[Xen-devel] [PATCH for-4.6] efi: introduce efi_arch_flush_dcache_area

[Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>]

Objects loaded by FileHandle->Read need to be flushed to dcache,
otherwise copy_from_paddr will read stale data when copying the kernel,
causing a failure to boot.

Introduce efi_arch_flush_dcache_area and call it from read_file.

This commit introduces no functional changes on x86.

Reported-by: Mark Rutland <mark.rutland@xxxxxxx>
Signed-off-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
CC: ian.campbell@xxxxxxxxxx
CC: JBeulich@xxxxxxxx
CC: wei.liu2@xxxxxxxxxx
---
 xen/arch/arm/efi/efi-boot.h |    7 +++++++
 xen/arch/x86/efi/efi-boot.h |    2 ++
 xen/common/efi/boot.c       |    3 ++-
 3 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/xen/arch/arm/efi/efi-boot.h b/xen/arch/arm/efi/efi-boot.h
index 6a12d91..fd79658 100644
--- a/xen/arch/arm/efi/efi-boot.h
+++ b/xen/arch/arm/efi/efi-boot.h
@@ -9,6 +9,7 @@
 #include <asm/smp.h>
 
 void noreturn efi_xen_start(void *fdt_ptr, uint32_t fdt_size);
+void __flush_dcache_area(const void * vaddr, unsigned long size);
 
 #define DEVICE_TREE_GUID \
 {0xb1b621d5, 0xf19c, 0x41a5, {0x83, 0x0b, 0xd9, 0x15, 0x2c, 0x69, 0xaa, 0xe0}}
@@ -571,6 +572,12 @@ static void __init 
efi_arch_video_init(EFI_GRAPHICS_OUTPUT_PROTOCOL *gop,
                                        EFI_GRAPHICS_OUTPUT_MODE_INFORMATION 
*mode_info)
 {
 }
+
+static void efi_arch_flush_dcache_area(const void *vaddr, UINTN size)
+{
+    __flush_dcache_area(vaddr, size);
+}
+
 /*
  * Local variables:
  * mode: C
diff --git a/xen/arch/x86/efi/efi-boot.h b/xen/arch/x86/efi/efi-boot.h
index 2dd69f6..4c7f383 100644
--- a/xen/arch/x86/efi/efi-boot.h
+++ b/xen/arch/x86/efi/efi-boot.h
@@ -640,6 +640,8 @@ static bool_t __init 
efi_arch_use_config_file(EFI_SYSTEM_TABLE *SystemTable)
     return 1; /* x86 always uses a config file */
 }
 
+static void efi_arch_flush_dcache_area(const void *vaddr, UINTN size) { }
+
 /*
  * Local variables:
  * mode: C
diff --git a/xen/common/efi/boot.c b/xen/common/efi/boot.c
index 75a939f..f0f26c1 100644
--- a/xen/common/efi/boot.c
+++ b/xen/common/efi/boot.c
@@ -526,7 +526,8 @@ static bool_t __init read_file(EFI_FILE_HANDLE dir_handle, 
CHAR16 *name,
         PrintErr(what);
         PrintErr(L" failed for ");
         PrintErrMesg(name, ret);
-    }
+    } else
+        efi_arch_flush_dcache_area(file->ptr, file->size);
 
     return 1;
 }
-- 
1.7.10.4


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