Merge branch 'for-next/entry-s-to-c' into for-next/core

Move the synchronous exception paths from entry.S into a C file to
improve the code readability.

* for-next/entry-s-to-c:
  arm64: entry-common: don't touch daif before bp-hardening
  arm64: Remove asmlinkage from updated functions
  arm64: entry: convert el0_sync to C
  arm64: entry: convert el1_sync to C
  arm64: add local_daif_inherit()
  arm64: Add prototypes for functions called by entry.S
  arm64: remove __exception annotations

arch/arm64/include/asm/asm-uaccess.h

@@ -74,13 +74,4 @@ alternative_if ARM64_ALT_PAN_NOT_UAO
 	SET_PSTATE_PAN(0)
 alternative_else_nop_endif
 	.endm
-
-/*
- * Remove the address tag from a virtual address, if present.
- */
-	.macro	untagged_addr, dst, addr
-	sbfx	\dst, \addr, #0, #56
-	and	\dst, \dst, \addr
-	.endm
-
 #endif

arch/arm64/include/asm/daifflags.h

@@ -9,6 +9,7 @@
 
 #include <asm/arch_gicv3.h>
 #include <asm/cpufeature.h>
+#include <asm/ptrace.h>
 
 #define DAIF_PROCCTX		0
 #define DAIF_PROCCTX_NOIRQ	PSR_I_BIT
@@ -109,4 +110,19 @@ static inline void local_daif_restore(unsigned long flags)
 		trace_hardirqs_off();
 }
 
+/*
+ * Called by synchronous exception handlers to restore the DAIF bits that were
+ * modified by taking an exception.
+ */
+static inline void local_daif_inherit(struct pt_regs *regs)
+{
+	unsigned long flags = regs->pstate & DAIF_MASK;
+
+	/*
+	 * We can't use local_daif_restore(regs->pstate) here as
+	 * system_has_prio_mask_debugging() won't restore the I bit if it can
+	 * use the pmr instead.
+	 */
+	write_sysreg(flags, daif);
+}
 #endif

arch/arm64/include/asm/exception.h

@@ -8,14 +8,15 @@
 #define __ASM_EXCEPTION_H
 
 #include <asm/esr.h>
+#include <asm/kprobes.h>
+#include <asm/ptrace.h>
 
 #include <linux/interrupt.h>
 
-#define __exception	__attribute__((section(".exception.text")))
 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 #define __exception_irq_entry	__irq_entry
 #else
-#define __exception_irq_entry	__exception
+#define __exception_irq_entry	__kprobes
 #endif
 
 static inline u32 disr_to_esr(u64 disr)
@@ -31,5 +32,22 @@ static inline u32 disr_to_esr(u64 disr)
 }
 
 asmlinkage void enter_from_user_mode(void);
+void do_mem_abort(unsigned long addr, unsigned int esr, struct pt_regs *regs);
+void do_sp_pc_abort(unsigned long addr, unsigned int esr, struct pt_regs *regs);
+void do_undefinstr(struct pt_regs *regs);
+asmlinkage void bad_mode(struct pt_regs *regs, int reason, unsigned int esr);
+void do_debug_exception(unsigned long addr_if_watchpoint, unsigned int esr,
+			struct pt_regs *regs);
+void do_fpsimd_acc(unsigned int esr, struct pt_regs *regs);
+void do_sve_acc(unsigned int esr, struct pt_regs *regs);
+void do_fpsimd_exc(unsigned int esr, struct pt_regs *regs);
+void do_sysinstr(unsigned int esr, struct pt_regs *regs);
+void do_sp_pc_abort(unsigned long addr, unsigned int esr, struct pt_regs *regs);
+void bad_el0_sync(struct pt_regs *regs, int reason, unsigned int esr);
+void do_cp15instr(unsigned int esr, struct pt_regs *regs);
+void el0_svc_handler(struct pt_regs *regs);
+void el0_svc_compat_handler(struct pt_regs *regs);
+void do_el0_ia_bp_hardening(unsigned long addr,  unsigned int esr,
+			    struct pt_regs *regs);
 
 #endif	/* __ASM_EXCEPTION_H */

arch/arm64/include/asm/processor.h

@@ -26,10 +26,12 @@
 #include <linux/init.h>
 #include <linux/stddef.h>
 #include <linux/string.h>
+#include <linux/thread_info.h>
 
 #include <asm/alternative.h>
 #include <asm/cpufeature.h>
 #include <asm/hw_breakpoint.h>
+#include <asm/kasan.h>
 #include <asm/lse.h>
 #include <asm/pgtable-hwdef.h>
 #include <asm/pointer_auth.h>
@@ -214,6 +216,18 @@ static inline void start_thread(struct pt_regs *regs, unsigned long pc,
 	regs->sp = sp;
 }
 
+static inline bool is_ttbr0_addr(unsigned long addr)
+{
+	/* entry assembly clears tags for TTBR0 addrs */
+	return addr < TASK_SIZE;
+}
+
+static inline bool is_ttbr1_addr(unsigned long addr)
+{
+	/* TTBR1 addresses may have a tag if KASAN_SW_TAGS is in use */
+	return arch_kasan_reset_tag(addr) >= PAGE_OFFSET;
+}
+
 #ifdef CONFIG_COMPAT
 static inline void compat_start_thread(struct pt_regs *regs, unsigned long pc,
 				       unsigned long sp)

arch/arm64/include/asm/traps.h

@@ -42,16 +42,6 @@ static inline int __in_irqentry_text(unsigned long ptr)
 	       ptr < (unsigned long)&__irqentry_text_end;
 }
 
