[GIT PULL] x86/reboot changes for v3.6

From: Ingo Molnar
Date: Sun Jul 22 2012 - 10:10:19 EST

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Linus,

Please pull the latest x86-reboot-for-linus git tree from:

git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git x86-reboot-for-linus

HEAD: 9751d7627582fc1cc64625d63bde9528c14f1544 x86-64, reboot: Be more paranoid in 64-bit reboot=bios

Now that the revampted x86 real-mode trampoline code is upstream
and seems to be working well, we can extend the 64-bit reboot
code to be as capable as the 32-bit one.

Thanks,

Ingo

------------------>
H. Peter Anvin (3):
x86-64, reboot: Allow reboot=bios and reboot-cpu override on x86-64
x86, reboot: Drop redundant write of reboot_mode
x86-64, reboot: Be more paranoid in 64-bit reboot=bios

arch/x86/include/asm/emergency-restart.h | 2 -
arch/x86/include/asm/realmode.h | 3 +-
arch/x86/include/asm/reboot.h | 4 +-
arch/x86/kernel/reboot.c | 60 ++++++++++--------------
arch/x86/realmode/rm/Makefile | 2 +-
arch/x86/realmode/rm/header.S | 4 +-
arch/x86/realmode/rm/{reboot_32.S => reboot.S} | 30 ++++++++++--
7 files changed, 59 insertions(+), 46 deletions(-)
rename arch/x86/realmode/rm/{reboot_32.S => reboot.S} (85%)

diff --git a/arch/x86/include/asm/emergency-restart.h b/arch/x86/include/asm/emergency-restart.h
index cc70c1c..75ce3f4 100644
--- a/arch/x86/include/asm/emergency-restart.h
+++ b/arch/x86/include/asm/emergency-restart.h
@@ -4,9 +4,7 @@
enum reboot_type {
BOOT_TRIPLE = 't',
BOOT_KBD = 'k',
-#ifdef CONFIG_X86_32
BOOT_BIOS = 'b',
-#endif
BOOT_ACPI = 'a',
BOOT_EFI = 'e',
BOOT_CF9 = 'p',
diff --git a/arch/x86/include/asm/realmode.h b/arch/x86/include/asm/realmode.h
index fce3f4a..fe1ec5b 100644
--- a/arch/x86/include/asm/realmode.h
+++ b/arch/x86/include/asm/realmode.h
@@ -21,8 +21,9 @@ struct real_mode_header {
u32 wakeup_header;
#endif
/* APM/BIOS reboot */
-#ifdef CONFIG_X86_32
u32 machine_real_restart_asm;
+#ifdef CONFIG_X86_64
+ u32 machine_real_restart_seg;
#endif
};

diff --git a/arch/x86/include/asm/reboot.h b/arch/x86/include/asm/reboot.h
index 92f29706..a82c4f1 100644
--- a/arch/x86/include/asm/reboot.h
+++ b/arch/x86/include/asm/reboot.h
@@ -18,8 +18,8 @@ extern struct machine_ops machine_ops;

void native_machine_crash_shutdown(struct pt_regs *regs);
void native_machine_shutdown(void);
-void machine_real_restart(unsigned int type);
-/* These must match dispatch_table in reboot_32.S */
+void __noreturn machine_real_restart(unsigned int type);
+/* These must match dispatch in arch/x86/realmore/rm/reboot.S */
#define MRR_BIOS 0
#define MRR_APM 1

diff --git a/arch/x86/kernel/reboot.c b/arch/x86/kernel/reboot.c
index 25b48ed..6ef559f 100644
--- a/arch/x86/kernel/reboot.c
+++ b/arch/x86/kernel/reboot.c
@@ -20,14 +20,12 @@
#include <asm/virtext.h>
#include <asm/cpu.h>
#include <asm/nmi.h>
+#include <asm/smp.h>

-#ifdef CONFIG_X86_32
-# include <linux/ctype.h>
-# include <linux/mc146818rtc.h>
-# include <asm/realmode.h>
-#else
-# include <asm/x86_init.h>
-#endif
+#include <linux/ctype.h>
+#include <linux/mc146818rtc.h>
+#include <asm/realmode.h>
+#include <asm/x86_init.h>

/*
* Power off function, if any
@@ -49,7 +47,7 @@ int reboot_force;
*/
static int reboot_default = 1;

