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Commit 2129cf58 authored by Mike Frysinger's avatar Mike Frysinger Committed by Sasha Levin
Browse files

sparc: Fix system call tracing register handling. 



[ Upstream commit 1a40b95374f680625318ab61d81958e949e0afe3 ]

A system call trace trigger on entry allows the tracing
process to inspect and potentially change the traced
process's registers.

Account for that by reloading the %g1 (syscall number)
and %i0-%i5 (syscall argument) values.  We need to be
careful to revalidate the range of %g1, and reload the
system call table entry it corresponds to into %l7.

Reported-by: default avatarMike Frysinger <vapier@gentoo.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
Tested-by: default avatarMike Frysinger <vapier@gentoo.org>
Signed-off-by: default avatarSasha Levin <sasha.levin@oracle.com>
parent 25b37ef7

arch/sparc/kernel/entry.S

+17 −0
Original line number Diff line number Diff line
@@ -948,7 +948,24 @@ linux_syscall_trace: 
	cmp	%o0, 0

	bne	3f

	 mov	-ENOSYS, %o0



	/* Syscall tracing can modify the registers.  */

	ld	[%sp + STACKFRAME_SZ + PT_G1], %g1

	sethi	%hi(sys_call_table), %l7

	ld	[%sp + STACKFRAME_SZ + PT_I0], %i0

	or	%l7, %lo(sys_call_table), %l7

	ld	[%sp + STACKFRAME_SZ + PT_I1], %i1

	ld	[%sp + STACKFRAME_SZ + PT_I2], %i2

	ld	[%sp + STACKFRAME_SZ + PT_I3], %i3

	ld	[%sp + STACKFRAME_SZ + PT_I4], %i4

	ld	[%sp + STACKFRAME_SZ + PT_I5], %i5

	cmp	%g1, NR_syscalls

	bgeu	3f

	 mov	-ENOSYS, %o0



	sll	%g1, 2, %l4

	mov	%i0, %o0

	ld	[%l7 + %l4], %l7

	mov	%i1, %o1

	mov	%i2, %o2

	mov	%i3, %o3

arch/sparc/kernel/syscalls.S

+36 −0
Original line number Diff line number Diff line
@@ -148,7 +148,25 @@ linux_syscall_trace32: 
	 add	%sp, PTREGS_OFF, %o0

	brnz,pn	%o0, 3f

	 mov	-ENOSYS, %o0



	/* Syscall tracing can modify the registers.  */

	ldx	[%sp + PTREGS_OFF + PT_V9_G1], %g1

	sethi	%hi(sys_call_table32), %l7

	ldx	[%sp + PTREGS_OFF + PT_V9_I0], %i0

	or	%l7, %lo(sys_call_table32), %l7

	ldx	[%sp + PTREGS_OFF + PT_V9_I1], %i1

	ldx	[%sp + PTREGS_OFF + PT_V9_I2], %i2

	ldx	[%sp + PTREGS_OFF + PT_V9_I3], %i3

	ldx	[%sp + PTREGS_OFF + PT_V9_I4], %i4

	ldx	[%sp + PTREGS_OFF + PT_V9_I5], %i5



	cmp	%g1, NR_syscalls

	bgeu,pn	%xcc, 3f

	 mov	-ENOSYS, %o0



	sll	%g1, 2, %l4

	srl	%i0, 0, %o0

	lduw	[%l7 + %l4], %l7

	srl	%i4, 0, %o4

	srl	%i1, 0, %o1

	srl	%i2, 0, %o2
@@ -160,7 +178,25 @@ linux_syscall_trace: 
	 add	%sp, PTREGS_OFF, %o0

	brnz,pn	%o0, 3f

	 mov	-ENOSYS, %o0



	/* Syscall tracing can modify the registers.  */

	ldx	[%sp + PTREGS_OFF + PT_V9_G1], %g1

	sethi	%hi(sys_call_table64), %l7

	ldx	[%sp + PTREGS_OFF + PT_V9_I0], %i0

	or	%l7, %lo(sys_call_table64), %l7

	ldx	[%sp + PTREGS_OFF + PT_V9_I1], %i1

	ldx	[%sp + PTREGS_OFF + PT_V9_I2], %i2

	ldx	[%sp + PTREGS_OFF + PT_V9_I3], %i3

	ldx	[%sp + PTREGS_OFF + PT_V9_I4], %i4

	ldx	[%sp + PTREGS_OFF + PT_V9_I5], %i5



	cmp	%g1, NR_syscalls

	bgeu,pn	%xcc, 3f

	 mov	-ENOSYS, %o0



	sll	%g1, 2, %l4

	mov	%i0, %o0

	lduw	[%l7 + %l4], %l7

	mov	%i1, %o1

	mov	%i2, %o2

	mov	%i3, %o3