@@ -16,6 +16,7 @@ typedef guid_t efi_guid_t __aligned(__alignof__(u32));
#define ACPI_TABLE_GUID EFI_GUID(0xeb9d2d30, 0x2d88, 0x11d3, 0x9a, 0x16, 0x00, 0x90, 0x27, 0x3f, 0xc1, 0x4d)
#define ACPI_20_TABLE_GUID EFI_GUID(0x8868e871, 0xe4f1, 0x11d3, 0xbc, 0x22, 0x00, 0x80, 0xc7, 0x3c, 0x88, 0x81)
#define EFI_CC_BLOB_GUID EFI_GUID(0x067b1f5f, 0xcf26, 0x44c5, 0x85, 0x54, 0x93, 0xd7, 0x77, 0x91, 0x2d, 0x42)
+#define LINUX_EFI_UNACCEPTED_MEM_TABLE_GUID EFI_GUID(0xd5d1de3c, 0x105c, 0x44f9, 0x9e, 0xa9, 0xbc, 0xef, 0x98, 0x12, 0x00, 0x31)
#define EFI32_LOADER_SIGNATURE "EL32"
#define EFI64_LOADER_SIGNATURE "EL64"
@@ -32,6 +33,7 @@ typedef struct {
} efi_table_hdr_t;
#define EFI_CONVENTIONAL_MEMORY 7
+#define EFI_UNACCEPTED_MEMORY 15
#define EFI_MEMORY_MORE_RELIABLE \
((u64)0x0000000000010000ULL) /* higher reliability */
@@ -104,6 +106,14 @@ struct efi_setup_data {
u64 reserved[8];
};
+struct efi_unaccepted_memory {
+ u32 version;
+ u32 unit_size;
+ u64 phys_base;
+ u64 size;
+ unsigned long bitmap[];
+};
+
static inline int efi_guidcmp (efi_guid_t left, efi_guid_t right)
{
return memcmp(&left, &right, sizeof (efi_guid_t));
@@ -672,6 +672,33 @@ static bool process_mem_region(struct mem_vector *region,
}
#ifdef CONFIG_EFI
+
+/*
+ * Only EFI_CONVENTIONAL_MEMORY and EFI_UNACCEPTED_MEMORY (if supported) are
+ * guaranteed to be free.
+ *
+ * Pick free memory more conservatively than the EFI spec allows: according to
+ * the spec, EFI_BOOT_SERVICES_{CODE|DATA} are also free memory and thus
+ * available to place the kernel image into, but in practice there's firmware
+ * where using that memory leads to crashes. Buggy vendor EFI code registers
+ * for an event that triggers on SetVirtualAddressMap(). The handler assumes
+ * that EFI_BOOT_SERVICES_DATA memory has not been touched by loader yet, which
+ * is probably true for Windows.
+ *
+ * Preserve EFI_BOOT_SERVICES_* regions until after SetVirtualAddressMap().
+ */
+static inline bool memory_type_is_free(efi_memory_desc_t *md)
+{
+ if (md->type == EFI_CONVENTIONAL_MEMORY)
+ return true;
+
+ if (IS_ENABLED(CONFIG_UNACCEPTED_MEMORY) &&
+ md->type == EFI_UNACCEPTED_MEMORY)
+ return true;
+
+ return false;
+}
+
/*
* Returns true if we processed the EFI memmap, which we prefer over the E820
* table if it is available.
@@ -716,18 +743,7 @@ process_efi_entries(unsigned long minimum, unsigned long image_size)
for (i = 0; i < nr_desc; i++) {
md = efi_early_memdesc_ptr(pmap, e->efi_memdesc_size, i);
- /*
- * Here we are more conservative in picking free memory than
- * the EFI spec allows:
- *
- * According to the spec, EFI_BOOT_SERVICES_{CODE|DATA} are also
- * free memory and thus available to place the kernel image into,
- * but in practice there's firmware where using that memory leads
- * to crashes.
- *
- * Only EFI_CONVENTIONAL_MEMORY is guaranteed to be free.
- */
- if (md->type != EFI_CONVENTIONAL_MEMORY)
+ if (!memory_type_is_free(md))
continue;
if (efi_soft_reserve_enabled() &&
@@ -1,9 +1,50 @@
// SPDX-License-Identifier: GPL-2.0-only
#include "error.h"
+#include "misc.h"
void arch_accept_memory(phys_addr_t start, phys_addr_t end)
{
/* Platform-specific memory-acceptance call goes here */
error("Cannot accept memory");
}
+
+bool init_unaccepted_memory(void)
+{
+ guid_t guid = LINUX_EFI_UNACCEPTED_MEM_TABLE_GUID;
+ struct efi_unaccepted_memory *table;
+ unsigned long cfg_table_pa;
+ unsigned int cfg_table_len;
+ enum efi_type et;
+ int ret;
+
+ et = efi_get_type(boot_params);
+ if (et == EFI_TYPE_NONE)
+ return false;
+
+ ret = efi_get_conf_table(boot_params, &cfg_table_pa, &cfg_table_len);
+ if (ret) {
+ warn("EFI config table not found.");
+ return false;
+ }
+
+ table = (void *)efi_find_vendor_table(boot_params, cfg_table_pa,
+ cfg_table_len, guid);
+ if (!table)
+ return false;
+
+ if (table->version != 1)
+ error("Unknown version of unaccepted memory table\n");
+
+ /*
+ * In many cases unaccepted_table is already set by EFI stub, but it
+ * has to be initialized again to cover cases when the table is not
+ * allocated by EFI stub or EFI stub copied the kernel image with
+ * efi_relocate_kernel() before the variable is set.
+ *
+ * It must be initialized before the first usage of accept_memory().
+ */
+ unaccepted_table = table;
+
+ return true;
+}
@@ -455,6 +455,12 @@ asmlinkage __visible void *extract_kernel(void *rmode, memptr heap,
#endif
debug_putstr("\nDecompressing Linux... ");
+
+ if (init_unaccepted_memory()) {
+ debug_putstr("Accepting memory... ");
+ accept_memory(__pa(output), __pa(output) + needed_size);
+ }
+
__decompress(input_data, input_len, NULL, NULL, output, output_len,
NULL, error);
entry_offset = parse_elf(output);
@@ -247,4 +247,14 @@ static inline unsigned long efi_find_vendor_table(struct boot_params *bp,
}
#endif /* CONFIG_EFI */
+#ifdef CONFIG_UNACCEPTED_MEMORY
+bool init_unaccepted_memory(void);
+#else
+static inline bool init_unaccepted_memory(void) { return false; }
+#endif
+
+/* Defined in EFI stub */
+extern struct efi_unaccepted_memory *unaccepted_table;
+void accept_memory(phys_addr_t start, phys_addr_t end);
+
#endif /* BOOT_COMPRESSED_MISC_H */