This patch adds task switch support for vector. It supports partial lazy
save and restore mechanism. It also supports all lengths of vlen.
[[email protected]: First available porting to support vector
context switching]
[[email protected]: Rewrite vector.S to support dynamic vlen, xlen and
code refine]
[[email protected]: Fix the might_sleep issue in vstate_save,
vstate_restore]
[[email protected]: Optimize task switch codes of vector]
[[email protected]: Fix the arch_release_task_struct free wrong
datap issue]
Suggested-by: Andrew Waterman <[email protected]>
Co-developed-by: Nick Knight <[email protected]>
Signed-off-by: Nick Knight <[email protected]>
Co-developed-by: Guo Ren <[email protected]>
Signed-off-by: Guo Ren <[email protected]>
Co-developed-by: Vincent Chen <[email protected]>
Signed-off-by: Vincent Chen <[email protected]>
Co-developed-by: Ruinland Tsai <[email protected]>
Signed-off-by: Ruinland Tsai <[email protected]>
Signed-off-by: Greentime Hu <[email protected]>
---
arch/riscv/include/asm/switch_to.h | 66 ++++++++++++++++++++++++++++++
arch/riscv/kernel/Makefile | 1 +
arch/riscv/kernel/process.c | 43 +++++++++++++++++++
3 files changed, 110 insertions(+)
diff --git a/arch/riscv/include/asm/switch_to.h b/arch/riscv/include/asm/switch_to.h
index ec83770b3d98..6836c51885ce 100644
--- a/arch/riscv/include/asm/switch_to.h
+++ b/arch/riscv/include/asm/switch_to.h
@@ -7,10 +7,12 @@
#define _ASM_RISCV_SWITCH_TO_H
#include <linux/jump_label.h>
+#include <linux/slab.h>
#include <linux/sched/task_stack.h>
#include <asm/processor.h>
#include <asm/ptrace.h>
#include <asm/csr.h>
+#include <asm/asm-offsets.h>
#ifdef CONFIG_FPU
extern void __fstate_save(struct task_struct *save_to);
@@ -68,6 +70,68 @@ static __always_inline bool has_fpu(void) { return false; }
#define __switch_to_fpu(__prev, __next) do { } while (0)
#endif
+#ifdef CONFIG_VECTOR
+extern struct static_key_false cpu_hwcap_vector;
+static __always_inline bool has_vector(void)
+{
+ return static_branch_likely(&cpu_hwcap_vector);
+}
+extern unsigned long riscv_vsize;
+extern void __vstate_save(struct __riscv_v_state *save_to, void *datap);
+extern void __vstate_restore(struct __riscv_v_state *restore_from, void *datap);
+
+static inline void __vstate_clean(struct pt_regs *regs)
+{
+ regs->status = (regs->status & ~(SR_VS)) | SR_VS_CLEAN;
+}
+
+static inline void vstate_off(struct task_struct *task,
+ struct pt_regs *regs)
+{
+ regs->status = (regs->status & ~SR_VS) | SR_VS_OFF;
+}
+
+static inline void vstate_save(struct task_struct *task,
+ struct pt_regs *regs)
+{
+ if ((regs->status & SR_VS) == SR_VS_DIRTY) {
+ struct __riscv_v_state *vstate = &(task->thread.vstate);
+
+ __vstate_save(vstate, vstate->datap);
+ __vstate_clean(regs);
+ }
+}
+
+static inline void vstate_restore(struct task_struct *task,
+ struct pt_regs *regs)
+{
+ if ((regs->status & SR_VS) != SR_VS_OFF) {
+ struct __riscv_v_state *vstate = &(task->thread.vstate);
+
+ __vstate_restore(vstate, vstate->datap);
+ __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));
+}
+
+#else
+static __always_inline bool has_vector(void) { return false; }
+#define riscv_vsize (0)
+#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 *,
struct task_struct *);
@@ -77,6 +141,8 @@ do { \
struct task_struct *__next = (next); \
if (has_fpu()) \
__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/kernel/Makefile b/arch/riscv/kernel/Makefile
index 87adbe47bc15..5dc550a9fb45 100644
--- a/arch/riscv/kernel/Makefile
+++ b/arch/riscv/kernel/Makefile
@@ -40,6 +40,7 @@ obj-$(CONFIG_MMU) += vdso.o vdso/
obj-$(CONFIG_RISCV_M_MODE) += traps_misaligned.o
obj-$(CONFIG_FPU) += fpu.o
+obj-$(CONFIG_VECTOR) += vector.o
obj-$(CONFIG_SMP) += smpboot.o
obj-$(CONFIG_SMP) += smp.o
obj-$(CONFIG_SMP) += cpu_ops.o
diff --git a/arch/riscv/kernel/process.c b/arch/riscv/kernel/process.c
index 504b496787aa..64568a465c6e 100644
--- a/arch/riscv/kernel/process.c
+++ b/arch/riscv/kernel/process.c
@@ -96,6 +96,25 @@ void start_thread(struct pt_regs *regs, unsigned long pc,
*/
fstate_restore(current, regs);
}
+
+ if (has_vector()) {
+ struct __riscv_v_state *vstate = &(current->thread.vstate);
+
+ /* Enable vector and allocate memory for vector registers. */
+ if (!vstate->datap) {
+ vstate->datap = kzalloc(riscv_vsize, GFP_KERNEL);
+ if (WARN_ON(!vstate->datap))
+ return;
+ }
+ 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;
}
@@ -111,15 +130,29 @@ void flush_thread(void)
fstate_off(current, task_pt_regs(current));
memset(¤t->thread.fstate, 0, sizeof(current->thread.fstate));
#endif
+#ifdef CONFIG_VECTOR
+ /* Reset vector state */
+ vstate_off(current, task_pt_regs(current));
+ memset(¤t->thread.vstate, 0, RISCV_V_STATE_DATAP);
+#endif
}
int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
{
fstate_save(src, task_pt_regs(src));
*dst = *src;
+ dst->thread.vstate.datap = NULL;
+
return 0;
}
