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[SPARC64]: Fix initrd when net booting.
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By allocating early memory for the firmware page tables, we
can write over the beginning of the initrd image.

So what we do now is:

1) Read in firmware translations table while still on the
   firmware's trap table.
2) Switch to Linux trap table.
3) Init bootmem.
4) Build firmware page tables using __alloc_bootmem().

And this keeps the initrd from being clobbered.

Signed-off-by: David S. Miller <davem@davemloft.net>
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David S. Miller committed Oct 5, 2005
1 parent 782c3fd commit 9ad98c5
Showing 1 changed file with 56 additions and 100 deletions.
156 changes: 56 additions & 100 deletions arch/sparc64/mm/init.c
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Original file line number Diff line number Diff line change
Expand Up @@ -368,6 +368,7 @@ struct linux_prom_translation {
unsigned long data;
};
static struct linux_prom_translation prom_trans[512] __initdata;
static unsigned int prom_trans_ents __initdata;

extern unsigned long prom_boot_page;
extern void prom_remap(unsigned long physpage, unsigned long virtpage, int mmu_ihandle);
Expand All @@ -381,57 +382,7 @@ unsigned long kern_locked_tte_data;
unsigned long prom_pmd_phys __read_mostly;
unsigned int swapper_pgd_zero __read_mostly;

/* Allocate power-of-2 aligned chunks from the end of the
* kernel image. Return physical address.
*/
static inline unsigned long early_alloc_phys(unsigned long size)
{
unsigned long base;

BUILD_BUG_ON(size & (size - 1));

kern_size = (kern_size + (size - 1)) & ~(size - 1);
base = kern_base + kern_size;
kern_size += size;

return base;
}

static inline unsigned long load_phys32(unsigned long pa)
{
unsigned long val;

__asm__ __volatile__("lduwa [%1] %2, %0"
: "=&r" (val)
: "r" (pa), "i" (ASI_PHYS_USE_EC));

return val;
}

static inline unsigned long load_phys64(unsigned long pa)
{
unsigned long val;

__asm__ __volatile__("ldxa [%1] %2, %0"
: "=&r" (val)
: "r" (pa), "i" (ASI_PHYS_USE_EC));

return val;
}

static inline void store_phys32(unsigned long pa, unsigned long val)
{
__asm__ __volatile__("stwa %0, [%1] %2"
: /* no outputs */
: "r" (val), "r" (pa), "i" (ASI_PHYS_USE_EC));
}

static inline void store_phys64(unsigned long pa, unsigned long val)
{
__asm__ __volatile__("stxa %0, [%1] %2"
: /* no outputs */
: "r" (val), "r" (pa), "i" (ASI_PHYS_USE_EC));
}
static pmd_t *prompmd __read_mostly;

#define BASE_PAGE_SIZE 8192

Expand All @@ -441,34 +392,28 @@ static inline void store_phys64(unsigned long pa, unsigned long val)
*/
unsigned long prom_virt_to_phys(unsigned long promva, int *error)
{
unsigned long pmd_phys = (prom_pmd_phys +
((promva >> 23) & 0x7ff) * sizeof(pmd_t));
unsigned long pte_phys;
pmd_t pmd_ent;
pte_t pte_ent;
pmd_t *pmdp = prompmd + ((promva >> 23) & 0x7ff);
pte_t *ptep;
unsigned long base;

pmd_val(pmd_ent) = load_phys32(pmd_phys);
if (pmd_none(pmd_ent)) {
if (pmd_none(*pmdp)) {
if (error)
*error = 1;
return 0;
}

pte_phys = (unsigned long)pmd_val(pmd_ent) << 11UL;
pte_phys += ((promva >> 13) & 0x3ff) * sizeof(pte_t);
pte_val(pte_ent) = load_phys64(pte_phys);
if (!pte_present(pte_ent)) {
ptep = (pte_t *)__pmd_page(*pmdp) + ((promva >> 13) & 0x3ff);
if (!pte_present(*ptep)) {
if (error)
*error = 1;
return 0;
}
if (error) {
*error = 0;
return pte_val(pte_ent);
return pte_val(*ptep);
}
base = pte_val(pte_ent) & _PAGE_PADDR;
return (base + (promva & (BASE_PAGE_SIZE - 1)));
base = pte_val(*ptep) & _PAGE_PADDR;

return base + (promva & (BASE_PAGE_SIZE - 1));
}

/* The obp translations are saved based on 8k pagesize, since obp can
Expand All @@ -481,33 +426,29 @@ static void __init build_obp_range(unsigned long start, unsigned long end, unsig
unsigned long vaddr;

for (vaddr = start; vaddr < end; vaddr += BASE_PAGE_SIZE) {
unsigned long val, pte_phys, pmd_phys;
pmd_t pmd_ent;
int i;

