From: Anup Patel <Anup.Patel@wdc.com>
To: Palmer Dabbelt <palmer@dabbelt.com>,
Paul Walmsley <paul.walmsley@sifive.com>,
Albert Ou <aou@eecs.berkeley.edu>,
Paolo Bonzini <pbonzini@redhat.com>, Radim K <rkrcmar@redhat.com>
Cc: Damien Le Moal <Damien.LeMoal@wdc.com>,
"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
Anup Patel <anup@brainfault.org>, Anup Patel <Anup.Patel@wdc.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Atish Patra <Atish.Patra@wdc.com>,
Alistair Francis <Alistair.Francis@wdc.com>,
"kvm-riscv@lists.infradead.org" <kvm-riscv@lists.infradead.org>,
Alexander Graf <graf@amazon.com>,
"linux-riscv@lists.infradead.org"
<linux-riscv@lists.infradead.org>, Christoph Hellwig <hch@lst.de>
Subject: [PATCH v10 02/19] RISC-V: Add bitmap reprensenting ISA features common across CPUs
Date: Mon, 23 Dec 2019 11:35:26 +0000 [thread overview]
Message-ID: <20191223113443.68969-3-anup.patel@wdc.com> (raw)
In-Reply-To: <20191223113443.68969-1-anup.patel@wdc.com>
This patch adds riscv_isa bitmap which represents Host ISA features
common across all Host CPUs. The riscv_isa is not same as elf_hwcap
because elf_hwcap will only have ISA features relevant for user-space
apps whereas riscv_isa will have ISA features relevant to both kernel
and user-space apps.
One of the use-case for riscv_isa bitmap is in KVM hypervisor where
we will use it to do following operations:
1. Check whether hypervisor extension is available
2. Find ISA features that need to be virtualized (e.g. floating
point support, vector extension, etc.)
Signed-off-by: Anup Patel <anup.patel@wdc.com>
Signed-off-by: Atish Patra <atish.patra@wdc.com>
Reviewed-by: Alexander Graf <graf@amazon.com>
---
arch/riscv/include/asm/hwcap.h | 22 +++++++++
arch/riscv/kernel/cpufeature.c | 83 ++++++++++++++++++++++++++++++++--
2 files changed, 102 insertions(+), 3 deletions(-)
diff --git a/arch/riscv/include/asm/hwcap.h b/arch/riscv/include/asm/hwcap.h
index 1bb0cd04aec3..5589c012e004 100644
--- a/arch/riscv/include/asm/hwcap.h
+++ b/arch/riscv/include/asm/hwcap.h
@@ -8,6 +8,7 @@
#ifndef _ASM_RISCV_HWCAP_H
#define _ASM_RISCV_HWCAP_H
+#include <linux/bits.h>
#include <uapi/asm/hwcap.h>
#ifndef __ASSEMBLY__
@@ -22,6 +23,27 @@ enum {
};
extern unsigned long elf_hwcap;
+
+#define RISCV_ISA_EXT_a ('a' - 'a')
+#define RISCV_ISA_EXT_c ('c' - 'a')
+#define RISCV_ISA_EXT_d ('d' - 'a')
+#define RISCV_ISA_EXT_f ('f' - 'a')
+#define RISCV_ISA_EXT_h ('h' - 'a')
+#define RISCV_ISA_EXT_i ('i' - 'a')
+#define RISCV_ISA_EXT_m ('m' - 'a')
+#define RISCV_ISA_EXT_s ('s' - 'a')
+#define RISCV_ISA_EXT_u ('u' - 'a')
+
+#define RISCV_ISA_EXT_MAX 256
+
+unsigned long riscv_isa_extension_base(const unsigned long *isa_bitmap);
+
+#define riscv_isa_extension_mask(ext) BIT_MASK(RISCV_ISA_EXT_##ext)
+
+bool __riscv_isa_extension_available(const unsigned long *isa_bitmap, int bit);
+#define riscv_isa_extension_available(isa_bitmap, ext) \
+ __riscv_isa_extension_available(isa_bitmap, RISCV_ISA_EXT_##ext)
+
#endif
#endif /* _ASM_RISCV_HWCAP_H */
diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c
index 0b40705567b7..e172a2322b34 100644
--- a/arch/riscv/kernel/cpufeature.c
+++ b/arch/riscv/kernel/cpufeature.c
@@ -6,6 +6,7 @@
* Copyright (C) 2017 SiFive
*/
+#include <linux/bitmap.h>
#include <linux/of.h>
#include <asm/processor.h>
#include <asm/hwcap.h>
@@ -13,15 +14,57 @@
#include <asm/switch_to.h>
unsigned long elf_hwcap __read_mostly;
+
+/* Host ISA bitmap */
+static DECLARE_BITMAP(riscv_isa, RISCV_ISA_EXT_MAX) __read_mostly;
+
#ifdef CONFIG_FPU
bool has_fpu __read_mostly;
#endif
+/**
+ * riscv_isa_extension_base() - Get base extension word
+ *
+ * @isa_bitmap: ISA bitmap to use
+ * Return: base extension word as unsigned long value
+ *
+ * NOTE: If isa_bitmap is NULL then Host ISA bitmap will be used.
