Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull more x86 fixes from Peter Anvin: "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." * 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86: Make sure we can boot in the case the BDA contains pure garbage x86, efi: Mark disable_runtime as __initdata x86, doc: Fix incorrect comment about 64-bit code segment descriptors doc, kernel-parameters: Document 'console=hvc<n>' doc, xen: Mention 'earlyprintk=xen' in the documentation. ACPI: Overriding ACPI tables via initrd only works with an initrd and on X86

Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull more x86 fixes from Peter Anvin: "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." * 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86: Make sure we can boot in the case the BDA contains pure garbage x86, efi: Mark disable_runtime as __initdata x86, doc: Fix incorrect comment about 64-bit code segment descriptors doc, kernel-parameters: Document 'console=hvc<n>' doc, xen: Mention 'earlyprintk=xen' in the documentation. ACPI: Overriding ACPI tables via initrd only works with an initrd and on X86
Linus Torvalds
2 parents 309667e53f 7c10093692
Showing 5 changed files Side-by-side Diff
Documentation/kernel-parameters.txt
arch/x86/kernel/head.c
arch/x86/kernel/head_64.S
arch/x86/platform/efi/efi.c
drivers/acpi/Kconfig
@@ -564,6 +564,8 @@
 			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
@@ -757,6 +759,7 @@
  
 	earlyprintk=	[X86,SH,BLACKFIN]
 			earlyprintk=vga
+			earlyprintk=xen
 			earlyprintk=serial[,ttySn[,baudrate]]
 			earlyprintk=ttySn[,baudrate]
 			earlyprintk=dbgp[debugController#]
@@ -773,6 +776,8 @@
  
 			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
@@ -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 @@
 	/* 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).
+	 */
  
-	/* 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 the EBDA address is below 128K, assume it is bogus */
+	if (ebda_addr < INSANE_CUTOFF)
+		ebda_addr = LOWMEM_CAP;
  
