x86/efi: Allocate e820 buffer before calling efi_exit_boot_service

BugLink: https://bugs.launchpad.net/bugs/1837161
commit b84a64fad40637b1c9fa4f4dbf847a23e29e672b upstream.

The following 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() ensured 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.

 [ mingo: minor cleanliness edits. ]

Signed-off-by: Eric Snowberg <eric.snowberg@oracle.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: <stable@vger.kernel.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arend van Spriel <arend.vanspriel@broadcom.com>
Cc: Bhupesh Sharma <bhsharma@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Hans de Goede <hdegoede@redhat.com>
Cc: Joe Perches <joe@perches.com>
Cc: Jon Hunter <jonathanh@nvidia.com>
Cc: Julien Thierry <julien.thierry@arm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Nathan Chancellor <natechancellor@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sai Praneeth Prakhya <sai.praneeth.prakhya@intel.com>
Cc: Sedat Dilek <sedat.dilek@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: YiFei Zhu <zhuyifei1999@gmail.com>
Cc: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/20181129171230.18699-2-ard.biesheuvel@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Connor Kuehl <connor.kuehl@canonical.com>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>

diff --git a/arch/x86/boot/compressed/eboot.c b/arch/x86/boot/compressed/eboot.c
index 49914cdfb5d5387c4f3a28edea2d320460abc1d3..0beb039d98af1dbcde7d5c38432483c6857d7edd 100644 (file)
--- 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
@@ -869,11 +870,43 @@ 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            = ↦
+       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;
        bool is64;
 };
 
@@ -881,26 +914,11 @@ 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 = p->is64 ? EFI64_LOADER_SIGNATURE : EFI32_LOADER_SIGNATURE;
        memcpy(&p->efi->efi_loader_signature, signature, sizeof(__u32));
 
@@ -923,8 +941,8 @@ static efi_status_t exit_boot(struct boot_params *boot_params,
 {
        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;
@@ -938,18 +956,18 @@ static efi_status_t exit_boot(struct boot_params *boot_params,
        map.buff_size =         &buff_size;
        priv.boot_params =      boot_params;
        priv.efi =              &boot_params->efi_info;
-       priv.e820ext =          NULL;
-       priv.e820ext_size =     0;
        priv.is64 =             is64;
 
+       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,
                                        exit_boot_func);
        if (status != EFI_SUCCESS)
                return status;
 
-       e820ext = priv.e820ext;
-       e820ext_size = priv.e820ext_size;
        /* Historic? */
        boot_params->alt_mem_k = 32 * 1024;