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
This commit is contained in:
Mike Rapoport
Borislav Petkov
parent
e14cfb3bdd
commit
a799c2bd29
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@ -645,18 +645,6 @@ static void __init trim_snb_memory(void)
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}
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}
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/*
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* Here we put platform-specific memory range workarounds, i.e.
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* memory known to be corrupt or otherwise in need to be reserved on
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* specific platforms.
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*
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* If this gets used more widely it could use a real dispatch mechanism.
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*/
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static void __init trim_platform_memory_ranges(void)
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{
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trim_snb_memory();
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}
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static void __init trim_bios_range(void)
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{
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/*
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@ -729,7 +717,38 @@ static void __init trim_low_memory_range(void)
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{
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memblock_reserve(0, ALIGN(reserve_low, PAGE_SIZE));
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}
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static void __init early_reserve_memory(void)
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{
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/*
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* Reserve the memory occupied by the kernel between _text and
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* __end_of_kernel_reserve symbols. Any kernel sections after the
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* __end_of_kernel_reserve symbol must be explicitly reserved with a
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* separate memblock_reserve() or they will be discarded.
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*/
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memblock_reserve(__pa_symbol(_text),
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(unsigned long)__end_of_kernel_reserve - (unsigned long)_text);
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/*
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* Make sure page 0 is always reserved because on systems with
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* L1TF its contents can be leaked to user processes.
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*/
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memblock_reserve(0, PAGE_SIZE);
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early_reserve_initrd();
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if (efi_enabled(EFI_BOOT))
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efi_memblock_x86_reserve_range();
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memblock_x86_reserve_range_setup_data();
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reserve_ibft_region();
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reserve_bios_regions();
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trim_snb_memory();
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trim_low_memory_range();
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}
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/*
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* Dump out kernel offset information on panic.
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*/
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@ -764,29 +783,6 @@ dump_kernel_offset(struct notifier_block *self, unsigned long v, void *p)
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void __init setup_arch(char **cmdline_p)
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{
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/*
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* Reserve the memory occupied by the kernel between _text and
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* __end_of_kernel_reserve symbols. Any kernel sections after the
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* __end_of_kernel_reserve symbol must be explicitly reserved with a
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* separate memblock_reserve() or they will be discarded.
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*/
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memblock_reserve(__pa_symbol(_text),
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(unsigned long)__end_of_kernel_reserve - (unsigned long)_text);
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/*
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* Make sure page 0 is always reserved because on systems with
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* L1TF its contents can be leaked to user processes.
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*/
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memblock_reserve(0, PAGE_SIZE);
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early_reserve_initrd();
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/*
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* At this point everything still needed from the boot loader
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* or BIOS or kernel text should be early reserved or marked not
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* RAM in e820. All other memory is free game.
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*/
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#ifdef CONFIG_X86_32
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memcpy(&boot_cpu_data, &new_cpu_data, sizeof(new_cpu_data));
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@ -910,8 +906,18 @@ void __init setup_arch(char **cmdline_p)
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parse_early_param();
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if (efi_enabled(EFI_BOOT))
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efi_memblock_x86_reserve_range();
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/*
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* Do some memory reservations *before* memory is added to
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* memblock, so memblock allocations won't overwrite it.
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* Do it after early param, so we could get (unlikely) panic from
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* serial.
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*
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* After this point everything still needed from the boot loader or
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* firmware or kernel text should be early reserved or marked not
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* RAM in e820. All other memory is free game.
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*/
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early_reserve_memory();
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#ifdef CONFIG_MEMORY_HOTPLUG
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/*
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* Memory used by the kernel cannot be hot-removed because Linux
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@ -938,9 +944,6 @@ void __init setup_arch(char **cmdline_p)
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x86_report_nx();
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/* after early param, so could get panic from serial */
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memblock_x86_reserve_range_setup_data();
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if (acpi_mps_check()) {
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#ifdef CONFIG_X86_LOCAL_APIC
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disable_apic = 1;
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@ -1032,8 +1035,6 @@ void __init setup_arch(char **cmdline_p)
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*/
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find_smp_config();
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reserve_ibft_region();
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early_alloc_pgt_buf();
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/*
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@ -1054,8 +1055,6 @@ void __init setup_arch(char **cmdline_p)
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*/
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sev_setup_arch();
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reserve_bios_regions();
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efi_fake_memmap();
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efi_find_mirror();
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efi_esrt_init();
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@ -1081,9 +1080,6 @@ void __init setup_arch(char **cmdline_p)
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reserve_real_mode();
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trim_platform_memory_ranges();
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trim_low_memory_range();
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init_mem_mapping();
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idt_setup_early_pf();
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