From: Ricardo Neri <ricardo.neri-calderon@linux.intel.com>
To: Ingo Molnar <mingo@redhat.com>,
Thomas Gleixner <tglx@linutronix.de>,
"H. Peter Anvin" <hpa@zytor.com>,
Andy Lutomirski <luto@kernel.org>, Borislav Petkov <bp@suse.de>
Cc: Peter Zijlstra <peterz@infradead.org>,
Andrew Morton <akpm@linux-foundation.org>,
Brian Gerst <brgerst@gmail.com>,
Chris Metcalf <cmetcalf@mellanox.com>,
Dave Hansen <dave.hansen@linux.intel.com>,
Paolo Bonzini <pbonzini@redhat.com>,
Liang Z Li <liang.z.li@intel.com>,
Masami Hiramatsu <mhiramat@kernel.org>,
Huang Rui <ray.huang@amd.com>, Jiri Slaby <jslaby@suse.cz>,
Jonathan Corbet <corbet@lwn.net>,
"Michael S. Tsirkin" <mst@redhat.com>,
Paul Gortmaker <paul.gortmaker@windriver.com>,
Vlastimil Babka <vbabka@suse.cz>, Chen Yucong <slaoub@gmail.com>,
Alexandre Julliard <julliard@winehq.org>,
Stas Sergeev <stsp@list.ru>, Fenghua Yu <fenghua.yu@intel.com>,
"Ravi V. Shankar" <ravi.v.shankar@intel.com>,
Shuah Khan <shuah@kernel.org>,
linux-kernel@vger.kernel.org, x86@kernel.org,
linux-msdos@vger.kernel.org, wine-devel@winehq.org,
Ricardo Neri <ricardo.neri-calderon@linux.intel.com>,
Adam Buchbinder <adam.buchbinder@gmail.com>,
Colin Ian King <colin.king@canonical.com>,
Lorenzo Stoakes <lstoakes@gmail.com>,
Qiaowei Ren <qiaowei.ren@intel.com>,
Arnaldo Carvalho de Melo <acme@redhat.com>,
Adrian Hunter <adrian.hunter@intel.com>,
Kees Cook <keescook@chromium.org>,
Thomas Garnier <thgarnie@google.com>,
Dmitry Vyukov <dvyukov@google.com>
Subject: [PATCH v7 13/26] x86/insn-eval: Add function to get default params of code segment
Date: Fri, 5 May 2017 11:17:11 -0700 [thread overview]
Message-ID: <20170505181724.55000-14-ricardo.neri-calderon@linux.intel.com> (raw)
In-Reply-To: <20170505181724.55000-1-ricardo.neri-calderon@linux.intel.com>
This function returns the default values of the address and operand sizes
as specified in the segment descriptor. This information is determined
from the D and L bits. Hence, it can be used for both IA-32e 64-bit and
32-bit legacy modes. For virtual-8086 mode, the default address and
operand sizes are always 2 bytes.
The D bit is only meaningful for code segments. Thus, these functions
always use the code segment selector contained in regs.
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Adam Buchbinder <adam.buchbinder@gmail.com>
Cc: Colin Ian King <colin.king@canonical.com>
Cc: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Qiaowei Ren <qiaowei.ren@intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Thomas Garnier <thgarnie@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Borislav Petkov <bp@suse.de>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Ravi V. Shankar <ravi.v.shankar@intel.com>
Cc: x86@kernel.org
Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com>
---
arch/x86/include/asm/insn-eval.h | 6 ++++
arch/x86/lib/insn-eval.c | 65 ++++++++++++++++++++++++++++++++++++++++
2 files changed, 71 insertions(+)
diff --git a/arch/x86/include/asm/insn-eval.h b/arch/x86/include/asm/insn-eval.h
index 7f3c7fe..9ed1c88 100644
--- a/arch/x86/include/asm/insn-eval.h
+++ b/arch/x86/include/asm/insn-eval.h
@@ -11,9 +11,15 @@
#include <linux/err.h>
#include <asm/ptrace.h>
+struct insn_code_seg_defaults {
+ unsigned char address_bytes;
+ unsigned char operand_bytes;
+};
+
void __user *insn_get_addr_ref(struct insn *insn, struct pt_regs *regs);
int insn_get_modrm_rm_off(struct insn *insn, struct pt_regs *regs);
unsigned long insn_get_seg_base(struct pt_regs *regs, struct insn *insn,
int regoff);
+struct insn_code_seg_defaults insn_get_code_seg_defaults(struct pt_regs *regs);
#endif /* _ASM_X86_INSN_EVAL_H */
diff --git a/arch/x86/lib/insn-eval.c b/arch/x86/lib/insn-eval.c
index c77ed80..693e5a8 100644
--- a/arch/x86/lib/insn-eval.c
+++ b/arch/x86/lib/insn-eval.c
@@ -603,6 +603,71 @@ static unsigned long get_seg_limit(struct pt_regs *regs, struct insn *insn,
}
/**
+ * insn_get_code_seg_defaults() - Obtain code segment default parameters
+ * @regs: Structure with register values as seen when entering kernel mode
+ *
+ * Obtain the default parameters of the code segment: address and operand sizes.
