Re: [PATCH v2 24/37] arm64: mte: Add in-kernel tag fault handler
From: Catalin Marinas <catalin.marinas@arm.com>
Date: 2020-09-17 14:16:41
Also in:
linux-mm, lkml
On Tue, Sep 15, 2020 at 11:16:06PM +0200, Andrey Konovalov wrote:
quoted hunk ↗ jump to hunk
diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c index a3bd189602df..cdc23662691c 100644 --- a/arch/arm64/mm/fault.c +++ b/arch/arm64/mm/fault.c@@ -294,6 +295,18 @@ static void die_kernel_fault(const char *msg, unsigned long addr, do_exit(SIGKILL); } +static void report_tag_fault(unsigned long addr, unsigned int esr, + struct pt_regs *regs) +{ + bool is_write = ((esr & ESR_ELx_WNR) >> ESR_ELx_WNR_SHIFT) != 0; + + 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)); +} + static void __do_kernel_fault(unsigned long addr, unsigned int esr, struct pt_regs *regs) {@@ -641,10 +654,31 @@ static int do_sea(unsigned long addr, unsigned int esr, struct pt_regs *regs) return 0; } +static void do_tag_recovery(unsigned long addr, unsigned int esr, + struct pt_regs *regs) +{ + report_tag_fault(addr, esr, regs);
I'd only report this once since we expect it to be disabled lazily on the other CPUs (i.e. just use a "static bool reported" to keep track).
+ + /* + * Disable Memory Tagging Extension Tag Checking on the local CPU
Too verbose, just say MTE tag checking, people reading this code should have learnt already what MTE stands for ;).
+ * for the current EL.
+ * It will be done lazily on the other CPUs when they will hit a
+ * tag fault.
+ */
+ sysreg_clear_set(sctlr_el1, SCTLR_ELx_TCF_MASK, SCTLR_ELx_TCF_NONE);
+ isb();
+}
+
+
static int do_tag_check_fault(unsigned long addr, unsigned int esr,
struct pt_regs *regs)
{
- do_bad_area(addr, esr, regs);
+ /* The tag check fault (TCF) is per TTBR */
+ if (is_ttbr0_addr(addr))
+ do_bad_area(addr, esr, regs);
+ else
+ do_tag_recovery(addr, esr, regs);This part looks fine now. -- Catalin _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel