arm64: consistently pass ESR_ELx to die()

Currently, bug_handler() and kasan_handler() call die() with '0' as the
'err' value, whereas die_kernel_fault() passes the ESR_ELx value.

For consistency, this patch ensures we always pass the ESR_ELx value to
die(). As this is only called for exceptions taken from kernel mode,
there should be no user-visible change as a result of this patch.

For UNDEFINED exceptions, I've had to modify do_undefinstr() and its
callers to pass the ESR_ELx value. In all cases the ESR_ELx value had
already been read and was available.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Mark Brown <broonie@kernel.org>
Cc: Alexandru Elisei <alexandru.elisei@arm.com>
Cc: Amit Daniel Kachhap <amit.kachhap@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: Will Deacon <will@kernel.org>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Reviewed-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20220913101732.3925290-4-mark.rutland@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

Author: mrutland-arm

arch/arm64/include/asm/exception.h

@@ -58,7 +58,7 @@ asmlinkage void call_on_irq_stack(struct pt_regs *regs,
 asmlinkage void asm_exit_to_user_mode(struct pt_regs *regs);
 
 void do_mem_abort(unsigned long far, unsigned long esr, struct pt_regs *regs);
-void do_undefinstr(struct pt_regs *regs);
+void do_undefinstr(struct pt_regs *regs, unsigned long esr);
 void do_bti(struct pt_regs *regs);
 void do_debug_exception(unsigned long addr_if_watchpoint, unsigned long esr,
 			struct pt_regs *regs);

arch/arm64/kernel/entry-common.c

@@ -379,11 +379,11 @@ static void noinstr el1_pc(struct pt_regs *regs, unsigned long esr)
 	exit_to_kernel_mode(regs);
 }
 
-static void noinstr el1_undef(struct pt_regs *regs)
+static void noinstr el1_undef(struct pt_regs *regs, unsigned long esr)
 {
 	enter_from_kernel_mode(regs);
 	local_daif_inherit(regs);
-	do_undefinstr(regs);
+	do_undefinstr(regs, esr);
 	local_daif_mask();
 	exit_to_kernel_mode(regs);
 }
@@ -425,7 +425,7 @@ asmlinkage void noinstr el1h_64_sync_handler(struct pt_regs *regs)
 		break;
 	case ESR_ELx_EC_SYS64:
 	case ESR_ELx_EC_UNKNOWN:
-		el1_undef(regs);
+		el1_undef(regs, esr);
 		break;
 	case ESR_ELx_EC_BREAKPT_CUR:
 	case ESR_ELx_EC_SOFTSTP_CUR:
@@ -582,11 +582,11 @@ static void noinstr el0_sp(struct pt_regs *regs, unsigned long esr)
 	exit_to_user_mode(regs);
 }
 
-static void noinstr el0_undef(struct pt_regs *regs)
+static void noinstr el0_undef(struct pt_regs *regs, unsigned long esr)
 {
 	enter_from_user_mode(regs);
 	local_daif_restore(DAIF_PROCCTX);
-	do_undefinstr(regs);
+	do_undefinstr(regs, esr);
 	exit_to_user_mode(regs);
 }
 
@@ -670,7 +670,7 @@ asmlinkage void noinstr el0t_64_sync_handler(struct pt_regs *regs)
 		el0_pc(regs, esr);
 		break;
 	case ESR_ELx_EC_UNKNOWN:
-		el0_undef(regs);
+		el0_undef(regs, esr);
 		break;
 	case ESR_ELx_EC_BTI:
 		el0_bti(regs);
@@ -788,7 +788,7 @@ asmlinkage void noinstr el0t_32_sync_handler(struct pt_regs *regs)
 	case ESR_ELx_EC_CP14_MR:
 	case ESR_ELx_EC_CP14_LS:
 	case ESR_ELx_EC_CP14_64:
-		el0_undef(regs);
+		el0_undef(regs, esr);
 		break;
 	case ESR_ELx_EC_CP15_32:
 	case ESR_ELx_EC_CP15_64:

arch/arm64/kernel/traps.c

@@ -485,7 +485,7 @@ void arm64_notify_segfault(unsigned long addr)
 	force_signal_inject(SIGSEGV, code, addr, 0);
 }
 
-void do_undefinstr(struct pt_regs *regs)
+void do_undefinstr(struct pt_regs *regs, unsigned long esr)
 {
 	/* check for AArch32 breakpoint instructions */
 	if (!aarch32_break_handler(regs))
@@ -495,7 +495,7 @@ void do_undefinstr(struct pt_regs *regs)
 		return;
 
 	if (!user_mode(regs))
-		die("Oops - Undefined instruction", regs, 0);
+		die("Oops - Undefined instruction", regs, esr);
 
 	force_signal_inject(SIGILL, ILL_ILLOPC, regs->pc, 0);
 }
@@ -760,7 +760,7 @@ void do_cp15instr(unsigned long esr, struct pt_regs *regs)
 		hook_base = cp15_64_hooks;
 		break;
 	default:
-		do_undefinstr(regs);
+		do_undefinstr(regs, esr);
 		return;
 	}
 
@@ -775,7 +775,7 @@ void do_cp15instr(unsigned long esr, struct pt_regs *regs)
 	 * EL0. Fall back to our usual undefined instruction handler
 	 * so that we handle these consistently.
 	 */
-	do_undefinstr(regs);
+	do_undefinstr(regs, esr);
 }
 NOKPROBE_SYMBOL(do_cp15instr);
 #endif
@@ -795,7 +795,7 @@ void do_sysinstr(unsigned long esr, struct pt_regs *regs)
 	 * back to our usual undefined instruction handler so that we handle
 	 * these consistently.
 	 */
-	do_undefinstr(regs);
+	do_undefinstr(regs, esr);
 }
 NOKPROBE_SYMBOL(do_sysinstr);
 
@@ -972,7 +972,7 @@ static int bug_handler(struct pt_regs *regs, unsigned long esr)
 {
 	switch (report_bug(regs->pc, regs)) {
 	case BUG_TRAP_TYPE_BUG:
-		die("Oops - BUG", regs, 0);
+		die("Oops - BUG", regs, esr);
 		break;
 
 	case BUG_TRAP_TYPE_WARN:
@@ -1040,7 +1040,7 @@ static int kasan_handler(struct pt_regs *regs, unsigned long esr)
 	 * This is something that might be fixed at some point in the future.
 	 */
 	if (!recover)
-		die("Oops - KASAN", regs, 0);
+		die("Oops - KASAN", regs, esr);
 
 	/* If thread survives, skip over the brk instruction and continue: */
 	arm64_skip_faulting_instruction(regs, AARCH64_INSN_SIZE);