+ */
+unsigned long riscv_isa_extension_base(const unsigned long *isa_bitmap)
+{
+ if (!isa_bitmap)
+ return riscv_isa[0];
+ return isa_bitmap[0];
+}
+EXPORT_SYMBOL_GPL(riscv_isa_extension_base);
+
+/**
+ * __riscv_isa_extension_available() - Check whether given extension
+ * is available or not
+ *
+ * @isa_bitmap: ISA bitmap to use
+ * @bit: bit position of the desired extension
+ * Return: true or false
+ *
+ * NOTE: If isa_bitmap is NULL then Host ISA bitmap will be used.
+ */
+bool __riscv_isa_extension_available(const unsigned long *isa_bitmap, int bit)
+{
+ const unsigned long *bmap = (isa_bitmap) ? isa_bitmap : riscv_isa;
+
+ if (bit >= RISCV_ISA_EXT_MAX)
+ return false;
+
+ return test_bit(bit, bmap) ? true : false;
+}
+EXPORT_SYMBOL_GPL(__riscv_isa_extension_available);
+
void riscv_fill_hwcap(void)
{
struct device_node *node;
const char *isa;
- size_t i;
+ char print_str[BITS_PER_LONG + 1];
+ size_t i, j, isa_len;
static unsigned long isa2hwcap[256] = {0};
isa2hwcap['i'] = isa2hwcap['I'] = COMPAT_HWCAP_ISA_I;
@@ -33,8 +76,11 @@ void riscv_fill_hwcap(void)
elf_hwcap = 0;
+ bitmap_zero(riscv_isa, RISCV_ISA_EXT_MAX);
+
for_each_of_cpu_node(node) {
unsigned long this_hwcap = 0;
+ unsigned long this_isa = 0;
if (riscv_of_processor_hartid(node) < 0)
continue;
@@ -42,8 +88,24 @@ void riscv_fill_hwcap(void)
if (riscv_read_check_isa(node, &isa) < 0)
continue;
- for (i = 0; i < strlen(isa); ++i)
+ i = 0;
+ isa_len = strlen(isa);
+#if IS_ENABLED(CONFIG_32BIT)
+ if (!strncmp(isa, "rv32", 4))
+ i += 4;
+#elif IS_ENABLED(CONFIG_64BIT)
+ if (!strncmp(isa, "rv64", 4))
+ i += 4;
+#endif
+ for (; i < isa_len; ++i) {
this_hwcap |= isa2hwcap[(unsigned char)(isa[i])];
+ /*
+ * TODO: X, Y and Z extension parsing for Host ISA
+ * bitmap will be added in-future.
