From f12d3d04e8f6223276abb068c5d72852174b8c31 Mon Sep 17 00:00:00 2001
From: Matthieu CASTET <castet.matthieu@free.fr>
Date: Thu, 20 Jan 2011 21:11:45 +0100
Subject: [PATCH 1/3] x86, nx: Don't force pages RW when setting NX bits
Xen want page table pages read only.
But the initial page table (from head_*.S) live in .data or .bss.
That was broken by 64edc8ed5ffae999d8d413ba006850e9e34166cb. There is
absolutely no reason to force these pages RW after they have already
been marked RO.
Signed-off-by: Matthieu CASTET <castet.matthieu@free.fr>
Tested-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
---
arch/x86/mm/pageattr.c | 8 --------
1 file changed, 8 deletions(-)
diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c
index 8b830ca14ac46..d343b3c81f3c1 100644
--- a/arch/x86/mm/pageattr.c
+++ b/arch/x86/mm/pageattr.c
@@ -256,7 +256,6 @@ static inline pgprot_t static_protections(pgprot_t prot, unsigned long address,
unsigned long pfn)
{
pgprot_t forbidden = __pgprot(0);
- pgprot_t required = __pgprot(0);
/*
* The BIOS area between 640k and 1Mb needs to be executable for
@@ -282,12 +281,6 @@ static inline pgprot_t static_protections(pgprot_t prot, unsigned long address,
if (within(pfn, __pa((unsigned long)__start_rodata) >> PAGE_SHIFT,
__pa((unsigned long)__end_rodata) >> PAGE_SHIFT))
pgprot_val(forbidden) |= _PAGE_RW;
- /*
- * .data and .bss should always be writable.
- */
- if (within(address, (unsigned long)_sdata, (unsigned long)_edata) ||
- within(address, (unsigned long)__bss_start, (unsigned long)__bss_stop))
- pgprot_val(required) |= _PAGE_RW;
#if defined(CONFIG_X86_64) && defined(CONFIG_DEBUG_RODATA)
/*
@@ -327,7 +320,6 @@ static inline pgprot_t static_protections(pgprot_t prot, unsigned long address,
#endif
prot = __pgprot(pgprot_val(prot) & ~pgprot_val(forbidden));
- prot = __pgprot(pgprot_val(prot) | pgprot_val(required));
return prot;
}
From f7448548a9f32db38f243ccd4271617758ddfe2c Mon Sep 17 00:00:00 2001
From: Suresh Siddha <suresh.b.siddha@intel.com>
Date: Wed, 2 Feb 2011 17:02:55 -0800
Subject: [PATCH 2/3] x86, mtrr: Avoid MTRR reprogramming on BP during boot on
UP platforms
Markus Kohn ran into a hard hang regression on an acer aspire
1310, when acpi is enabled. git bisect showed the following
commit as the bad one that introduced the boot regression.
commit d0af9eed5aa91b6b7b5049cae69e5ea956fd85c3
Author: Suresh Siddha <suresh.b.siddha@intel.com>
Date: Wed Aug 19 18:05:36 2009 -0700
x86, pat/mtrr: Rendezvous all the cpus for MTRR/PAT init
Because of the UP configuration of that platform,
native_smp_prepare_cpus() bailed out (in smp_sanity_check())
before doing the set_mtrr_aps_delayed_init()
Further down the boot path, native_smp_cpus_done() will call the
delayed MTRR initialization for the AP's (mtrr_aps_init()) with
mtrr_aps_delayed_init not set. This resulted in the boot
processor reprogramming its MTRR's to the values seen during the
start of the OS boot. While this is not needed ideally, this
shouldn't have caused any side-effects. This is because the
reprogramming of MTRR's (set_mtrr_state() that gets called via
set_mtrr()) will check if the live register contents are
different from what is being asked to write and will do the actual
write only if they are different.
BP's mtrr state is read during the start of the OS boot and
typically nothing would have changed when we ask to reprogram it
on BP again because of the above scenario on an UP platform. So
on a normal UP platform no reprogramming of BP MTRR MSR's
happens and all is well.
However, on this platform, bios seems to be modifying the fixed
mtrr range registers between the start of OS boot and when we
double check the live registers for reprogramming BP MTRR
registers. And as the live registers are modified, we end up
reprogramming the MTRR's to the state seen during the start of
the OS boot.
During ACPI initialization, something in the bios (probably smi
handler?) don't like this fact and results in a hard lockup.
We didn't see this boot hang issue on this platform before the
commit d0af9eed5aa91b6b7b5049cae69e5ea956fd85c3, because only
the AP's (if any) will program its MTRR's to the value that BP
had at the start of the OS boot.
