lkml.org 
[lkml]   [2019]   [Dec]   [31]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    Subject[PATCH v2 4/4] efi: Fix handling of multiple efi_fake_mem= entries
    From
    Date
    Dave noticed that when specifying multiple efi_fake_mem= entries only
    the last entry was successfully being reflected in the efi memory map.
    This is due to the fact that the efi_memmap_insert() is being called
    multiple times, but on successive invocations the insertion should be
    applied to the last new memmap rather than the original map at
    efi_fake_memmap() entry.

    Rework efi_fake_memmap() to install the new memory map after each
    efi_fake_mem= entry is parsed.

    This also fixes an issue in efi_fake_memmap() that caused it to litter
    emtpy entries into the end of the efi memory map. The empty entry causes
    efi_memmap_insert() to attempt more memmap splits / copies than
    efi_memmap_split_count() accounted for when sizing the new map.

    BUG: unable to handle page fault for address: ffffffffff281000
    [..]
    RIP: 0010:efi_memmap_insert+0x11d/0x191
    [..]
    Call Trace:
    ? bgrt_init+0xbe/0xbe
    ? efi_arch_mem_reserve+0x1cb/0x228
    ? acpi_parse_bgrt+0xa/0xd
    ? acpi_table_parse+0x86/0xb8
    ? acpi_boot_init+0x494/0x4e3
    ? acpi_parse_x2apic+0x87/0x87
    ? setup_acpi_sci+0xa2/0xa2
    ? setup_arch+0x8db/0x9e1
    ? start_kernel+0x6a/0x547
    ? secondary_startup_64+0xb6/0xc0

    Commit af1648984828 "x86/efi: Update e820 with reserved EFI boot
    services data to fix kexec breakage" is listed in Fixes: since it
    introduces more occurrences where efi_memmap_insert() is invoked after
    an efi_fake_mem= configuration has been parsed. Previously the side
    effects of vestigial empty entries were benign, but with commit
    af1648984828 that follow-on efi_memmap_insert() invocation triggers the
    above crash signature.

    Fixes: 0f96a99dab36 ("efi: Add 'efi_fake_mem' boot option")
    Fixes: af1648984828 ("x86/efi: Update e820 with reserved EFI boot services...")
    Link: https://lore.kernel.org/r/20191231014630.GA24942@dhcp-128-65.nay.redhat.com
    Reported-by: Dave Young <dyoung@redhat.com>
    Cc: Taku Izumi <izumi.taku@jp.fujitsu.com>
    Cc: Michael Weiser <michael@weiser.dinsnail.net>
    Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
    Cc: Thomas Gleixner <tglx@linutronix.de>
    Cc: Ingo Molnar <mingo@kernel.org>
    Signed-off-by: Dan Williams <dan.j.williams@intel.com>
    ---
    drivers/firmware/efi/fake_mem.c | 32 +++++++++++++++++---------------
    drivers/firmware/efi/memmap.c | 2 +-
    include/linux/efi.h | 2 ++
    3 files changed, 20 insertions(+), 16 deletions(-)

    diff --git a/drivers/firmware/efi/fake_mem.c b/drivers/firmware/efi/fake_mem.c
    index 7e53e5520548..68d752d8af21 100644
    --- a/drivers/firmware/efi/fake_mem.c
    +++ b/drivers/firmware/efi/fake_mem.c
    @@ -34,26 +34,17 @@ static int __init cmp_fake_mem(const void *x1, const void *x2)
    return 0;
    }

    -void __init efi_fake_memmap(void)
    +static void __init efi_fake_range(struct efi_mem_range *efi_range)
    {
    int new_nr_map = efi.memmap.nr_map;
    efi_memory_desc_t *md;
    phys_addr_t new_memmap_phy;
    unsigned long flags = 0;
    void *new_memmap;
    - int i;
    -
    - if (!efi_enabled(EFI_MEMMAP) || !nr_fake_mem)
    - return;

    /* count up the number of EFI memory descriptor */
    - for (i = 0; i < nr_fake_mem; i++) {
    - for_each_efi_memory_desc(md) {
    - struct range *r = &efi_fake_mems[i].range;
    -
    - new_nr_map += efi_memmap_split_count(md, r);
    - }
    - }
    + for_each_efi_memory_desc(md)
    + new_nr_map += efi_memmap_split_count(md, &efi_range->range);

    /* allocate memory for new EFI memmap */
    new_memmap_phy = efi_memmap_alloc(new_nr_map, &flags);
    @@ -64,17 +55,28 @@ void __init efi_fake_memmap(void)
    new_memmap = early_memremap(new_memmap_phy,
    efi.memmap.desc_size * new_nr_map);
    if (!new_memmap) {
    - memblock_free(new_memmap_phy, efi.memmap.desc_size * new_nr_map);
    + __efi_memmap_free(new_memmap_phy,
    + efi.memmap.desc_size * new_nr_map, flags);
    return;
    }

    - for (i = 0; i < nr_fake_mem; i++)
    - efi_memmap_insert(&efi.memmap, new_memmap, &efi_fake_mems[i]);
    + efi_memmap_insert(&efi.memmap, new_memmap, efi_range);

    /* swap into new EFI memmap */
    early_memunmap(new_memmap, efi.memmap.desc_size * new_nr_map);

    efi_memmap_install(new_memmap_phy, new_nr_map, flags);
    +}
    +
    +void __init efi_fake_memmap(void)
    +{
    + int i;
    +
    + if (!efi_enabled(EFI_MEMMAP) || !nr_fake_mem)
    + return;
    +
    + for (i = 0; i < nr_fake_mem; i++)
    + efi_fake_range(&efi_fake_mems[i]);

    /* print new EFI memmap */
    efi_print_memmap();
    diff --git a/drivers/firmware/efi/memmap.c b/drivers/firmware/efi/memmap.c
    index 188ab3cd5c52..de66c2a0e8f8 100644
    --- a/drivers/firmware/efi/memmap.c
    +++ b/drivers/firmware/efi/memmap.c
    @@ -29,7 +29,7 @@ static phys_addr_t __init __efi_memmap_alloc_late(unsigned long size)
    return PFN_PHYS(page_to_pfn(p));
    }

    -static void __init __efi_memmap_free(u64 phys, unsigned long size, unsigned long flags)
    +void __init __efi_memmap_free(u64 phys, unsigned long size, unsigned long flags)
    {
    if (WARN_ON(slab_is_available() && (flags & EFI_MEMMAP_MEMBLOCK)))
    return;
    diff --git a/include/linux/efi.h b/include/linux/efi.h
    index fa2668a992ae..6ae31e064321 100644
    --- a/include/linux/efi.h
    +++ b/include/linux/efi.h
    @@ -1061,6 +1061,8 @@ extern void __iomem *efi_lookup_mapped_addr(u64 phys_addr);

    extern phys_addr_t __init efi_memmap_alloc(unsigned int num_entries,
    unsigned long *flags);
    +extern void __efi_memmap_free(u64 phys, unsigned long size,
    + unsigned long flags);
    extern int __init efi_memmap_init_early(struct efi_memory_map_data *data);
    extern int __init efi_memmap_init_late(phys_addr_t addr, unsigned long size);
    extern void __init efi_memmap_unmap(void);
    \
     
     \ /
      Last update: 2019-12-31 23:21    [W:2.634 / U:0.012 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site