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Date: Wed, 10 Oct 2007 16:44:36 +0200
From: Johannes Weiner <hannes-kernel@...urebad.de>
To: Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: [PATCH 2/2] i386 memory initialization cleanup
i386 memory init cleanup
This patch improves code readability in the i386 memory initialization code
by refactoring, removal of needless casts, fixing of line width exceedings,
macro->inline function replacement, some comments and indentation correction.
Signed-off-by: Johannes Weiner <hannes-kernel@...urebad.de>
---
Note: Functionality was modified in set_kernel_exec(): It bails out if
lookup_address() fails to prevent a NULL pointer dereference.
arch/i386/mm/init.c | 211 +++++++++++++++++++++++++++------------------------
1 files changed, 113 insertions(+), 98 deletions(-)
diff --git a/arch/i386/mm/init.c b/arch/i386/mm/init.c
index dc3c03f..15a109e 100644
--- a/arch/i386/mm/init.c
+++ b/arch/i386/mm/init.c
@@ -64,13 +64,12 @@ static pmd_t * __init one_md_table_init(pgd_t *pgd)
#ifdef CONFIG_X86_PAE
if (!(pgd_val(*pgd) & _PAGE_PRESENT)) {
- pmd_table = (pmd_t *) alloc_bootmem_low_pages(PAGE_SIZE);
+ pmd_table = alloc_bootmem_low_pages(PAGE_SIZE);
paravirt_alloc_pd(__pa(pmd_table) >> PAGE_SHIFT);
set_pgd(pgd, __pgd(__pa(pmd_table) | _PAGE_PRESENT));
pud = pud_offset(pgd, 0);
- if (pmd_table != pmd_offset(pud, 0))
- BUG();
+ BUG_ON(pmd_table != pmd_offset(pud, 0));
}
#endif
pud = pud_offset(pgd, 0);
@@ -85,7 +84,7 @@ static pmd_t * __init one_md_table_init(pgd_t *pgd)
static pte_t * __init one_page_table_init(pmd_t *pmd)
{
if (!(pmd_val(*pmd) & _PAGE_PRESENT)) {
- pte_t *page_table = (pte_t *) alloc_bootmem_low_pages(PAGE_SIZE);
+ pte_t *page_table = alloc_bootmem_low_pages(PAGE_SIZE);
paravirt_alloc_pt(&init_mm, __pa(page_table) >> PAGE_SHIFT);
set_pmd(pmd, __pmd(__pa(page_table) | _PAGE_TABLE));
@@ -106,27 +105,25 @@ static pte_t * __init one_page_table_init(pmd_t *pmd)
* so we can cache the place of the first one and move around without
* checking the pgd every time.
*/
-static void __init page_table_range_init (unsigned long start, unsigned long end, pgd_t *pgd_base)
-{
- pgd_t *pgd;
- pmd_t *pmd;
- int pgd_idx, pmd_idx;
- unsigned long vaddr;
-
- vaddr = start;
- pgd_idx = pgd_index(vaddr);
- pmd_idx = pmd_index(vaddr);
- pgd = pgd_base + pgd_idx;
-
- for ( ; (pgd_idx < PTRS_PER_PGD) && (vaddr != end); pgd++, pgd_idx++) {
- pmd = one_md_table_init(pgd);
- pmd = pmd + pmd_index(vaddr);
- for (; (pmd_idx < PTRS_PER_PMD) && (vaddr != end); pmd++, pmd_idx++) {
- one_page_table_init(pmd);
+static void __init page_table_range_init(unsigned long start,
+ unsigned long end, pgd_t *pgd_base)
+{
