From mboxrd@z Thu Jan 1 00:00:00 1970 From: Chao Gao Subject: [PATCH] x86/efi: Add necessary checks before iterating over efi.memmap Date: Tue, 13 Sep 2016 11:28:15 +0800 Message-ID: <20160913032813.GA11652@localhost.localdomain> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline Sender: linux-efi-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: linux-efi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org Cc: Matt Fleming , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , x86-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org List-Id: linux-efi@vger.kernel.org Commit 78ce248f (efi: Iterate over efi.memmap in for_each_efi_memory_desc()) replaces the old loop by for_each_efi_memory_desc() which will encounter #PF when efi.memap are not initialized. In boot process, xen set EFI_PARAVIRT in xen_efi_init() before setup_arch() is called. This leads efi_memmap_init() will not initialize structures related to efi.memmap. However, the following functions e.g. efi_find_mirror(), efi_print_memmap() and efi_free_boot_services() access efi.memmap without necessary checks. kernel and xen crash in this case. After adding these checks, xen and kernel boot up normally. Signed-off-by: Chao Gao --- arch/x86/platform/efi/efi.c | 6 ++++++ arch/x86/platform/efi/quirks.c | 3 +++ 2 files changed, 9 insertions(+) diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c index 1fbb408..68966dc 100644 --- a/arch/x86/platform/efi/efi.c +++ b/arch/x86/platform/efi/efi.c @@ -102,6 +102,9 @@ void __init efi_find_mirror(void) efi_memory_desc_t *md; u64 mirror_size = 0, total_size = 0; + if (efi_enabled(EFI_PARAVIRT)) + return; + for_each_efi_memory_desc(md) { unsigned long long start = md->phys_addr; unsigned long long size = md->num_pages << EFI_PAGE_SHIFT; @@ -207,6 +210,9 @@ void __init efi_print_memmap(void) efi_memory_desc_t *md; int i = 0; + if (efi_enabled(EFI_PARAVIRT)) + return; + for_each_efi_memory_desc(md) { char buf[64]; diff --git a/arch/x86/platform/efi/quirks.c b/arch/x86/platform/efi/quirks.c index 89d1146..4fa1e4d 100644 --- a/arch/x86/platform/efi/quirks.c +++ b/arch/x86/platform/efi/quirks.c @@ -251,6 +251,9 @@ void __init efi_free_boot_services(void) { efi_memory_desc_t *md; + if (efi_enabled(EFI_PARAVIRT)) + return; + for_each_efi_memory_desc(md) { unsigned long long start = md->phys_addr; unsigned long long size = md->num_pages << EFI_PAGE_SHIFT; -- 1.8.3.1