Merge branch 'for-next/errata' into for-next/core

Rework of the workaround for Cortex-A76 erratum 1463225 to fit in better
with the ongoing exception entry cleanups and changes to the detection
code for Cortex-A55 erratum 1024718 since it applies to all revisions of
the silicon.

* for-next/errata:
  arm64: entry: consolidate Cortex-A76 erratum 1463225 workaround
  arm64: Extend workaround for erratum 1024718 to all versions of Cortex-A55

arch/arm64/Kconfig

@@ -522,7 +522,7 @@ config ARM64_ERRATUM_1024718
 	help
 	  This option adds a workaround for ARM Cortex-A55 Erratum 1024718.
 
-	  Affected Cortex-A55 cores (r0p0, r0p1, r1p0) could cause incorrect
+	  Affected Cortex-A55 cores (all revisions) could cause incorrect
 	  update of the hardware dirty bit when the DBM/AP bits are updated
 	  without a break-before-make. The workaround is to disable the usage
 	  of hardware DBM locally on the affected cores. CPUs not affected by

arch/arm64/kernel/cpu_errata.c

@@ -107,8 +107,6 @@ cpu_enable_trap_ctr_access(const struct arm64_cpu_capabilities *cap)
 }
 
 #ifdef CONFIG_ARM64_ERRATUM_1463225
-DEFINE_PER_CPU(int, __in_cortex_a76_erratum_1463225_wa);
-
 static bool
 has_cortex_a76_erratum_1463225(const struct arm64_cpu_capabilities *entry,
 			       int scope)

arch/arm64/kernel/cpufeature.c

@@ -1506,7 +1506,7 @@ static bool cpu_has_broken_dbm(void)
 	/* List of CPUs which have broken DBM support. */
 	static const struct midr_range cpus[] = {
 #ifdef CONFIG_ARM64_ERRATUM_1024718
-		MIDR_RANGE(MIDR_CORTEX_A55, 0, 0, 1, 0),  // A55 r0p0 -r1p0
+		MIDR_ALL_VERSIONS(MIDR_CORTEX_A55),
 		/* Kryo4xx Silver (rdpe => r1p0) */
 		MIDR_REV(MIDR_QCOM_KRYO_4XX_SILVER, 0xd, 0xe),
 #endif

arch/arm64/kernel/entry-common.c

@@ -109,6 +109,55 @@ asmlinkage void noinstr exit_el1_irq_or_nmi(struct pt_regs *regs)
 		exit_to_kernel_mode(regs);
 }
 
+#ifdef CONFIG_ARM64_ERRATUM_1463225
+static DEFINE_PER_CPU(int, __in_cortex_a76_erratum_1463225_wa);
+
+static void cortex_a76_erratum_1463225_svc_handler(void)
+{
+	u32 reg, val;
+
+	if (!unlikely(test_thread_flag(TIF_SINGLESTEP)))
+		return;
+
+	if (!unlikely(this_cpu_has_cap(ARM64_WORKAROUND_1463225)))
+		return;
+
+	__this_cpu_write(__in_cortex_a76_erratum_1463225_wa, 1);
+	reg = read_sysreg(mdscr_el1);
+	val = reg | DBG_MDSCR_SS | DBG_MDSCR_KDE;
+	write_sysreg(val, mdscr_el1);
+	asm volatile("msr daifclr, #8");
+	isb();
+
+	/* We will have taken a single-step exception by this point */
+
+	write_sysreg(reg, mdscr_el1);
+	__this_cpu_write(__in_cortex_a76_erratum_1463225_wa, 0);
+}
+
+static bool cortex_a76_erratum_1463225_debug_handler(struct pt_regs *regs)
+{
+	if (!__this_cpu_read(__in_cortex_a76_erratum_1463225_wa))
+		return false;
+
+	/*
+	 * We've taken a dummy step exception from the kernel to ensure
+	 * that interrupts are re-enabled on the syscall path. Return back
+	 * to cortex_a76_erratum_1463225_svc_handler() with debug exceptions
+	 * masked so that we can safely restore the mdscr and get on with
+	 * handling the syscall.
+	 */
+	regs->pstate |= PSR_D_BIT;
+	return true;
+}
+#else /* CONFIG_ARM64_ERRATUM_1463225 */
+static void cortex_a76_erratum_1463225_svc_handler(void) { }
+static bool cortex_a76_erratum_1463225_debug_handler(struct pt_regs *regs)
+{
+	return false;
+}
+#endif /* CONFIG_ARM64_ERRATUM_1463225 */
+
 static void noinstr el1_abort(struct pt_regs *regs, unsigned long esr)
 {
 	unsigned long far = read_sysreg(far_el1);
@@ -186,7 +235,8 @@ static void noinstr el1_dbg(struct pt_regs *regs, unsigned long esr)
 		gic_write_pmr(GIC_PRIO_IRQON | GIC_PRIO_PSR_I_SET);
 
 	arm64_enter_el1_dbg(regs);
-	do_debug_exception(far, esr, regs);
+	if (!cortex_a76_erratum_1463225_debug_handler(regs))
+		do_debug_exception(far, esr, regs);
 	arm64_exit_el1_dbg(regs);
 }
 
