[PATCH 07/17] arm64: entry: convert error entry to C

Mark Rutland mark.rutland at arm.com
Wed Jan 8 10:56:24 PST 2020


Portions of our error entry logic are handled in C while other parts are
handled in assembly. Let's migrate the bulk of it to C so that it's
easier to follow and maintain.

Signed-off-by: Mark Rutland <mark.rutland at arm.com>
Cc: Catalin Marinas <catalin.marinas at arm.com>
Cc: James Morse <james.morse at arm.com>
Cc: Will Deacon <will at kernel.org>
---
 arch/arm64/include/asm/exception.h |  1 +
 arch/arm64/kernel/entry-common.c   | 26 ++++++++++++++++++++++++++
 arch/arm64/kernel/entry.S          | 19 ++++++-------------
 arch/arm64/kernel/traps.c          |  2 +-
 4 files changed, 34 insertions(+), 14 deletions(-)

diff --git a/arch/arm64/include/asm/exception.h b/arch/arm64/include/asm/exception.h
index a49038fa4faf..220a7c3971d8 100644
--- a/arch/arm64/include/asm/exception.h
+++ b/arch/arm64/include/asm/exception.h
@@ -51,5 +51,6 @@ void do_el0_svc(struct pt_regs *regs);
 void do_el0_svc_compat(struct pt_regs *regs);
 void do_el0_ia_bp_hardening(unsigned long addr,  unsigned int esr,
 			    struct pt_regs *regs);
+void do_serror(struct pt_regs *regs, unsigned int esr);
 
 #endif	/* __ASM_EXCEPTION_H */
diff --git a/arch/arm64/kernel/entry-common.c b/arch/arm64/kernel/entry-common.c
index 45155d9f72da..bf9d497e620c 100644
--- a/arch/arm64/kernel/entry-common.c
+++ b/arch/arm64/kernel/entry-common.c
@@ -442,3 +442,29 @@ asmlinkage void notrace el0_irq_handler(struct pt_regs *regs)
 	trace_hardirqs_on();
 }
 NOKPROBE_SYMBOL(el0_irq_handler);
+
+asmlinkage void el1_error_handler(struct pt_regs *regs)
+{
+	unsigned long esr = read_sysreg(esr_el1);
+
+	if (system_uses_irq_prio_masking())
+		gic_write_pmr(GIC_PRIO_IRQON | GIC_PRIO_PSR_I_SET);
+
+	local_daif_restore(DAIF_ERRCTX);
+	do_serror(regs, esr);
+}
+NOKPROBE_SYMBOL(el1_error_handler);
+
+asmlinkage void el0_error_handler(struct pt_regs *regs)
+{
+	unsigned long esr = read_sysreg(esr_el1);
+
+	if (system_uses_irq_prio_masking())
+		gic_write_pmr(GIC_PRIO_IRQON | GIC_PRIO_PSR_I_SET);
+
+	user_exit_irqoff();
+	local_daif_restore(DAIF_ERRCTX);
+	do_serror(regs, esr);
+	local_daif_restore(DAIF_PROCCTX_NOIRQ);
+}
+NOKPROBE_SYMBOL(el0_error_handler);
diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S
index 55c4be1e996a..0c5117ef7c3c 100644
--- a/arch/arm64/kernel/entry.S
+++ b/arch/arm64/kernel/entry.S
@@ -559,7 +559,10 @@ ENDPROC(el0_irq_compat)
 
 el0_error_compat:
 	kernel_entry 0, 32
-	b	el0_error_naked
+	mov	x0, sp
+	bl	el0_error_handler
+	b	ret_to_user
+ENDPROC(el0_error_compat)
 #endif
 
 	.align	6
@@ -572,25 +575,15 @@ ENDPROC(el0_irq)
 
 el1_error:
 	kernel_entry 1
-	mrs	x1, esr_el1
-	gic_prio_kentry_setup tmp=x2
-	enable_dbg
 	mov	x0, sp
-	bl	do_serror
+	bl	el1_error_handler
 	kernel_exit 1
 ENDPROC(el1_error)
 
 el0_error:
 	kernel_entry 0
-el0_error_naked:
-	mrs	x25, esr_el1
-	gic_prio_kentry_setup tmp=x2
-	ct_user_exit_irqoff
-	enable_dbg
 	mov	x0, sp
-	mov	x1, x25
-	bl	do_serror
-	enable_da_f
+	bl	el0_error_handler
 	b	ret_to_user
 ENDPROC(el0_error)
 
diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c
index 73caf35c2262..170e637bb87b 100644
--- a/arch/arm64/kernel/traps.c
+++ b/arch/arm64/kernel/traps.c
@@ -901,7 +901,7 @@ bool arm64_is_fatal_ras_serror(struct pt_regs *regs, unsigned int esr)
 	}
 }
 
-asmlinkage void do_serror(struct pt_regs *regs, unsigned int esr)
+void do_serror(struct pt_regs *regs, unsigned int esr)
 {
 	const bool was_in_nmi = in_nmi();
 
-- 
2.11.0




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