Re: [PATCH v7 16/36] efi: Add an EFI table address match function

[Matt Fleming]

On Fri, 16 Jun, at 01:52:53PM, Tom Lendacky wrote:
> Add a function that will determine if a supplied physical address matches
> the address of an EFI table.
> 
> Reviewed-by: Borislav Petkov 
> Signed-off-by: Tom Lendacky 
> ---
>  drivers/firmware/efi/efi.c |   33 +
>  include/linux/efi.h|7 +++
>  2 files changed, 40 insertions(+)

Reviewed-by: Matt Fleming 
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[PATCH v7 16/36] efi: Add an EFI table address match function

[Tom Lendacky]

Add a function that will determine if a supplied physical address matches
the address of an EFI table.

Reviewed-by: Borislav Petkov 
Signed-off-by: Tom Lendacky 
---
 drivers/firmware/efi/efi.c |   33 +
 include/linux/efi.h|7 +++
 2 files changed, 40 insertions(+)

diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
index b372aad..983675d 100644
--- a/drivers/firmware/efi/efi.c
+++ b/drivers/firmware/efi/efi.c
@@ -55,6 +55,25 @@ struct efi __read_mostly efi = {
 };
 EXPORT_SYMBOL(efi);
 
+static unsigned long *efi_tables[] = {
+   ,
+   ,
+   ,
+   ,
+   ,
+   _systab,
+   _info,
+   ,
+   ,
+   _systab,
+   _vendor,
+   ,
+   _table,
+   ,
+   _table,
+   _attr_table,
+};
+
 static bool disable_runtime;
 static int __init setup_noefi(char *arg)
 {
@@ -854,6 +873,20 @@ int efi_status_to_err(efi_status_t status)
return err;
 }
 
+bool efi_is_table_address(unsigned long phys_addr)
+{
+   unsigned int i;
+
+   if (phys_addr == EFI_INVALID_TABLE_ADDR)
+   return false;
+
+   for (i = 0; i < ARRAY_SIZE(efi_tables); i++)
+   if (*(efi_tables[i]) == phys_addr)
+   return true;
+
+   return false;
+}
+
 #ifdef CONFIG_KEXEC
 static int update_efi_random_seed(struct notifier_block *nb,
  unsigned long code, void *unused)
diff --git a/include/linux/efi.h b/include/linux/efi.h
index 8269bcb..8e24f09 100644
--- a/include/linux/efi.h
+++ b/include/linux/efi.h
@@ -1091,6 +1091,8 @@ static inline bool efi_enabled(int feature)
return test_bit(feature, ) != 0;
 }
 extern void efi_reboot(enum reboot_mode reboot_mode, const char *__unused);
+
+extern bool efi_is_table_address(unsigned long phys_addr);
 #else
 static inline bool efi_enabled(int feature)
 {
@@ -1104,6 +1106,11 @@ static inline bool efi_enabled(int feature)
 {
return false;
 }
+
+static inline bool efi_is_table_address(unsigned long phys_addr)
+{
+   return false;
+}
 #endif
 
 extern int efi_status_to_err(efi_status_t status);

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