[U-Boot] [PATCH v3 00/11] SMP support for RISC-V

[U-Boot] [PATCH v3 00/11] SMP support for RISC-V

[Lukas Auer]

This patch series adds SMP support for RISC-V to U-Boot. It allows
U-Boot to run on multi-hart systems (hart is the RISC-V terminology for
hardware thread). Images passed to bootm will be started on all harts.
The bootm command is currently the only one that will boot images on all
harts, bootefi is not yet supported.

The patches have been successfully tested on both QEMU (machine and
supervisor mode) and the HiFive Unleashed board (supervisor mode), using
BBL and OpenSBI.
Mainline QEMU requires two patches [1, 2] to run in this configuration.
Patch [1] has been dropped and will be replaced with a U-Boot patch.

[1]: https://patchwork.ozlabs.org/patch/1039493/
[2]: https://patchwork.ozlabs.org/patch/1039082/

Changes in v3:
- Print error if riscv_send_ipi() fails
- Adjust error message for failures of riscv_clear_ipi() to match error
message for failures of riscv_send_ipi()
- New patch to save the hart ID in register tp instead of s0
- Adjust patch to use the new location of the hart ID (register tp)
- New patch to hang if relocation of secondary harts fails

Changes in v2:
- Remove unneeded quotes from NR_CPUS Kconfig entry
- Move memory barrier from send_ipi_many() to handle_ipi()
- Add check in send_ipi_many so that IPIs are only sent to available
harts as indicated by the available_harts mask
- Implement hart lottery to pick main hart to run U-Boot
- Remove CONFIG_MAIN_HART as it is not required anymore
- Register available harts in the available_harts mask
- New patch to populate register a0 with the hart ID from the mhartid
CSR in machine-mode
- New patch to enable SMP on the SiFive FU540, which was previously sent
independently

Lukas Auer (11):
  riscv: add infrastructure for calling functions on other harts
  riscv: import the supervisor binary interface header file
  riscv: implement IPI platform functions using SBI
  riscv: delay initialization of caches and debug UART
  riscv: save hart ID in register tp instead of s0
  riscv: add support for multi-hart systems
  riscv: boot images passed to bootm on all harts
  riscv: do not rely on hart ID passed by previous boot stage
  riscv: hang if relocation of secondary harts fails
  riscv: fu540: enable SMP
  riscv: qemu: enable SMP

 arch/riscv/Kconfig                   |  28 +++++
 arch/riscv/cpu/cpu.c                 |   9 +-
 arch/riscv/cpu/start.S               | 167 +++++++++++++++++++++++++--
 arch/riscv/include/asm/csr.h         |   1 +
 arch/riscv/include/asm/global_data.h |   6 +
 arch/riscv/include/asm/sbi.h         |  94 +++++++++++++++
 arch/riscv/include/asm/smp.h         |  53 +++++++++
 arch/riscv/lib/Makefile              |   2 +
 arch/riscv/lib/asm-offsets.c         |   1 +
 arch/riscv/lib/bootm.c               |  13 ++-
 arch/riscv/lib/sbi_ipi.c             |  25 ++++
 arch/riscv/lib/smp.c                 | 118 +++++++++++++++++++
 board/emulation/qemu-riscv/Kconfig   |   1 +
 board/sifive/fu540/Kconfig           |   1 +
 14 files changed, 507 insertions(+), 12 deletions(-)
 create mode 100644 arch/riscv/include/asm/sbi.h
 create mode 100644 arch/riscv/include/asm/smp.h
 create mode 100644 arch/riscv/lib/sbi_ipi.c
 create mode 100644 arch/riscv/lib/smp.c

-- 
2.20.1

[U-Boot] [PATCH v3 01/11] riscv: add infrastructure for calling functions on other harts

[Lukas Auer]

Harts on RISC-V boot independently, U-Boot is responsible for managing
them. Functions are called on other harts with smp_call_function(),
which sends inter-processor interrupts (IPIs) to all other available
harts. Available harts are those marked as available in the device tree
and present in the available_harts mask stored in global data. The
available_harts mask is used to register all harts that have entered
U-Boot. Functions are specified with their address and two function
arguments (argument 2 and 3). The first function argument is always the
hart ID of the hart calling the function. On the other harts, the IPI
interrupt handler handle_ipi() must be called on software interrupts to
handle the request and call the specified function.

Functions are stored in the ipi_data data structure. Every hart has its
own data structure in global data. While this is not required at the
moment (all harts are expected to boot Linux), this does allow future
expansion, where other harts may be used for monitoring or other tasks.

Signed-off-by: Lukas Auer <lukas.auer@aisec.fraunhofer.de>
Reviewed-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Tested-by: Bin Meng <bmeng.cn@gmail.com>
---

Changes in v3:
- Print error if riscv_send_ipi() fails
- Adjust error message for failures of riscv_clear_ipi() to match error
message for failures of riscv_send_ipi()

Changes in v2:
- Remove unneeded quotes from NR_CPUS Kconfig entry
- Move memory barrier from send_ipi_many() to handle_ipi()
- Add check in send_ipi_many so that IPIs are only sent to available
harts as indicated by the available_harts mask

 arch/riscv/Kconfig                   |  19 +++++
 arch/riscv/include/asm/global_data.h |   6 ++
 arch/riscv/include/asm/smp.h         |  53 ++++++++++++
 arch/riscv/lib/Makefile              |   1 +
 arch/riscv/lib/smp.c                 | 118 +++++++++++++++++++++++++++
 5 files changed, 197 insertions(+)
 create mode 100644 arch/riscv/include/asm/smp.h
 create mode 100644 arch/riscv/lib/smp.c

diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index 36512a8995..4d7a115569 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -120,4 +120,23 @@ config RISCV_RDTIME
 config SYS_MALLOC_F_LEN
 	default 0x1000
 
+config SMP
+	bool "Symmetric Multi-Processing"
+	help
+	  This enables support for systems with more than one CPU. If
+	  you say N here, U-Boot will run on single and multiprocessor
+	  machines, but will use only one CPU of a multiprocessor
+	  machine. If you say Y here, U-Boot will run on many, but not
+	  all, single processor machines.
+
+config NR_CPUS
+	int "Maximum number of CPUs (2-32)"
+	range 2 32
+	depends on SMP
+	default 8
+	help
+	  On multiprocessor machines, U-Boot sets up a stack for each CPU.
+	  Stack memory is pre-allocated. U-Boot must therefore know the
+	  maximum number of CPUs that may be present.
+
 endmenu
diff --git a/arch/riscv/include/asm/global_data.h b/arch/riscv/include/asm/global_data.h
index a3a342c6e1..80e3165e39 100644
--- a/arch/riscv/include/asm/global_data.h
+++ b/arch/riscv/include/asm/global_data.h
@@ -10,12 +10,18 @@
 #ifndef	__ASM_GBL_DATA_H
 #define __ASM_GBL_DATA_H
 
+#include <asm/smp.h>
+
 /* Architecture-specific global data */
 struct arch_global_data {
 	long boot_hart;		/* boot hart id */
 #ifdef CONFIG_SIFIVE_CLINT
 	void __iomem *clint;	/* clint base address */
 #endif
+#ifdef CONFIG_SMP
+	struct ipi_data ipi[CONFIG_NR_CPUS];
+#endif
+	ulong available_harts;
 };
 
 #include <asm-generic/global_data.h>
diff --git a/arch/riscv/include/asm/smp.h b/arch/riscv/include/asm/smp.h
new file mode 100644
index 0000000000..bc863fdbaf
--- /dev/null
+++ b/arch/riscv/include/asm/smp.h
@@ -0,0 +1,53 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2019 Fraunhofer AISEC,
+ * Lukas Auer <lukas.auer@aisec.fraunhofer.de>
+ */
+
+#ifndef _ASM_RISCV_SMP_H
+#define _ASM_RISCV_SMP_H
+
+/**
+ * struct ipi_data - Inter-processor interrupt (IPI) data structure
+ *
+ * IPIs are used for SMP support to communicate to other harts what function to
+ * call. Functions are in the form
+ * void (*addr)(ulong hart, ulong arg0, ulong arg1).
+ *
+ * The function address and the two arguments, arg0 and arg1, are stored in the
+ * IPI data structure. The hart ID is inserted by the hart handling the IPI and
+ * calling the function.
+ *
+ * @addr: Address of function
+ * @arg0: First argument of function
+ * @arg1: Second argument of function
+ */
+struct ipi_data {
+	ulong addr;
+	ulong arg0;
+	ulong arg1;
+};
+
+/**
+ * handle_ipi() - interrupt handler for software interrupts
+ *
+ * The IPI interrupt handler must be called to handle software interrupts. It
+ * calls the function specified in the hart's IPI data structure.
+ *
+ * @hart: Hart ID of the current hart
+ */
+void handle_ipi(ulong hart);
+
+/**
+ * smp_call_function() - Call a function on all other harts
+ *
+ * Send IPIs with the specified function call to all harts.
+ *
+ * @addr: Address of function
+ * @arg0: First argument of function
+ * @arg1: Second argument of function
+ * @return 0 if OK, -ve on error
+ */
+int smp_call_function(ulong addr, ulong arg0, ulong arg1);
+
+#endif
diff --git a/arch/riscv/lib/Makefile b/arch/riscv/lib/Makefile
index edfa61690c..19370f9749 100644
--- a/arch/riscv/lib/Makefile
+++ b/arch/riscv/lib/Makefile
@@ -14,6 +14,7 @@ obj-$(CONFIG_SIFIVE_CLINT) += sifive_clint.o
 obj-y	+= interrupts.o
 obj-y	+= reset.o
 obj-y   += setjmp.o
+obj-$(CONFIG_SMP) += smp.o
 
