Re: [v6 PATCH 11/21] insn/eval: Incorporate segment base in address computation
On Fri, 2017-04-21 at 16:55 +0200, Borislav Petkov wrote: > On Tue, Mar 07, 2017 at 04:32:44PM -0800, Ricardo Neri wrote: > > insn_get_addr_ref returns the effective address as defined by the > > Please end function names with parentheses. Will do. > > > section 3.7.5.1 Vol 1 of the Intel 64 and IA-32 Architectures Software > > Developer's Manual. In order to compute the linear address, we must add > > to the effective address the segment base address as set in the segment > > descriptor. Furthermore, the segment descriptor to use depends on the > > register that is used as the base of the effective address. The effective > > base address varies depending on whether the operand is a register or a > > memory address and on whether a SiB byte is used. > > > > In most cases, the segment base address will be 0 if the USER_DS/USER32_DS > > segment is used or if segmentation is not used. However, the base address > > is not necessarily zero if a user programs defines its own segments. This > > is possible by using a local descriptor table. > > > > Since the effective address is a signed quantity, the unsigned segment > > base address saved in a separate variable and added to the final effective > > ".. is saved..." I will correct this. Thanks and 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: [v6 PATCH 11/21] insn/eval: Incorporate segment base in address computation
On Tue, Mar 07, 2017 at 04:32:44PM -0800, Ricardo Neri wrote: > insn_get_addr_ref returns the effective address as defined by the Please end function names with parentheses. > section 3.7.5.1 Vol 1 of the Intel 64 and IA-32 Architectures Software > Developer's Manual. In order to compute the linear address, we must add > to the effective address the segment base address as set in the segment > descriptor. Furthermore, the segment descriptor to use depends on the > register that is used as the base of the effective address. The effective > base address varies depending on whether the operand is a register or a > memory address and on whether a SiB byte is used. > > In most cases, the segment base address will be 0 if the USER_DS/USER32_DS > segment is used or if segmentation is not used. However, the base address > is not necessarily zero if a user programs defines its own segments. This > is possible by using a local descriptor table. > > Since the effective address is a signed quantity, the unsigned segment > base address saved in a separate variable and added to the final effective ".. is saved..." > address. > -- 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
