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95 lines
2.8 KiB
95 lines
2.8 KiB
/* SPDX-License-Identifier: GPL-2.0-only */ |
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/* |
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* Hibernate low-level support |
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* |
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* Copyright (C) 2016 ARM Ltd. |
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* Author: James Morse <james.morse@arm.com> |
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*/ |
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#include <linux/linkage.h> |
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#include <linux/errno.h> |
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#include <asm/asm-offsets.h> |
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#include <asm/assembler.h> |
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#include <asm/cputype.h> |
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#include <asm/memory.h> |
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#include <asm/page.h> |
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#include <asm/virt.h> |
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/* |
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* Resume from hibernate |
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* |
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* Loads temporary page tables then restores the memory image. |
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* Finally branches to cpu_resume() to restore the state saved by |
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* swsusp_arch_suspend(). |
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* |
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* Because this code has to be copied to a 'safe' page, it can't call out to |
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* other functions by PC-relative address. Also remember that it may be |
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* mid-way through over-writing other functions. For this reason it contains |
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* code from caches_clean_inval_pou() and uses the copy_page() macro. |
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* |
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* This 'safe' page is mapped via ttbr0, and executed from there. This function |
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* switches to a copy of the linear map in ttbr1, performs the restore, then |
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* switches ttbr1 to the original kernel's swapper_pg_dir. |
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* |
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* All of memory gets written to, including code. We need to clean the kernel |
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* text to the Point of Coherence (PoC) before secondary cores can be booted. |
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* Because the kernel modules and executable pages mapped to user space are |
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* also written as data, we clean all pages we touch to the Point of |
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* Unification (PoU). |
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* |
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* x0: physical address of temporary page tables |
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* x1: physical address of swapper page tables |
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* x2: address of cpu_resume |
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* x3: linear map address of restore_pblist in the current kernel |
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* x4: physical address of __hyp_stub_vectors, or 0 |
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* x5: physical address of a zero page that remains zero after resume |
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*/ |
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.pushsection ".hibernate_exit.text", "ax" |
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SYM_CODE_START(swsusp_arch_suspend_exit) |
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/* |
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* We execute from ttbr0, change ttbr1 to our copied linear map tables |
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* with a break-before-make via the zero page |
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*/ |
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break_before_make_ttbr_switch x5, x0, x6, x8 |
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mov x21, x1 |
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mov x30, x2 |
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mov x24, x4 |
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mov x25, x5 |
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/* walk the restore_pblist and use copy_page() to over-write memory */ |
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mov x19, x3 |
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1: ldr x10, [x19, #HIBERN_PBE_ORIG] |
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mov x0, x10 |
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ldr x1, [x19, #HIBERN_PBE_ADDR] |
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copy_page x0, x1, x2, x3, x4, x5, x6, x7, x8, x9 |
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add x1, x10, #PAGE_SIZE |
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/* Clean the copied page to PoU - based on caches_clean_inval_pou() */ |
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raw_dcache_line_size x2, x3 |
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sub x3, x2, #1 |
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bic x4, x10, x3 |
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2: /* clean D line / unified line */ |
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alternative_insn "dc cvau, x4", "dc civac, x4", ARM64_WORKAROUND_CLEAN_CACHE |
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add x4, x4, x2 |
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cmp x4, x1 |
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b.lo 2b |
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ldr x19, [x19, #HIBERN_PBE_NEXT] |
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cbnz x19, 1b |
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dsb ish /* wait for PoU cleaning to finish */ |
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/* switch to the restored kernels page tables */ |
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break_before_make_ttbr_switch x25, x21, x6, x8 |
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ic ialluis |
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dsb ish |
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isb |
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cbz x24, 3f /* Do we need to re-initialise EL2? */ |
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hvc #0 |
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3: ret |
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SYM_CODE_END(swsusp_arch_suspend_exit) |
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.popsection
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