X-Git-Url: https://git.kernel.dk/?a=blobdiff_plain;f=arch%2Farm64%2Fmm%2Ffault.c;h=820d47353cf0489c6c521d7f4f3f2790db25d053;hb=57f4959bad0a154aeca125b7d38d1d9471a12422;hp=92ddac1e8ca2f35b8f24028514bb761aed3591a4;hpb=cc80fe0eefbbbd7b4e32f631bb2fa639d76af075;p=linux-2.6-block.git

diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c
index 92ddac1e8ca2..820d47353cf0 100644
--- a/arch/arm64/mm/fault.c
+++ b/arch/arm64/mm/fault.c
@@ -192,6 +192,14 @@ out:
 	return fault;
 }
 
+static inline int permission_fault(unsigned int esr)
+{
+	unsigned int ec       = (esr & ESR_ELx_EC_MASK) >> ESR_ELx_EC_SHIFT;
+	unsigned int fsc_type = esr & ESR_ELx_FSC_TYPE;
+
+	return (ec == ESR_ELx_EC_DABT_CUR && fsc_type == ESR_ELx_FSC_PERM);
+}
+
 static int __kprobes do_page_fault(unsigned long addr, unsigned int esr,
 				   struct pt_regs *regs)
 {
@@ -225,12 +233,10 @@ static int __kprobes do_page_fault(unsigned long addr, unsigned int esr,
 		mm_flags |= FAULT_FLAG_WRITE;
 	}
 
-	/*
-	 * PAN bit set implies the fault happened in kernel space, but not
-	 * in the arch's user access functions.
-	 */
-	if (IS_ENABLED(CONFIG_ARM64_PAN) && (regs->pstate & PSR_PAN_BIT))
-		goto no_context;
+	if (permission_fault(esr) && (addr < USER_DS)) {
+		if (!search_exception_tables(regs->pc))
+			panic("Accessing user space memory outside uaccess.h routines");
+	}
 
 	/*
 	 * As per x86, we may deadlock here. However, since the kernel only
@@ -561,3 +567,16 @@ void cpu_enable_pan(void *__unused)
 	config_sctlr_el1(SCTLR_EL1_SPAN, 0);
 }
 #endif /* CONFIG_ARM64_PAN */
+
+#ifdef CONFIG_ARM64_UAO
+/*
+ * Kernel threads have fs=KERNEL_DS by default, and don't need to call
+ * set_fs(), devtmpfs in particular relies on this behaviour.
+ * We need to enable the feature at runtime (instead of adding it to
+ * PSR_MODE_EL1h) as the feature may not be implemented by the cpu.
+ */
+void cpu_enable_uao(void *__unused)
+{
+	asm(SET_PSTATE_UAO(1));
+}
+#endif /* CONFIG_ARM64_UAO */