Commit c7aa00db authored Jul 19, 2012 by Will Deacon Committed by Russell King Jul 28, 2012

ARM: 7475/1: sys_trace: allow all syscall arguments to be updated via ptrace



Prior to syscall invocation, __sys_trace only reloads r0-r3 from the
kernel stack, preventing the debugger from updating arguments 5-7 when
signalled via ptrace.

This patch updates the code to reload r0-r6, updating arguments 5 and 6
on the stack (argument 7 is only used by OABI indirect syscalls and
can remain in a register).

Reported-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

parent 66285217

arch/arm/kernel/entry-common.S

+2 −1

Original line number	Diff line number	Diff line
		@@ -443,7 +443,8 @@ __sys_trace:
		mov scno, r0 @ syscall number (possibly new)
		add r1, sp, #S_R0 + S_OFF @ pointer to regs
		cmp scno, #NR_syscalls @ check upper syscall limit
		ldmccia r1, {r0 - r3} @ have to reload r0 - r3
		ldmccia r1, {r0 - r6} @ have to reload r0 - r6
		stmccia sp, {r4, r5} @ and update the stack args
		ldrcc pc, [tbl, scno, lsl #2] @ call sys_* routine
		b 2b