parisc: Fix boot failure of 64-bit kernel

Commit c8921d72e390 ("parisc: Fix and improve kernel stack unwinding")
broke booting of 64-bit kernels. On 64-bit kernels function pointers are
actually function descriptors which require dereferencing. In this patch
we instead declare functions in assembly code which are referenced from
C-code as external data pointers with the ENTRY() macro and thus can use
a simple external reference to the functions.

Signed-off-by: Helge Deller <deller@gmx.de>
Fixes: c8921d72e390 ("parisc: Fix and improve kernel stack unwinding")

diff --git a/arch/parisc/include/asm/linkage.h b/arch/parisc/include/asm/linkage.h
index 49f6f3d772cc643b7cced383bf17ec73a6b1fd6b..cd6fe4febeadb34b811ed6b4e0b2caf54971efa5 100644 (file)
--- a/arch/parisc/include/asm/linkage.h
+++ b/arch/parisc/include/asm/linkage.h
@@ -22,15 +22,6 @@
 name:          ASM_NL\
        .export name
 
-#ifdef CONFIG_64BIT
-#define ENDPROC(name) \
-       END(name)
-#else
-#define ENDPROC(name) \
-       .type name, @function !\
-       END(name)
-#endif
-
 #define ENTRY_CFI(name, ...) \
        ENTRY(name)     ASM_NL\
        .proc           ASM_NL\

diff --git a/arch/parisc/kernel/entry.S b/arch/parisc/kernel/entry.S
index e170365941f8e06c55d83039ef1534bfc34472a0..242c5ab6561130e6dd673f9d401485317c59b658 100644 (file)
--- a/arch/parisc/kernel/entry.S
+++ b/arch/parisc/kernel/entry.S
@@ -777,7 +777,7 @@ END(fault_vector_11)
         * copy_thread moved args into task save area.
         */
 
-ENTRY_CFI(ret_from_kernel_thread)
+ENTRY(ret_from_kernel_thread)
        /* Call schedule_tail first though */
        BL      schedule_tail, %r2
        nop
@@ -792,7 +792,7 @@ ENTRY_CFI(ret_from_kernel_thread)
        copy    %r31, %r2
        b       finish_child_return
        nop
-ENDPROC_CFI(ret_from_kernel_thread)
+END(ret_from_kernel_thread)
 
 
        /*
@@ -816,9 +816,8 @@ ENTRY_CFI(_switch_to)
        LDREG   TASK_THREAD_INFO(%r25), %r25
        bv      %r0(%r2)
        mtctl   %r25,%cr30
-ENDPROC_CFI(_switch_to)
 
-ENTRY_CFI(_switch_to_ret)
+ENTRY(_switch_to_ret)
        mtctl   %r0, %cr0               /* Needed for single stepping */
        callee_rest
        callee_rest_float
@@ -826,7 +825,7 @@ ENTRY_CFI(_switch_to_ret)
        LDREG   -RP_OFFSET(%r30), %r2
        bv      %r0(%r2)
        copy    %r26, %r28
-ENDPROC_CFI(_switch_to_ret)
+ENDPROC_CFI(_switch_to)
 
        /*
         * Common rfi return path for interruptions, kernel execve, and
@@ -887,14 +886,12 @@ ENTRY_CFI(syscall_exit_rfi)
        STREG   %r19,PT_SR5(%r16)
        STREG   %r19,PT_SR6(%r16)
        STREG   %r19,PT_SR7(%r16)
-ENDPROC_CFI(syscall_exit_rfi)
 
-ENTRY_CFI(intr_return)
+ENTRY(intr_return)
        /* check for reschedule */
        mfctl   %cr30,%r1
        LDREG   TI_FLAGS(%r1),%r19      /* sched.h: TIF_NEED_RESCHED */
        bb,<,n  %r19,31-TIF_NEED_RESCHED,intr_do_resched /* forward */
-ENDPROC_CFI(intr_return)
 
        .import do_notify_resume,code
 intr_check_sig:
@@ -1050,6 +1047,7 @@ intr_extint:
 
        b       do_cpu_irq_mask
        ldo     R%intr_return(%r2), %r2 /* return to intr_return, not here */
+ENDPROC_CFI(syscall_exit_rfi)
 