-static inline int in_exception_text(unsigned long ptr)
-{
-	int in;
-
-	in = ptr >= (unsigned long)&__exception_text_start &&
-	     ptr < (unsigned long)&__exception_text_end;
-
-	return in ? : __in_irqentry_text(ptr);
-}
-
 static inline int in_entry_text(unsigned long ptr)
 {
 	return ptr >= (unsigned long)&__entry_text_start &&

arch/arm64/kernel/Makefile

@@ -13,9 +13,9 @@ CFLAGS_REMOVE_return_address.o = $(CC_FLAGS_FTRACE)
 
 # Object file lists.
 obj-y			:= debug-monitors.o entry.o irq.o fpsimd.o		\
-			   entry-fpsimd.o process.o ptrace.o setup.o signal.o	\
-			   sys.o stacktrace.o time.o traps.o io.o vdso.o	\
-			   hyp-stub.o psci.o cpu_ops.o insn.o	\
+			   entry-common.o entry-fpsimd.o process.o ptrace.o	\
+			   setup.o signal.o sys.o stacktrace.o time.o traps.o	\
+			   io.o vdso.o hyp-stub.o psci.o cpu_ops.o insn.o	\
 			   return_address.o cpuinfo.o cpu_errata.o		\
 			   cpufeature.o alternative.o cacheinfo.o		\
 			   smp.o smp_spin_table.o topology.o smccc-call.o	\

