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sparc: Fix system call tracing register handling.

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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: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Tested-by: Mike Frysinger <vapier@gentoo.org>
This commit is contained in:
Mike Frysinger 2016-01-18 06:32:30 -05:00 committed by David S. Miller
parent c10910c323
commit 1a40b95374
2 changed files with 53 additions and 0 deletions
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17
arch/sparc/kernel/entry.S
View File

@ -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

36
arch/sparc/kernel/syscalls.S
View File

@ -158,7 +158,25 @@ 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
@ -170,7 +188,25 @@ 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