Hi Linus,
Additional x86 fixes. Three of these patches are pure documentation,
two are pretty trivial; the remaining one fixes boot problems on
some non-BIOS machines.
The following changes since commit a8aed3e0752b4beb2e37cbed6df69faae88268da:
x86/mm/pageattr: Prevent PSE and GLOABL leftovers to confuse pmd/pte_present and pmd_huge (2013-02-24 13:01:45 +0100)
are available in the git repository at:
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git x86-urgent-for-linus
for you to fetch changes up to 7c10093692ed2e6f318387d96b829320aa0ca64c:
x86: Make sure we can boot in the case the BDA contains pure garbage (2013-02-27 13:38:57 -0800)
----------------------------------------------------------------
H. Peter Anvin (1):
x86: Make sure we can boot in the case the BDA contains pure garbage
Konrad Rzeszutek Wilk (3):
doc, xen: Mention 'earlyprintk=xen' in the documentation.
doc, kernel-parameters: Document 'console=hvc<n>'
x86, doc: Fix incorrect comment about 64-bit code segment descriptors
Matt Fleming (1):
x86, efi: Mark disable_runtime as __initdata
Thomas Renninger (1):
ACPI: Overriding ACPI tables via initrd only works with an initrd and on X86
Documentation/kernel-parameters.txt | 5 ++++
arch/x86/kernel/head.c | 53 ++++++++++++++++++++++++-------------
arch/x86/kernel/head_64.S | 4 +--
arch/x86/platform/efi/efi.c | 2 +-
drivers/acpi/Kconfig | 3 ++-
5 files changed, 44 insertions(+), 23 deletions(-)
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 6c72381..986614d 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -564,6 +564,8 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
UART at the specified I/O port or MMIO address,
switching to the matching ttyS device later. The
options are the same as for ttyS, above.
+ hvc<n> Use the hypervisor console device <n>. This is for
+ both Xen and PowerPC hypervisors.
If the device connected to the port is not a TTY but a braille
device, prepend "brl," before the device type, for instance
@@ -754,6 +756,7 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
earlyprintk= [X86,SH,BLACKFIN]
earlyprintk=vga
+ earlyprintk=xen
earlyprintk=serial[,ttySn[,baudrate]]
earlyprintk=ttySn[,baudrate]
earlyprintk=dbgp[debugController#]
@@ -771,6 +774,8 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
The VGA output is eventually overwritten by the real
console.
+ The xen output can only be used by Xen PV guests.
+
ekgdboc= [X86,KGDB] Allow early kernel console debugging
ekgdboc=kbd
diff --git a/arch/x86/kernel/head.c b/arch/x86/kernel/head.c
index 48d9d4e..992f442 100644
--- a/arch/x86/kernel/head.c
+++ b/arch/x86/kernel/head.c
@@ -5,8 +5,6 @@
#include <asm/setup.h>
#include <asm/bios_ebda.h>
-#define BIOS_LOWMEM_KILOBYTES 0x413
-
/*
* The BIOS places the EBDA/XBDA at the top of conventional
* memory, and usually decreases the reported amount of
@@ -16,17 +14,30 @@
* chipset: reserve a page before VGA to prevent PCI prefetch
* into it (errata #56). Usually the page is reserved anyways,
* unless you have no PS/2 mouse plugged in.
+ *
+ * This functions is deliberately very conservative. Losing
+ * memory in the bottom megabyte is rarely a problem, as long
+ * as we have enough memory to install the trampoline. Using
+ * memory that is in use by the BIOS or by some DMA device
+ * the BIOS didn't shut down *is* a big problem.
*/
+
+#define BIOS_LOWMEM_KILOBYTES 0x413
+#define LOWMEM_CAP 0x9f000U /* Absolute maximum */
+#define INSANE_CUTOFF 0x20000U /* Less than this = insane */
+
void __init reserve_ebda_region(void)
{
unsigned int lowmem, ebda_addr;
- /* To determine the position of the EBDA and the */
- /* end of conventional memory, we need to look at */
- /* the BIOS data area. In a paravirtual environment */
- /* that area is absent. We'll just have to assume */
- /* that the paravirt case can handle memory setup */
- /* correctly, without our help. */
+ /*
+ * To determine the position of the EBDA and the
+ * end of conventional memory, we need to look at
+ * the BIOS data area. In a paravirtual environment
+ * that area is absent. We'll just have to assume
+ * that the paravirt case can handle memory setup
+ * correctly, without our help.
