On Fri, Aug 05, 2011 at 10:27:21AM +0100, Peter Maydell wrote: > On 5 August 2011 01:05, An-Cheng Huang <anch...@ubnt.com> wrote: > > Ok the following patch changes the number of arguments for sys_syscall > > to 8 in mips_syscall_args and also skips the do_syscall() call if any > > of the get_user() calls fails. Do you think combining these makes sense > > or should they be two separate patches? Thanks. > > The code in this patch looks good, but yes, I think they should > be two separate patches.
And the second patch: This patch verifies that MIPS syscall arguments are successfully taken from the stack before proceeding to do_syscall(). Signed-off-by: An-Cheng Huang <anch...@ubnt.com> --- linux-user/main.c | 22 +++++++++++++++++----- 1 files changed, 17 insertions(+), 5 deletions(-) diff --git a/linux-user/main.c b/linux-user/main.c index 9e67b24..701d96e 100644 --- a/linux-user/main.c +++ b/linux-user/main.c @@ -2090,11 +2090,22 @@ void cpu_loop(CPUMIPSState *env) sp_reg = env->active_tc.gpr[29]; switch (nb_args) { /* these arguments are taken from the stack */ - /* FIXME - what to do if get_user() fails? */ - case 8: get_user_ual(arg8, sp_reg + 28); - case 7: get_user_ual(arg7, sp_reg + 24); - case 6: get_user_ual(arg6, sp_reg + 20); - case 5: get_user_ual(arg5, sp_reg + 16); + case 8: + if ((ret = get_user_ual(arg8, sp_reg + 28)) != 0) { + goto done_syscall; + } + case 7: + if ((ret = get_user_ual(arg7, sp_reg + 24)) != 0) { + goto done_syscall; + } + case 6: + if ((ret = get_user_ual(arg6, sp_reg + 20)) != 0) { + goto done_syscall; + } + case 5: + if ((ret = get_user_ual(arg5, sp_reg + 16)) != 0) { + goto done_syscall; + } default: break; } @@ -2105,6 +2116,7 @@ void cpu_loop(CPUMIPSState *env) env->active_tc.gpr[7], arg5, arg6, arg7, arg8); } +done_syscall: if (ret == -TARGET_QEMU_ESIGRETURN) { /* Returning from a successful sigreturn syscall. Avoid clobbering register state. */