From d2b6dc61a8dd3c429609b993778cb54e75a5c5f0 Mon Sep 17 00:00:00 2001 From: Andy Lutomirski Date: Mon, 8 May 2017 17:09:10 -0700 Subject: x86/boot/32: Fix UP boot on Quark and possibly other platforms This partially reverts commit: 23b2a4ddebdd17f ("x86/boot/32: Defer resyncing initial_page_table until per-cpu is set up") That commit had one definite bug and one potential bug. The definite bug is that setup_per_cpu_areas() uses a differnet generic implementation on UP kernels, so initial_page_table never got resynced. This was fine for access to percpu data (it's in the identity map on UP), but it breaks other users of initial_page_table. The potential bug is that helpers like efi_init() would be called before the tables were synced. Avoid both problems by just syncing the page tables in setup_arch() *and* setup_per_cpu_areas(). Reported-by: Jan Kiszka Signed-off-by: Andy Lutomirski Cc: Andy Shevchenko Cc: Ard Biesheuvel Cc: Boris Ostrovsky Cc: Borislav Petkov Cc: Brian Gerst Cc: Denys Vlasenko Cc: Josh Poimboeuf Cc: Juergen Gross Cc: Linus Torvalds Cc: Matt Fleming Cc: Peter Zijlstra Cc: Thomas Garnier Cc: Thomas Gleixner Cc: linux-efi@vger.kernel.org Signed-off-by: Ingo Molnar --- arch/x86/kernel/setup.c | 15 +++++++++++++++ arch/x86/kernel/setup_percpu.c | 10 +++++----- 2 files changed, 20 insertions(+), 5 deletions(-) (limited to 'arch/x86') diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c index 603a1669a2ec..0b4d3c686b1e 100644 --- a/arch/x86/kernel/setup.c +++ b/arch/x86/kernel/setup.c @@ -1225,6 +1225,21 @@ void __init setup_arch(char **cmdline_p) kasan_init(); +#ifdef CONFIG_X86_32 + /* sync back kernel address range */ + clone_pgd_range(initial_page_table + KERNEL_PGD_BOUNDARY, + swapper_pg_dir + KERNEL_PGD_BOUNDARY, + KERNEL_PGD_PTRS); + + /* + * sync back low identity map too. It is used for example + * in the 32-bit EFI stub. + */ + clone_pgd_range(initial_page_table, + swapper_pg_dir + KERNEL_PGD_BOUNDARY, + min(KERNEL_PGD_PTRS, KERNEL_PGD_BOUNDARY)); +#endif + tboot_probe(); map_vsyscall(); diff --git a/arch/x86/kernel/setup_percpu.c b/arch/x86/kernel/setup_percpu.c index bb1e8cc0bc84..10edd1e69a68 100644 --- a/arch/x86/kernel/setup_percpu.c +++ b/arch/x86/kernel/setup_percpu.c @@ -291,11 +291,11 @@ void __init setup_per_cpu_areas(void) #ifdef CONFIG_X86_32 /* - * Sync back kernel address range. We want to make sure that - * all kernel mappings, including percpu mappings, are available - * in the smpboot asm. We can't reliably pick up percpu - * mappings using vmalloc_fault(), because exception dispatch - * needs percpu data. + * Sync back kernel address range again. We already did this in + * setup_arch(), but percpu data also needs to be available in + * the smpboot asm. We can't reliably pick up percpu mappings + * using vmalloc_fault(), because exception dispatch needs + * percpu data. */ clone_pgd_range(initial_page_table + KERNEL_PGD_BOUNDARY, swapper_pg_dir + KERNEL_PGD_BOUNDARY, -- cgit v1.2.3