 # For building EFI apps
 CFLAGS_$(EFI_CRT0) := $(CFLAGS_EFI)
diff --git a/arch/riscv/lib/smp.c b/arch/riscv/lib/smp.c
new file mode 100644
index 0000000000..caa292ccd2
--- /dev/null
+++ b/arch/riscv/lib/smp.c
@@ -0,0 +1,118 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2019 Fraunhofer AISEC,
+ * Lukas Auer <lukas.auer@aisec.fraunhofer.de>
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <asm/barrier.h>
+#include <asm/smp.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+/**
+ * riscv_send_ipi() - Send inter-processor interrupt (IPI)
+ *
+ * Platform code must provide this function.
+ *
+ * @hart: Hart ID of receiving hart
+ * @return 0 if OK, -ve on error
+ */
+extern int riscv_send_ipi(int hart);
+
+/**
+ * riscv_clear_ipi() - Clear inter-processor interrupt (IPI)
+ *
+ * Platform code must provide this function.
+ *
+ * @hart: Hart ID of hart to be cleared
+ * @return 0 if OK, -ve on error
+ */
+extern int riscv_clear_ipi(int hart);
+
+static int send_ipi_many(struct ipi_data *ipi)
+{
+	ofnode node, cpus;
+	u32 reg;
+	int ret;
+
+	cpus = ofnode_path("/cpus");
+	if (!ofnode_valid(cpus)) {
+		pr_err("Can't find cpus node!\n");
+		return -EINVAL;
+	}
+
+	ofnode_for_each_subnode(node, cpus) {
+		/* skip if hart is marked as not available in the device tree */
+		if (!ofnode_is_available(node))
+			continue;
+
+		/* read hart ID of CPU */
+		ret = ofnode_read_u32(node, "reg", &reg);
+		if (ret)
+			continue;
+
+		/* skip if it is the hart we are running on */
+		if (reg == gd->arch.boot_hart)
+			continue;
+
+		if (reg >= CONFIG_NR_CPUS) {
+			pr_err("Hart ID %d is out of range, increase CONFIG_NR_CPUS\n",
+			       reg);
+			continue;
+		}
+
+		/* skip if hart is not available */
+		if (!(gd->arch.available_harts & (1 << reg)))
+			continue;
+
+		gd->arch.ipi[reg].addr = ipi->addr;
+		gd->arch.ipi[reg].arg0 = ipi->arg0;
+		gd->arch.ipi[reg].arg1 = ipi->arg1;
+
+		ret = riscv_send_ipi(reg);
+		if (ret) {
+			pr_err("Cannot send IPI to hart %d\n", reg);
+			return ret;
+		}
+	}
+
+	return 0;
+}
+
+void handle_ipi(ulong hart)
+{
+	int ret;
+	void (*smp_function)(ulong hart, ulong arg0, ulong arg1);
+
+	if (hart >= CONFIG_NR_CPUS)
+		return;
+
+	ret = riscv_clear_ipi(hart);
+	if (ret) {
+		pr_err("Cannot clear IPI of hart %ld\n", hart);
+		return;
+	}
+
+	__smp_mb();
+
+	smp_function = (void (*)(ulong, ulong, ulong))gd->arch.ipi[hart].addr;
+	invalidate_icache_all();
+
+	smp_function(hart, gd->arch.ipi[hart].arg0, gd->arch.ipi[hart].arg1);
+}
+
+int smp_call_function(ulong addr, ulong arg0, ulong arg1)
+{
+	int ret = 0;
+	struct ipi_data ipi;
+
+	ipi.addr = addr;
+	ipi.arg0 = arg0;
+	ipi.arg1 = arg1;
+
+	ret = send_ipi_many(&ipi);
+
+	return ret;
+}
-- 
2.20.1

[U-Boot] [PATCH v3 02/11] riscv: import the supervisor binary interface header file

[Lukas Auer]

Import the supervisor binary interface (SBI) header file from Linux
(arch/riscv/include/asm/sbi.h). The last change to it was in commit
6d60b6ee0c97 ("RISC-V: Device, timer, IRQs, and the SBI").

Signed-off-by: Lukas Auer <lukas.auer@aisec.fraunhofer.de>
Reviewed-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Atish Patra <atish.patra@wdc.com>
---

Changes in v3: None
Changes in v2: None

 arch/riscv/include/asm/sbi.h | 94 ++++++++++++++++++++++++++++++++++++
 1 file changed, 94 insertions(+)
 create mode 100644 arch/riscv/include/asm/sbi.h

diff --git a/arch/riscv/include/asm/sbi.h b/arch/riscv/include/asm/sbi.h
new file mode 100644
index 0000000000..ced57defdd
--- /dev/null
+++ b/arch/riscv/include/asm/sbi.h
@@ -0,0 +1,94 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2015 Regents of the University of California
+ *
+ * Taken from Linux arch/riscv/include/asm/sbi.h
+ */
+
+#ifndef _ASM_RISCV_SBI_H
+#define _ASM_RISCV_SBI_H
+
+#include <linux/types.h>
+
+#define SBI_SET_TIMER 0
+#define SBI_CONSOLE_PUTCHAR 1
+#define SBI_CONSOLE_GETCHAR 2
+#define SBI_CLEAR_IPI 3
+#define SBI_SEND_IPI 4
+#define SBI_REMOTE_FENCE_I 5
+#define SBI_REMOTE_SFENCE_VMA 6
+#define SBI_REMOTE_SFENCE_VMA_ASID 7
+#define SBI_SHUTDOWN 8
+
+#define SBI_CALL(which, arg0, arg1, arg2) ({			\
+	register uintptr_t a0 asm ("a0") = (uintptr_t)(arg0);	\
+	register uintptr_t a1 asm ("a1") = (uintptr_t)(arg1);	\
+	register uintptr_t a2 asm ("a2") = (uintptr_t)(arg2);	\
+	register uintptr_t a7 asm ("a7") = (uintptr_t)(which);	\
+	asm volatile ("ecall"					\
+		      : "+r" (a0)				\
+		      : "r" (a1), "r" (a2), "r" (a7)		\
+		      : "memory");				\
+	a0;							\
+})
+
+/* Lazy implementations until SBI is finalized */
+#define SBI_CALL_0(which) SBI_CALL(which, 0, 0, 0)
+#define SBI_CALL_1(which, arg0) SBI_CALL(which, arg0, 0, 0)
+#define SBI_CALL_2(which, arg0, arg1) SBI_CALL(which, arg0, arg1, 0)
+
+static inline void sbi_console_putchar(int ch)
+{
+	SBI_CALL_1(SBI_CONSOLE_PUTCHAR, ch);
+}
+
+static inline int sbi_console_getchar(void)
+{
+	return SBI_CALL_0(SBI_CONSOLE_GETCHAR);
+}
+
+static inline void sbi_set_timer(uint64_t stime_value)
+{
+#if __riscv_xlen == 32
+	SBI_CALL_2(SBI_SET_TIMER, stime_value, stime_value >> 32);
+#else
+	SBI_CALL_1(SBI_SET_TIMER, stime_value);
+#endif
+}
+
+static inline void sbi_shutdown(void)
+{
+	SBI_CALL_0(SBI_SHUTDOWN);
+}
+
+static inline void sbi_clear_ipi(void)
+{
+	SBI_CALL_0(SBI_CLEAR_IPI);
+}
+
+static inline void sbi_send_ipi(const unsigned long *hart_mask)
+{
+	SBI_CALL_1(SBI_SEND_IPI, hart_mask);
+}
+
+static inline void sbi_remote_fence_i(const unsigned long *hart_mask)
+{
+	SBI_CALL_1(SBI_REMOTE_FENCE_I, hart_mask);
+}
+
+static inline void sbi_remote_sfence_vma(const unsigned long *hart_mask,
+					 unsigned long start,
+					 unsigned long size)
+{
+	SBI_CALL_1(SBI_REMOTE_SFENCE_VMA, hart_mask);
+}
+
+static inline void sbi_remote_sfence_vma_asid(const unsigned long *hart_mask,
+					      unsigned long start,
+					      unsigned long size,
+					      unsigned long asid)
+{
+	SBI_CALL_1(SBI_REMOTE_SFENCE_VMA_ASID, hart_mask);
+}
+
+#endif
-- 
2.20.1

[U-Boot] [PATCH v3 03/11] riscv: implement IPI platform functions using SBI

[Lukas Auer]

The supervisor binary interface (SBI) provides the necessary functions
to implement the platform IPI functions riscv_send_ipi() and
riscv_clear_ipi(). Use it to implement them.

