From: Jan Beulich <jbeulich@suse.com>
Date: Thu, 15 Oct 2020 10:30:01 +0000 (+0200)
Subject: EFI: further "need_to_free" adjustments
X-Git-Tag: archive/raspbian/4.16.0+51-g0941d6cb-1+rpi1~2^2~42^2~1504
X-Git-Url: https://dgit.raspbian.org/?a=commitdiff_plain;h=a8a85f03c826bea045e345fa405f187049d63584;p=xen.git

EFI: further "need_to_free" adjustments

When processing "chain" directives, the previously loaded config file
gets freed. This needs to be recorded accordingly such that no error
path would try to free the same block of memory a 2nd time.

Furthermore, neither .addr nor .size being zero has any meaning towards
the need to free an allocated chunk anymore. Drop (from read_file()) and
replace (in Arm's efi_arch_use_config_file(), to sensibly retain the
comment) respective assignments.

Fixes: 04be2c3a0678 ("efi/boot.c: add file.need_to_free")
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
---

diff --git a/xen/arch/arm/efi/efi-boot.h b/xen/arch/arm/efi/efi-boot.h
index f64a6604af..cf9c37153f 100644
--- a/xen/arch/arm/efi/efi-boot.h
+++ b/xen/arch/arm/efi/efi-boot.h
@@ -591,7 +591,7 @@ static bool __init efi_arch_use_config_file(EFI_SYSTEM_TABLE *SystemTable)
 
     fdt = lookup_fdt_config_table(SystemTable);
     dtbfile.ptr = fdt;
-    dtbfile.size = 0;  /* Config table memory can't be freed, so set size to 0 */
+    dtbfile.need_to_free = false; /* Config table memory can't be freed. */
     if ( !fdt || fdt_node_offset_by_compatible(fdt, 0, "multiboot,module") < 0 )
     {
         /*
diff --git a/xen/common/efi/boot.c b/xen/common/efi/boot.c
index eb1ef91ba4..63e289ab85 100644
--- a/xen/common/efi/boot.c
+++ b/xen/common/efi/boot.c
@@ -601,10 +601,7 @@ static bool __init read_file(EFI_FILE_HANDLE dir_handle, CHAR16 *name,
                                     PFN_UP(size), &file->addr);
     }
     if ( EFI_ERROR(ret) )
-    {
-        file->addr = 0;
         what = what ?: L"Allocation";
-    }
     else
     {
         file->need_to_free = true;
@@ -1271,8 +1268,11 @@ efi_start(EFI_HANDLE ImageHandle, EFI_SYSTEM_TABLE *SystemTable)
             name.s = get_value(&cfg, "global", "chain");
             if ( !name.s )
                 break;
-            efi_bs->FreePages(cfg.addr, PFN_UP(cfg.size));
-            cfg.addr = 0;
+            if ( cfg.need_to_free )
+            {
+                efi_bs->FreePages(cfg.addr, PFN_UP(cfg.size));
+                cfg.need_to_free = false;
+            }
             if ( !read_file(dir_handle, s2w(&name), &cfg, NULL) )
             {
                 PrintStr(L"Chained configuration file '");