From 56425306517ef28a9b480161cdb96d182172bc1d Mon Sep 17 00:00:00 2001 From: "David S. Miller" Date: Sun, 25 Sep 2005 16:46:57 -0700 Subject: [PATCH] [SPARC64]: Add CONFIG_DEBUG_PAGEALLOC support. The trick is that we do the kernel linear mapping TLB miss starting with an instruction sequence like this: ba,pt %xcc, kvmap_load xor %g2, %g4, %g5 succeeded by an instruction sequence which performs a full page table walk starting at swapper_pg_dir. We first take over the trap table from the firmware. Then, using this constant PTE generation for the linear mapping area above, we build the kernel page tables for the linear mapping. After this is setup, we patch that branch above into a "nop", which will cause TLB misses to fall through to the full page table walk. With this, the page unmapping for CONFIG_DEBUG_PAGEALLOC is trivial. Signed-off-by: David S. Miller --- arch/sparc64/Kconfig.debug | 8 +++ arch/sparc64/kernel/head.S | 6 -- arch/sparc64/kernel/ktlb.S | 33 ++++++++- arch/sparc64/kernel/vmlinux.lds.S | 3 +- arch/sparc64/mm/init.c | 109 +++++++++++++++++++++++++++++- include/asm-sparc64/cacheflush.h | 5 ++ include/asm-sparc64/pgtable.h | 7 +- 7 files changed, 156 insertions(+), 15 deletions(-) diff --git a/arch/sparc64/Kconfig.debug b/arch/sparc64/Kconfig.debug index af0e9411b8..fa06ea0483 100644 --- a/arch/sparc64/Kconfig.debug +++ b/arch/sparc64/Kconfig.debug @@ -33,6 +33,14 @@ config DEBUG_BOOTMEM depends on DEBUG_KERNEL bool "Debug BOOTMEM initialization" +config DEBUG_PAGEALLOC + bool "Page alloc debugging" + depends on DEBUG_KERNEL && !SOFTWARE_SUSPEND + help + Unmap pages from the kernel linear mapping after free_pages(). + This results in a large slowdown, but helps to find certain types + of memory corruptions. + config MCOUNT bool depends on STACK_DEBUG diff --git a/arch/sparc64/kernel/head.S b/arch/sparc64/kernel/head.S index 56af714f5f..ecc748fb9a 100644 --- a/arch/sparc64/kernel/head.S +++ b/arch/sparc64/kernel/head.S @@ -525,12 +525,6 @@ bootup_user_stack_end: #include "ttable.S" #include "systbls.S" - - .align 1024 - .globl swapper_pg_dir -swapper_pg_dir: - .word 0 - #include "ktlb.S" #include "etrap.S" #include "rtrap.S" diff --git a/arch/sparc64/kernel/ktlb.S b/arch/sparc64/kernel/ktlb.S index a591bc0ebc..7796b37f47 100644 --- a/arch/sparc64/kernel/ktlb.S +++ b/arch/sparc64/kernel/ktlb.S @@ -132,9 +132,40 @@ kvmap_do_obp: */ .align 32 kvmap: - brlz,pt %g4, kvmap_load + brgez,pn %g4, kvmap_nonlinear + nop + +#ifdef CONFIG_DEBUG_PAGEALLOC + .globl kvmap_linear_patch +kvmap_linear_patch: +#endif + ba,pt %xcc, kvmap_load xor %g2, %g4, %g5 +#ifdef CONFIG_DEBUG_PAGEALLOC + sethi %hi(swapper_pg_dir), %g5 + or %g5, %lo(swapper_pg_dir), %g5 + sllx %g4, 64 - (PGDIR_SHIFT + PGDIR_BITS), %g6 + srlx %g6, 64 - PAGE_SHIFT, %g6 + andn %g6, 0x3, %g6 + lduw [%g5 + %g6], %g5 + brz,pn %g5, longpath + sllx %g4, 64 - (PMD_SHIFT + PMD_BITS), %g6 + srlx %g6, 64 - PAGE_SHIFT, %g6 + sllx %g5, 11, %g5 + andn %g6, 0x3, %g6 + lduwa [%g5 + %g6] ASI_PHYS_USE_EC, %g5 + brz,pn %g5, longpath + sllx %g4, 