diff options
author | Mike Rapoport <rppt@linux.ibm.com> | 2021-03-02 12:04:05 +0200 |
---|---|---|
committer | Borislav Petkov <bp@suse.de> | 2021-03-23 17:13:17 +0100 |
commit | a799c2bd29d19c565f37fa038b31a0a1d44d0e4d (patch) | |
tree | 4f83ab3aa674911e59615c5378f46b8c6c68c224 | |
parent | e14cfb3bdd0f82147d09e9f46bedda6302f28ee1 (diff) |
x86/setup: Consolidate early memory reservations
The early reservations of memory areas used by the firmware, bootloader,
kernel text and data are spread over setup_arch(). Moreover, some of them
happen *after* memblock allocations, e.g trim_platform_memory_ranges() and
trim_low_memory_range() are called after reserve_real_mode() that allocates
memory.
There was no corruption of these memory regions because memblock always
allocates memory either from the end of memory (in top-down mode) or above
the kernel image (in bottom-up mode). However, the bottom up mode is going
to be updated to span the entire memory [1] to avoid limitations caused by
KASLR.
Consolidate early memory reservations in a dedicated function to improve
robustness against future changes. Having the early reservations in one
place also makes it clearer what memory must be reserved before memblock
allocations are allowed.
Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Baoquan He <bhe@redhat.com>
Acked-by: Borislav Petkov <bp@suse.de>
Acked-by: David Hildenbrand <david@redhat.com>
Link: [1] https://lore.kernel.org/lkml/20201217201214.3414100-2-guro@fb.com
Link: https://lkml.kernel.org/r/20210302100406.22059-2-rppt@kernel.org
-rw-r--r-- | arch/x86/kernel/setup.c | 92 |
1 files changed, 44 insertions, 48 deletions
diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c index d883176ef2ce..3e3c6036b023 100644 --- a/arch/x86/kernel/setup.c +++ b/arch/x86/kernel/setup.c @@ -645,18 +645,6 @@ static void __init trim_snb_memory(void) } } -/* - * Here we put platform-specific memory range workarounds, i.e. - * memory known to be corrupt or otherwise in need to be reserved on - * specific platforms. - * - * If this gets used more widely it could use a real dispatch mechanism. - */ -static void __init trim_platform_memory_ranges(void) -{ - trim_snb_memory(); -} - static void __init trim_bios_range(void) { /* @@ -729,7 +717,38 @@ static void __init trim_low_memory_range(void) { memblock_reserve(0, ALIGN(reserve_low, PAGE_SIZE)); } - + +static void __init early_reserve_memory(void) +{ + /* + * Reserve the memory occupied by the kernel between _text and + * __end_of_kernel_reserve symbols. Any kernel sections after the + * __end_of_kernel_reserve symbol must be explicitly reserved with a + * separate memblock_reserve() or they will be discarded. + */ + memblock_reserve(__pa_symbol(_text), + (unsigned long)__end_of_kernel_reserve - (unsigned long)_text); + + /* + * Make sure page 0 is always reserved because on systems with + * L1TF its contents can be leaked to user processes. + */ + memblock_reserve(0, PAGE_SIZE); + + early_reserve_initrd(); + + if (efi_enabled(EFI_BOOT)) + efi_memblock_x86_reserve_range(); + + memblock_x86_reserve_range_setup_data(); + + reserve_ibft_region(); + reserve_bios_regions(); + + trim_snb_memory(); + trim_low_memory_range(); +} + /* * Dump out kernel offset information on panic. */ @@ -764,29 +783,6 @@ dump_kernel_offset(struct notifier_block *self, unsigned long v, void *p) void __init setup_arch(char **cmdline_p) { - /* - * Reserve the memory occupied by the kernel between _text and - * __end_of_kernel_reserve symbols. Any kernel sections after the - * __end_of_kernel_reserve symbol must be explicitly reserved with a - * separate memblock_reserve() or they will be discarded. - */ - memblock_reserve(__pa_symbol(_text), - (unsigned long)__end_of_kernel_reserve - (unsigned long)_text); - - /* - * Make sure page 0 is always reserved because on systems with - * L1TF its contents can be leaked to user processes. - */ - memblock_reserve(0, PAGE_SIZE); - - early_reserve_initrd(); - - /* - * At this point everything still needed from the boot loader - * or BIOS or kernel text should be early reserved or marked not - * RAM in e820. All other memory is free game. - */ - #ifdef CONFIG_X86_32 memcpy(&boot_cpu_data, &new_cpu_data, sizeof(new_cpu_data)); @@ -910,8 +906,18 @@ void __init setup_arch(char **cmdline_p) parse_early_param(); - if (efi_enabled(EFI_BOOT)) - efi_memblock_x86_reserve_range(); + /* + * Do some memory reservations *before* memory is added to + * memblock, so memblock allocations won't overwrite it. + * Do it after early param, so we could get (unlikely) panic from + * serial. + * + * After this point everything still needed from the boot loader or + * firmware or kernel text should be early reserved or marked not + * RAM in e820. All other memory is free game. + */ + early_reserve_memory(); + #ifdef CONFIG_MEMORY_HOTPLUG /* * Memory used by the kernel cannot be hot-removed because Linux @@ -938,9 +944,6 @@ void __init setup_arch(char **cmdline_p) x86_report_nx(); - /* after early param, so could get panic from serial */ - memblock_x86_reserve_range_setup_data(); - if (acpi_mps_check()) { #ifdef CONFIG_X86_LOCAL_APIC disable_apic = 1; @@ -1032,8 +1035,6 @@ void __init setup_arch(char **cmdline_p) */ find_smp_config(); - reserve_ibft_region(); - early_alloc_pgt_buf(); /* @@ -1054,8 +1055,6 @@ void __init setup_arch(char **cmdline_p) */ sev_setup_arch(); - reserve_bios_regions(); - efi_fake_memmap(); efi_find_mirror(); efi_esrt_init(); @@ -1081,9 +1080,6 @@ void __init setup_arch(char **cmdline_p) reserve_real_mode(); - trim_platform_memory_ranges(); - trim_low_memory_range(); - init_mem_mapping(); idt_setup_early_pf(); |