+ * The code segment is obtained from the selector contained in the CS register
+ * in regs. In protected mode, the default address is determined by inspecting
+ * the L and D bits of the segment descriptor. In virtual-8086 mode, the default
+ * is always two bytes for both address and operand sizes.
+ *
+ * Return: A populated insn_code_seg_defaults structure on success. The
+ * structure contains only zeros on failure.
+ */
+struct insn_code_seg_defaults insn_get_code_seg_defaults(struct pt_regs *regs)
+{
+ struct desc_struct *desc;
+ struct insn_code_seg_defaults defs;
+ unsigned short sel;
+ /*
+ * The most significant byte of AR_TYPE_MASK determines whether a
+ * segment contains data or code.
+ */
+ unsigned int type_mask = AR_TYPE_MASK & (1 << 11);
+
+ memset(&defs, 0, sizeof(defs));
+
+ if (v8086_mode(regs)) {
+ defs.address_bytes = 2;
+ defs.operand_bytes = 2;
+ return defs;
+ }
+
+ sel = (unsigned short)regs->cs;
+
+ desc = get_desc(sel);
+ if (!desc)
+ return defs;
+
+ /* if data segment, return */
+ if (!(desc->b & type_mask))
+ return defs;
+
+ switch ((desc->l << 1) | desc->d) {
+ case 0: /* Legacy mode. CS.L=0, CS.D=0 */
+ defs.address_bytes = 2;
+ defs.operand_bytes = 2;
+ break;
+ case 1: /* Legacy mode. CS.L=0, CS.D=1 */
+ defs.address_bytes = 4;
+ defs.operand_bytes = 4;
+ break;
+ case 2: /* IA-32e 64-bit mode. CS.L=1, CS.D=0 */
+ defs.address_bytes = 8;
+ defs.operand_bytes = 4;
+ break;
+ case 3: /* Invalid setting. CS.L=1, CS.D=1 */
+ /* fall through */
+ default:
+ defs.address_bytes = 0;
+ defs.operand_bytes = 0;
+ }
+
+ return defs;
+}
+
+/**
* insn_get_reg_offset_modrm_rm() - Obtain register in r/m part of ModRM byte
* @insn: Instruction structure containing the ModRM byte
* @regs: Structure with register values as seen when entering kernel mode
--
2.9.3
next prev parent reply other threads:[~2017-05-05 18:19 UTC|newest]
Thread overview: 81+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-05-05 18:16 [PATCH v7 00/26] x86: Enable User-Mode Instruction Prevention Ricardo Neri
2017-05-05 18:16 ` [PATCH v7 01/26] ptrace,x86: Make user_64bit_mode() available to 32-bit builds Ricardo Neri
2017-05-21 14:19 ` Borislav Petkov
2017-05-05 18:17 ` [PATCH v7 02/26] x86/mm: Relocate page fault error codes to traps.h Ricardo Neri
2017-05-21 14:23 ` Borislav Petkov
2017-05-27 3:40 ` Ricardo Neri
2017-05-27 10:13 ` Borislav Petkov
2017-06-01 3:09 ` Ricardo Neri
2017-05-05 18:17 ` [PATCH v7 03/26] x86/mpx: Use signed variables to compute effective addresses Ricardo Neri
2017-05-05 18:17 ` [PATCH v7 04/26] x86/mpx: Do not use SIB.index if its value is 100b and ModRM.mod is not 11b Ricardo Neri
2017-05-24 13:37 ` Borislav Petkov
2017-05-27 3:36 ` Ricardo Neri
2017-05-05 18:17 ` [PATCH v7 05/26] x86/mpx: Do not use SIB.base if its value is 101b and ModRM.mod = 0 Ricardo Neri
2017-05-29 13:07 ` Borislav Petkov
2017-06-06 6:08 ` Ricardo Neri
2017-05-05 18:17 ` [PATCH v7 06/26] x86/mpx, x86/insn: Relocate insn util functions to a new insn-eval file Ricardo Neri
2017-05-05 18:17 ` [PATCH v7 07/26] x86/insn-eval: Do not BUG on invalid register type Ricardo Neri
2017-05-29 16:37 ` Borislav Petkov
2017-06-06 6:06 ` Ricardo Neri
2017-06-06 11:58 ` Borislav Petkov
2017-06-07 0:28 ` Ricardo Neri
2017-06-07 12:21 ` Borislav Petkov
2017-05-05 18:17 ` [PATCH v7 08/26] x86/insn-eval: Add a utility function to get register offsets Ricardo Neri
2017-05-29 17:16 ` Borislav Petkov
2017-06-06 6:02 ` Ricardo Neri
