew Jones
2023-08-30 16:50 ` [PATCH v2 6/6] RISC-V: selftests: Add CBO tests Andrew Jones
2023-09-01 9:37 ` Wang, Xiao W
2023-09-01 15:12 ` Andrew Jones
2023-08-30 16:52 ` [PATCH v2 0/6] RISC-V: Enable cbo.zero in usermode Andrew Jones
2023-08-30 20:28 ` Palmer Dabbelt
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