+ */
if (paravirt_enabled())
return;
@@ -37,19 +48,23 @@ void __init reserve_ebda_region(void)
/* start of EBDA area */
ebda_addr = get_bios_ebda();
- /* Fixup: bios puts an EBDA in the top 64K segment */
- /* of conventional memory, but does not adjust lowmem. */
- if ((lowmem - ebda_addr) <= 0x10000)
- lowmem = ebda_addr;
+ /*
+ * Note: some old Dells seem to need 4k EBDA without
+ * reporting so, so just consider the memory above 0x9f000
+ * to be off limits (bugzilla 2990).
+ */
+
+ /* If the EBDA address is below 128K, assume it is bogus */
+ if (ebda_addr < INSANE_CUTOFF)
+ ebda_addr = LOWMEM_CAP;
- /* Fixup: bios does not report an EBDA at all. */
- /* Some old Dells seem to need 4k anyhow (bugzilla 2990) */
- if ((ebda_addr == 0) && (lowmem >= 0x9f000))
- lowmem = 0x9f000;
+ /* If lowmem is less than 128K, assume it is bogus */
+ if (lowmem < INSANE_CUTOFF)
+ lowmem = LOWMEM_CAP;
- /* Paranoia: should never happen, but... */
- if ((lowmem == 0) || (lowmem >= 0x100000))
- lowmem = 0x9f000;
+ /* Use the lower of the lowmem and EBDA markers as the cutoff */
+ lowmem = min(lowmem, ebda_addr);
+ lowmem = min(lowmem, LOWMEM_CAP); /* Absolute cap */
/* reserve all memory between lowmem and the 1MB mark */
memblock_reserve(lowmem, 0x100000 - lowmem);
diff --git a/arch/x86/kernel/head_64.S b/arch/x86/kernel/head_64.S
index 980053c..37f5304 100644
--- a/arch/x86/kernel/head_64.S
+++ b/arch/x86/kernel/head_64.S
@@ -49,7 +49,7 @@ L3_START_KERNEL = pud_index(__START_KERNEL_map)
startup_64:
/*
- * At this point the CPU runs in 64bit mode CS.L = 1 CS.D = 1,
+ * At this point the CPU runs in 64bit mode CS.L = 1 CS.D = 0,
* and someone has loaded an identity mapped page table
* for us. These identity mapped page tables map all of the
* kernel pages and possibly all of memory.
@@ -146,7 +146,7 @@ ident_complete:
jmp secondary_startup_64
ENTRY(secondary_startup_64)
/*
- * At this point the CPU runs in 64bit mode CS.L = 1 CS.D = 1,
+ * At this point the CPU runs in 64bit mode CS.L = 1 CS.D = 0,
* and someone has loaded a mapped page table.
*
* %esi holds a physical pointer to real_mode_data.
diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c
index e2cd38f..ec9f325 100644
--- a/arch/x86/platform/efi/efi.c
+++ b/arch/x86/platform/efi/efi.c
@@ -85,7 +85,7 @@ int efi_enabled(int facility)
}
EXPORT_SYMBOL(efi_enabled);
-static bool disable_runtime = false;
+static bool __initdata disable_runtime = false;
static int __init setup_noefi(char *arg)
{
disable_runtime = true;
diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig
index 38c5078..f5ae996 100644
--- a/drivers/acpi/Kconfig
+++ b/drivers/acpi/Kconfig
@@ -268,7 +268,8 @@ config ACPI_CUSTOM_DSDT
default ACPI_CUSTOM_DSDT_FILE != ""
config ACPI_INITRD_TABLE_OVERRIDE
- bool "ACPI tables can be passed via uncompressed cpio in initrd"
+ bool "ACPI tables override via initrd"
+ depends on BLK_DEV_INITRD && X86
default n
help
This option provides functionality to override arbitrary ACPI tables
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