+ unsigned long vaddr = start;
+ int pgd_idx = pgd_index(start);
+ int pmd_idx = pmd_index(start);
+ pgd_t *pgd = pgd_base + pgd_idx;
+ while (pgd_idx < PTRS_PER_PGD && vaddr != end) {
+ pmd_t *pmd = one_md_table_init(pgd) + pmd_index(vaddr);
+ while (pmd_idx < PTRS_PER_PMD && vaddr != end) {
+ one_page_table_init(pmd);
vaddr += PMD_SIZE;
+ pmd++;
+ pmd_idx++;
}
pmd_idx = 0;
+ pgd++;
+ pgd_idx++;
}
}
@@ -137,6 +134,43 @@ static inline int is_kernel_text(unsigned long addr)
return 0;
}
+static void __init kernel_pmd_init(pmd_t *pmd, unsigned long *pfnp)
+{
+ unsigned long pfn = *pfnp;
+ unsigned int addr = pfn * PAGE_SIZE + PAGE_OFFSET;
+
+ /* Map with big pages if possible, otherwise create normal
+ * page tables. */
+ if (cpu_has_pse) {
+ unsigned int addr2 = (pfn + PTRS_PER_PTE - 1) * PAGE_SIZE +
+ PAGE_OFFSET + PAGE_SIZE - 1;
+
+ if (is_kernel_text(addr) || is_kernel_text(addr2))
+ set_pmd(pmd, pfn_pmd(pfn, PAGE_KERNEL_LARGE_EXEC));
+ else
+ set_pmd(pmd, pfn_pmd(pfn, PAGE_KERNEL_LARGE));
+
+ pfn += PTRS_PER_PTE;
+ } else {
+ int pte_ofs = 0;
+ pte_t *pte = one_page_table_init(pmd);
+
+ while (pte_ofs < PTRS_PER_PTE && pfn < max_low_pfn) {
+ if (is_kernel_text(addr))
+ set_pte(pte, pfn_pte(pfn, PAGE_KERNEL_EXEC));
+ else
+ set_pte(pte, pfn_pte(pfn, PAGE_KERNEL));
+
+ pte++;
+ pte_ofs++;
+ pfn++;
+ addr += PAGE_SIZE;
+ }
+ }
+
+ *pfnp = pfn;
+}
+
/*
* This maps the physical memory to kernel virtual address space, a total
* of max_low_pfn pages, by creating page tables starting from address
@@ -144,45 +178,25 @@ static inline int is_kernel_text(unsigned long addr)
*/
static void __init kernel_physical_mapping_init(pgd_t *pgd_base)
{
- unsigned long pfn;
- pgd_t *pgd;
- pmd_t *pmd;
- pte_t *pte;
- int pgd_idx, pmd_idx, pte_ofs;
+ unsigned long pfn = 0;
+ int pgd_idx = pgd_index(PAGE_OFFSET);
+ pgd_t *pgd = pgd_base + pgd_idx;
- pgd_idx = pgd_index(PAGE_OFFSET);
- pgd = pgd_base + pgd_idx;
- pfn = 0;
+ while (pgd_idx < PTRS_PER_PGD) {
+ int pmd_idx = 0;
+ pmd_t *pmd = one_md_table_init(pgd);
- for (; pgd_idx < PTRS_PER_PGD; pgd++, pgd_idx++) {
- pmd = one_md_table_init(pgd);
if (pfn >= max_low_pfn)
continue;
- for (pmd_idx = 0; pmd_idx < PTRS_PER_PMD && pfn < max_low_pfn; pmd++, pmd_idx++) {
- unsigned int address = pfn * PAGE_SIZE + PAGE_OFFSET;
-
- /* Map with big pages if possible, otherwise create normal page tables. */
- if (cpu_has_pse) {
- unsigned int address2 = (pfn + PTRS_PER_PTE - 1) * PAGE_SIZE + PAGE_OFFSET + PAGE_SIZE-1;
- if (is_kernel_text(address) || is_kernel_text(address2))
- set_pmd(pmd, pfn_pmd(pfn, PAGE_KERNEL_LARGE_EXEC));
- else
- set_pmd(pmd, pfn_pmd(pfn, PAGE_KERNEL_LARGE));
-
- pfn += PTRS_PER_PTE;
- } else {
