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

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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: Jeffrey Hugo <jhugo@codeaurora.org>
Tested-by: Richard Ruigrok <rruigrok@codeaurora.org>
Signed-off-by: Ard 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: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Ard Biesheuvel 2017-04-04 17:02:39 +01:00 committed by Ingo Molnar
parent 138728dd4e
commit 24d7c494ce
2 changed files with 25 additions and 33 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

1
arch/arm64/include/asm/efi.h
View file

@ -1,6 +1,7 @@
#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>

57
drivers/firmware/efi/libstub/fdt.c
View file

@ -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;
@ -262,41 +265,29 @@ 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;
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");
goto fail;
}
/*
* 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.
* Now that we have done our final memory allocation (and free)
* we can get the memory map key needed for exit_boot_services().
*/
new_fdt_size = fdt_size + EFI_PAGE_SIZE;
while (1) {
status = efi_high_alloc(sys_table, new_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");
goto fail;
}
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, new_fdt_size,
cmdline_ptr, initrd_addr, initrd_size);
status = update_fdt(sys_table, (void *)fdt_addr, fdt_size,
(void *)*new_fdt_addr, MAX_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.
*/
efi_free(sys_table, new_fdt_size, *new_fdt_addr);
new_fdt_size += EFI_PAGE_SIZE;
} else {
pr_efi_err(sys_table, "Unable to construct new device tree.\n");
goto fail_free_new_fdt;
}
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;
@ -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);