arm64: entry: convert el1_sync to C

This patch converts the EL1 sync entry assembly logic to C code.

Doing this will allow us to make changes in a slightly more
readable way. A case in point is supporting kernel-first RAS.
do_sea() should be called on the CPU that took the fault.

Largely the assembly code is converted to C in a relatively
straightforward manner.

Since all sync sites share a common asm entry point, the ASM_BUG()
instances are no longer required for effective backtraces back to
assembly, and we don't need similar BUG() entries.

The ESR_ELx.EC codes for all (supported) debug exceptions are now
checked in the el1_sync_handler's switch statement, which renders the
check in el1_dbg redundant. This both simplifies the el1_dbg handler,
and makes the EL1 exception handling more robust to
currently-unallocated ESR_ELx.EC encodings.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
[split out of a bigger series, added nokprobes, moved prototypes]
Signed-off-by: James Morse <james.morse@arm.com>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Cc: Julien Thierry <julien.thierry.kdev@gmail.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

1 files changed, 1 insertions, 68 deletions

diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S
index e304fe04b098..5d7f42eb0e89 100644
--- a/arch/arm64/kernel/entry.S
+++ b/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
-	clear_address_tag 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
-	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
+	bl	el1_sync_handler
 	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