Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1715524

[PATCH v8 10/28] x86/insn-eval: Add a utility function to get register offsets

Show all headers | View raw

The function get_reg_offset() returns the offset to the register the
argument specifies as indicated in an enumeration of type offset. Callers
of this function would need the definition of such enumeration. This is
not needed. Instead, add helper functions for this purpose. These functions
are useful in cases when, for instance, the caller needs to decide whether
the operand is a register or a memory location by looking at the rm part
of the ModRM byte. As of now, this is the only helper function that is
needed.

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 |  1 +
 arch/x86/lib/insn-eval.c         | 15 +++++++++++++++
 2 files changed, 16 insertions(+)

diff --git a/arch/x86/include/asm/insn-eval.h b/arch/x86/include/asm/insn-eval.h
index 5cab1b1da84d..7e8c9633a377 100644
--- a/arch/x86/include/asm/insn-eval.h
+++ b/arch/x86/include/asm/insn-eval.h
@@ -12,5 +12,6 @@
 #include <asm/ptrace.h>
 
 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);
 
 #endif /* _ASM_X86_INSN_EVAL_H */
diff --git a/arch/x86/lib/insn-eval.c b/arch/x86/lib/insn-eval.c
index 3919458fecbf..c6120e9298f5 100644
--- a/arch/x86/lib/insn-eval.c
+++ b/arch/x86/lib/insn-eval.c
@@ -97,6 +97,21 @@ static int get_reg_offset(struct insn *insn, struct pt_regs *regs,
 	return regoff[regno];
 }
 
+/**
+ * insn_get_modrm_rm_off() - 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
+ *
+ * Return: The register indicated by the r/m part of the ModRM byte. The
+ * register is obtained as an offset from the base of pt_regs. In specific
+ * cases, the returned value can be -EDOM to indicate that the particular value
+ * of ModRM does not refer to a register and shall be ignored.
+ */
+int insn_get_modrm_rm_off(struct insn *insn, struct pt_regs *regs)
+{
+	return get_reg_offset(insn, regs, REG_TYPE_RM);
+}
+
 /*
  * return the address being referenced be instruction
  * for rm=3 returning the content of the rm reg
-- 
2.13.0

