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    Subject[PATCH 01/11] x86/efi: Allocate e820 buffer before calling efi_exit_boot_service
    Date
    From: Eric Snowberg <eric.snowberg@oracle.com>

    Commit d64934019f6c ("x86/efi: Use efi_exit_boot_services()")
    introduced a regression on systems with large memory maps
    causing them to hang on boot. The first "goto get_map" that was removed
    from exit_boot insured there was enough room for the memory map when
    efi_call_early(exit_boot_services) was called. This happens when
    (nr_desc > ARRAY_SIZE(params->e820_table).

    Chain of events:
    exit_boot()
    efi_exit_boot_services()
    efi_get_memory_map <- at this point the mm can't grow over 8 desc
    priv_func()
    exit_boot_func()
    allocate_e820ext() <- new mm grows over 8 desc from e820 alloc
    efi_call_early(exit_boot_services) <- mm key doesn't match so retry
    efi_call_early(get_memory_map) <- not enough room for new mm
    system hangs

    This patch allocates the e820 buffer before calling efi_exit_boot_services
    and fixes the regression.

    Signed-off-by: Eric Snowberg <eric.snowberg@oracle.com>
    Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
    ---
    arch/x86/boot/compressed/eboot.c | 65 ++++++++++++++++++++------------
    1 file changed, 41 insertions(+), 24 deletions(-)

    diff --git a/arch/x86/boot/compressed/eboot.c b/arch/x86/boot/compressed/eboot.c
    index 8b4c5e001157..f7bad07bb251 100644
    --- a/arch/x86/boot/compressed/eboot.c
    +++ b/arch/x86/boot/compressed/eboot.c
    @@ -1,3 +1,4 @@
    +
    /* -----------------------------------------------------------------------
    *
    * Copyright 2011 Intel Corporation; author Matt Fleming
    @@ -634,37 +635,54 @@ static efi_status_t alloc_e820ext(u32 nr_desc, struct setup_data **e820ext,
    return status;
    }

    +static efi_status_t allocate_e820(struct boot_params *params,
    + struct setup_data **e820ext,
    + u32 *e820ext_size)
    +{
    + unsigned long map_size, desc_size, buff_size;
    + struct efi_boot_memmap boot_map;
    + efi_memory_desc_t *map;
    + efi_status_t status;
    + __u32 nr_desc;
    +
    + boot_map.map = &map;
    + boot_map.map_size = &map_size;
    + boot_map.desc_size = &desc_size;
    + boot_map.desc_ver = NULL;
    + boot_map.key_ptr = NULL;
    + boot_map.buff_size = &buff_size;
    +
    + status = efi_get_memory_map(sys_table, &boot_map);
    + if (status != EFI_SUCCESS)
    + return status;
    +
    + nr_desc = buff_size / desc_size;
    +
    + if (nr_desc > ARRAY_SIZE(params->e820_table)) {
    + u32 nr_e820ext = nr_desc - ARRAY_SIZE(params->e820_table);
    +
    + status = alloc_e820ext(nr_e820ext, e820ext, e820ext_size);
    + if (status != EFI_SUCCESS)
    + return status;
    + }
    +
    + return EFI_SUCCESS;
    +}
    +
    struct exit_boot_struct {
    struct boot_params *boot_params;
    struct efi_info *efi;
    - struct setup_data *e820ext;
    - __u32 e820ext_size;
    };

    static efi_status_t exit_boot_func(efi_system_table_t *sys_table_arg,
    struct efi_boot_memmap *map,
    void *priv)
    {
    - static bool first = true;
    const char *signature;
    __u32 nr_desc;
    efi_status_t status;
    struct exit_boot_struct *p = priv;

    - if (first) {
    - nr_desc = *map->buff_size / *map->desc_size;
    - if (nr_desc > ARRAY_SIZE(p->boot_params->e820_table)) {
    - u32 nr_e820ext = nr_desc -
    - ARRAY_SIZE(p->boot_params->e820_table);
    -
    - status = alloc_e820ext(nr_e820ext, &p->e820ext,
    - &p->e820ext_size);
    - if (status != EFI_SUCCESS)
    - return status;
    - }
    - first = false;
    - }
    -
    signature = efi_is_64bit() ? EFI64_LOADER_SIGNATURE
    : EFI32_LOADER_SIGNATURE;
    memcpy(&p->efi->efi_loader_signature, signature, sizeof(__u32));
    @@ -687,8 +705,8 @@ static efi_status_t exit_boot(struct boot_params *boot_params, void *handle)
    {
    unsigned long map_sz, key, desc_size, buff_size;
    efi_memory_desc_t *mem_map;
    - struct setup_data *e820ext;
    - __u32 e820ext_size;
    + struct setup_data *e820ext = NULL;
    + __u32 e820ext_size = 0;
    efi_status_t status;
    __u32 desc_version;
    struct efi_boot_memmap map;
    @@ -702,8 +720,10 @@ static efi_status_t exit_boot(struct boot_params *boot_params, void *handle)
    map.buff_size = &buff_size;
    priv.boot_params = boot_params;
    priv.efi = &boot_params->efi_info;
    - priv.e820ext = NULL;
    - priv.e820ext_size = 0;
    +
    + status = allocate_e820(boot_params, &e820ext, &e820ext_size);
    + if (status != EFI_SUCCESS)
    + return status;

    /* Might as well exit boot services now */
    status = efi_exit_boot_services(sys_table, handle, &map, &priv,
    @@ -711,9 +731,6 @@ static efi_status_t exit_boot(struct boot_params *boot_params, void *handle)
    if (status != EFI_SUCCESS)
    return status;

    - e820ext = priv.e820ext;
    - e820ext_size = priv.e820ext_size;
    -
    /* Historic? */
    boot_params->alt_mem_k = 32 * 1024;

    --
    2.19.1
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