64 - PMD_SHIFT, %g6 + srlx %g6, 64 - PAGE_SHIFT, %g6 + sllx %g5, 11, %g5 + andn %g6, 0x7, %g6 + ldxa [%g5 + %g6] ASI_PHYS_USE_EC, %g5 + brz,pn %g5, longpath + nop + ba,a,pt %xcc, kvmap_load +#endif + kvmap_nonlinear: sethi %hi(MODULES_VADDR), %g5 cmp %g4, %g5 diff --git a/arch/sparc64/kernel/vmlinux.lds.S b/arch/sparc64/kernel/vmlinux.lds.S index f47d0be393..2af0cf0a86 100644 --- a/arch/sparc64/kernel/vmlinux.lds.S +++ b/arch/sparc64/kernel/vmlinux.lds.S @@ -9,8 +9,7 @@ ENTRY(_start) jiffies = jiffies_64; SECTIONS { - swapper_pmd_dir = 0x0000000000402000; - empty_pg_dir = 0x0000000000403000; + swapper_low_pmd_dir = 0x0000000000402000; . = 0x4000; .text 0x0000000000404000 : { diff --git a/arch/sparc64/mm/init.c b/arch/sparc64/mm/init.c index cf747372f0..8d72f8a126 100644 --- a/arch/sparc64/mm/init.c +++ b/arch/sparc64/mm/init.c @@ -1332,15 +1332,114 @@ unsigned long __init bootmem_init(unsigned long *pages_avail) return end_pfn; } +#ifdef CONFIG_DEBUG_PAGEALLOC +static unsigned long kernel_map_range(unsigned long pstart, unsigned long pend, pgprot_t prot) +{ + unsigned long vstart = PAGE_OFFSET + pstart; + unsigned long vend = PAGE_OFFSET + pend; + unsigned long alloc_bytes = 0UL; + + if ((vstart & ~PAGE_MASK) || (vend & ~PAGE_MASK)) { + prom_printf("kernel_map: Unaligned sp_banks[%lx:%lx]\n", + vstart, vend); + prom_halt(); + } + + while (vstart < vend) { + unsigned long this_end, paddr = __pa(vstart); + pgd_t *pgd = pgd_offset_k(vstart); + pud_t *pud; + pmd_t *pmd; + pte_t *pte; + + pud = pud_offset(pgd, vstart); + if (pud_none(*pud)) { + pmd_t *new; + + new = __alloc_bootmem(PAGE_SIZE, PAGE_SIZE, PAGE_SIZE); + alloc_bytes += PAGE_SIZE; + pud_populate(&init_mm, pud, new); + } + + pmd = pmd_offset(pud, vstart); + if (!pmd_present(*pmd)) { + pte_t *new; + + new = __alloc_bootmem(PAGE_SIZE, PAGE_SIZE, PAGE_SIZE); + alloc_bytes += PAGE_SIZE; + pmd_populate_kernel(&init_mm, pmd, new); + } + + pte = pte_offset_kernel(pmd, vstart); + this_end = (vstart + PMD_SIZE) & PMD_MASK; + if (this_end > vend) + this_end = vend; + + while (vstart < this_end) { + pte_val(*pte) = (paddr | pgprot_val(prot)); + + vstart += PAGE_SIZE; + paddr += PAGE_SIZE; + pte++; + } + } + + return alloc_bytes; +} + +extern struct linux_mlist_p1275 *prom_ptot_ptr; +extern unsigned int kvmap_linear_patch[1]; + +static void __init kernel_physical_mapping_init(void) +{ + struct linux_mlist_p1275 *p = prom_ptot_ptr; + unsigned long mem_alloced = 0UL; + + while (p) { + unsigned long phys_start, phys_end; + + phys_start = p->start_adr; + phys_end = phys_start + p->num_bytes; + mem_alloced += kernel_map_range(phys_start, phys_end, + PAGE_KERNEL); + + p = p->theres_more; + } + + printk("Allocated %ld bytes for kernel page tables.