arch/arm64/kernel/entry-common.c

+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Exception handling code
+ *
+ * Copyright (C) 2019 ARM Ltd.
+ */
+
+#include <linux/context_tracking.h>
+#include <linux/ptrace.h>
+#include <linux/thread_info.h>
+
+#include <asm/cpufeature.h>
+#include <asm/daifflags.h>
+#include <asm/esr.h>
+#include <asm/exception.h>
+#include <asm/kprobes.h>
+#include <asm/mmu.h>
+#include <asm/sysreg.h>
+
+static void notrace el1_abort(struct pt_regs *regs, unsigned long esr)
+{
+	unsigned long far = read_sysreg(far_el1);
+
+	local_daif_inherit(regs);
+	far = untagged_addr(far);
+	do_mem_abort(far, esr, regs);
+}
+NOKPROBE_SYMBOL(el1_abort);
+
+static void notrace el1_pc(struct pt_regs *regs, unsigned long esr)
+{
+	unsigned long far = read_sysreg(far_el1);
+
+	local_daif_inherit(regs);
+	do_sp_pc_abort(far, esr, regs);
+}
+NOKPROBE_SYMBOL(el1_pc);
+
+static void el1_undef(struct pt_regs *regs)
+{
+	local_daif_inherit(regs);
+	do_undefinstr(regs);
+}
+NOKPROBE_SYMBOL(el1_undef);
+
+static void el1_inv(struct pt_regs *regs, unsigned long esr)
+{
+	local_daif_inherit(regs);
+	bad_mode(regs, 0, esr);
+}
+NOKPROBE_SYMBOL(el1_inv);
+
+static void notrace el1_dbg(struct pt_regs *regs, unsigned long esr)
+{
+	unsigned long far = read_sysreg(far_el1);
+
+	/*
+	 * The CPU masked interrupts, and we are leaving them masked during
+	 * do_debug_exception(). Update PMR as if we had called
+	 * local_mask_daif().
+	 */
+	if (system_uses_irq_prio_masking())
+		gic_write_pmr(GIC_PRIO_IRQON | GIC_PRIO_PSR_I_SET);
+
+	do_debug_exception(far, esr, regs);
+}
+NOKPROBE_SYMBOL(el1_dbg);
+
+asmlinkage void notrace el1_sync_handler(struct pt_regs *regs)
+{
+	unsigned long esr = read_sysreg(esr_el1);
+
+	switch (ESR_ELx_EC(esr)) {
+	case ESR_ELx_EC_DABT_CUR:
+	case ESR_ELx_EC_IABT_CUR:
+		el1_abort(regs, esr);
+		break;
+	/*
+	 * We don't handle ESR_ELx_EC_SP_ALIGN, since we will have hit a
+	 * recursive exception when trying to push the initial pt_regs.
+	 */
+	case ESR_ELx_EC_PC_ALIGN:
+		el1_pc(regs, esr);
+		break;
+	case ESR_ELx_EC_SYS64:
+	case ESR_ELx_EC_UNKNOWN:
+		el1_undef(regs);
+		break;
+	case ESR_ELx_EC_BREAKPT_CUR:
+	case ESR_ELx_EC_SOFTSTP_CUR:
+	case ESR_ELx_EC_WATCHPT_CUR:
+	case ESR_ELx_EC_BRK64:
+		el1_dbg(regs, esr);
+		break;
+	default:
+		el1_inv(regs, esr);
+	};
+}
+NOKPROBE_SYMBOL(el1_sync_handler);
+
+static void notrace el0_da(struct pt_regs *regs, unsigned long esr)
+{
+	unsigned long far = read_sysreg(far_el1);
+
+	user_exit_irqoff();
+	local_daif_restore(DAIF_PROCCTX);
+	far = untagged_addr(far);
+	do_mem_abort(far, esr, regs);
+}
+NOKPROBE_SYMBOL(el0_da);
+
+static void notrace el0_ia(struct pt_regs *regs, unsigned long esr)
+{
+	unsigned long far = read_sysreg(far_el1);
+
+	/*
+	 * We've taken an instruction abort from userspace and not yet
+	 * re-enabled IRQs. If the address is a kernel address, apply
+	 * BP hardening prior to enabling IRQs and pre-emption.
+	 */
+	if (!is_ttbr0_addr(far))
+		arm64_apply_bp_hardening();
+
+	user_exit_irqoff();
+	local_daif_restore(DAIF_PROCCTX);
+	do_mem_abort(far, esr, regs);
+}
+NOKPROBE_SYMBOL(el0_ia);
+
+static void notrace el0_fpsimd_acc(struct pt_regs *regs, unsigned long esr)
+{
+	user_exit_irqoff();
+	local_daif_restore(DAIF_PROCCTX);
+	do_fpsimd_acc(esr, regs);
+}
+NOKPROBE_SYMBOL(el0_fpsimd_acc);
+
+static void notrace el0_sve_acc(struct pt_regs *regs, unsigned long esr)
+{
+	user_exit_irqoff();
+	local_daif_restore(DAIF_PROCCTX);
+	do_sve_acc(esr, regs);
+}
+NOKPROBE_SYMBOL(el0_sve_acc);
+
+static void notrace el0_fpsimd_exc(struct pt_regs *regs, unsigned long esr)
+{
+	user_exit_irqoff();
+	local_daif_restore(DAIF_PROCCTX);
+	do_fpsimd_exc(esr, regs);
+}
+NOKPROBE_SYMBOL(el0_fpsimd_exc);
+
+static void notrace el0_sys(struct pt_regs *regs, unsigned long esr)
+{
+	user_exit_irqoff();
+	local_daif_restore(DAIF_PROCCTX);
+	do_sysinstr(esr, regs);
+}
+NOKPROBE_SYMBOL(el0_sys);
+
+static void notrace el0_pc(struct pt_regs *regs, unsigned long esr)
+{
+	unsigned long far = read_sysreg(far_el1);
+
+	if (!is_ttbr0_addr(instruction_pointer(regs)))
+		arm64_apply_bp_hardening();
+
+	user_exit_irqoff();
+	local_daif_restore(DAIF_PROCCTX);
+	do_sp_pc_abort(far, esr, regs);
+}
+NOKPROBE_SYMBOL(el0_pc);
+
+static void notrace el0_sp(struct pt_regs *regs, unsigned long esr)
+{
+	user_exit_irqoff();
+	local_daif_restore(DAIF_PROCCTX_NOIRQ);
+	do_sp_pc_abort(regs->sp, esr, regs);
+}
+NOKPROBE_SYMBOL(el0_sp);
+
+static void notrace el0_undef(struct pt_regs *regs)
+{
+	user_exit_irqoff();
+	local_daif_restore(DAIF_PROCCTX);
+	do_undefinstr(regs);
+}
+NOKPROBE_SYMBOL(el0_undef);
+
+static void notrace el0_inv(struct pt_regs *regs, unsigned long esr)
+{
+	user_exit_irqoff();
+	local_daif_restore(DAIF_PROCCTX);
+	bad_el0_sync(regs, 0, esr);
+}
+NOKPROBE_SYMBOL(el0_inv);
+
+static void notrace el0_dbg(struct pt_regs *regs, unsigned long esr)
+{
+	/* Only watchpoints write FAR_EL1, otherwise its UNKNOWN */
+	unsigned long far = read_sysreg(far_el1);
+
+	if (system_uses_irq_prio_masking())
+		gic_write_pmr(GIC_PRIO_IRQON | GIC_PRIO_PSR_I_SET);
+
+	user_exit_irqoff();
+	do_debug_exception(far, esr, regs);
+	local_daif_restore(DAIF_PROCCTX_NOIRQ);
+}
+NOKPROBE_SYMBOL(el0_dbg);
+
+static void notrace el0_svc(struct pt_regs *regs)
+{
+	if (system_uses_irq_prio_masking())
+		gic_write_pmr(GIC_PRIO_IRQON | GIC_PRIO_PSR_I_SET);
+
+	el0_svc_handler(regs);
+}
+NOKPROBE_SYMBOL(el0_svc);
+
+asmlinkage void notrace el0_sync_handler(struct pt_regs *regs)
+{
+	unsigned long esr = read_sysreg(esr_el1);
+
+	switch (ESR_ELx_EC(esr)) {
+	case ESR_ELx_EC_SVC64:
+		el0_svc(regs);
+		break;
+	case ESR_ELx_EC_DABT_LOW:
+		el0_da(regs, esr);
+		break;
+	case ESR_ELx_EC_IABT_LOW:
+		el0_ia(regs, esr);
+		break;
+	case ESR_ELx_EC_FP_ASIMD:
+		el0_fpsimd_acc(regs, esr);
+		break;
+	case ESR_ELx_EC_SVE:
+		el0_sve_acc(regs, esr);
+		break;
+	case ESR_ELx_EC_FP_EXC64:
+		el0_fpsimd_exc(regs, esr);
+		break;
+	case ESR_ELx_EC_SYS64:
+	case ESR_ELx_EC_WFx:
+		el0_sys(regs, esr);
+		break;
+	case ESR_ELx_EC_SP_ALIGN:
+		el0_sp(regs, esr);
+		break;
+	case ESR_ELx_EC_PC_ALIGN:
+		el0_pc(regs, esr);
+		break;
+	case ESR_ELx_EC_UNKNOWN:
+		el0_undef(regs);
+		break;
+	case ESR_ELx_EC_BREAKPT_LOW:
+	case ESR_ELx_EC_SOFTSTP_LOW:
+	case ESR_ELx_EC_WATCHPT_LOW:
+	case ESR_ELx_EC_BRK64:
+		el0_dbg(regs, esr);
+		break;
+	default:
+		el0_inv(regs, esr);
+	}
+}
+NOKPROBE_SYMBOL(el0_sync_handler);
+
+#ifdef CONFIG_COMPAT
+static void notrace el0_cp15(struct pt_regs *regs, unsigned long esr)
+{
+	user_exit_irqoff();
+	local_daif_restore(DAIF_PROCCTX);
+	do_cp15instr(esr, regs);
+}
+NOKPROBE_SYMBOL(el0_cp15);
+
+static void notrace el0_svc_compat(struct pt_regs *regs)
+{
+	if (system_uses_irq_prio_masking())
+		gic_write_pmr(GIC_PRIO_IRQON | GIC_PRIO_PSR_I_SET);
+
+	el0_svc_compat_handler(regs);
+}
+NOKPROBE_SYMBOL(el0_svc_compat);
+
+asmlinkage void notrace el0_sync_compat_handler(struct pt_regs *regs)
+{
+	unsigned long esr = read_sysreg(esr_el1);
+
+	switch (ESR_ELx_EC(esr)) {
+	case ESR_ELx_EC_SVC32:
+		el0_svc_compat(regs);
+		break;
+	case ESR_ELx_EC_DABT_LOW:
+		el0_da(regs, esr);
+		break;
+	case ESR_ELx_EC_IABT_LOW:
+		el0_ia(regs, esr);
+		break;
+	case ESR_ELx_EC_FP_ASIMD:
+		el0_fpsimd_acc(regs, esr);
+		break;
+	case ESR_ELx_EC_FP_EXC32:
+		el0_fpsimd_exc(regs, esr);
+		break;
+	case ESR_ELx_EC_PC_ALIGN:
+		el0_pc(regs, esr);
+		break;
+	case ESR_ELx_EC_UNKNOWN:
+	case ESR_ELx_EC_CP14_MR:
+	case ESR_ELx_EC_CP14_LS:
+	case ESR_ELx_EC_CP14_64:
+		el0_undef(regs);
+		break;
+	case ESR_ELx_EC_CP15_32:
+	case ESR_ELx_EC_CP15_64:
+		el0_cp15(regs, esr);
+		break;
+	case ESR_ELx_EC_BREAKPT_LOW:
+	case ESR_ELx_EC_SOFTSTP_LOW:
+	case ESR_ELx_EC_WATCHPT_LOW:
+	case ESR_ELx_EC_BKPT32:
+		el0_dbg(regs, esr);
+		break;
+	default:
+		el0_inv(regs, esr);
+	}
+}
+NOKPROBE_SYMBOL(el0_sync_compat_handler);
+#endif /* CONFIG_COMPAT */