- pte = one_page_table_init(pmd);
-
- for (pte_ofs = 0;
- pte_ofs < PTRS_PER_PTE && pfn < max_low_pfn;
- pte++, pfn++, pte_ofs++, address += PAGE_SIZE) {
- if (is_kernel_text(address))
- set_pte(pte, pfn_pte(pfn, PAGE_KERNEL_EXEC));
- else
- set_pte(pte, pfn_pte(pfn, PAGE_KERNEL));
- }
- }
+
+ while (pmd_idx < PTRS_PER_PMD && pfn < max_low_pfn) {
+ kernel_pmd_init(pmd, &pfn);
+ pmd++;
+ pmd_idx++;
}
+
+ pgd++;
+ pgd_idx++;
}
}
@@ -236,36 +250,30 @@ int page_is_ram(unsigned long pagenr)
pte_t *kmap_pte;
pgprot_t kmap_prot;
-#define kmap_get_fixmap_pte(vaddr) \
- pte_offset_kernel(pmd_offset(pud_offset(pgd_offset_k(vaddr), vaddr), (vaddr)), (vaddr))
+static inline pte_t kmap_get_pte(pgd_t *pgd, unsigned long addr)
+{
+ pud_t *pud = pud_offset(pgd, addr);
+ pmd_t *pmd = pmd_offset(pud, addr);
+
+ return pte_offset_kernel(pmd, addr);
+}
static void __init kmap_init(void)
{
- unsigned long kmap_vstart;
+ unsigned long kmap_vstart = __fix_to_virt(FIX_KMAP_BEGIN);
/* cache the first kmap pte */
- kmap_vstart = __fix_to_virt(FIX_KMAP_BEGIN);
- kmap_pte = kmap_get_fixmap_pte(kmap_vstart);
-
+ kmap_pte = kmap_get_fixmap_pte(pgd_offset_k(kmap_vstart), kmap_vstart);
kmap_prot = PAGE_KERNEL;
}
static void __init permanent_kmaps_init(pgd_t *pgd_base)
{
- pgd_t *pgd;
- pud_t *pud;
- pmd_t *pmd;
- pte_t *pte;
- unsigned long vaddr;
-
- vaddr = PKMAP_BASE;
- page_table_range_init(vaddr, vaddr + PAGE_SIZE*LAST_PKMAP, pgd_base);
-
- pgd = swapper_pg_dir + pgd_index(vaddr);
- pud = pud_offset(pgd, vaddr);
- pmd = pmd_offset(pud, vaddr);
- pte = pte_offset_kernel(pmd, vaddr);
- pkmap_page_table = pte;
+ page_table_range_init(PKMAP_BASE,
+ PKMAP_BASE + PAGE_SIZE * LAST_PKMAP,
+ pgd_base);
+ pkmap_page_table = kmap_get_pte(swapper_pg_dir + pgd_index(PKMAP_BASE),
+ PKMAP_BASE);
}
static void __meminit free_new_highpage(struct page *page)
@@ -284,7 +292,8 @@ void __init add_one_highpage_init(struct page *page, int pfn, int bad_ppro)
SetPageReserved(page);
}
-static int __meminit add_one_highpage_hotplug(struct page *page, unsigned long pfn)
+static int __meminit add_one_highpage_hotplug(struct page *page,
+ unsigned long pfn)
{
free_new_highpage(page);
totalram_pages++;
@@ -527,16 +536,18 @@ static void __init set_nx(void)
int __init set_kernel_exec(unsigned long vaddr, int enable)
{
pte_t *pte;
- int ret = 1;
+ int prev;
if (!nx_enabled)
- goto out;
+ return 1;
pte = lookup_address(vaddr);
- BUG_ON(!pte);
+ if (!pte) {
+ BUG();
+ return 1;
+ }
- if (!pte_exec_kernel(*pte))
- ret = 0;
+ prev = pte_exec_kernel(*pte);
if (enable)
pte->pte_high &= ~(1 << (_PAGE_BIT_NX - 32));
@@ -544,11 +555,11 @@ int __init set_kernel_exec(unsigned long vaddr, int enable)
