From b724e714d3604b107c01603591390b8416633a26 Mon Sep 17 00:00:00 2001
From: Jeremy Soller <jackpot51@gmail.com>
Date: Wed, 21 Sep 2022 14:42:45 -0600
Subject: [PATCH] Move EFI partition to second megabyte
---
src/lib.rs | 46 ++++++++++++++++++++++++----------------------
1 file changed, 24 insertions(+), 22 deletions(-)
diff --git a/src/lib.rs b/src/lib.rs
index c071e9a..bbdfcd6 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -408,19 +408,19 @@ pub fn with_whole_disk<P, F, T>(disk_path: P, bootloader_bios: &[u8], bootloader
// Calculate partition offsets
let gpt_reserved = 34 * 512; // GPT always reserves 34 512-byte sectors
+ let mibi = 1024 * 1024;
// First megabyte of the disk is reserved for BIOS partition, wich includes GPT tables
- let bios_size = 1024 * 1024;
let bios_start = gpt_reserved / block_size;
- let bios_end = (bios_size / block_size) - 1; // End at 1 MiB
+ let bios_end = (mibi / block_size) - 1;
- // Last megabyte of the disk is reserved for EFI partition
- let efi_size = 1024 * 1024;
- let efi_end = ((disk_size - gpt_reserved) / block_size) - 1;
- let efi_start = (disk_size - efi_size) / block_size; // 1 MiB from end of disk
+ // Second megabyte of the disk is reserved for EFI partition
+ let efi_start = bios_end + 1;
+ let efi_end = efi_start + (mibi / block_size) - 1;
- let redoxfs_start = bios_end + 1;
- let redoxfs_end = efi_start - 1;
+ // The rest of the disk is RedoxFS, reserving the GPT table mirror at the end of disk
+ let redoxfs_start = efi_end + 1;
+ let redoxfs_end = ((((disk_size - gpt_reserved) / mibi) * mibi) / block_size) - 1;
// Format and install BIOS partition
{
@@ -455,6 +455,17 @@ pub fn with_whole_disk<P, F, T>(disk_path: P, bootloader_bios: &[u8], bootloader
});
partition_id += 1;
+ // Add EFI boot partition
+ partitions.insert(partition_id, gpt::partition::Partition {
+ part_type_guid: gpt::partition_types::EFI,
+ part_guid: uuid::Uuid::new_v4(),
+ first_lba: efi_start,
+ last_lba: efi_end,
+ flags: 0, // TODO
+ name: "EFI".to_string(),
+ });
+ partition_id += 1;
+
// Add RedoxFS partition
partitions.insert(partition_id, gpt::partition::Partition {
//TODO: Use REDOX_REDOXFS type (needs GPT crate changes)
@@ -465,17 +476,6 @@ pub fn with_whole_disk<P, F, T>(disk_path: P, bootloader_bios: &[u8], bootloader
flags: 0,
name: "REDOX".to_string(),
});
- partition_id += 1;
-
- // Add EFI boot partition
- partitions.insert(partition_id, gpt::partition::Partition {
- part_type_guid: gpt::partition_types::EFI,
- part_guid: uuid::Uuid::new_v4(),
- first_lba: efi_start,
- last_lba: efi_end,
- flags: 0, // TODO
- name: "EFI".to_string(),
- });
eprintln!("Writing GPT tables: {:#?}", partitions);
@@ -488,13 +488,15 @@ pub fn with_whole_disk<P, F, T>(disk_path: P, bootloader_bios: &[u8], bootloader
// Format and install EFI partition
{
+ let disk_efi_start = efi_start * block_size;
+ let disk_efi_end = (efi_end + 1) * block_size;
let mut disk_efi = fscommon::StreamSlice::new(
&mut disk_file,
- efi_start * block_size,
- (efi_end + 1) * block_size,
+ disk_efi_start,
+ disk_efi_end,
)?;
- eprintln!("Formatting EFI partition with size {:#x}", efi_size);
+ eprintln!("Formatting EFI partition with size {:#x}", disk_efi_end - disk_efi_start);
fatfs::format_volume(&mut disk_efi, fatfs::FormatVolumeOptions::new())?;
eprintln!("Opening EFI partition");
--
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