wireguard-linux/arch/riscv/kernel/head.S, branch jd/unified-crypt-queue

riscv: Add SOC early init support

2020-04-03T17:46:43Z

Add a mechanism for early SoC initialization for platforms that need additional hardware initialization not possible through the regular device tree and drivers mechanism. With this, a SoC specific initialization function can be called very early, before DTB parsing is done by parse_dtb() in Linux RISC-V kernel setup code. This can be very useful for early hardware initialization for No-MMU kernels booted directly in M-mode because it is quite likely that no other booting stage exist prior to the No-MMU kernel. Example use of a SoC early initialization is as follows: static void vendor_abc_early_init(const void *fdt) { /* * some early init code here that can use simple matches * against the flat device tree file. */ } SOC_EARLY_INIT_DECLARE("vendor,abc", abc_early_init); This early initialization function is executed only if the flat device tree for the board has a 'compatible = "vendor,abc"' entry; Signed-off-by: Damien Le Moal Signed-off-by: Anup Patel Signed-off-by: Palmer Dabbelt

RISC-V: Add supported for ordered booting method using HSM

2020-03-31T18:27:50Z

Currently, all harts have to jump Linux in RISC-V. This complicates the multi-stage boot process as every transient stage also has to ensure all harts enter to that stage and jump to Linux afterwards. It also obstructs a clean Kexec implementation. SBI HSM extension provides alternate solutions where only a single hart need to boot and enter Linux. The booting hart can bring up secondary harts one by one afterwards. Add SBI HSM based cpu_ops that implements an ordered booting method in RISC-V. This change is also backward compatible with older firmware not implementing HSM extension. If a latest kernel is used with older firmware, it will continue to use the default spinning booting method. Signed-off-by: Atish Patra Reviewed-by: Anup Patel Signed-off-by: Palmer Dabbelt

RISC-V: Move relocate and few other functions out of __init

2020-03-31T18:25:50Z

The secondary hart booting and relocation code are under .init section. As a result, it will be freed once kernel booting is done. However, ordered booting protocol and CPU hotplug always requires these functions to be present to bringup harts after initial kernel boot. Move the required functions to a different section and make sure that they are in memory within first 2MB offset as trampoline page directory only maps first 2MB. Signed-off-by: Atish Patra Reviewed-by: Anup Patel Signed-off-by: Palmer Dabbelt

riscv: set pmp configuration if kernel is running in M-mode

2020-02-18T17:41:24Z

When the kernel is running in S-mode, the expectation is that the bootloader or SBI layer will configure the PMP to allow the kernel to access physical memory. But, when the kernel is running in M-mode and is started with the ELF "loader", there's probably no bootloader or SBI layer involved to configure the PMP. Thus, we need to configure the PMP ourselves to enable the kernel to access all regions. Signed-off-by: Greentime Hu Reviewed-by: Palmer Dabbelt Signed-off-by: Palmer Dabbelt

riscv: Add KASAN support

2020-01-22T21:09:58Z

This patch ports the feature Kernel Address SANitizer (KASAN). Note: The start address of shadow memory is at the beginning of kernel space, which is 2^64 - (2^39 / 2) in SV39. The size of the kernel space is 2^38 bytes so the size of shadow memory should be 2^38 / 8. Thus, the shadow memory would not overlap with the fixmap area. There are currently two limitations in this port, 1. RV64 only: KASAN need large address space for extra shadow memory region. 2. KASAN can't debug the modules since the modules are allocated in VMALLOC area. We mapped the shadow memory, which corresponding to VMALLOC area, to the kasan_early_shadow_page because we don't have enough physical space for all the shadow memory corresponding to VMALLOC area. Signed-off-by: Nick Hu Reported-by: Greentime Hu Signed-off-by: Palmer Dabbelt

riscv: make sure the cores stay looping in .Lsecondary_park

2020-01-16T02:07:54Z

The code in secondary_park is currently placed in the .init section. The kernel reclaims and clears this code when it finishes booting. That causes the cores parked in it to go to somewhere unpredictable, so we move this function out of init to make sure the cores stay looping there. The instruction bgeu a0, t0, .Lsecondary_park may have "a relocation truncated to fit" issue during linking time. It is because that sections are too far to jump. Let's use tail to jump to the .Lsecondary_park. Signed-off-by: Greentime Hu Reviewed-by: Anup Patel Cc: Andreas Schwab Cc: stable@vger.kernel.org Fixes: 76d2a0493a17d ("RISC-V: Init and Halt Code") Signed-off-by: Paul Walmsley

riscv: Fixup obvious bug for fp-regs reset

2020-01-12T18:12:44Z

CSR_MISA is defined in Privileged Architectures' spec: 3.1.1 Machine ISA Register misa. Every bit:1 indicate a feature, so we should beqz reset_done when there is no F/D bit in csr_misa register. Signed-off-by: Guo Ren [paul.walmsley@sifive.com: fix typo in commit message] Fixes: 9e80635619b51 ("riscv: clear the instruction cache and all registers when booting") Signed-off-by: Paul Walmsley

riscv: fix scratch register clearing in M-mode.

2019-12-20T11:32:24Z

This patch fixes that the sscratch register clearing in M-mode. It cleared sscratch register in M-mode, but it should clear mscratch register. That will cause kernel trap if the CPU core doesn't support S-mode when trying to access sscratch. Fixes: 9e80635619b5 ("riscv: clear the instruction cache and all registers when booting") Signed-off-by: Greentime Hu Reviewed-by: Anup Patel Signed-off-by: Paul Walmsley

riscv: add nommu support

2019-11-17T23:17:39Z

The kernel runs in M-mode without using page tables, and thus can't run bare metal without help from additional firmware. Most of the patch is just stubbing out code not needed without page tables, but there is an interesting detail in the signals implementation: - The normal RISC-V syscall ABI only implements rt_sigreturn as VDSO entry point, but the ELF VDSO is not supported for nommu Linux. We instead copy the code to call the syscall onto the stack. In addition to enabling the nommu code a new defconfig for a small kernel image that can run in nommu mode on qemu is also provided, to run a kernel in qemu you can use the following command line: qemu-system-riscv64 -smp 2 -m 64 -machine virt -nographic \ -kernel arch/riscv/boot/loader \ -drive file=rootfs.ext2,format=raw,id=hd0 \ -device virtio-blk-device,drive=hd0 Contains contributions from Damien Le Moal . Signed-off-by: Christoph Hellwig Reviewed-by: Anup Patel [paul.walmsley@sifive.com: updated to apply; add CONFIG_MMU guards around PCI_IOBASE definition to fix build issues; fixed checkpatch issues; move the PCI_IO_* and VMEMMAP address space macros along with the others; resolve sparse warning] Signed-off-by: Paul Walmsley

riscv: clear the instruction cache and all registers when booting

2019-11-17T23:17:39Z

When we get booted we want a clear slate without any leaks from previous supervisors or the firmware. Flush the instruction cache and then clear all registers to known good values. This is really important for the upcoming nommu support that runs on M-mode, but can't really harm when running in S-mode either. Vaguely based on the concepts from opensbi. Signed-off-by: Christoph Hellwig Reviewed-by: Anup Patel Signed-off-by: Paul Walmsley