pte->pte_high |= 1 << (_PAGE_BIT_NX - 32);
pte_update_defer(&init_mm, vaddr, pte);
__flush_tlb_all();
-out:
- return ret;
+
+ return prev;
}
-#endif
+#endif /* CONFIG_X86_PAE */
/*
* paging_init() sets up the page tables - note that the first 8MB are
@@ -591,7 +602,8 @@ void __init paging_init(void)
static void __init test_wp_bit(void)
{
- printk("Checking if this processor honours the WP bit even in supervisor mode... ");
+ printk("Checking if this processor honours the WP bit "
+ "even in supervisor mode... ");
/* Any page-aligned address will do, the test is non-destructive */
__set_fixmap(FIX_WP_TEST, __pa(&swapper_pg_dir), PAGE_READONLY);
@@ -601,7 +613,8 @@ static void __init test_wp_bit(void)
if (!boot_cpu_data.wp_works_ok) {
printk("No.\n");
#ifdef CONFIG_X86_WP_WORKS_OK
- panic("This kernel doesn't support CPU's with broken WP. Recompile it for a 386!");
+ panic("This kernel doesn't support CPU's with broken WP. "
+ "Recompile it for a 386!");
#endif
} else {
printk("Ok.\n");
@@ -626,9 +639,11 @@ void __init mem_init(void)
#ifdef CONFIG_HIGHMEM
/* check that fixmap and pkmap do not overlap */
if (PKMAP_BASE+LAST_PKMAP*PAGE_SIZE >= FIXADDR_START) {
- printk(KERN_ERR "fixmap and kmap areas overlap - this will crash\n");
+ printk(KERN_ERR "fixmap and kmap areas overlap "
+ "- this will crash\n");
printk(KERN_ERR "pkstart: %lxh pkend: %lxh fixstart %lxh\n",
- PKMAP_BASE, PKMAP_BASE+LAST_PKMAP*PAGE_SIZE, FIXADDR_START);
+ PKMAP_BASE, PKMAP_BASE+LAST_PKMAP*PAGE_SIZE,
+ FIXADDR_START);
BUG();
}
#endif
@@ -654,15 +669,15 @@ void __init mem_init(void)
kclist_add(&kcore_vmalloc, (void *)VMALLOC_START,
VMALLOC_END-VMALLOC_START);
- printk(KERN_INFO "Memory: %luk/%luk available (%dk kernel code, %dk reserved, %dk data, %dk init, %ldk highmem)\n",
- (unsigned long) nr_free_pages() << (PAGE_SHIFT-10),
- num_physpages << (PAGE_SHIFT-10),
- codesize >> 10,
- reservedpages << (PAGE_SHIFT-10),
- datasize >> 10,
- initsize >> 10,
- (unsigned long) (totalhigh_pages << (PAGE_SHIFT-10))
- );
+ printk(KERN_INFO "Memory: %luk/%luk available (%dk kernel code, "
+ "%dk reserved, %dk data, %dk init, %ldk highmem)\n",
+ (unsigned long) nr_free_pages() << (PAGE_SHIFT-10),
+ num_physpages << (PAGE_SHIFT-10),
+ codesize >> 10,
+ reservedpages << (PAGE_SHIFT-10),
+ datasize >> 10,
+ initsize >> 10,
+ (unsigned long) (totalhigh_pages << (PAGE_SHIFT-10)));
#if 1 /* double-sanity-check paranoia */
printk("virtual kernel memory layout:\n"
@@ -826,7 +841,7 @@ void mark_rodata_ro(void)
*/
global_flush_tlb();
}
-#endif
+#endif /* CONFIG_DEBUG_RODATA */
void free_init_pages(char *what, unsigned long begin, unsigned long end)
{
-
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