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charset="UTF-8" X-Rspamd-Queue-Id: 2BB541819E764 X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam05 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Thu, Aug 27, 2020 at 12:48 PM Catalin Marinas wrote: > > On Fri, Aug 14, 2020 at 07:27:14PM +0200, Andrey Konovalov wrote: > > diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c > > index c62c8ba85c0e..cf00b3942564 100644 > > --- a/arch/arm64/mm/fault.c > > +++ b/arch/arm64/mm/fault.c > > @@ -14,6 +14,7 @@ > > #include > > #include > > #include > > +#include > > #include > > #include > > #include > > @@ -314,11 +315,19 @@ static void report_tag_fault(unsigned long addr, unsigned int esr, > > { > > bool is_write = ((esr & ESR_ELx_WNR) >> ESR_ELx_WNR_SHIFT) != 0; > > > > +#ifdef CONFIG_KASAN_HW_TAGS > > + /* > > + * SAS bits aren't set for all faults reported in EL1, so we can't > > + * find out access size. > > + */ > > + kasan_report(addr, 0, is_write, regs->pc); > > +#else > > pr_alert("Memory Tagging Extension Fault in %pS\n", (void *)regs->pc); > > pr_alert(" %s at address %lx\n", is_write ? "Write" : "Read", addr); > > pr_alert(" Pointer tag: [%02x], memory tag: [%02x]\n", > > mte_get_ptr_tag(addr), > > mte_get_mem_tag((void *)addr)); > > +#endif > > } > > More dead code. So what's the point of keeping the pr_alert() introduced > earlier? CONFIG_KASAN_HW_TAGS is always on for in-kernel MTE. If MTE is > disabled, this function isn't called anyway. I was considering that we can enable in-kernel MTE without enabling CONFIG_KASAN_HW_TAGS, but perhaps this isn't what we want. I'll drop this part in v2, but then we also need to make sure that in-kernel MTE is only enabled when CONFIG_KASAN_HW_TAGS is enabled. Do we need more ifdefs in arm64 patches when we write to MTE-related registers, or does this work as is?