Merge remote-tracking branch 'remotes/alistair/tags/pull-riscv-to-app…

…ly-20210715' into staging

Fourth RISC-V PR for 6.1 release

 - Code cleanups
 - Documentation improvements
 - Hypervisor extension improvements with hideleg and hedeleg
 - sifive_u fixes
 - OpenTitan register layout updates
 - Fix coverity issue

# gpg: Signature made Thu 15 Jul 2021 08:14:00 BST
# gpg:                using RSA key F6C4AC46D4934868D3B8CE8F21E10D29DF977054
# gpg: Good signature from "Alistair Francis <alistair@alistair23.me>" [full]
# Primary key fingerprint: F6C4 AC46 D493 4868 D3B8  CE8F 21E1 0D29 DF97 7054

* remotes/alistair/tags/pull-riscv-to-apply-20210715:
  hw/riscv/boot: Check the error of fdt_pack()
  hw/riscv: opentitan: Add the flash alias
  hw/riscv: opentitan: Add the unimplement rv_core_ibex_peri
  char: ibex_uart: Update the register layout
  hw/riscv: sifive_u: Make sure firmware info is 8-byte aligned
  hw/riscv: sifive_u: Correct the CLINT timebase frequency
  docs/system: riscv: Update Microchip Icicle Kit for direct kernel boot
  target/riscv: hardwire bits in hideleg and hedeleg
  docs/system: riscv: Add documentation for virt machine
  docs/system: riscv: Fix CLINT name in the sifive_u doc
  target/riscv: csr: Remove redundant check in fp csr read/write routines
  target/riscv: pmp: Fix some typos

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

docs/system/riscv/microchip-icicle-kit.rst

@@ -47,13 +47,13 @@ The user provided DTB should have the following requirements:
 
 QEMU follows below truth table to select which payload to execute:
 
-=====  ========== =======
--bios     -kernel payload
-=====  ========== =======
-    N           N     HSS
-    Y  don't care     HSS
-    N           Y  kernel
-=====  ========== =======
+===== ========== ========== =======
+-bios    -kernel       -dtb payload
+===== ========== ========== =======
+    N          N don't care     HSS
+    Y don't care don't care     HSS
+    N          Y          Y  kernel
+===== ========== ========== =======
 
 The memory is set to 1537 MiB by default which is the minimum required high
 memory size by HSS. A sanity check on ram size is performed in the machine
@@ -106,4 +106,44 @@ HSS output is on the first serial port (stdio) and U-Boot outputs on the
 second serial port. U-Boot will automatically load the Linux kernel from
 the SD card image.
 
+Direct Kernel Boot
+------------------
+
+Sometimes we just want to test booting a new kernel, and transforming the
+kernel image to the format required by the HSS bootflow is tedious. We can
+use '-kernel' for direct kernel booting just like other RISC-V machines do.
+
+In this mode, the OpenSBI fw_dynamic BIOS image for 'generic' platform is
+used to boot an S-mode payload like U-Boot or OS kernel directly.
+
+For example, the following commands show building a U-Boot image from U-Boot
+mainline v2021.07 for the Microchip Icicle Kit board:
+
+.. code-block:: bash
+
+  $ export CROSS_COMPILE=riscv64-linux-
+  $ make microchip_mpfs_icicle_defconfig
+
+Then we can boot the machine by:
+
+.. code-block:: bash
+
+  $ qemu-system-riscv64 -M microchip-icicle-kit -smp 5 -m 2G \
+      -sd path/to/sdcard.img \
+      -nic user,model=cadence_gem \
+      -nic tap,ifname=tap,model=cadence_gem,script=no \
+      -display none -serial stdio \
+      -kernel path/to/u-boot/build/dir/u-boot.bin \
+      -dtb path/to/u-boot/build/dir/u-boot.dtb
+
+CAVEATS:
+
+* Check the "stdout-path" property in the /chosen node in the DTB to determine
+  which serial port is used for the serial console, e.g.: if the console is set
+  to the second serial port, change to use "-serial null -serial stdio".
+* The default U-Boot configuration uses CONFIG_OF_SEPARATE hence the ELF image
+  ``u-boot`` cannot be passed to "-kernel" as it does not contain the DTB hence
+  ``u-boot.bin`` has to be used which does contain one. To use the ELF image,
+  we need to change to CONFIG_OF_EMBED or CONFIG_OF_PRIOR_STAGE.
+
 .. _HSS: https://github.com/polarfire-soc/hart-software-services

docs/system/riscv/sifive_u.rst

@@ -11,7 +11,7 @@ The ``sifive_u`` machine supports the following devices:
 
