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x86/mpx: Support 32-bit binaries on 64-bit kernels

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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>
This commit is contained in:
Dave Hansen
2015-06-07 11:37:05 -07:00
committed by Ingo Molnar
parent 6ac52bb491
commit 613fcb7d3c
2 changed files with 179 additions and 53 deletions
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62
arch/x86/include/asm/mpx.h
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@@ -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).
/*
* 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_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).
#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)
/*
* The 32-bit directory is 4MB (2^22) in size, and with 4-byte
* entries it has 2^20 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_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)
#else
/*
* 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_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
#endif
#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);