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Commit 392c3822 authored by Paul Mundt's avatar Paul Mundt
Browse files

sh64: Tidy up and consolidate the TLB miss fast path. 



This unifies the fast-path TLB miss handler, allowing for further cleanup
and eventual utilization of a shared _32/_64 handler.

Signed-off-by: default avatarPaul Mundt <lethal@linux-sh.org>
parent 2ec08e14

arch/sh/mm/tlbex_64.c

+15 −92
Original line number Diff line number Diff line
@@ -33,76 +33,32 @@ 
#include <linux/mm.h>

#include <linux/smp.h>

#include <linux/interrupt.h>

#include <linux/kprobes.h>

#include <asm/tlb.h>

#include <asm/io.h>

#include <asm/uaccess.h>

#include <asm/pgalloc.h>

#include <asm/mmu_context.h>



static int handle_vmalloc_fault(struct mm_struct *mm,

				unsigned long protection_flags,

static int handle_tlbmiss(unsigned long long protection_flags,

			  unsigned long address)

{

	pgd_t *dir;

	pgd_t *pgd;

	pud_t *pud;

	pmd_t *pmd;

	pte_t *pte;

	pte_t entry;



	dir = pgd_offset_k(address);



	pud = pud_offset(dir, address);

	if (pud_none_or_clear_bad(pud))

		return 1;



	pmd = pmd_offset(pud, address);

	if (pmd_none_or_clear_bad(pmd))

		return 1;



	pte = pte_offset_kernel(pmd, address);

	entry = *pte;



	if (pte_none(entry) || !pte_present(entry))

		return 1;

	if ((pte_val(entry) & protection_flags) != protection_flags)

	if (is_vmalloc_addr((void *)address)) {

		pgd = pgd_offset_k(address);

	} else {

		if (unlikely(address >= TASK_SIZE || !current->mm))

			return 1;



	update_mmu_cache(NULL, address, pte);



	return 0;

		pgd = pgd_offset(current->mm, address);

	}



static int handle_tlbmiss(struct mm_struct *mm,

			  unsigned long long protection_flags,

			  unsigned long address)

{

	pgd_t *dir;

	pud_t *pud;

	pmd_t *pmd;

	pte_t *pte;

	pte_t entry;



	/* NB. The PGD currently only contains a single entry - there is no

	   page table tree stored for the top half of the address space since

	   virtual pages in that region should never be mapped in user mode.

	   (In kernel mode, the only things in that region are the 512Mb super

	   page (locked in), and vmalloc (modules) +  I/O device pages (handled

	   by handle_vmalloc_fault), so no PGD for the upper half is required

	   by kernel mode either).



	   See how mm->pgd is allocated and initialised in pgd_alloc to see why

	   the next test is necessary.  - RPC */

	if (address >= (unsigned long) TASK_SIZE)

		/* upper half - never has page table entries. */

		return 1;



	dir = pgd_offset(mm, address);

	if (pgd_none(*dir) || !pgd_present(*dir))

		return 1;

	if (!pgd_present(*dir))

		return 1;



	pud = pud_offset(dir, address);

	pud = pud_offset(pgd, address);

	if (pud_none(*pud) || !pud_present(*pud))

		return 1;
@@ -112,7 +68,6 @@ static int handle_tlbmiss(struct mm_struct *mm, 


	pte = pte_offset_kernel(pmd, address);

	entry = *pte;



	if (pte_none(entry) || !pte_present(entry))

		return 1;
@@ -146,9 +101,6 @@ struct expevt_lookup { 
#define PRX (1<<7)

#define PRR (1<<6)



#define DIRTY (_PAGE_DIRTY | _PAGE_ACCESSED)

#define YOUNG (_PAGE_ACCESSED)



/* Sized as 8 rather than 4 to allow checking the PTE's PRU bit against whether

   the fault happened in user mode or privileged mode. */

static struct expevt_lookup expevt_lookup_table = {
@@ -164,12 +116,10 @@ static struct expevt_lookup expevt_lookup_table = { 
   general fault handling in fault.c which deals with mapping file-backed

   pages, stack growth, segmentation faults, swapping etc etc)

 */

asmlinkage int do_fast_page_fault(unsigned long long ssr_md,

				  unsigned long long expevt,

asmlinkage int __kprobes

do_fast_page_fault(unsigned long long ssr_md, unsigned long long expevt,

		   unsigned long address)

{

	struct task_struct *tsk;

	struct mm_struct *mm;

	unsigned long long protection_flags;

	unsigned long long index;

	unsigned long long expevt4;
@@ -194,32 +144,5 @@ asmlinkage int do_fast_page_fault(unsigned long long ssr_md, 
	if (expevt_lookup_table.is_text_access[index])

		set_thread_fault_code(FAULT_CODE_ITLB);



	/* SIM

	 * Note this is now called with interrupts still disabled

	 * This is to cope with being called for a missing IO port

	 * address with interrupts disabled. This should be fixed as

	 * soon as we have a better 'fast path' miss handler.

	 *

	 * Plus take care how you try and debug this stuff.

	 * For example, writing debug data to a port which you

	 * have just faulted on is not going to work.

	 */



	tsk = current;

	mm = tsk->mm;



	if (is_vmalloc_addr((void *)address)) {

		if (ssr_md)

			/*

			 * Process-contexts can never have this address

			 * range mapped

			 */

			if (handle_vmalloc_fault(mm, protection_flags, address) == 0)

				return 0;

	} else if (!in_interrupt() && mm) {

		if (handle_tlbmiss(mm, protection_flags, address) == 0)

			return 0;

	}



	return 1;

	return handle_tlbmiss(protection_flags, address);

}