Commit 1b42804d authored Jul 07, 2015 by Mark Rutland Committed by Catalin Marinas Jul 08, 2015

arm64: entry: handle debug exceptions in el*_inv



Currently we enable debug exceptions before reading ESR_EL1 in both
el0_inv and el1_inv. If a debug exception is taken before we read
ESR_EL1, the value will have been corrupted.

As el*_inv is typically fatal, an intervening debug exception results in
misleading debug information being logged to the console, but is not
otherwise harmful.

As with the other entry paths, we can use the ESR_EL1 value stashed
earlier in the exception entry (in x25 for el0_sync{,_compat}, and x1
for el1_sync), giving us better error reporting in this case.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

parent ef37566c

arch/arm64/kernel/entry.S

+2 −2

Original line number	Diff line number	Diff line
		@@ -352,8 +352,8 @@ el1_inv:
		// TODO: add support for undefined instructions in kernel mode
		enable_dbg
		mov x0, sp
		mov x2, x1
		mov x1, #BAD_SYNC
		mrs x2, esr_el1
		b bad_mode
		ENDPROC(el1_sync)

		@@ -553,7 +553,7 @@ el0_inv:
		ct_user_exit
		mov x0, sp
		mov x1, #BAD_SYNC
		mrs x2, esr_el1
		mov x2, x25
		bl bad_mode
		b ret_to_user
		ENDPROC(el0_sync)