[PATCH 2/2] x86, efi: Add "efi_fake_mem_mirror" boot option

Taku Izumi
2015-08-20T17:16:00Z

This patch introduces new boot option named "efi_fake_mem_mirror".
By specifying this parameter, you can mark specific memory as
mirrored memory. This is useful for debugging of Address Range
Mirroring feature.

For example, if you specify "efi_fake_mem_mirror=2G@4G,2G@0x10a0000000",
the original (firmware provided) EFI memmap will be updated so that
the specified memory regions have EFI_MEMORY_MORE_RELIABLE attribute:

<original EFI memmap>
efi: mem00: [Boot Data | | | | | | |WB|WT|WC|UC] range=[0x0000000000000000-0x0000000000001000) (0MB)
efi: mem01: [Loader Data | | | | | | |WB|WT|WC|UC] range=[0x0000000000001000-0x0000000000002000) (0MB)
...
efi: mem35: [Boot Data | | | | | | |WB|WT|WC|UC] range=[0x0000000047ee6000-0x0000000048014000) (1MB)
efi: mem36: [Conventional Memory| | | | | | |WB|WT|WC|UC] range=[0x0000000100000000-0x00000020a0000000) (129536MB)
efi: mem37: [Reserved |RUN| | | | | | | | |UC] range=[0x0000000060000000-0x0000000090000000) (768MB)

<updated EFI memmap>
efi: mem00: [Boot Data | | | | | | |WB|WT|WC|UC] range=[0x0000000000000000-0x0000000000001000) (0MB)
efi: mem01: [Loader Data | | | | | | |WB|WT|WC|UC] range=[0x0000000000001000-0x0000000000002000) (0MB)
...
efi: mem35: [Boot Data | | | | | | |WB|WT|WC|UC] range=[0x0000000047ee6000-0x0000000048014000) (1MB)
efi: mem36: [Conventional Memory| |RELY| | | | |WB|WT|WC|UC] range=[0x0000000100000000-0x0000000180000000) (2048MB)
efi: mem37: [Conventional Memory| | | | | | |WB|WT|WC|UC] range=[0x0000000180000000-0x00000010a0000000) (61952MB)
efi: mem38: [Conventional Memory| |RELY| | | | |WB|WT|WC|UC] range=[0x00000010a0000000-0x0000001120000000) (2048MB)
efi: mem39: [Conventional Memory| | | | | | |WB|WT|WC|UC] range=[0x0000001120000000-0x00000020a0000000) (63488MB)
efi: mem40: [Reserved |RUN| | | | | | | | |UC] range=[0x0000000060000000-0x0000000090000000) (768MB)

And you will find that the following message is output:

efi: Memory: 4096M/131455M mirrored memory

Signed-off-by: Taku Izumi <izumi.taku@jp.fujitsu.com>
---
Documentation/kernel-parameters.txt | 8 ++
arch/x86/include/asm/efi.h | 2 +
arch/x86/kernel/setup.c | 4 +-
arch/x86/platform/efi/efi.c | 2 +-
arch/x86/platform/efi/quirks.c | 169 ++++++++++++++++++++++++++++++++++++
5 files changed, 183 insertions(+), 2 deletions(-)

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 1d6f045..0efded6 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -1092,6 +1092,14 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
you are really sure that your UEFI does sane gc and
fulfills the spec otherwise your board may brick.

+ efi_fake_mem_mirror=nn[KMG]@ss[KMG][,nn[KMG]@ss[KMG],..] [EFI; X86]
+ Mark specific memory as mirrored memory and update
+ EFI memory map.
+ Region of memory to be marked is from ss to ss+nn.
+ Using this parameter you can do debugging of Address
+ Range Mirroring feature even if your box doesn't support
+ it.
+
eisa_irq_edge= [PARISC,HW]
See header of drivers/parisc/eisa.c.

