Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1763024Ab3DDAEm (ORCPT ); Wed, 3 Apr 2013 20:04:42 -0400 Received: from wolverine02.qualcomm.com ([199.106.114.251]:4834 "EHLO wolverine02.qualcomm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1762220Ab3DDADR (ORCPT ); Wed, 3 Apr 2013 20:03:17 -0400 X-IronPort-AV: E=Sophos;i="4.87,404,1363158000"; d="scan'208";a="35720033" From: Richard Kuo To: linux-arch@vger.kernel.org, linux-hexagon@vger.kernel.org, linux-kernel@vger.kernel.org, viro@ZenIV.linux.org.uk Cc: Richard Kuo Subject: [PATCH 1/6] Hexagon: Signal and return path fixes Date: Wed, 3 Apr 2013 19:02:51 -0500 Message-Id: <1365033776-21804-2-git-send-email-rkuo@codeaurora.org> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: <1365033776-21804-1-git-send-email-rkuo@codeaurora.org> References: <1365033776-21804-1-git-send-email-rkuo@codeaurora.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 9334 Lines: 327 This fixes the return value of sigreturn and moves the work pending check into a c routine for readability and fixes the loop for multiple pending signals. Based on feedback from Al Viro. Signed-off-by: Richard Kuo --- arch/hexagon/include/uapi/asm/signal.h | 2 + arch/hexagon/kernel/process.c | 41 +++++++++++++++ arch/hexagon/kernel/signal.c | 29 ++--------- arch/hexagon/kernel/traps.c | 13 +---- arch/hexagon/kernel/vm_entry.S | 87 +++++++++++++------------------- 5 files changed, 84 insertions(+), 88 deletions(-) diff --git a/arch/hexagon/include/uapi/asm/signal.h b/arch/hexagon/include/uapi/asm/signal.h index 9395568..24b9988 100644 --- a/arch/hexagon/include/uapi/asm/signal.h +++ b/arch/hexagon/include/uapi/asm/signal.h @@ -21,6 +21,8 @@ extern unsigned long __rt_sigtramp_template[2]; +void do_signal(struct pt_regs *regs); + #include #endif diff --git a/arch/hexagon/kernel/process.c b/arch/hexagon/kernel/process.c index 06ae9ff..dc72ed5 100644 --- a/arch/hexagon/kernel/process.c +++ b/arch/hexagon/kernel/process.c @@ -24,6 +24,7 @@ #include #include #include +#include /* * Program thread launch. Often defined as a macro in processor.h, @@ -202,3 +203,43 @@ int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpu) { return 0; } + + +/* + * Called on the exit path of event entry; see vm_entry.S + * + * Interrupts will already be disabled. + * + * Returns 0 if there's no need to re-check for more work. + */ + +int do_work_pending(struct pt_regs *regs, u32 thread_info_flags) +{ + if (!(thread_info_flags & _TIF_ALLWORK_MASK)) { + return 0; + } /* shortcut -- no work to be done */ + + local_irq_enable(); + + if (thread_info_flags & _TIF_NEED_RESCHED) { + schedule(); + return 1; + } + + if (thread_info_flags & _TIF_SIGPENDING) { + do_signal(regs); + return 1; + } + + if (thread_info_flags & _TIF_NOTIFY_RESUME) { + clear_thread_flag(TIF_NOTIFY_RESUME); + tracehook_notify_resume(regs); + if (current->replacement_session_keyring) + key_replace_session_keyring(); + return 1; + } + + /* Should not even reach here */ + panic("%s: bad thread_info flags 0x%08x\n", __func__, + thread_info_flags); +} diff --git a/arch/hexagon/kernel/signal.c b/arch/hexagon/kernel/signal.c index a1492a6..8a20e8e 