arch/arm64/kernel/entry.S

@@ -578,76 +578,9 @@ ENDPROC(el1_error_invalid)
 	.align	6
 el1_sync:
 	kernel_entry 1
-	mrs	x1, esr_el1			// read the syndrome register
-	lsr	x24, x1, #ESR_ELx_EC_SHIFT	// exception class
-	cmp	x24, #ESR_ELx_EC_DABT_CUR	// data abort in EL1
-	b.eq	el1_da
-	cmp	x24, #ESR_ELx_EC_IABT_CUR	// instruction abort in EL1
-	b.eq	el1_ia
-	cmp	x24, #ESR_ELx_EC_SYS64		// configurable trap
-	b.eq	el1_undef
-	cmp	x24, #ESR_ELx_EC_PC_ALIGN	// pc alignment exception
-	b.eq	el1_pc
-	cmp	x24, #ESR_ELx_EC_UNKNOWN	// unknown exception in EL1
-	b.eq	el1_undef
-	cmp	x24, #ESR_ELx_EC_BREAKPT_CUR	// debug exception in EL1
-	b.ge	el1_dbg
-	b	el1_inv
-
-el1_ia:
-	/*
-	 * Fall through to the Data abort case
-	 */
-el1_da:
-	/*
-	 * Data abort handling
-	 */
-	mrs	x3, far_el1
-	inherit_daif	pstate=x23, tmp=x2
-	untagged_addr	x0, x3
-	mov	x2, sp				// struct pt_regs
-	bl	do_mem_abort
-
-	kernel_exit 1
-el1_pc:
-	/*
-	 * PC alignment exception handling. We don't handle SP alignment faults,
-	 * since we will have hit a recursive exception when trying to push the
-	 * initial pt_regs.
-	 */
-	mrs	x0, far_el1
-	inherit_daif	pstate=x23, tmp=x2
-	mov	x2, sp
-	bl	do_sp_pc_abort
-	ASM_BUG()
-el1_undef:
-	/*
-	 * Undefined instruction
-	 */
-	inherit_daif	pstate=x23, tmp=x2
 	mov	x0, sp
-	bl	do_undefinstr
+	bl	el1_sync_handler
 	kernel_exit 1
-el1_dbg:
-	/*
-	 * Debug exception handling
-	 */
-	cmp	x24, #ESR_ELx_EC_BRK64		// if BRK64
-	cinc	x24, x24, eq			// set bit '0'
-	tbz	x24, #0, el1_inv		// EL1 only
-	gic_prio_kentry_setup tmp=x3
-	mrs	x0, far_el1
-	mov	x2, sp				// struct pt_regs
-	bl	do_debug_exception
-	kernel_exit 1
-el1_inv:
-	// TODO: add support for undefined instructions in kernel mode
-	inherit_daif	pstate=x23, tmp=x2
-	mov	x0, sp
-	mov	x2, x1
-	mov	x1, #BAD_SYNC
-	bl	bad_mode
-	ASM_BUG()
 ENDPROC(el1_sync)
 