This adds support for inter-processor interrupts (IPIs) on RISC-V CPUs
running in supervisor mode. Support for machine mode is already
available for CPUs that include the SiFive CLINT.

Signed-off-by: Lukas Auer <lukas.auer@aisec.fraunhofer.de>
Reviewed-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Atish Patra <atish.patra@wdc.com>
Tested-by: Bin Meng <bmeng.cn@gmail.com>
---

Changes in v3: None
Changes in v2: None

 arch/riscv/Kconfig       |  5 +++++
 arch/riscv/lib/Makefile  |  1 +
 arch/riscv/lib/sbi_ipi.c | 25 +++++++++++++++++++++++++
 3 files changed, 31 insertions(+)
 create mode 100644 arch/riscv/lib/sbi_ipi.c

diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index 4d7a115569..9da609b33b 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -139,4 +139,9 @@ config NR_CPUS
 	  Stack memory is pre-allocated. U-Boot must therefore know the
 	  maximum number of CPUs that may be present.
 
+config SBI_IPI
+	bool
+	default y if RISCV_SMODE
+	depends on SMP
+
 endmenu
diff --git a/arch/riscv/lib/Makefile b/arch/riscv/lib/Makefile
index 19370f9749..35dbf643e4 100644
--- a/arch/riscv/lib/Makefile
+++ b/arch/riscv/lib/Makefile
@@ -13,6 +13,7 @@ obj-$(CONFIG_RISCV_RDTIME) += rdtime.o
 obj-$(CONFIG_SIFIVE_CLINT) += sifive_clint.o
 obj-y	+= interrupts.o
 obj-y	+= reset.o
+obj-$(CONFIG_SBI_IPI) += sbi_ipi.o
 obj-y   += setjmp.o
 obj-$(CONFIG_SMP) += smp.o
 
diff --git a/arch/riscv/lib/sbi_ipi.c b/arch/riscv/lib/sbi_ipi.c
new file mode 100644
index 0000000000..170346da68
--- /dev/null
+++ b/arch/riscv/lib/sbi_ipi.c
@@ -0,0 +1,25 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2019 Fraunhofer AISEC,
+ * Lukas Auer <lukas.auer@aisec.fraunhofer.de>
+ */
+
+#include <common.h>
+#include <asm/sbi.h>
+
+int riscv_send_ipi(int hart)
+{
+	ulong mask;
+
+	mask = 1UL << hart;
+	sbi_send_ipi(&mask);
+
+	return 0;
+}
+
+int riscv_clear_ipi(int hart)
+{
+	sbi_clear_ipi();
+
+	return 0;
+}
-- 
2.20.1

[U-Boot] [PATCH v3 04/11] riscv: delay initialization of caches and debug UART

[Lukas Auer]

Move the initialization of the caches and the debug UART until after
board_init_f_init_reserve. This is in preparation for SMP support, where
code prior to this point will be executed by all harts. This ensures
that initialization will only be performed once on the main hart running
U-Boot.

Signed-off-by: Lukas Auer <lukas.auer@aisec.fraunhofer.de>
Reviewed-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
---

Changes in v3: None
Changes in v2: None

 arch/riscv/cpu/start.S | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/arch/riscv/cpu/start.S b/arch/riscv/cpu/start.S
index 81ea52b170..a30f6f7194 100644
--- a/arch/riscv/cpu/start.S
+++ b/arch/riscv/cpu/start.S
@@ -45,10 +45,6 @@ _start:
 	/* mask all interrupts */
 	csrw	MODE_PREFIX(ie), zero
 
-	/* Enable cache */
-	jal	icache_enable
-	jal	dcache_enable
-
 /*
  * Set stackpointer in internal/ex RAM to call board_init_f
  */
@@ -57,10 +53,6 @@ call_board_init_f:
 	li	t1, CONFIG_SYS_INIT_SP_ADDR
 	and	sp, t1, t0		/* force 16 byte alignment */
 
-#ifdef CONFIG_DEBUG_UART
-	jal	debug_uart_init
-#endif
-
 call_board_init_f_0:
 	mv	a0, sp
 	jal	board_init_f_alloc_reserve
@@ -74,6 +66,14 @@ call_board_init_f_0:
 	/* save the boot hart id to global_data */
 	SREG	s0, GD_BOOT_HART(gp)
 
+	/* Enable cache */
+	jal	icache_enable
+	jal	dcache_enable
+
+#ifdef CONFIG_DEBUG_UART
+	jal	debug_uart_init
+#endif
+
 	mv	a0, zero		/* a0 <-- boot_flags = 0 */
 	la	t5, board_init_f
 	jr	t5			/* jump to board_init_f() */
-- 
2.20.1

[U-Boot] [PATCH v3 05/11] riscv: save hart ID in register tp instead of s0

[Lukas Auer]

The hart ID passed by the previous boot stage is currently stored in
register s0. If we divert the control flow inside a function, which is
required as part of multi-hart support, the function epilog may not be
called, clobbering register s0. Save the hart ID in the unallocatable
register tp instead to protect the hart ID.

Signed-off-by: Lukas Auer <lukas.auer@aisec.fraunhofer.de>
---

Changes in v3:
- New patch to save the hart ID in register tp instead of s0

Changes in v2: None

 arch/riscv/cpu/start.S | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/riscv/cpu/start.S b/arch/riscv/cpu/start.S
index a30f6f7194..bcc0ff696d 100644
--- a/arch/riscv/cpu/start.S
+++ b/arch/riscv/cpu/start.S
@@ -36,7 +36,7 @@
 .globl _start
 _start:
 	/* save hart id and dtb pointer */
-	mv	s0, a0
+	mv	tp, a0
 	mv	s1, a1
 
 	la	t0, trap_entry
@@ -64,7 +64,7 @@ call_board_init_f_0:
 	jal	board_init_f_init_reserve
 
 	/* save the boot hart id to global_data */
-	SREG	s0, GD_BOOT_HART(gp)
+	SREG	tp, GD_BOOT_HART(gp)
 
 	/* Enable cache */
 	jal	icache_enable
-- 
2.20.1

[U-Boot] [PATCH v3 06/11] riscv: add support for multi-hart systems

[Lukas Auer]

On RISC-V, all harts boot independently. To be able to run on a
multi-hart system, U-Boot must be extended with the functionality to
manage all harts in the system. All harts entering U-Boot are registered
in the available_harts mask stored in global data. A hart lottery system
as used in the Linux kernel selects the hart U-Boot runs on. All other
harts are halted. U-Boot can delegate functions to them using
smp_call_function().

Every hart has a valid pointer to the global data structure and a 8KiB
stack by default. The stack size is set with CONFIG_STACK_SIZE_SHIFT.

