parisc: Fix and improve kernel stack unwinding

This patchset fixes and improves stack unwinding a lot:
1. Show backward stack traces with up to 30 callsites
2. Add callinfo to ENTRY_CFI() such that every assembler function will get an
   entry in the unwind table
3. Use constants instead of numbers in call_on_stack()
4. Do not depend on CONFIG_KALLSYMS to generate backtraces.
5. Speed up backtrace generation

Make sure you have this patch to GNU as installed:
https://sourceware.org/ml/binutils/2018-07/msg00474.html
Without this patch, unwind info in the kernel is often wrong for various
functions.

Signed-off-by: Helge Deller <deller@gmx.de>

10 files changed, 88 insertions, 232 deletions

diff --git a/arch/parisc/include/asm/assembly.h b/arch/parisc/include/asm/assembly.h
index 60e6f07b7e32..e9c6385ef0d1 100644
--- a/arch/parisc/include/asm/assembly.h
+++ b/arch/parisc/include/asm/assembly.h
@@ -36,6 +36,7 @@
 #define RP_OFFSET       16
 #define FRAME_SIZE      128
 #define CALLEE_REG_FRAME_SIZE   144
+#define REG_SZ          8
 #define ASM_ULONG_INSN  .dword
 #else   /* CONFIG_64BIT */
 #define LDREG   ldw
@@ -50,6 +51,7 @@
 #define RP_OFFSET       20
 #define FRAME_SIZE      64
 #define CALLEE_REG_FRAME_SIZE   128
+#define REG_SZ          4
 #define ASM_ULONG_INSN  .word
 #endif
 
diff --git a/arch/parisc/include/asm/linkage.h b/arch/parisc/include/asm/linkage.h
index 9a69bf6fc4b6..49f6f3d772cc 100644
--- a/arch/parisc/include/asm/linkage.h
+++ b/arch/parisc/include/asm/linkage.h
@@ -18,9 +18,9 @@
 #ifdef __ASSEMBLY__
 
 #define ENTRY(name) \
-        .export name !\
-        ALIGN !\
-name:
+        ALIGN   !\
+name:           ASM_NL\
+        .export name
 
 #ifdef CONFIG_64BIT
 #define ENDPROC(name) \
@@ -31,13 +31,18 @@ name:
         END(name)
 #endif
 
-#define ENTRY_CFI(name) \
+#define ENTRY_CFI(name, ...) \
         ENTRY(name)     ASM_NL\
+        .proc           ASM_NL\
+        .callinfo __VA_ARGS__   ASM_NL\
+        .entry          ASM_NL\
         CFI_STARTPROC
 
 #define ENDPROC_CFI(name) \
-        ENDPROC(name)   ASM_NL\
-        CFI_ENDPROC
+        CFI_ENDPROC     ASM_NL\
+        .exit           ASM_NL\
+        .procend        ASM_NL\
+        ENDPROC(name)
 
 #endif /* __ASSEMBLY__ */
 
diff --git a/arch/parisc/include/asm/unwind.h b/arch/parisc/include/asm/unwind.h
index c73a3ee20226..f133b7efbebb 100644
--- a/arch/parisc/include/asm/unwind.h
+++ b/arch/parisc/include/asm/unwind.h
@@ -4,6 +4,9 @@
 
 #include <linux/list.h>
 
+/* Max number of levels to backtrace */
+#define MAX_UNWIND_ENTRIES      30
+
 /* From ABI specifications */
 struct unwind_table_entry {
         unsigned int region_start;
diff --git a/arch/parisc/kernel/entry.S b/arch/parisc/kernel/entry.S
index 1b4732e20137..c7508f5717fb 100644
--- a/arch/parisc/kernel/entry.S
+++ b/arch/parisc/kernel/entry.S
@@ -766,7 +766,6 @@ END(fault_vector_11)
 #endif
         /* Fault vector is separately protected and *must* be on its own page */
         .align          PAGE_SIZE
-ENTRY(end_fault_vector)
 
         .import         handle_interruption,code
         .import         do_cpu_irq_mask,code
@@ -778,7 +777,6 @@ ENTRY(end_fault_vector)
          */
 
 ENTRY_CFI(ret_from_kernel_thread)
-
         /* Call schedule_tail first though */
         BL      schedule_tail, %r2
         nop
@@ -817,8 +815,9 @@ ENTRY_CFI(_switch_to)
         LDREG   TASK_THREAD_INFO(%r25), %r25
         bv      %r0(%r2)
         mtctl   %r25,%cr30
+ENDPROC_CFI(_switch_to)
 