@@ -362,6 +412,7 @@ static void noinstr el0_svc(struct pt_regs *regs)
 		gic_write_pmr(GIC_PRIO_IRQON | GIC_PRIO_PSR_I_SET);
 
 	enter_from_user_mode();
+	cortex_a76_erratum_1463225_svc_handler();
 	do_el0_svc(regs);
 }
 
@@ -439,6 +490,7 @@ static void noinstr el0_svc_compat(struct pt_regs *regs)
 		gic_write_pmr(GIC_PRIO_IRQON | GIC_PRIO_PSR_I_SET);
 
 	enter_from_user_mode();
+	cortex_a76_erratum_1463225_svc_handler();
 	do_el0_svc_compat(regs);
 }
 

arch/arm64/kernel/syscall.c

@@ -65,35 +65,6 @@ static inline bool has_syscall_work(unsigned long flags)
 int syscall_trace_enter(struct pt_regs *regs);
 void syscall_trace_exit(struct pt_regs *regs);
 
-#ifdef CONFIG_ARM64_ERRATUM_1463225
-DECLARE_PER_CPU(int, __in_cortex_a76_erratum_1463225_wa);
-
-static void cortex_a76_erratum_1463225_svc_handler(void)
-{
-	u32 reg, val;
-
-	if (!unlikely(test_thread_flag(TIF_SINGLESTEP)))
-		return;
-
-	if (!unlikely(this_cpu_has_cap(ARM64_WORKAROUND_1463225)))
-		return;
-
-	__this_cpu_write(__in_cortex_a76_erratum_1463225_wa, 1);
-	reg = read_sysreg(mdscr_el1);
-	val = reg | DBG_MDSCR_SS | DBG_MDSCR_KDE;
-	write_sysreg(val, mdscr_el1);
-	asm volatile("msr daifclr, #8");
-	isb();
-
-	/* We will have taken a single-step exception by this point */
-
-	write_sysreg(reg, mdscr_el1);
-	__this_cpu_write(__in_cortex_a76_erratum_1463225_wa, 0);
-}
-#else
-static void cortex_a76_erratum_1463225_svc_handler(void) { }
-#endif /* CONFIG_ARM64_ERRATUM_1463225 */
-
 static void el0_svc_common(struct pt_regs *regs, int scno, int sc_nr,
 			   const syscall_fn_t syscall_table[])
 {
@@ -120,7 +91,6 @@ static void el0_svc_common(struct pt_regs *regs, int scno, int sc_nr,
 	 * (Similarly for HVC and SMC elsewhere.)
 	 */
 
-	cortex_a76_erratum_1463225_svc_handler();
 	local_daif_restore(DAIF_PROCCTX);
 
 	if (flags & _TIF_MTE_ASYNC_FAULT) {

arch/arm64/mm/fault.c

@@ -874,44 +874,12 @@ static void debug_exception_exit(struct pt_regs *regs)
 }
 NOKPROBE_SYMBOL(debug_exception_exit);
 
-#ifdef CONFIG_ARM64_ERRATUM_1463225
-DECLARE_PER_CPU(int, __in_cortex_a76_erratum_1463225_wa);
-
-static int cortex_a76_erratum_1463225_debug_handler(struct pt_regs *regs)
-{
-	if (user_mode(regs))
-		return 0;
-
-	if (!__this_cpu_read(__in_cortex_a76_erratum_1463225_wa))
-		return 0;
-
-	/*
-	 * We've taken a dummy step exception from the kernel to ensure
-	 * that interrupts are re-enabled on the syscall path. Return back
-	 * to cortex_a76_erratum_1463225_svc_handler() with debug exceptions
-	 * masked so that we can safely restore the mdscr and get on with
-	 * handling the syscall.
-	 */
-	regs->pstate |= PSR_D_BIT;
-	return 1;
-}
-#else
-static int cortex_a76_erratum_1463225_debug_handler(struct pt_regs *regs)
-{
-	return 0;
-}
-#endif /* CONFIG_ARM64_ERRATUM_1463225 */
-NOKPROBE_SYMBOL(cortex_a76_erratum_1463225_debug_handler);
-
 void do_debug_exception(unsigned long addr_if_watchpoint, unsigned int esr,
 			struct pt_regs *regs)
 {
 	const struct fault_info *inf = esr_to_debug_fault_info(esr);
 	unsigned long pc = instruction_pointer(regs);
 
-	if (cortex_a76_erratum_1463225_debug_handler(regs))
-		return;
-
 	debug_exception_enter(regs);
 
 	if (user_mode(regs) && !is_ttbr0_addr(pc))