 * 1 E51 / E31 core
 * Up to 4 U54 / U34 cores
-* Core Level Interruptor (CLINT)
+* Core Local Interruptor (CLINT)
 * Platform-Level Interrupt Controller (PLIC)
 * Power, Reset, Clock, Interrupt (PRCI)
 * L2 Loosely Integrated Memory (L2-LIM)

docs/system/riscv/virt.rst

@@ -0,0 +1,138 @@
+'virt' Generic Virtual Platform (``virt``)
+==========================================
+
+The `virt` board is a platform which does not correspond to any real hardware;
+it is designed for use in virtual machines. It is the recommended board type
+if you simply want to run a guest such as Linux and do not care about
+reproducing the idiosyncrasies and limitations of a particular bit of
+real-world hardware.
+
+Supported devices
+-----------------
+
+The ``virt`` machine supports the following devices:
+
+* Up to 8 generic RV32GC/RV64GC cores, with optional extensions
+* Core Local Interruptor (CLINT)
+* Platform-Level Interrupt Controller (PLIC)
+* CFI parallel NOR flash memory
+* 1 NS16550 compatible UART
+* 1 Google Goldfish RTC
+* 1 SiFive Test device
+* 8 virtio-mmio transport devices
+* 1 generic PCIe host bridge
+* The fw_cfg device that allows a guest to obtain data from QEMU
+
+Note that the default CPU is a generic RV32GC/RV64GC. Optional extensions
+can be enabled via command line parameters, e.g.: ``-cpu rv64,x-h=true``
+enables the hypervisor extension for RV64.
+
+Hardware configuration information
+----------------------------------
+
+The ``virt`` machine automatically generates a device tree blob ("dtb")
+which it passes to the guest, if there is no ``-dtb`` option. This provides
+information about the addresses, interrupt lines and other configuration of
+the various devices in the system. Guest software should discover the devices
+that are present in the generated DTB.
+
+If users want to provide their own DTB, they can use the ``-dtb`` option.
+These DTBs should have the following requirements:
+
+* The number of subnodes of the /cpus node should match QEMU's ``-smp`` option
+* The /memory reg size should match QEMU’s selected ram_size via ``-m``
+* Should contain a node for the CLINT device with a compatible string
+  "riscv,clint0" if using with OpenSBI BIOS images
+
+Boot options
+------------
+
+The ``virt`` machine can start using the standard -kernel functionality
+for loading a Linux kernel, a VxWorks kernel, an S-mode U-Boot bootloader
+with the default OpenSBI firmware image as the -bios. It also supports
+the recommended RISC-V bootflow: U-Boot SPL (M-mode) loads OpenSBI fw_dynamic
+firmware and U-Boot proper (S-mode), using the standard -bios functionality.
+
+Running Linux kernel
+--------------------
+
+Linux mainline v5.12 release is tested at the time of writing. To build a
+Linux mainline kernel that can be booted by the ``virt`` machine in
+64-bit mode, simply configure the kernel using the defconfig configuration:
+
+.. code-block:: bash
+
+  $ export ARCH=riscv
+  $ export CROSS_COMPILE=riscv64-linux-
+  $ make defconfig
+  $ make
+
+To boot the newly built Linux kernel in QEMU with the ``virt`` machine:
+
+.. code-block:: bash
+
+  $ qemu-system-riscv64 -M virt -smp 4 -m 2G \
+      -display none -serial stdio \
+      -kernel arch/riscv/boot/Image \
+      -initrd /path/to/rootfs.cpio \
+      -append "root=/dev/ram"
+
+To build a Linux mainline kernel that can be booted by the ``virt`` machine
+in 32-bit mode, use the rv32_defconfig configuration. A patch is required to
+fix the 32-bit boot issue for Linux kernel v5.12.
+
+.. code-block:: bash
+
+  $ export ARCH=riscv
+  $ export CROSS_COMPILE=riscv64-linux-
+  $ curl https://patchwork.kernel.org/project/linux-riscv/patch/20210627135117.28641-1-bmeng.cn@gmail.com/mbox/ > riscv.patch
+  $ git am riscv.patch
+  $ make rv32_defconfig
+  $ make
+
+Replace ``qemu-system-riscv64`` with ``qemu-system-riscv32`` in the command
+line above to boot the 32-bit Linux kernel. A rootfs image containing 32-bit
+applications shall be used in order for kernel to boot to user space.
+
+Running U-Boot
+--------------
+
+U-Boot mainline v2021.04 release is tested at the time of writing. To build an
+S-mode U-Boot bootloader that can be booted by the ``virt`` machine, use
+the qemu-riscv64_smode_defconfig with similar commands as described above for Linux:
+
+.. code-block:: bash
+
+  $ export CROSS_COMPILE=riscv64-linux-
+  $ make qemu-riscv64_smode_defconfig
+
+Boot the 64-bit U-Boot S-mode image directly:
+
+.. code-block:: bash
+
+  $ qemu-system-riscv64 -M virt -smp 4 -m 2G \
+      -display none -serial stdio \
+      -kernel /path/to/u-boot.bin
+
+To test booting U-Boot SPL which in M-mode, which in turn loads a FIT image
+that bundles OpenSBI fw_dynamic firmware and U-Boot proper (S-mode) together,
+build the U-Boot images using riscv64_spl_defconfig:
+
+.. code-block:: bash
+
+  $ export CROSS_COMPILE=riscv64-linux-
+  $ export OPENSBI=/path/to/opensbi-riscv64-generic-fw_dynamic.bin
+  $ make qemu-riscv64_spl_defconfig
+
+The minimal QEMU commands to run U-Boot SPL are:
+
+.. code-block:: bash
+
+  $ qemu-system-riscv64 -M virt -smp 4 -m 2G \
+      -display none -serial stdio \
+      -bios /path/to/u-boot-spl \
+      -device loader,file=/path/to/u-boot.itb,addr=0x80200000
+
+To test 32-bit U-Boot images, switch to use qemu-riscv32_smode_defconfig and
+riscv32_spl_defconfig builds, and replace ``qemu-system-riscv64`` with
+``qemu-system-riscv32`` in the command lines above to boot the 32-bit U-Boot.

