This is a note to let you know that I've just added the patch titled
x86/insn-eval: Add utility functions to get segment selector
to the 4.14-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...
The filename of the patch is: x86-insn-eval-add-utility-functions-to-get-segment-selector.patch and it can be found in the queue-4.14 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.
From b0caa8c8c6bbc422bc3c32b64852d6d618f32b49 Mon Sep 17 00:00:00 2001
From: Ricardo Neri ricardo.neri-calderon@linux.intel.com Date: Fri, 27 Oct 2017 13:25:40 -0700 Subject: x86/insn-eval: Add utility functions to get segment selector
From: Ricardo Neri ricardo.neri-calderon@linux.intel.com
commit 32d0b95300db03c2b23b2ea2c94769a4a138e79d upstream.
[note, only the inat.h portion, to get objtool back in sync - gregkh]
b0caa8c8c6bbc422bc3c32b64852d6d618f32b49 Mon Sep 17 00:00:00 2001 When computing a linear address and segmentation is used, we need to know the base address of the segment involved in the computation. In most of the cases, the segment base address will be zero as in USER_DS/USER32_DS. However, it may be possible that a user space program defines its own segments via a local descriptor table. In such a case, the segment base address may not be zero. Thus, the segment base address is needed to calculate correctly the linear address.
If running in protected mode, the segment selector to be used when computing a linear address is determined by either any of segment override prefixes in the instruction or inferred from the registers involved in the computation of the effective address; in that order. Also, there are cases when the segment override prefixes shall be ignored (i.e., code segments are always selected by the CS segment register; string instructions always use the ES segment register when using rDI register as operand). In long mode, segment registers are ignored, except for FS and GS. In these two cases, base addresses are obtained from the respective MSRs.
For clarity, this process can be split into four steps (and an equal number of functions): determine if segment prefixes overrides can be used; parse the segment override prefixes, and use them if found; if not found or cannot be used, use the default segment registers associated with the operand registers. Once the segment register to use has been identified, read its value to obtain the segment selector.
The method to obtain the segment selector depends on several factors. In 32-bit builds, segment selectors are saved into a pt_regs structure when switching to kernel mode. The same is also true for virtual-8086 mode. In 64-bit builds, segmentation is mostly ignored, except when running a program in 32-bit legacy mode. In this case, CS and SS can be obtained from pt_regs. DS, ES, FS and GS can be read directly from the respective segment registers.
In order to identify the segment registers, a new set of #defines is introduced. It also includes two special identifiers. One of them indicates when the default segment register associated with instruction operands shall be used. Another one indicates that the contents of the segment register shall be ignored; this identifier is used when in long mode.
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/1509135945-13762-14-git-send-email-ricardo.neri-ca... Cc: Ingo Molnar mingo@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/x86/include/asm/inat.h | 10 ++++++++++ 1 file changed, 10 insertions(+)
--- a/arch/x86/include/asm/inat.h +++ b/arch/x86/include/asm/inat.h @@ -97,6 +97,16 @@ #define INAT_MAKE_GROUP(grp) ((grp << INAT_GRP_OFFS) | INAT_MODRM) #define INAT_MAKE_IMM(imm) (imm << INAT_IMM_OFFS)
+/* Identifiers for segment registers */ +#define INAT_SEG_REG_IGNORE 0 +#define INAT_SEG_REG_DEFAULT 1 +#define INAT_SEG_REG_CS 2 +#define INAT_SEG_REG_SS 3 +#define INAT_SEG_REG_DS 4 +#define INAT_SEG_REG_ES 5 +#define INAT_SEG_REG_FS 6 +#define INAT_SEG_REG_GS 7 + /* Attribute search APIs */ extern insn_attr_t inat_get_opcode_attribute(insn_byte_t opcode); extern int inat_get_last_prefix_id(insn_byte_t last_pfx);
Patches currently in stable-queue which might be from ricardo.neri-calderon@linux.intel.com are
queue-4.14/x86-insn-eval-add-utility-functions-to-get-segment-selector.patch