diff --git a/arch/x86/include/asm/efi.h b/arch/x86/include/asm/efi.h
index 155162e..50e53cc 100644
--- a/arch/x86/include/asm/efi.h
+++ b/arch/x86/include/asm/efi.h
@@ -93,6 +93,7 @@ extern void __init efi_set_executable(efi_memory_desc_t *md, bool executable);
extern int __init efi_memblock_x86_reserve_range(void);
extern pgd_t * __init efi_call_phys_prolog(void);
extern void __init efi_call_phys_epilog(pgd_t *save_pgd);
+extern void __init print_efi_memmap(void);
extern void __init efi_unmap_memmap(void);
extern void __init efi_memory_uc(u64 addr, unsigned long size);
extern void __init efi_map_region(efi_memory_desc_t *md);
@@ -107,6 +108,7 @@ extern void __init efi_dump_pagetable(void);
extern void __init efi_apply_memmap_quirks(void);
extern int __init efi_reuse_config(u64 tables, int nr_tables);
extern void efi_delete_dummy_variable(void);
+extern void __init efi_fake_memmap(void);

struct efi_setup_data {
u64 fw_vendor;
diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index 80f874b..e3ed628 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -1104,8 +1104,10 @@ void __init setup_arch(char **cmdline_p)
memblock_set_current_limit(ISA_END_ADDRESS);
memblock_x86_fill();

- if (efi_enabled(EFI_BOOT))
+ if (efi_enabled(EFI_BOOT)) {
+ efi_fake_memmap();
efi_find_mirror();
+ }

/*
* The EFI specification says that boot service code won't be called
diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c
index e4308fe..eee8068 100644
--- a/arch/x86/platform/efi/efi.c
+++ b/arch/x86/platform/efi/efi.c
@@ -222,7 +222,7 @@ int __init efi_memblock_x86_reserve_range(void)
return 0;
}

-static void __init print_efi_memmap(void)
+void __init print_efi_memmap(void)
{
#ifdef EFI_DEBUG
efi_memory_desc_t *md;
diff --git a/arch/x86/platform/efi/quirks.c b/arch/x86/platform/efi/quirks.c
index 1c7380d..5c785e1 100644
--- a/arch/x86/platform/efi/quirks.c
+++ b/arch/x86/platform/efi/quirks.c
@@ -18,6 +18,10 @@

static efi_char16_t efi_dummy_name[6] = { 'D', 'U', 'M', 'M', 'Y', 0 };

+#define EFI_MAX_FAKE_MIRROR 8
+static struct range fake_mirrors[EFI_MAX_FAKE_MIRROR];
+static int num_fake_mirror;
+
static bool efi_no_storage_paranoia;

