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Subject[PATCH 2/2] riscv: Add vector ISA support
Date
From: Guo Ren <ren_guo@c-sky.com>

The implementation follow the RISC-V "V" Vector Extension draft v0.8 with
128bit-vlen and it's based on linux-5.5-rc4.

The patch implement basic context switch, signal and ptrace interface
with a new regset NT_RISCV_VECTOR. Only fixed 128bit-vlen is implemented.
We need to discuss about the abi for libc sigcontext. (The maximum size of
vlen for libc signal context structure 128/256/512 ?)

Signed-off-by: Guo Ren <ren_guo@c-sky.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Albert Ou <aou@eecs.berkeley.edu>
---
arch/riscv/Kconfig | 9 ++
arch/riscv/Makefile | 19 ++-
arch/riscv/include/asm/csr.h | 17 +-
arch/riscv/include/asm/processor.h | 1 +
arch/riscv/include/asm/switch_to.h | 54 ++++++-
arch/riscv/include/uapi/asm/elf.h | 1 +
arch/riscv/include/uapi/asm/hwcap.h | 1 +
arch/riscv/include/uapi/asm/ptrace.h | 9 ++
arch/riscv/include/uapi/asm/sigcontext.h | 1 +
arch/riscv/kernel/Makefile | 1 +
arch/riscv/kernel/asm-offsets.c | 190 +++++++++++++++++++++++
arch/riscv/kernel/cpufeature.c | 12 +-
arch/riscv/kernel/entry.S | 2 +-
arch/riscv/kernel/head.S | 49 +++++-
arch/riscv/kernel/process.c | 10 ++
arch/riscv/kernel/ptrace.c | 41 +++++
arch/riscv/kernel/signal.c | 40 +++++
arch/riscv/kernel/vector.S | 84 ++++++++++
include/uapi/linux/elf.h | 1 +
19 files changed, 527 insertions(+), 15 deletions(-)
create mode 100644 arch/riscv/kernel/vector.S

diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index d8efbaa78d67..3d336f869ffe 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -286,6 +286,15 @@ config FPU

If you don't know what to do here, say Y.

+config VECTOR
+ bool "VECTOR support"
+ default n
+ help
+ Say N here if you want to disable all vecotr related procedure
+ in the kernel.
+
+ If you don't know what to do here, say Y.
+
endmenu

menu "Kernel features"
diff --git a/arch/riscv/Makefile b/arch/riscv/Makefile
index b9009a2fbaf5..071eb1148e01 100644
--- a/arch/riscv/Makefile
+++ b/arch/riscv/Makefile
@@ -35,12 +35,19 @@ else
endif

# ISA string setting
-riscv-march-$(CONFIG_ARCH_RV32I) := rv32ima
-riscv-march-$(CONFIG_ARCH_RV64I) := rv64ima
-riscv-march-$(CONFIG_FPU) := $(riscv-march-y)fd
-riscv-march-$(CONFIG_RISCV_ISA_C) := $(riscv-march-y)c
-KBUILD_CFLAGS += -march=$(subst fd,,$(riscv-march-y))
-KBUILD_AFLAGS += -march=$(riscv-march-y)
+riscv-march-cflags-$(CONFIG_ARCH_RV32I) := rv32ima
+riscv-march-cflags-$(CONFIG_ARCH_RV64I) := rv64ima
+riscv-march-$(CONFIG_FPU) := $(riscv-march-y)fd
+riscv-march-cflags-$(CONFIG_RISCV_ISA_C) := $(riscv-march-cflags-y)c
+
+riscv-march-aflags-$(CONFIG_ARCH_RV32I) := rv32ima
+riscv-march-aflags-$(CONFIG_ARCH_RV64I) := rv64ima
+riscv-march-aflags-$(CONFIG_FPU) := $(riscv-march-aflags-y)fd
+riscv-march-aflags-$(CONFIG_RISCV_ISA_C) := $(riscv-march-aflags-y)c
+riscv-march-aflags-$(CONFIG_VECTOR) := $(riscv-march-aflags-y)v
+
+KBUILD_CFLAGS += -march=$(riscv-march-cflags-y)
+KBUILD_AFLAGS += -march=$(riscv-march-aflags-y)

KBUILD_CFLAGS += -mno-save-restore
KBUILD_CFLAGS += -DCONFIG_PAGE_OFFSET=$(CONFIG_PAGE_OFFSET)
diff --git a/arch/riscv/include/asm/csr.h b/arch/riscv/include/asm/csr.h
index 0a62d2d68455..8438ee8d51ff 100644
--- a/arch/riscv/include/asm/csr.h
+++ b/arch/riscv/include/asm/csr.h
@@ -24,6 +24,12 @@
#define SR_FS_CLEAN _AC(0x00004000, UL)
#define SR_FS_DIRTY _AC(0x00006000, UL)