pmd_phys = (prom_pmd_phys +
(((vaddr >> 23) & 0x7ff) * sizeof(pmd_t)));
pmd_val(pmd_ent) = load_phys32(pmd_phys);
if (pmd_none(pmd_ent)) {
pte_phys = early_alloc_phys(BASE_PAGE_SIZE);

for (i = 0; i < BASE_PAGE_SIZE / sizeof(pte_t); i++)
store_phys64(pte_phys+i*sizeof(pte_t),0);
unsigned long val;
pmd_t *pmd;
pte_t *pte;

pmd_val(pmd_ent) = pte_phys >> 11UL;
store_phys32(pmd_phys, pmd_val(pmd_ent));
pmd = prompmd + ((vaddr >> 23) & 0x7ff);
if (pmd_none(*pmd)) {
pte = __alloc_bootmem(BASE_PAGE_SIZE, BASE_PAGE_SIZE,
PAGE_SIZE);
if (!pte)
prom_halt();
memset(pte, 0, BASE_PAGE_SIZE);
pmd_set(pmd, pte);
}

pte_phys = (unsigned long)pmd_val(pmd_ent) << 11UL;
pte_phys += (((vaddr >> 13) & 0x3ff) * sizeof(pte_t));
pte = (pte_t *) __pmd_page(*pmd) + ((vaddr >> 13) & 0x3ff);

val = data;

/* Clear diag TTE bits. */
if (tlb_type == spitfire)
val &= ~0x0003fe0000000000UL;

store_phys64(pte_phys, val | _PAGE_MODIFIED);
set_pte_at(&init_mm, vaddr, pte,
__pte(val | _PAGE_MODIFIED));

data += BASE_PAGE_SIZE;
}
Expand All @@ -520,13 +461,17 @@ static inline int in_obp_range(unsigned long vaddr)
}

#define OBP_PMD_SIZE 2048
static void __init build_obp_pgtable(int prom_trans_ents)
static void __init build_obp_pgtable(void)
{
unsigned long i;

prom_pmd_phys = early_alloc_phys(OBP_PMD_SIZE);
for (i = 0; i < OBP_PMD_SIZE; i += 4)
store_phys32(prom_pmd_phys + i, 0);
prompmd = __alloc_bootmem(OBP_PMD_SIZE, OBP_PMD_SIZE, PAGE_SIZE);
if (!prompmd)
prom_halt();

memset(prompmd, 0, OBP_PMD_SIZE);

prom_pmd_phys = __pa(prompmd);

for (i = 0; i < prom_trans_ents; i++) {
unsigned long start, end;
Expand All @@ -546,7 +491,7 @@ static void __init build_obp_pgtable(int prom_trans_ents)
/* Read OBP translations property into 'prom_trans[]'.
* Return the number of entries.
*/
static int __init read_obp_translations(void)
static void __init read_obp_translations(void)
{
int n, node;

Expand All @@ -567,8 +512,10 @@ static int __init read_obp_translations(void)
prom_printf("prom_mappings: Couldn't get property.\n");
prom_halt();
}

n = n / sizeof(struct linux_prom_translation);
return n;

prom_trans_ents = n;
}

static void __init remap_kernel(void)
Expand Down Expand Up @@ -605,19 +552,21 @@ static void __init remap_kernel(void)
}
}

static void __init inherit_prom_mappings(void)
{
int n;

n = read_obp_translations();
build_obp_pgtable(n);
static void __init inherit_prom_mappings_pre(void)
{
read_obp_translations();

/* Now fixup OBP's idea about where we really are mapped. */
prom_printf("Remapping the kernel... ");
remap_kernel();

prom_printf("done.\n");
}

static void __init inherit_prom_mappings_post(void)
{
build_obp_pgtable();
register_prom_callbacks();
}

Expand Down Expand Up @@ -1570,8 +1519,7 @@ void __init paging_init(void)

swapper_pgd_zero = pgd_val(swapper_pg_dir[0]);

/* Inherit non-locked OBP mappings. */
inherit_prom_mappings();
inherit_prom_mappings_pre();

/* Ok, we can use our TLB miss and window trap handlers safely.
* We need to do a quick peek here to see if we are on StarFire
Expand All @@ -1582,15 +1530,23 @@ void __init paging_init(void)
extern void setup_tba(int);
setup_tba(this_is_starfire);
}

inherit_locked_prom_mappings(1);

__flush_tlb_all();

/* Everything from this point forward, until we are done with
* inherit_prom_mappings_post(), must complete successfully
* without calling into the firmware. The firwmare page tables
* have not been built, but we are running on the Linux kernel's
* trap table.
*/

/* Setup bootmem... */
pages_avail = 0;
last_valid_pfn = end_pfn = bootmem_init(&pages_avail);

inherit_prom_mappings_post();

inherit_locked_prom_mappings(1);

#ifdef CONFIG_DEBUG_PAGEALLOC
kernel_physical_mapping_init();
#endif
Expand Down

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