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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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6bd33e1ece
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 <Damien.LeMoal@wdc.com>. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Anup Patel <anup@brainfault.org> [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 <paul.walmsley@sifive.com>
23 lines
516 B
C
23 lines
516 B
C
/* SPDX-License-Identifier: GPL-2.0-only */
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/*
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* Copyright (C) 2017 Chen Liqin <liqin.chen@sunplusct.com>
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* Copyright (C) 2012 Regents of the University of California
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*/
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#ifndef _ASM_RISCV_CACHE_H
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#define _ASM_RISCV_CACHE_H
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#define L1_CACHE_SHIFT 6
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#define L1_CACHE_BYTES (1 << L1_CACHE_SHIFT)
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/*
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* RISC-V requires the stack pointer to be 16-byte aligned, so ensure that
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* the flat loader aligns it accordingly.
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*/
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#ifndef CONFIG_MMU
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#define ARCH_SLAB_MINALIGN 16
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#endif
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#endif /* _ASM_RISCV_CACHE_H */
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