From 1d80f0cda10118d7505bd0a09a5c1c72f3a5f6c8 Mon Sep 17 00:00:00 2001 From: Richard Weinberger Date: Sun, 25 Oct 2015 19:54:33 +0100 Subject: [PATCH] um: Store syscall number after syscall_trace_enter() To support changing syscall numbers we have to store it after syscall_trace_enter(). Signed-off-by: Richard Weinberger --- arch/um/include/shared/os.h | 1 + arch/um/kernel/skas/syscall.c | 13 +++---------- arch/um/os-Linux/skas/process.c | 10 +++++++--- 3 files changed, 11 insertions(+), 13 deletions(-) diff --git a/arch/um/include/shared/os.h b/arch/um/include/shared/os.h index ad3fa3ae6d34..f3cbaef20e04 100644 --- a/arch/um/include/shared/os.h +++ b/arch/um/include/shared/os.h @@ -274,6 +274,7 @@ extern void initial_thread_cb_skas(void (*proc)(void *), void *arg); extern void halt_skas(void); extern void reboot_skas(void); +extern int get_syscall(struct uml_pt_regs *regs); /* irq.c */ extern int os_waiting_for_events(struct irq_fd *active_fds); diff --git a/arch/um/kernel/skas/syscall.c b/arch/um/kernel/skas/syscall.c index d9ec0068b623..64a8fe589d6f 100644 --- a/arch/um/kernel/skas/syscall.c +++ b/arch/um/kernel/skas/syscall.c @@ -8,6 +8,7 @@ #include #include #include +#include extern int syscall_table_size; #define NR_SYSCALLS (syscall_table_size / sizeof(void *)) @@ -23,16 +24,8 @@ void handle_syscall(struct uml_pt_regs *r) goto out; } - /* - * This should go in the declaration of syscall, but when I do that, - * strace -f -c bash -c 'ls ; ls' breaks, sometimes not tracing - * children at all, sometimes hanging when bash doesn't see the first - * ls exit. - * The assembly looks functionally the same to me. This is - * gcc version 4.0.1 20050727 (Red Hat 4.0.1-5) - * in case it's a compiler bug. - */ - syscall = UPT_SYSCALL_NR(r); + syscall = get_syscall(r); + if ((syscall >= NR_SYSCALLS) || (syscall < 0)) result = -ENOSYS; else result = EXECUTE_SYSCALL(syscall, regs); diff --git a/arch/um/os-Linux/skas/process.c b/arch/um/os-Linux/skas/process.c index 3dddedba3a07..d38f4952d748 100644 --- a/arch/um/os-Linux/skas/process.c +++ b/arch/um/os-Linux/skas/process.c @@ -137,9 +137,6 @@ static void handle_trap(int pid, struct uml_pt_regs *regs, if ((UPT_IP(regs) >= STUB_START) && (UPT_IP(regs) < STUB_END)) fatal_sigsegv(); - /* Mark this as a syscall */ - UPT_SYSCALL_NR(regs) = PT_SYSCALL_NR(regs->gp); - if (!local_using_sysemu) { err = ptrace(PTRACE_POKEUSER, pid, PT_SYSCALL_NR_OFFSET, @@ -174,6 +171,13 @@ static void handle_trap(int pid, struct uml_pt_regs *regs, handle_syscall(regs); } +int get_syscall(struct uml_pt_regs *regs) +{ + UPT_SYSCALL_NR(regs) = PT_SYSCALL_NR(regs->gp); + + return UPT_SYSCALL_NR(regs); +} + extern char __syscall_stub_start[]; static int userspace_tramp(void *stack)