docs/system/target-riscv.rst

@@ -69,6 +69,7 @@ undocumented; you can get a complete list by running
    riscv/microchip-icicle-kit
    riscv/shakti-c
    riscv/sifive_u
+   riscv/virt
 
 RISC-V CPU firmware
 -------------------

hw/char/ibex_uart.c

@@ -42,7 +42,8 @@ REG32(INTR_STATE, 0x00)
     FIELD(INTR_STATE, RX_OVERFLOW, 3, 1)
 REG32(INTR_ENABLE, 0x04)
 REG32(INTR_TEST, 0x08)
-REG32(CTRL, 0x0C)
+REG32(ALERT_TEST, 0x0C)
+REG32(CTRL, 0x10)
     FIELD(CTRL, TX_ENABLE, 0, 1)
     FIELD(CTRL, RX_ENABLE, 1, 1)
     FIELD(CTRL, NF, 2, 1)
@@ -52,25 +53,25 @@ REG32(CTRL, 0x0C)
     FIELD(CTRL, PARITY_ODD, 7, 1)
     FIELD(CTRL, RXBLVL, 8, 2)
     FIELD(CTRL, NCO, 16, 16)
-REG32(STATUS, 0x10)
+REG32(STATUS, 0x14)
     FIELD(STATUS, TXFULL, 0, 1)
     FIELD(STATUS, RXFULL, 1, 1)
     FIELD(STATUS, TXEMPTY, 2, 1)
     FIELD(STATUS, RXIDLE, 4, 1)
     FIELD(STATUS, RXEMPTY, 5, 1)
-REG32(RDATA, 0x14)
-REG32(WDATA, 0x18)
-REG32(FIFO_CTRL, 0x1c)
+REG32(RDATA, 0x18)
+REG32(WDATA, 0x1C)
+REG32(FIFO_CTRL, 0x20)
     FIELD(FIFO_CTRL, RXRST, 0, 1)
     FIELD(FIFO_CTRL, TXRST, 1, 1)
     FIELD(FIFO_CTRL, RXILVL, 2, 3)
     FIELD(FIFO_CTRL, TXILVL, 5, 2)
-REG32(FIFO_STATUS, 0x20)
+REG32(FIFO_STATUS, 0x24)
     FIELD(FIFO_STATUS, TXLVL, 0, 5)
     FIELD(FIFO_STATUS, RXLVL, 16, 5)
-REG32(OVRD, 0x24)
-REG32(VAL, 0x28)
-REG32(TIMEOUT_CTRL, 0x2c)
+REG32(OVRD, 0x28)
+REG32(VAL, 0x2C)
+REG32(TIMEOUT_CTRL, 0x30)
 
