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Received: from j130084.upc-j.chello.nl ([24.132.130.84] helo=noisy.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.97.1 #2 (Red Hat Linux)) id 1rwJnx-0000000FWHZ-0CDf; Mon, 15 Apr 2024 10:43:22 +0000 Received: by noisy.programming.kicks-ass.net (Postfix, from userid 1000) id ACBA530040C; Mon, 15 Apr 2024 12:43:16 +0200 (CEST) Date: Mon, 15 Apr 2024 12:43:16 +0200 From: Peter Zijlstra To: Mike Rapoport Cc: linux-kernel@vger.kernel.org, Andrew Morton , Andy Lutomirski , Arnd Bergmann , Catalin Marinas , Christoph Hellwig , Helge Deller , Lorenzo Stoakes , Luis Chamberlain , Mark Rutland , Masami Hiramatsu , Mathieu Desnoyers , Michael Ellerman , Palmer Dabbelt , Russell King , Song Liu , Steven Rostedt , Thomas Gleixner , Uladzislau Rezki , Will Deacon , bpf@vger.kernel.org, linux-arch@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org, linux-modules@vger.kernel.org, linux-parisc@vger.kernel.org, linux-riscv@lists.infradead.org, linux-trace-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, x86@kernel.org Subject: Re: [RFC PATCH 5/7] x86/module: perpare module loading for ROX allocations of text Message-ID: <20240415104316.GI40213@noisy.programming.kicks-ass.net> References: <20240411160526.2093408-1-rppt@kernel.org> <20240411160526.2093408-6-rppt@kernel.org> Precedence: bulk X-Mailing-List: linux-arch@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240411160526.2093408-6-rppt@kernel.org> On Thu, Apr 11, 2024 at 07:05:24PM +0300, Mike Rapoport wrote: > diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c > index 45a280f2161c..b4d6868df573 100644 > --- a/arch/x86/kernel/alternative.c > +++ b/arch/x86/kernel/alternative.c > @@ -504,17 +513,17 @@ void __init_or_module noinline apply_alternatives(struct alt_instr *start, > * patch if feature is *NOT* present. > */ > if (!boot_cpu_has(a->cpuid) == !(a->flags & ALT_FLAG_NOT)) { > - optimize_nops_inplace(instr, a->instrlen); > + optimize_nops_inplace(wr_instr, a->instrlen); > continue; > } > > - DPRINTK(ALT, "feat: %d*32+%d, old: (%pS (%px) len: %d), repl: (%px, len: %d) flags: 0x%x", > + DPRINTK(ALT, "feat: %d*32+%d, old: (%px (%px) len: %d), repl: (%px (%px), len: %d) flags: 0x%x", > a->cpuid >> 5, > a->cpuid & 0x1f, > - instr, instr, a->instrlen, > - replacement, a->replacementlen, a->flags); > + instr, wr_instr, a->instrlen, > + replacement, wr_replacement, a->replacementlen, a->flags); I think this, and > > - memcpy(insn_buff, replacement, a->replacementlen); > + memcpy(insn_buff, wr_replacement, a->replacementlen); > insn_buff_sz = a->replacementlen; > > if (a->flags & ALT_FLAG_DIRECT_CALL) { > @@ -528,11 +537,11 @@ void __init_or_module noinline apply_alternatives(struct alt_instr *start, > > apply_relocation(insn_buff, a->instrlen, instr, replacement, a->replacementlen); > > - DUMP_BYTES(ALT, instr, a->instrlen, "%px: old_insn: ", instr); > + DUMP_BYTES(ALT, wr_instr, a->instrlen, "%px: old_insn: ", instr); this, want to remain as is. > DUMP_BYTES(ALT, replacement, a->replacementlen, "%px: rpl_insn: ", replacement); > DUMP_BYTES(ALT, insn_buff, insn_buff_sz, "%px: final_insn: ", instr); > > - text_poke_early(instr, insn_buff, insn_buff_sz); > + text_poke_early(wr_instr, insn_buff, insn_buff_sz); > } > > kasan_enable_current(); The rationale being that we then print an address that can be correlated to the kernel image (provided one either kills kaslr or adjusts for it).