From 09ffcb0d718a0b100f0bed029b830987ecf53fab Mon Sep 17 00:00:00 2001 From: AKASHI Takahiro Date: Mon, 23 Jul 2018 10:57:32 +0900 Subject: [PATCH] arm64: acpi: fix alignment fault in accessing ACPI 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...) [] acpi_ns_lookup+0x25c/0x3c0 [] acpi_ds_load1_begin_op+0xa4/0x294 [] acpi_ps_build_named_op+0xc4/0x198 [] acpi_ps_create_op+0x14c/0x270 [] acpi_ps_parse_loop+0x188/0x5c8 [] acpi_ps_parse_aml+0xb0/0x2b8 [] acpi_ns_one_complete_parse+0x144/0x184 [] acpi_ns_parse_table+0x48/0x68 [] acpi_ns_load_table+0x4c/0xdc [] acpi_tb_load_namespace+0xe4/0x264 [] acpi_load_tables+0x48/0xc0 [] acpi_early_init+0x9c/0xd0 [] 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 Reviewed-by: James Morse Reviewed-by: Ard Biesheuvel Reported-by and Tested-by: Bhupesh Sharma Signed-off-by: Will Deacon --- arch/arm64/include/asm/acpi.h | 23 ++++++++++++++++------- arch/arm64/kernel/acpi.c | 11 +++-------- 2 files changed, 19 insertions(+), 15 deletions(-) diff --git a/arch/arm64/include/asm/acpi.h b/arch/arm64/include/asm/acpi.h index d1c290f29b6f..709208dfdc8b 100644 --- a/arch/arm64/include/asm/acpi.h +++ b/arch/arm64/include/asm/acpi.h @@ -12,10 +12,12 @@ #ifndef _ASM_ACPI_H #define _ASM_ACPI_H +#include #include #include #include +#include #include #include @@ -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) { + /* For normal memory we already have a cacheable mapping. */ + if (memblock_is_map_memory(phys)) + return (void __iomem *)__phys_to_virt(phys); + /* - * EFI's reserve_regions() call adds memory with the WB attribute - * to memblock via early_init_dt_add_memory_arch(). + * We should still honor the memory's attribute here because + * crash dump kernel possibly excludes some ACPI (reclaim) + * regions from memblock list. */ - if (!memblock_is_memory(phys)) - return ioremap(phys, size); - - return ioremap_cache(phys, size); + 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 diff --git a/arch/arm64/kernel/acpi.c b/arch/arm64/kernel/acpi.c index 7b09487ff8fb..ed46dc188b22 100644 --- a/arch/arm64/kernel/acpi.c +++ b/arch/arm64/kernel/acpi.c @@ -18,6 +18,7 @@ #include #include #include +#include #include #include #include @@ -29,13 +30,9 @@ #include #include +#include #include -#ifdef CONFIG_ACPI_APEI -# include -# include -#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 -- 2.39.5