-#if defined(CONFIG_X86_32) && defined(CONFIG_SMP)
+#ifdef CONFIG_SMP
static int reboot_cpu = -1;
#endif

@@ -67,8 +65,8 @@ bool port_cf9_safe = false;
* reboot=b[ios] | s[mp] | t[riple] | k[bd] | e[fi] [, [w]arm | [c]old] | p[ci]
* warm Don't set the cold reboot flag
* cold Set the cold reboot flag
- * bios Reboot by jumping through the BIOS (only for X86_32)
- * smp Reboot by executing reset on BSP or other CPU (only for X86_32)
+ * bios Reboot by jumping through the BIOS
+ * smp Reboot by executing reset on BSP or other CPU
* triple Force a triple fault (init)
* kbd Use the keyboard controller. cold reset (default)
* acpi Use the RESET_REG in the FADT
@@ -95,7 +93,6 @@ static int __init reboot_setup(char *str)
reboot_mode = 0;
break;

-#ifdef CONFIG_X86_32
#ifdef CONFIG_SMP
case 's':
if (isdigit(*(str+1))) {
@@ -112,7 +109,6 @@ static int __init reboot_setup(char *str)
#endif /* CONFIG_SMP */

case 'b':
-#endif
case 'a':
case 'k':
case 't':
@@ -138,7 +134,6 @@ static int __init reboot_setup(char *str)
__setup("reboot=", reboot_setup);

-#ifdef CONFIG_X86_32
/*
* Reboot options and system auto-detection code provided by
* Dell Inc. so their systems "just work". :-)
@@ -157,11 +152,8 @@ static int __init set_bios_reboot(const struct dmi_system_id *d)
return 0;
}

-void machine_real_restart(unsigned int type)
+void __noreturn machine_real_restart(unsigned int type)
{
- void (*restart_lowmem)(unsigned int) = (void (*)(unsigned int))
- real_mode_header->machine_real_restart_asm;
-
local_irq_disable();

/*
@@ -181,25 +173,28 @@ void machine_real_restart(unsigned int type)
/*
* Switch back to the initial page table.
*/
+#ifdef CONFIG_X86_32
load_cr3(initial_page_table);
-
- /*
- * Write 0x1234 to absolute memory location 0x472. The BIOS reads
- * this on booting to tell it to "Bypass memory test (also warm
- * boot)". This seems like a fairly standard thing that gets set by
- * REBOOT.COM programs, and the previous reset routine did this
- * too. */
- *((unsigned short *)0x472) = reboot_mode;
+#else
+ write_cr3(real_mode_header->trampoline_pgd);
+#endif

/* Jump to the identity-mapped low memory code */
- restart_lowmem(type);
+#ifdef CONFIG_X86_32
+ asm volatile("jmpl *%0" : :
+ "rm" (real_mode_header->machine_real_restart_asm),
+ "a" (type));
+#else
+ asm volatile("ljmpl *%0" : :
+ "m" (real_mode_header->machine_real_restart_asm),
+ "D" (type));
+#endif
+ unreachable();
}
#ifdef CONFIG_APM_MODULE
EXPORT_SYMBOL(machine_real_restart);
#endif

-#endif /* CONFIG_X86_32 */
-
/*
* Some Apple MacBook and MacBookPro's needs reboot=p to be able to reboot
*/
@@ -223,11 +218,9 @@ static int __init set_kbd_reboot(const struct dmi_system_id *d)
}

/*
- * This is a single dmi_table handling all reboot quirks. Note that
- * REBOOT_BIOS is only available for 32bit
+ * This is a single dmi_table handling all reboot quirks.
*/
static struct dmi_system_id __initdata reboot_dmi_table[] = {
-#ifdef CONFIG_X86_32
{ /* Handle problems with rebooting on Dell E520's */
.callback = set_bios_reboot,
.ident = "Dell E520",
@@ -377,7 +370,6 @@ static struct dmi_system_id __initdata reboot_dmi_table[] = {
DMI_MATCH(DMI_BOARD_NAME, "P4S800"),
},
},
-#endif /* CONFIG_X86_32 */

{ /* Handle reboot issue on Acer Aspire one */
.callback = set_kbd_reboot,
@@ -576,13 +568,11 @@ static void native_machine_emergency_restart(void)
reboot_type = BOOT_KBD;
break;

