From 112eee5d06007dae561f14458bde7f2a4879ef4e Mon Sep 17 00:00:00 2001 From: Lianbo Jiang Date: Fri, 8 Nov 2019 17:00:27 +0800 Subject: x86/crash: Add a forward declaration of struct kimage MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Add a forward declaration of struct kimage to the crash.h header because future changes will invoke a crash-specific function from the realmode init path and the compiler will complain otherwise like this: In file included from arch/x86/realmode/init.c:11: ./arch/x86/include/asm/crash.h:5:32: warning: ‘struct kimage’ declared inside\ parameter list will not be visible outside of this definition or declaration 5 | int crash_load_segments(struct kimage *image); | ^~~~~~ ./arch/x86/include/asm/crash.h:6:37: warning: ‘struct kimage’ declared inside\ parameter list will not be visible outside of this definition or declaration 6 | int crash_copy_backup_region(struct kimage *image); | ^~~~~~ ./arch/x86/include/asm/crash.h:7:39: warning: ‘struct kimage’ declared inside\ parameter list will not be visible outside of this definition or declaration 7 | int crash_setup_memmap_entries(struct kimage *image, | [ bp: Rewrite the commit message. ] Reported-by: kbuild test robot Signed-off-by: Lianbo Jiang Signed-off-by: Borislav Petkov Cc: bhe@redhat.com Cc: d.hatayama@fujitsu.com Cc: dhowells@redhat.com Cc: dyoung@redhat.com Cc: ebiederm@xmission.com Cc: horms@verge.net.au Cc: "H. Peter Anvin" Cc: Ingo Molnar Cc: Jürgen Gross Cc: kexec@lists.infradead.org Cc: Thomas Gleixner Cc: Tom Lendacky Cc: vgoyal@redhat.com Cc: x86-ml Link: https://lkml.kernel.org/r/20191108090027.11082-4-lijiang@redhat.com Link: https://lkml.kernel.org/r/201910310233.EJRtTMWP%25lkp@intel.com --- arch/x86/include/asm/crash.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'arch/x86/include/asm') diff --git a/arch/x86/include/asm/crash.h b/arch/x86/include/asm/crash.h index 0acf5ee45a21..ef5638f641f2 100644 --- a/arch/x86/include/asm/crash.h +++ b/arch/x86/include/asm/crash.h @@ -2,6 +2,8 @@ #ifndef _ASM_X86_CRASH_H #define _ASM_X86_CRASH_H +struct kimage; + int crash_load_segments(struct kimage *image); int crash_copy_backup_region(struct kimage *image); int crash_setup_memmap_entries(struct kimage *image, -- cgit From 6f599d84231fd27e42f4ca2a786a6641e8cddf00 Mon Sep 17 00:00:00 2001 From: Lianbo Jiang Date: Fri, 8 Nov 2019 17:00:25 +0800 Subject: x86/kdump: Always reserve the low 1M when the crashkernel option is specified MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit On x86, purgatory() copies the first 640K of memory to a backup region because the kernel needs those first 640K for the real mode trampoline during boot, among others. However, when SME is enabled, the kernel cannot properly copy the old memory to the backup area but reads only its encrypted contents. The result is that the crash tool gets invalid pointers when parsing vmcore: crash> kmem -s|grep -i invalid kmem: dma-kmalloc-512: slab:ffffd77680001c00 invalid freepointer:a6086ac099f0c5a4 kmem: dma-kmalloc-512: slab:ffffd77680001c00 invalid freepointer:a6086ac099f0c5a4 crash> So reserve the remaining low 1M memory when the crashkernel option is specified (after reserving real mode memory) so that allocated memory does not fall into the low 1M area and thus the copying of the contents of the first 640k to a backup region in purgatory() can be avoided altogether. This way, it does not need to be included in crash dumps or used for anything except the trampolines that must live in the low 1M. [ bp: Heavily rewrite commit message, flip check logic in crash_reserve_low_1M().] Signed-off-by: Lianbo Jiang Signed-off-by: Borislav Petkov Cc: bhe@redhat.com Cc: Dave Young Cc: