From 7e0dabd3010d6041ee0a952c1146b2150a11f1be Mon Sep 17 00:00:00 2001 From: Sai Praneeth Prakhya Date: Thu, 29 Nov 2018 18:12:23 +0100 Subject: x86/mm/pageattr: Introduce helper function to unmap EFI boot services Ideally, after kernel assumes control of the platform, firmware shouldn't access EFI boot services code/data regions. But, it's noticed that this is not so true in many x86 platforms. Hence, during boot, kernel reserves EFI boot services code/data regions [1] and maps [2] them to efi_pgd so that call to set_virtual_address_map() doesn't fail. After returning from set_virtual_address_map(), kernel frees the reserved regions [3] but they still remain mapped. Hence, introduce kernel_unmap_pages_in_pgd() which will later be used to unmap EFI boot services code/data regions. While at it modify kernel_map_pages_in_pgd() by: 1. Adding __init modifier because it's always used *only* during boot. 2. Add a warning if it's used after SMP is initialized because it uses __flush_tlb_all() which flushes mappings only on current CPU. Unmapping EFI boot services code/data regions will result in clearing PAGE_PRESENT bit and it shouldn't bother L1TF cases because it's already handled by protnone_mask() at arch/x86/include/asm/pgtable-invert.h. [1] efi_reserve_boot_services() [2] efi_map_region() -> __map_region() -> kernel_map_pages_in_pgd() [3] efi_free_boot_services() Signed-off-by: Sai Praneeth Prakhya Signed-off-by: Ard Biesheuvel Reviewed-by: Thomas Gleixner Cc: Andy Lutomirski Cc: Arend van Spriel Cc: Bhupesh Sharma Cc: Borislav Petkov Cc: Dave Hansen Cc: Eric Snowberg Cc: Hans de Goede Cc: Joe Perches Cc: Jon Hunter Cc: Julien Thierry Cc: Linus Torvalds Cc: Marc Zyngier Cc: Matt Fleming Cc: Nathan Chancellor Cc: Peter Zijlstra Cc: Sedat Dilek Cc: YiFei Zhu Cc: linux-efi@vger.kernel.org Link: http://lkml.kernel.org/r/20181129171230.18699-5-ard.biesheuvel@linaro.org Signed-off-by: Ingo Molnar --- arch/x86/include/asm/pgtable_types.h | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) (limited to 'arch/x86/include') diff --git a/arch/x86/include/asm/pgtable_types.h b/arch/x86/include/asm/pgtable_types.h index 106b7d0e2dae..d6ff0bbdb394 100644 --- a/arch/x86/include/asm/pgtable_types.h +++ b/arch/x86/include/asm/pgtable_types.h @@ -564,8 +564,12 @@ extern pte_t *lookup_address_in_pgd(pgd_t *pgd, unsigned long address, unsigned int *level); extern pmd_t *lookup_pmd_address(unsigned long address); extern phys_addr_t slow_virt_to_phys(void *__address); -extern int kernel_map_pages_in_pgd(pgd_t *pgd, u64 pfn, unsigned long address, - unsigned numpages, unsigned long page_flags); +extern int __init kernel_map_pages_in_pgd(pgd_t *pgd, u64 pfn, + unsigned long address, + unsigned numpages, + unsigned long page_flags); +extern int __init kernel_unmap_pages_in_pgd(pgd_t *pgd, unsigned long address, + unsigned long numpages); #endif /* !