Signed-off-by: Lukas Auer <lukas.auer@aisec.fraunhofer.de>
Reviewed-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Tested-by: Bin Meng <bmeng.cn@gmail.com>
---

Changes in v3:
- Adjust patch to use the new location of the hart ID (register tp)

Changes in v2:
- Implement hart lottery to pick main hart to run U-Boot
- Remove CONFIG_MAIN_HART as it is not required anymore
- Register available harts in the available_harts mask

 arch/riscv/Kconfig           |   4 ++
 arch/riscv/cpu/cpu.c         |   9 ++-
 arch/riscv/cpu/start.S       | 134 ++++++++++++++++++++++++++++++++++-
 arch/riscv/include/asm/csr.h |   1 +
 arch/riscv/lib/asm-offsets.c |   1 +
 5 files changed, 147 insertions(+), 2 deletions(-)

diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index 9da609b33b..3a4470daf3 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -144,4 +144,8 @@ config SBI_IPI
 	default y if RISCV_SMODE
 	depends on SMP
 
+config STACK_SIZE_SHIFT
+	int
+	default 13
+
 endmenu
diff --git a/arch/riscv/cpu/cpu.c b/arch/riscv/cpu/cpu.c
index e662140427..c32de8a4c3 100644
--- a/arch/riscv/cpu/cpu.c
+++ b/arch/riscv/cpu/cpu.c
@@ -12,10 +12,17 @@
 #include <dm/uclass-internal.h>
 
 /*
- * prior_stage_fdt_address must be stored in the data section since it is used
+ * The variables here must be stored in the data section since they are used
  * before the bss section is available.
  */
 phys_addr_t prior_stage_fdt_address __attribute__((section(".data")));
+u32 hart_lottery __attribute__((section(".data"))) = 0;
+
+/*
+ * The main hart running U-Boot has acquired available_harts_lock until it has
+ * finished initialization of global data.
+ */
+u32 available_harts_lock = 1;
 
 static inline bool supports_extension(char ext)
 {
diff --git a/arch/riscv/cpu/start.S b/arch/riscv/cpu/start.S
index bcc0ff696d..f55b8cbc37 100644
--- a/arch/riscv/cpu/start.S
+++ b/arch/riscv/cpu/start.S
@@ -13,6 +13,7 @@
 #include <config.h>
 #include <common.h>
 #include <elf.h>
+#include <asm/csr.h>
 #include <asm/encoding.h>
 #include <generated/asm-offsets.h>
 
@@ -45,6 +46,23 @@ _start:
 	/* mask all interrupts */
 	csrw	MODE_PREFIX(ie), zero
 
+#ifdef CONFIG_SMP
+	/* check if hart is within range */
+	/* tp: hart id */
+	li	t0, CONFIG_NR_CPUS
+	bge	tp, t0, hart_out_of_bounds_loop
+#endif
+
+#ifdef CONFIG_SMP
+	/* set xSIE bit to receive IPIs */
+#ifdef CONFIG_RISCV_MMODE
+	li	t0, MIE_MSIE
+#else
+	li	t0, SIE_SSIE
+#endif
+	csrs	MODE_PREFIX(ie), t0
+#endif
+
 /*
  * Set stackpointer in internal/ex RAM to call board_init_f
  */
@@ -56,7 +74,30 @@ call_board_init_f:
 call_board_init_f_0:
 	mv	a0, sp
 	jal	board_init_f_alloc_reserve
+
+	/*
+	 * Set global data pointer here for all harts, uninitialized at this
+	 * point.
+	 */
+	mv	gp, a0
+
+	/* setup stack */
+#ifdef CONFIG_SMP
+	/* tp: hart id */
+	slli	t0, tp, CONFIG_STACK_SIZE_SHIFT
+	sub	sp, a0, t0
+#else
 	mv	sp, a0
+#endif
+
+	/*
+	 * Pick hart to initialize global data and run U-Boot. The other harts
+	 * wait for initialization to complete.
+	 */
+	la	t0, hart_lottery
+	li	s2, 1
+	amoswap.w s2, t1, 0(t0)
+	bnez	s2, wait_for_gd_init
 
 	la	t0, prior_stage_fdt_address
 	SREG	s1, 0(t0)
@@ -66,6 +107,33 @@ call_board_init_f_0:
 	/* save the boot hart id to global_data */
 	SREG	tp, GD_BOOT_HART(gp)
 
+	la	t0, available_harts_lock
+	fence	rw, w
+	amoswap.w zero, zero, 0(t0)
+
+wait_for_gd_init:
+	la	t0, available_harts_lock
+	li	t1, 1
+1:	amoswap.w t1, t1, 0(t0)
+	fence	r, rw
+	bnez	t1, 1b
+
+	/* register available harts in the available_harts mask */
+	li	t1, 1
+	sll	t1, t1, tp
+	LREG	t2, GD_AVAILABLE_HARTS(gp)
+	or	t2, t2, t1
+	SREG	t2, GD_AVAILABLE_HARTS(gp)
+
+	fence	rw, w
+	amoswap.w zero, zero, 0(t0)
+
+	/*
+	 * Continue on hart lottery winner, others branch to
+	 * secondary_hart_loop.
+	 */
+	bnez	s2, secondary_hart_loop
+
 	/* Enable cache */
 	jal	icache_enable
 	jal	dcache_enable
@@ -95,7 +163,14 @@ relocate_code:
  *Set up the stack
  */
 stack_setup:
+#ifdef CONFIG_SMP
+	/* tp: hart id */
+	slli	t0, tp, CONFIG_STACK_SIZE_SHIFT
+	sub	sp, s2, t0
+#else
 	mv	sp, s2
+#endif
+
 	la	t0, _start
 	sub	t6, s4, t0		/* t6 <- relocation offset */
 	beq	t0, s4, clear_bss	/* skip relocation */
@@ -175,13 +250,30 @@ clear_bss:
 	add	t0, t0, t6		/* t0 <- rel __bss_start in RAM */
 	la	t1, __bss_end		/* t1 <- rel __bss_end in FLASH */
 	add	t1, t1, t6		/* t1 <- rel __bss_end in RAM */
-	beq	t0, t1, call_board_init_r
+	beq	t0, t1, relocate_secondary_harts
 
 clbss_l:
 	SREG	zero, 0(t0)		/* clear loop... */
 	addi	t0, t0, REGBYTES
 	bne	t0, t1, clbss_l
 
+relocate_secondary_harts:
+#ifdef CONFIG_SMP
+	/* send relocation IPI */
+	la	t0, secondary_hart_relocate
+	add	a0, t0, t6
+
+	/* store relocation offset */
+	mv	s5, t6
+
+	mv	a1, s2
+	mv	a2, s3
+	jal	smp_call_function
+
+	/* restore relocation offset */
+	mv	t6, s5
+#endif
+
 /*
  * We are done. Do not return, instead branch to second part of board
  * initialization, now running from RAM.
@@ -202,3 +294,43 @@ call_board_init_r:
  * jump to it ...
  */
 	jr	t4			/* jump to board_init_r() */
+
+#ifdef CONFIG_SMP
+hart_out_of_bounds_loop:
+	/* Harts in this loop are out of bounds, increase CONFIG_NR_CPUS. */
+	wfi
+	j	hart_out_of_bounds_loop
+#endif
+
+#ifdef CONFIG_SMP
+/* SMP relocation entry */
+secondary_hart_relocate:
+	/* a1: new sp */
+	/* a2: new gd */
+	/* tp: hart id */
+
+	/* setup stack */
+	slli	t0, tp, CONFIG_STACK_SIZE_SHIFT
+	sub	sp, a1, t0
+
+	/* update global data pointer */
+	mv	gp, a2
+#endif
+
+secondary_hart_loop:
+	wfi
+
+#ifdef CONFIG_SMP
+	csrr	t0, MODE_PREFIX(ip)
+#ifdef CONFIG_RISCV_MMODE
+	andi	t0, t0, MIE_MSIE
+#else
+	andi	t0, t0, SIE_SSIE
+#endif
+	beqz	t0, secondary_hart_loop
+
+	mv	a0, tp
+	jal	handle_ipi
+#endif
+
+	j	secondary_hart_loop
diff --git a/arch/riscv/include/asm/csr.h b/arch/riscv/include/asm/csr.h
index 86136f542c..644e6baa15 100644
--- a/arch/riscv/include/asm/csr.h
+++ b/arch/riscv/include/asm/csr.h
@@ -46,6 +46,7 @@
 #endif
 
 /* Interrupt Enable and Interrupt Pending flags */
+#define MIE_MSIE	_AC(0x00000008, UL) /* Software Interrupt Enable */
 #define SIE_SSIE	_AC(0x00000002, UL) /* Software Interrupt Enable */
 #define SIE_STIE	_AC(0x00000020, UL) /* Timer Interrupt Enable */
 
diff --git a/arch/riscv/lib/asm-offsets.c b/arch/riscv/lib/asm-offsets.c
index e0b71f5691..f998402bd1 100644
--- a/arch/riscv/lib/asm-offsets.c
+++ b/arch/riscv/lib/asm-offsets.c
@@ -14,6 +14,7 @@
 int main(void)
 {
 	DEFINE(GD_BOOT_HART, offsetof(gd_t, arch.boot_hart));
+	DEFINE(GD_AVAILABLE_HARTS, offsetof(gd_t, arch.available_harts));
 
 	return 0;
 }
-- 
2.20.1

[U-Boot] [PATCH v3 07/11] riscv: boot images passed to bootm on all harts

[Lukas Auer]

Signed-off-by: Lukas Auer <lukas.auer@aisec.fraunhofer.de>
Reviewed-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Tested-by: Bin Meng <bmeng.cn@gmail.com>
---

