From 93dbda7cbcd70a0bd1a99f39f44a9ccde8ab9040 Mon Sep 17 00:00:00 2001
From: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Date: Thu, 26 Feb 2009 17:35:44 -0800
Subject: x86: add brk allocation for very, very early allocations
Impact: new interface
Add a brk()-like allocator which effectively extends the bss in order
to allow very early code to do dynamic allocations. This is better than
using statically allocated arrays for data in subsystems which may never
get used.
The space for brk allocations is in the bss ELF segment, so that the
space is mapped properly by the code which maps the kernel, and so
that bootloaders keep the space free rather than putting a ramdisk or
something into it.
The bss itself, delimited by __bss_stop, ends before the brk area
(__brk_base to __brk_limit). The kernel text, data and bss is reserved
up to __bss_stop.
Any brk-allocated data is reserved separately just before the kernel
pagetable is built, as that code allocates from unreserved spaces
in the e820 map, potentially allocating from any unused brk memory.
Ultimately any unused memory in the brk area is used in the general
kernel memory pool.
Initially the brk space is set to 1MB, which is probably much larger
than any user needs (the largest current user is i386 head_32.S's code
to build the pagetables to map the kernel, which can get fairly large
with a big kernel image and no PSE support). So long as the system
has sufficient memory for the bootloader to reserve the kernel+1MB brk,
there are no bad effects resulting from an over-large brk.
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
---
arch/x86/xen/mmu.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
(limited to 'arch/x86/xen/mmu.c')
diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c
index cb6afa4ec95..72f6a76dbfb 100644
--- a/arch/x86/xen/mmu.c
+++ b/arch/x86/xen/mmu.c
@@ -1723,9 +1723,9 @@ __init pgd_t *xen_setup_kernel_pagetable(pgd_t *pgd,
{
pmd_t *kernel_pmd;
- init_pg_tables_start = __pa(pgd);
- init_pg_tables_end = __pa(pgd) + xen_start_info->nr_pt_frames*PAGE_SIZE;
- max_pfn_mapped = PFN_DOWN(init_pg_tables_end + 512*1024);
+ max_pfn_mapped = PFN_DOWN(__pa(xen_start_info->pt_base) +
+ xen_start_info->nr_pt_frames * PAGE_SIZE +
+ 512*1024);
kernel_pmd = m2v(pgd[KERNEL_PGD_BOUNDARY].pgd);
memcpy(level2_kernel_pgt, kernel_pmd, sizeof(pmd_t) * PTRS_PER_PMD);
--
cgit v1.2.3-70-g09d2
From 71ff49d71bb5cfcd2689b54cb433c0e6990a1d86 Mon Sep 17 00:00:00 2001
From: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Date: Wed, 18 Mar 2009 13:03:33 -0700
Subject: x86: with the last user gone, remove set_pte_present
Impact: cleanup
set_pte_present() is no longer used, directly or indirectly,
so remove it.