\n", + mem_alloced); + + kvmap_linear_patch[0] = 0x01000000; /* nop */ + flushi(&kvmap_linear_patch[0]); + + __flush_tlb_all(); +} + +void kernel_map_pages(struct page *page, int numpages, int enable) +{ + unsigned long phys_start = page_to_pfn(page) << PAGE_SHIFT; + unsigned long phys_end = phys_start + (numpages * PAGE_SIZE); + + kernel_map_range(phys_start, phys_end, + (enable ? PAGE_KERNEL : __pgprot(0))); + + /* we should perform an IPI and flush all tlbs, + * but that can deadlock->flush only current cpu. + */ + __flush_tlb_kernel_range(PAGE_OFFSET + phys_start, + PAGE_OFFSET + phys_end); +} +#endif + /* paging_init() sets up the page tables */ extern void cheetah_ecache_flush_init(void); static unsigned long last_valid_pfn; +pgd_t swapper_pg_dir[2048]; void __init paging_init(void) { - extern pmd_t swapper_pmd_dir[1024]; unsigned long end_pfn, pages_avail, shift; unsigned long real_end; @@ -1361,11 +1460,11 @@ void __init paging_init(void) */ init_mm.pgd += ((shift) / (sizeof(pgd_t))); - memset(swapper_pmd_dir, 0, sizeof(swapper_pmd_dir)); + memset(swapper_low_pmd_dir, 0, sizeof(swapper_low_pmd_dir)); /* Now can init the kernel/bad page tables. */ pud_set(pud_offset(&swapper_pg_dir[0], 0), - swapper_pmd_dir + (shift / sizeof(pgd_t))); + swapper_low_pmd_dir + (shift / sizeof(pgd_t))); swapper_pgd_zero = pgd_val(swapper_pg_dir[0]); @@ -1390,6 +1489,10 @@ void __init paging_init(void) pages_avail = 0; last_valid_pfn = end_pfn = bootmem_init(&pages_avail); +#ifdef CONFIG_DEBUG_PAGEALLOC + kernel_physical_mapping_init(); +#endif + { unsigned long zones_size[MAX_NR_ZONES]; unsigned long zholes_size[MAX_NR_ZONES]; diff --git a/include/asm-sparc64/cacheflush.h b/include/asm-sparc64/cacheflush.h index ededd2659e..b3f61659ba 100644 --- a/include/asm-sparc64/cacheflush.h +++ b/include/asm-sparc64/cacheflush.h @@ -66,6 +66,11 @@ extern void flush_ptrace_access(struct vm_area_struct *, struct page *, #define flush_cache_vmap(start, end) do { } while (0) #define flush_cache_vunmap(start, end) do { } while (0) +#ifdef CONFIG_DEBUG_PAGEALLOC +/* internal debugging function */ +void kernel_map_pages(struct page *page, int numpages, int enable); +#endif + #endif /* !__ASSEMBLY__ */ #endif /* _SPARC64_CACHEFLUSH_H */ diff --git a/include/asm-sparc64/pgtable.h b/include/asm-sparc64/pgtable.h index a297f6144f..43cbb089cd 100644 --- a/include/asm-sparc64/pgtable.h +++ b/include/asm-sparc64/pgtable.h @@ -60,13 +60,13 @@ * table can map */ #define PMD_SHIFT (PAGE_SHIFT + (PAGE_SHIFT-3)) -#define PMD_SIZE (1UL << PMD_SHIFT) +#define PMD_SIZE (_AC(1,UL) << PMD_SHIFT) #define PMD_MASK (~(PMD_SIZE-1)) #define PMD_BITS (PAGE_SHIFT - 2) /* PGDIR_SHIFT determines what a third-level page table entry can map */ #define PGDIR_SHIFT (PAGE_SHIFT + (PAGE_SHIFT-3) + PMD_BITS) -#define PGDIR_SIZE (1UL << PGDIR_SHIFT) +#define PGDIR_SIZE (_AC(1,UL) << PGDIR_SHIFT) #define PGDIR_MASK (~(PGDIR_SIZE-1)) #define PGDIR_BITS (PAGE_SHIFT - 2) @@ -336,7 +336,8 @@ static inline void set_pte_at(struct mm_struct *mm, unsigned long addr, pte_t *p #define pte_clear(mm,addr,ptep) \ set_pte_at((mm), (addr), (ptep), __pte(0UL)) -extern pgd_t swapper_pg_dir[1]; +extern pgd_t swapper_pg_dir[2048]; +extern pmd_t swapper_low_pmd_dir[2048]; /* These do nothing with the way I have things setup. */ #define mmu_lockarea(vaddr, len) (vaddr) -- 2.39.5