-_switch_to_ret:
+ENTRY_CFI(_switch_to_ret)
         mtctl   %r0, %cr0               /* Needed for single stepping */
         callee_rest
         callee_rest_float
@@ -826,7 +825,7 @@ _switch_to_ret:
         LDREG   -RP_OFFSET(%r30), %r2
         bv      %r0(%r2)
         copy    %r26, %r28
-ENDPROC_CFI(_switch_to)
+ENDPROC_CFI(_switch_to_ret)
 
         /*
          * Common rfi return path for interruptions, kernel execve, and
@@ -887,12 +886,14 @@ 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)
 
-intr_return:
+ENTRY_CFI(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:
@@ -1048,7 +1049,6 @@ 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) */
@@ -1999,12 +1999,9 @@ ENDPROC_CFI(syscall_exit)
         .align L1_CACHE_BYTES
         .globl mcount
         .type  mcount, @function
-ENTRY(mcount)
+ENTRY_CFI(mcount, caller)
 _mcount:
         .export _mcount,data
-        .proc
-        .callinfo caller,frame=0
-        .entry
         /*
          * The 64bit mcount() function pointer needs 4 dwords, of which the
          * first two are free.  We optimize it here and put 2 instructions for
@@ -2026,18 +2023,13 @@ ftrace_stub:
         .dword mcount
         .dword 0 /* code in head.S puts value of global gp here */
 #endif
-        .exit
-        .procend
-ENDPROC(mcount)
+ENDPROC_CFI(mcount)
 
 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
         .align 8
         .globl return_to_handler
         .type  return_to_handler, @function
-ENTRY_CFI(return_to_handler)
-        .proc
-        .callinfo caller,frame=FRAME_SIZE
-        .entry
+ENTRY_CFI(return_to_handler, caller,frame=FRAME_SIZE)
         .export parisc_return_to_handler,data
 parisc_return_to_handler:
         copy %r3,%r1
@@ -2076,8 +2068,6 @@ parisc_return_to_handler:
         bv      %r0(%rp)
 #endif
         LDREGM -FRAME_SIZE(%sp),%r3
-        .exit
-        .procend
 ENDPROC_CFI(return_to_handler)
 
 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
@@ -2087,31 +2077,30 @@ ENDPROC_CFI(return_to_handler)
 #ifdef CONFIG_IRQSTACKS
 /* void call_on_stack(unsigned long param1, void *func,
                       unsigned long new_stack) */
-ENTRY_CFI(call_on_stack)
+ENTRY_CFI(call_on_stack, FRAME=2*FRAME_SIZE,CALLS,SAVE_RP,SAVE_SP)
         copy    %sp, %r1
 
         /* Regarding the HPPA calling conventions for function pointers,
            we assume the PIC register is not changed across call.  For
            CONFIG_64BIT, the argument pointer is left to point at the
            argument region allocated for the call to call_on_stack. */
+
+        /* Switch to new stack.  We allocate two frames.  */
+        ldo     2*FRAME_SIZE(%arg2), %sp
 # ifdef CONFIG_64BIT
-        /* Switch to new stack.  We allocate two 128 byte frames.  */
-        ldo     256(%arg2), %sp
         /* Save previous stack pointer and return pointer in frame marker */
-        STREG   %rp, -144(%sp)
+        STREG   %rp, -FRAME_SIZE-RP_OFFSET(%sp)
         /* Calls always use function descriptor */
         LDREG   16(%arg1), %arg1
         bve,l   (%arg1), %rp
-        STREG   %r1, -136(%sp)
-        LDREG   -144(%sp), %rp
+        STREG   %r1, -FRAME_SIZE-REG_SZ(%sp)
+        LDREG   -FRAME_SIZE-RP_OFFSET(%sp), %rp
         bve     (%rp)
-        LDREG   -136(%sp), %sp
+        LDREG   -FRAME_SIZE-REG_SZ(%sp), %sp
 # else
-        /* Switch to new stack.  We allocate two 64 byte frames.  */
-        ldo     128(%arg2), %sp
         /* Save previous stack pointer and return pointer in frame marker */
-        STREG   %r1, -68(%sp)
-        STREG   %rp, -84(%sp)
+        STREG   %r1, -FRAME_SIZE-REG_SZ(%sp)
+        STREG   %rp, -FRAME_SIZE-RP_OFFSET(%sp)
         /* Calls use function descriptor if PLABEL bit is set */
         bb,>=,n %arg1, 30, 1f
         depwi   0,31,2, %arg1
@@ -2119,9 +2108,9 @@ ENTRY_CFI(call_on_stack)
 1:
         be,l    0(%sr4,%arg1), %sr0, %r31
         copy    %r31, %rp
-        LDREG   -84(%sp), %rp
+        LDREG   -FRAME_SIZE-RP_OFFSET(%sp), %rp
         bv      (%rp)
-        LDREG   -68(%sp), %sp
+        LDREG   -FRAME_SIZE-REG_SZ(%sp), %sp
 # endif /* CONFIG_64BIT */
 ENDPROC_CFI(call_on_stack)
 #endif /* CONFIG_IRQSTACKS */
diff --git a/arch/parisc/kernel/pacache.S b/arch/parisc/kernel/pacache.S
index 97451e67d35b..f33bf2d306d6 100644
--- a/arch/parisc/kernel/pacache.S
+++ b/arch/parisc/kernel/pacache.S
@@ -44,10 +44,6 @@
         .align  16
 