Changes in v3: None
Changes in v2: None

 arch/riscv/lib/bootm.c | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/arch/riscv/lib/bootm.c b/arch/riscv/lib/bootm.c
index f36b8702ef..efbd3e23e7 100644
--- a/arch/riscv/lib/bootm.c
+++ b/arch/riscv/lib/bootm.c
@@ -13,6 +13,7 @@
 #include <image.h>
 #include <asm/byteorder.h>
 #include <asm/csr.h>
+#include <asm/smp.h>
 #include <dm/device.h>
 #include <dm/root.h>
 #include <u-boot/zlib.h>
@@ -81,6 +82,9 @@ static void boot_jump_linux(bootm_headers_t *images, int flag)
 {
 	void (*kernel)(ulong hart, void *dtb);
 	int fake = (flag & BOOTM_STATE_OS_FAKE_GO);
+#ifdef CONFIG_SMP
+	int ret;
+#endif
 
 	kernel = (void (*)(ulong, void *))images->ep;
 
@@ -92,8 +96,15 @@ static void boot_jump_linux(bootm_headers_t *images, int flag)
 	announce_and_cleanup(fake);
 
 	if (!fake) {
-		if (IMAGE_ENABLE_OF_LIBFDT && images->ft_len)
+		if (IMAGE_ENABLE_OF_LIBFDT && images->ft_len) {
+#ifdef CONFIG_SMP
+			ret = smp_call_function(images->ep,
+						(ulong)images->ft_addr, 0);
+			if (ret)
+				hang();
+#endif
 			kernel(gd->arch.boot_hart, images->ft_addr);
+		}
 	}
 }
 
-- 
2.20.1

[U-Boot] [PATCH v3 08/11] riscv: do not rely on hart ID passed by previous boot stage

[Lukas Auer]

RISC-V U-Boot expects the hart ID to be passed to it via register a0 by
the previous boot stage. Machine mode firmware such as BBL and OpenSBI
do this when starting their payload (U-Boot) in supervisor mode. If
U-Boot is running in machine mode, this task must be handled by the boot
ROM. Explicitly populate register a0 with the hart ID from the mhartid
CSR to avoid possible problems on RISC-V processors with a boot ROM that
does not handle this task.

Suggested-by: Rick Chen <rick@andestech.com>
Signed-off-by: Lukas Auer <lukas.auer@aisec.fraunhofer.de>
Reviewed-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Atish Patra <atish.patra@wdc.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Tested-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Rick Chen <rick@andestech.com>
Tested-by: Rick Chen <rick@andestech.com>
---

Changes in v3: None
Changes in v2:
- New patch to populate register a0 with the hart ID from the mhartid
CSR in machine-mode

 arch/riscv/cpu/start.S | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/riscv/cpu/start.S b/arch/riscv/cpu/start.S
index f55b8cbc37..5ac899b141 100644
--- a/arch/riscv/cpu/start.S
+++ b/arch/riscv/cpu/start.S
@@ -36,6 +36,10 @@
 .section .text
 .globl _start
 _start:
+#ifdef CONFIG_RISCV_MMODE
+	csrr	a0, mhartid
+#endif
+
 	/* save hart id and dtb pointer */
 	mv	tp, a0
 	mv	s1, a1
-- 
2.20.1

[U-Boot] [PATCH v3 09/11] riscv: hang if relocation of secondary harts fails

[Lukas Auer]

Print an error message and hang if smp_call_function() returns an error,
indicating that relocation of the secondary harts has failed.

Signed-off-by: Lukas Auer <lukas.auer@aisec.fraunhofer.de>
---

Changes in v3:
- New patch to hang if relocation of secondary harts fails

Changes in v2: None

 arch/riscv/cpu/start.S | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/arch/riscv/cpu/start.S b/arch/riscv/cpu/start.S
index 5ac899b141..a4433fbd6b 100644
--- a/arch/riscv/cpu/start.S
+++ b/arch/riscv/cpu/start.S
@@ -33,6 +33,10 @@
 #define SYM_SIZE		0x18
 #endif
 
+.section .data
+secondary_harts_relocation_error:
+	.ascii "Relocation of secondary harts has failed, error %d\n"
+
 .section .text
 .globl _start
 _start:
@@ -274,8 +278,15 @@ relocate_secondary_harts:
 	mv	a2, s3
 	jal	smp_call_function
 
+	/* hang if relocation of secondary harts has failed */
+	beqz	a0, 1f
+	mv	a1, a0
+	la	a0, secondary_harts_relocation_error
+	jal	printf
+	jal	hang
+
 	/* restore relocation offset */
-	mv	t6, s5
+1:	mv	t6, s5
 #endif
 
 /*
-- 
2.20.1

[U-Boot] [PATCH v3 10/11] riscv: fu540: enable SMP

[Lukas Auer]

Signed-off-by: Lukas Auer <lukas.auer@aisec.fraunhofer.de>
Reviewed-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
---

Changes in v3: None
Changes in v2:
- New patch to enable SMP on the SiFive FU540, which was previously sent
independently

 board/sifive/fu540/Kconfig | 1 +
 1 file changed, 1 insertion(+)

diff --git a/board/sifive/fu540/Kconfig b/board/sifive/fu540/Kconfig
index 6be3d88144..f46437901d 100644
--- a/board/sifive/fu540/Kconfig
+++ b/board/sifive/fu540/Kconfig
@@ -38,5 +38,6 @@ config BOARD_SPECIFIC_OPTIONS # dummy
 	imply PHY_LIB
 	imply PHY_MSCC
 	imply SIFIVE_SERIAL
+	imply SMP
 
 endif
-- 
2.20.1

[U-Boot] [PATCH v3 11/11] riscv: qemu: enable SMP

[Lukas Auer]

Signed-off-by: Lukas Auer <lukas.auer@aisec.fraunhofer.de>
Reviewed-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Tested-by: Bin Meng <bmeng.cn@gmail.com>
---

Changes in v3: None
Changes in v2: None

 board/emulation/qemu-riscv/Kconfig | 1 +
 1 file changed, 1 insertion(+)

diff --git a/board/emulation/qemu-riscv/Kconfig b/board/emulation/qemu-riscv/Kconfig
index 88d07d568e..cf057e7de6 100644
--- a/board/emulation/qemu-riscv/Kconfig
+++ b/board/emulation/qemu-riscv/Kconfig
@@ -34,5 +34,6 @@ config BOARD_SPECIFIC_OPTIONS # dummy
 	imply BOARD_LATE_INIT
 	imply OF_BOARD_SETUP
 	imply SIFIVE_SERIAL
+	imply SMP
 
 endif
-- 
2.20.1

[U-Boot] [PATCH v3 05/11] riscv: save hart ID in register tp instead of s0

[Bin Meng]

On Mon, Mar 18, 2019 at 2:29 AM Lukas Auer
<lukas.auer@aisec.fraunhofer.de> wrote:
>
> The hart ID passed by the previous boot stage is currently stored in
> register s0. If we divert the control flow inside a function, which is
> required as part of multi-hart support, the function epilog may not be
> called, clobbering register s0. Save the hart ID in the unallocatable
> register tp instead to protect the hart ID.
>
> Signed-off-by: Lukas Auer <lukas.auer@aisec.fraunhofer.de>
> ---
>
> Changes in v3:
> - New patch to save the hart ID in register tp instead of s0
>
> Changes in v2: None
>
>  arch/riscv/cpu/start.S | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>

Reviewed-by: Bin Meng <bmeng.cn@gmail.com>

[U-Boot] [PATCH v3 05/11] riscv: save hart ID in register tp instead of s0

[Rick Chen]

> > From: Lukas Auer [mailto:lukas.auer at aisec.fraunhofer.de]
> > Sent: Monday, March 18, 2019 2:29 AM
> > To: u-boot at lists.denx.de
> > Cc: Anup Patel; Andreas Schwab; Bin Meng; Atish Patra; Palmer Dabbelt; Lukas
> > Auer; Atish Patra; Anup Patel; Rick Jian-Zhi Chen(陳建志)
> > Subject: [PATCH v3 05/11] riscv: save hart ID in register tp instead of s0
> >
> > The hart ID passed by the previous boot stage is currently stored in register s0. If
> > we divert the control flow inside a function, which is required as part of
> > multi-hart support, the function epilog may not be called, clobbering register s0.
> > Save the hart ID in the unallocatable register tp instead to protect the hart ID.
> >
> > Signed-off-by: Lukas Auer <lukas.auer@aisec.fraunhofer.de>
> > ---
> >
> > Changes in v3:
> > - New patch to save the hart ID in register tp instead of s0
> >
> > Changes in v2: None
> >
> >  arch/riscv/cpu/start.S | 4 ++--
> >  1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/arch/riscv/cpu/start.S b/arch/riscv/cpu/start.S index
> > a30f6f7194..bcc0ff696d 100644
> > --- a/arch/riscv/cpu/start.S
> > +++ b/arch/riscv/cpu/start.S
> > @@ -36,7 +36,7 @@
> >  .globl _start
> >  _start:
> >       /* save hart id and dtb pointer */
> > -     mv      s0, a0
> > +     mv      tp, a0
> >       mv      s1, a1
> >
> >       la      t0, trap_entry
> > @@ -64,7 +64,7 @@ call_board_init_f_0:
> >       jal     board_init_f_init_reserve
> >
> >       /* save the boot hart id to global_data */
> > -     SREG    s0, GD_BOOT_HART(gp)
> > +     SREG    tp, GD_BOOT_HART(gp)
> >
> >       /* Enable cache */
> >       jal     icache_enable