 	.align	6
@@ -714,71 +647,18 @@ ENDPROC(el1_irq)
 	.align	6
 el0_sync:
 	kernel_entry 0
-	mrs	x25, esr_el1			// read the syndrome register
-	lsr	x24, x25, #ESR_ELx_EC_SHIFT	// exception class
-	cmp	x24, #ESR_ELx_EC_SVC64		// SVC in 64-bit state
-	b.eq	el0_svc
-	cmp	x24, #ESR_ELx_EC_DABT_LOW	// data abort in EL0
-	b.eq	el0_da
-	cmp	x24, #ESR_ELx_EC_IABT_LOW	// instruction abort in EL0
-	b.eq	el0_ia
-	cmp	x24, #ESR_ELx_EC_FP_ASIMD	// FP/ASIMD access
-	b.eq	el0_fpsimd_acc
-	cmp	x24, #ESR_ELx_EC_SVE		// SVE access
-	b.eq	el0_sve_acc
-	cmp	x24, #ESR_ELx_EC_FP_EXC64	// FP/ASIMD exception
-	b.eq	el0_fpsimd_exc
-	cmp	x24, #ESR_ELx_EC_SYS64		// configurable trap
-	ccmp	x24, #ESR_ELx_EC_WFx, #4, ne
-	b.eq	el0_sys
-	cmp	x24, #ESR_ELx_EC_SP_ALIGN	// stack alignment exception
-	b.eq	el0_sp
-	cmp	x24, #ESR_ELx_EC_PC_ALIGN	// pc alignment exception
-	b.eq	el0_pc
-	cmp	x24, #ESR_ELx_EC_UNKNOWN	// unknown exception in EL0
-	b.eq	el0_undef
-	cmp	x24, #ESR_ELx_EC_BREAKPT_LOW	// debug exception in EL0
-	b.ge	el0_dbg
-	b	el0_inv
+	mov	x0, sp
+	bl	el0_sync_handler
+	b	ret_to_user
 
 #ifdef CONFIG_COMPAT
 	.align	6
 el0_sync_compat:
 	kernel_entry 0, 32
-	mrs	x25, esr_el1			// read the syndrome register
-	lsr	x24, x25, #ESR_ELx_EC_SHIFT	// exception class
-	cmp	x24, #ESR_ELx_EC_SVC32		// SVC in 32-bit state
-	b.eq	el0_svc_compat
-	cmp	x24, #ESR_ELx_EC_DABT_LOW	// data abort in EL0
-	b.eq	el0_da
-	cmp	x24, #ESR_ELx_EC_IABT_LOW	// instruction abort in EL0
-	b.eq	el0_ia
-	cmp	x24, #ESR_ELx_EC_FP_ASIMD	// FP/ASIMD access
-	b.eq	el0_fpsimd_acc
-	cmp	x24, #ESR_ELx_EC_FP_EXC32	// FP/ASIMD exception
-	b.eq	el0_fpsimd_exc
-	cmp	x24, #ESR_ELx_EC_PC_ALIGN	// pc alignment exception
-	b.eq	el0_pc
-	cmp	x24, #ESR_ELx_EC_UNKNOWN	// unknown exception in EL0
-	b.eq	el0_undef
-	cmp	x24, #ESR_ELx_EC_CP15_32	// CP15 MRC/MCR trap
-	b.eq	el0_cp15
-	cmp	x24, #ESR_ELx_EC_CP15_64	// CP15 MRRC/MCRR trap
-	b.eq	el0_cp15
-	cmp	x24, #ESR_ELx_EC_CP14_MR	// CP14 MRC/MCR trap
-	b.eq	el0_undef
-	cmp	x24, #ESR_ELx_EC_CP14_LS	// CP14 LDC/STC trap
-	b.eq	el0_undef
-	cmp	x24, #ESR_ELx_EC_CP14_64	// CP14 MRRC/MCRR trap
-	b.eq	el0_undef
-	cmp	x24, #ESR_ELx_EC_BREAKPT_LOW	// debug exception in EL0
-	b.ge	el0_dbg
-	b	el0_inv
-el0_svc_compat:
-	gic_prio_kentry_setup tmp=x1
 	mov	x0, sp
-	bl	el0_svc_compat_handler
+	bl	el0_sync_compat_handler
 	b	ret_to_user
+ENDPROC(el0_sync)
 