+#define SR_VS _AC(0x01800000, UL) /* Vector Status */
+#define SR_VS_OFF _AC(0x00000000, UL)
+#define SR_VS_INITIAL _AC(0x00800000, UL)
+#define SR_VS_CLEAN _AC(0x01000000, UL)
+#define SR_VS_DIRTY _AC(0x01800000, UL)
+
#define SR_XS _AC(0x00018000, UL) /* Extension Status */
#define SR_XS_OFF _AC(0x00000000, UL)
#define SR_XS_INITIAL _AC(0x00008000, UL)
@@ -31,9 +37,9 @@
#define SR_XS_DIRTY _AC(0x00018000, UL)

#ifndef CONFIG_64BIT
-#define SR_SD _AC(0x80000000, UL) /* FS/XS dirty */
+#define SR_SD _AC(0x80000000, UL) /* FS/VS/XS dirty */
#else
-#define SR_SD _AC(0x8000000000000000, UL) /* FS/XS dirty */
+#define SR_SD _AC(0x8000000000000000, UL) /* FS/VS/XS dirty */
#endif

/* SATP flags */
@@ -102,6 +108,13 @@
#define CSR_MIP 0x344
#define CSR_MHARTID 0xf14

+#define CSR_VSTART 0x8
+#define CSR_VXSAT 0x9
+#define CSR_VXRM 0xa
+#define CSR_VL 0xc20
+#define CSR_VTYPE 0xc21
+#define CSR_VLENB 0xc22
+
#ifdef CONFIG_RISCV_M_MODE
# define CSR_STATUS CSR_MSTATUS
# define CSR_IE CSR_MIE
diff --git a/arch/riscv/include/asm/processor.h b/arch/riscv/include/asm/processor.h
index 3ddb798264f1..217273375cfb 100644
--- a/arch/riscv/include/asm/processor.h
+++ b/arch/riscv/include/asm/processor.h
@@ -32,6 +32,7 @@ struct thread_struct {
unsigned long sp; /* Kernel mode stack */
unsigned long s[12]; /* s[0]: frame pointer */
struct __riscv_d_ext_state fstate;
+ struct __riscv_v_state vstate;
};

#define INIT_THREAD { \
diff --git a/arch/riscv/include/asm/switch_to.h b/arch/riscv/include/asm/switch_to.h
index 407bcc96a710..6e1c7fa599be 100644
--- a/arch/riscv/include/asm/switch_to.h
+++ b/arch/riscv/include/asm/switch_to.h
@@ -44,7 +44,7 @@ static inline void fstate_restore(struct task_struct *task,
}
}

-static inline void __switch_to_aux(struct task_struct *prev,
+static inline void __switch_to_fpu(struct task_struct *prev,
struct task_struct *next)
{
struct pt_regs *regs;
@@ -60,7 +60,53 @@ extern bool has_fpu;
#define has_fpu false
#define fstate_save(task, regs) do { } while (0)
#define fstate_restore(task, regs) do { } while (0)
-#define __switch_to_aux(__prev, __next) do { } while (0)
+#define __switch_to_fpu(__prev, __next) do { } while (0)
+#endif
+
+#ifdef CONFIG_VECTOR
+extern void __vstate_save(struct task_struct *save_to);
+extern void __vstate_restore(struct task_struct *restore_from);
+
+static inline void __vstate_clean(struct pt_regs *regs)
+{
+ regs->status |= (regs->status & ~(SR_VS)) | SR_VS_CLEAN;
+}
+
+static inline void vstate_save(struct task_struct *task,
+ struct pt_regs *regs)
+{
+ if ((regs->status & SR_VS) == SR_VS_DIRTY) {
+ __vstate_save(task);
+ __vstate_clean(regs);
+ }
+}
+
+static inline void vstate_restore(struct task_struct *task,
+ struct pt_regs *regs)
+{
+ if ((regs->status & SR_VS) != SR_VS_OFF) {
+ __vstate_restore(task);
+ __vstate_clean(regs);
+ }
+}
+
+static inline void __switch_to_vector(struct task_struct *prev,
+ struct task_struct *next)
+{
+ struct pt_regs *regs;
+
+ regs = task_pt_regs(prev);
+ if (unlikely(regs->status & SR_SD))
+ vstate_save(prev, regs);
+ vstate_restore(next, task_pt_regs(next));
+}
+
+extern bool has_vector;
+#else
+#define has_vector false
+#define vstate_save(task, regs) do { } while (0)
+#define vstate_restore(task, regs) do { } while (0)
+#define __switch_to_vector(__prev, __next) do { } while (0)
#endif

extern struct task_struct *__switch_to(struct task_struct *,
@@ -71,7 +117,9 @@ do { \
struct task_struct *__prev = (prev); \
struct task_struct *__next = (next); \
if (has_fpu) \
- __switch_to_aux(__prev, __next); \
+ __switch_to_fpu(__prev, __next); \
+ if (has_vector) \
+ __switch_to_vector(__prev, __next); \
((last) = __switch_to(__prev, __next)); \
} while (0)

diff --git a/arch/riscv/include/uapi/asm/elf.h b/arch/riscv/include/uapi/asm/elf.h
index d696d6610231..099434d075a7 100644
--- a/arch/riscv/include/uapi/asm/elf.h
+++ b/arch/riscv/include/uapi/asm/elf.h
@@ -23,6 +23,7 @@ typedef struct user_regs_struct elf_gregset_t;
typedef __u64 elf_fpreg_t;
typedef union __riscv_fp_state elf_fpregset_t;
#define ELF_NFPREG (sizeof(struct __riscv_d_ext_state) / sizeof(elf_fpreg_t))
+#define ELF_NVREG (sizeof(struct __riscv_v_state) / sizeof(elf_greg_t))

