[ARM] 3335/1: Old-abi Thumb sys_syscall broken

Patch from Paul Brook

The old-abi sys_syscall syscall is broken when called from Thumb mode. It
assumes the syscall number is an Arm syscall number (ie. starts from
__NR_OABI_SYSCALL_BASE).  In thumb mode syscall numbers start from zero.

The patch below fixes this by clearing the nigh bits of the syscall number
instead of inverting them. Technically this means we accept some invalid
syscall numbers, but I can't see how that could be a problem. The two sets of
numbers far apart that unimplemented syscalls should still be rejected.

Signed-off-by: Paul Brook <paul@codesourcery.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

diff --git a/arch/arm/kernel/entry-common.S b/arch/arm/kernel/entry-common.S
index dbcb11a31f78167b5577c55cfe4660c922043a20..b5bcebca1cd65ed9abaecf520a97eea535752564 100644 (file)
--- a/arch/arm/kernel/entry-common.S
+++ b/arch/arm/kernel/entry-common.S
@@ -271,7 +271,7 @@ ENTRY(sys_call_table)
 @ r8 = syscall table
                .type   sys_syscall, #function
 sys_syscall:
-               eor     scno, r0, #__NR_OABI_SYSCALL_BASE
+               bic     scno, r0, #__NR_OABI_SYSCALL_BASE
                cmp     scno, #__NR_syscall - __NR_SYSCALL_BASE
                cmpne   scno, #NR_syscalls      @ check range
                stmloia sp, {r5, r6}            @ shuffle args