 	.align	6
 el0_irq_compat:
@@ -788,139 +668,7 @@ el0_irq_compat:
 el0_error_compat:
 	kernel_entry 0, 32
 	b	el0_error_naked
-
-el0_cp15:
-	/*
-	 * Trapped CP15 (MRC, MCR, MRRC, MCRR) instructions
-	 */
-	ct_user_exit_irqoff
-	enable_daif
-	mov	x0, x25
-	mov	x1, sp
-	bl	do_cp15instr
-	b	ret_to_user
-#endif
-
-el0_da:
-	/*
-	 * Data abort handling
-	 */
-	mrs	x26, far_el1
-	ct_user_exit_irqoff
-	enable_daif
-	untagged_addr	x0, x26
-	mov	x1, x25
-	mov	x2, sp
-	bl	do_mem_abort
-	b	ret_to_user
-el0_ia:
-	/*
-	 * Instruction abort handling
-	 */
-	mrs	x26, far_el1
-	gic_prio_kentry_setup tmp=x0
-	ct_user_exit_irqoff
-	enable_da_f
-#ifdef CONFIG_TRACE_IRQFLAGS
-	bl	trace_hardirqs_off
-#endif
-	mov	x0, x26
-	mov	x1, x25
-	mov	x2, sp
-	bl	do_el0_ia_bp_hardening
-	b	ret_to_user
-el0_fpsimd_acc:
-	/*
-	 * Floating Point or Advanced SIMD access
-	 */
-	ct_user_exit_irqoff
-	enable_daif
-	mov	x0, x25
-	mov	x1, sp
-	bl	do_fpsimd_acc
-	b	ret_to_user
-el0_sve_acc:
-	/*
-	 * Scalable Vector Extension access
-	 */
-	ct_user_exit_irqoff
-	enable_daif
-	mov	x0, x25
-	mov	x1, sp
-	bl	do_sve_acc
-	b	ret_to_user
-el0_fpsimd_exc:
-	/*
-	 * Floating Point, Advanced SIMD or SVE exception
-	 */
-	ct_user_exit_irqoff
-	enable_daif
-	mov	x0, x25
-	mov	x1, sp
-	bl	do_fpsimd_exc
-	b	ret_to_user
-el0_sp:
-	ldr	x26, [sp, #S_SP]
-	b	el0_sp_pc
-el0_pc:
-	mrs	x26, far_el1
-el0_sp_pc:
-	/*
-	 * Stack or PC alignment exception handling
-	 */
-	gic_prio_kentry_setup tmp=x0
-	ct_user_exit_irqoff
-	enable_da_f
-#ifdef CONFIG_TRACE_IRQFLAGS
-	bl	trace_hardirqs_off
 #endif
-	mov	x0, x26
-	mov	x1, x25
-	mov	x2, sp
-	bl	do_sp_pc_abort
-	b	ret_to_user
-el0_undef:
-	/*
-	 * Undefined instruction
-	 */
-	ct_user_exit_irqoff
-	enable_daif
-	mov	x0, sp
-	bl	do_undefinstr
-	b	ret_to_user
-el0_sys:
-	/*
-	 * System instructions, for trapped cache maintenance instructions
-	 */
-	ct_user_exit_irqoff
-	enable_daif
-	mov	x0, x25
-	mov	x1, sp
-	bl	do_sysinstr
-	b	ret_to_user
-el0_dbg:
-	/*
-	 * Debug exception handling
-	 */
-	tbnz	x24, #0, el0_inv		// EL0 only
-	mrs	x24, far_el1
-	gic_prio_kentry_setup tmp=x3
-	ct_user_exit_irqoff
-	mov	x0, x24
-	mov	x1, x25
-	mov	x2, sp
-	bl	do_debug_exception
-	enable_da_f
-	b	ret_to_user
-el0_inv:
-	ct_user_exit_irqoff
-	enable_daif
-	mov	x0, sp
-	mov	x1, #BAD_SYNC
-	mov	x2, x25
-	bl	bad_el0_sync
-	b	ret_to_user
-ENDPROC(el0_sync)
 
 	.align	6
 el0_irq:
@@ -999,17 +747,6 @@ finish_ret_to_user:
 	kernel_exit 0
 ENDPROC(ret_to_user)
 
-/*
- * SVC handler.
- */
-	.align	6
-el0_svc:
-	gic_prio_kentry_setup tmp=x1
-	mov	x0, sp
-	bl	el0_svc_handler
-	b	ret_to_user
-ENDPROC(el0_svc)
-
 	.popsection				// .entry.text
 
