Commit 80eff6c4 authored by Balbir Singh's avatar Balbir Singh Committed by Michael Ellerman
Browse files

powerpc/xmon: Support dumping software pagetables 



It would be nice to be able to dump page tables in a particular
context.

eg: dumping vmalloc space:

  0:mon> dv 0xd00037fffff00000
  pgd  @ 0xc0000000017c0000
  pgdp @ 0xc0000000017c00d8 = 0x00000000f10b1000
  pudp @ 0xc0000000f10b13f8 = 0x00000000f10d0000
  pmdp @ 0xc0000000f10d1ff8 = 0x00000000f1102000
  ptep @ 0xc0000000f1102780 = 0xc0000000f1ba018e
  Maps physical address = 0x00000000f1ba0000
  Flags = Accessed Dirty Read Write

This patch does not replicate the complex code of dump_pagetable and
has no support for bolted linear mapping, thats why I've it's called
dump virtual page table support. The format of the PTE can be expanded
even further to add more useful information about the flags in the PTE
if required.

Signed-off-by: default avatarBalbir Singh <bsingharora@gmail.com>
[mpe: Bike shed the output format, show the pgdir, fix build failures]
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
parent bf751e30

arch/powerpc/xmon/xmon.c

+116 −0
Original line number Diff line number Diff line
@@ -28,6 +28,7 @@ 
#include <linux/bug.h>

#include <linux/nmi.h>

#include <linux/ctype.h>

#include <linux/highmem.h>



#include <asm/debugfs.h>

#include <asm/ptrace.h>
@@ -127,6 +128,7 @@ static void byterev(unsigned char *, int); 
static void memex(void);

static int bsesc(void);

static void dump(void);

static void show_pte(unsigned long);

static void prdump(unsigned long, long);

static int ppc_inst_dump(unsigned long, long, int);

static void dump_log_buf(void);
@@ -234,6 +236,7 @@ Commands:\n\ 
#endif

  "\

  dr	dump stream of raw bytes\n\

  dv	dump virtual address translation \n\

  dt	dump the tracing buffers (uses printk)\n\

  dtc	dump the tracing buffers for current CPU (uses printk)\n\

"
@@ -2613,6 +2616,9 @@ dump(void) 
		dump_log_buf();

	} else if (c == 'o') {

		dump_opal_msglog();

	} else if (c == 'v') {

		/* dump virtual to physical translation */

		show_pte(adrs);

	} else if (c == 'r') {

		scanhex(&ndump);

		if (ndump == 0)
@@ -2946,6 +2952,116 @@ static void show_task(struct task_struct *tsk) 
		tsk->comm);

}



#ifdef CONFIG_PPC_BOOK3S_64

void format_pte(void *ptep, unsigned long pte)

{

	printf("ptep @ 0x%016lx = 0x%016lx\n", (unsigned long)ptep, pte);

	printf("Maps physical address = 0x%016lx\n", pte & PTE_RPN_MASK);



	printf("Flags = %s%s%s%s%s\n",

	       (pte & _PAGE_ACCESSED) ? "Accessed " : "",

	       (pte & _PAGE_DIRTY)    ? "Dirty " : "",

	       (pte & _PAGE_READ)     ? "Read " : "",

	       (pte & _PAGE_WRITE)    ? "Write " : "",

	       (pte & _PAGE_EXEC)     ? "Exec " : "");

}



static void show_pte(unsigned long addr)

{

	unsigned long tskv = 0;

	struct task_struct *tsk = NULL;

	struct mm_struct *mm;

	pgd_t *pgdp, *pgdir;

	pud_t *pudp;

	pmd_t *pmdp;

	pte_t *ptep;



	if (!scanhex(&tskv))

		mm = &init_mm;

	else

		tsk = (struct task_struct *)tskv;



	if (tsk == NULL)

		mm = &init_mm;

	else

		mm = tsk->active_mm;



	if (setjmp(bus_error_jmp) != 0) {

		catch_memory_errors = 0;

		printf("*** Error dumping pte for task %p\n", tsk);

		return;

	}



	catch_memory_errors = 1;

	sync();



	if (mm == &init_mm) {

		pgdp = pgd_offset_k(addr);

		pgdir = pgd_offset_k(0);

	} else {

		pgdp = pgd_offset(mm, addr);

		pgdir = pgd_offset(mm, 0);

	}



	if (pgd_none(*pgdp)) {

		printf("no linux page table for address\n");

		return;

	}



	printf("pgd  @ 0x%016lx\n", pgdir);



	if (pgd_huge(*pgdp)) {

		format_pte(pgdp, pgd_val(*pgdp));

		return;

	}

	printf("pgdp @ 0x%016lx = 0x%016lx\n", pgdp, pgd_val(*pgdp));



	pudp = pud_offset(pgdp, addr);



	if (pud_none(*pudp)) {

		printf("No valid PUD\n");

		return;

	}



	if (pud_huge(*pudp)) {

		format_pte(pudp, pud_val(*pudp));

		return;

	}



	printf("pudp @ 0x%016lx = 0x%016lx\n", pudp, pud_val(*pudp));



	pmdp = pmd_offset(pudp, addr);



	if (pmd_none(*pmdp)) {

		printf("No valid PMD\n");

		return;

	}



	if (pmd_huge(*pmdp)) {

		format_pte(pmdp, pmd_val(*pmdp));

		return;

	}

	printf("pmdp @ 0x%016lx = 0x%016lx\n", pmdp, pmd_val(*pmdp));



	ptep = pte_offset_map(pmdp, addr);

	if (pte_none(*ptep)) {

		printf("no valid PTE\n");

		return;

	}



	format_pte(ptep, pte_val(*ptep));



	sync();

	__delay(200);

	catch_memory_errors = 0;

}

#else

static void show_pte(unsigned long addr)

{

	printf("show_pte not yet implemented\n");

}

#endif /* CONFIG_PPC_BOOK3S_64 */



static void show_tasks(void)

{

	unsigned long tskv;

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