efi/arm: Defer persistent reservations until after paging_init()

Ard Biesheuvel · Ingo Molnar · commit eff896288872 · 2018-11-15T10:04:46.000+01:00
The new memory EFI reservation feature we introduced to allow memory reservations to persist across kexec may trigger an unbounded number of calls to memblock_reserve(). The memblock subsystem can deal with this fine, but not before memblock resizing is enabled, which we can only do after paging_init(), when the memory we reallocate the array into is actually mapped. So break out the memreserve table processing into a separate routine and call it after paging_init() on arm64. On ARM, because of limited reviewing bandwidth of the maintainer, we cannot currently fix this, so instead, disable the EFI persistent memreserve entirely on ARM so we can fix it later. Tested-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-efi@vger.kernel.org Link: http://lkml.kernel.org/r/20181114175544.12860-5-ard.biesheuvel@linaro.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c
@@ -313,6 +313,7 @@ void __init setup_arch(char **cmdline_p)
 	arm64_memblock_init();
 
 	paging_init();
+	efi_apply_persistent_mem_reservations();
 
 	acpi_table_upgrade();
 
diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
@@ -592,7 +592,11 @@ int __init efi_config_parse_tables(void *config_tables, int count, int sz,
 
 		early_memunmap(tbl, sizeof(*tbl));
 	}
+	return 0;
+}
 
+int __init efi_apply_persistent_mem_reservations(void)
+{
 	if (efi.mem_reserve != EFI_INVALID_TABLE_ADDR) {
 		unsigned long prsv = efi.mem_reserve;
 
diff --git a/drivers/firmware/efi/libstub/arm-stub.c b/drivers/firmware/efi/libstub/arm-stub.c
@@ -75,6 +75,9 @@ void install_memreserve_table(efi_system_table_t *sys_table_arg)
 	efi_guid_t memreserve_table_guid = LINUX_EFI_MEMRESERVE_TABLE_GUID;
 	efi_status_t status;
 
+	if (IS_ENABLED(CONFIG_ARM))
+		return;
+
 	status = efi_call_early(allocate_pool, EFI_LOADER_DATA, sizeof(*rsv),
 				(void **)&rsv);
 	if (status != EFI_SUCCESS) {
diff --git a/include/linux/efi.h b/include/linux/efi.h
@@ -1167,6 +1167,8 @@ static inline bool efi_enabled(int feature)
 extern void efi_reboot(enum reboot_mode reboot_mode, const char *__unused);
 
 extern bool efi_is_table_address(unsigned long phys_addr);
+
+extern int efi_apply_persistent_mem_reservations(void);
 #else
 static inline bool efi_enabled(int feature)
 {
@@ -1185,6 +1187,11 @@ static inline bool efi_is_table_address(unsigned long phys_addr)
 {
 	return false;
 }
+
+static inline int efi_apply_persistent_mem_reservations(void)
+{
+	return 0;
+}
 #endif
 
 extern int efi_status_to_err(efi_status_t status);

Original file line number	Diff line number	Diff line change
`@@ -592,7 +592,11 @@ int __init efi_config_parse_tables(void *config_tables, int count, int sz,`
`592`	`592`
`593`	`593`	`early_memunmap(tbl, sizeof(*tbl));`
`594`	`594`	`}`
	`595`	`+ return 0;`
	`596`	`+}`
`595`	`597`
	`598`	`+int __init efi_apply_persistent_mem_reservations(void)`
	`599`	`+{`
`596`	`600`	`if (efi.mem_reserve != EFI_INVALID_TABLE_ADDR) {`
`597`	`601`	`unsigned long prsv = efi.mem_reserve;`
`598`	`602`
Original file line number	Diff line number	Diff line change
`@@ -1167,6 +1167,8 @@ static inline bool efi_enabled(int feature)`
`1167`	`1167`	`extern void efi_reboot(enum reboot_mode reboot_mode, const char *__unused);`
`1168`	`1168`
`1169`	`1169`	`extern bool efi_is_table_address(unsigned long phys_addr);`
	`1170`	`+`
	`1171`	`+extern int efi_apply_persistent_mem_reservations(void);`
`1170`	`1172`	`#else`
`1171`	`1173`	`static inline bool efi_enabled(int feature)`
`1172`	`1174`	`{`
`@@ -1185,6 +1187,11 @@ static inline bool efi_is_table_address(unsigned long phys_addr)`
`1185`	`1187`	`{`
`1186`	`1188`	`return false;`
`1187`	`1189`	`}`
	`1190`	`+`
	`1191`	`+static inline int efi_apply_persistent_mem_reservations(void)`
	`1192`	`+{`
	`1193`	`+ return 0;`
	`1194`	`+}`
`1188`	`1195`	`#endif`
`1189`	`1196`
`1190`	`1197`	`extern int efi_status_to_err(efi_status_t status);`