libpagemap: Mask off page shift to get page frame number

see comment above pagemap_read() from the kernel

Bug: 17332389
Change-Id: Iaec9a2c8d2783f5c1e7ba06d9c7156305abe0453
Signed-off-by: Daniel Rosenberg <drosen@google.com>

1 files changed, 12 insertions, 0 deletions

diff --git a/libpagemap/pm_process.c b/libpagemap/pm_process.c
index 50791ef9..0994cede 100644
--- a/libpagemap/pm_process.c
+++ b/libpagemap/pm_process.c
@@ -30,6 +30,8 @@ static int read_maps(pm_process_t *proc);
 
 #define MAX_FILENAME 64
 
+#define PFN_MASK 0x7fffffffffffff
+
 int pm_process_create(pm_kernel_t *ker, pid_t pid, pm_process_t **proc_out) {
     pm_process_t *proc;
     char filename[MAX_FILENAME];
@@ -100,6 +102,11 @@ int pm_process_usage(pm_process_t *proc, pm_memusage_t *usage_out) {
     return pm_process_usage_flags(proc, usage_out, 0, 0);
 }
 
+static inline uint64_t get_pfn(uint64_t p)
+{
+    return p & PFN_MASK;
+}
+
 int pm_process_pagemap_range(pm_process_t *proc,
                              uint64_t low, uint64_t high,
                              uint64_t **range_out, size_t *len) {
@@ -107,6 +114,7 @@ int pm_process_pagemap_range(pm_process_t *proc,
     uint64_t numpages;
     uint64_t *range;
     off64_t off;
+    uint64_t i;
     int error;
 
     if (!proc || (low > high) || !range_out || !len)
@@ -144,6 +152,10 @@ int pm_process_pagemap_range(pm_process_t *proc,
         return error;
     }
 
+    for(i = 0; i < numpages; i++) {
+        range[i] = get_pfn(range[i]);
+    }
+
     *range_out = range;
     *len = numpages;