BACKPORT: efi/arm: Revert "Defer persistent reservations until after …

…paging_init()"

This reverts commit eff896288872d687d9662000ec9ae11b6d61766f, which
deferred the processing of persistent memory reservations to a point
where the memory may have already been allocated and overwritten,
defeating the purpose.

Kernel panic is happened with CentOS 8.0 on the eMAG2 emulator.
The original patchset was pushed to fix the crash on arm64
system with many CPUs. It was already in CentOS 8.0
(https://patchwork.kernel.org/cover/10670151/).
However there's issue with 1 of the patches, and the maintainer
reverted from kernel v5.2.
The patch is required to fix the kernel panic for CentOS 8.0
on the eMAG2 emulator:
[    0.000000] Call trace:
[    0.000000]  efi_apply_persistent_mem_reservations+0xa0/0xc0
[    0.000000]  setup_arch+0x1bc/0x55c
[    0.000000]  start_kernel+0x78/0x4d8
[    0.000000] Code: 8b35d260 6b15003f 110006b5 54fffcad (f9400c01)
[    0.000000] random: get_random_bytes called from print_oops_end_marker+0x30/0x60 with crng_init=0
[    0.000000] ---[ end trace 0000000000000000 ]---
[    0.000000] Kernel panic - not syncing: Fatal exception

This patch is backported from:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?h=v5.2&id=582a32e708823e5957fd73ccd78dc4a9e49d21ea

Signed-off-by: Ard Biesheuvel <[email protected]>
Acked-by: Will Deacon <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Marc Zyngier <[email protected]>
Cc: Mike Rapoport <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: [email protected]
Cc: [email protected]
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
Signed-off-by: Khuong Dinh <[email protected]>

arch/arm64/kernel/setup.c

@@ -313,7 +313,6 @@ void __init setup_arch(char **cmdline_p)
 	arm64_memblock_init();
 
 	paging_init();
-	efi_apply_persistent_mem_reservations();
 
 	acpi_table_upgrade();
 

drivers/firmware/efi/efi.c

@@ -598,11 +598,7 @@ 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;
 

drivers/firmware/efi/libstub/arm-stub.c

@@ -100,9 +100,6 @@ 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) {

include/linux/efi.h

@@ -1200,8 +1200,6 @@ extern void efi_reboot(enum reboot_mode reboot_mode, const char *__unused);
 
 extern bool efi_is_table_address(unsigned long phys_addr);
 extern void __init efi_set_secure_boot(enum efi_secureboot_mode mode);
-
-extern int efi_apply_persistent_mem_reservations(void);
 #else
 static inline bool efi_enabled(int feature)
 {
@@ -1221,10 +1219,6 @@ static inline bool efi_is_table_address(unsigned long phys_addr)
 	return false;
 }
 
-static inline int efi_apply_persistent_mem_reservations(void)
-{
-	return 0;
-}
 static inline void efi_set_secure_boot(enum efi_secureboot_mode mode) {}
 #endif