[PATCH 1/6] Hexagon: Signal and return path fixes
From: Richard Kuo
Date: Wed Apr 03 2013 - 20:04:44 EST
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 <rkuo@xxxxxxxxxxxxxx>
---
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 <asm-generic/signal.h>
#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 <linux/tick.h>
#include <linux/uaccess.h>
#include <linux/slab.h>
+#include <linux/tracehook.h>
/*
* 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
--
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