__ASSEMBLY__ */ #endif /* _ASM_X86_PGTABLE_DEFS_H */ -- cgit v1.2.3 From 47c33a095e1fae376d74b4160a0d73c1a4e73969 Mon Sep 17 00:00:00 2001 From: Sai Praneeth Prakhya Date: Thu, 29 Nov 2018 18:12:25 +0100 Subject: x86/efi: Move efi__boot_services() to arch/x86 efi__boot_services() are x86 specific quirks and as such should be in asm/efi.h, so move them from linux/efi.h. Also, call efi_free_boot_services() from __efi_enter_virtual_mode() as it is x86 specific call and ideally shouldn't be part of init/main.c Signed-off-by: Sai Praneeth Prakhya Signed-off-by: Ard Biesheuvel Acked-by: Thomas Gleixner Cc: Andy Lutomirski Cc: Arend van Spriel Cc: Bhupesh Sharma Cc: Borislav Petkov Cc: Dave Hansen Cc: Eric Snowberg Cc: Hans de Goede Cc: Joe Perches Cc: Jon Hunter Cc: Julien Thierry Cc: Linus Torvalds Cc: Marc Zyngier Cc: Matt Fleming Cc: Nathan Chancellor Cc: Peter Zijlstra Cc: Sedat Dilek Cc: YiFei Zhu Cc: linux-efi@vger.kernel.org Link: http://lkml.kernel.org/r/20181129171230.18699-7-ard.biesheuvel@linaro.org Signed-off-by: Ingo Molnar --- arch/x86/include/asm/efi.h | 2 ++ arch/x86/platform/efi/efi.c | 2 ++ include/linux/efi.h | 3 --- init/main.c | 4 ---- 4 files changed, 4 insertions(+), 7 deletions(-) (limited to 'arch/x86/include') diff --git a/arch/x86/include/asm/efi.h b/arch/x86/include/asm/efi.h index eea40d52ca78..d1e64ac80b9c 100644 --- a/arch/x86/include/asm/efi.h +++ b/arch/x86/include/asm/efi.h @@ -141,6 +141,8 @@ extern int __init efi_reuse_config(u64 tables, int nr_tables); extern void efi_delete_dummy_variable(void); extern void efi_switch_mm(struct mm_struct *mm); extern void efi_recover_from_page_fault(unsigned long phys_addr); +extern void efi_free_boot_services(void); +extern void efi_reserve_boot_services(void); struct efi_setup_data { u64 fw_vendor; diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c index 7ae939e353cd..e1cb01a22fa8 100644 --- a/arch/x86/platform/efi/efi.c +++ b/arch/x86/platform/efi/efi.c @@ -993,6 +993,8 @@ static void __init __efi_enter_virtual_mode(void) panic("EFI call to SetVirtualAddressMap() failed!"); } + efi_free_boot_services(); + /* * Now that EFI is in virtual mode, update the function * pointers in the runtime service table to the new virtual addresses. diff --git a/include/linux/efi.h b/include/linux/efi.h index 100ce4a4aff6..2b3b33c83b05 100644 --- a/include/linux/efi.h +++ b/include/linux/efi.h @@ -1000,13 +1000,11 @@ extern void efi_memmap_walk (efi_freemem_callback_t callback, void *arg); extern void efi_gettimeofday (struct timespec64 *ts); extern void efi_enter_virtual_mode (void); /* switch EFI to virtual mode, if possible */ #ifdef CONFIG_X86 -extern void efi_free_boot_services(void); extern efi_status_t efi_query_variable_store(u32 attributes, unsigned long size, bool nonblocking); extern void efi_find_mirror(void); #else -static inline void efi_free_boot_services(void) {} static inline efi_status_t efi_query_variable_store(u32 attributes, unsigned long size, @@ -1046,7 +1044,6 @@ extern void efi_mem_reserve(phys_addr_t addr, u64 size); extern int efi_mem_reserve_persistent(phys_addr_t addr, u64 size); extern void efi_initialize_iomem_resources(struct resource *code_resource, struct resource *data_resource, struct resource *bss_resource); -extern void efi_reserve_boot_services(void); extern int efi_get_fdt_params(struct efi_fdt_params *params); extern struct kobject *efi_kobj; diff --git a/init/main.c b/init/main.c index ee147103ba1b..ccefcd8e855f 100644 --- a/init/main.c +++ b/init/main.c @@ -737,10 +737,6 @@ asmlinkage __visible void __init start_kernel(void) arch_post_acpi_subsys_init(); sfi_init_late(); - if (efi_enabled(EFI_RUNTIME_SERVICES)) { - efi_free_boot_services(); - } - /* Do the rest non-__init'ed, we're now alive */ arch_call_rest_init(); } -- cgit v1.2.3