/*
@@ -288,3 +292,168 @@ bool efi_poweroff_required(void)
{
return !!acpi_gbl_reduced_hardware;
}
+
+void __init efi_fake_memmap(void)
+{
+ efi_memory_desc_t *md;
+ void *p, *q;
+ int i;
+ int nr_map = memmap.nr_map;
+ u64 start, end, m_start, m_end;
+ u64 new_memmap_phy;
+ void *new_memmap;
+
+ if (!num_fake_mirror)
+ return;
+
+ /* count up the number of EFI memory descriptor */
+ for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) {
+ md = p;
+ start = md->phys_addr;
+ end = start + (md->num_pages << EFI_PAGE_SHIFT) - 1;
+
+ for (i = 0; i < num_fake_mirror; i++) {
+ /* mirroring range */
+ m_start = fake_mirrors[i].start;
+ m_end = fake_mirrors[i].end;
+
+ if (m_start <= start) {
+ /* split into 2 parts */
+ if (start < m_end && m_end < end)
+ nr_map++;
+ }
+ if (start < m_start && m_start < end) {
+ /* split into 3 parts */
+ if (m_end < end)
+ nr_map += 2;
+ /* split into 2 parts */
+ if (end <= m_end)
+ nr_map++;
+ }
+ }
+ }
+
+ /* allocate memory for new EFI memmap */
+ new_memmap_phy = memblock_alloc(memmap.desc_size * nr_map, PAGE_SIZE);
+ if (!new_memmap_phy)
+ return;
+
+ /* create new EFI memmap */
+ new_memmap = early_memremap(new_memmap_phy, memmap.desc_size * nr_map);
+ for (p = memmap.map, q = new_memmap;
+ p < memmap.map_end;
+ p += memmap.desc_size, q += memmap.desc_size) {
+
+ /* copy original EFI memory descriptor */
+ memcpy(q, p, memmap.desc_size);
+ md = q;
+ start = md->phys_addr;
+ end = md->phys_addr + (md->num_pages << EFI_PAGE_SHIFT) - 1;
+
+ for (i = 0; i < num_fake_mirror; i++) {
+ /* mirroring range */
+ m_start = fake_mirrors[i].start;
+ m_end = fake_mirrors[i].end;
+
+ if (m_start <= start && end <= m_end)
+ md->attribute |= EFI_MEMORY_MORE_RELIABLE;
+
+ if (m_start <= start &&
+ (start < m_end && m_end < end)) {
+ /* first part */
+ md->attribute |= EFI_MEMORY_MORE_RELIABLE;
+ md->num_pages = (m_end - md->phys_addr + 1) >>
+ EFI_PAGE_SHIFT;
+ /* latter part */
+ q += memmap.desc_size;
+ memcpy(q, p, memmap.desc_size);
+ md = q;
+ md->phys_addr = m_end + 1;
+ md->num_pages = (end - md->phys_addr + 1) >>
+ EFI_PAGE_SHIFT;
+ }
+
+ if ((start < m_start && m_start < end) && m_end < end) {
+ /* first part */
+ md->num_pages = (m_start - md->phys_addr) >>
+ EFI_PAGE_SHIFT;
+ /* middle part */
+ q += memmap.desc_size;
+ memcpy(q, p, memmap.desc_size);
+ md = q;
+ md->attribute |= EFI_MEMORY_MORE_RELIABLE;
+ md->phys_addr = m_start;
+ md->num_pages = (m_end - m_start + 1) >>
+ EFI_PAGE_SHIFT;
+ /* last part */
+ q += memmap.desc_size;
+ memcpy(q, p, memmap.desc_size);
+ md = q;
+ md->phys_addr = m_end + 1;
+ md->num_pages = (end - m_end) >>
+ EFI_PAGE_SHIFT;
+ }
+
+ if ((start < m_start && m_start < end) &&
+ (end <= m_end)) {
+ /* first part */
+ md->num_pages = (m_start - md->phys_addr) >>
+ EFI_PAGE_SHIFT;
+ /* latter part */
+ q += memmap.desc_size;
+ memcpy(q, p, memmap.desc_size);
+ md = q;
+ md->phys_addr = m_start;
+ md->num_pages = (end - md->phys_addr + 1) >>
+ EFI_PAGE_SHIFT;
+ md->attribute |= EFI_MEMORY_MORE_RELIABLE;
+ }
+ }
+ }
+
+ /* swap into new EFI memmap */
+ efi_unmap_memmap();
+ memmap.map = new_memmap;
+ memmap.phys_map = (void *)new_memmap_phy;
+ memmap.nr_map = nr_map;
+ memmap.map_end = memmap.map + memmap.nr_map * memmap.desc_size;
+ set_bit(EFI_MEMMAP, &efi.flags);
+
+ /* print new EFI memmap */
+ print_efi_memmap();
+}
+
+static int __init setup_fake_mem_mirror(char *p)
+{
+ u64 start = 0, mem_size = 0;
+ int i;
+
+ if (!p)
+ return -EINVAL;
+
+ while (*p != '\0') {
+ mem_size = memparse(p, &p);
+ if (*p == '@')
+ start = memparse(p+1, &p);
+ else
+ break;
+
+ num_fake_mirror = add_range_with_merge(fake_mirrors,
+ EFI_MAX_FAKE_MIRROR,
+ num_fake_mirror,
+ start,
+ start + mem_size - 1);
+ if (*p == ',')
+ p++;
+ }
+
+ sort_range(fake_mirrors, num_fake_mirror);
+
+ for (i = 0; i < num_fake_mirror; i++)
+ pr_info("efi_fake_mem_mirror: [mem 0x%016llx-0x%016llx] marked as mirrored memory",
+ fake_mirrors[i].start, fake_mirrors[i].end);
+
+ return *p == '\0' ? 0 : -EINVAL;
+}
+
+early_param("efi_fake_mem_mirror", setup_fake_mem_mirror);
--
1.8.3.1