Reviewed-by: Rick Chen <rick@andestech.com>

[U-Boot] [PATCH v3 09/11] riscv: hang if relocation of secondary harts fails

[Bin Meng]

On Mon, Mar 18, 2019 at 2:29 AM Lukas Auer
<lukas.auer@aisec.fraunhofer.de> wrote:
>
> Print an error message and hang if smp_call_function() returns an error,
> indicating that relocation of the secondary harts has failed.
>
> Signed-off-by: Lukas Auer <lukas.auer@aisec.fraunhofer.de>
> ---
>
> Changes in v3:
> - New patch to hang if relocation of secondary harts fails
>
> Changes in v2: None
>
>  arch/riscv/cpu/start.S | 13 ++++++++++++-
>  1 file changed, 12 insertions(+), 1 deletion(-)
>

Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Tested-by: Bin Meng <bmeng.cn@gmail.com>

[U-Boot] [PATCH v3 05/11] riscv: save hart ID in register tp instead of s0

[Anup Patel]

> -----Original Message-----
> From: Lukas Auer <lukas.auer@aisec.fraunhofer.de>
> Sent: Sunday, March 17, 2019 11:59 PM
> To: u-boot at lists.denx.de
> Cc: Anup Patel <Anup.Patel@wdc.com>; Andreas Schwab
> <schwab@suse.de>; Bin Meng <bmeng.cn@gmail.com>; Atish Patra
> <Atish.Patra@wdc.com>; Palmer Dabbelt <palmer@sifive.com>; Lukas Auer
> <lukas.auer@aisec.fraunhofer.de>; Atish Patra <Atish.Patra@wdc.com>;
> Anup Patel <anup@brainfault.org>; Rick Chen <rick@andestech.com>
> Subject: [PATCH v3 05/11] riscv: save hart ID in register tp instead of s0
> 
> The hart ID passed by the previous boot stage is currently stored in register
> s0. If we divert the control flow inside a function, which is required as part of
> multi-hart support, the function epilog may not be called, clobbering register
> s0. Save the hart ID in the unallocatable register tp instead to protect the hart
> ID.
> 
> Signed-off-by: Lukas Auer <lukas.auer@aisec.fraunhofer.de>
> ---
> 
> Changes in v3:
> - New patch to save the hart ID in register tp instead of s0
> 
> Changes in v2: None
> 
>  arch/riscv/cpu/start.S | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/riscv/cpu/start.S b/arch/riscv/cpu/start.S index
> a30f6f7194..bcc0ff696d 100644
> --- a/arch/riscv/cpu/start.S
> +++ b/arch/riscv/cpu/start.S
> @@ -36,7 +36,7 @@
>  .globl _start
>  _start:
>  	/* save hart id and dtb pointer */
> -	mv	s0, a0
> +	mv	tp, a0
>  	mv	s1, a1
> 
>  	la	t0, trap_entry
> @@ -64,7 +64,7 @@ call_board_init_f_0:
>  	jal	board_init_f_init_reserve
> 
>  	/* save the boot hart id to global_data */
> -	SREG	s0, GD_BOOT_HART(gp)
> +	SREG	tp, GD_BOOT_HART(gp)
> 
>  	/* Enable cache */
>  	jal	icache_enable
> --
> 2.20.1

Reviewed-by: Anup Patel <anup.patel@wdc.com>

[U-Boot] [PATCH v3 09/11] riscv: hang if relocation of secondary harts fails

[Anup Patel]

> -----Original Message-----
> From: Lukas Auer <lukas.auer@aisec.fraunhofer.de>
> Sent: Sunday, March 17, 2019 11:59 PM
> To: u-boot at lists.denx.de
> Cc: Anup Patel <Anup.Patel@wdc.com>; Andreas Schwab
> <schwab@suse.de>; Bin Meng <bmeng.cn@gmail.com>; Atish Patra
> <Atish.Patra@wdc.com>; Palmer Dabbelt <palmer@sifive.com>; Lukas Auer
> <lukas.auer@aisec.fraunhofer.de>; Atish Patra <Atish.Patra@wdc.com>;
> Anup Patel <anup@brainfault.org>; Rick Chen <rick@andestech.com>
> Subject: [PATCH v3 09/11] riscv: hang if relocation of secondary harts fails
> 
> Print an error message and hang if smp_call_function() returns an error,
> indicating that relocation of the secondary harts has failed.
> 
> Signed-off-by: Lukas Auer <lukas.auer@aisec.fraunhofer.de>
> ---
> 
> Changes in v3:
> - New patch to hang if relocation of secondary harts fails
> 
> Changes in v2: None
> 
>  arch/riscv/cpu/start.S | 13 ++++++++++++-
>  1 file changed, 12 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/riscv/cpu/start.S b/arch/riscv/cpu/start.S index
> 5ac899b141..a4433fbd6b 100644
> --- a/arch/riscv/cpu/start.S
> +++ b/arch/riscv/cpu/start.S
> @@ -33,6 +33,10 @@
>  #define SYM_SIZE		0x18
>  #endif
> 
> +.section .data
> +secondary_harts_relocation_error:
> +	.ascii "Relocation of secondary harts has failed, error %d\n"
> +
>  .section .text
>  .globl _start
>  _start:
> @@ -274,8 +278,15 @@ relocate_secondary_harts:
>  	mv	a2, s3
>  	jal	smp_call_function
> 
> +	/* hang if relocation of secondary harts has failed */
> +	beqz	a0, 1f
> +	mv	a1, a0
> +	la	a0, secondary_harts_relocation_error
> +	jal	printf
> +	jal	hang
> +
>  	/* restore relocation offset */
> -	mv	t6, s5
> +1:	mv	t6, s5
>  #endif
> 
>  /*
> --
> 2.20.1

Reviewed-by: Anup Patel <anup.patel@wdc.com>

[U-Boot] [PATCH v3 00/11] SMP support for RISC-V

[Palmer Dabbelt]

On Sun, 17 Mar 2019 11:28:31 PDT (-0700), lukas.auer at aisec.fraunhofer.de wrote:
> This patch series adds SMP support for RISC-V to U-Boot. It allows
> U-Boot to run on multi-hart systems (hart is the RISC-V terminology for
> hardware thread). Images passed to bootm will be started on all harts.
> The bootm command is currently the only one that will boot images on all
> harts, bootefi is not yet supported.
>
> The patches have been successfully tested on both QEMU (machine and
> supervisor mode) and the HiFive Unleashed board (supervisor mode), using
> BBL and OpenSBI.
> Mainline QEMU requires two patches [1, 2] to run in this configuration.
> Patch [1] has been dropped and will be replaced with a U-Boot patch.
>
> [1]: https://patchwork.ozlabs.org/patch/1039493/

As far as I understand it we're taking a different approach here, so this patch 
won't be going in.

> [2]: https://patchwork.ozlabs.org/patch/1039082/

This should be in rc0, LMK if I screwed something up.