d.hatayama@fujitsu.com Cc: dhowells@redhat.com Cc: ebiederm@xmission.com Cc: horms@verge.net.au Cc: "H. Peter Anvin" Cc: Ingo Molnar Cc: Jürgen Gross Cc: kexec@lists.infradead.org Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Tom Lendacky Cc: vgoyal@redhat.com Cc: x86-ml Link: https://lkml.kernel.org/r/20191108090027.11082-2-lijiang@redhat.com Link: https://bugzilla.kernel.org/show_bug.cgi?id=204793 --- arch/x86/include/asm/crash.h | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'arch/x86/include/asm') diff --git a/arch/x86/include/asm/crash.h b/arch/x86/include/asm/crash.h index ef5638f641f2..88eadd08ad70 100644 --- a/arch/x86/include/asm/crash.h +++ b/arch/x86/include/asm/crash.h @@ -10,4 +10,10 @@ int crash_setup_memmap_entries(struct kimage *image, struct boot_params *params); void crash_smp_send_stop(void); +#ifdef CONFIG_KEXEC_CORE +void __init crash_reserve_low_1M(void); +#else +static inline void __init crash_reserve_low_1M(void) { } +#endif + #endif /* _ASM_X86_CRASH_H */ -- cgit From 7c321eb2b843bf25946100b7e2de4054f71ec068 Mon Sep 17 00:00:00 2001 From: Lianbo Jiang Date: Fri, 8 Nov 2019 17:00:26 +0800 Subject: x86/kdump: Remove the backup region handling MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit When the crashkernel kernel command line option is specified, the low 1M memory will always be reserved now. Therefore, it's not necessary to create a backup region anymore and also no need to copy the contents of the first 640k to it. Remove all the code related to handling that backup region. [ bp: Massage commit message. ] Signed-off-by: Lianbo Jiang Signed-off-by: Borislav Petkov Cc: bhe@redhat.com Cc: Dave Young Cc: d.hatayama@fujitsu.com Cc: dhowells@redhat.com Cc: ebiederm@xmission.com Cc: horms@verge.net.au Cc: "H. Peter Anvin" Cc: Ingo Molnar Cc: Jürgen Gross Cc: kexec@lists.infradead.org Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Tom Lendacky Cc: vgoyal@redhat.com Cc: x86-ml Link: https://lkml.kernel.org/r/20191108090027.11082-3-lijiang@redhat.com --- arch/x86/include/asm/kexec.h | 10 ---------- arch/x86/include/asm/purgatory.h | 10 ---------- 2 files changed, 20 deletions(-) (limited to 'arch/x86/include/asm') diff --git a/arch/x86/include/asm/kexec.h b/arch/x86/include/asm/kexec.h index 5e7d6b46de97..6802c59e8252 100644 --- a/arch/x86/include/asm/kexec.h +++ b/arch/x86/include/asm/kexec.h @@ -66,10 +66,6 @@ struct kimage; # define KEXEC_ARCH KEXEC_ARCH_X86_64 #endif -/* Memory to backup during crash kdump */ -#define KEXEC_BACKUP_SRC_START (0UL) -#define KEXEC_BACKUP_SRC_END (640 * 1024UL - 1) /* 640K */ - /* * This function is responsible for capturing register states if coming * via panic otherwise just fix up the ss and sp if coming via kernel @@ -154,12 +150,6 @@ struct kimage_arch { pud_t *pud; pmd_t *pmd; pte_t *pte; - /* Details of backup region */ - unsigned long backup_src_start; - unsigned long backup_src_sz; - - /* Physical address of backup segment */ - unsigned long backup_load_addr; /* Core ELF header buffer */ void *elf_headers; diff --git a/arch/x86/include/asm/purgatory.h b/arch/x86/include/asm/purgatory.h index 92c34e517da1..5528e9325049 100644 --- a/arch/x86/include/asm/purgatory.h +++ b/arch/x86/include/asm/purgatory.h @@ -6,16 +6,6 @@ #include extern void purgatory(void); -/* - * These forward declarations serve two purposes: - * - * 1) Make sparse happy when checking arch/purgatory - * 2) Document that these are required to be global so the symbol - * lookup in kexec works - */ -extern unsigned long purgatory_backup_dest; -extern unsigned long purgatory_backup_src; -extern unsigned long purgatory_backup_sz; #endif /* __ASSEMBLY__ */ #endif /* _ASM_PURGATORY_H */ -- cgit