From 203e9e41219b4e7357104e525e91ac609fba2c6c Mon Sep 17 00:00:00 2001 From: Xunlei Pang Date: Wed, 12 Jul 2017 14:33:14 -0700 Subject: kexec: move vmcoreinfo out of the kernel's .bss section As Eric said, "what we need to do is move the variable vmcoreinfo_note out of the kernel's .bss section. And modify the code to regenerate and keep this information in something like the control page. Definitely something like this needs a page all to itself, and ideally far away from any other kernel data structures. I clearly was not watching closely the data someone decided to keep this silly thing in the kernel's .bss section." This patch allocates extra pages for these vmcoreinfo_XXX variables, one advantage is that it enhances some safety of vmcoreinfo, because vmcoreinfo now is kept far away from other kernel data structures. Link: http://lkml.kernel.org/r/1493281021-20737-1-git-send-email-xlpang@redhat.com Signed-off-by: Xunlei Pang Tested-by: Michael Holzheu Reviewed-by: Juergen Gross Suggested-by: Eric Biederman Cc: Benjamin Herrenschmidt Cc: Dave Young Cc: Hari Bathini Cc: Mahesh Salgaonkar Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/ia64/kernel/machine_kexec.c | 5 ----- arch/s390/kernel/machine_kexec.c | 1 + arch/s390/kernel/setup.c | 6 ------ arch/x86/kernel/crash.c | 2 +- arch/x86/xen/mmu_pv.c | 4 ++-- 5 files changed, 4 insertions(+), 14 deletions(-) (limited to 'arch') diff --git a/arch/ia64/kernel/machine_kexec.c b/arch/ia64/kernel/machine_kexec.c index 599507bcec91..c14815dca747 100644 --- a/arch/ia64/kernel/machine_kexec.c +++ b/arch/ia64/kernel/machine_kexec.c @@ -163,8 +163,3 @@ void arch_crash_save_vmcoreinfo(void) #endif } -phys_addr_t paddr_vmcoreinfo_note(void) -{ - return ia64_tpa((unsigned long)(char *)&vmcoreinfo_note); -} - diff --git a/arch/s390/kernel/machine_kexec.c b/arch/s390/kernel/machine_kexec.c index 49a6bd45957b..3d0b14afa232 100644 --- a/arch/s390/kernel/machine_kexec.c +++ b/arch/s390/kernel/machine_kexec.c @@ -246,6 +246,7 @@ void arch_crash_save_vmcoreinfo(void) VMCOREINFO_SYMBOL(lowcore_ptr); VMCOREINFO_SYMBOL(high_memory); VMCOREINFO_LENGTH(lowcore_ptr, NR_CPUS); + mem_assign_absolute(S390_lowcore.vmcore_info, paddr_vmcoreinfo_note()); } void machine_shutdown(void) diff --git a/arch/s390/kernel/setup.c b/arch/s390/kernel/setup.c index 3ae756c0db3d..3d1d808ea8a9 100644 --- a/arch/s390/kernel/setup.c +++ b/arch/s390/kernel/setup.c @@ -496,11 +496,6 @@ static void __init setup_memory_end(void) pr_notice("The maximum memory size is %luMB\n", memory_end >> 20); } -static void __init setup_vmcoreinfo(void) -{ - mem_assign_absolute(S390_lowcore.vmcore_info, paddr_vmcoreinfo_note()); -} - #ifdef CONFIG_CRASH_DUMP /* @@ -939,7 +934,6 @@ void __init setup_arch(char **cmdline_p) #endif setup_resources(); - setup_vmcoreinfo(); setup_lowcore(); smp_fill_possible_mask(); cpu_detect_mhz_feature(); diff --git a/arch/x86/kernel/crash.c b/arch/x86/kernel/crash.c index 22217ece26c8..44404e2307bb 100644 --- a/arch/x86/kernel/crash.c +++ b/arch/x86/kernel/crash.c @@ -457,7 +457,7 @@ static int prepare_elf64_headers(struct crash_elf_data *ced, bufp += sizeof(Elf64_Phdr); phdr->p_type = PT_NOTE; phdr->p_offset = phdr->p_paddr = paddr_vmcoreinfo_note(); - phdr->p_filesz = phdr->p_memsz = sizeof(vmcoreinfo_note); + phdr->p_filesz = phdr->p_memsz = VMCOREINFO_NOTE_SIZE; (ehdr->e_phnum)++; #ifdef CONFIG_X86_64 diff --git a/arch/x86/xen/mmu_pv.c b/arch/x86/xen/mmu_pv.c index 1d7a7213a310..cab28cf2cffb 100644 --- a/arch/x86/xen/mmu_pv.c +++ b/arch/x86/xen/mmu_pv.c @@ -2693,8 +2693,8 @@ EXPORT_SYMBOL_GPL(xen_destroy_contiguous_region); phys_addr_t paddr_vmcoreinfo_note(void) { if (xen_pv_domain()) - return virt_to_machine(&vmcoreinfo_note).maddr; + return virt_to_machine(vmcoreinfo_note).maddr; else - return __pa_symbol(&vmcoreinfo_note); + return __pa(vmcoreinfo_note); } #endif /* CONFIG_KEXEC_CORE */ -- cgit v1.2.3