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arm64: acpi: fix alignment fault in accessing ACPI

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This is a fix against the issue that crash dump kernel may hang up
during booting, which can happen on any ACPI-based system with "ACPI
Reclaim Memory."

(kernel messages after panic kicked off kdump)
	   (snip...)
	Bye!
	   (snip...)
	ACPI: Core revision 20170728
	pud=000000002e7d0003, *pmd=000000002e7c0003, *pte=00e8000039710707
	Internal error: Oops: 96000021 [#1] SMP
	Modules linked in:
	CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.14.0-rc6 #1
	task: ffff000008d05180 task.stack: ffff000008cc0000
	PC is at acpi_ns_lookup+0x25c/0x3c0
	LR is at acpi_ds_load1_begin_op+0xa4/0x294
	   (snip...)
	Process swapper/0 (pid: 0, stack limit = 0xffff000008cc0000)
	Call trace:
	   (snip...)
	[<ffff0000084a6764>] acpi_ns_lookup+0x25c/0x3c0
	[<ffff00000849b4f8>] acpi_ds_load1_begin_op+0xa4/0x294
	[<ffff0000084ad4ac>] acpi_ps_build_named_op+0xc4/0x198
	[<ffff0000084ad6cc>] acpi_ps_create_op+0x14c/0x270
	[<ffff0000084acfa8>] acpi_ps_parse_loop+0x188/0x5c8
	[<ffff0000084ae048>] acpi_ps_parse_aml+0xb0/0x2b8
	[<ffff0000084a8e10>] acpi_ns_one_complete_parse+0x144/0x184
	[<ffff0000084a8e98>] acpi_ns_parse_table+0x48/0x68
	[<ffff0000084a82cc>] acpi_ns_load_table+0x4c/0xdc
	[<ffff0000084b32f8>] acpi_tb_load_namespace+0xe4/0x264
	[<ffff000008baf9b4>] acpi_load_tables+0x48/0xc0
	[<ffff000008badc20>] acpi_early_init+0x9c/0xd0
	[<ffff000008b70d50>] start_kernel+0x3b4/0x43c
	Code: b9008fb9 2a000318 36380054 32190318 (b94002c0)
	---[ end trace c46ed37f9651c58e ]---
	Kernel panic - not syncing: Fatal exception
	Rebooting in 10 seconds..

(diagnosis)
* This fault is a data abort, alignment fault (ESR=0x96000021)
  during reading out ACPI table.
* Initial ACPI tables are normally stored in system ram and marked as
  "ACPI Reclaim memory" by the firmware.
* After the commit f56ab9a5b73c ("efi/arm: Don't mark ACPI reclaim
  memory as MEMBLOCK_NOMAP"), those regions are differently handled
  as they are "memblock-reserved", without NOMAP bit.
* So they are now excluded from device tree's "usable-memory-range"
  which kexec-tools determines based on a current view of /proc/iomem.
* When crash dump kernel boots up, it tries to accesses ACPI tables by
  mapping them with ioremap(), not ioremap_cache(), in acpi_os_ioremap()
  since they are no longer part of mapped system ram.
* Given that ACPI accessor/helper functions are compiled in without
  unaligned access support (ACPI_MISALIGNMENT_NOT_SUPPORTED),
  any unaligned access to ACPI tables can cause a fatal panic.

With this patch, acpi_os_ioremap() always honors memory attribute
information provided by the firmware (EFI) and retaining cacheability
allows the kernel safe access to ACPI tables.

Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
Reviewed-by: James Morse <james.morse@arm.com>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reported-by and Tested-by: Bhupesh Sharma <bhsharma@redhat.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
This commit is contained in:
AKASHI Takahiro 2018-07-23 10:57:32 +09:00 committed by Will Deacon
parent 20d12cf990
commit 09ffcb0d71
2 changed files with 20 additions and 16 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

25
arch/arm64/include/asm/acpi.h
View File

@ -12,10 +12,12 @@
#ifndef _ASM_ACPI_H
#define _ASM_ACPI_H
#include <linux/efi.h>
#include <linux/memblock.h>
#include <linux/psci.h>
#include <asm/cputype.h>
#include <asm/io.h>
#include <asm/smp_plat.h>
#include <asm/tlbflush.h>
@ -29,18 +31,22 @@
/* Basic configuration for ACPI */
#ifdef CONFIG_ACPI
pgprot_t __acpi_get_mem_attribute(phys_addr_t addr);
/* ACPI table mapping after acpi_permanent_mmap is set */
static inline void __iomem *acpi_os_ioremap(acpi_physical_address phys,
acpi_size size)
{
/*
* EFI's reserve_regions() call adds memory with the WB attribute
* to memblock via early_init_dt_add_memory_arch().
*/
if (!memblock_is_memory(phys))
return ioremap(phys, size);
/* For normal memory we already have a cacheable mapping. */
if (memblock_is_map_memory(phys))
return (void __iomem *)__phys_to_virt(phys);
return ioremap_cache(phys, size);
/*
* We should still honor the memory's attribute here because
* crash dump kernel possibly excludes some ACPI (reclaim)
* regions from memblock list.
*/
return __ioremap(phys, size, __acpi_get_mem_attribute(phys));
}
#define acpi_os_ioremap acpi_os_ioremap
@ -129,7 +135,10 @@ static inline const char *acpi_get_enable_method(int cpu)
* for compatibility.
*/
#define acpi_disable_cmcff 1
pgprot_t arch_apei_get_mem_attribute(phys_addr_t addr);
static inline pgprot_t arch_apei_get_mem_attribute(phys_addr_t addr)
{
return __acpi_get_mem_attribute(addr);
}
#endif /* CONFIG_ACPI_APEI */
#ifdef CONFIG_ACPI_NUMA

11
arch/arm64/kernel/acpi.c
View File

@ -18,6 +18,7 @@
#include <linux/acpi.h>
#include <linux/bootmem.h>
#include <linux/cpumask.h>
#include <linux/efi.h>
#include <linux/efi-bgrt.h>
#include <linux/init.h>
#include <linux/irq.h>
@ -29,13 +30,9 @@
#include <asm/cputype.h>
#include <asm/cpu_ops.h>
#include <asm/pgtable.h>
#include <asm/smp_plat.h>
#ifdef CONFIG_ACPI_APEI
# include <linux/efi.h>
# include <asm/pgtable.h>
#endif
int acpi_noirq = 1; /* skip ACPI IRQ initialization */
int acpi_disabled = 1;
EXPORT_SYMBOL(acpi_disabled);
@ -239,8 +236,7 @@ done:
}
}
#ifdef CONFIG_ACPI_APEI
pgprot_t arch_apei_get_mem_attribute(phys_addr_t addr)
pgprot_t __acpi_get_mem_attribute(phys_addr_t addr)
{
/*
* According to "Table 8 Map: EFI memory types to AArch64 memory
@ -261,4 +257,3 @@ pgprot_t arch_apei_get_mem_attribute(phys_addr_t addr)
return __pgprot(PROT_NORMAL_NC);
return __pgprot(PROT_DEVICE_nGnRnE);
}
#endif