Merge remote-tracking branch 'remotes/alistair/tags/pull-riscv-to-apply-20210608-1' into staging

Second RISC-V PR for QEMU 6.1

 - Update the PLIC and CLINT DT bindings
 - Improve documentation for RISC-V machines
 - Support direct kernel boot for microchip_pfsoc
 - Fix WFI exception behaviour
 - Improve CSR printing
 - Initial support for the experimental Bit Manip extension

# gpg: Signature made Tue 08 Jun 2021 01:28:27 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-20210608-1: (32 commits)
  target/riscv: rvb: add b-ext version cpu option
  target/riscv: rvb: support and turn on B-extension from command line
  target/riscv: rvb: add/shift with prefix zero-extend
  target/riscv: rvb: address calculation
  target/riscv: rvb: generalized or-combine
  target/riscv: rvb: generalized reverse
  target/riscv: rvb: rotate (left/right)
  target/riscv: rvb: shift ones
  target/riscv: rvb: single-bit instructions
  target/riscv: add gen_shifti() and gen_shiftiw() helper functions
  target/riscv: rvb: sign-extend instructions
  target/riscv: rvb: min/max instructions
  target/riscv: rvb: pack two words into one register
  target/riscv: rvb: logic-with-negate
  target/riscv: rvb: count bits set
  target/riscv: rvb: count leading/trailing zeros
  target/riscv: reformat @sh format encoding for B-extension
  target/riscv: Pass the same value to oprsz and maxsz.
  target/riscv/pmp: Add assert for ePMP operations
  target/riscv: Dump CSR mscratch/sscratch/satp
  ...

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

5 files changed, 108 insertions, 56 deletions

diff --git a/docs/system/deprecated.rst b/docs/system/deprecated.rst
index abbf8243a3..e2e0090878 100644
--- a/docs/system/deprecated.rst
+++ b/docs/system/deprecated.rst
@@ -52,25 +52,6 @@ pcspk-audiodev=<name>``.
 ``tty`` and ``parport`` are aliases that will be removed. Instead, the
 actual backend names ``serial`` and ``parallel`` should be used.
 
-RISC-V ``-bios`` (since 5.1)
-''''''''''''''''''''''''''''
-
-QEMU 4.1 introduced support for the -bios option in QEMU for RISC-V for the
-RISC-V virt machine and sifive_u machine. QEMU 4.1 had no changes to the
-default behaviour to avoid breakages.
-
-QEMU 5.1 changes the default behaviour from ``-bios none`` to ``-bios default``.
-
-QEMU 5.1 has three options:
- 1. ``-bios default`` - This is the current default behavior if no -bios option
-      is included. This option will load the default OpenSBI firmware automatically.
-      The firmware is included with the QEMU release and no user interaction is
-      required. All a user needs to do is specify the kernel they want to boot
-      with the -kernel option
- 2. ``-bios none`` - QEMU will not automatically load any firmware. It is up
-      to the user to load all the images they need.
- 3. ``-bios <file>`` - Tells QEMU to load the specified file as the firmwrae.
-
 Short-form boolean options (since 6.0)
 ''''''''''''''''''''''''''''''''''''''
 
diff --git a/docs/system/removed-features.rst b/docs/system/removed-features.rst
index 1d22195b1d..2b21bd39ab 100644
--- a/docs/system/removed-features.rst
+++ b/docs/system/removed-features.rst
@@ -126,6 +126,11 @@ devices.  Drives the board doesn't pick up can no longer be used with
 This option was undocumented and not used in the field.
 Use `-device usb-ccid`` instead.
 
+RISC-V firmware not booted by default (removed in 5.1)
+''''''''''''''''''''''''''''''''''''''''''''''''''''''
+
+QEMU 5.1 changes the default behaviour from ``-bios none`` to ``-bios default``
+for the RISC-V ``virt`` machine and ``sifive_u`` machine.
 
 QEMU Machine Protocol (QMP) commands
 ------------------------------------
diff --git a/docs/system/riscv/microchip-icicle-kit.rst b/docs/system/riscv/microchip-icicle-kit.rst
index 4fe97bce3f..54ced661e3 100644
--- a/docs/system/riscv/microchip-icicle-kit.rst
+++ b/docs/system/riscv/microchip-icicle-kit.rst
@@ -15,33 +15,53 @@ Supported devices
 
 The ``microchip-icicle-kit`` machine supports the following devices:
 
- * 1 E51 core
- * 4 U54 cores
- * Core Level Interruptor (CLINT)
- * Platform-Level Interrupt Controller (PLIC)
- * L2 Loosely Integrated Memory (L2-LIM)
- * DDR memory controller
- * 5 MMUARTs
- * 1 DMA controller
- * 2 GEM Ethernet controllers
- * 1 SDHC storage controller
+* 1 E51 core
+* 4 U54 cores
+* Core Level Interruptor (CLINT)
+* Platform-Level Interrupt Controller (PLIC)
+* L2 Loosely Integrated Memory (L2-LIM)
+* DDR memory controller
+* 5 MMUARTs
+* 1 DMA controller
+* 2 GEM Ethernet controllers
+* 1 SDHC storage controller
 
 Boot options
 ------------
 
 The ``microchip-icicle-kit`` machine can start using the standard -bios
 functionality for loading its BIOS image, aka Hart Software Services (HSS_).
-HSS loads the second stage bootloader U-Boot from an SD card. It does not
-support direct kernel loading via the -kernel option. One has to load kernel
-from U-Boot.
+HSS loads the second stage bootloader U-Boot from an SD card. Then a kernel
+can be loaded from U-Boot. It also supports direct kernel booting via the
+-kernel option along with the device tree blob via -dtb. When direct kernel
+boot is used, the OpenSBI fw_dynamic BIOS image is used to boot a payload
+like U-Boot or OS kernel directly.
+
+The user provided DTB should have the following requirements:
+
+* The /cpus node should contain at least one subnode for E51 and the number
+  of subnodes 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"
+
+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
+=====  ========== =======
 
 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
 init routine to prompt user to increase the RAM size to > 1537 MiB when less
 than 1537 MiB ram is detected.
 
