[PATCH 4/5] ARC: add support for DSP-enabled userspace applications

From: Eugeniy Paltsev
Date: Fri Dec 27 2019 - 13:04:21 EST

Next message: Sasha Levin: "[PATCH AUTOSEL 4.14 43/57] perf/x86/intel: Fix PT PMI handling"
Previous message: Eugeniy Paltsev: "[PATCH 3/5] ARC: handle DSP presence in HW"
In reply to: Eugeniy Paltsev: "[PATCH 3/5] ARC: handle DSP presence in HW"
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]

To be able to run DSP-enabled userspace applications we need to
save and restore following DSP-related registers:
At IRQ/exception entry/exit:
* ACC0_GLO, ACC0_GHI, DSP_CTRL
* ACC0_LO, ACC0_HI (we already save them as r58, r59 pair)
At context switch:
* DSP_BFLY0, DSP_FFT_CTRL

Signed-off-by: Eugeniy Paltsev <Eugeniy.Paltsev@xxxxxxxxxxxx>
---
arch/arc/Kconfig | 7 +++
arch/arc/include/asm/arcregs.h | 2 +
arch/arc/include/asm/dsp-impl.h | 75 +++++++++++++++++++++++++++++-
arch/arc/include/asm/dsp.h | 42 +++++++++++++++++
arch/arc/include/asm/entry-arcv2.h | 3 ++
arch/arc/include/asm/processor.h | 4 ++
arch/arc/include/asm/ptrace.h | 4 ++
arch/arc/include/asm/switch_to.h | 2 +
arch/arc/kernel/asm-offsets.c | 7 +++
arch/arc/kernel/setup.c | 2 +-
10 files changed, 146 insertions(+), 2 deletions(-)
create mode 100644 arch/arc/include/asm/dsp.h

diff --git a/arch/arc/Kconfig b/arch/arc/Kconfig
index b9cd7ce3f878..c3210754a3d2 100644
--- a/arch/arc/Kconfig
+++ b/arch/arc/Kconfig
@@ -432,6 +432,13 @@ config ARC_DSP_KERNEL
DSP extension presence in HW, no support for DSP-enabled userspace
applications. We don't save / restore DSP registers and only do
some minimal preparations so userspace won't be able to break kernel
+
+config ARC_DSP_USERSPACE
+ bool "Support DSP for userspace apps"
+ select ARC_HAS_ACCL_REGS
+ help
+ DSP extension presence in HW, support save / restore DSP registers to
+ run DSP-enabled userspace applications
endchoice

config ARC_IRQ_NO_AUTOSAVE
diff --git a/arch/arc/include/asm/arcregs.h b/arch/arc/include/asm/arcregs.h
index 0004b1e9b325..a713819cab3c 100644
--- a/arch/arc/include/asm/arcregs.h
+++ b/arch/arc/include/asm/arcregs.h
@@ -118,6 +118,8 @@

/*
* DSP-related registers
+ * Registers names must correspond to dsp_callee_regs structure fields names
+ * for automatic offset calculation in DSP_AUX_SAVE_RESTORE macros.
*/
#define ARC_AUX_DSP_BUILD 0x7A
#define ARC_AUX_ACC0_LO 0x580
diff --git a/arch/arc/include/asm/dsp-impl.h b/arch/arc/include/asm/dsp-impl.h
index 788093cbe689..7b640a680dfc 100644
--- a/arch/arc/include/asm/dsp-impl.h
+++ b/arch/arc/include/asm/dsp-impl.h
@@ -7,6 +7,8 @@
#ifndef __ASM_ARC_DSP_IMPL_H
#define __ASM_ARC_DSP_IMPL_H

+#include <asm/dsp.h>
+
#define DSP_CTRL_DISABLED_ALL 0

#ifdef __ASSEMBLY__
@@ -28,11 +30,82 @@
* able to break kernel */
mov r58, DSP_CTRL_DISABLED_ALL
sr r58, [ARC_AUX_DSP_CTRL]
-#endif /* ARC_DSP_KERNEL */
+
+#elif defined(ARC_DSP_SAVE_RESTORE_REGS)
+ lr r58, [ARC_AUX_ACC0_GLO]
+ lr r59, [ARC_AUX_ACC0_GHI]
+ ST2 r58, r59, PT_ACC0_GLO
+
+ lr r58, [ARC_AUX_DSP_CTRL]
+ st r58, [sp, PT_DSP_CTRL]
+
+#endif
+.endm
+
+/* clobbers r58, r59 registers pair */
+.macro DSP_RESTORE_REGFILE_IRQ
+#if defined(ARC_DSP_SAVE_RESTORE_REGS)
+ LD2 r58, r59, PT_ACC0_GLO
+ sr r58, [ARC_AUX_ACC0_GLO]
+ sr r59, [ARC_AUX_ACC0_GHI]
+
+ ld r58, [sp, PT_DSP_CTRL]
+ sr r58, [ARC_AUX_DSP_CTRL]
+
+#endif
.endm

