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![Masahiro Yamada](/assets/img/avatar_default.png)
There are two enable methods supported by ARM64 Linux; psci and spin-table. The latter is simpler and helpful for quick SoC bring up. My main motivation for this patch is to improve the spin-table support, which allows us to boot an ARMv8 system without the ARM Trusted Firmware. Currently, we have multi-entry code in arch/arm/cpu/armv8/start.S and the spin-table is supported in a really ad-hoc way, and I see some problems: - We must hard-code CPU_RELEASE_ADDR so that it matches the "cpu-release-addr" property in the DT that comes from the kernel tree. - The Documentation/arm64/booting.txt in Linux requires that the release address must be zero-initialized, but it is not cared by the common code in U-Boot. We must do it in a board function. - There is no systematic way to protect the spin-table code from the kernel. We are supposed to do it in a board specific manner, but it is difficult to predict where the spin-table code will be located after the relocation. So, it also makes difficult to hard-code /memreserve/ in the DT of the kernel. So, here is a patch to solve those problems; the DT is run-time modified to reserve the spin-table code (+ cpu-release-addr). Also, the "cpu-release-addr" property is set to an appropriate address after the relocation, which means we no longer need the hard-coded CPU_RELEASE_ADDR. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
15 lines
291 B
C
15 lines
291 B
C
/*
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* SPDX-License-Identifier: GPL-2.0+
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*/
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#ifndef __ASM_SPIN_TABLE_H__
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#define __ASM_SPIN_TABLE_H__
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extern u64 spin_table_cpu_release_addr;
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extern char spin_table_reserve_begin;
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extern char spin_table_reserve_end;
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int spin_table_update_dt(void *fdt);
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#endif /* __ASM_SPIN_TABLE_H__ */
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