On Fri, May 05, 2017 at 11:17:06AM -0700, Ricardo Neri wrote:
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 5cab1b1..7e8c963 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 182e2ae..8b16761 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_reg_offset_modrm_rm() - Obtain register in r/m part of ModRM byte
That name needs to be synced with the function name below.
- @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)
^^^^^^^^^^^^^^^^^^^^