Back to linux.kernel | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

[PATCH v8 00/28] x86: Enable User-Mode Instruction Prevention Ricardo Neri <ricardo.neri-calderon@linux.intel.com> - 2017-08-19 02:30 +0200
  [PATCH v8 18/28] x86/insn-eval: Add support to resolve 32-bit address encodings Ricardo Neri <ricardo.neri-calderon@linux.intel.com> - 2017-08-19 02:30 +0200
  [PATCH v8 04/28] uprobes/x86: Use existing definitions for segment override prefixes Ricardo Neri <ricardo.neri-calderon@linux.intel.com> - 2017-08-19 02:30 +0200
  [PATCH v8 17/28] x86/insn-eval: Incorporate segment base in linear address computation Ricardo Neri <ricardo.neri-calderon@linux.intel.com> - 2017-08-19 02:30 +0200
  [PATCH v8 08/28] x86/mpx, x86/insn: Relocate insn util functions to a new insn-eval file Ricardo Neri <ricardo.neri-calderon@linux.intel.com> - 2017-08-19 02:30 +0200
  [PATCH v8 10/28] x86/insn-eval: Add a utility function to get register offsets Ricardo Neri <ricardo.neri-calderon@linux.intel.com> - 2017-08-19 02:30 +0200
  [PATCH v8 19/28] x86/insn-eval: Add wrapper function for 32 and 64-bit addresses Ricardo Neri <ricardo.neri-calderon@linux.intel.com> - 2017-08-19 02:40 +0200
  [PATCH v8 20/28] x86/insn-eval: Handle 32-bit address encodings in virtual-8086 mode Ricardo Neri <ricardo.neri-calderon@linux.intel.com> - 2017-08-19 02:40 +0200
  [PATCH v8 15/28] x86/insn-eval: Add function to get default params of code segment Ricardo Neri <ricardo.neri-calderon@linux.intel.com> - 2017-08-19 02:40 +0200
  [PATCH v8 05/28] x86/mpx: Use signed variables to compute effective addresses Ricardo Neri <ricardo.neri-calderon@linux.intel.com> - 2017-08-19 02:40 +0200
  [PATCH v8 16/28] x86/insn-eval: Indicate a 32-bit displacement if ModRM.mod is 0 and ModRM.rm is 101b Ricardo Neri <ricardo.neri-calderon@linux.intel.com> - 2017-08-19 02:40 +0200
  [PATCH v8 13/28] x86/insn-eval: Add utility function to get segment descriptor Ricardo Neri <ricardo.neri-calderon@linux.intel.com> - 2017-08-19 02:40 +0200
  [PATCH v8 03/28] ptrace,x86: Make user_64bit_mode() available to 32-bit builds Ricardo Neri <ricardo.neri-calderon@linux.intel.com> - 2017-08-19 02:40 +0200
  [PATCH v8 23/28] x86: Add emulation code for UMIP instructions Ricardo Neri <ricardo.neri-calderon@linux.intel.com> - 2017-08-19 02:40 +0200
  [PATCH v8 28/28] selftests/x86: Add tests for instruction str and sldt Ricardo Neri <ricardo.neri-calderon@linux.intel.com> - 2017-08-19 02:40 +0200
  [PATCH v8 21/28] x86/insn-eval: Add support to resolve 16-bit addressing encodings Ricardo Neri <ricardo.neri-calderon@linux.intel.com> - 2017-08-19 02:40 +0200
  [PATCH v8 12/28] x86/insn-eval: Add utility functions to get segment selector Ricardo Neri <ricardo.neri-calderon@linux.intel.com> - 2017-08-19 02:40 +0200
  [PATCH v8 01/28] x86/mm: Relocate page fault error codes to traps.h Ricardo Neri <ricardo.neri-calderon@linux.intel.com> - 2017-08-19 02:40 +0200
  [PATCH v8 27/28] selftests/x86: Add tests for User-Mode Instruction Prevention Ricardo Neri <ricardo.neri-calderon@linux.intel.com> - 2017-08-19 02:40 +0200
  [PATCH v8 24/28] x86/umip: Force a page fault when unable to copy emulated result to user Ricardo Neri <ricardo.neri-calderon@linux.intel.com> - 2017-08-19 02:40 +0200
  [PATCH v8 26/28] x86/traps: Fixup general protection faults caused by UMIP Ricardo Neri <ricardo.neri-calderon@linux.intel.com> - 2017-08-19 02:40 +0200
  [PATCH v8 07/28] x86/mpx: Do not use SIB.base if its value is 101b and ModRM.mod = 0 Ricardo Neri <ricardo.neri-calderon@linux.intel.com> - 2017-08-19 02:40 +0200
  [PATCH v8 22/28] x86/cpufeature: Add User-Mode Instruction Prevention definitions Ricardo Neri <ricardo.neri-calderon@linux.intel.com> - 2017-08-19 02:40 +0200
  [PATCH v8 06/28] x86/mpx: Do not use SIB.index if its value is 100b and ModRM.mod is not 11b Ricardo Neri <ricardo.neri-calderon@linux.intel.com> - 2017-08-19 02:40 +0200
  [PATCH v8 14/28] x86/insn-eval: Add utility functions to get segment descriptor base address and limit Ricardo Neri <ricardo.neri-calderon@linux.intel.com> - 2017-08-19 02:40 +0200
  [PATCH v8 25/28] x86: Enable User-Mode Instruction Prevention Ricardo Neri <ricardo.neri-calderon@linux.intel.com> - 2017-08-19 02:40 +0200
  [PATCH v8 09/28] x86/insn-eval: Do not BUG on invalid register type Ricardo Neri <ricardo.neri-calderon@linux.intel.com> - 2017-08-19 02:40 +0200

csiph-web