Thanks for the patches, and also for testing on the board :)

> Changes in v3:
> - Print error if riscv_send_ipi() fails
> - Adjust error message for failures of riscv_clear_ipi() to match error
> message for failures of riscv_send_ipi()
> - New patch to save the hart ID in register tp instead of s0
> - Adjust patch to use the new location of the hart ID (register tp)
> - New patch to hang if relocation of secondary harts fails
>
> Changes in v2:
> - Remove unneeded quotes from NR_CPUS Kconfig entry
> - Move memory barrier from send_ipi_many() to handle_ipi()
> - Add check in send_ipi_many so that IPIs are only sent to available
> harts as indicated by the available_harts mask
> - Implement hart lottery to pick main hart to run U-Boot
> - Remove CONFIG_MAIN_HART as it is not required anymore
> - Register available harts in the available_harts mask
> - New patch to populate register a0 with the hart ID from the mhartid
> CSR in machine-mode
> - New patch to enable SMP on the SiFive FU540, which was previously sent
> independently
>
> Lukas Auer (11):
>   riscv: add infrastructure for calling functions on other harts
>   riscv: import the supervisor binary interface header file
>   riscv: implement IPI platform functions using SBI
>   riscv: delay initialization of caches and debug UART
>   riscv: save hart ID in register tp instead of s0
>   riscv: add support for multi-hart systems
>   riscv: boot images passed to bootm on all harts
>   riscv: do not rely on hart ID passed by previous boot stage
>   riscv: hang if relocation of secondary harts fails
>   riscv: fu540: enable SMP
>   riscv: qemu: enable SMP
>
>  arch/riscv/Kconfig                   |  28 +++++
>  arch/riscv/cpu/cpu.c                 |   9 +-
>  arch/riscv/cpu/start.S               | 167 +++++++++++++++++++++++++--
>  arch/riscv/include/asm/csr.h         |   1 +
>  arch/riscv/include/asm/global_data.h |   6 +
>  arch/riscv/include/asm/sbi.h         |  94 +++++++++++++++
>  arch/riscv/include/asm/smp.h         |  53 +++++++++
>  arch/riscv/lib/Makefile              |   2 +
>  arch/riscv/lib/asm-offsets.c         |   1 +
>  arch/riscv/lib/bootm.c               |  13 ++-
>  arch/riscv/lib/sbi_ipi.c             |  25 ++++
>  arch/riscv/lib/smp.c                 | 118 +++++++++++++++++++
>  board/emulation/qemu-riscv/Kconfig   |   1 +
>  board/sifive/fu540/Kconfig           |   1 +
>  14 files changed, 507 insertions(+), 12 deletions(-)
>  create mode 100644 arch/riscv/include/asm/sbi.h
>  create mode 100644 arch/riscv/include/asm/smp.h
>  create mode 100644 arch/riscv/lib/sbi_ipi.c
>  create mode 100644 arch/riscv/lib/smp.c

[U-Boot] [PATCH v3 00/11] SMP support for RISC-V

[Auer, Lukas]

On Wed, 2019-03-20 at 05:37 -0700, Palmer Dabbelt wrote:
> On Sun, 17 Mar 2019 11:28:31 PDT (-0700), 
> lukas.auer at aisec.fraunhofer.de wrote:
> > This patch series adds SMP support for RISC-V to U-Boot. It allows
> > U-Boot to run on multi-hart systems (hart is the RISC-V terminology
> > for
> > hardware thread). Images passed to bootm will be started on all
> > harts.
> > The bootm command is currently the only one that will boot images
> > on all
> > harts, bootefi is not yet supported.
> > 
> > The patches have been successfully tested on both QEMU (machine and
> > supervisor mode) and the HiFive Unleashed board (supervisor mode),
> > using
> > BBL and OpenSBI.
> > Mainline QEMU requires two patches [1, 2] to run in this
> > configuration.
> > Patch [1] has been dropped and will be replaced with a U-Boot
> > patch.
> > 
> > [1]: https://patchwork.ozlabs.org/patch/1039493/
> 
> As far as I understand it we're taking a different approach here, so
> this patch 
> won't be going in.
> 
> > [2]: https://patchwork.ozlabs.org/patch/1039082/
> 
> This should be in rc0, LMK if I screwed something up.
> 
> Thanks for the patches, and also for testing on the board :)
> 

Everything looks good, thanks for merging the patch!

U-Boot with the SMP patches now runs in supervisor mode on mainline
QEMU. I will send a U-Boot patch later this week to get it running in
machine mode on mainline QEMU as well.

Thanks,
Lukas

> > Changes in v3:
> > - Print error if riscv_send_ipi() fails
> > - Adjust error message for failures of riscv_clear_ipi() to match
> > error
> > message for failures of riscv_send_ipi()
> > - New patch to save the hart ID in register tp instead of s0
> > - Adjust patch to use the new location of the hart ID (register tp)
> > - New patch to hang if relocation of secondary harts fails
> > 
> > Changes in v2:
> > - Remove unneeded quotes from NR_CPUS Kconfig entry
> > - Move memory barrier from send_ipi_many() to handle_ipi()
> > - Add check in send_ipi_many so that IPIs are only sent to
> > available
> > harts as indicated by the available_harts mask
> > - Implement hart lottery to pick main hart to run U-Boot
> > - Remove CONFIG_MAIN_HART as it is not required anymore
> > - Register available harts in the available_harts mask
> > - New patch to populate register a0 with the hart ID from the
> > mhartid
> > CSR in machine-mode
> > - New patch to enable SMP on the SiFive FU540, which was previously
> > sent
> > independently
> > 
> > Lukas Auer (11):
> >   riscv: add infrastructure for calling functions on other harts
> >   riscv: import the supervisor binary interface header file
> >   riscv: implement IPI platform functions using SBI
> >   riscv: delay initialization of caches and debug UART
> >   riscv: save hart ID in register tp instead of s0
> >   riscv: add support for multi-hart systems
> >   riscv: boot images passed to bootm on all harts
> >   riscv: do not rely on hart ID passed by previous boot stage
> >   riscv: hang if relocation of secondary harts fails
> >   riscv: fu540: enable SMP
> >   riscv: qemu: enable SMP
> > 
> >  arch/riscv/Kconfig                   |  28 +++++
> >  arch/riscv/cpu/cpu.c                 |   9 +-
> >  arch/riscv/cpu/start.S               | 167
> > +++++++++++++++++++++++++--
> >  arch/riscv/include/asm/csr.h         |   1 +
> >  arch/riscv/include/asm/global_data.h |   6 +
> >  arch/riscv/include/asm/sbi.h         |  94 +++++++++++++++
> >  arch/riscv/include/asm/smp.h         |  53 +++++++++
> >  arch/riscv/lib/Makefile              |   2 +
> >  arch/riscv/lib/asm-offsets.c         |   1 +
> >  arch/riscv/lib/bootm.c               |  13 ++-
> >  arch/riscv/lib/sbi_ipi.c             |  25 ++++
> >  arch/riscv/lib/smp.c                 | 118 +++++++++++++++++++
> >  board/emulation/qemu-riscv/Kconfig   |   1 +
> >  board/sifive/fu540/Kconfig           |   1 +
> >  14 files changed, 507 insertions(+), 12 deletions(-)
> >  create mode 100644 arch/riscv/include/asm/sbi.h
> >  create mode 100644 arch/riscv/include/asm/smp.h
> >  create mode 100644 arch/riscv/lib/sbi_ipi.c
> >  create mode 100644 arch/riscv/lib/smp.c

[U-Boot] [PATCH v3 00/11] SMP support for RISC-V

[Troy Benjegerdes]

On Sun, Mar 17, 2019 at 07:28:31PM +0100, Lukas Auer wrote:
> This patch series adds SMP support for RISC-V to U-Boot. It allows
> U-Boot to run on multi-hart systems (hart is the RISC-V terminology for
> hardware thread). Images passed to bootm will be started on all harts.
> The bootm command is currently the only one that will boot images on all
> harts, bootefi is not yet supported.
> 
> The patches have been successfully tested on both QEMU (machine and
> supervisor mode) and the HiFive Unleashed board (supervisor mode), using
> BBL and OpenSBI.

Can you describe the test configuration and boot flow a little more, or post an
SDcard image that boots with the switches as shown in the readme at [1]

I don't see any board-specific memory initialization code anywhere, so I assume
you are still using the original SiFive FSBL, and not the u-boot version that
includes the memory init code [2]

[1] https://github.com/sifive/freedom-u-sdk
[2] https://github.com/sifive/HiFive_U-Boot 