 #ifdef CONFIG_UNMAP_KERNEL_AT_EL0

arch/arm64/kernel/fpsimd.c

@@ -920,7 +920,7 @@ void fpsimd_release_task(struct task_struct *dead_task)
  * would have disabled the SVE access trap for userspace during
  * ret_to_user, making an SVE access trap impossible in that case.
  */
-asmlinkage void do_sve_acc(unsigned int esr, struct pt_regs *regs)
+void do_sve_acc(unsigned int esr, struct pt_regs *regs)
 {
 	/* Even if we chose not to use SVE, the hardware could still trap: */
 	if (unlikely(!system_supports_sve()) || WARN_ON(is_compat_task())) {
@@ -947,7 +947,7 @@ asmlinkage void do_sve_acc(unsigned int esr, struct pt_regs *regs)
 /*
  * Trapped FP/ASIMD access.
  */
-asmlinkage void do_fpsimd_acc(unsigned int esr, struct pt_regs *regs)
+void do_fpsimd_acc(unsigned int esr, struct pt_regs *regs)
 {
 	/* TODO: implement lazy context saving/restoring */
 	WARN_ON(1);
@@ -956,7 +956,7 @@ asmlinkage void do_fpsimd_acc(unsigned int esr, struct pt_regs *regs)
 /*
  * Raise a SIGFPE for the current process.
  */
-asmlinkage void do_fpsimd_exc(unsigned int esr, struct pt_regs *regs)
+void do_fpsimd_exc(unsigned int esr, struct pt_regs *regs)
 {
 	unsigned int si_code = FPE_FLTUNK;
 

arch/arm64/kernel/probes/kprobes.c

@@ -455,10 +455,6 @@ int __init arch_populate_kprobe_blacklist(void)
 					(unsigned long)__irqentry_text_end);
 	if (ret)
 		return ret;
-	ret = kprobe_add_area_blacklist((unsigned long)__exception_text_start,
-					(unsigned long)__exception_text_end);
-	if (ret)
-		return ret;
 	ret = kprobe_add_area_blacklist((unsigned long)__idmap_text_start,
 					(unsigned long)__idmap_text_end);
 	if (ret)

arch/arm64/kernel/syscall.c

@@ -154,14 +154,14 @@ static inline void sve_user_discard(void)
 	sve_user_disable();
 }
 
-asmlinkage void el0_svc_handler(struct pt_regs *regs)
+void el0_svc_handler(struct pt_regs *regs)
 {
 	sve_user_discard();
 	el0_svc_common(regs, regs->regs[8], __NR_syscalls, sys_call_table);
 }
 
 #ifdef CONFIG_COMPAT
-asmlinkage void el0_svc_compat_handler(struct pt_regs *regs)
+void el0_svc_compat_handler(struct pt_regs *regs)
 {
 	el0_svc_common(regs, regs->regs[7], __NR_compat_syscalls,
 		       compat_sys_call_table);

arch/arm64/kernel/traps.c

@@ -35,6 +35,7 @@
 #include <asm/debug-monitors.h>
 #include <asm/esr.h>
 #include <asm/insn.h>
+#include <asm/kprobes.h>
 #include <asm/traps.h>
 #include <asm/smp.h>
 #include <asm/stack_pointer.h>
@@ -393,7 +394,7 @@ void arm64_notify_segfault(unsigned long addr)
 	force_signal_inject(SIGSEGV, code, addr);
 }
 
-asmlinkage void __exception do_undefinstr(struct pt_regs *regs)
+void do_undefinstr(struct pt_regs *regs)
 {
 	/* check for AArch32 breakpoint instructions */
 	if (!aarch32_break_handler(regs))
@@ -405,6 +406,7 @@ asmlinkage void __exception do_undefinstr(struct pt_regs *regs)
 	BUG_ON(!user_mode(regs));
 	force_signal_inject(SIGILL, ILL_ILLOPC, regs->pc);
 }
+NOKPROBE_SYMBOL(do_undefinstr);
 
 #define __user_cache_maint(insn, address, res)			\
 	if (address >= user_addr_max()) {			\
@@ -676,7 +678,7 @@ static const struct sys64_hook cp15_64_hooks[] = {
 	{},
 };
 
-asmlinkage void __exception do_cp15instr(unsigned int esr, struct pt_regs *regs)
+void do_cp15instr(unsigned int esr, struct pt_regs *regs)
 {
 	const struct sys64_hook *hook, *hook_base;
 
@@ -714,9 +716,10 @@ asmlinkage void __exception do_cp15instr(unsigned int esr, struct pt_regs *regs)
 	 */
 	do_undefinstr(regs);
 }
+NOKPROBE_SYMBOL(do_cp15instr);
 #endif
 
-asmlinkage void __exception do_sysinstr(unsigned int esr, struct pt_regs *regs)
+void do_sysinstr(unsigned int esr, struct pt_regs *regs)
 {
 	const struct sys64_hook *hook;
 