+ */
+ if ('a' <= isa[i] && isa[i] < 'x')
+ this_isa |= (1UL << (isa[i] - 'a'));
+ }
/*
* All "okay" hart should have same isa. Set HWCAP based on
@@ -54,6 +116,11 @@ void riscv_fill_hwcap(void)
elf_hwcap &= this_hwcap;
else
elf_hwcap = this_hwcap;
+
+ if (riscv_isa[0])
+ riscv_isa[0] &= this_isa;
+ else
+ riscv_isa[0] = this_isa;
}
/* We don't support systems with F but without D, so mask those out
@@ -63,7 +130,17 @@ void riscv_fill_hwcap(void)
elf_hwcap &= ~COMPAT_HWCAP_ISA_F;
}
- pr_info("elf_hwcap is 0x%lx\n", elf_hwcap);
+ memset(print_str, 0, sizeof(print_str));
+ for (i = 0, j = 0; i < BITS_PER_LONG; i++)
+ if (riscv_isa[0] & BIT_MASK(i))
+ print_str[j++] = (char)('a' + i);
+ pr_info("riscv: ISA extensions %s\n", print_str);
+
+ memset(print_str, 0, sizeof(print_str));
+ for (i = 0, j = 0; i < BITS_PER_LONG; i++)
+ if (elf_hwcap & BIT_MASK(i))
+ print_str[j++] = (char)('a' + i);
+ pr_info("riscv: ELF capabilities %s\n", print_str);
#ifdef CONFIG_FPU
if (elf_hwcap & (COMPAT_HWCAP_ISA_F | COMPAT_HWCAP_ISA_D))
--
2.17.1
next prev parent reply other threads:[~2019-12-23 11:35 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-23 11:35 [PATCH v10 00/19] KVM RISC-V Support Anup Patel
2019-12-23 11:35 ` [PATCH v10 01/19] RISC-V: Export riscv_cpuid_to_hartid_mask() API Anup Patel
2019-12-23 11:35 ` Anup Patel [this message]
2019-12-23 11:35 ` [PATCH v10 03/19] RISC-V: Add hypervisor extension related CSR defines Anup Patel
2019-12-23 11:35 ` [PATCH v10 04/19] RISC-V: Add initial skeletal KVM support Anup Patel
2019-12-23 11:35 ` [PATCH v10 05/19] RISC-V: KVM: Implement VCPU create, init and destroy functions Anup Patel
2019-12-23 11:36 ` [PATCH v10 06/19] RISC-V: KVM: Implement VCPU interrupts and requests handling Anup Patel
2019-12-23 11:36 ` [PATCH v10 07/19] RISC-V: KVM: Implement KVM_GET_ONE_REG/KVM_SET_ONE_REG ioctls Anup Patel
2019-12-23 11:36 ` [PATCH v10 08/19] RISC-V: KVM: Implement VCPU world-switch Anup Patel
2019-12-23 11:36 ` [PATCH v10 09/19] RISC-V: KVM: Handle MMIO exits for VCPU Anup Patel
2019-12-23 11:36 ` [PATCH v10 10/19] RISC-V: KVM: Handle WFI " Anup Patel
2019-12-23 11:36 ` [PATCH v10 11/19] RISC-V: KVM: Implement VMID allocator Anup Patel
2019-12-23 11:36 ` [PATCH v10 12/19] RISC-V: KVM: Implement stage2 page table programming Anup Patel
2019-12-23 11:37 ` [PATCH v10 13/19] RISC-V: KVM: Implement MMU notifiers Anup Patel
2019-12-23 11:37 ` [PATCH v10 14/19] RISC-V: KVM: Add timer functionality Anup Patel
2019-12-23 11:37 ` [PATCH v10 15/19] RISC-V: KVM: FP lazy save/restore Anup Patel
2019-12-23 11:37 ` [PATCH v10 16/19] RISC-V: KVM: Implement ONE REG interface for FP registers Anup Patel
2019-12-23 11:37 ` [PATCH v10 17/19] RISC-V: KVM: Add SBI v0.1 support Anup Patel
2019-12-23 11:37 ` [PATCH v10 18/19] RISC-V: KVM: Document RISC-V specific parts of KVM API Anup Patel
2019-12-23 11:37 ` [PATCH v10 19/19] RISC-V: KVM: Add MAINTAINERS entry Anup Patel
2020-01-16 1:45 ` [PATCH v10 00/19] KVM RISC-V Support Palmer Dabbelt
2020-01-16 16:51 ` [PATCH v10 01/19] RISC-V: Export riscv_cpuid_to_hartid_mask() API Palmer Dabbelt
2020-01-16 19:51 ` [PATCH v10 02/19] RISC-V: Add bitmap reprensenting ISA features common across CPUs Palmer Dabbelt
2020-01-17 6:45 ` Anup Patel
2020-01-16 19:51 ` [PATCH v10 03/19] RISC-V: Add hypervisor extension related CSR defines Palmer Dabbelt
2020-01-17 7:14 ` Anup Patel
2020-01-16 23:37 ` [PATCH v10 04/19] RISC-V: Add initial skeletal KVM support Palmer Dabbelt
2020-01-17 7:11 ` Anup Patel
2020-01-22 19:04 ` [PATCH v10 05/19] RISC-V: KVM: Implement VCPU create, init and destroy functions Palmer Dabbelt
2020-01-23 3:34 ` Anup Patel
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