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List: linux-mm
Subject: [patch 2/2] clean up types in pageattr code
From: Dave Hansen <haveblue () us ! ibm ! com>
Date: 2004-08-25 19:06:15
Message-ID: E1C0368-0008AG-00 () kernel ! beaverton ! ibm ! com
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Here's another one that started off chasing an "unsigned long" passed to __pa()
in lookup_adddress(). It's kinda like pulling a loose thread on a sweater.
A couple of functions in arch/i386/mm/pageattr.c pass around virtual addresses
as "unsigned long"s and pass them to __pa(). However, only lookup_address()
even gets close to doing any arithmetic on them.
I have the feeling these types were all cascaded because do_page_fault() keeps
the faulting address in an unsigned long and calls lookup_address(). But,
do_page_fault() really is the oddball here because it does so much arithmetic
on that address. So, push the cast in to there.
split_large_page() also gets some renamed variables. Can I just point out
that I'd support any regulation to forcefully remove the keyboards from anyone
who declares 2 variables in the same function called address and addr?
changes to split_large_page():
- rename the variables to more descriptive things than addr
- save some shifts by storing things in pfns to begin with.
- use __get_free_pages() instead of calling alloc_pages() directly
- return virt_to_page() instead of keeping the struct page around
(this effectively does a page_to_virt() in __get_free_pages(), and a
virt_to_page() later on, but this looks a lot nicer, and it't not any
kind of hot path to begin with)
One nice end result is that set_kernel_exec() can take a void* like it wants to
naturally and avoid some casts.
This patch depends on the unsigned long casts for the p*_index() functions
patch that I just sent.
Signed-off-by: Dave Hansen <haveblue@us.ibm.com>
---
memhotplug-dave/arch/i386/kernel/smpboot.c | 4 +-
memhotplug-dave/arch/i386/mm/fault.c | 2 -
memhotplug-dave/arch/i386/mm/init.c | 2 -
memhotplug-dave/arch/i386/mm/pageattr.c | 41 +++++++++++++++--------------
memhotplug-dave/include/asm-i386/pgtable.h | 6 ++--
5 files changed, 29 insertions(+), 26 deletions(-)
diff -puN arch/i386/mm/fault.c~AA1-lookup_address-cousins-types arch/i386/mm/fault.c
--- memhotplug/arch/i386/mm/fault.c~AA1-lookup_address-cousins-types 2004-08-25 \
11:53:58.000000000 -0700
+++ memhotplug-dave/arch/i386/mm/fault.c 2004-08-25 11:53:58.000000000 -0700
@@ -442,7 +442,7 @@ no_context:
#ifdef CONFIG_X86_PAE
if (error_code & 16) {
- pte_t *pte = lookup_address(address);
+ pte_t *pte = lookup_address((void *)address);
if (pte && pte_present(*pte) && !pte_exec_kernel(*pte))
printk(KERN_CRIT "kernel tried to execute NX-protected page - exploit attempt? \
(uid: %d)\n", current->uid);
diff -puN arch/i386/mm/pgtable.c~AA1-lookup_address-cousins-types \
arch/i386/mm/pgtable.c
diff -puN arch/i386/mm/init.c~AA1-lookup_address-cousins-types arch/i386/mm/init.c
--- memhotplug/arch/i386/mm/init.c~AA1-lookup_address-cousins-types 2004-08-25 \
11:53:58.000000000 -0700
+++ memhotplug-dave/arch/i386/mm/init.c 2004-08-25 11:53:58.000000000 -0700
@@ -478,7 +478,7 @@ static void __init set_nx(void)
* Enables/disables executability of a given kernel page and
* returns the previous setting.
*/
-int __init set_kernel_exec(unsigned long vaddr, int enable)
+int __init set_kernel_exec(void *vaddr, int enable)
{
pte_t *pte;
int ret = 1;
diff -puN arch/i386/mm/pageattr.c~AA1-lookup_address-cousins-types \
arch/i386/mm/pageattr.c
--- memhotplug/arch/i386/mm/pageattr.c~AA1-lookup_address-cousins-types 2004-08-25 \
11:53:58.000000000 -0700
+++ memhotplug-dave/arch/i386/mm/pageattr.c 2004-08-25 11:53:58.000000000 -0700
@@ -17,7 +17,7 @@ static spinlock_t cpa_lock = SPIN_LOCK_U
static struct list_head df_list = LIST_HEAD_INIT(df_list);
-pte_t *lookup_address(unsigned long address)
+pte_t *lookup_address(void *address)
{
pgd_t *pgd = pgd_offset_k(address);
pmd_t *pmd;
@@ -31,27 +31,30 @@ pte_t *lookup_address(unsigned long addr
return pte_offset_kernel(pmd, address);
}
-static struct page *split_large_page(unsigned long address, pgprot_t prot)
+static struct page *split_large_page(void *start_vaddr, pgprot_t prot)
{
- int i;
- unsigned long addr;
- struct page *base;
- pte_t *pbase;
+ int i;
+ unsigned long start_pfn;
+ unsigned long small_page_pfn;
+ pte_t *pte_base;
spin_unlock_irq(&cpa_lock);
- base = alloc_pages(GFP_KERNEL, 0);
+ pte_base = (pte_t *)__get_free_pages(GFP_KERNEL, 0);
spin_lock_irq(&cpa_lock);
- if (!base)
+ if (!pte_base)
return NULL;
- address = __pa(address);
- addr = address & LARGE_PAGE_MASK;
- pbase = (pte_t *)page_address(base);
- for (i = 0; i < PTRS_PER_PTE; i++, addr += PAGE_SIZE) {
- pbase[i] = pfn_pte(addr >> PAGE_SHIFT,
- addr == address ? prot : PAGE_KERNEL);
+ start_pfn = __pa(start_vaddr) >> PAGE_SHIFT;
+ small_page_pfn = (start_pfn & (LARGE_PAGE_MASK >> PAGE_SHIFT));
+ for (i = 0; i < PTRS_PER_PTE; i++, small_page_pfn++) {
+ pgprot_t page_prot = PAGE_KERNEL;
+
+ if (small_page_pfn == start_pfn)
+ page_prot = prot;
+
+ pte_base[i] = pfn_pte(small_page_pfn, page_prot);
}
- return base;
+ return virt_to_page(pte_base);
}
static void flush_kernel_map(void *dummy)
@@ -65,7 +68,7 @@ static void flush_kernel_map(void *dummy
__flush_tlb_all();
}
-static void set_pmd_pte(pte_t *kpte, unsigned long address, pte_t pte)
+static void set_pmd_pte(pte_t *kpte, void *address, pte_t pte)
{
struct page *page;
unsigned long flags;
@@ -89,7 +92,7 @@ static void set_pmd_pte(pte_t *kpte, uns
* No more special protections in this 2/4MB area - revert to a
* large page again.