@@ -733,6 +736,7 @@ asmlinkage void __exception do_sysinstr(unsigned int esr, struct pt_regs *regs)
 	 */
 	do_undefinstr(regs);
 }
+NOKPROBE_SYMBOL(do_sysinstr);
 
 static const char *esr_class_str[] = {
 	[0 ... ESR_ELx_EC_MAX]		= "UNRECOGNIZED EC",
@@ -802,7 +806,7 @@ asmlinkage void bad_mode(struct pt_regs *regs, int reason, unsigned int esr)
  * bad_el0_sync handles unexpected, but potentially recoverable synchronous
  * exceptions taken from EL0. Unlike bad_mode, this returns.
  */
-asmlinkage void bad_el0_sync(struct pt_regs *regs, int reason, unsigned int esr)
+void bad_el0_sync(struct pt_regs *regs, int reason, unsigned int esr)
 {
 	void __user *pc = (void __user *)instruction_pointer(regs);
 

arch/arm64/kernel/vmlinux.lds.S

@@ -111,9 +111,6 @@ SECTIONS
 	}
 	.text : {			/* Real text segment		*/
 		_stext = .;		/* Text and read-only data	*/
-			__exception_text_start = .;
-			*(.exception.text)
-			__exception_text_end = .;
 			IRQENTRY_TEXT
 			SOFTIRQENTRY_TEXT
 			ENTRY_TEXT

arch/arm64/mm/fault.c

@@ -32,7 +32,8 @@
 #include <asm/daifflags.h>
 #include <asm/debug-monitors.h>
 #include <asm/esr.h>
-#include <asm/kasan.h>
+#include <asm/kprobes.h>
+#include <asm/processor.h>
 #include <asm/sysreg.h>
 #include <asm/system_misc.h>
 #include <asm/pgtable.h>
@@ -101,18 +102,6 @@ static void mem_abort_decode(unsigned int esr)
 		data_abort_decode(esr);
 }
 
-static inline bool is_ttbr0_addr(unsigned long addr)
-{
-	/* entry assembly clears tags for TTBR0 addrs */
-	return addr < TASK_SIZE;
-}
-
-static inline bool is_ttbr1_addr(unsigned long addr)
-{
-	/* TTBR1 addresses may have a tag if KASAN_SW_TAGS is in use */
-	return arch_kasan_reset_tag(addr) >= PAGE_OFFSET;
-}
-
 static inline unsigned long mm_to_pgd_phys(struct mm_struct *mm)
 {
 	/* Either init_pg_dir or swapper_pg_dir */
@@ -736,8 +725,7 @@ static const struct fault_info fault_info[] = {
 	{ do_bad,		SIGKILL, SI_KERNEL,	"unknown 63"			},
 };
 
-asmlinkage void __exception do_mem_abort(unsigned long addr, unsigned int esr,
-					 struct pt_regs *regs)
+void do_mem_abort(unsigned long addr, unsigned int esr, struct pt_regs *regs)
 {
 	const struct fault_info *inf = esr_to_fault_info(esr);
 
@@ -753,43 +741,21 @@ asmlinkage void __exception do_mem_abort(unsigned long addr, unsigned int esr,
 	arm64_notify_die(inf->name, regs,
 			 inf->sig, inf->code, (void __user *)addr, esr);
 }
+NOKPROBE_SYMBOL(do_mem_abort);
 
-asmlinkage void __exception do_el0_irq_bp_hardening(void)
+void do_el0_irq_bp_hardening(void)
 {
 	/* PC has already been checked in entry.S */
 	arm64_apply_bp_hardening();
 }
+NOKPROBE_SYMBOL(do_el0_irq_bp_hardening);
 
-asmlinkage void __exception do_el0_ia_bp_hardening(unsigned long addr,
-						   unsigned int esr,
-						   struct pt_regs *regs)
-{
-	/*
-	 * We've taken an instruction abort from userspace and not yet
-	 * re-enabled IRQs. If the address is a kernel address, apply
-	 * BP hardening prior to enabling IRQs and pre-emption.
-	 */
-	if (!is_ttbr0_addr(addr))
-		arm64_apply_bp_hardening();
-
-	local_daif_restore(DAIF_PROCCTX);
-	do_mem_abort(addr, esr, regs);
-}
-
-
-asmlinkage void __exception do_sp_pc_abort(unsigned long addr,
-					   unsigned int esr,
-					   struct pt_regs *regs)
+void do_sp_pc_abort(unsigned long addr, unsigned int esr, struct pt_regs *regs)
 {
-	if (user_mode(regs)) {
-		if (!is_ttbr0_addr(instruction_pointer(regs)))
-			arm64_apply_bp_hardening();
-		local_daif_restore(DAIF_PROCCTX);
-	}
-
 	arm64_notify_die("SP/PC alignment exception", regs,
 			 SIGBUS, BUS_ADRALN, (void __user *)addr, esr);
 }
+NOKPROBE_SYMBOL(do_sp_pc_abort);
 
 int __init early_brk64(unsigned long addr, unsigned int esr,
 		       struct pt_regs *regs);
@@ -872,8 +838,7 @@ NOKPROBE_SYMBOL(debug_exception_exit);
 #ifdef CONFIG_ARM64_ERRATUM_1463225
 DECLARE_PER_CPU(int, __in_cortex_a76_erratum_1463225_wa);
 
-static int __exception
-cortex_a76_erratum_1463225_debug_handler(struct pt_regs *regs)
+static int cortex_a76_erratum_1463225_debug_handler(struct pt_regs *regs)
 {
 	if (user_mode(regs))
 		return 0;
@@ -892,15 +857,14 @@ cortex_a76_erratum_1463225_debug_handler(struct pt_regs *regs)
 	return 1;
 }
 #else
-static int __exception
-cortex_a76_erratum_1463225_debug_handler(struct pt_regs *regs)
+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);
 
-asmlinkage void __exception do_debug_exception(unsigned long addr_if_watchpoint,
-					       unsigned int esr,
+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);