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Commit 24d7c494 authored by Ard Biesheuvel's avatar Ard Biesheuvel Committed by Ingo Molnar
Browse files

efi/arm-stub: Round up FDT allocation to mapping size 



The FDT is mapped via a fixmap entry that is at least 2 MB in size and
2 MB aligned on 4 KB page size kernels.

On UEFI systems, the FDT allocation may share this 2 MB mapping with a
reserved region (or another memory region that we should never map),
unless we account for this in the size of the allocation (the alignment
is already 2 MB)

So instead of taking guesses at the needed space, simply allocate 2 MB
immediately. The allocation will be recorded as EFI_LOADER_DATA, and the
kernel only memblock_reserve()'s the actual size of the FDT, so the
unused space will be released back to the kernel.

Reviewed-By: default avatarJeffrey Hugo <jhugo@codeaurora.org>
Tested-by: default avatarRichard Ruigrok <rruigrok@codeaurora.org>
Signed-off-by: default avatarArd Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/20170404160245.27812-6-ard.biesheuvel@linaro.org


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 138728dd

arch/arm64/include/asm/efi.h

+1 −0
Original line number Diff line number Diff line 
#ifndef _ASM_EFI_H

#define _ASM_EFI_H



#include <asm/boot.h>

#include <asm/cpufeature.h>

#include <asm/io.h>

#include <asm/mmu_context.h>

drivers/firmware/efi/libstub/fdt.c

+24 −33
Original line number Diff line number Diff line
@@ -206,6 +206,10 @@ static efi_status_t exit_boot_func(efi_system_table_t *sys_table_arg, 
	return update_fdt_memmap(p->new_fdt_addr, map);

}



#ifndef MAX_FDT_SIZE

#define MAX_FDT_SIZE	SZ_2M

#endif



/*

 * Allocate memory for a new FDT, then add EFI, commandline, and

 * initrd related fields to the FDT.  This routine increases the
@@ -233,7 +237,6 @@ efi_status_t allocate_new_fdt_and_exit_boot(efi_system_table_t *sys_table, 
	u32 desc_ver;

	unsigned long mmap_key;

	efi_memory_desc_t *memory_map, *runtime_map;

	unsigned long new_fdt_size;

	efi_status_t status;

	int runtime_entry_count = 0;

	struct efi_boot_memmap map;
@@ -262,42 +265,30 @@ efi_status_t allocate_new_fdt_and_exit_boot(efi_system_table_t *sys_table, 
	       "Exiting boot services and installing virtual address map...\n");



	map.map = &memory_map;

	/*

	 * Estimate size of new FDT, and allocate memory for it. We

	 * will allocate a bigger buffer if this ends up being too

	 * small, so a rough guess is OK here.

	 */

	new_fdt_size = fdt_size + EFI_PAGE_SIZE;

	while (1) {

		status = efi_high_alloc(sys_table, new_fdt_size, EFI_FDT_ALIGN,

	status = efi_high_alloc(sys_table, MAX_FDT_SIZE, EFI_FDT_ALIGN,

				new_fdt_addr, max_addr);

	if (status != EFI_SUCCESS) {

			pr_efi_err(sys_table, "Unable to allocate memory for new device tree.\n");

		pr_efi_err(sys_table,

			   "Unable to allocate memory for new device tree.\n");

		goto fail;

	}



		status = update_fdt(sys_table,

				    (void *)fdt_addr, fdt_size,

				    (void *)*new_fdt_addr, new_fdt_size,

				    cmdline_ptr, initrd_addr, initrd_size);



		/* Succeeding the first time is the expected case. */

		if (status == EFI_SUCCESS)

			break;



		if (status == EFI_BUFFER_TOO_SMALL) {

	/*

			 * We need to allocate more space for the new

			 * device tree, so free existing buffer that is

			 * too small.

	 * Now that we have done our final memory allocation (and free)

	 * we can get the memory map key needed for exit_boot_services().

	 */

			efi_free(sys_table, new_fdt_size, *new_fdt_addr);

			new_fdt_size += EFI_PAGE_SIZE;

		} else {

	status = efi_get_memory_map(sys_table, &map);

	if (status != EFI_SUCCESS)

		goto fail_free_new_fdt;



	status = update_fdt(sys_table, (void *)fdt_addr, fdt_size,

			    (void *)*new_fdt_addr, MAX_FDT_SIZE, cmdline_ptr,

			    initrd_addr, initrd_size);



	if (status != EFI_SUCCESS) {

		pr_efi_err(sys_table, "Unable to construct new device tree.\n");

		goto fail_free_new_fdt;

	}

	}



	priv.runtime_map = runtime_map;

	priv.runtime_entry_count = &runtime_entry_count;
@@ -340,7 +331,7 @@ efi_status_t allocate_new_fdt_and_exit_boot(efi_system_table_t *sys_table, 
	pr_efi_err(sys_table, "Exit boot services failed.\n");



fail_free_new_fdt:

	efi_free(sys_table, new_fdt_size, *new_fdt_addr);

	efi_free(sys_table, MAX_FDT_SIZE, *new_fdt_addr);



fail:

	sys_table->boottime->free_pool(runtime_map);