#if __riscv_xlen == 64
#define ELF_RISCV_R_SYM(r_info) ELF64_R_SYM(r_info)
diff --git a/arch/riscv/include/uapi/asm/hwcap.h b/arch/riscv/include/uapi/asm/hwcap.h
index dee98ee28318..a913e9a38819 100644
--- a/arch/riscv/include/uapi/asm/hwcap.h
+++ b/arch/riscv/include/uapi/asm/hwcap.h
@@ -21,5 +21,6 @@
#define COMPAT_HWCAP_ISA_F (1 << ('F' - 'A'))
#define COMPAT_HWCAP_ISA_D (1 << ('D' - 'A'))
#define COMPAT_HWCAP_ISA_C (1 << ('C' - 'A'))
+#define COMPAT_HWCAP_ISA_V (1 << ('V' - 'A'))

#endif /* _UAPI_ASM_RISCV_HWCAP_H */
diff --git a/arch/riscv/include/uapi/asm/ptrace.h b/arch/riscv/include/uapi/asm/ptrace.h
index 882547f6bd5c..d913e8949b87 100644
--- a/arch/riscv/include/uapi/asm/ptrace.h
+++ b/arch/riscv/include/uapi/asm/ptrace.h
@@ -71,6 +71,15 @@ struct __riscv_q_ext_state {
__u32 reserved[3];
};

+struct __riscv_v_state {
+ __uint128_t v[32];
+ unsigned long vstart;
+ unsigned long vxsat;
+ unsigned long vxrm;
+ unsigned long vl;
+ unsigned long vtype;
+};
+
union __riscv_fp_state {
struct __riscv_f_ext_state f;
struct __riscv_d_ext_state d;
diff --git a/arch/riscv/include/uapi/asm/sigcontext.h b/arch/riscv/include/uapi/asm/sigcontext.h
index 84f2dfcfdbce..f74b3c814423 100644
--- a/arch/riscv/include/uapi/asm/sigcontext.h
+++ b/arch/riscv/include/uapi/asm/sigcontext.h
@@ -17,6 +17,7 @@
struct sigcontext {
struct user_regs_struct sc_regs;
union __riscv_fp_state sc_fpregs;
+ struct __riscv_v_state sc_vregs;
};

#endif /* _UAPI_ASM_RISCV_SIGCONTEXT_H */
diff --git a/arch/riscv/kernel/Makefile b/arch/riscv/kernel/Makefile
index f40205cb9a22..e5276c3bdffc 100644
--- a/arch/riscv/kernel/Makefile
+++ b/arch/riscv/kernel/Makefile
@@ -30,6 +30,7 @@ obj-$(CONFIG_MMU) += vdso.o vdso/

obj-$(CONFIG_RISCV_M_MODE) += clint.o
obj-$(CONFIG_FPU) += fpu.o
+obj-$(CONFIG_VECTOR) += vector.o
obj-$(CONFIG_SMP) += smpboot.o
obj-$(CONFIG_SMP) += smp.o
obj-$(CONFIG_MODULES) += module.o
diff --git a/arch/riscv/kernel/asm-offsets.c b/arch/riscv/kernel/asm-offsets.c
index 07cb9c10de4e..3332dc69d809 100644
--- a/arch/riscv/kernel/asm-offsets.c
+++ b/arch/riscv/kernel/asm-offsets.c
@@ -70,6 +70,45 @@ void asm_offsets(void)
OFFSET(TASK_THREAD_F31, task_struct, thread.fstate.f[31]);
OFFSET(TASK_THREAD_FCSR, task_struct, thread.fstate.fcsr);