Fix this issue by checking mtrr_aps_delayed_init before
continuing further in the mtrr_aps_init(). Now, only AP's (if
any) will program its MTRR's to the BP values during boot.
Addresses https://bugzilla.novell.com/show_bug.cgi?id=623393
[ By the way, this behavior of the bios modifying MTRR's after the start
of the OS boot is not common and the kernel is not prepared to
handle this situation well. Irrespective of this issue, during
suspend/resume, linux kernel will try to reprogram the BP's MTRR values
to the values seen during the start of the OS boot. So suspend/resume might
be already broken on this platform for all linux kernel versions. ]
Reported-and-bisected-by: Markus Kohn <jabber@gmx.org>
Tested-by: Markus Kohn <jabber@gmx.org>
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: Thomas Renninger <trenn@novell.com>
Cc: Rafael Wysocki <rjw@novell.com>
Cc: Venkatesh Pallipadi <venki@google.com>
Cc: stable@kernel.org # [v2.6.32+]
LKML-Reference: <1296694975.4418.402.camel@sbsiddha-MOBL3.sc.intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
arch/x86/kernel/cpu/mtrr/main.c | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)
diff --git a/arch/x86/kernel/cpu/mtrr/main.c b/arch/x86/kernel/cpu/mtrr/main.c
index 01c0f3ee6cc3a..bebabec5b448d 100644
--- a/arch/x86/kernel/cpu/mtrr/main.c
+++ b/arch/x86/kernel/cpu/mtrr/main.c
@@ -793,13 +793,21 @@ void set_mtrr_aps_delayed_init(void)
}
/*
- * MTRR initialization for all AP's
+ * Delayed MTRR initialization for all AP's
*/
void mtrr_aps_init(void)
{
if (!use_intel())
return;
+ /*
+ * Check if someone has requested the delay of AP MTRR initialization,
+ * by doing set_mtrr_aps_delayed_init(), prior to this point. If not,
+ * then we are done.
+ */
+ if (!mtrr_aps_delayed_init)
+ return;
+
set_mtrr(~0U, 0, 0, 0);
mtrr_aps_delayed_init = false;
}
From 11d4c3f9b671720e80353dd7e433ff2bf65e9500 Mon Sep 17 00:00:00 2001
From: "H. Peter Anvin" <hpa@linux.intel.com>
Date: Fri, 4 Feb 2011 16:14:11 -0800
Subject: [PATCH 3/3] x86-32: Make sure the stack is set up before we use it
Since checkin ebba638ae723d8a8fc2f7abce5ec18b688b791d7 we call
verify_cpu even in 32-bit mode. Unfortunately, calling a function
means using the stack, and the stack pointer was not initialized in
the 32-bit setup code! This code initializes the stack pointer, and
simplifies the interface slightly since it is easier to rely on just a
pointer value rather than a descriptor; we need to have different
values for the segment register anyway.
This retains start_stack as a virtual address, even though a physical
address would be more convenient for 32 bits; the 64-bit code wants
the other way around...
Reported-by: Matthieu Castet <castet.matthieu@free.fr>
LKML-Reference: <4D41E86D.8060205@free.fr>
Tested-by: Kees Cook <kees.cook@canonical.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
---
arch/x86/include/asm/smp.h | 5 +----
arch/x86/kernel/acpi/sleep.c | 2 +-
arch/x86/kernel/head_32.S | 30 +++++++++++++-----------------
arch/x86/kernel/smpboot.c | 4 ++--
4 files changed, 17 insertions(+), 24 deletions(-)
diff --git a/arch/x86/include/asm/smp.h b/arch/x86/include/asm/smp.h
index 4c2f63c7fc1b2..1f46951367763 100644
--- a/arch/x86/include/asm/smp.h
+++ b/arch/x86/include/asm/smp.h
@@ -40,10 +40,7 @@ DECLARE_EARLY_PER_CPU(u16, x86_cpu_to_apicid);
DECLARE_EARLY_PER_CPU(u16, x86_bios_cpu_apicid);
/* Static state in head.S used to set up a CPU */
-extern struct {
- void *sp;
- unsigned short ss;
-} stack_start;
+extern unsigned long stack_start; /* Initial stack pointer address */
struct smp_ops {
