[Crash-utility] [PATCH] arm64: incorrect translation, physical address include flags

[Dave Anderson]

----- Original Message -----
> Hi
> 
> We have seen a problem when translating virtual to physical
> addresses. It appears that upper flags are not cleared.
> 
> Example below, observe that physical address is incorrect for 'PAGE:',
> it include flags in upper bits. This value is also returned from
> arm64_vtop_3level_4k().
> 
> crash> vtop ffffffc081000000
> VIRTUAL           PHYSICAL
> ffffffc081000000  81000000
> 
> PAGE DIRECTORY: ffffffc00007d000
>    PGD: ffffffc00007d810 => 61fe003
>    PMD: ffffffc0061fe040 => 20000081000711
>   PAGE: 20000081000000  (2MB)
> 
>      PTE        PHYSICAL  FLAGS
> 20000081000711  81000000  (VALID|SHARED|AF|PXN)
> 
> vtop: WARNING: sparsemem: invalid section number: 8388610
> ---
>  arm64.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/arm64.c b/arm64.c
> index d1d75c4..2320df9 100644
> --- a/arm64.c
> +++ b/arm64.c
> @@ -802,6 +802,7 @@ arm64_vtop_3level_4k(ulong pgd, ulong vaddr, physaddr_t
> *paddr, int verbose)
>  
>  	if ((pmd_val & PMD_TYPE_MASK) == PMD_TYPE_SECT) {
>  		ulong sectionbase = pmd_val & SECTION_PAGE_MASK_2MB;
> +		sectionbase &= PHYS_MASK;
>  		if (verbose) {
>  			fprintf(fp, "  PAGE: %lx  (2MB)\n\n", sectionbase);
>  			arm64_translate_pte(pmd_val, 0, 0);
> --
> 1.9.1
> 
> --
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> Crash-utility at redhat.com
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Hi Johan,

I also see it with 64k pages when the referenced memory is in the high ranges.
But there are actually two issues here, because the SECTION_PAGE_MASK_2MB and 
SECTION_PAGE_MASK_512MB macros are incorrectly being defined as 32-bit values.

How does this patch work for you?:


--- a/arm64.c
+++ b/arm64.c
@@ -702,8 +702,8 @@ arm64_uvtop(struct task_context *tc, ulong uvaddr, physaddr_t *paddr, int verbos
 #define PMD_TYPE_MASK   3
 #define PMD_TYPE_SECT   1
 #define PMD_TYPE_TABLE  2
-#define SECTION_PAGE_MASK_2MB    (~((MEGABYTES(2))-1))
-#define SECTION_PAGE_MASK_512MB  (~((MEGABYTES(512))-1))
+#define SECTION_PAGE_MASK_2MB    ((long)(~((MEGABYTES(2))-1)))
+#define SECTION_PAGE_MASK_512MB  ((long)(~((MEGABYTES(512))-1)))
 
 static int 
 arm64_vtop_2level_64k(ulong pgd, ulong vaddr, physaddr_t *paddr, int verbose)
@@ -729,7 +729,7 @@ arm64_vtop_2level_64k(ulong pgd, ulong vaddr, physaddr_t *paddr, int verbose)
         */
 
        if ((pgd_val & PMD_TYPE_MASK) == PMD_TYPE_SECT) {
-               ulong sectionbase = pgd_val & SECTION_PAGE_MASK_512MB;
+               ulong sectionbase = (pgd_val & SECTION_PAGE_MASK_512MB) & PHYS_MASK;
                if (verbose) {
                        fprintf(fp, "  PAGE: %lx  (512MB)\n\n", sectionbase);
                        arm64_translate_pte(pgd_val, 0, 0);
@@ -801,7 +801,7 @@ arm64_vtop_3level_4k(ulong pgd, ulong vaddr, physaddr_t *paddr, int verbose)
                goto no_page;
 
        if ((pmd_val & PMD_TYPE_MASK) == PMD_TYPE_SECT) {
-               ulong sectionbase = pmd_val & SECTION_PAGE_MASK_2MB;
+               ulong sectionbase = (pmd_val & SECTION_PAGE_MASK_2MB) & PHYS_MASK;
                if (verbose) {
                        fprintf(fp, "  PAGE: %lx  (2MB)\n\n", sectionbase);
                        arm64_translate_pte(pmd_val, 0, 0);