100644 --- a/arch/hexagon/kernel/signal.c +++ b/arch/hexagon/kernel/signal.c @@ -199,7 +199,7 @@ static void handle_signal(int sig, siginfo_t *info, struct k_sigaction *ka, /* * Called from return-from-event code. */ -static void do_signal(struct pt_regs *regs) +void do_signal(struct pt_regs *regs) { struct k_sigaction sigact; siginfo_t info; @@ -216,8 +216,9 @@ static void do_signal(struct pt_regs *regs) } /* - * If we came from a system call, handle the restart. + * No (more) signals; if we came from a system call, handle the restart. */ + if (regs->syscall_nr >= 0) { switch (regs->r00) { case -ERESTARTNOHAND: @@ -240,17 +241,6 @@ no_restart: restore_saved_sigmask(); } -void do_notify_resume(struct pt_regs *regs, unsigned long thread_info_flags) -{ - if (thread_info_flags & _TIF_SIGPENDING) - do_signal(regs); - - if (thread_info_flags & _TIF_NOTIFY_RESUME) { - clear_thread_flag(TIF_NOTIFY_RESUME); - tracehook_notify_resume(regs); - } -} - /* * Architecture-specific wrappers for signal-related system calls */ @@ -278,21 +268,12 @@ asmlinkage int sys_rt_sigreturn(void) /* Restore the user's stack as well */ pt_psp(regs) = regs->r29; - /* - * Leave a trace in the stack frame that this was a sigreturn. - * If the system call is to replay, we've already restored the - * number in the GPR slot and it will be regenerated on the - * new system call trap entry. Note that if restore_sigcontext() - * did something other than a bulk copy of the pt_regs struct, - * we could avoid this assignment by simply not overwriting - * regs->syscall_nr. - */ - regs->syscall_nr = __NR_rt_sigreturn; + regs->syscall_nr = -1; if (restore_altstack(&frame->uc.uc_stack)) goto badframe; - return 0; + return regs->r00; badframe: force_sig(SIGSEGV, current); diff --git a/arch/hexagon/kernel/traps.c b/arch/hexagon/kernel/traps.c index be5e2dd..d59ee62 100644 --- a/arch/hexagon/kernel/traps.c +++ b/arch/hexagon/kernel/traps.c @@ -356,7 +356,6 @@ long sys_syscall(void) void do_trap0(struct pt_regs *regs) { - unsigned long syscallret = 0; syscall_fn syscall; switch (pt_cause(regs)) { @@ -396,21 +395,11 @@ void do_trap0(struct pt_regs *regs) } else { syscall = (syscall_fn) (sys_call_table[regs->syscall_nr]); - syscallret = syscall(regs->r00, regs->r01, + regs->r00 = syscall(regs->r00, regs->r01, regs->r02, regs->r03, regs->r04, regs->r05); } - /* - * If it was a sigreturn system call, don't overwrite - * r0 value in stack frame with return value. - * - * __NR_sigreturn doesn't seem to exist in new unistd.h - */ - - if (regs->syscall_nr != __NR_rt_sigreturn) - regs->r00 = syscallret; - /* allow strace to get the syscall return state */ if (unlikely(test_thread_flag(TIF_SYSCALL_TRACE))) tracehook_report_syscall_exit(regs, 0); diff --git a/arch/hexagon/kernel/vm_entry.S b/arch/hexagon/kernel/vm_entry.S index ffe4a42..053551e 100644 --- a/arch/hexagon/kernel/vm_entry.S +++ b/arch/hexagon/kernel/vm_entry.S @@ -274,6 +274,9 @@ event_dispatch: callr r1 /* + * Coming back from the C-world, our thread info pointer + * should be in the designated register (usually R19) + * * If we were in kernel mode, we don't need to check scheduler * or signals if