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2017-11-23x86/umip: Fix insn_get_code_seg_params()'s return valueBorislav Petkov1-1/+1
In order to save on redundant structs definitions insn_get_code_seg_params() was made to return two 4-bit values in a char but clang complains: arch/x86/lib/insn-eval.c:780:10: warning: implicit conversion from 'int' to 'char' changes value from 132 to -124 [-Wconstant-conversion] return INSN_CODE_SEG_PARAMS(4, 8); ~~~~~~ ^~~~~~~~~~~~~~~~~~~~~~~~~~ ./arch/x86/include/asm/insn-eval.h:16:57: note: expanded from macro 'INSN_CODE_SEG_PARAMS' #define INSN_CODE_SEG_PARAMS(oper_sz, addr_sz) (oper_sz | (addr_sz << 4)) Those two values do get picked apart afterwards the opposite way of how they were ORed so wrt to the LSByte, the return value is the same. But this function returns -EINVAL in the error case, which is an int. So make it return an int which is the native word size anyway and thus fix the clang warning. Reported-by: Kees Cook <keescook@google.com> Reported-by: Nick Desaulniers <nick.desaulniers@gmail.com> Signed-off-by: Borislav Petkov <bp@suse.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: ricardo.neri-calderon@linux.intel.com Link: https://lkml.kernel.org/r/20171123091951.1462-1-bp@alien8.de
2017-11-01x86/insn-eval: Add function to get default params of code segmentRicardo Neri1-0/+5
Obtain the default values of the address and operand sizes as specified in the D and L bits of the the segment descriptor selected by the register CS. The function can be used for both protected and long modes. For virtual-8086 mode, the default address and operand sizes are always 2 bytes. The returned parameters are encoded in a signed 8-bit data type. Auxiliar macros are provided to encode and decode such values. Improvements-by: Borislav Petkov <bp@suse.de> Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Borislav Petkov <bp@suse.de> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: ricardo.neri@intel.com Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Huang Rui <ray.huang@amd.com> Cc: Qiaowei Ren <qiaowei.ren@intel.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Kees Cook <keescook@chromium.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: "Ravi V. Shankar" <ravi.v.shankar@intel.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Brian Gerst <brgerst@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Colin Ian King <colin.king@canonical.com> Cc: Chen Yucong <slaoub@gmail.com> Cc: Adam Buchbinder <adam.buchbinder@gmail.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Thomas Garnier <thgarnie@google.com> Link: https://lkml.kernel.org/r/1509135945-13762-17-git-send-email-ricardo.neri-calderon@linux.intel.com
2017-11-01x86/insn-eval: Add utility functions to get segment descriptor base address ↵Ricardo Neri1-0/+1
and limit With segmentation, the base address of the segment is needed to compute a linear address. This base address is obtained from the applicable segment descriptor. Such segment descriptor is referenced from a segment selector. These new functions obtain the segment base and limit of the segment selector indicated by segment register index given as argument. This index is any of the INAT_SEG_REG_* family of #define's. The logic to obtain the segment selector is wrapped in the function get_segment_selector() with the inputs described above. Once the selector is known, the base address is determined. In protected mode, the selector is used to obtain the segment descriptor and then its base address. In long mode, the segment base address is zero except when FS or GS are used. In virtual-8086 mode, the base address is computed as the value of the segment selector shifted 4 positions to the left. In protected mode, segment limits are enforced. Thus, a function to determine the limit of the segment is added. Segment limits are not enforced in long or virtual-8086. For the latter, addresses are limited to 20 bits; address size will be handled when computing the linear address. Improvements-by: Borislav Petkov <bp@suse.de> Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Borislav Petkov <bp@suse.de> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: ricardo.neri@intel.com Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Huang Rui <ray.huang@amd.com> Cc: Qiaowei Ren <qiaowei.ren@intel.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Kees Cook <keescook@chromium.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: "Ravi V. Shankar" <ravi.v.shankar@intel.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Brian Gerst <brgerst@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Colin Ian King <colin.king@canonical.com> Cc: Chen Yucong <slaoub@gmail.com> Cc: Adam Buchbinder <adam.buchbinder@gmail.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Thomas Garnier <thgarnie@google.com> Link: https://lkml.kernel.org/r/1509135945-13762-16-git-send-email-ricardo.neri-calderon@linux.intel.com
2017-11-01x86/insn-eval: Add a utility function to get register offsetsRicardo Neri1-0/+1
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. Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Borislav Petkov <bp@suse.de> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: ricardo.neri@intel.com Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Huang Rui <ray.huang@amd.com> Cc: Qiaowei Ren <qiaowei.ren@intel.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Kees Cook <keescook@chromium.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: "Ravi V. Shankar" <ravi.v.shankar@intel.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Brian Gerst <brgerst@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Colin Ian King <colin.king@canonical.com> Cc: Chen Yucong <slaoub@gmail.com> Cc: Adam Buchbinder <adam.buchbinder@gmail.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Thomas Garnier <thgarnie@google.com> Link: https://lkml.kernel.org/r/1509135945-13762-12-git-send-email-ricardo.neri-calderon@linux.intel.com
2017-11-01x86/mpx, x86/insn: Relocate insn util functions to a new insn-eval fileRicardo Neri1-0/+16
Other kernel submodules can benefit from using the utility functions defined in mpx.c to obtain the addresses and values of operands contained in the general purpose registers. An instance of this is the emulation code used for instructions protected by the Intel User-Mode Instruction Prevention feature. Thus, these functions are relocated to a new insn-eval.c file. The reason to not relocate these utilities into insn.c is that the latter solely analyses instructions given by a struct insn without any knowledge of the meaning of the values of instruction operands. This new utility insn- eval.c aims to be used to resolve userspace linear addresses based on the contents of the instruction operands as well as the contents of pt_regs structure. These utilities come with a separate header. This is to avoid taking insn.c out of sync from the instructions decoders under tools/obj and tools/perf. This also avoids adding cumbersome #ifdef's for the #include'd files required to decode instructions in a kernel context. Functions are simply relocated. There are not functional or indentation changes. Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Borislav Petkov <bp@suse.de> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: ricardo.neri@intel.com Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Huang Rui <ray.huang@amd.com> Cc: Qiaowei Ren <qiaowei.ren@intel.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Kees Cook <keescook@chromium.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: "Ravi V. Shankar" <ravi.v.shankar@intel.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Brian Gerst <brgerst@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Colin Ian King <colin.king@canonical.com> Cc: Chen Yucong <slaoub@gmail.com> Cc: Adam Buchbinder <adam.buchbinder@gmail.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Thomas Garnier <thgarnie@google.com> Link: https://lkml.kernel.org/r/1509135945-13762-10-git-send-email-ricardo.neri-calderon@linux.intel.com