133 lines
5 KiB
Diff
133 lines
5 KiB
Diff
From 0f09019241a0ea6eee0b9b596a70ec8a66b820ce Mon Sep 17 00:00:00 2001
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From: SolidHal <hal@halemmerich.com>
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Date: Fri, 24 Aug 2018 11:04:43 -0500
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Subject: [PATCH] block: partitions: efi: Add support for IGNOREME GPT
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signature
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This patch adds support for a special GPT header signature marker (using
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the string 'IGNOREME' instead of the spec's 'EFI PART'). This tells the
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kernel to ignore this GPT completely and look at the other one instead.
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Since the kernel always prefers the primary GPT anyway, all we really
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need to do effectively is to check whether the primary GPT is marked
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'IGNOREME' and force evaluation of the secondary one in that case.
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Borrowed from the chrome os 3.14 kernel, the commit can be found here:
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https://chromium.googlesource.com/chromiumos/third_party/kernel/+/abba28d0a1b7361da6e2023352e92687166ca30d
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Also bundled in this commit
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https://chromium.googlesource.com/chromiumos/third_party/kernel/+/bd0c62c7de0c8a63314b7955e5718d8f6192f9d2%5E%21/#F0
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Which is a small compiler warning fix for the above patch
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This patch fixes how the kernel detects and handles certain mmc
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manufatures devices, and allows the partitions on the mmc to be bootable
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and mountable.
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Signed-off-by: SolidHal <hal@halemmerich.com>
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---
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block/partitions/efi.c | 31 ++++++++++++++++++++++---------
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block/partitions/efi.h | 3 ++-
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2 files changed, 24 insertions(+), 10 deletions(-)
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diff --git a/block/partitions/efi.c b/block/partitions/efi.c
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index 39f70d9..aa08380 100644
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--- a/block/partitions/efi.c
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+++ b/block/partitions/efi.c
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@@ -344,23 +344,34 @@ static gpt_header *alloc_read_gpt_header(struct parsed_partitions *state,
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* @lba: logical block address of the GPT header to test
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* @gpt: GPT header ptr, filled on return.
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* @ptes: PTEs ptr, filled on return.
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+ * @ignored is filled on return with 1 if this is an IGNOREME GPT,
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+ * 0 otherwise. May be NULL.
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*
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* Description: returns 1 if valid, 0 on error.
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* If valid, returns pointers to newly allocated GPT header and PTEs.
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*/
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static int is_gpt_valid(struct parsed_partitions *state, u64 lba,
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- gpt_header **gpt, gpt_entry **ptes)
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+ gpt_header **gpt, gpt_entry **ptes, int *ignored)
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{
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u32 crc, origcrc;
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u64 lastlba, pt_size;
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+ if (ignored)
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+ *ignored = 0;
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if (!ptes)
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return 0;
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if (!(*gpt = alloc_read_gpt_header(state, lba)))
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return 0;
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/* Check the GUID Partition Table signature */
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- if (le64_to_cpu((*gpt)->signature) != GPT_HEADER_SIGNATURE) {
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+
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+ if (le64_to_cpu((*gpt)->signature) == GPT_HEADER_SIGNATURE_IGNORED) {
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+ pr_debug("GUID Partition Table at LBA %llu marked IGNOREME\n",
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+ (unsigned long long)lba);
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+ if (ignored)
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+ *ignored = 1;
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+ goto fail;
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+ } else if (le64_to_cpu((*gpt)->signature) != GPT_HEADER_SIGNATURE) {
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pr_debug("GUID Partition Table Header signature is wrong:"
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"%lld != %lld\n",
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(unsigned long long)le64_to_cpu((*gpt)->signature),
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@@ -597,7 +608,7 @@ compare_gpts(gpt_header *pgpt, gpt_header *agpt, u64 lastlba)
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static int find_valid_gpt(struct parsed_partitions *state, gpt_header **gpt,
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gpt_entry **ptes)
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{
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- int good_pgpt = 0, good_agpt = 0, good_pmbr = 0;
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+ int good_pgpt = 0, good_agpt = 0, good_pmbr = 0, pgpt_ignored = 0;
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gpt_header *pgpt = NULL, *agpt = NULL;
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gpt_entry *pptes = NULL, *aptes = NULL;
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legacy_mbr *legacymbr;
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@@ -627,19 +638,20 @@ static int find_valid_gpt(struct parsed_partitions *state, gpt_header **gpt,
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}
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good_pgpt = is_gpt_valid(state, GPT_PRIMARY_PARTITION_TABLE_LBA,
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- &pgpt, &pptes);
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+ &pgpt, &pptes, &pgpt_ignored);
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if (good_pgpt)
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good_agpt = is_gpt_valid(state,
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le64_to_cpu(pgpt->alternate_lba),
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- &agpt, &aptes);
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- if (!good_agpt && force_gpt)
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- good_agpt = is_gpt_valid(state, lastlba, &agpt, &aptes);
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+ &agpt, &aptes, NULL);
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+ if (!good_agpt && (force_gpt || pgpt_ignored))
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+ good_agpt = is_gpt_valid(state, lastlba, &agpt, &aptes, NULL);
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/* The obviously unsuccessful case */
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if (!good_pgpt && !good_agpt)
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goto fail;
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- compare_gpts(pgpt, agpt, lastlba);
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+ if (!pgpt_ignored)
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+ compare_gpts(pgpt, agpt, lastlba);
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/* The good cases */
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if (good_pgpt) {
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@@ -656,7 +668,8 @@ static int find_valid_gpt(struct parsed_partitions *state, gpt_header **gpt,
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*ptes = aptes;
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kfree(pgpt);
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kfree(pptes);
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- pr_warn("Primary GPT is invalid, using alternate GPT.\n");
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+ pr_warn("Primary GPT is %s, using alternate GPT.\n",
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+ pgpt_ignored ? "being ignored" : "invalid");
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return 1;
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}
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diff --git a/block/partitions/efi.h b/block/partitions/efi.h
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index abd0b19..36cddc8 100644
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--- a/block/partitions/efi.h
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+++ b/block/partitions/efi.h
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@@ -41,7 +41,8 @@
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#define GPT_MBR_PROTECTIVE 1
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#define GPT_MBR_HYBRID 2
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-#define GPT_HEADER_SIGNATURE 0x5452415020494645ULL
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+#define GPT_HEADER_SIGNATURE 0x5452415020494645ULL /* 'EFI PART' */
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+#define GPT_HEADER_SIGNATURE_IGNORED 0x454d45524f4e4749ULL /* 'IGNOREME' */
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#define GPT_HEADER_REVISION_V1 0x00010000
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#define GPT_PRIMARY_PARTITION_TABLE_LBA 1
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--
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2.11.0
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