Commit 70e65afc authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'efi-fixes-for-v6.6-3' of git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi 

Pull EFI fixes from Ard Biesheuvel:
 "The boot_params pointer fix uses a somewhat ugly extern struct
  declaration but this will be cleaned up the next cycle.

   - don't try to print warnings to the console when it is no longer
     available

   - fix theoretical memory leak in SSDT override handling

   - make sure that the boot_params global variable is set before the
     KASLR code attempts to hash it for 'randomness'

   - avoid soft lockups in the memory acceptance code"

* tag 'efi-fixes-for-v6.6-3' of git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi:
  efi/unaccepted: Fix soft lockups caused by parallel memory acceptance
  x86/boot: efistub: Assign global boot_params variable
  efi: fix memory leak in krealloc failure handling
  x86/efistub: Don't try to print after ExitBootService()
parents 1acfd2bd c03d21f0

drivers/firmware/efi/efi.c

+6 −2
Original line number Diff line number Diff line
@@ -273,9 +273,13 @@ static __init int efivar_ssdt_load(void) 
		if (status == EFI_NOT_FOUND) {

			break;

		} else if (status == EFI_BUFFER_TOO_SMALL) {

			name = krealloc(name, name_size, GFP_KERNEL);

			if (!name)

			efi_char16_t *name_tmp =

				krealloc(name, name_size, GFP_KERNEL);

			if (!name_tmp) {

				kfree(name);

				return -ENOMEM;

			}

			name = name_tmp;

			continue;

		}

drivers/firmware/efi/libstub/x86-stub.c

+3 −4
Original line number Diff line number Diff line
@@ -605,11 +605,8 @@ setup_e820(struct boot_params *params, struct setup_data *e820ext, u32 e820ext_s 
			break;



		case EFI_UNACCEPTED_MEMORY:

			if (!IS_ENABLED(CONFIG_UNACCEPTED_MEMORY)) {

				efi_warn_once(

"The system has unaccepted memory,  but kernel does not support it\nConsider enabling CONFIG_UNACCEPTED_MEMORY\n");

			if (!IS_ENABLED(CONFIG_UNACCEPTED_MEMORY))

				continue;

			}

			e820_type = E820_TYPE_RAM;

			process_unaccepted_memory(d->phys_addr,

						  d->phys_addr + PAGE_SIZE * d->num_pages);
@@ -852,6 +849,8 @@ void __noreturn efi_stub_entry(efi_handle_t handle, 
	unsigned long kernel_entry;

	efi_status_t status;



	boot_params_pointer = boot_params;



	efi_system_table = sys_table_arg;

	/* Check if we were booted by the EFI firmware */

	if (efi_system_table->hdr.signature != EFI_SYSTEM_TABLE_SIGNATURE)

drivers/firmware/efi/libstub/x86-stub.h

+2 −0
Original line number Diff line number Diff line
@@ -2,6 +2,8 @@ 


#include <linux/efi.h>



extern struct boot_params *boot_params_pointer asm("boot_params");



extern void trampoline_32bit_src(void *, bool);

extern const u16 trampoline_ljmp_imm_offset;

drivers/firmware/efi/unaccepted_memory.c

+60 −4
Original line number Diff line number Diff line
@@ -5,9 +5,17 @@ 
#include <linux/spinlock.h>

#include <asm/unaccepted_memory.h>



/* Protects unaccepted memory bitmap */

/* Protects unaccepted memory bitmap and accepting_list */

static DEFINE_SPINLOCK(unaccepted_memory_lock);



struct accept_range {

	struct list_head list;

	unsigned long start;

	unsigned long end;

};



static LIST_HEAD(accepting_list);



/*

 * accept_memory() -- Consult bitmap and accept the memory if needed.

 *
@@ -24,6 +32,7 @@ void accept_memory(phys_addr_t start, phys_addr_t end) 
{

	struct efi_unaccepted_memory *unaccepted;

	unsigned long range_start, range_end;

	struct accept_range range, *entry;

	unsigned long flags;

	u64 unit_size;
@@ -78,20 +87,67 @@ void accept_memory(phys_addr_t start, phys_addr_t end) 
	if (end > unaccepted->size * unit_size * BITS_PER_BYTE)

		end = unaccepted->size * unit_size * BITS_PER_BYTE;



	range_start = start / unit_size;



	range.start = start / unit_size;

	range.end = DIV_ROUND_UP(end, unit_size);

retry:

	spin_lock_irqsave(&unaccepted_memory_lock, flags);



	/*

	 * Check if anybody works on accepting the same range of the memory.

	 *

	 * The check is done with unit_size granularity. It is crucial to catch

	 * all accept requests to the same unit_size block, even if they don't

	 * overlap on physical address level.

	 */

	list_for_each_entry(entry, &accepting_list, list) {

		if (entry->end < range.start)

			continue;

		if (entry->start >= range.end)

			continue;



		/*

		 * Somebody else accepting the range. Or at least part of it.

		 *

		 * Drop the lock and retry until it is complete.

		 */

		spin_unlock_irqrestore(&unaccepted_memory_lock, flags);

		goto retry;

	}



	/*

	 * Register that the range is about to be accepted.

	 * Make sure nobody else will accept it.

	 */

	list_add(&range.list, &accepting_list);



	range_start = range.start;

	for_each_set_bitrange_from(range_start, range_end, unaccepted->bitmap,

				   DIV_ROUND_UP(end, unit_size)) {

				   range.end) {

		unsigned long phys_start, phys_end;

		unsigned long len = range_end - range_start;



		phys_start = range_start * unit_size + unaccepted->phys_base;

		phys_end = range_end * unit_size + unaccepted->phys_base;



		/*

		 * Keep interrupts disabled until the accept operation is

		 * complete in order to prevent deadlocks.

		 *

		 * Enabling interrupts before calling arch_accept_memory()

		 * creates an opportunity for an interrupt handler to request

		 * acceptance for the same memory. The handler will continuously

		 * spin with interrupts disabled, preventing other task from

		 * making progress with the acceptance process.

		 */

		spin_unlock(&unaccepted_memory_lock);



		arch_accept_memory(phys_start, phys_end);



		spin_lock(&unaccepted_memory_lock);

		bitmap_clear(unaccepted->bitmap, range_start, len);

	}



	list_del(&range.list);

	spin_unlock_irqrestore(&unaccepted_memory_lock, flags);

}