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Subject[PATCH 08/18] Generalize relocate_kernel() for use by other architectures.
Date
Rename relocate_kernel() to efi_relocate_kernel(), and take
parameters rather than x86 specific structure. Add max_addr
argument as for ARM we have some address constraints that we
need to enforce when relocating the kernel. Add alloc_size
parameter for use by ARM64 which uses an uncompressed kernel,
and needs to allocate space for BSS.

Signed-off-by: Roy Franz <roy.franz@linaro.org>
---
arch/x86/boot/compressed/eboot.c | 10 ++++-
drivers/firmware/efi/efi-stub-helper.c | 72 ++++++++++++++++++++++----------
2 files changed, 59 insertions(+), 23 deletions(-)

diff --git a/arch/x86/boot/compressed/eboot.c b/arch/x86/boot/compressed/eboot.c
index 5bbba86..2e997b6 100644
--- a/arch/x86/boot/compressed/eboot.c
+++ b/arch/x86/boot/compressed/eboot.c
@@ -733,10 +733,16 @@ struct boot_params *efi_main(void *handle, efi_system_table_t *_table,
* address, relocate it.
*/
if (hdr->pref_address != hdr->code32_start) {
- status = relocate_kernel(hdr);
-
+ unsigned long bzimage_addr = hdr->code32_start;
+ status = efi_relocate_kernel(sys_table, &bzimage_addr,
+ hdr->init_size, hdr->init_size,
+ hdr->pref_address,
+ hdr->kernel_alignment);
if (status != EFI_SUCCESS)
goto fail;
+
+ hdr->pref_address = hdr->code32_start;
+ hdr->code32_start = bzimage_addr;
}

status = exit_boot(boot_params, handle);
diff --git a/drivers/firmware/efi/efi-stub-helper.c b/drivers/firmware/efi/efi-stub-helper.c
index 1d5f219..9a92129 100644
--- a/drivers/firmware/efi/efi-stub-helper.c
+++ b/drivers/firmware/efi/efi-stub-helper.c
@@ -483,38 +483,68 @@ fail:

return status;
}
-
-static efi_status_t relocate_kernel(struct setup_header *hdr)
+/* Relocate a kernel image, either compressed or uncompressed.
+ * In the ARM64 case, all kernel images are currently
+ * uncompressed, and as such when we relocate it we need to
+ * allocate additional space for the BSS segment. Any low
+ * memory that this function should avoid needs to be
+ * unavailable in the EFI memory map, as if the preferred
+ * address is not available the lowest available address will
+ * be used.
+ */
+static efi_status_t efi_relocate_kernel(efi_system_table_t *sys_table_arg,
+ unsigned long *image_addr,
+ unsigned long image_size,
+ unsigned long alloc_size,
+ unsigned long preferred_addr,
+ unsigned long alignment)
{
- unsigned long start, nr_pages;
+ unsigned long cur_image_addr;
+ unsigned long new_addr = 0;
efi_status_t status;
+ unsigned long nr_pages;
+ efi_physical_addr_t efi_addr = preferred_addr;
+
+ if (!image_addr || !image_size || !alloc_size)
+ return EFI_INVALID_PARAMETER;
+ if (alloc_size < image_size)
+ return EFI_INVALID_PARAMETER;
+
+ cur_image_addr = *image_addr;

/*
* The EFI firmware loader could have placed the kernel image
- * anywhere in memory, but the kernel has various restrictions
- * on the max physical address it can run at. Attempt to move
- * the kernel to boot_params.pref_address, or as low as
- * possible.
+ * anywhere in memory, but the kernel has restrictions on the
+ * max physical address it can run at. Some architectures
+ * also have a prefered address, so first try to relocate
+ * to the preferred address. If that fails, allocate as low
+ * as possible while respecting the required alignment.
*/
- start = hdr->pref_address;
- nr_pages = round_up(hdr->init_size, EFI_PAGE_SIZE) / EFI_PAGE_SIZE;
-
- status = efi_call_phys4(sys_table->boottime->allocate_pages,
+ nr_pages = round_up(alloc_size, EFI_PAGE_SIZE) / EFI_PAGE_SIZE;
+ status = efi_call_phys4(sys_table_arg->boottime->allocate_pages,
EFI_ALLOCATE_ADDRESS, EFI_LOADER_DATA,
- nr_pages, &start);
+ nr_pages, &efi_addr);
+ new_addr = efi_addr;
+ /* If preferred address allocation failed allocate as low as
+ * possible. */
+ if (status != EFI_SUCCESS) {
+ status = efi_low_alloc(sys_table_arg, alloc_size, alignment,
+ &new_addr);
+ }
if (status != EFI_SUCCESS) {
- status = efi_low_alloc(sys_table, hdr->init_size,
- hdr->kernel_alignment, &start);
- if (status != EFI_SUCCESS)
- efi_printk(sys_table, "Failed to alloc mem for kernel\n");
+ efi_printk(sys_table_arg, "ERROR: Failed to allocate usable memory for kernel.\n");
+ return status;
}

- if (status == EFI_SUCCESS)
- memcpy((void *)start, (void *)(unsigned long)hdr->code32_start,
- hdr->init_size);
+ /* We know source/dest won't overlap since both memory ranges
+ * have been allocated by UEFI, so we can safely use memcpy.
+ */
+ memcpy((void *)new_addr, (void *)cur_image_addr, image_size);
+ /* Zero any extra space we may have allocated for BSS. */
+ memset((void *)(new_addr + image_size), alloc_size - image_size, 0);

- hdr->pref_address = hdr->code32_start;
- hdr->code32_start = (__u32)start;
+ /* Return the new address of the relocated image. */
+ *image_addr = new_addr;

return status;
}
--
1.7.10.4


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