*/
-static inline void revert_page(struct page *kpte_page, unsigned long address)
+static inline void revert_page(struct page *kpte_page, void *address)
{
pte_t *linear = (pte_t *)
pmd_offset(pgd_offset(&init_mm, address), address);
@@ -102,14 +105,14 @@ static int
__change_page_attr(struct page *page, pgprot_t prot)
{
pte_t *kpte;
- unsigned long address;
+ void *address;
struct page *kpte_page;
#ifdef CONFIG_HIGHMEM
if (page >= highmem_start_page)
BUG();
#endif
- address = (unsigned long)page_address(page);
+ address = page_address(page);
kpte = lookup_address(address);
if (!kpte)
diff -puN arch/x86_64/kernel/early_printk.c~AA1-lookup_address-cousins-types \
arch/x86_64/kernel/early_printk.c
diff -L include/linux/nonlinear.h -puN /dev/null /dev/null
diff -puN include/asm-i386/pgtable.h~AA1-lookup_address-cousins-types \
include/asm-i386/pgtable.h
--- memhotplug/include/asm-i386/pgtable.h~AA1-lookup_address-cousins-types 2004-08-25 \
11:53:58.000000000 -0700
+++ memhotplug-dave/include/asm-i386/pgtable.h 2004-08-25 11:53:58.000000000 -0700
@@ -350,7 +350,7 @@ static inline pte_t pte_modify(pte_t pte
* NOTE: the return type is pte_t but if the pmd is PSE then we return it
* as a pte too.
*/
-extern pte_t *lookup_address(unsigned long address);
+extern pte_t *lookup_address(void *address);
/*
* Make a given kernel text page executable/non-executable.
@@ -359,9 +359,9 @@ extern pte_t *lookup_address(unsigned lo
* NOTE: this is an __init function for security reasons.
*/
#ifdef CONFIG_X86_PAE
- extern int set_kernel_exec(unsigned long vaddr, int enable);
+ extern int set_kernel_exec(void *vaddr, int enable);
#else
- static inline int set_kernel_exec(unsigned long vaddr, int enable) { return 0;}
+ static inline int set_kernel_exec(void *vaddr, int enable) { return 0;}
#endif
#if defined(CONFIG_HIGHPTE)
diff -puN include/asm-i386/page.h~AA1-lookup_address-cousins-types \
include/asm-i386/page.h
diff -puN mm/slab.c~AA1-lookup_address-cousins-types mm/slab.c
diff -L mm/nonlinear.c -puN /dev/null /dev/null
diff -L mm/memory_hotplug.c -puN /dev/null /dev/null
diff -puN arch/i386/kernel/sysenter.c~AA1-lookup_address-cousins-types \
arch/i386/kernel/sysenter.c
diff -puN arch/i386/kernel/smpboot.c~AA1-lookup_address-cousins-types \
arch/i386/kernel/smpboot.c
--- memhotplug/arch/i386/kernel/smpboot.c~AA1-lookup_address-cousins-types 2004-08-25 \
11:53:58.000000000 -0700
+++ memhotplug-dave/arch/i386/kernel/smpboot.c 2004-08-25 11:53:58.000000000 -0700
@@ -122,7 +122,7 @@ void __init smp_alloc_memory(void)
/*
* Make the SMP trampoline executable:
*/
- trampoline_exec = set_kernel_exec((unsigned long)trampoline_base, 1);
+ trampoline_exec = set_kernel_exec(trampoline_base, 1);
}
/*
@@ -1249,7 +1249,7 @@ void __init smp_cpus_done(unsigned int m
/*
* Disable executability of the SMP trampoline:
*/
- set_kernel_exec((unsigned long)trampoline_base, trampoline_exec);
+ set_kernel_exec(trampoline_base, trampoline_exec);
}
void __init smp_intr_init(void)
_
--
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