#else /* __ASEMBLY__ */

+#include <linux/sched.h>
+#include <asm/switch_to.h>
+
+#ifdef ARC_DSP_SAVE_RESTORE_REGS
+
+/*
+ * As we save new and restore old AUX register value in the same place we
+ * can optimize a bit and use AEX instruction (swap contents of an auxiliary
+ * register with a core register) instead of LR + SR pair.
+ */
+#define AUX_SAVE_RESTORE(_saveto, _readfrom, _offt, _aux, _scratch) \
+do { \
+ __asm__ __volatile__( \
+ "ld %0, [%2, %4] \n" \
+ "aex %0, [%3] \n" \
+ "st %0, [%1, %4] \n" \
+ : \
+ "=&r" (_scratch) /* must be early clobber */ \
+ : \
+ "r" (_saveto), \
+ "r" (_readfrom), \
+ "I" (_aux), \
+ "I" (_offt) \
+ : \
+ "memory" \
+ ); \
+} while (0)
+
+#define DSP_AUX_SAVE_RESTORE(_saveto, _readfrom, _aux, _scratch) \
+ AUX_SAVE_RESTORE(_saveto, _readfrom, \
+ offsetof(struct dsp_callee_regs, _aux), \
+ ARC_AUX_##_aux, _scratch)
+
+static inline void arc_dsp_save_restore(struct task_struct *prev,
+ struct task_struct *next)
+{
+ long unsigned int *saveto = &prev->thread.dsp.DSP_BFLY0;
+ long unsigned int *readfrom = &next->thread.dsp.DSP_BFLY0;
+
+ long unsigned int zero = 0;
+
+ DSP_AUX_SAVE_RESTORE(saveto, readfrom, DSP_BFLY0, zero);
+ DSP_AUX_SAVE_RESTORE(saveto, readfrom, DSP_FFT_CTRL, zero);
+}
+
+#else /* !ARC_DSP_SAVE_RESTORE_REGS */
+#define arc_dsp_save_restore(p, n)
+#endif /* ARC_DSP_SAVE_RESTORE_REGS */
+
static inline bool dsp_exist(void)
{
struct bcr_generic bcr;
diff --git a/arch/arc/include/asm/dsp.h b/arch/arc/include/asm/dsp.h
new file mode 100644
index 000000000000..68507f04dea4
--- /dev/null
+++ b/arch/arc/include/asm/dsp.h
@@ -0,0 +1,42 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (C) 2020 Synopsys, Inc. (www.synopsys.com)
+ *
+ * Author: Eugeniy Paltsev <Eugeniy.Paltsev@xxxxxxxxxxxx>
+ */
+#ifndef __ASM_ARC_DSP_H
+#define __ASM_ARC_DSP_H
+
+#if defined(CONFIG_ARC_DSP_USERSPACE)
+#define ARC_DSP_SAVE_RESTORE_REGS 1
+#endif
+
+#ifndef __ASSEMBLY__
+
+/* some defines to simplify config sanitize in kernel/setup.c */
+#if defined(CONFIG_ARC_DSP_KERNEL) || \
+ defined(CONFIG_ARC_DSP_USERSPACE)
+#define ARC_DSP_HANDLED 1
+#else
+#define ARC_DSP_HANDLED 0
+#endif
+
+#if defined(CONFIG_ARC_DSP_USERSPACE)
+#define ARC_DSP_OPT_NAME "CONFIG_ARC_DSP_USERSPACE"
+#else
+#define ARC_DSP_OPT_NAME "CONFIG_ARC_DSP_KERNEL"
+#endif
+
+/*
+ * DSP-related saved registers - need to be saved only when you are
+ * scheduled out.
+ * structure fields name must correspond to aux register defenitions for
+ * automatic offset calculation in DSP_AUX_SAVE_RESTORE macros
+ */
+struct dsp_callee_regs {
+ unsigned long DSP_BFLY0, DSP_FFT_CTRL;
+};
+
+#endif /* !__ASSEMBLY__ */
+
+#endif /* __ASM_ARC_DSP_H */
diff --git a/arch/arc/include/asm/entry-arcv2.h b/arch/arc/include/asm/entry-arcv2.h
index e3f8bd3e2eba..5d079f0b6243 100644
--- a/arch/arc/include/asm/entry-arcv2.h
+++ b/arch/arc/include/asm/entry-arcv2.h
@@ -192,6 +192,9 @@
ld r25, [sp, PT_user_r25]
#endif

+ /* clobbers r58, r59 registers pair, so must be before r58, r59 restore */
+ DSP_RESTORE_REGFILE_IRQ
+
#ifdef CONFIG_ARC_HAS_ACCL_REGS
LD2 r58, r59, PT_r58
#endif
diff --git a/arch/arc/include/asm/processor.h b/arch/arc/include/asm/processor.h
index 706edeaa5583..1716df0f4472 100644
--- a/arch/arc/include/asm/processor.h
+++ b/arch/arc/include/asm/processor.h
@@ -14,6 +14,7 @@
#ifndef __ASSEMBLY__

