summaryrefslogtreecommitdiffstats
path: root/arch/xtensa/kernel
diff options
context:
space:
mode:
Diffstat (limited to 'arch/xtensa/kernel')
-rw-r--r--arch/xtensa/kernel/signal.c43
-rw-r--r--arch/xtensa/kernel/vectors.S158
-rw-r--r--arch/xtensa/kernel/vmlinux.lds.S4
3 files changed, 154 insertions, 51 deletions
diff --git a/arch/xtensa/kernel/signal.c b/arch/xtensa/kernel/signal.c
index 98b67d5f1514..4612321c73cc 100644
--- a/arch/xtensa/kernel/signal.c
+++ b/arch/xtensa/kernel/signal.c
@@ -331,17 +331,17 @@ gen_return_code(unsigned char *codemem)
}
-static int setup_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
- sigset_t *set, struct pt_regs *regs)
+static int setup_frame(struct ksignal *ksig, sigset_t *set,
+ struct pt_regs *regs)
{
struct rt_sigframe *frame;
- int err = 0;
+ int err = 0, sig = ksig->sig;
int signal;
unsigned long sp, ra, tp;
sp = regs->areg[1];
- if ((ka->sa.sa_flags & SA_ONSTACK) != 0 && sas_ss_flags(sp) == 0) {
+ if ((ksig->ka.sa.sa_flags & SA_ONSTACK) != 0 && sas_ss_flags(sp) == 0) {
sp = current->sas_ss_sp + current->sas_ss_size;
}
@@ -351,7 +351,7 @@ static int setup_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
panic ("Double exception sys_sigreturn\n");
if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame))) {
- goto give_sigsegv;
+ return -EFAULT;
}
signal = current_thread_info()->exec_domain
@@ -360,8 +360,8 @@ static int setup_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
? current_thread_info()->exec_domain->signal_invmap[sig]
: sig;
- if (ka->sa.sa_flags & SA_SIGINFO) {
- err |= copy_siginfo_to_user(&frame->info, info);
+ if (ksig->ka.sa.sa_flags & SA_SIGINFO) {
+ err |= copy_siginfo_to_user(&frame->info, &ksig->info);
}
/* Create the user context. */
@@ -372,8 +372,8 @@ static int setup_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
err |= setup_sigcontext(frame, regs);
err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
- if (ka->sa.sa_flags & SA_RESTORER) {
- ra = (unsigned long)ka->sa.sa_restorer;
+ if (ksig->ka.sa.sa_flags & SA_RESTORER) {
+ ra = (unsigned long)ksig->ka.sa.sa_restorer;
} else {
/* Create sys_rt_sigreturn syscall in stack frame */
@@ -381,7 +381,7 @@ static int setup_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
err |= gen_return_code(frame->retcode);
if (err) {
- goto give_sigsegv;
+ return -EFAULT;
}
ra = (unsigned long) frame->retcode;
}
@@ -393,7 +393,7 @@ static int setup_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
/* Set up registers for signal handler; preserve the threadptr */
tp = regs->threadptr;
- start_thread(regs, (unsigned long) ka->sa.sa_handler,
+ start_thread(regs, (unsigned long) ksig->ka.sa.sa_handler,
(unsigned long) frame);
/* Set up a stack frame for a call4
@@ -416,10 +416,6 @@ static int setup_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
#endif
return 0;
-
-give_sigsegv:
- force_sigsegv(sig, current);
- return -EFAULT;
}
/*
@@ -433,15 +429,11 @@ give_sigsegv:
*/
static void do_signal(struct pt_regs *regs)
{
- siginfo_t info;
- int signr;
- struct k_sigaction ka;
+ struct ksignal ksig;
task_pt_regs(current)->icountlevel = 0;
- signr = get_signal_to_deliver(&info, &ka, regs, NULL);
-
- if (signr > 0) {
+ if (get_signal(&ksig)) {
int ret;
/* Are we from a system call? */
@@ -457,7 +449,7 @@ static void do_signal(struct pt_regs *regs)
break;
case -ERESTARTSYS:
- if (!(ka.sa.sa_flags & SA_RESTART)) {
+ if (!(ksig.ka.sa.sa_flags & SA_RESTART)) {
regs->areg[2] = -EINTR;
break;
}
@@ -476,11 +468,8 @@ static void do_signal(struct pt_regs *regs)
/* Whee! Actually deliver the signal. */
/* Set up the stack frame */
- ret = setup_frame(signr, &ka, &info, sigmask_to_save(), regs);
- if (ret)
- return;
-
- signal_delivered(signr, &info, &ka, regs, 0);