CONFIG_PREEMPT is not set. If set, then it has * to jump to a need_resched kind of block. @@ -286,67 +289,43 @@ event_dispatch: #endif /* "Nested control path" -- if the previous mode was kernel */ - R0 = memw(R29 + #_PT_ER_VMEST); { - P0 = tstbit(R0, #HVM_VMEST_UM_SFT); - if (!P0.new) jump:nt restore_all; + R0 = memw(R29 + #_PT_ER_VMEST); + R16.L = #LO(do_work_pending); } - /* - * Returning from system call, normally coming back from user mode - */ -return_from_syscall: - /* Disable interrupts while checking TIF */ - R0 = #VM_INT_DISABLE - trap1(#HVM_TRAP1_VMSETIE) - - /* - * Coming back from the C-world, our thread info pointer - * should be in the designated register (usually R19) - */ -#if CONFIG_HEXAGON_ARCH_VERSION < 4 - R1.L = #LO(_TIF_ALLWORK_MASK) { - R1.H = #HI(_TIF_ALLWORK_MASK); - R0 = memw(THREADINFO_REG + #_THREAD_INFO_FLAGS); - } -#else - { - R1 = ##_TIF_ALLWORK_MASK; - R0 = memw(THREADINFO_REG + #_THREAD_INFO_FLAGS); + P0 = tstbit(R0, #HVM_VMEST_UM_SFT); + if (!P0.new) jump:nt restore_all; + R16.H = #HI(do_work_pending); + R0 = #VM_INT_DISABLE; } -#endif /* - * Compare against the "return to userspace" _TIF_WORK_MASK + * Check also the return from fork/system call, normally coming back from + * user mode + * + * R16 needs to have do_work_pending, and R0 should have VM_INT_DISABLE */ - R1 = and(R1,R0); - { P0 = cmp.eq(R1,#0); if (!P0.new) jump:t work_pending;} - jump restore_all; /* we're outta here! */ -work_pending: +check_work_pending: + /* Disable interrupts while checking TIF */ + trap1(#HVM_TRAP1_VMSETIE) { - P0 = tstbit(R1, #TIF_NEED_RESCHED); - if (!P0.new) jump:nt work_notifysig; + R0 = R29; /* regs should still be at top of stack */ + R1 = memw(THREADINFO_REG + #_THREAD_INFO_FLAGS); + callr R16; } - call schedule - jump return_from_syscall; /* check for more work */ -work_notifysig: - /* this is the part that's kind of fuzzy. */ - R1 = and(R0, #(_TIF_SIGPENDING | _TIF_NOTIFY_RESUME)); - { - P0 = cmp.eq(R1, #0); - if P0.new jump:t restore_all; - } { - R1 = R0; /* unsigned long thread_info_flags */ - R0 = R29; /* regs should still be at top of stack */ + P0 = cmp.eq(R0, #0); if (!P0.new) jump:nt check_work_pending; + R0 = #VM_INT_DISABLE; } - call do_notify_resume restore_all: - /* Disable interrupts, if they weren't already, before reg restore. */ - R0 = #VM_INT_DISABLE + /* + * Disable interrupts, if they weren't already, before reg restore. + * R0 gets preloaded with #VM_INT_DISABLE before we get here. + */ trap1(#HVM_TRAP1_VMSETIE) /* do the setregs here for VM 0.5 */ @@ -371,6 +350,7 @@ restore_all: trap1(#HVM_TRAP1_VMRTE) /* Notreached */ + .globl _K_enter_genex _K_enter_genex: vm_event_entry(do_genex) @@ -390,9 +370,12 @@ _K_enter_machcheck: .globl ret_from_fork ret_from_fork: - call schedule_tail - P0 = cmp.eq(R24, #0); - if P0 jump return_from_syscall - R0 = R25; - callr R24 - jump return_from_syscall + { + call schedule_tail; + R16.H = #HI(do_work_pending); + } + { + R16.L = #LO(do_work_pending); + R0 = #VM_INT_DISABLE; + jump check_work_pending; + } -- 1.7.9.5 -- Sent by an employee of the Qualcomm Innovation Center, Inc. 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