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ARM: 7839/1: entry: fix tracing of ARM-private syscalls

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Commit 377747c406 ("ARM: entry: allow ARM-private syscalls to be
restarted") reworked the low-level syscall dispatcher to allow
restarting of ARM-private syscalls. Unfortunately, this relocated the
label used to dispatch a private syscall from the trace path, so that
the invocation would be bypassed altogether!

This causes applications to fail under strace as soon as they rely on
a private syscall (e.g. set_tls):

  set_tls(0xb6fad4c0, 0xb6fadb98, 0xb6fb1050, 0xb6fad4c0, 0xb6fb1050)
      = -1 ENOSYS (Function not implemented)

This patch fixes the label so that we correctly dispatch private
syscalls from the trace path.

Reported-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
Tested-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This commit is contained in:
Will Deacon 2013-09-19 10:32:20 +01:00 committed by Russell King
parent c89efa731e
commit d95bc2501d
1 changed files with 2 additions and 2 deletions
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4
arch/arm/kernel/entry-common.S
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@ -442,10 +442,10 @@ local_restart:
ldrcc pc, [tbl, scno, lsl #2] @ call sys_* routine
add r1, sp, #S_OFF
cmp scno, #(__ARM_NR_BASE - __NR_SYSCALL_BASE)
2: cmp scno, #(__ARM_NR_BASE - __NR_SYSCALL_BASE)
eor r0, scno, #__NR_SYSCALL_BASE @ put OS number back
bcs arm_syscall
2: mov why, #0 @ no longer a real syscall
mov why, #0 @ no longer a real syscall
b sys_ni_syscall @ not private func
#if defined(CONFIG_OABI_COMPAT) || !defined(CONFIG_AEABI)