+ OFFSET(TASK_THREAD_V0, task_struct, thread.vstate.v[0]);
+ OFFSET(TASK_THREAD_V1, task_struct, thread.vstate.v[1]);
+ OFFSET(TASK_THREAD_V2, task_struct, thread.vstate.v[2]);
+ OFFSET(TASK_THREAD_V3, task_struct, thread.vstate.v[3]);
+ OFFSET(TASK_THREAD_V4, task_struct, thread.vstate.v[4]);
+ OFFSET(TASK_THREAD_V5, task_struct, thread.vstate.v[5]);
+ OFFSET(TASK_THREAD_V6, task_struct, thread.vstate.v[6]);
+ OFFSET(TASK_THREAD_V7, task_struct, thread.vstate.v[7]);
+ OFFSET(TASK_THREAD_V8, task_struct, thread.vstate.v[8]);
+ OFFSET(TASK_THREAD_V9, task_struct, thread.vstate.v[9]);
+ OFFSET(TASK_THREAD_V10, task_struct, thread.vstate.v[10]);
+ OFFSET(TASK_THREAD_V11, task_struct, thread.vstate.v[11]);
+ OFFSET(TASK_THREAD_V12, task_struct, thread.vstate.v[12]);
+ OFFSET(TASK_THREAD_V13, task_struct, thread.vstate.v[13]);
+ OFFSET(TASK_THREAD_V14, task_struct, thread.vstate.v[14]);
+ OFFSET(TASK_THREAD_V15, task_struct, thread.vstate.v[15]);
+ OFFSET(TASK_THREAD_V16, task_struct, thread.vstate.v[16]);
+ OFFSET(TASK_THREAD_V17, task_struct, thread.vstate.v[17]);
+ OFFSET(TASK_THREAD_V18, task_struct, thread.vstate.v[18]);
+ OFFSET(TASK_THREAD_V19, task_struct, thread.vstate.v[19]);
+ OFFSET(TASK_THREAD_V20, task_struct, thread.vstate.v[20]);
+ OFFSET(TASK_THREAD_V21, task_struct, thread.vstate.v[21]);
+ OFFSET(TASK_THREAD_V22, task_struct, thread.vstate.v[22]);
+ OFFSET(TASK_THREAD_V23, task_struct, thread.vstate.v[23]);
+ OFFSET(TASK_THREAD_V24, task_struct, thread.vstate.v[24]);
+ OFFSET(TASK_THREAD_V25, task_struct, thread.vstate.v[25]);
+ OFFSET(TASK_THREAD_V26, task_struct, thread.vstate.v[26]);
+ OFFSET(TASK_THREAD_V27, task_struct, thread.vstate.v[27]);
+ OFFSET(TASK_THREAD_V28, task_struct, thread.vstate.v[28]);
+ OFFSET(TASK_THREAD_V29, task_struct, thread.vstate.v[29]);
+ OFFSET(TASK_THREAD_V30, task_struct, thread.vstate.v[30]);
+ OFFSET(TASK_THREAD_V31, task_struct, thread.vstate.v[31]);
+ OFFSET(TASK_THREAD_VSTART, task_struct, thread.vstate.vstart);
+ OFFSET(TASK_THREAD_VXSAT, task_struct, thread.vstate.vxsat);
+ OFFSET(TASK_THREAD_VXRM, task_struct, thread.vstate.vxrm);
+ OFFSET(TASK_THREAD_VL, task_struct, thread.vstate.vl);
+ OFFSET(TASK_THREAD_VTYPE, task_struct, thread.vstate.vtype);
+ DEFINE(RISCV_VECTOR_VLENB, sizeof(__uint128_t));
+
DEFINE(PT_SIZE, sizeof(struct pt_regs));
OFFSET(PT_EPC, pt_regs, epc);
OFFSET(PT_RA, pt_regs, ra);
@@ -171,6 +210,7 @@ void asm_offsets(void)
- offsetof(struct task_struct, thread.ra)
);

+ /* Float Point */
DEFINE(TASK_THREAD_F0_F0,
offsetof(struct task_struct, thread.fstate.f[0])
- offsetof(struct task_struct, thread.fstate.f[0])
@@ -304,6 +344,156 @@ void asm_offsets(void)
- offsetof(struct task_struct, thread.fstate.f[0])
);