+void arch_release_task_struct(struct task_struct *tsk)
+{
+ /* Free the vector context of datap. */
+ if (has_vector() && tsk->thread.vstate.datap)
+ kfree(tsk->thread.vstate.datap);
+}
+
int copy_thread(unsigned long clone_flags, unsigned long usp, unsigned long arg,
struct task_struct *p, unsigned long tls)
{
@@ -136,7 +169,17 @@ int copy_thread(unsigned long clone_flags, unsigned long usp, unsigned long arg,
p->thread.ra = (unsigned long)ret_from_kernel_thread;
p->thread.s[0] = usp; /* fn */
p->thread.s[1] = arg;
+ p->thread.vstate.datap = NULL;
} else {
+ /* Allocate the datap for the user process if datap is NULL */
+ if (has_vector() && !p->thread.vstate.datap) {
+ void *datap = kzalloc(riscv_vsize, GFP_KERNEL);
+ /* Failed to allocate memory. */
+ if (!datap)
+ return -ENOMEM;
+ p->thread.vstate.datap = datap;
+ memset(&p->thread.vstate, 0, RISCV_V_STATE_DATAP);
+ }
*childregs = *(current_pt_regs());
if (usp) /* User fork */
childregs->sp = usp;
--
2.17.1
Hi Greentime,
I love your patch! Perhaps something to improve:
[auto build test WARNING on linux/master]
[also build test WARNING on linus/master v5.18-rc6]
[cannot apply to kees/for-next/execve next-20220511]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]
url: https://github.com/intel-lab-lkp/linux/commits/Greentime-Hu/riscv-Add-vector-ISA-support/20220511-163610
base: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git feb9c5e19e913b53cb536a7aa7c9f20107bb51ec
config: riscv-allnoconfig (https://download.01.org/0day-ci/archive/20220511/[email protected]/config)
compiler: riscv64-linux-gcc (GCC) 11.3.0
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# https://github.com/intel-lab-lkp/linux/commit/dcb5b4bc0fc33bba0eb3219b9a8d29ddff58bbef
git remote add linux-review https://github.com/intel-lab-lkp/linux
git fetch --no-tags linux-review Greentime-Hu/riscv-Add-vector-ISA-support/20220511-163610
git checkout dcb5b4bc0fc33bba0eb3219b9a8d29ddff58bbef
# save the config file
mkdir build_dir && cp config build_dir/.config
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.3.0 make.cross W=1 O=build_dir ARCH=riscv SHELL=/bin/bash arch/riscv/kernel/
If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <[email protected]>
All warnings (new ones prefixed by >>):
>> arch/riscv/kernel/process.c:149:6: warning: no previous prototype for 'arch_release_task_struct' [-Wmissing-prototypes]
149 | void arch_release_task_struct(struct task_struct *tsk)
| ^~~~~~~~~~~~~~~~~~~~~~~~
vim +/arch_release_task_struct +149 arch/riscv/kernel/process.c
148
> 149 void arch_release_task_struct(struct task_struct *tsk)
150 {
151 /* Free the vector context of datap. */
152 if (has_vector() && tsk->thread.vstate.datap)
153 kfree(tsk->thread.vstate.datap);
154 }
155
--
0-DAY CI Kernel Test Service
https://01.org/lkp
Hi Greentime,
I love your patch! Perhaps something to improve:
[auto build test WARNING on linux/master]
[also build test WARNING on linus/master v5.18-rc6]
[cannot apply to kees/for-next/execve next-20220511]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]
url: https://github.com/intel-lab-lkp/linux/commits/Greentime-Hu/riscv-Add-vector-ISA-support/20220511-163610
base: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git feb9c5e19e913b53cb536a7aa7c9f20107bb51ec
config: riscv-randconfig-r031-20220509 (https://download.01.org/0day-ci/archive/20220512/[email protected]/config)
compiler: clang version 15.0.0 (https://github.com/llvm/llvm-project 18dd123c56754edf62c7042dcf23185c3727610f)
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# install riscv cross compiling tool for clang build
# apt-get install binutils-riscv64-linux-gnu
# https://github.com/intel-lab-lkp/linux/commit/dcb5b4bc0fc33bba0eb3219b9a8d29ddff58bbef
git remote add linux-review https://github.com/intel-lab-lkp/linux
git fetch --no-tags linux-review Greentime-Hu/riscv-Add-vector-ISA-support/20220511-163610
git checkout dcb5b4bc0fc33bba0eb3219b9a8d29ddff58bbef
# save the config file
mkdir build_dir && cp config build_dir/.config
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=riscv SHELL=/bin/bash arch/riscv/kernel/
If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <[email protected]>
All warnings (new ones prefixed by >>):
>> arch/riscv/kernel/process.c:149:6: warning: no previous prototype for function 'arch_release_task_struct' [-Wmissing-prototypes]
void arch_release_task_struct(struct task_struct *tsk)
^
arch/riscv/kernel/process.c:149:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
void arch_release_task_struct(struct task_struct *tsk)
^
static
1 warning generated.
vim +/arch_release_task_struct +149 arch/riscv/kernel/process.c
148
> 149 void arch_release_task_struct(struct task_struct *tsk)
150 {
151 /* Free the vector context of datap. */
152 if (has_vector() && tsk->thread.vstate.datap)
153 kfree(tsk->thread.vstate.datap);
154 }
155
--
0-DAY CI Kernel Test Service
https://01.org/lkp