Re: [PATCH v7 08/26] x86/insn-eval: Add a utility function to get register offsets
On Mon, 2017-05-29 at 19:16 +0200, Borislav Petkov wrote: > 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 > > Cc: Adam Buchbinder > > Cc: Colin Ian King > > Cc: Lorenzo Stoakes > > Cc: Qiaowei Ren > > Cc: Arnaldo Carvalho de Melo > > Cc: Masami Hiramatsu > > Cc: Adrian Hunter > > Cc: Kees Cook > > Cc: Thomas Garnier > > Cc: Peter Zijlstra > > Cc: Borislav Petkov > > Cc: Dmitry Vyukov > > Cc: Ravi V. Shankar > > Cc: x...@kernel.org > > Signed-off-by: Ricardo Neri > > --- > > 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 > > > > 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. Ugh! I missed this. I will update accordingly. Thanks for the detailed review. BR, Ricardo -- To unsubscribe from this list: send the line "unsubscribe linux-msdos" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH v7 08/26] x86/insn-eval: Add a utility function to get register offsets
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 > Cc: Adam Buchbinder > Cc: Colin Ian King > Cc: Lorenzo Stoakes > Cc: Qiaowei Ren > Cc: Arnaldo Carvalho de Melo > Cc: Masami Hiramatsu > Cc: Adrian Hunter > Cc: Kees Cook > Cc: Thomas Garnier > Cc: Peter Zijlstra > Cc: Borislav Petkov > Cc: Dmitry Vyukov > Cc: Ravi V. Shankar > Cc: x...@kernel.org > Signed-off-by: Ricardo Neri > --- > 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 > > 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) -- Regards/Gruss, Boris. SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard, Graham Norton, HRB 21284 (AG Nürnberg) -- -- To unsubscribe from this list: send the line "unsubscribe linux-msdos" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
[PATCH v7 08/26] x86/insn-eval: Add a utility function to get register offsets
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 Cc: Adam Buchbinder Cc: Colin Ian King Cc: Lorenzo Stoakes Cc: Qiaowei Ren Cc: Arnaldo Carvalho de Melo Cc: Masami Hiramatsu Cc: Adrian Hunter Cc: Kees Cook Cc: Thomas Garnier Cc: Peter Zijlstra Cc: Borislav Petkov Cc: Dmitry Vyukov Cc: Ravi V. Shankar Cc: x...@kernel.org Signed-off-by: Ricardo Neri --- 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 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 + * @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 -- 2.9.3 -- To unsubscribe from this list: send the line "unsubscribe linux-msdos" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html