2017-05-05 18:17 ` [PATCH v7 09/26] x86/insn-eval: Add utility function to identify string instructions Ricardo Neri
2017-05-29 21:48 ` Borislav Petkov
2017-06-06 6:01 ` Ricardo Neri
2017-06-06 12:04 ` Borislav Petkov
2017-05-05 18:17 ` [PATCH v7 10/26] x86/insn-eval: Add utility functions to get segment selector Ricardo Neri
2017-05-30 10:35 ` Borislav Petkov
2017-06-15 18:37 ` Ricardo Neri
2017-06-15 19:04 ` Ricardo Neri
2017-06-19 15:29 ` Borislav Petkov
2017-06-19 15:37 ` Borislav Petkov
2017-05-05 18:17 ` [PATCH v7 11/26] x86/insn-eval: Add utility function to get segment descriptor Ricardo Neri
2017-05-05 18:17 ` [PATCH v7 12/26] x86/insn-eval: Add utility functions to get segment descriptor base address and limit Ricardo Neri
2017-05-31 16:58 ` Borislav Petkov
2017-06-03 17:23 ` Ricardo Neri
2017-05-05 18:17 ` Ricardo Neri [this message]
2017-06-07 12:59 ` [PATCH v7 13/26] x86/insn-eval: Add function to get default params of code segment Borislav Petkov
2017-06-15 19:24 ` Ricardo Neri
2017-06-19 17:11 ` Borislav Petkov
2017-05-05 18:17 ` [PATCH v7 14/26] x86/insn-eval: Indicate a 32-bit displacement if ModRM.mod is 0 and ModRM.rm is 5 Ricardo Neri
2017-06-07 13:15 ` Borislav Petkov
2017-06-15 19:36 ` Ricardo Neri
2017-05-05 18:17 ` [PATCH v7 15/26] x86/insn-eval: Incorporate segment base and limit in linear address computation Ricardo Neri
2017-05-05 18:17 ` [PATCH v7 16/26] x86/insn-eval: Support both signed 32-bit and 64-bit effective addresses Ricardo Neri
2017-06-07 15:48 ` Borislav Petkov
2017-07-25 23:48 ` Ricardo Neri
2017-07-27 13:26 ` Borislav Petkov
2017-07-28 2:04 ` Ricardo Neri
2017-07-28 6:50 ` Borislav Petkov
2017-06-07 15:49 ` Borislav Petkov
2017-06-15 19:58 ` Ricardo Neri
2017-05-05 18:17 ` [PATCH v7 17/26] x86/insn-eval: Handle 32-bit address encodings in virtual-8086 mode Ricardo Neri
2017-05-05 18:17 ` [PATCH v7 18/26] x86/insn-eval: Add support to resolve 16-bit addressing encodings Ricardo Neri
2017-06-07 16:28 ` Borislav Petkov
2017-06-15 21:50 ` Ricardo Neri
2017-05-05 18:17 ` [PATCH v7 19/26] x86/insn-eval: Add wrapper function for 16-bit and 32-bit address encodings Ricardo Neri
2017-05-05 18:17 ` [PATCH v7 20/26] x86/cpufeature: Add User-Mode Instruction Prevention definitions Ricardo Neri
2017-05-06 9:04 ` Paolo Bonzini
2017-05-11 3:23 ` Ricardo Neri
2017-06-07 18:24 ` Borislav Petkov
2017-05-05 18:17 ` [PATCH v7 21/26] x86: Add emulation code for UMIP instructions Ricardo Neri
2017-06-08 18:38 ` Borislav Petkov
2017-06-17 1:34 ` Ricardo Neri
2017-05-05 18:17 ` [PATCH v7 22/26] x86/umip: Force a page fault when unable to copy emulated result to user Ricardo Neri
2017-06-09 11:02 ` Borislav Petkov
2017-07-25 23:50 ` Ricardo Neri
2017-05-05 18:17 ` [PATCH v7 23/26] x86/traps: Fixup general protection faults caused by UMIP Ricardo Neri
2017-06-09 13:02 ` Borislav Petkov
2017-07-25 23:51 ` Ricardo Neri
2017-05-05 18:17 ` [PATCH v7 24/26] x86: Enable User-Mode Instruction Prevention Ricardo Neri
2017-06-09 16:10 ` Borislav Petkov
2017-07-26 0:44 ` Ricardo Neri
2017-07-27 13:57 ` Borislav Petkov
2017-05-05 18:17 ` [PATCH v7 25/26] selftests/x86: Add tests for " Ricardo Neri
2017-05-05 18:17 ` [PATCH v7 26/26] selftests/x86: Add tests for instruction str and sldt Ricardo Neri
2017-05-17 18:42 ` [PATCH v7 00/26] x86: Enable User-Mode Instruction Prevention Ricardo Neri
2017-05-27 3:49 ` Neri, Ricardo
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