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3060e9f0d1
The ARM architecture defines the memory locations that are permitted
to be accessed as the result of a speculative instruction fetch from
an exception level for which all stages of translation are disabled.
Specifically, the core is permitted to speculatively fetch from the
4KB region containing the current program counter 4K and next 4K.
When translation is changed from enabled to disabled for the running
exception level (SCTLR_ELn[M] changed from a value of 1 to 0), the
Falkor core may errantly speculatively access memory locations outside
of the 4KB region permitted by the architecture. The errant memory
access may lead to one of the following unexpected behaviors.
1) A System Error Interrupt (SEI) being raised by the Falkor core due
to the errant memory access attempting to access a region of memory
that is protected by a slave-side memory protection unit.
2) Unpredictable device behavior due to a speculative read from device
memory. This behavior may only occur if the instruction cache is
disabled prior to or coincident with translation being changed from
enabled to disabled.
The conditions leading to this erratum will not occur when either of the
following occur:
1) A higher exception level disables translation of a lower exception level
(e.g. EL2 changing SCTLR_EL1[M] from a value of 1 to 0).
2) An exception level disabling its stage-1 translation if its stage-2
translation is enabled (e.g. EL1 changing SCTLR_EL1[M] from a value of 1
to 0 when HCR_EL2[VM] has a value of 1).
To avoid the errant behavior, software must execute an ISB immediately
prior to executing the MSR that will change SCTLR_ELn[M] from 1 to 0.
Signed-off-by: Shanker Donthineni <shankerd@codeaurora.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
132 lines
2.9 KiB
ArmAsm
132 lines
2.9 KiB
ArmAsm
/*
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* kexec for arm64
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*
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* Copyright (C) Linaro.
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* Copyright (C) Huawei Futurewei Technologies.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/kexec.h>
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#include <linux/linkage.h>
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#include <asm/assembler.h>
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#include <asm/kexec.h>
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#include <asm/page.h>
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#include <asm/sysreg.h>
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/*
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* arm64_relocate_new_kernel - Put a 2nd stage image in place and boot it.
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*
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* The memory that the old kernel occupies may be overwritten when coping the
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* new image to its final location. To assure that the
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* arm64_relocate_new_kernel routine which does that copy is not overwritten,
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* all code and data needed by arm64_relocate_new_kernel must be between the
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* symbols arm64_relocate_new_kernel and arm64_relocate_new_kernel_end. The
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* machine_kexec() routine will copy arm64_relocate_new_kernel to the kexec
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* control_code_page, a special page which has been set up to be preserved
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* during the copy operation.
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*/
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ENTRY(arm64_relocate_new_kernel)
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/* Setup the list loop variables. */
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mov x17, x1 /* x17 = kimage_start */
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mov x16, x0 /* x16 = kimage_head */
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raw_dcache_line_size x15, x0 /* x15 = dcache line size */
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mov x14, xzr /* x14 = entry ptr */
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mov x13, xzr /* x13 = copy dest */
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/* Clear the sctlr_el2 flags. */
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mrs x0, CurrentEL
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cmp x0, #CurrentEL_EL2
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b.ne 1f
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mrs x0, sctlr_el2
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ldr x1, =SCTLR_ELx_FLAGS
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bic x0, x0, x1
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pre_disable_mmu_workaround
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msr sctlr_el2, x0
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isb
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1:
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/* Check if the new image needs relocation. */
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tbnz x16, IND_DONE_BIT, .Ldone
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.Lloop:
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and x12, x16, PAGE_MASK /* x12 = addr */
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/* Test the entry flags. */
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.Ltest_source:
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tbz x16, IND_SOURCE_BIT, .Ltest_indirection
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/* Invalidate dest page to PoC. */
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mov x0, x13
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add x20, x0, #PAGE_SIZE
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sub x1, x15, #1
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bic x0, x0, x1
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2: dc ivac, x0
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add x0, x0, x15
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cmp x0, x20
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b.lo 2b
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dsb sy
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mov x20, x13
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mov x21, x12
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copy_page x20, x21, x0, x1, x2, x3, x4, x5, x6, x7
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/* dest += PAGE_SIZE */
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add x13, x13, PAGE_SIZE
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b .Lnext
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.Ltest_indirection:
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tbz x16, IND_INDIRECTION_BIT, .Ltest_destination
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/* ptr = addr */
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mov x14, x12
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b .Lnext
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.Ltest_destination:
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tbz x16, IND_DESTINATION_BIT, .Lnext
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/* dest = addr */
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mov x13, x12
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.Lnext:
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/* entry = *ptr++ */
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ldr x16, [x14], #8
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/* while (!(entry & DONE)) */
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tbz x16, IND_DONE_BIT, .Lloop
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.Ldone:
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/* wait for writes from copy_page to finish */
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dsb nsh
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ic iallu
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dsb nsh
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isb
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/* Start new image. */
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mov x0, xzr
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mov x1, xzr
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mov x2, xzr
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mov x3, xzr
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br x17
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ENDPROC(arm64_relocate_new_kernel)
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.ltorg
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.align 3 /* To keep the 64-bit values below naturally aligned. */
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.Lcopy_end:
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.org KEXEC_CONTROL_PAGE_SIZE
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/*
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* arm64_relocate_new_kernel_size - Number of bytes to copy to the
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* control_code_page.
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*/
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.globl arm64_relocate_new_kernel_size
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arm64_relocate_new_kernel_size:
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.quad .Lcopy_end - arm64_relocate_new_kernel
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