 static void ibex_uart_update_irqs(IbexUartState *s)
 {

hw/riscv/boot.c

@@ -182,7 +182,7 @@ uint32_t riscv_load_fdt(hwaddr dram_base, uint64_t mem_size, void *fdt)
 {
     uint32_t temp, fdt_addr;
     hwaddr dram_end = dram_base + mem_size;
-    int fdtsize = fdt_totalsize(fdt);
+    int ret, fdtsize = fdt_totalsize(fdt);
 
     if (fdtsize <= 0) {
         error_report("invalid device-tree");
@@ -198,7 +198,9 @@ uint32_t riscv_load_fdt(hwaddr dram_base, uint64_t mem_size, void *fdt)
     temp = MIN(dram_end, 3072 * MiB);
     fdt_addr = QEMU_ALIGN_DOWN(temp - fdtsize, 16 * MiB);
 
-    fdt_pack(fdt);
+    ret = fdt_pack(fdt);
+    /* Should only fail if we've built a corrupted tree */
+    g_assert(ret == 0);
     /* copy in the device tree */
     qemu_fdt_dumpdtb(fdt, fdtsize);
 

hw/riscv/opentitan.c

@@ -58,6 +58,8 @@ static const MemMapEntry ibex_memmap[] = {
     [IBEX_DEV_ALERT_HANDLER] =  {  0x411b0000,  0x1000  },
     [IBEX_DEV_NMI_GEN] =        {  0x411c0000,  0x1000  },
     [IBEX_DEV_OTBN] =           {  0x411d0000,  0x10000 },
+    [IBEX_DEV_PERI] =           {  0x411f0000,  0x10000 },
+    [IBEX_DEV_FLASH_VIRTUAL] =  {  0x80000000,  0x80000 },
 };
 
 static void opentitan_board_init(MachineState *machine)
@@ -133,8 +135,13 @@ static void lowrisc_ibex_soc_realize(DeviceState *dev_soc, Error **errp)
     /* Flash memory */
     memory_region_init_rom(&s->flash_mem, OBJECT(dev_soc), "riscv.lowrisc.ibex.flash",
                            memmap[IBEX_DEV_FLASH].size, &error_fatal);
+    memory_region_init_alias(&s->flash_alias, OBJECT(dev_soc),
+                             "riscv.lowrisc.ibex.flash_virtual", &s->flash_mem, 0,
+                             memmap[IBEX_DEV_FLASH_VIRTUAL].size);
     memory_region_add_subregion(sys_mem, memmap[IBEX_DEV_FLASH].base,
                                 &s->flash_mem);
+    memory_region_add_subregion(sys_mem, memmap[IBEX_DEV_FLASH_VIRTUAL].base,
+                                &s->flash_alias);
 
