From cd9b594a9ef122a41bc961c330a55d87e226822f Mon Sep 17 00:00:00 2001 From: Ricardo Neri Date: Sun, 5 Nov 2017 18:27:48 -0800 Subject: x86/insn-eval: Add wrapper function for 32 and 64-bit addresses The function insn_get_addr_ref() is capable of handling only 64-bit addresses. A previous commit introduced a function to handle 32-bit addresses. Invoke these two functions from a third wrapper function that calls the appropriate routine based on the address size specified in the instruction structure (obtained by looking at the code segment default address size and the address override prefix, if present). While doing this, rename the original function insn_get_addr_ref() with the more appropriate name get_addr_ref_64(), ensure it is only used for 64-bit addresses. Also, since 64-bit addresses are not possible in 32-bit builds, provide a dummy function such case. Signed-off-by: Ricardo Neri Reviewed-by: Thomas Gleixner Cc: Adam Buchbinder Cc: Adrian Hunter Cc: Andrew Morton Cc: Andy Lutomirski Cc: Arnaldo Carvalho de Melo Cc: Borislav Petkov Cc: Borislav Petkov Cc: Brian Gerst Cc: Chen Yucong Cc: Chris Metcalf Cc: Colin Ian King Cc: Dave Hansen Cc: Denys Vlasenko Cc: Dmitry Vyukov Cc: H. Peter Anvin Cc: Huang Rui Cc: Jiri Slaby Cc: Jonathan Corbet Cc: Josh Poimboeuf Cc: Kees Cook Cc: Linus Torvalds Cc: Lorenzo Stoakes Cc: Masami Hiramatsu Cc: Michael S. Tsirkin Cc: Paolo Bonzini Cc: Paul Gortmaker Cc: Peter Zijlstra Cc: Qiaowei Ren Cc: Ravi V. Shankar Cc: Shuah Khan Cc: Thomas Garnier Cc: Tony Luck Cc: Vlastimil Babka Cc: ricardo.neri@intel.com Link: http://lkml.kernel.org/r/1509935277-22138-4-git-send-email-ricardo.neri-calderon@linux.intel.com Signed-off-by: Ingo Molnar --- arch/x86/lib/insn-eval.c | 60 ++++++++++++++++++++++++++++++++++++++++++++---- 1 file changed, 55 insertions(+), 5 deletions(-) (limited to 'arch/x86/lib/insn-eval.c') diff --git a/arch/x86/lib/insn-eval.c b/arch/x86/lib/insn-eval.c index e6cb68a4f7a4..1ac39737826b 100644 --- a/arch/x86/lib/insn-eval.c +++ b/arch/x86/lib/insn-eval.c @@ -1052,17 +1052,36 @@ out: return (void __user *)linear_addr; } -/* - * return the address being referenced be instruction - * for rm=3 returning the content of the rm reg - * for rm!=3 calculates the address using SIB and Disp +/** + * get_addr_ref_64() - Obtain a 64-bit linear address + * @insn: Instruction struct with ModRM and SIB bytes and displacement + * @regs: Structure with register values as seen when entering kernel mode + * + * This function is to be used with 64-bit address encodings to obtain the + * linear memory address referred by the instruction's ModRM, SIB, + * displacement bytes and segment base address, as applicable. + * + * Returns: + * + * Linear address referenced by instruction and registers on success. + * + * -1L on error. */ -void __user *insn_get_addr_ref(struct insn *insn, struct pt_regs *regs) +#ifndef CONFIG_X86_64 +static void __user *get_addr_ref_64(struct insn *insn, struct pt_regs *regs) +{ + return (void __user *)-1L; +} +#else +static void __user *get_addr_ref_64(struct insn *insn, struct pt_regs *regs) { unsigned long linear_addr = -1L, seg_base; int regoff, ret; long eff_addr; + if (insn->addr_bytes != 8) + goto out; + if (X86_MODRM_MOD(insn->modrm.value) == 3) { ret = get_eff_addr_reg(insn, regs, ®off, &eff_addr); if (ret) @@ -1090,3 +1109,34 @@ void __user *insn_get_addr_ref(struct insn *insn, struct pt_regs *regs) out: return (void __user *)linear_addr; } +#endif /* CONFIG_X86_64 */ + +/** + * insn_get_addr_ref() - Obtain the linear address referred by instruction + * @insn: Instruction structure containing ModRM byte and displacement + * @regs: Structure with register values as seen when entering kernel mode + * + * Obtain the linear address referred by the instruction's ModRM, SIB and + * displacement bytes, and segment base, as applicable. In protected mode, + * segment limits are enforced. + * + * Returns: + * + * Linear address referenced by instruction and registers on success. + * + * -1L on error. + */ +void __user *insn_get_addr_ref(struct insn *insn, struct pt_regs *regs) +{ + if (!insn || !regs) + return (void __user *)-1L; + + switch (insn->addr_bytes) { + case 4: + return get_addr_ref_32(insn, regs); + case 8: + return get_addr_ref_64(insn, regs); + default: + return (void __user *)-1L; + } +} -- cgit v1.2.3