From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932630AbdDEJBq (ORCPT ); Wed, 5 Apr 2017 05:01:46 -0400 Received: from terminus.zytor.com ([65.50.211.136]:57997 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932653AbdDEJA0 (ORCPT ); Wed, 5 Apr 2017 05:00:26 -0400 Date: Wed, 5 Apr 2017 01:55:42 -0700 From: tip-bot for Ard Biesheuvel Message-ID: Cc: tglx@linutronix.de, torvalds@linux-foundation.org, matt@codeblueprint.co.uk, eugene@hp.com, hpa@zytor.com, linux-kernel@vger.kernel.org, mingo@kernel.org, ard.biesheuvel@linaro.org, leif.lindholm@linaro.org, roy.franz@cavium.com, peterz@infradead.org Reply-To: leif.lindholm@linaro.org, ard.biesheuvel@linaro.org, mingo@kernel.org, peterz@infradead.org, roy.franz@cavium.com, matt@codeblueprint.co.uk, eugene@hp.com, hpa@zytor.com, tglx@linutronix.de, torvalds@linux-foundation.org, linux-kernel@vger.kernel.org In-Reply-To: <20170404160245.27812-11-ard.biesheuvel@linaro.org> References: <20170404160245.27812-11-ard.biesheuvel@linaro.org> To: linux-tip-commits@vger.kernel.org Subject: [tip:efi/core] efi/arm32-stub: Allow boot-time allocations in the vmlinux region Git-Commit-ID: 0dee5fe386a3b51b63f5ac5aa3a23bc6ed385cae X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: 0dee5fe386a3b51b63f5ac5aa3a23bc6ed385cae Gitweb: http://git.kernel.org/tip/0dee5fe386a3b51b63f5ac5aa3a23bc6ed385cae Author: Ard Biesheuvel AuthorDate: Tue, 4 Apr 2017 17:02:44 +0100 Committer: Ingo Molnar CommitDate: Wed, 5 Apr 2017 09:27:52 +0200 efi/arm32-stub: Allow boot-time allocations in the vmlinux region The arm32 kernel decompresses itself to the base of DRAM unconditionally, and so it is the EFI stub's job to ensure that the region is available. Currently, we do this by creating an allocation there, and giving up if that fails. However, any boot services regions occupying this area are not an issue, given that the decompressor executes strictly after the stub calls ExitBootServices(). So let's try a bit harder to proceed if the initial allocation fails, and check whether any memory map entries occupying the region may be considered safe. Signed-off-by: Ard Biesheuvel Reviewed-by: Leif Lindholm Reviewed-by: Eugene Cohen Reviewed-by: Roy Franz Cc: Linus Torvalds Cc: Matt Fleming Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-efi@vger.kernel.org Link: http://lkml.kernel.org/r/20170404160245.27812-11-ard.biesheuvel@linaro.org Signed-off-by: Ingo Molnar --- drivers/firmware/efi/libstub/arm32-stub.c | 148 ++++++++++++++++++++++++++---- 1 file changed, 128 insertions(+), 20 deletions(-) diff --git a/drivers/firmware/efi/libstub/arm32-stub.c b/drivers/firmware/efi/libstub/arm32-stub.c index e1f0b28..18a8b5e 100644 --- a/drivers/firmware/efi/libstub/arm32-stub.c +++ b/drivers/firmware/efi/libstub/arm32-stub.c @@ -63,6 +63,132 @@ void free_screen_info(efi_system_table_t *sys_table_arg, struct screen_info *si) efi_call_early(free_pool, si); } +static efi_status_t reserve_kernel_base(efi_system_table_t *sys_table_arg, + unsigned long dram_base, + unsigned long *reserve_addr, + unsigned long *reserve_size) +{ + efi_physical_addr_t alloc_addr; + efi_memory_desc_t *memory_map; + unsigned long nr_pages, map_size, desc_size, buff_size; + efi_status_t status; + unsigned long l; + + struct efi_boot_memmap map = { + .map = &memory_map, + .map_size = &map_size, + .desc_size = &desc_size, + .desc_ver = NULL, + .key_ptr = NULL, + .buff_size = &buff_size, + }; + + /* + * Reserve memory for the uncompressed kernel image. This is + * all that prevents any future allocations from conflicting + * with the kernel. Since we can't tell from the compressed + * image how much DRAM the kernel actually uses (due to BSS + * size uncertainty) we allocate the maximum possible size. + * Do this very early, as prints can cause memory allocations + * that may conflict with this. + */ + alloc_addr = dram_base + MAX_UNCOMP_KERNEL_SIZE; + nr_pages = MAX_UNCOMP_KERNEL_SIZE / EFI_PAGE_SIZE; + status = efi_call_early(allocate_pages, EFI_ALLOCATE_MAX_ADDRESS, + EFI_BOOT_SERVICES_DATA, nr_pages, &alloc_addr); + if (status == EFI_SUCCESS) { + if (alloc_addr == dram_base) { + *reserve_addr = alloc_addr; + *reserve_size = MAX_UNCOMP_KERNEL_SIZE; + return EFI_SUCCESS; + } + /* + * If we end up here, the allocation succeeded but starts below + * dram_base. This can only occur if the real base of DRAM is + * not a multiple of 128 MB, in which case dram_base will have + * been rounded up. Since this implies that a part of the region + * was already occupied, we need to fall through to the code + * below to ensure that the existing allocations don't conflict. + * For this reason, we use EFI_BOOT_SERVICES_DATA above and not + * EFI_LOADER_DATA, which we wouldn't able to distinguish from + * allocations that we want to disallow. + */ + } + + /* + * If the allocation above failed, we may still be able to proceed: + * if the only allocations in the region are of types that will be + * released to the OS after ExitBootServices(), the decompressor can + * safely overwrite them. + */ + status = efi_get_memory_map(sys_table_arg, &map); + if (status != EFI_SUCCESS) { + pr_efi_err(sys_table_arg, + "reserve_kernel_base(): Unable to retrieve memory map.\n"); + return status; + } + + for (l = 0; l < map_size; l += desc_size) { + efi_memory_desc_t *desc; + u64 start, end; + + desc = (void *)memory_map + l; + start = desc->phys_addr; + end = start + desc->num_pages * EFI_PAGE_SIZE; + + /* Skip if entry does not intersect with region */ + if (start >= dram_base + MAX_UNCOMP_KERNEL_SIZE || + end <= dram_base) + continue; + + switch (desc->type) { + case EFI_BOOT_SERVICES_CODE: + case EFI_BOOT_SERVICES_DATA: + /* Ignore types that are released to the OS anyway */ + continue; + + case EFI_CONVENTIONAL_MEMORY: + /* + * Reserve the intersection between this entry and the + * region. + */ + start = max(start, (u64)dram_base); + end = min(end, (u64)dram_base + MAX_UNCOMP_KERNEL_SIZE); + + status = efi_call_early(allocate_pages, + EFI_ALLOCATE_ADDRESS, + EFI_LOADER_DATA, + (end - start) / EFI_PAGE_SIZE, + &start); + if (status != EFI_SUCCESS) { + pr_efi_err(sys_table_arg, + "reserve_kernel_base(): alloc failed.\n"); + goto out; + } + break; + + case EFI_LOADER_CODE: + case EFI_LOADER_DATA: + /* + * These regions may be released and reallocated for + * another purpose (including EFI_RUNTIME_SERVICE_DATA) + * at any time during the execution of the OS loader, + * so we cannot consider them as safe. + */ + default: + /* + * Treat any other allocation in the region as unsafe */ + status = EFI_OUT_OF_RESOURCES; + goto out; + } + } + + status = EFI_SUCCESS; +out: + efi_call_early(free_pool, memory_map); + return status; +} + efi_status_t handle_kernel_image(efi_system_table_t *sys_table, unsigned long *image_addr, unsigned long *image_size, @@ -71,10 +197,7 @@ efi_status_t handle_kernel_image(efi_system_table_t *sys_table, unsigned long dram_base, efi_loaded_image_t *image) { - unsigned long nr_pages; efi_status_t status; - /* Use alloc_addr to tranlsate between types */ - efi_physical_addr_t alloc_addr; /* * Verify that the DRAM base address is compatible with the ARM @@ -85,27 +208,12 @@ efi_status_t handle_kernel_image(efi_system_table_t *sys_table, */ dram_base = round_up(dram_base, SZ_128M); - /* - * Reserve memory for the uncompressed kernel image. This is - * all that prevents any future allocations from conflicting - * with the kernel. Since we can't tell from the compressed - * image how much DRAM the kernel actually uses (due to BSS - * size uncertainty) we allocate the maximum possible size. - * Do this very early, as prints can cause memory allocations - * that may conflict with this. - */ - alloc_addr = dram_base; - *reserve_size = MAX_UNCOMP_KERNEL_SIZE; - nr_pages = round_up(*reserve_size, EFI_PAGE_SIZE) / EFI_PAGE_SIZE; - status = sys_table->boottime->allocate_pages(EFI_ALLOCATE_ADDRESS, - EFI_LOADER_DATA, - nr_pages, &alloc_addr); + status = reserve_kernel_base(sys_table, dram_base, reserve_addr, + reserve_size); if (status != EFI_SUCCESS) { - *reserve_size = 0; pr_efi_err(sys_table, "Unable to allocate memory for uncompressed kernel.\n"); return status; } - *reserve_addr = alloc_addr; /* * Relocate the zImage, so that it appears in the lowest 128 MB