> Mainline QEMU requires two patches [1, 2] to run in this configuration.
> Patch [1] has been dropped and will be replaced with a U-Boot patch.
> 
> [1]: https://patchwork.ozlabs.org/patch/1039493/
> [2]: https://patchwork.ozlabs.org/patch/1039082/
> 
> Changes in v3:
> - Print error if riscv_send_ipi() fails
> - Adjust error message for failures of riscv_clear_ipi() to match error
> message for failures of riscv_send_ipi()
> - New patch to save the hart ID in register tp instead of s0
> - Adjust patch to use the new location of the hart ID (register tp)
> - New patch to hang if relocation of secondary harts fails
> 
> Changes in v2:
> - Remove unneeded quotes from NR_CPUS Kconfig entry
> - Move memory barrier from send_ipi_many() to handle_ipi()
> - Add check in send_ipi_many so that IPIs are only sent to available
> harts as indicated by the available_harts mask
> - Implement hart lottery to pick main hart to run U-Boot
> - Remove CONFIG_MAIN_HART as it is not required anymore
> - Register available harts in the available_harts mask
> - New patch to populate register a0 with the hart ID from the mhartid
> CSR in machine-mode
> - New patch to enable SMP on the SiFive FU540, which was previously sent
> independently
> 
> Lukas Auer (11):
>   riscv: add infrastructure for calling functions on other harts
>   riscv: import the supervisor binary interface header file
>   riscv: implement IPI platform functions using SBI
>   riscv: delay initialization of caches and debug UART
>   riscv: save hart ID in register tp instead of s0
>   riscv: add support for multi-hart systems
>   riscv: boot images passed to bootm on all harts
>   riscv: do not rely on hart ID passed by previous boot stage
>   riscv: hang if relocation of secondary harts fails
>   riscv: fu540: enable SMP
>   riscv: qemu: enable SMP
> 
>  arch/riscv/Kconfig                   |  28 +++++
>  arch/riscv/cpu/cpu.c                 |   9 +-
>  arch/riscv/cpu/start.S               | 167 +++++++++++++++++++++++++--
>  arch/riscv/include/asm/csr.h         |   1 +
>  arch/riscv/include/asm/global_data.h |   6 +
>  arch/riscv/include/asm/sbi.h         |  94 +++++++++++++++
>  arch/riscv/include/asm/smp.h         |  53 +++++++++
>  arch/riscv/lib/Makefile              |   2 +
>  arch/riscv/lib/asm-offsets.c         |   1 +
>  arch/riscv/lib/bootm.c               |  13 ++-
>  arch/riscv/lib/sbi_ipi.c             |  25 ++++
>  arch/riscv/lib/smp.c                 | 118 +++++++++++++++++++
>  board/emulation/qemu-riscv/Kconfig   |   1 +
>  board/sifive/fu540/Kconfig           |   1 +
>  14 files changed, 507 insertions(+), 12 deletions(-)
>  create mode 100644 arch/riscv/include/asm/sbi.h
>  create mode 100644 arch/riscv/include/asm/smp.h
>  create mode 100644 arch/riscv/lib/sbi_ipi.c
>  create mode 100644 arch/riscv/lib/smp.c
> 
> -- 
> 2.20.1
> 
> _______________________________________________
> U-Boot mailing list
> U-Boot at lists.denx.de
> https://lists.denx.de/listinfo/u-boot

[U-Boot] [PATCH v3 00/11] SMP support for RISC-V

[Bin Meng]

On Thu, Mar 21, 2019 at 11:39 PM Troy Benjegerdes <hozer@hozed.org> wrote:
>
> On Sun, Mar 17, 2019 at 07:28:31PM +0100, Lukas Auer wrote:
> > This patch series adds SMP support for RISC-V to U-Boot. It allows
> > U-Boot to run on multi-hart systems (hart is the RISC-V terminology for
> > hardware thread). Images passed to bootm will be started on all harts.
> > The bootm command is currently the only one that will boot images on all
> > harts, bootefi is not yet supported.
> >
> > The patches have been successfully tested on both QEMU (machine and
> > supervisor mode) and the HiFive Unleashed board (supervisor mode), using
> > BBL and OpenSBI.
>
> Can you describe the test configuration and boot flow a little more, or post an
> SDcard image that boots with the switches as shown in the readme at [1]
>
> I don't see any board-specific memory initialization code anywhere, so I assume
> you are still using the original SiFive FSBL, and not the u-boot version that
> includes the memory init code [2]
>

Correct. Mainline U-Boot on the FU540 board runs on S-mode currently.
You can refer to documentation doc/README.sifive-fu540

> [1] https://github.com/sifive/freedom-u-sdk
> [2] https://github.com/sifive/HiFive_U-Boot
>

Regards,
Bin

[U-Boot] [PATCH v3 00/11] SMP support for RISC-V

[Atish Patra]

On 3/21/19 4:06 PM, Bin Meng wrote:
> On Thu, Mar 21, 2019 at 11:39 PM Troy Benjegerdes <hozer@hozed.org> wrote:
>>
>> On Sun, Mar 17, 2019 at 07:28:31PM +0100, Lukas Auer wrote:
>>> This patch series adds SMP support for RISC-V to U-Boot. It allows
>>> U-Boot to run on multi-hart systems (hart is the RISC-V terminology for
>>> hardware thread). Images passed to bootm will be started on all harts.
>>> The bootm command is currently the only one that will boot images on all
>>> harts, bootefi is not yet supported.
>>>
>>> The patches have been successfully tested on both QEMU (machine and
>>> supervisor mode) and the HiFive Unleashed board (supervisor mode), using
>>> BBL and OpenSBI.
>>
>> Can you describe the test configuration and boot flow a little more, or post an
>> SDcard image that boots with the switches as shown in the readme at [1]
>>
>> I don't see any board-specific memory initialization code anywhere, so I assume
>> you are still using the original SiFive FSBL, and not the u-boot version that
>> includes the memory init code [2]
>>
> 
> Correct. Mainline U-Boot on the FU540 board runs on S-mode currently.
> You can refer to documentation doc/README.sifive-fu540
> 

To add Bin's comment, the boot flow described in README.sifive-fu540 is

ZSBL->FSBL->OpenSBI/BBL->U-Boot(S Mode)->Linux

FYI: For BBL, you need to hack U-Boot to add serial console in DT.

IMHO, we should avoid forks and use upstream code as much as possible.

The memory initialization patches in [2] were never upstreamed. It would 
be great if that can upstream them so that we can replace FSBL as well. 
U-Boot SPL support for RISC-V would even be better.

Regards,
Atish
>> [1] https://github.com/sifive/freedom-u-sdk
>> [2] https://github.com/sifive/HiFive_U-Boot
>>
> 
> Regards,
> Bin
> _______________________________________________
> U-Boot mailing list
> U-Boot at lists.denx.de
> https://lists.denx.de/listinfo/u-boot
> 

[U-Boot] [PATCH v3 00/11] SMP support for RISC-V

[Padmarao Begari]

I think, the boot flow explained above is supported the sifive fu540 board
default boot mode.
if we want to select debug mode, then, does this patches work with the
u-boot to TFTP booting(dhcp, bootp) in debug mode?

Regards
Padmarao

On Fri, Mar 22, 2019 at 4:47 AM Atish Patra <atish.patra@wdc.com> wrote:

> On 3/21/19 4:06 PM, Bin Meng wrote:
> > On Thu, Mar 21, 2019 at 11:39 PM Troy Benjegerdes <hozer@hozed.org>
> wrote:
> >>
> >> On Sun, Mar 17, 2019 at 07:28:31PM +0100, Lukas Auer wrote:
> >>> This patch series adds SMP support for RISC-V to U-Boot. It allows
> >>> U-Boot to run on multi-hart systems (hart is the RISC-V terminology for
> >>> hardware thread). Images passed to bootm will be started on all harts.
> >>> The bootm command is currently the only one that will boot images on
> all
> >>> harts, bootefi is not yet supported.
> >>>
> >>> The patches have been successfully tested on both QEMU (machine and
> >>> supervisor mode) and the HiFive Unleashed board (supervisor mode),
> using
> >>> BBL and OpenSBI.
> >>
> >> Can you describe the test configuration and boot flow a little more, or
> post an
> >> SDcard image that boots with the switches as shown in the readme at [1]
> >>
> >> I don't see any board-specific memory initialization code anywhere, so
> I assume
> >> you are still using the original SiFive FSBL, and not the u-boot
> version that
> >> includes the memory init code [2]
> >>
> >
> > Correct. Mainline U-Boot on the FU540 board runs on S-mode currently.
> > You can refer to documentation doc/README.sifive-fu540
> >
>
> To add Bin's comment, the boot flow described in README.sifive-fu540 is
>
> ZSBL->FSBL->OpenSBI/BBL->U-Boot(S Mode)->Linux
>
> FYI: For BBL, you need to hack U-Boot to add serial console in DT.
>
> IMHO, we should avoid forks and use upstream code as much as possible.
>
> The memory initialization patches in [2] were never upstreamed. It would
> be great if that can upstream them so that we can replace FSBL as well.
> U-Boot SPL support for RISC-V would even be better.
>
> Regards,
> Atish
> >> [1] https://github.com/sifive/freedom-u-sdk
> >> [2] https://github.com/sifive/HiFive_U-Boot
> >>
> >
> > Regards,
> > Bin
> > _______________________________________________
> > U-Boot mailing list
> > U-Boot at lists.denx.de
> > https://lists.denx.de/listinfo/u-boot
> >
>
> _______________________________________________
> U-Boot mailing list
> U-Boot at lists.denx.de
> https://lists.denx.de/listinfo/u-boot
>