+ /* Vector */
+ DEFINE(TASK_THREAD_V0_V0,
+ offsetof(struct task_struct, thread.vstate.v[0])
+ - offsetof(struct task_struct, thread.vstate.v[0])
+ );
+ DEFINE(TASK_THREAD_V1_V0,
+ offsetof(struct task_struct, thread.vstate.v[1])
+ - offsetof(struct task_struct, thread.vstate.v[0])
+ );
+ DEFINE(TASK_THREAD_V2_V0,
+ offsetof(struct task_struct, thread.vstate.v[2])
+ - offsetof(struct task_struct, thread.vstate.v[0])
+ );
+ DEFINE(TASK_THREAD_V3_V0,
+ offsetof(struct task_struct, thread.vstate.v[3])
+ - offsetof(struct task_struct, thread.vstate.v[0])
+ );
+ DEFINE(TASK_THREAD_V4_V0,
+ offsetof(struct task_struct, thread.vstate.v[4])
+ - offsetof(struct task_struct, thread.vstate.v[0])
+ );
+ DEFINE(TASK_THREAD_V5_V0,
+ offsetof(struct task_struct, thread.vstate.v[5])
+ - offsetof(struct task_struct, thread.vstate.v[0])
+ );
+ DEFINE(TASK_THREAD_V6_V0,
+ offsetof(struct task_struct, thread.vstate.v[6])
+ - offsetof(struct task_struct, thread.vstate.v[0])
+ );
+ DEFINE(TASK_THREAD_V7_V0,
+ offsetof(struct task_struct, thread.vstate.v[7])
+ - offsetof(struct task_struct, thread.vstate.v[0])
+ );
+ DEFINE(TASK_THREAD_V8_V0,
+ offsetof(struct task_struct, thread.vstate.v[8])
+ - offsetof(struct task_struct, thread.vstate.v[0])
+ );
+ DEFINE(TASK_THREAD_V9_V0,
+ offsetof(struct task_struct, thread.vstate.v[9])
+ - offsetof(struct task_struct, thread.vstate.v[0])
+ );
+ DEFINE(TASK_THREAD_V10_V0,
+ offsetof(struct task_struct, thread.vstate.v[10])
+ - offsetof(struct task_struct, thread.vstate.v[0])
+ );
+ DEFINE(TASK_THREAD_V11_V0,
+ offsetof(struct task_struct, thread.vstate.v[11])
+ - offsetof(struct task_struct, thread.vstate.v[0])
+ );
+ DEFINE(TASK_THREAD_V12_V0,
+ offsetof(struct task_struct, thread.vstate.v[12])
+ - offsetof(struct task_struct, thread.vstate.v[0])
+ );
+ DEFINE(TASK_THREAD_V13_V0,
+ offsetof(struct task_struct, thread.vstate.v[13])
+ - offsetof(struct task_struct, thread.vstate.v[0])
+ );
+ DEFINE(TASK_THREAD_V14_V0,
+ offsetof(struct task_struct, thread.vstate.v[14])
+ - offsetof(struct task_struct, thread.vstate.v[0])
+ );
+ DEFINE(TASK_THREAD_V15_V0,
+ offsetof(struct task_struct, thread.vstate.v[15])
+ - offsetof(struct task_struct, thread.vstate.v[0])
+ );
+ DEFINE(TASK_THREAD_V16_V0,
+ offsetof(struct task_struct, thread.vstate.v[16])
+ - offsetof(struct task_struct, thread.vstate.v[0])
+ );
+ DEFINE(TASK_THREAD_V17_V0,
+ offsetof(struct task_struct, thread.vstate.v[17])
+ - offsetof(struct task_struct, thread.vstate.v[0])
+ );
+ DEFINE(TASK_THREAD_V18_V0,
+ offsetof(struct task_struct, thread.vstate.v[18])
+ - offsetof(struct task_struct, thread.vstate.v[0])
+ );
+ DEFINE(TASK_THREAD_V19_V0,
+ offsetof(struct task_struct, thread.vstate.v[19])
+ - offsetof(struct task_struct, thread.vstate.v[0])
+ );
+ DEFINE(TASK_THREAD_V20_V0,
+ offsetof(struct task_struct, thread.vstate.v[20])
+ - offsetof(struct task_struct, thread.vstate.v[0])
+ );
+ DEFINE(TASK_THREAD_V21_V0,
+ offsetof(struct task_struct, thread.vstate.v[21])
+ - offsetof(struct task_struct, thread.vstate.v[0])
+ );
+ DEFINE(TASK_THREAD_V22_V0,
+ offsetof(struct task_struct, thread.vstate.v[22])
+ - offsetof(struct task_struct, thread.vstate.v[0])
+ );
+ DEFINE(TASK_THREAD_V23_V0,
+ offsetof(struct task_struct, thread.vstate.v[23])
+ - offsetof(struct task_struct, thread.vstate.v[0])
+ );
+ DEFINE(TASK_THREAD_V24_V0,
+ offsetof(struct task_struct, thread.vstate.v[24])
+ - offsetof(struct task_struct, thread.vstate.v[0])
+ );
+ DEFINE(TASK_THREAD_V25_V0,
+ offsetof(struct task_struct, thread.vstate.v[25])
+ - offsetof(struct task_struct, thread.vstate.v[0])
+ );
+ DEFINE(TASK_THREAD_V26_V0,
+ offsetof(struct task_struct, thread.vstate.v[26])
+ - offsetof(struct task_struct, thread.vstate.v[0])
+ );
+ DEFINE(TASK_THREAD_V27_V0,
+ offsetof(struct task_struct, thread.vstate.v[27])
+ - offsetof(struct task_struct, thread.vstate.v[0])
+ );
+ DEFINE(TASK_THREAD_V28_V0,
+ offsetof(struct task_struct, thread.vstate.v[28])
+ - offsetof(struct task_struct, thread.vstate.v[0])
+ );
+ DEFINE(TASK_THREAD_V29_V0,
+ offsetof(struct task_struct, thread.vstate.v[29])
+ - offsetof(struct task_struct, thread.vstate.v[0])
+ );
+ DEFINE(TASK_THREAD_V30_V0,
+ offsetof(struct task_struct, thread.vstate.v[30])
+ - offsetof(struct task_struct, thread.vstate.v[0])
+ );
+ DEFINE(TASK_THREAD_V31_V0,
+ offsetof(struct task_struct, thread.vstate.v[31])
+ - offsetof(struct task_struct, thread.vstate.v[0])
+ );
+ DEFINE(TASK_THREAD_VSTART_V0,
+ offsetof(struct task_struct, thread.vstate.vstart)
+ - offsetof(struct task_struct, thread.vstate.v[0])
+ );
+ DEFINE(TASK_THREAD_VXSAT_V0,
+ offsetof(struct task_struct, thread.vstate.vxsat)
+ - offsetof(struct task_struct, thread.vstate.v[0])
+ );
+ DEFINE(TASK_THREAD_VXRM_V0,
+ offsetof(struct task_struct, thread.vstate.vxrm)
+ - offsetof(struct task_struct, thread.vstate.v[0])
+ );
+ DEFINE(TASK_THREAD_VL_V0,
+ offsetof(struct task_struct, thread.vstate.vl)
+ - offsetof(struct task_struct, thread.vstate.v[0])
+ );
+ DEFINE(TASK_THREAD_VTYPE_V0,
+ offsetof(struct task_struct, thread.vstate.vtype)
+ - offsetof(struct task_struct, thread.vstate.v[0])
+ );
+
/*
* We allocate a pt_regs on the stack when entering the kernel. This
* ensures the alignment is sane.
diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c
index a5ad00043104..c9ab24e3c79e 100644
--- a/arch/riscv/kernel/cpufeature.c
+++ b/arch/riscv/kernel/cpufeature.c
@@ -16,6 +16,9 @@ unsigned long elf_hwcap __read_mostly;
#ifdef CONFIG_FPU
bool has_fpu __read_mostly;
#endif
+#ifdef CONFIG_VECTOR
+bool has_vector __read_mostly;
+#endif

