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authorDave Hansen <dave.hansen@linux.intel.com>2015-06-07 11:37:05 -0700
committerIngo Molnar <mingo@kernel.org>2015-06-09 12:24:34 +0200
commit613fcb7d3c79ec25b5913a6aa974c9047c31e68c (patch)
treecf4b979e9bf8a951a63eb71ddcd536508148e05e /arch/x86/include
parent6ac52bb4913eadfa327138b91aab5d37234a2c3b (diff)
x86/mpx: Support 32-bit binaries on 64-bit kernels
Right now, the kernel can only switch between 64-bit and 32-bit binaries at compile time. This patch adds support for 32-bit binaries on 64-bit kernels when we support ia32 emulation. We essentially choose which set of table sizes to use when doing arithmetic for the bounds table calculations. This also uses a different approach for calculating the table indexes than before. I think the new one makes it much more clear what is going on, and allows us to share more code between the 32-bit and 64-bit cases. Based-on-patch-by: Qiaowei Ren <qiaowei.ren@intel.com> Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Dave Hansen <dave@sr71.net> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/20150607183705.E01F21E2@viggo.jf.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86/include')
-rw-r--r--arch/x86/include/asm/mpx.h62
1 files changed, 30 insertions, 32 deletions
diff --git a/arch/x86/include/asm/mpx.h b/arch/x86/include/asm/mpx.h
index 99d374eb7b08..7a35495275a9 100644
--- a/arch/x86/include/asm/mpx.h
+++ b/arch/x86/include/asm/mpx.h
@@ -13,49 +13,47 @@
#define MPX_BNDCFG_ENABLE_FLAG 0x1
#define MPX_BD_ENTRY_VALID_FLAG 0x1
-#ifdef CONFIG_X86_64
-
-/* upper 28 bits [47:20] of the virtual address in 64-bit used to
- * index into bounds directory (BD).
- */
-#define MPX_BD_ENTRY_OFFSET 28
-#define MPX_BD_ENTRY_SHIFT 3
-/* bits [19:3] of the virtual address in 64-bit used to index into
- * bounds table (BT).
+/*
+ * The upper 28 bits [47:20] of the virtual address in 64-bit
+ * are used to index into bounds directory (BD).
+ *
+ * The directory is 2G (2^31) in size, and with 8-byte entries
+ * it has 2^28 entries.
*/
-#define MPX_BT_ENTRY_OFFSET 17
-#define MPX_BT_ENTRY_SHIFT 5
-#define MPX_IGN_BITS 3
-#define MPX_BD_ENTRY_TAIL 3
+#define MPX_BD_SIZE_BYTES_64 (1UL<<31)
+#define MPX_BD_ENTRY_BYTES_64 8
+#define MPX_BD_NR_ENTRIES_64 (MPX_BD_SIZE_BYTES_64/MPX_BD_ENTRY_BYTES_64)
-#else
-
-#define MPX_BD_ENTRY_OFFSET 20
-#define MPX_BD_ENTRY_SHIFT 2
-#define MPX_BT_ENTRY_OFFSET 10
-#define MPX_BT_ENTRY_SHIFT 4
-#define MPX_IGN_BITS 2
-#define MPX_BD_ENTRY_TAIL 2
+/*
+ * The 32-bit directory is 4MB (2^22) in size, and with 4-byte
+ * entries it has 2^20 entries.
+ */
+#define MPX_BD_SIZE_BYTES_32 (1UL<<22)
+#define MPX_BD_ENTRY_BYTES_32 4
+#define MPX_BD_NR_ENTRIES_32 (MPX_BD_SIZE_BYTES_32/MPX_BD_ENTRY_BYTES_32)
-#endif
+/*
+ * A 64-bit table is 4MB total in size, and an entry is
+ * 4 64-bit pointers in size.
+ */
+#define MPX_BT_SIZE_BYTES_64 (1UL<<22)
+#define MPX_BT_ENTRY_BYTES_64 32
+#define MPX_BT_NR_ENTRIES_64 (MPX_BT_SIZE_BYTES_64/MPX_BT_ENTRY_BYTES_64)
-#define MPX_BD_SIZE_BYTES (1UL<<(MPX_BD_ENTRY_OFFSET+MPX_BD_ENTRY_SHIFT))
-#define MPX_BT_SIZE_BYTES (1UL<<(MPX_BT_ENTRY_OFFSET+MPX_BT_ENTRY_SHIFT))
+/*
+ * A 32-bit table is 16kB total in size, and an entry is
+ * 4 32-bit pointers in size.
+ */
+#define MPX_BT_SIZE_BYTES_32 (1UL<<14)
+#define MPX_BT_ENTRY_BYTES_32 16
+#define MPX_BT_NR_ENTRIES_32 (MPX_BT_SIZE_BYTES_32/MPX_BT_ENTRY_BYTES_32)
#define MPX_BNDSTA_TAIL 2
#define MPX_BNDCFG_TAIL 12
#define MPX_BNDSTA_ADDR_MASK (~((1UL<<MPX_BNDSTA_TAIL)-1))
-
#define MPX_BNDCFG_ADDR_MASK (~((1UL<<MPX_BNDCFG_TAIL)-1))
#define MPX_BNDSTA_ERROR_CODE 0x3
-#define MPX_BD_ENTRY_MASK ((1<<MPX_BD_ENTRY_OFFSET)-1)
-#define MPX_BT_ENTRY_MASK ((1<<MPX_BT_ENTRY_OFFSET)-1)
-#define MPX_GET_BD_ENTRY_OFFSET(addr) ((((addr)>>(MPX_BT_ENTRY_OFFSET+ \
- MPX_IGN_BITS)) & MPX_BD_ENTRY_MASK) << MPX_BD_ENTRY_SHIFT)
-#define MPX_GET_BT_ENTRY_OFFSET(addr) ((((addr)>>MPX_IGN_BITS) & \
- MPX_BT_ENTRY_MASK) << MPX_BT_ENTRY_SHIFT)
-
#ifdef CONFIG_X86_INTEL_MPX
siginfo_t *mpx_generate_siginfo(struct pt_regs *regs);
int mpx_handle_bd_fault(void);