#include <asm/ptrace.h>
+#include <asm/dsp.h>

#ifdef CONFIG_ARC_FPU_SAVE_RESTORE
/* These DPFP regs need to be saved/restored across ctx-sw */
@@ -39,6 +40,9 @@ struct thread_struct {
unsigned long ksp; /* kernel mode stack pointer */
unsigned long callee_reg; /* pointer to callee regs */
unsigned long fault_address; /* dbls as brkpt holder as well */
+#ifdef ARC_DSP_SAVE_RESTORE_REGS
+ struct dsp_callee_regs dsp;
+#endif
#ifdef CONFIG_ARC_FPU_SAVE_RESTORE
struct arc_fpu fpu;
#endif
diff --git a/arch/arc/include/asm/ptrace.h b/arch/arc/include/asm/ptrace.h
index ba9854ef39e8..a5851ee141de 100644
--- a/arch/arc/include/asm/ptrace.h
+++ b/arch/arc/include/asm/ptrace.h
@@ -8,6 +8,7 @@
#define __ASM_ARC_PTRACE_H

#include <uapi/asm/ptrace.h>
+#include <asm/dsp.h>

#ifndef __ASSEMBLY__

@@ -91,6 +92,9 @@ struct pt_regs {
#ifdef CONFIG_ARC_HAS_ACCL_REGS
unsigned long r58, r59; /* ACCL/ACCH used by FPU / DSP MPY */
#endif
+#ifdef ARC_DSP_SAVE_RESTORE_REGS
+ unsigned long ACC0_GLO, ACC0_GHI, DSP_CTRL;
+#endif

/*------- Below list auto saved by h/w -----------*/
unsigned long r0, r1, r2, r3, r4, r5, r6, r7, r8, r9, r10, r11;
diff --git a/arch/arc/include/asm/switch_to.h b/arch/arc/include/asm/switch_to.h
index 77f123385e96..b49f025136af 100644
--- a/arch/arc/include/asm/switch_to.h
+++ b/arch/arc/include/asm/switch_to.h
@@ -9,6 +9,7 @@
#ifndef __ASSEMBLY__

#include <linux/sched.h>
+#include <asm/dsp-impl.h>

#ifdef CONFIG_ARC_FPU_SAVE_RESTORE

@@ -37,6 +38,7 @@ struct task_struct *__switch_to(struct task_struct *p, struct task_struct *n);
do { \
ARC_EZNPS_DP_PREV(prev, next); \
ARC_FPU_PREV(prev, next); \
+ arc_dsp_save_restore(prev, next);\
last = __switch_to(prev, next);\
ARC_FPU_NEXT(next); \
mb(); \
diff --git a/arch/arc/kernel/asm-offsets.c b/arch/arc/kernel/asm-offsets.c
index c783bcd35eb8..f74426a71ba8 100644
--- a/arch/arc/kernel/asm-offsets.c
+++ b/arch/arc/kernel/asm-offsets.c
@@ -11,6 +11,8 @@
#include <linux/ptrace.h>
#include <asm/hardirq.h>
#include <asm/page.h>
+#include <asm/dsp.h>
+

int main(void)
{
@@ -75,6 +77,11 @@ int main(void)
OFFSET(PT_r58, pt_regs, r58);
OFFSET(PT_r59, pt_regs, r59);
#endif
+#ifdef ARC_DSP_SAVE_RESTORE_REGS
+ OFFSET(PT_ACC0_GLO, pt_regs, ACC0_GLO);
+ OFFSET(PT_ACC0_GHI, pt_regs, ACC0_GHI);
+ OFFSET(PT_DSP_CTRL, pt_regs, DSP_CTRL);
+#endif

return 0;
}
diff --git a/arch/arc/kernel/setup.c b/arch/arc/kernel/setup.c
index b3995dd673d9..30d31579c51d 100644
--- a/arch/arc/kernel/setup.c
+++ b/arch/arc/kernel/setup.c
@@ -447,7 +447,7 @@ static void arc_chk_core_config(void)
CHK_OPT_STRICT(CONFIG_ARC_HAS_ACCL_REGS, present);

present = dsp_exist();
- CHK_OPT_STRICT(CONFIG_ARC_DSP_KERNEL, present);
+ chk_opt_strict(ARC_DSP_OPT_NAME, present, ARC_DSP_HANDLED);
}
}

--
2.21.0

Next message: Sasha Levin: "[PATCH AUTOSEL 4.14 43/57] perf/x86/intel: Fix PT PMI handling"
Previous message: Eugeniy Paltsev: "[PATCH 3/5] ARC: handle DSP presence in HW"
In reply to: Eugeniy Paltsev: "[PATCH 3/5] ARC: handle DSP presence in HW"
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]