void riscv_fill_hwcap(void)
{
@@ -30,6 +33,7 @@ void riscv_fill_hwcap(void)
isa2hwcap['f'] = isa2hwcap['F'] = COMPAT_HWCAP_ISA_F;
isa2hwcap['d'] = isa2hwcap['D'] = COMPAT_HWCAP_ISA_D;
isa2hwcap['c'] = isa2hwcap['C'] = COMPAT_HWCAP_ISA_C;
+ isa2hwcap['v'] = isa2hwcap['V'] = COMPAT_HWCAP_ISA_V;

elf_hwcap = 0;

@@ -44,7 +48,8 @@ void riscv_fill_hwcap(void)
continue;
}

- for (i = 0; i < strlen(isa); ++i)
+ /* Skip rv64/rv32 to support v/V:vector */
+ for (i = 4; i < strlen(isa); ++i)
this_hwcap |= isa2hwcap[(unsigned char)(isa[i])];

/*
@@ -71,4 +76,9 @@ void riscv_fill_hwcap(void)
if (elf_hwcap & (COMPAT_HWCAP_ISA_F | COMPAT_HWCAP_ISA_D))
has_fpu = true;
#endif
+
+#ifdef CONFIG_VECTOR
+ if (elf_hwcap & COMPAT_HWCAP_ISA_V)
+ has_vector = true;
+#endif
}
diff --git a/arch/riscv/kernel/entry.S b/arch/riscv/kernel/entry.S
index e163b7b64c86..828f0ebce4b5 100644
--- a/arch/riscv/kernel/entry.S
+++ b/arch/riscv/kernel/entry.S
@@ -76,7 +76,7 @@ _save_context:
* Disable the FPU to detect illegal usage of floating point in kernel
* space.
*/
- li t0, SR_SUM | SR_FS
+ li t0, SR_SUM | SR_FS | SR_VS

REG_L s0, TASK_TI_USER_SP(tp)
csrrc s1, CSR_STATUS, t0
diff --git a/arch/riscv/kernel/head.S b/arch/riscv/kernel/head.S
index 2227db63f895..fab03292284e 100644
--- a/arch/riscv/kernel/head.S
+++ b/arch/riscv/kernel/head.S
@@ -72,10 +72,10 @@ _start_kernel:
.option pop

/*
- * Disable FPU to detect illegal usage of
+ * Disable FPU & VECTOR to detect illegal usage of
* floating point in kernel space
*/
- li t0, SR_FS
+ li t0, SR_FS | SR_VS
csrc CSR_STATUS, t0

