[xen staging] EFI: further "need_to_free" adjustments

[patchbot@xxxxxxx]

commit a8a85f03c826bea045e345fa405f187049d63584
Author:     Jan Beulich <jbeulich@xxxxxxxx>
AuthorDate: Thu Oct 15 12:30:01 2020 +0200
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Thu Oct 15 12:30:01 2020 +0200

    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@xxxxxxxx>
    Reviewed-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>
---
 xen/arch/arm/efi/efi-boot.h |  2 +-
 xen/common/efi/boot.c       | 10 +++++-----
 2 files changed, 6 insertions(+), 6 deletions(-)

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 '");
--
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