@@ -1168,7 +1168,8 @@
Format: {"off" | "on" | "skip[mbr]"}
efi= [EFI]
- Format: { "old_map", "nochunk", "noruntime", "debug" }
+ Format: { "old_map", "nochunk", "noruntime", "debug",
+ "nosoftreserve" }
old_map [X86-64]: switch to the old ioremap-based EFI
runtime services mapping. 32-bit still uses this one by
default.
@@ -1177,6 +1178,12 @@
firmware implementations.
noruntime : disable EFI runtime services support
debug: enable misc debug output
+ nosoftreserve: The EFI_MEMORY_SP (Specific Purpose)
+ attribute may cause the kernel to reserve the
+ memory range for a memory mapping driver to
+ claim. Specify efi=nosoftreserve to disable this
+ reservation and treat the memory by its base type
+ (i.e. EFI_CONVENTIONAL_MEMORY / "System RAM").
efi_no_storage_paranoia [EFI; X86]
Using this parameter you can use more than 50% of
@@ -75,6 +75,27 @@ config EFI_MAX_FAKE_MEM
Ranges can be set up to this value using comma-separated list.
The default value is 8.
+config EFI_SOFT_RESERVE
+ bool "Reserve EFI Specific Purpose Memory"
+ depends on EFI && EFI_STUB && ACPI_HMAT
+ default ACPI_HMAT
+ help
+ On systems that have mixed performance classes of memory EFI
+ may indicate specific purpose memory with an attribute (See
+ EFI_MEMORY_SP in UEFI 2.8). A memory range tagged with this
+ attribute may have unique performance characteristics compared
+ to the system's general purpose "System RAM" pool. On the
+ expectation that such memory has application specific usage,
+ and its base EFI memory type is "conventional" answer Y to
+ arrange for the kernel to reserve it as a "Soft Reserved"
+ resource, and set aside for direct-access (device-dax) by
+ default. The memory range can later be optionally assigned to
+ the page allocator by system administrator policy via the
+ device-dax kmem facility. Say N to have the kernel treat this
+ memory as "System RAM" by default.
+
+ If unsure, say Y.
+
config EFI_PARAMS_FROM_FDT
bool
help
@@ -81,6 +81,11 @@ bool efi_runtime_disabled(void)
return disable_runtime;
}
+bool __pure __efi_soft_reserve_enabled(void)
+{
+ return !efi_enabled(EFI_MEM_NO_SOFT_RESERVE);
+}
+
static int __init parse_efi_cmdline(char *str)
{
if (!str) {
@@ -94,6 +99,9 @@ static int __init parse_efi_cmdline(char *str)
if (parse_option_str(str, "noruntime"))
disable_runtime = true;
+ if (parse_option_str(str, "nosoftreserve"))
+ set_bit(EFI_MEM_NO_SOFT_RESERVE, &efi.flags);
+
return 0;
}
early_param("efi", parse_efi_cmdline);
@@ -32,6 +32,7 @@ static unsigned long __chunk_size = EFI_READ_CHUNK_SIZE;
static int __section(.data) __nokaslr;
static int __section(.data) __quiet;
static int __section(.data) __novamap;
+static bool __section(.data) efi_nosoftreserve;
int __pure nokaslr(void)
{
@@ -45,6 +46,10 @@ int __pure novamap(void)
{
return __novamap;
}
+bool __pure __efi_soft_reserve_enabled(void)
+{
+ return !efi_nosoftreserve;
+}
#define EFI_MMAP_NR_SLACK_SLOTS 8
@@ -211,6 +216,10 @@ efi_status_t efi_high_alloc(efi_system_table_t *sys_table_arg,
if (desc->type != EFI_CONVENTIONAL_MEMORY)
continue;
+ if (efi_soft_reserve_enabled() &&
+ (desc->attribute & EFI_MEMORY_SP))
+ continue;
+
if (desc->num_pages < nr_pages)
continue;
@@ -305,6 +314,10 @@ efi_status_t efi_low_alloc_above(efi_system_table_t *sys_table_arg,
if (desc->type != EFI_CONVENTIONAL_MEMORY)
continue;
+ if (efi_soft_reserve_enabled() &&
+ (desc->attribute & EFI_MEMORY_SP))
+ continue;
+
if (desc->num_pages < nr_pages)
continue;
@@ -484,6 +497,12 @@ efi_status_t efi_parse_options(char const *cmdline)
__novamap = 1;
}
+ if (IS_ENABLED(CONFIG_EFI_SOFT_RESERVE) &&
+ !strncmp(str, "nosoftreserve", 7)) {
+ str += strlen("nosoftreserve");
+ efi_nosoftreserve = 1;
+ }
+
/* Group words together, delimited by "," */
while (*str && *str != ' ' && *str != ',')
str++;
@@ -1202,6 +1202,7 @@ extern int __init efi_setup_pcdp_console(char *);
#define EFI_DBG 8 /* Print additional debug info at runtime */
#define EFI_NX_PE_DATA 9 /* Can runtime data regions be mapped non-executable? */
#define EFI_MEM_ATTR 10 /* Did firmware publish an EFI_MEMORY_ATTRIBUTES table? */
+#define EFI_MEM_NO_SOFT_RESERVE 11 /* Is the kernel configured to ignore soft reservations? */
#ifdef CONFIG_EFI
/*
@@ -1212,6 +1213,14 @@ static inline bool efi_enabled(int feature)
return test_bit(feature, &efi.flags) != 0;
}
extern void efi_reboot(enum reboot_mode reboot_mode, const char *__unused);
+
+bool __pure __efi_soft_reserve_enabled(void);
+
+static inline bool __pure efi_soft_reserve_enabled(void)
+{
+ return IS_ENABLED(CONFIG_EFI_SOFT_RESERVE)
+ && __efi_soft_reserve_enabled();
+}
#else
static inline bool efi_enabled(int feature)
{
@@ -1225,6 +1234,11 @@ efi_capsule_pending(int *reset_type)
{
return false;
}
+
+static inline bool efi_soft_reserve_enabled(void)
+{
+ return false;
+}
#endif
extern int efi_status_to_err(efi_status_t status);