+ ret = setup_frame(&ksig, sigmask_to_save(), regs);
+ signal_setup_done(ret, &ksig, 0);
if (current->ptrace & PT_SINGLESTEP)
task_pt_regs(current)->icountlevel = 1;
diff --git a/arch/xtensa/kernel/vectors.S b/arch/xtensa/kernel/vectors.S
index f9e1ec346e35..8453e6e39895 100644
--- a/arch/xtensa/kernel/vectors.S
+++ b/arch/xtensa/kernel/vectors.S
@@ -376,38 +376,42 @@ _DoubleExceptionVector_WindowOverflow:
beqz a2, 1f # if at start of vector, don't restore
addi a0, a0, -128
- bbsi a0, 8, 1f # don't restore except for overflow 8 and 12
- bbsi a0, 7, 2f
+ bbsi.l a0, 8, 1f # don't restore except for overflow 8 and 12
+
+ /*
+ * This fixup handler is for the extremely unlikely case where the
+ * overflow handler's reference thru a0 gets a hardware TLB refill
+ * that bumps out the (distinct, aliasing) TLB entry that mapped its
+ * prior references thru a9/a13, and where our reference now thru
+ * a9/a13 gets a 2nd-level miss exception (not hardware TLB refill).
+ */
+ movi a2, window_overflow_restore_a0_fixup
+ s32i a2, a3, EXC_TABLE_FIXUP
+ l32i a2, a3, EXC_TABLE_DOUBLE_SAVE
+ xsr a3, excsave1
+
+ bbsi.l a0, 7, 2f
/*
* Restore a0 as saved by _WindowOverflow8().
- *
- * FIXME: we really need a fixup handler for this L32E,
- * for the extremely unlikely case where the overflow handler's
- * reference thru a0 gets a hardware TLB refill that bumps out
- * the (distinct, aliasing) TLB entry that mapped its prior
- * references thru a9, and where our reference now thru a9
- * gets a 2nd-level miss exception (not hardware TLB refill).
*/
- l32e a2, a9, -16
- wsr a2, depc # replace the saved a0
- j 1f
+ l32e a0, a9, -16
+ wsr a0, depc # replace the saved a0
+ j 3f
2:
/*
* Restore a0 as saved by _WindowOverflow12().
- *
- * FIXME: we really need a fixup handler for this L32E,
- * for the extremely unlikely case where the overflow handler's
- * reference thru a0 gets a hardware TLB refill that bumps out
- * the (distinct, aliasing) TLB entry that mapped its prior
- * references thru a13, and where our reference now thru a13
- * gets a 2nd-level miss exception (not hardware TLB refill).
*/
- l32e a2, a13, -16
- wsr a2, depc # replace the saved a0
+ l32e a0, a13, -16
+ wsr a0, depc # replace the saved a0
+3:
+ xsr a3, excsave1
+ movi a0, 0
+ s32i a0, a3, EXC_TABLE_FIXUP
+ s32i a2, a3, EXC_TABLE_DOUBLE_SAVE
1:
/*
* Restore WindowBase while leaving all address registers restored.
@@ -449,6 +453,7 @@ _DoubleExceptionVector_WindowOverflow:
s32i a0, a2, PT_DEPC
+_DoubleExceptionVector_handle_exception:
addx4 a0, a0, a3
l32i a0, a0, EXC_TABLE_FAST_USER
xsr a3, excsave1
@@ -464,11 +469,120 @@ _DoubleExceptionVector_WindowOverflow:
rotw -3
j 1b
- .end literal_prefix
ENDPROC(_DoubleExceptionVector)
/*
+ * Fixup handler for TLB miss in double exception handler for window owerflow.
+ * We get here with windowbase set to the window that was being spilled and
+ * a0 trashed. a0 bit 7 determines if this is a call8 (bit clear) or call12
+ * (bit set) window.
+ *
+ * We do the following here:
+ * - go to the original window retaining a0 value;
+ * - set up exception stack to return back to appropriate a0 restore code
+ * (we'll need to rotate window back and there's no place to save this
+ * information, use different return address for that);
+ * - handle the exception;
+ * - go to the window that was being spilled;
+ * - set up window_overflow_restore_a0_fixup as a fixup routine;
+ * - reload a0;
+ * - restore the original window;
+ * - reset the default fixup routine;
+ * - return to user. By the time we get to this fixup handler all information
+ * about the conditions of the original double exception that happened in
+ * the window overflow handler is lost, so we just return to userspace to
+ * retry overflow from start.
