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-rw-r--r--0005-x86-setup-always-reserve-the-first-1M-of-RAM.patch170
1 files changed, 0 insertions, 170 deletions
diff --git a/0005-x86-setup-always-reserve-the-first-1M-of-RAM.patch b/0005-x86-setup-always-reserve-the-first-1M-of-RAM.patch
deleted file mode 100644
index 169ba22ae2d..00000000000
--- a/0005-x86-setup-always-reserve-the-first-1M-of-RAM.patch
+++ /dev/null
@@ -1,170 +0,0 @@
-From 3ffe8ae29143ee20e01b0bc4a63774182b59daf9 Mon Sep 17 00:00:00 2001
-From: Mike Rapoport <rppt@linux.ibm.com>
-Date: Tue, 1 Jun 2021 10:53:52 +0300
-Subject: [PATCH 5/8] x86/setup: always reserve the first 1M of RAM
-
-There are BIOSes that are known to corrupt the memory under 1M, or more
-precisely under 640K because the memory above 640K is anyway reserved for
-the EGA/VGA frame buffer and BIOS.
-
-To prevent usage of the memory that will be potentially clobbered by the
-kernel, the beginning of the memory is always reserved. The exact size of
-the reserved area is determined by CONFIG_X86_RESERVE_LOW build time and
-reservelow command line option. The reserved range may be from 4K to 640K
-with the default of 64K. There are also configurations that reserve the
-entire 1M range, like machines with SandyBridge graphic devices or systems
-that enable crash kernel.
-
-In addition to the potentially clobbered memory, EBDA of unknown size may
-be as low as 128K and the memory above that EBDA start is also reserved
-early.
-
-It would have been possible to reserve the entire range under 1M unless for
-the real mode trampoline that must reside in that area.
-
-To accommodate placement of the real mode trampoline and keep the memory
-safe from being clobbered by BIOS reserve the first 64K of RAM before
-memory allocations are possible and then, after the real mode trampoline is
-allocated, reserve the entire range from 0 to 1M.
-
-Update trim_snb_memory() and reserve_real_mode() to avoid redundant
-reservations of the same memory range.
-
-Also make sure the memory under 1M is not getting freed by
-efi_free_boot_services().
-
-Fixes: a799c2bd29d1 ("x86/setup: Consolidate early memory reservations")
-Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
----
- arch/x86/kernel/setup.c | 35 ++++++++++++++++++++--------------
- arch/x86/platform/efi/quirks.c | 12 ++++++++++++
- arch/x86/realmode/init.c | 14 ++++++++------
- 3 files changed, 41 insertions(+), 20 deletions(-)
-
-diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
-index 7d466f51be1f..d7cfb927864f 100644
---- a/arch/x86/kernel/setup.c
-+++ b/arch/x86/kernel/setup.c
-@@ -638,11 +638,11 @@ static void __init trim_snb_memory(void)
- * them from accessing certain memory ranges, namely anything below
- * 1M and in the pages listed in bad_pages[] above.
- *
-- * To avoid these pages being ever accessed by SNB gfx devices
-- * reserve all memory below the 1 MB mark and bad_pages that have
-- * not already been reserved at boot time.
-+ * To avoid these pages being ever accessed by SNB gfx devices reserve
-+ * bad_pages that have not already been reserved at boot time.
-+ * All memory below the 1 MB mark is anyway reserved later during
-+ * setup_arch(), so there is no need to reserve it here.
- */
-- memblock_reserve(0, 1<<20);
-
- for (i = 0; i < ARRAY_SIZE(bad_pages); i++) {
- if (memblock_reserve(bad_pages[i], PAGE_SIZE))
-@@ -734,14 +734,14 @@ static void __init early_reserve_memory(void)
- * The first 4Kb of memory is a BIOS owned area, but generally it is
- * not listed as such in the E820 table.
