Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758871AbYG0GvT (ORCPT ); Sun, 27 Jul 2008 02:51:19 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755817AbYG0GvI (ORCPT ); Sun, 27 Jul 2008 02:51:08 -0400 Received: from mx1.redhat.com ([66.187.233.31]:35146 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755787AbYG0GvG (ORCPT ); Sun, 27 Jul 2008 02:51:06 -0400 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit From: Roland McGrath To: Paul Mackerras , Benjamin Herrenschmidt X-Fcc: ~/Mail/linus Cc: linuxppc-dev@ozlabs.org, linux-kernel@vger.kernel.org Subject: [PATCH 2/5] powerpc: tracehook syscall In-Reply-To: Roland McGrath's message of Saturday, 26 July 2008 23:48:59 -0700 <20080727064859.69692154280@magilla.localdomain> References: <20080727064859.69692154280@magilla.localdomain> X-Windows: graphics hacking :: Roman numerals : sqrt (pi) Message-Id: <20080727065103.3E894154280@magilla.localdomain> Date: Sat, 26 Jul 2008 23:51:03 -0700 (PDT) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4435 Lines: 136 This changes powerpc syscall tracing to use the new tracehook.h entry points. There is no change, only cleanup. The assembly changes allow do_syscall_trace_enter() to abort the syscall without losing the information about the original r0 value. Signed-off-by: Roland McGrath --- arch/powerpc/kernel/entry_32.S | 7 +++++- arch/powerpc/kernel/entry_64.S | 7 +++++- arch/powerpc/kernel/ptrace.c | 47 ++++++++++++++++++--------------------- 3 files changed, 34 insertions(+), 27 deletions(-) diff --git a/arch/powerpc/kernel/entry_32.S b/arch/powerpc/kernel/entry_32.S index 81c8324..0efc1e6 100644 --- a/arch/powerpc/kernel/entry_32.S +++ b/arch/powerpc/kernel/entry_32.S @@ -343,7 +343,12 @@ syscall_dotrace: stw r0,_TRAP(r1) addi r3,r1,STACK_FRAME_OVERHEAD bl do_syscall_trace_enter - lwz r0,GPR0(r1) /* Restore original registers */ + /* + * Restore argument registers possibly just changed. + * We use the return value of do_syscall_trace_enter + * for call number to look up in the table (r0). + */ + mr r0,r3 lwz r3,GPR3(r1) lwz r4,GPR4(r1) lwz r5,GPR5(r1) diff --git a/arch/powerpc/kernel/entry_64.S b/arch/powerpc/kernel/entry_64.S index d736924..79c089e 100644 --- a/arch/powerpc/kernel/entry_64.S +++ b/arch/powerpc/kernel/entry_64.S @@ -214,7 +214,12 @@ syscall_dotrace: bl .save_nvgprs addi r3,r1,STACK_FRAME_OVERHEAD bl .do_syscall_trace_enter - ld r0,GPR0(r1) /* Restore original registers */ + /* + * Restore argument registers possibly just changed. + * We use the return value of do_syscall_trace_enter + * for the call number to look up in the table (r0). + */ + mr r0,r3 ld r3,GPR3(r1) ld r4,GPR4(r1) ld r5,GPR5(r1) diff --git a/arch/powerpc/kernel/ptrace.c b/arch/powerpc/kernel/ptrace.c index a5d0e78..3f9a942 100644 --- a/arch/powerpc/kernel/ptrace.c +++ b/arch/powerpc/kernel/ptrace.c @@ -22,6 +22,7 @@ #include #include #include +#include #include #include #include @@ -1013,31 +1014,24 @@ long arch_ptrace(struct task_struct *child, long request, long addr, long data) return ret; } -static void do_syscall_trace(void) +/* + * We must return the syscall number to actually look up in the table. + * This can be -1L to skip running any syscall at all. + */ +long do_syscall_trace_enter(struct pt_regs *regs) { - /* the 0x80 provides a way for the tracing parent to distinguish - between a syscall stop and SIGTRAP delivery */ - ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD) - ? 0x80 : 0)); - - /* - * this isn't the same as continuing with a signal, but it will do - * for normal use. strace only continues with a signal if the - * stopping signal is not SIGTRAP. -brl - */ - if (current->exit_code) { - send_sig(current->exit_code, current, 1); - current->exit_code = 0; - } -} + long ret = 0; -void do_syscall_trace_enter(struct pt_regs *regs) -{ secure_computing(regs->gpr[0]); - if (test_thread_flag(TIF_SYSCALL_TRACE) - && (current->ptrace & PT_PTRACED)) - do_syscall_trace(); + if (test_thread_flag(TIF_SYSCALL_TRACE) && + tracehook_report_syscall_entry(regs)) + /* + * Tracing decided this syscall should not happen. + * We'll return a bogus call number to get an ENOSYS + * error, but leave the original number in regs->gpr[0]. + */ + ret = -1L; if (unlikely(current->audit_context)) { #ifdef CONFIG_PPC64 @@ -1055,16 +1049,19 @@ void do_syscall_trace_enter(struct pt_regs *regs) regs->gpr[5] & 0xffffffff, regs->gpr[6] & 0xffffffff); } + + return ret ?: regs->gpr[0]; } void do_syscall_trace_leave(struct pt_regs *regs) { + int step; + if (unlikely(current->audit_context)) audit_syscall_exit((regs->ccr&0x10000000)?AUDITSC_FAILURE:AUDITSC_SUCCESS, regs->result); - if ((test_thread_flag(TIF_SYSCALL_TRACE) - || test_thread_flag(TIF_SINGLESTEP)) - && (current->ptrace & PT_PTRACED)) - do_syscall_trace(); + step = test_thread_flag(TIF_SINGLESTEP); + if (step || test_thread_flag(TIF_SYSCALL_TRACE)) + tracehook_report_syscall_exit(regs, step); } -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/