Thread (20 messages) 20 messages, 4 authors, 2016-04-20

[PATCH V2 5/9] arm64: exception: handle instruction abort at current EL

From: Marc Zyngier <hidden>
Date: 2016-04-06 15:36:53
Also in: linux-acpi, linux-efi, lkml

On 06/04/16 16:12, Tyler Baicar wrote:
quoted hunk ↗ jump to hunk
Add a handler for instruction aborts at the current EL
(ESR_ELx_EC_IABT_CUR) so they are no longer handled in el1_inv.
This allows firmware first handling for possible SEA
(Synchronous External Abort) caused instruction abort at
current EL.

Signed-off-by: Tyler Baicar <redacted>
Signed-off-by: Naveen Kaje <redacted>
---
 arch/arm64/kernel/entry.S | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)
diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S
index 12e8d2b..f257856 100644
--- a/arch/arm64/kernel/entry.S
+++ b/arch/arm64/kernel/entry.S
@@ -336,6 +336,8 @@ el1_sync:
 	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_SP_ALIGN	// stack alignment exception
@@ -363,6 +365,23 @@ el1_da:
 	// disable interrupts before pulling preserved data off the stack
 	disable_irq
 	kernel_exit 1
+el1_ia:
+	/*
+	 * Instruction abort handling
+	 */
+	mrs	x0, far_el1
+	enable_dbg
+	// re-enable interrupts if they were enabled in the aborted context
+	tbnz	x23, #7, 1f			// PSR_I_BIT
+	enable_irq
+1:
+	orr	x1, x1, #1 << 24		// use reserved ISS bit for instruction aborts
+	mov	x2, sp				// struct pt_regs
+	bl	do_mem_abort
+
+	// disable interrupts before pulling preserved data off the stack
+	disable_irq
+	kernel_exit 1
 el1_sp_pc:
 	/*
 	 * Stack or PC alignment exception handling
What happens if you were running at EL2 when this faults gets injected?
It looks like KVM needs something similar, doesn't it?

Thanks,

	M.
-- 
Jazz is not dead. It just smells funny...
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