void (*smp_prepare_boot_cpu)(void);
diff --git a/arch/x86/kernel/acpi/sleep.c b/arch/x86/kernel/acpi/sleep.c
index 69fd72aa5594b..4d9ebbab22304 100644
--- a/arch/x86/kernel/acpi/sleep.c
+++ b/arch/x86/kernel/acpi/sleep.c
@@ -100,7 +100,7 @@ int acpi_save_state_mem(void)
#else /* CONFIG_64BIT */
header->trampoline_segment = setup_trampoline() >> 4;
#ifdef CONFIG_SMP
- stack_start.sp = temp_stack + sizeof(temp_stack);
+ stack_start = (unsigned long)temp_stack + sizeof(temp_stack);
early_gdt_descr.address =
(unsigned long)get_cpu_gdt_table(smp_processor_id());
initial_gs = per_cpu_offset(smp_processor_id());
diff --git a/arch/x86/kernel/head_32.S b/arch/x86/kernel/head_32.S
index fc293dc8dc355..767d6c43de372 100644
--- a/arch/x86/kernel/head_32.S
+++ b/arch/x86/kernel/head_32.S
@@ -85,6 +85,8 @@ RESERVE_BRK(pagetables, INIT_MAP_SIZE)
*/
__HEAD
ENTRY(startup_32)
+ movl pa(stack_start),%ecx
+
/* test KEEP_SEGMENTS flag to see if the bootloader is asking
us to not reload segments */
testb $(1<<6), BP_loadflags(%esi)
@@ -99,7 +101,9 @@ ENTRY(startup_32)
movl %eax,%es
movl %eax,%fs
movl %eax,%gs
+ movl %eax,%ss
2:
+ leal -__PAGE_OFFSET(%ecx),%esp
/*
* Clear BSS first so that there are no surprises...
@@ -145,8 +149,6 @@ ENTRY(startup_32)
* _brk_end is set up to point to the first "safe" location.
* Mappings are created both at virtual address 0 (identity mapping)
* and PAGE_OFFSET for up to _end.
- *
- * Note that the stack is not yet set up!
*/
#ifdef CONFIG_X86_PAE
@@ -282,6 +284,9 @@ ENTRY(startup_32_smp)
movl %eax,%es
movl %eax,%fs
movl %eax,%gs
+ movl pa(stack_start),%ecx
+ movl %eax,%ss
+ leal -__PAGE_OFFSET(%ecx),%esp
#endif /* CONFIG_SMP */
default_entry:
@@ -347,8 +352,8 @@ default_entry:
movl %eax,%cr0 /* ..and set paging (PG) bit */
ljmp $__BOOT_CS,$1f /* Clear prefetch and normalize %eip */
1:
- /* Set up the stack pointer */
- lss stack_start,%esp
+ /* Shift the stack pointer to a virtual address */
+ addl $__PAGE_OFFSET, %esp
/*
* Initialize eflags. Some BIOS's leave bits like NT set. This would
@@ -360,9 +365,7 @@ default_entry:
#ifdef CONFIG_SMP
cmpb $0, ready
- jz 1f /* Initial CPU cleans BSS */
- jmp checkCPUtype
-1:
+ jnz checkCPUtype
#endif /* CONFIG_SMP */
/*
@@ -470,14 +473,7 @@ is386: movl $2,%ecx # set MP
cld # gcc2 wants the direction flag cleared at all times
pushl $0 # fake return address for unwinder
-#ifdef CONFIG_SMP
- movb ready, %cl
movb $1, ready
- cmpb $0,%cl # the first CPU calls start_kernel
- je 1f
- movl (stack_start), %esp
-1:
-#endif /* CONFIG_SMP */
jmp *(initial_code)
/*
@@ -670,15 +666,15 @@ ENTRY(initial_page_table)
#endif
.data
+.balign 4
ENTRY(stack_start)
.long init_thread_union+THREAD_SIZE
- .long __BOOT_DS
-
-ready: .byte 0
early_recursion_flag:
.long 0
+ready: .byte 0
+
int_msg:
.asciz "Unknown interrupt or fault at: %p %p %p\n"
diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index 0cbe8c0b35edd..03273b6c272c8 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -638,7 +638,7 @@ wakeup_secondary_cpu_via_init(int phys_apicid, unsigned long start_eip)
* target processor state.
*/
startup_ipi_hook(phys_apicid, (unsigned long) start_secondary,
- (unsigned long)stack_start.sp);
+ stack_start);
/*
* Run STARTUP IPI loop.
@@ -785,7 +785,7 @@ static int __cpuinit do_boot_cpu(int apicid, int cpu)
#endif
early_gdt_descr.address = (unsigned long)get_cpu_gdt_table(cpu);
initial_code = (unsigned long)start_secondary;
- stack_start.sp = (void *) c_idle.idle->thread.sp;
+ stack_start = c_idle.idle->thread.sp;
/* start_ip had better be page-aligned! */
start_ip = setup_trampoline();