-	/* Paranoia: should never happen, but... */
-	if ((lowmem == 0) || (lowmem >= 0x100000))
-		lowmem = 0x9f000;
+	/* If lowmem is less than 128K, assume it is bogus */
+	if (lowmem < INSANE_CUTOFF)
+		lowmem = LOWMEM_CAP;
+
+	/* 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);
@@ -48,7 +48,7 @@
 	.globl startup_64
 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.
@@ -159,7 +159,7 @@
 	jmp 1f
 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.
 	 *
 	 * %rsi holds a physical pointer to real_mode_data.
@@ -85,7 +85,7 @@
 }
 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;
@@ -266,7 +266,8 @@
 	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
...	...	@@ -564,6 +564,8 @@
564	564	UART at the specified I/O port or MMIO address,
565	565	switching to the matching ttyS device later. The
566	566	options are the same as for ttyS, above.
	567	+ hvc<n> Use the hypervisor console device <n>. This is for
	568	+ both Xen and PowerPC hypervisors.
567	569
568	570	If the device connected to the port is not a TTY but a braille
569	571	device, prepend "brl," before the device type, for instance
...	...	@@ -757,6 +759,7 @@
757	759
758	760	earlyprintk= [X86,SH,BLACKFIN]
759	761	earlyprintk=vga
	762	+ earlyprintk=xen
760	763	earlyprintk=serial[,ttySn[,baudrate]]
761	764	earlyprintk=ttySn[,baudrate]
762	765	earlyprintk=dbgp[debugController#]
...	...	@@ -773,6 +776,8 @@
773	776
774	777	The VGA output is eventually overwritten by the real
775	778	console.
	779	+
	780	+ The xen output can only be used by Xen PV guests.
776	781
777	782	ekgdboc= [X86,KGDB] Allow early kernel console debugging
778	783	ekgdboc=kbd
...	...	@@ -5,8 +5,6 @@
5	5	#include <asm/setup.h>
6	6	#include <asm/bios_ebda.h>
7	7
8		-#define BIOS_LOWMEM_KILOBYTES 0x413
9		-
10	8	/*
11	9	* The BIOS places the EBDA/XBDA at the top of conventional
12	10	* memory, and usually decreases the reported amount of
13	11
14	12
...	...	@@ -16,17 +14,30 @@
16	14	* chipset: reserve a page before VGA to prevent PCI prefetch
17	15	* into it (errata #56). Usually the page is reserved anyways,
18	16	* unless you have no PS/2 mouse plugged in.
	17	+ *
	18	+ * This functions is deliberately very conservative. Losing
	19	+ * memory in the bottom megabyte is rarely a problem, as long
	20	+ * as we have enough memory to install the trampoline. Using
	21	+ * memory that is in use by the BIOS or by some DMA device
	22	+ * the BIOS didn't shut down is a big problem.
19	23	*/
	24	+
	25	+#define BIOS_LOWMEM_KILOBYTES 0x413
	26	+#define LOWMEM_CAP 0x9f000U /* Absolute maximum */
	27	+#define INSANE_CUTOFF 0x20000U /* Less than this = insane */
	28	+
20	29	void __init reserve_ebda_region(void)
21	30	{
22	31	unsigned int lowmem, ebda_addr;
23	32
24		- /* To determine the position of the EBDA and the */
25		- /* end of conventional memory, we need to look at */
26		- /* the BIOS data area. In a paravirtual environment */
27		- /* that area is absent. We'll just have to assume */
28		- /* that the paravirt case can handle memory setup */
29		- /* correctly, without our help. */
	33	+ /*
	34	+ * To determine the position of the EBDA and the
	35	+ * end of conventional memory, we need to look at
	36	+ * the BIOS data area. In a paravirtual environment
	37	+ * that area is absent. We'll just have to assume
	38	+ * that the paravirt case can handle memory setup
	39	+ * correctly, without our help.
	40	+ */
30	41	if (paravirt_enabled())
31	42	return;
32	43
33	44
34	45
...	...	@@ -37,19 +48,23 @@
37	48	/* start of EBDA area */
38	49	ebda_addr = get_bios_ebda();
39	50
40		- /* Fixup: bios puts an EBDA in the top 64K segment */
41		- /* of conventional memory, but does not adjust lowmem. */
42		- if ((lowmem - ebda_addr) <= 0x10000)
43		- lowmem = ebda_addr;
	51	+ /*
	52	+ * Note: some old Dells seem to need 4k EBDA without
	53	+ * reporting so, so just consider the memory above 0x9f000
	54	+ * to be off limits (bugzilla 2990).
	55	+ */
44	56
45		- /* Fixup: bios does not report an EBDA at all. */
46		- /* Some old Dells seem to need 4k anyhow (bugzilla 2990) */
47		- if ((ebda_addr == 0) && (lowmem >= 0x9f000))
48		- lowmem = 0x9f000;
	57	+ /* If the EBDA address is below 128K, assume it is bogus */
	58	+ if (ebda_addr < INSANE_CUTOFF)
	59	+ ebda_addr = LOWMEM_CAP;
49	60
50		- /* Paranoia: should never happen, but... */
51		- if ((lowmem == 0) \|\| (lowmem >= 0x100000))
52		- lowmem = 0x9f000;
	61	+ /* If lowmem is less than 128K, assume it is bogus */
	62	+ if (lowmem < INSANE_CUTOFF)
	63	+ lowmem = LOWMEM_CAP;
	64	+
	65	+ /* Use the lower of the lowmem and EBDA markers as the cutoff */
	66	+ lowmem = min(lowmem, ebda_addr);
	67	+ lowmem = min(lowmem, LOWMEM_CAP); /* Absolute cap */
53	68
54	69	/* reserve all memory between lowmem and the 1MB mark */
55	70	memblock_reserve(lowmem, 0x100000 - lowmem);
...	...	@@ -48,7 +48,7 @@
48	48	.globl startup_64
49	49	startup_64:
50	50	/*
51		- * At this point the CPU runs in 64bit mode CS.L = 1 CS.D = 1,
	51	+ * At this point the CPU runs in 64bit mode CS.L = 1 CS.D = 0,
52	52	* and someone has loaded an identity mapped page table
53	53	* for us. These identity mapped page tables map all of the
54	54	* kernel pages and possibly all of memory.
...	...	@@ -159,7 +159,7 @@
159	159	jmp 1f
160	160	ENTRY(secondary_startup_64)
161	161	/*
162		- * At this point the CPU runs in 64bit mode CS.L = 1 CS.D = 1,
	162	+ * At this point the CPU runs in 64bit mode CS.L = 1 CS.D = 0,
163	163	* and someone has loaded a mapped page table.
164	164	*
165	165	* %rsi holds a physical pointer to real_mode_data.
...	...	@@ -85,7 +85,7 @@
85	85	}
86	86	EXPORT_SYMBOL(efi_enabled);
87	87
88		-static bool disable_runtime = false;
	88	+static bool __initdata disable_runtime = false;
89	89	static int __init setup_noefi(char *arg)
90	90	{
91	91	disable_runtime = true;
...	...	@@ -266,7 +266,8 @@
266	266	default ACPI_CUSTOM_DSDT_FILE != ""
267	267
268	268	config ACPI_INITRD_TABLE_OVERRIDE
269		- bool "ACPI tables can be passed via uncompressed cpio in initrd"
	269	+ bool "ACPI tables override via initrd"
	270	+ depends on BLK_DEV_INITRD && X86
270	271	default n
271	272	help
272	273	This option provides functionality to override arbitrary ACPI tables