#ifdef CONFIG_SMP
@@ -290,6 +290,51 @@ ENTRY(reset_regs)
csrw fcsr, 0
/* note that the caller must clear SR_FS */
#endif /* CONFIG_FPU */
+
+#ifdef CONFIG_VECTOR
+ csrr t0, CSR_MISA
+ li t1, (COMPAT_HWCAP_ISA_V >> 16)
+ slli t1, t1, 16
+ and t0, t0, t1
+ beqz t0, .Lreset_regs_done
+
+ li t1, SR_VS
+ csrs CSR_STATUS, t1
+ vmv.v.i v0, 0
+ vmv.v.i v1, 0
+ vmv.v.i v2, 0
+ vmv.v.i v3, 0
+ vmv.v.i v4, 0
+ vmv.v.i v5, 0
+ vmv.v.i v6, 0
+ vmv.v.i v7, 0
+ vmv.v.i v8, 0
+ vmv.v.i v9, 0
+ vmv.v.i v10, 0
+ vmv.v.i v11, 0
+ vmv.v.i v12, 0
+ vmv.v.i v13, 0
+ vmv.v.i v14, 0
+ vmv.v.i v15, 0
+ vmv.v.i v16, 0
+ vmv.v.i v17, 0
+ vmv.v.i v18, 0
+ vmv.v.i v19, 0
+ vmv.v.i v20, 0
+ vmv.v.i v21, 0
+ vmv.v.i v22, 0
+ vmv.v.i v23, 0
+ vmv.v.i v24, 0
+ vmv.v.i v25, 0
+ vmv.v.i v26, 0
+ vmv.v.i v27, 0
+ vmv.v.i v28, 0
+ vmv.v.i v29, 0
+ vmv.v.i v30, 0
+ vmv.v.i v31, 0
+ /* note that the caller must clear SR_VS */
+#endif /* CONFIG_VECTOR */
+
.Lreset_regs_done:
ret
END(reset_regs)
diff --git a/arch/riscv/kernel/process.c b/arch/riscv/kernel/process.c
index 95a3031e5c7c..3665f8c1a2c1 100644
--- a/arch/riscv/kernel/process.c
+++ b/arch/riscv/kernel/process.c
@@ -74,6 +74,16 @@ void start_thread(struct pt_regs *regs, unsigned long pc,
*/
fstate_restore(current, regs);
}
+
+ if (has_vector) {
+ regs->status |= SR_VS_INITIAL;
+ /*
+ * Restore the initial value to the vector register
+ * before starting the user program.
+ */
+ vstate_restore(current, regs);
+ }
+
regs->epc = pc;
regs->sp = sp;
set_fs(USER_DS);
diff --git a/arch/riscv/kernel/ptrace.c b/arch/riscv/kernel/ptrace.c
index 407464201b91..0e3c3543476c 100644
--- a/arch/riscv/kernel/ptrace.c
+++ b/arch/riscv/kernel/ptrace.c
@@ -26,6 +26,9 @@ enum riscv_regset {
#ifdef CONFIG_FPU
REGSET_F,
#endif
+#ifdef CONFIG_VECTOR
+ REGSET_V,
+#endif
};

static int riscv_gpr_get(struct task_struct *target,
@@ -92,6 +95,34 @@ static int riscv_fpr_set(struct task_struct *target,
}
#endif

+#ifdef CONFIG_VECTOR
+static int riscv_vr_get(struct task_struct *target,
+ const struct user_regset *regset,
+ unsigned int pos, unsigned int count,
+ void *kbuf, void __user *ubuf)
+{
+ int ret;
+ struct __riscv_v_state *vstate = &target->thread.vstate;
+
+ ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf, vstate, 0,
+ offsetof(struct __riscv_v_state, vtype));
+ return ret;
+}
+
+static int riscv_vr_set(struct task_struct *target,
+ const struct user_regset *regset,
+ unsigned int pos, unsigned int count,
+ const void *kbuf, const void __user *ubuf)
+{
+ int ret;
+ struct __riscv_v_state *vstate = &target->thread.vstate;
+
+ ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, vstate, 0,
+ offsetof(struct __riscv_v_state, vtype));
+ return ret;
+}
+#endif
+
static const struct user_regset riscv_user_regset[] = {
[REGSET_X] = {
.core_note_type = NT_PRSTATUS,
@@ -111,6 +142,16 @@ static const struct user_regset riscv_user_regset[] = {
.set = &riscv_fpr_set,
},
#endif
+#ifdef CONFIG_VECTOR
+ [REGSET_V] = {
+ .core_note_type = NT_RISCV_VECTOR,
+ .n = ELF_NVREG,
+ .size = sizeof(elf_greg_t),
+ .align = sizeof(elf_greg_t),
+ .get = &riscv_vr_get,
+ .set = &riscv_vr_set,
+ },
+#endif
};

static const struct user_regset_view riscv_user_native_view = {
diff --git a/arch/riscv/kernel/signal.c b/arch/riscv/kernel/signal.c
index 17ba190e84a5..17d1b3514d4b 100644
--- a/arch/riscv/kernel/signal.c
+++ b/arch/riscv/kernel/signal.c
@@ -83,6 +83,40 @@ static long save_fp_state(struct pt_regs *regs,
#define restore_fp_state(task, regs) (0)
#endif