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: Xen-devel <xen-devel@lists.xensource.com>
Cc: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: Alok Kataria <akataria@vmware.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Avi Kivity <avi@redhat.com>
LKML-Reference: <1237406613-2929-2-git-send-email-jeremy@goop.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
arch/x86/include/asm/paravirt.h | 15 ---------------
arch/x86/include/asm/pgtable-2level.h | 7 -------
arch/x86/include/asm/pgtable-3level.h | 17 -----------------
arch/x86/include/asm/pgtable.h | 2 --
arch/x86/kernel/kvm.c | 7 -------
arch/x86/kernel/paravirt.c | 1 -
arch/x86/kernel/vmi_32.c | 6 ------
arch/x86/xen/mmu.c | 1 -
8 files changed, 56 deletions(-)
(limited to 'arch/x86/xen/mmu.c')
diff --git a/arch/x86/include/asm/paravirt.h b/arch/x86/include/asm/paravirt.h
index 31fe83b10a4..7727aa8b7dd 100644
--- a/arch/x86/include/asm/paravirt.h
+++ b/arch/x86/include/asm/paravirt.h
@@ -317,8 +317,6 @@ struct pv_mmu_ops {
#if PAGETABLE_LEVELS >= 3
#ifdef CONFIG_X86_PAE
void (*set_pte_atomic)(pte_t *ptep, pte_t pteval);
- void (*set_pte_present)(struct mm_struct *mm, unsigned long addr,
- pte_t *ptep, pte_t pte);
void (*pte_clear)(struct mm_struct *mm, unsigned long addr,
pte_t *ptep);
void (*pmd_clear)(pmd_t *pmdp);
@@ -1365,13 +1363,6 @@ static inline void set_pte_atomic(pte_t *ptep, pte_t pte)
pte.pte, pte.pte >> 32);
}
-static inline void set_pte_present(struct mm_struct *mm, unsigned long addr,
- pte_t *ptep, pte_t pte)
-{
- /* 5 arg words */
- pv_mmu_ops.set_pte_present(mm, addr, ptep, pte);
-}
-
static inline void pte_clear(struct mm_struct *mm, unsigned long addr,
pte_t *ptep)
{
@@ -1388,12 +1379,6 @@ static inline void set_pte_atomic(pte_t *ptep, pte_t pte)
set_pte(ptep, pte);
}
-static inline void set_pte_present(struct mm_struct *mm, unsigned long addr,
- pte_t *ptep, pte_t pte)
-{
- set_pte(ptep, pte);
-}
-
static inline void pte_clear(struct mm_struct *mm, unsigned long addr,
pte_t *ptep)
{
diff --git a/arch/x86/include/asm/pgtable-2level.h b/arch/x86/include/asm/pgtable-2level.h
index c1774ac9da7..2334982b339 100644
--- a/arch/x86/include/asm/pgtable-2level.h
+++ b/arch/x86/include/asm/pgtable-2level.h
@@ -26,13 +26,6 @@ static inline void native_set_pte_atomic(pte_t *ptep, pte_t pte)
native_set_pte(ptep, pte);
}
-static inline void native_set_pte_present(struct mm_struct *mm,
- unsigned long addr,
- pte_t *ptep, pte_t pte)
-{
- native_set_pte(ptep, pte);
-}
-
static inline void native_pmd_clear(pmd_t *pmdp)
{
native_set_pmd(pmdp, __pmd(0));
diff --git a/arch/x86/include/asm/pgtable-3level.h b/arch/x86/include/asm/pgtable-3level.h
index 3f13cdf6115..177b0165ea0 100644
--- a/arch/x86/include/asm/pgtable-3level.h
+++ b/arch/x86/include/asm/pgtable-3level.h
@@ -31,23 +31,6 @@ static inline void native_set_pte(pte_t *ptep, pte_t pte)
ptep->pte_low = pte.pte_low;
}
-/*
- * Since this is only called on user PTEs, and the page fault handler
- * must handle the already racy situation of simultaneous page faults,
- * we are justified in merely clearing the PTE present bit, followed
- * by a set. The ordering here is important.
