x86, mtrr: Use explicit sizing and padding for the 64-bit ioctls

Specify the data structures for the 64-bit ioctls with explicit sizing
and padding so that the x32 kernel will correctly use the 64-bit forms
of these ioctls.  Note that these ioctls are bogus in both forms on
both 32 and 64 bits; even on 64 bits the maximum MTRR size is only 44
bits long.

Note that nothing really is supposed to use these ioctls and that the
preferred interface is text strings on /proc/mtrr, or better yet,
nothing at all (use /sys/bus/pci/devices/*/resource*_wc for write
combining; that uses PAT not MTRRs.)

Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Cc: H. J. Lu <hjl.tools@gmail.com>
Tested-by: Nitin A. Kamble <nitin.a.kamble@intel.com>
Link: http://lkml.kernel.org/n/tip-vwvnlu3hjmtkwvij4qxtm90l@git.kernel.org
Signed-off-by: H. Peter Anvin <hpa@zytor.com>

1 files changed, 6 insertions, 4 deletions

diff --git a/arch/x86/kernel/cpu/mtrr/if.c b/arch/x86/kernel/cpu/mtrr/if.c
index 79289632cb27..a041e094b8b9 100644
--- a/arch/x86/kernel/cpu/mtrr/if.c
+++ b/arch/x86/kernel/cpu/mtrr/if.c
@@ -167,6 +167,7 @@ mtrr_ioctl(struct file *file, unsigned int cmd, unsigned long __arg)
 {
         int err = 0;
         mtrr_type type;
+        unsigned long base;
         unsigned long size;
         struct mtrr_sentry sentry;
         struct mtrr_gentry gentry;
@@ -267,14 +268,14 @@ mtrr_ioctl(struct file *file, unsigned int cmd, unsigned long __arg)
 #endif
                 if (gentry.regnum >= num_var_ranges)
                         return -EINVAL;
-                mtrr_if->get(gentry.regnum, &gentry.base, &size, &type);
+                mtrr_if->get(gentry.regnum, &base, &size, &type);
 
                 /* Hide entries that go above 4GB */
-                if (gentry.base + size - 1 >= (1UL << (8 * sizeof(gentry.size) - PAGE_SHIFT))
+                if (base + size - 1 >= (1UL << (8 * sizeof(gentry.size) - PAGE_SHIFT))
                     || size >= (1UL << (8 * sizeof(gentry.size) - PAGE_SHIFT)))
                         gentry.base = gentry.size = gentry.type = 0;
                 else {
-                        gentry.base <<= PAGE_SHIFT;
+                        gentry.base = base << PAGE_SHIFT;
                         gentry.size = size << PAGE_SHIFT;
                         gentry.type = type;
                 }
@@ -321,11 +322,12 @@ mtrr_ioctl(struct file *file, unsigned int cmd, unsigned long __arg)
 #endif
                 if (gentry.regnum >= num_var_ranges)
                         return -EINVAL;
-                mtrr_if->get(gentry.regnum, &gentry.base, &size, &type);
+                mtrr_if->get(gentry.regnum, &base, &size, &type);
                 /* Hide entries that would overflow */
                 if (size != (__typeof__(gentry.size))size)
                         gentry.base = gentry.size = gentry.type = 0;
                 else {
+                        gentry.base = base;
                         gentry.size = size;
                         gentry.type = type;
                 }