+#ifdef CONFIG_VECTOR
+static long restore_v_state(struct pt_regs *regs,
+ struct __riscv_v_state *sc_vregs)
+{
+ long err;
+ struct __riscv_v_state __user *state = sc_vregs;
+
+ err = __copy_from_user(&current->thread.vstate, state, sizeof(*state));
+ if (unlikely(err))
+ return err;
+
+ vstate_restore(current, regs);
+
+ return err;
+}
+
+static long save_v_state(struct pt_regs *regs,
+ struct __riscv_v_state *sc_vregs)
+{
+ long err;
+ struct __riscv_v_state __user *state = sc_vregs;
+
+ fstate_save(current, regs);
+ err = __copy_to_user(state, &current->thread.vstate, sizeof(*state));
+ if (unlikely(err))
+ return err;
+
+ return err;
+}
+#else
+#define save_v_state(task, regs) (0)
+#define restore_v_state(task, regs) (0)
+#endif
+
static long restore_sigcontext(struct pt_regs *regs,
struct sigcontext __user *sc)
{
@@ -92,6 +126,9 @@ static long restore_sigcontext(struct pt_regs *regs,
/* Restore the floating-point state. */
if (has_fpu)
err |= restore_fp_state(regs, &sc->sc_fpregs);
+ /* Restore the vector state. */
+ if (has_vector)
+ err |= restore_v_state(regs, &sc->sc_vregs);
return err;
}

@@ -145,6 +182,9 @@ static long setup_sigcontext(struct rt_sigframe __user *frame,
/* Save the floating-point state. */
if (has_fpu)
err |= save_fp_state(regs, &sc->sc_fpregs);
+ /* Save the vector state. */
+ if (has_vector)
+ err |= save_v_state(regs, &sc->sc_vregs);
return err;
}

diff --git a/arch/riscv/kernel/vector.S b/arch/riscv/kernel/vector.S
new file mode 100644
index 000000000000..7e698e6c55ad
--- /dev/null
+++ b/arch/riscv/kernel/vector.S
@@ -0,0 +1,84 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2012 Regents of the University of California
+ * Copyright (C) 2017 SiFive
+ * Copyright (C) 2019 T-HEAD
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, version 2.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/linkage.h>
+
+#include <asm/asm.h>
+#include <asm/csr.h>
+#include <asm/asm-offsets.h>
+
+ENTRY(__vstate_save)
+ li a2, TASK_THREAD_V0
+ add a0, a0, a2
+
+ li t1, (SR_VS | SR_FS)
+ csrs sstatus, t1
+
+ csrr t0, CSR_VSTART
+ sd t0, TASK_THREAD_VSTART_V0(a0)
+ csrr t0, CSR_VXSAT
+ sd t0, TASK_THREAD_VXSAT_V0(a0)
+ csrr t0, CSR_VXRM
+ sd t0, TASK_THREAD_VXRM_V0(a0)
+ csrr t0, CSR_VL
+ sd t0, TASK_THREAD_VL_V0(a0)
+ csrr t0, CSR_VTYPE
+ sd t0, TASK_THREAD_VTYPE_V0(a0)
+
+ vsetvli t0, x0, e8,m8
+ vsb.v v0, (a0)
+ addi a0, a0, RISCV_VECTOR_VLENB
+ vsb.v v8, (a0)
+ addi a0, a0, RISCV_VECTOR_VLENB
+ vsb.v v16, (a0)
+ addi a0, a0, RISCV_VECTOR_VLENB
+ vsb.v v24, (a0)
+
+ csrc sstatus, t1
+ ret
+ENDPROC(__vstate_save)
+
+ENTRY(__vstate_restore)
+ li a2, TASK_THREAD_V0
+ add a0, a0, a2
+ mv t2, a0
+
+ li t1, (SR_VS | SR_FS)
+ csrs sstatus, t1
+
+ vsetvli t0, x0, e8,m8
+ vlb.v v0, (a0)
+ addi a0, a0, RISCV_VECTOR_VLENB
+ vlb.v v8, (a0)
+ addi a0, a0, RISCV_VECTOR_VLENB
+ vlb.v v16, (a0)
+ addi a0, a0, RISCV_VECTOR_VLENB
+ vlb.v v24, (a0)
+
+ mv a0, t2
+ ld t0, TASK_THREAD_VSTART_V0(a0)
+ csrw CSR_VSTART, t0
+ ld t0, TASK_THREAD_VXSAT_V0(a0)
+ csrw CSR_VXSAT, t0
+ ld t0, TASK_THREAD_VXRM_V0(a0)
+ csrw CSR_VXRM, t0
+ ld t0, TASK_THREAD_VL_V0(a0)
+ ld t2, TASK_THREAD_VTYPE_V0(a0)
+ vsetvl t0, t0, t2
+
+ csrc sstatus, t1
+ ret
+ENDPROC(__vstate_restore)
diff --git a/include/uapi/linux/elf.h b/include/uapi/linux/elf.h
index 34c02e4290fe..e428f9e8710a 100644
--- a/include/uapi/linux/elf.h
+++ b/include/uapi/linux/elf.h
@@ -428,6 +428,7 @@ typedef struct elf64_shdr {
#define NT_MIPS_DSP 0x800 /* MIPS DSP ASE registers */
#define NT_MIPS_FP_MODE 0x801 /* MIPS floating-point mode */
#define NT_MIPS_MSA 0x802 /* MIPS SIMD registers */
+#define NT_RISCV_VECTOR 0x900 /* RISC-V vector registers */

/* Note header in a PT_NOTE section */
typedef struct elf32_note {
--
2.17.0
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