 
        /* Generic interruptions (illegal insn, unaligned, page fault, etc) */
@@ -1751,7 +1749,7 @@ fork_like fork
 fork_like vfork
 
        /* Set the return value for the child */
-ENTRY_CFI(child_return)
+ENTRY(child_return)
        BL      schedule_tail, %r2
        nop
 finish_child_return:
@@ -1763,7 +1761,7 @@ finish_child_return:
        reg_restore %r1
        b       syscall_exit
        copy    %r0,%r28
-ENDPROC_CFI(child_return)
+END(child_return)
 
 ENTRY_CFI(sys_rt_sigreturn_wrapper)
        LDREG   TI_TASK-THREAD_SZ_ALGN-FRAME_SIZE(%r30),%r26
@@ -1795,7 +1793,7 @@ ENTRY_CFI(sys_rt_sigreturn_wrapper)
        LDREG   PT_GR28(%r1),%r28  /* reload original r28 for syscall_exit */
 ENDPROC_CFI(sys_rt_sigreturn_wrapper)
 
-ENTRY_CFI(syscall_exit)
+ENTRY(syscall_exit)
        /* NOTE: Not all syscalls exit this way.  rt_sigreturn will exit
         * via syscall_exit_rfi if the signal was received while the process
         * was running.
@@ -1994,15 +1992,13 @@ syscall_do_resched:
 #else
        nop
 #endif
-ENDPROC_CFI(syscall_exit)
+END(syscall_exit)
 
 
 #ifdef CONFIG_FUNCTION_TRACER
 
        .import ftrace_function_trampoline,code
        .align L1_CACHE_BYTES
-       .globl mcount
-       .type  mcount, @function
 ENTRY_CFI(mcount, caller)
 _mcount:
        .export _mcount,data
@@ -2031,8 +2027,6 @@ ENDPROC_CFI(mcount)
 
 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
        .align 8
-       .globl return_to_handler
-       .type  return_to_handler, @function
 ENTRY_CFI(return_to_handler, caller,frame=FRAME_SIZE)
        .export parisc_return_to_handler,data
 parisc_return_to_handler:
@@ -2082,6 +2076,7 @@ ENDPROC_CFI(return_to_handler)
 /* void call_on_stack(unsigned long param1, void *func,
                      unsigned long new_stack) */
 ENTRY_CFI(call_on_stack, FRAME=2*FRAME_SIZE,CALLS,SAVE_RP,SAVE_SP)
+ENTRY(_call_on_stack)
        copy    %sp, %r1
 
        /* Regarding the HPPA calling conventions for function pointers,

diff --git a/arch/parisc/kernel/unwind.c b/arch/parisc/kernel/unwind.c
index 5578a325a73095c63bfb33fc57790f9b50be8fc8..f329b466e68f66acc3f8fb8669de2b92776e29df 100644 (file)
--- a/arch/parisc/kernel/unwind.c
+++ b/arch/parisc/kernel/unwind.c
@@ -209,6 +209,8 @@ static int unwind_special(struct unwind_frame_info *info, unsigned long pc, int
         * We have to use void * instead of a function pointer, because
         * function pointers aren't a pointer to the function on 64-bit.
         * Make them const so the compiler knows they live in .text
+        * Note: We could use dereference_kernel_function_descriptor()
+        * instead but we want to keep it simple here.
         */
        extern void * const handle_interruption;
        extern void * const ret_from_kernel_thread;
@@ -216,7 +218,7 @@ static int unwind_special(struct unwind_frame_info *info, unsigned long pc, int
        extern void * const intr_return;
        extern void * const _switch_to_ret;
 #ifdef CONFIG_IRQSTACKS
-       extern void * const call_on_stack;
+       extern void * const _call_on_stack;
 #endif /* CONFIG_IRQSTACKS */
 
        if (pc == (unsigned long) &handle_interruption) {
@@ -251,7 +253,7 @@ static int unwind_special(struct unwind_frame_info *info, unsigned long pc, int
        }
 
 #ifdef CONFIG_IRQSTACKS
-       if (pc == (unsigned long) &call_on_stack) {
+       if (pc == (unsigned long) &_call_on_stack) {
                info->prev_sp = *(unsigned long *)(info->sp - FRAME_SIZE - REG_SZ);
                info->prev_ip = *(unsigned long *)(info->sp - FRAME_SIZE - RP_OFFSET);
                return 1;