- *
-- * Reserve the first memory page and typically some additional
-- * memory (64KiB by default) since some BIOSes are known to corrupt
-- * low memory. See the Kconfig help text for X86_RESERVE_LOW.
-+ * Reserve the first 64K of memory since some BIOSes are known to
-+ * corrupt low memory. After the real mode trampoline is allocated the
-+ * rest of the memory below 640k is reserved.
- *
- * In addition, make sure page 0 is always reserved because on
- * systems with L1TF its contents can be leaked to user processes.
- */
-- memblock_reserve(0, ALIGN(reserve_low, PAGE_SIZE));
-+ memblock_reserve(0, SZ_64K);
-
- early_reserve_initrd();
-
-@@ -752,6 +752,7 @@ static void __init early_reserve_memory(void)
-
- reserve_ibft_region();
- reserve_bios_regions();
-+ trim_snb_memory();
- }
-
- /*
-@@ -1083,14 +1084,20 @@ void __init setup_arch(char **cmdline_p)
- (max_pfn_mapped<<PAGE_SHIFT) - 1);
- #endif
-
-- reserve_real_mode();
--
- /*
-- * Reserving memory causing GPU hangs on Sandy Bridge integrated
-- * graphics devices should be done after we allocated memory under
-- * 1M for the real mode trampoline.
-+ * Find free memory for the real mode trampoline and place it
-+ * there.
-+ * If there is not enough free memory under 1M, on EFI-enabled
-+ * systems there will be additional attempt to reclaim the memory
-+ * for the real mode trampoline at efi_free_boot_services().
-+ *
-+ * Unconditionally reserve the entire first 1M of RAM because
-+ * BIOSes are know to corrupt low memory and several
-+ * hundred kilobytes are not worth complex detection what memory gets
-+ * clobbered. Moreover, on machines with SandyBridge graphics or in
-+ * setups that use crashkernel the entire 1M is anyway reserved.
- */
-- trim_snb_memory();
-+ reserve_real_mode();
-
- init_mem_mapping();
-
-diff --git a/arch/x86/platform/efi/quirks.c b/arch/x86/platform/efi/quirks.c
-index 67d93a243c35..27561b56a821 100644
---- a/arch/x86/platform/efi/quirks.c
-+++ b/arch/x86/platform/efi/quirks.c
-@@ -450,6 +450,18 @@ void __init efi_free_boot_services(void)
- size -= rm_size;
- }
-
-+ /*
-+ * Don't free memory under 1M for two reasons:
-+ * - BIOS might clobber it
-+ * - Crash kernel needs it to be reserved
-+ */
-+ if (start + size < SZ_1M)
-+ continue;
-+ if (start < SZ_1M) {
-+ size -= (SZ_1M - start);
-+ start = SZ_1M;
-+ }
-+
- memblock_free_late(start, size);
- }
-
-diff --git a/arch/x86/realmode/init.c b/arch/x86/realmode/init.c
-index 22fda7d99159..ea42630d4e2e 100644
---- a/arch/x86/realmode/init.c
-+++ b/arch/x86/realmode/init.c
-@@ -29,14 +29,16 @@ void __init reserve_real_mode(void)
-
- /* Has to be under 1M so we can execute real-mode AP code. */
- mem = memblock_find_in_range(0, 1<<20, size, PAGE_SIZE);
-- if (!mem) {
-+ if (!mem)
- pr_info("No sub-1M memory is available for the trampoline\n");
-- return;
-- }
-+ else
-+ set_real_mode_mem(mem);
-
-- memblock_reserve(mem, size);
-- set_real_mode_mem(mem);
-- crash_reserve_low_1M();
-+ /*
-+ * Unconditionally reserve the entire fisrt 1M, see comment in
-+ * setup_arch()
-+ */
-+ memblock_reserve(0, SZ_1M);
- }
-
- static void sme_sev_setup_real_mode(struct trampoline_header *th)
---
-2.32.0
-