+ *
+ * a0: value of depc, original value in depc
+ * a2: trashed, original value in EXC_TABLE_DOUBLE_SAVE
+ * a3: exctable, original value in excsave1
+ */
+
+ENTRY(window_overflow_restore_a0_fixup)
+
+ rsr a0, ps
+ extui a0, a0, PS_OWB_SHIFT, PS_OWB_WIDTH
+ rsr a2, windowbase
+ sub a0, a2, a0
+ extui a0, a0, 0, 3
+ l32i a2, a3, EXC_TABLE_DOUBLE_SAVE
+ xsr a3, excsave1
+
+ _beqi a0, 1, .Lhandle_1
+ _beqi a0, 3, .Lhandle_3
+
+ .macro overflow_fixup_handle_exception_pane n
+
+ rsr a0, depc
+ rotw -\n
+
+ xsr a3, excsave1
+ wsr a2, depc
+ l32i a2, a3, EXC_TABLE_KSTK
+ s32i a0, a2, PT_AREG0
+
+ movi a0, .Lrestore_\n
+ s32i a0, a2, PT_DEPC
+ rsr a0, exccause
+ j _DoubleExceptionVector_handle_exception
+
+ .endm
+
+ overflow_fixup_handle_exception_pane 2
+.Lhandle_1:
+ overflow_fixup_handle_exception_pane 1
+.Lhandle_3:
+ overflow_fixup_handle_exception_pane 3
+
+ .macro overflow_fixup_restore_a0_pane n
+
+ rotw \n
+ /* Need to preserve a0 value here to be able to handle exception
+ * that may occur on a0 reload from stack. It may occur because
+ * TLB miss handler may not be atomic and pointer to page table
+ * may be lost before we get here. There are no free registers,
+ * so we need to use EXC_TABLE_DOUBLE_SAVE area.
+ */
+ xsr a3, excsave1
+ s32i a2, a3, EXC_TABLE_DOUBLE_SAVE
+ movi a2, window_overflow_restore_a0_fixup
+ s32i a2, a3, EXC_TABLE_FIXUP
+ l32i a2, a3, EXC_TABLE_DOUBLE_SAVE
+ xsr a3, excsave1
+ bbsi.l a0, 7, 1f
+ l32e a0, a9, -16
+ j 2f
+1:
+ l32e a0, a13, -16
+2:
+ rotw -\n
+
+ .endm
+
+.Lrestore_2:
+ overflow_fixup_restore_a0_pane 2
+
+.Lset_default_fixup:
+ xsr a3, excsave1
+ s32i a2, a3, EXC_TABLE_DOUBLE_SAVE
+ movi a2, 0
+ s32i a2, a3, EXC_TABLE_FIXUP
+ l32i a2, a3, EXC_TABLE_DOUBLE_SAVE
+ xsr a3, excsave1
+ rfe
+
+.Lrestore_1:
+ overflow_fixup_restore_a0_pane 1
+ j .Lset_default_fixup
+.Lrestore_3:
+ overflow_fixup_restore_a0_pane 3
+ j .Lset_default_fixup
+
+ENDPROC(window_overflow_restore_a0_fixup)
+
+ .end literal_prefix
+/*
* Debug interrupt vector
*
* There is not much space here, so simply jump to another handler.
diff --git a/arch/xtensa/kernel/vmlinux.lds.S b/arch/xtensa/kernel/vmlinux.lds.S
index ee32c0085dff..d16db6df86f8 100644
--- a/arch/xtensa/kernel/vmlinux.lds.S
+++ b/arch/xtensa/kernel/vmlinux.lds.S
@@ -269,13 +269,13 @@ SECTIONS
.UserExceptionVector.literal)
SECTION_VECTOR (_DoubleExceptionVector_literal,
.DoubleExceptionVector.literal,
- DOUBLEEXC_VECTOR_VADDR - 16,
+ DOUBLEEXC_VECTOR_VADDR - 40,
SIZEOF(.UserExceptionVector.text),
.UserExceptionVector.text)
SECTION_VECTOR (_DoubleExceptionVector_text,
.DoubleExceptionVector.text,
DOUBLEEXC_VECTOR_VADDR,
- 32,
+ 40,
.DoubleExceptionVector.literal)
. = (LOADADDR( .DoubleExceptionVector.text ) + SIZEOF( .DoubleExceptionVector.text ) + 3) & ~ 3;
OpenPOWER on IntegriCloud