-Boot the machine
-----------------
+Running HSS
+-----------
 
 HSS 2020.12 release is tested at the time of writing. To build an HSS image
 that can be booted by the ``microchip-icicle-kit`` machine, type the following
diff --git a/docs/system/riscv/sifive_u.rst b/docs/system/riscv/sifive_u.rst
index 98e7562848..32d0a1b85d 100644
--- a/docs/system/riscv/sifive_u.rst
+++ b/docs/system/riscv/sifive_u.rst
@@ -9,21 +9,21 @@ Supported devices
 
 The ``sifive_u`` machine supports the following devices:
 
- * 1 E51 / E31 core
- * Up to 4 U54 / U34 cores
- * Core Level Interruptor (CLINT)
- * Platform-Level Interrupt Controller (PLIC)
- * Power, Reset, Clock, Interrupt (PRCI)
- * L2 Loosely Integrated Memory (L2-LIM)
- * DDR memory controller
- * 2 UARTs
- * 1 GEM Ethernet controller
- * 1 GPIO controller
- * 1 One-Time Programmable (OTP) memory with stored serial number
- * 1 DMA controller
- * 2 QSPI controllers
- * 1 ISSI 25WP256 flash
- * 1 SD card in SPI mode
+* 1 E51 / E31 core
+* Up to 4 U54 / U34 cores
+* Core Level Interruptor (CLINT)
+* Platform-Level Interrupt Controller (PLIC)
+* Power, Reset, Clock, Interrupt (PRCI)
+* L2 Loosely Integrated Memory (L2-LIM)
+* DDR memory controller
+* 2 UARTs
+* 1 GEM Ethernet controller
+* 1 GPIO controller
+* 1 One-Time Programmable (OTP) memory with stored serial number
+* 1 DMA controller
+* 2 QSPI controllers
+* 1 ISSI 25WP256 flash
+* 1 SD card in SPI mode
 
 Please note the real world HiFive Unleashed board has a fixed configuration of
 1 E51 core and 4 U54 core combination and the RISC-V core boots in 64-bit mode.
@@ -36,12 +36,21 @@ Hardware configuration information
 ----------------------------------
 
 The ``sifive_u`` machine automatically generates a device tree blob ("dtb")
-which it passes to the guest. 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 instead of using a DTB for the real hardware, as some of the devices are
-not modeled by QEMU and trying to access these devices may cause unexpected
-behavior.
+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 instead of using a DTB for the real
+hardware, as some of the devices are not modeled by QEMU and trying to access
+these devices may cause unexpected behavior.
+
+If users want to provide their own DTB, they can use the ``-dtb`` option.
+These DTBs should have the following requirements:
+
+* The /cpus node should contain at least one subnode for E51 and the number
+  of subnodes 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
 ------------
@@ -122,6 +131,32 @@ To boot the newly built Linux kernel in QEMU with the ``sifive_u`` machine:
       -initrd /path/to/rootfs.ext4 \
       -append "root=/dev/ram"
 
+Alternatively, we can use a custom DTB to boot the machine by inserting a CLINT
+node in fu540-c000.dtsi in the Linux kernel,
+
+.. code-block:: none
+
+    clint: clint@2000000 {
+        compatible = "riscv,clint0";
+        interrupts-extended = <&cpu0_intc 3 &cpu0_intc 7
+                               &cpu1_intc 3 &cpu1_intc 7
+                               &cpu2_intc 3 &cpu2_intc 7
+                               &cpu3_intc 3 &cpu3_intc 7
+                               &cpu4_intc 3 &cpu4_intc 7>;
+        reg = <0x00 0x2000000 0x00 0x10000>;
+    };
+
+with the following command line options:
+
+.. code-block:: bash
+
+  $ qemu-system-riscv64 -M sifive_u -smp 5 -m 8G \
+      -display none -serial stdio \
+      -kernel arch/riscv/boot/Image \
+      -dtb arch/riscv/boot/dts/sifive/hifive-unleashed-a00.dtb \
+      -initrd /path/to/rootfs.ext4 \
+      -append "root=/dev/ram"
+
 To build a Linux mainline kernel that can be booted by the ``sifive_u`` machine
 in 32-bit mode, use the rv32_defconfig configuration. A patch is required to
 fix the 32-bit boot issue for Linux kernel v5.10.
diff --git a/docs/system/target-riscv.rst b/docs/system/target-riscv.rst
index 4b3c78382c..a5cc06b726 100644
--- a/docs/system/target-riscv.rst
+++ b/docs/system/target-riscv.rst
@@ -70,5 +70,16 @@ undocumented; you can get a complete list by running
    riscv/shakti-c
    riscv/sifive_u
 
-RISC-V CPU features
+RISC-V CPU firmware
 -------------------
+
+When using the ``sifive_u`` or ``virt`` machine there are three different
+firmware boot options:
+1. ``-bios default`` - This is the default behaviour if no -bios option
+is included. This option will load the default OpenSBI firmware automatically.
+The firmware is included with the QEMU release and no user interaction is
+required. All a user needs to do is specify the kernel they want to boot
+with the -kernel option
+2. ``-bios none`` - QEMU will not automatically load any firmware. It is up
+to the user to load all the images they need.
+3. ``-bios <file>`` - Tells QEMU to load the specified file as the firmware.