 ENTRY_CFI(flush_tlb_all_local)
-        .proc
-        .callinfo NO_CALLS
-        .entry
-
         /*
          * The pitlbe and pdtlbe instructions should only be used to
          * flush the entire tlb. Also, there needs to be no intervening
@@ -189,18 +185,11 @@ fdtdone:
 
 2:      bv              %r0(%r2)
         nop
-
-        .exit
-        .procend
 ENDPROC_CFI(flush_tlb_all_local)
 
         .import cache_info,data
 
 ENTRY_CFI(flush_instruction_cache_local)
-        .proc
-        .callinfo NO_CALLS
-        .entry
-
         load32          cache_info, %r1
 
         /* Flush Instruction Cache */
@@ -256,18 +245,11 @@ fisync:
         mtsm            %r22                    /* restore I-bit */
         bv              %r0(%r2)
         nop
-        .exit
-
-        .procend
 ENDPROC_CFI(flush_instruction_cache_local)
 
 
         .import cache_info, data
 ENTRY_CFI(flush_data_cache_local)
-        .proc
-        .callinfo NO_CALLS
-        .entry
-
         load32          cache_info, %r1
 
         /* Flush Data Cache */
@@ -324,9 +306,6 @@ fdsync:
         mtsm            %r22                    /* restore I-bit */
         bv              %r0(%r2)
         nop
-        .exit
-
-        .procend
 ENDPROC_CFI(flush_data_cache_local)
 
 /* Macros to serialize TLB purge operations on SMP.  */
@@ -362,10 +341,6 @@ ENDPROC_CFI(flush_data_cache_local)
 /* Clear page using kernel mapping.  */
 
 ENTRY_CFI(clear_page_asm)
-        .proc
-        .callinfo NO_CALLS
-        .entry
-
 #ifdef CONFIG_64BIT
 
         /* Unroll the loop.  */
@@ -424,18 +399,11 @@ ENTRY_CFI(clear_page_asm)
 #endif
         bv              %r0(%r2)
         nop
-        .exit
-
-        .procend
 ENDPROC_CFI(clear_page_asm)
 
 /* Copy page using kernel mapping.  */
 
 ENTRY_CFI(copy_page_asm)
-        .proc
-        .callinfo NO_CALLS
-        .entry
-
 #ifdef CONFIG_64BIT
         /* PA8x00 CPUs can consume 2 loads or 1 store per cycle.
          * Unroll the loop by hand and arrange insn appropriately.
@@ -542,9 +510,6 @@ ENTRY_CFI(copy_page_asm)
 #endif
         bv              %r0(%r2)
         nop
-        .exit
-
-        .procend
 ENDPROC_CFI(copy_page_asm)
 
 /*
@@ -598,10 +563,6 @@ ENDPROC_CFI(copy_page_asm)
          */
 
 ENTRY_CFI(copy_user_page_asm)
-        .proc
-        .callinfo NO_CALLS
-        .entry
-
         /* Convert virtual `to' and `from' addresses to physical addresses.
            Move `from' physical address to non shadowed register.  */
         ldil            L%(__PAGE_OFFSET), %r1
@@ -750,16 +711,9 @@ ENTRY_CFI(copy_user_page_asm)
 
         bv              %r0(%r2)
         nop
-        .exit
-
-        .procend
 ENDPROC_CFI(copy_user_page_asm)
 