     /* PLIC */
     if (!sysbus_realize(SYS_BUS_DEVICE(&s->plic), errp)) {
@@ -217,6 +224,8 @@ static void lowrisc_ibex_soc_realize(DeviceState *dev_soc, Error **errp)
         memmap[IBEX_DEV_NMI_GEN].base, memmap[IBEX_DEV_NMI_GEN].size);
     create_unimplemented_device("riscv.lowrisc.ibex.otbn",
         memmap[IBEX_DEV_OTBN].base, memmap[IBEX_DEV_OTBN].size);
+    create_unimplemented_device("riscv.lowrisc.ibex.peri",
+        memmap[IBEX_DEV_PERI].base, memmap[IBEX_DEV_PERI].size);
 }
 
 static void lowrisc_ibex_soc_class_init(ObjectClass *oc, void *data)

hw/riscv/sifive_u.c

@@ -62,6 +62,9 @@
 
 #include <libfdt.h>
 
+/* CLINT timebase frequency */
+#define CLINT_TIMEBASE_FREQ 1000000
+
 static const MemMapEntry sifive_u_memmap[] = {
     [SIFIVE_U_DEV_DEBUG] =    {        0x0,      0x100 },
     [SIFIVE_U_DEV_MROM] =     {     0x1000,     0xf000 },
@@ -165,7 +168,7 @@ static void create_fdt(SiFiveUState *s, const MemMapEntry *memmap,
 
     qemu_fdt_add_subnode(fdt, "/cpus");
     qemu_fdt_setprop_cell(fdt, "/cpus", "timebase-frequency",
-        SIFIVE_CLINT_TIMEBASE_FREQ);
+        CLINT_TIMEBASE_FREQ);
     qemu_fdt_setprop_cell(fdt, "/cpus", "#size-cells", 0x0);
     qemu_fdt_setprop_cell(fdt, "/cpus", "#address-cells", 0x1);
 
@@ -599,17 +602,18 @@ static void sifive_u_machine_init(MachineState *machine)
     }
 
     /* reset vector */
-    uint32_t reset_vec[11] = {
+    uint32_t reset_vec[12] = {
         s->msel,                       /* MSEL pin state */
         0x00000297,                    /* 1:  auipc  t0, %pcrel_hi(fw_dyn) */
-        0x02828613,                    /*     addi   a2, t0, %pcrel_lo(1b) */
+        0x02c28613,                    /*     addi   a2, t0, %pcrel_lo(1b) */
         0xf1402573,                    /*     csrr   a0, mhartid  */
         0,
         0,
         0x00028067,                    /*     jr     t0 */
         start_addr,                    /* start: .dword */
         start_addr_hi32,
         fdt_load_addr,                 /* fdt_laddr: .dword */
+        0x00000000,
         0x00000000,
                                        /* fw_dyn: */
     };
@@ -847,7 +851,7 @@ static void sifive_u_soc_realize(DeviceState *dev, Error **errp)
     sifive_clint_create(memmap[SIFIVE_U_DEV_CLINT].base,
         memmap[SIFIVE_U_DEV_CLINT].size, 0, ms->smp.cpus,
         SIFIVE_SIP_BASE, SIFIVE_TIMECMP_BASE, SIFIVE_TIME_BASE,
-        SIFIVE_CLINT_TIMEBASE_FREQ, false);
+        CLINT_TIMEBASE_FREQ, false);
 
     if (!sysbus_realize(SYS_BUS_DEVICE(&s->prci), errp)) {
         return;

include/hw/riscv/opentitan.h

@@ -40,6 +40,7 @@ struct LowRISCIbexSoCState {
 
     MemoryRegion flash_mem;
     MemoryRegion rom;
+    MemoryRegion flash_alias;
 };
 
 typedef struct OpenTitanState {
@@ -54,6 +55,7 @@ enum {
     IBEX_DEV_ROM,
     IBEX_DEV_RAM,
     IBEX_DEV_FLASH,
+    IBEX_DEV_FLASH_VIRTUAL,
     IBEX_DEV_UART,
     IBEX_DEV_GPIO,
     IBEX_DEV_SPI,
@@ -81,6 +83,7 @@ enum {
     IBEX_DEV_ALERT_HANDLER,
     IBEX_DEV_NMI_GEN,
     IBEX_DEV_OTBN,
+    IBEX_DEV_PERI,
 };
 
 enum {