-#ifdef CONFIG_X86_32
case BOOT_BIOS:
machine_real_restart(MRR_BIOS);

reboot_type = BOOT_KBD;
break;
-#endif

case BOOT_ACPI:
acpi_reboot();
@@ -624,12 +614,10 @@ void native_machine_shutdown(void)
/* The boot cpu is always logical cpu 0 */
int reboot_cpu_id = 0;

-#ifdef CONFIG_X86_32
/* See if there has been given a command line override */
if ((reboot_cpu != -1) && (reboot_cpu < nr_cpu_ids) &&
cpu_online(reboot_cpu))
reboot_cpu_id = reboot_cpu;
-#endif

/* Make certain the cpu I'm about to reboot on is online */
if (!cpu_online(reboot_cpu_id))
diff --git a/arch/x86/realmode/rm/Makefile b/arch/x86/realmode/rm/Makefile
index 5b84a2d..b2d534c 100644
--- a/arch/x86/realmode/rm/Makefile
+++ b/arch/x86/realmode/rm/Makefile
@@ -22,7 +22,7 @@ wakeup-objs += video-bios.o
realmode-y += header.o
realmode-y += trampoline_$(BITS).o
realmode-y += stack.o
-realmode-$(CONFIG_X86_32) += reboot_32.o
+realmode-y += reboot.o
realmode-$(CONFIG_ACPI_SLEEP) += $(wakeup-objs)

targets += $(realmode-y)
diff --git a/arch/x86/realmode/rm/header.S b/arch/x86/realmode/rm/header.S
index fadf483..a28221d 100644
--- a/arch/x86/realmode/rm/header.S
+++ b/arch/x86/realmode/rm/header.S
@@ -6,6 +6,7 @@

#include <linux/linkage.h>
#include <asm/page_types.h>
+#include <asm/segment.h>

#include "realmode.h"

@@ -28,8 +29,9 @@ GLOBAL(real_mode_header)
.long pa_wakeup_header
#endif
/* APM/BIOS reboot */
-#ifdef CONFIG_X86_32
.long pa_machine_real_restart_asm
+#ifdef CONFIG_X86_64
+ .long __KERNEL32_CS
#endif
END(real_mode_header)

diff --git a/arch/x86/realmode/rm/reboot_32.S b/arch/x86/realmode/rm/reboot.S
similarity index 85%
rename from arch/x86/realmode/rm/reboot_32.S
rename to arch/x86/realmode/rm/reboot.S
index 1140448..f932ea6 100644
--- a/arch/x86/realmode/rm/reboot_32.S
+++ b/arch/x86/realmode/rm/reboot.S
@@ -2,6 +2,8 @@
#include <linux/init.h>
#include <asm/segment.h>
#include <asm/page_types.h>
+#include <asm/processor-flags.h>
+#include <asm/msr-index.h>
#include "realmode.h"

/*
@@ -12,13 +14,35 @@
* doesn't work with at least one type of 486 motherboard. It is easy
* to stop this code working; hence the copious comments.
*
- * This code is called with the restart type (0 = BIOS, 1 = APM) in %eax.
+ * This code is called with the restart type (0 = BIOS, 1 = APM) in
+ * the primary argument register (%eax for 32 bit, %edi for 64 bit).
*/
.section ".text32", "ax"
.code32
-
- .balign 16
ENTRY(machine_real_restart_asm)
+
+#ifdef CONFIG_X86_64
+ /* Switch to trampoline GDT as it is guaranteed < 4 GiB */
+ movl $__KERNEL_DS, %eax
+ movl %eax, %ds
+ lgdtl pa_tr_gdt
+
+ /* Disable paging to drop us out of long mode */
+ movl %cr0, %eax
+ andl $~X86_CR0_PG, %eax
+ movl %eax, %cr0
+ ljmpl $__KERNEL32_CS, $pa_machine_real_restart_paging_off
+
+GLOBAL(machine_real_restart_paging_off)
+ xorl %eax, %eax
+ xorl %edx, %edx
+ movl $MSR_EFER, %ecx
+ wrmsr
+
+ movl %edi, %eax
+
+#endif /* CONFIG_X86_64 */
+
/* Set up the IDT for real mode. */
lidtl pa_machine_real_restart_idt

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Next message: Ingo Molnar: "[GIT PULL] x86/uv changes for v3.6"
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