- */
-static inline void native_set_pte_present(struct mm_struct *mm,
- unsigned long addr,
- pte_t *ptep, pte_t pte)
-{
- ptep->pte_low = 0;
- smp_wmb();
- ptep->pte_high = pte.pte_high;
- smp_wmb();
- ptep->pte_low = pte.pte_low;
-}
-
static inline void native_set_pte_atomic(pte_t *ptep, pte_t pte)
{
set_64bit((unsigned long long *)(ptep), native_pte_val(pte));
diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h
index d0812e155f1..29d96d168bc 100644
--- a/arch/x86/include/asm/pgtable.h
+++ b/arch/x86/include/asm/pgtable.h
@@ -31,8 +31,6 @@ extern struct list_head pgd_list;
#define set_pte(ptep, pte) native_set_pte(ptep, pte)
#define set_pte_at(mm, addr, ptep, pte) native_set_pte_at(mm, addr, ptep, pte)
-#define set_pte_present(mm, addr, ptep, pte) \
- native_set_pte_present(mm, addr, ptep, pte)
#define set_pte_atomic(ptep, pte) \
native_set_pte_atomic(ptep, pte)
diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c
index 478bca986ec..33019ddb56b 100644
--- a/arch/x86/kernel/kvm.c
+++ b/arch/x86/kernel/kvm.c
@@ -138,12 +138,6 @@ static void kvm_set_pte_atomic(pte_t *ptep, pte_t pte)
kvm_mmu_write(ptep, pte_val(pte));
}
-static void kvm_set_pte_present(struct mm_struct *mm, unsigned long addr,
- pte_t *ptep, pte_t pte)
-{
- kvm_mmu_write(ptep, pte_val(pte));
-}
-
static void kvm_pte_clear(struct mm_struct *mm,
unsigned long addr, pte_t *ptep)
{
@@ -220,7 +214,6 @@ static void paravirt_ops_setup(void)
#if PAGETABLE_LEVELS >= 3
#ifdef CONFIG_X86_PAE
pv_mmu_ops.set_pte_atomic = kvm_set_pte_atomic;
- pv_mmu_ops.set_pte_present = kvm_set_pte_present;
pv_mmu_ops.pte_clear = kvm_pte_clear;
pv_mmu_ops.pmd_clear = kvm_pmd_clear;
#endif
diff --git a/arch/x86/kernel/paravirt.c b/arch/x86/kernel/paravirt.c
index 63dd358d8ee..8e45f446488 100644
--- a/arch/x86/kernel/paravirt.c
+++ b/arch/x86/kernel/paravirt.c
@@ -470,7 +470,6 @@ struct pv_mmu_ops pv_mmu_ops = {
#if PAGETABLE_LEVELS >= 3
#ifdef CONFIG_X86_PAE
.set_pte_atomic = native_set_pte_atomic,
- .set_pte_present = native_set_pte_present,
.pte_clear = native_pte_clear,
.pmd_clear = native_pmd_clear,
#endif
diff --git a/arch/x86/kernel/vmi_32.c b/arch/x86/kernel/vmi_32.c
index 2cc4a90e2cb..95deb9f2211 100644
--- a/arch/x86/kernel/vmi_32.c
+++ b/arch/x86/kernel/vmi_32.c
@@ -395,11 +395,6 @@ static void vmi_set_pte_atomic(pte_t *ptep, pte_t pteval)
vmi_ops.update_pte(ptep, VMI_PAGE_PT);
}
-static void vmi_set_pte_present(struct mm_struct *mm, unsigned long addr, pte_t *ptep, pte_t pte)
-{
- vmi_ops.set_pte(pte, ptep, vmi_flags_addr_defer(mm, addr, VMI_PAGE_PT, 1));
-}
-
static void vmi_set_pud(pud_t *pudp, pud_t pudval)
{
/* Um, eww */
@@ -750,7 +745,6 @@ static inline int __init activate_vmi(void)
pv_mmu_ops.set_pmd = vmi_set_pmd;
#ifdef CONFIG_X86_PAE
pv_mmu_ops.set_pte_atomic = vmi_set_pte_atomic;
- pv_mmu_ops.set_pte_present = vmi_set_pte_present;
pv_mmu_ops.set_pud = vmi_set_pud;
pv_mmu_ops.pte_clear = vmi_pte_clear;
pv_mmu_ops.pmd_clear = vmi_pmd_clear;
diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c
index 72f6a76dbfb..db3802fb7b8 100644
--- a/arch/x86/xen/mmu.c
+++ b/arch/x86/xen/mmu.c
@@ -1870,7 +1870,6 @@ const struct pv_mmu_ops xen_mmu_ops __initdata = {
#ifdef CONFIG_X86_PAE
.set_pte_atomic = xen_set_pte_atomic,
- .set_pte_present = xen_set_pte_at,
.pte_clear = xen_pte_clear,
.pmd_clear = xen_pmd_clear,
#endif /* CONFIG_X86_PAE */
--
cgit v1.2.3-70-g09d2