[PATCH v2 08/16] arm64: entry.S: move SError handling into a C function for future expansion

[James Morse]

From: Xie XiuQi <xiexiuqi at huawei.com>

Today SError is taken using the inv_entry macro that ends up in
bad_mode.

SError can be used by the RAS Extensions to notify either the OS or
firmware of CPU problems, some of which may have been corrected.

To allow this handling to be added, add a do_serror() C function
that just panic()s. Add the entry.S boiler plate to save/restore the
CPU registers. Future patches may change do_serror() to return if the
SError Interrupt was notification of a corrected error.

Use nmi_panic() so that an SError taken during a regular panic()
continues to process the first panic().

Signed-off-by: Xie XiuQi <xiexiuqi at huawei.com>
Signed-off-by: Wang Xiongfeng <wangxiongfengi2 at huawei.com>
[Split out of a bigger patch, added compat path, renamed, enabled debug
 exceptions]
Signed-off-by: James Morse <james.morse at arm.com>
---
 arch/arm64/Kconfig        |  2 +-
 arch/arm64/kernel/entry.S | 34 +++++++++++++++++++++++++++-------
 arch/arm64/kernel/traps.c | 15 +++++++++++++++
 3 files changed, 43 insertions(+), 8 deletions(-)

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index dfd908630631..d3913cffa3ac 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -97,7 +97,7 @@ config ARM64
 	select HAVE_IRQ_TIME_ACCOUNTING
 	select HAVE_MEMBLOCK
 	select HAVE_MEMBLOCK_NODE_MAP if NUMA
-	select HAVE_NMI if ACPI_APEI_SEA
+	select HAVE_NMI
 	select HAVE_PATA_PLATFORM
 	select HAVE_PERF_EVENTS
 	select HAVE_PERF_REGS
diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S
index 2fde60f96239..9e63f69e1366 100644
--- a/arch/arm64/kernel/entry.S
+++ b/arch/arm64/kernel/entry.S
@@ -329,18 +329,18 @@ ENTRY(vectors)
 	ventry	el1_sync			// Synchronous EL1h
 	ventry	el1_irq				// IRQ EL1h
 	ventry	el1_fiq_invalid			// FIQ EL1h
-	ventry	el1_error_invalid		// Error EL1h
+	ventry	el1_serror			// Error EL1h
 
 	ventry	el0_sync			// Synchronous 64-bit EL0
 	ventry	el0_irq				// IRQ 64-bit EL0
 	ventry	el0_fiq_invalid			// FIQ 64-bit EL0
-	ventry	el0_error_invalid		// Error 64-bit EL0
+	ventry	el0_serror			// Error 64-bit EL0
 
 #ifdef CONFIG_COMPAT
 	ventry	el0_sync_compat			// Synchronous 32-bit EL0
 	ventry	el0_irq_compat			// IRQ 32-bit EL0
 	ventry	el0_fiq_invalid_compat		// FIQ 32-bit EL0
-	ventry	el0_error_invalid_compat	// Error 32-bit EL0
+	ventry	el0_serror_compat		// Error 32-bit EL0
 #else
 	ventry	el0_sync_invalid		// Synchronous 32-bit EL0
 	ventry	el0_irq_invalid			// IRQ 32-bit EL0
@@ -380,10 +380,6 @@ ENDPROC(el0_error_invalid)
 el0_fiq_invalid_compat:
 	inv_entry 0, BAD_FIQ, 32
 ENDPROC(el0_fiq_invalid_compat)
-
-el0_error_invalid_compat:
-	inv_entry 0, BAD_ERROR, 32
-ENDPROC(el0_error_invalid_compat)
 #endif
 
 el1_sync_invalid:
@@ -593,6 +589,10 @@ el0_svc_compat:
 el0_irq_compat:
 	kernel_entry 0, 32
 	b	el0_irq_naked
+
+el0_serror_compat:
+	kernel_entry 0, 32
+	b	el0_serror_naked
 #endif
 
 el0_da:
@@ -691,6 +691,26 @@ el0_irq_naked:
 	b	ret_to_user
 ENDPROC(el0_irq)
 
+el1_serror:
+	kernel_entry 1
+	mrs	x1, esr_el1
+	mov	x0, sp
+	bl	do_serror
+	kernel_exit 1
+ENDPROC(el1_serror)
+
+el0_serror:
+	kernel_entry 0
+el0_serror_naked:
+	mrs	x1, esr_el1
+	mov	x0, sp
+	bl	do_serror
+	enable_daif
+	ct_user_exit
+	b	ret_to_user
+ENDPROC(el0_serror)
+
+
 /*
  * Register switch for AArch64. The callee-saved registers need to be saved
  * and restored. On entry:
diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c
index 59efec10be15..943a0e242dbc 100644
--- a/arch/arm64/kernel/traps.c
+++ b/arch/arm64/kernel/traps.c
@@ -685,6 +685,21 @@ asmlinkage void bad_el0_sync(struct pt_regs *regs, int reason, unsigned int esr)
 	force_sig_info(info.si_signo, &info, current);
 }
 
+asmlinkage void do_serror(struct pt_regs *regs, unsigned int esr)
+{
+	nmi_enter();
+
+	console_verbose();
+
+	pr_crit("SError Interrupt on CPU%d, code 0x%08x -- %s\n",
+		smp_processor_id(), esr, esr_get_class_string(esr));
+	__show_regs(regs);
+
+	nmi_panic(regs, "Asynchronous SError Interrupt");
+
+	nmi_exit();
+}
+
 void __pte_error(const char *file, int line, unsigned long val)
 {
 	pr_err("%s:%d: bad pte %016lx.\n", file, line, val);
-- 
2.13.2