 ENTRY_CFI(clear_user_page_asm)
-        .proc
-        .callinfo NO_CALLS
-        .entry
-
         tophys_r1       %r26
 
         ldil            L%(TMPALIAS_MAP_START), %r28
@@ -836,16 +790,9 @@ ENTRY_CFI(clear_user_page_asm)
 
         bv              %r0(%r2)
         nop
-        .exit
-
-        .procend
 ENDPROC_CFI(clear_user_page_asm)
 
 ENTRY_CFI(flush_dcache_page_asm)
-        .proc
-        .callinfo NO_CALLS
-        .entry
-
         ldil            L%(TMPALIAS_MAP_START), %r28
 #ifdef CONFIG_64BIT
 #if (TMPALIAS_MAP_START >= 0x80000000)
@@ -903,16 +850,9 @@ ENTRY_CFI(flush_dcache_page_asm)
         sync
         bv              %r0(%r2)
         nop
-        .exit
-
-        .procend
 ENDPROC_CFI(flush_dcache_page_asm)
 
 ENTRY_CFI(flush_icache_page_asm)
-        .proc
-        .callinfo NO_CALLS
-        .entry
-
         ldil            L%(TMPALIAS_MAP_START), %r28
 #ifdef CONFIG_64BIT
 #if (TMPALIAS_MAP_START >= 0x80000000)
@@ -977,16 +917,9 @@ ENTRY_CFI(flush_icache_page_asm)
         sync
         bv              %r0(%r2)
         nop
-        .exit
-
-        .procend
 ENDPROC_CFI(flush_icache_page_asm)
 
 ENTRY_CFI(flush_kernel_dcache_page_asm)
-        .proc
-        .callinfo NO_CALLS
-        .entry
-
         ldil            L%dcache_stride, %r1
         ldw             R%dcache_stride(%r1), %r23
 
@@ -1020,16 +953,9 @@ ENTRY_CFI(flush_kernel_dcache_page_asm)
         sync
         bv              %r0(%r2)
         nop
-        .exit
-
-        .procend
 ENDPROC_CFI(flush_kernel_dcache_page_asm)
 
 ENTRY_CFI(purge_kernel_dcache_page_asm)
-        .proc
-        .callinfo NO_CALLS
-        .entry
-
         ldil            L%dcache_stride, %r1
         ldw             R%dcache_stride(%r1), %r23
 
@@ -1062,16 +988,9 @@ ENTRY_CFI(purge_kernel_dcache_page_asm)
         sync
         bv              %r0(%r2)
         nop
-        .exit
-
-        .procend
 ENDPROC_CFI(purge_kernel_dcache_page_asm)
 
 ENTRY_CFI(flush_user_dcache_range_asm)
-        .proc
-        .callinfo NO_CALLS
-        .entry
-
         ldil            L%dcache_stride, %r1
         ldw             R%dcache_stride(%r1), %r23
         ldo             -1(%r23), %r21
@@ -1083,16 +1002,9 @@ ENTRY_CFI(flush_user_dcache_range_asm)
         sync
         bv              %r0(%r2)
         nop
-        .exit
-
-        .procend
 ENDPROC_CFI(flush_user_dcache_range_asm)
 
 ENTRY_CFI(flush_kernel_dcache_range_asm)
-        .proc
-        .callinfo NO_CALLS
-        .entry
-
         ldil            L%dcache_stride, %r1
         ldw             R%dcache_stride(%r1), %r23
         ldo             -1(%r23), %r21
@@ -1105,16 +1017,9 @@ ENTRY_CFI(flush_kernel_dcache_range_asm)
         syncdma
         bv              %r0(%r2)
         nop
-        .exit
-
-        .procend
 ENDPROC_CFI(flush_kernel_dcache_range_asm)
 
 ENTRY_CFI(purge_kernel_dcache_range_asm)
-        .proc
-        .callinfo NO_CALLS
-        .entry
-
         ldil            L%dcache_stride, %r1
         ldw             R%dcache_stride(%r1), %r23
         ldo             -1(%r23), %r21
@@ -1127,16 +1032,9 @@ ENTRY_CFI(purge_kernel_dcache_range_asm)
         syncdma
         bv              %r0(%r2)
         nop
-        .exit
-
-        .procend
 ENDPROC_CFI(purge_kernel_dcache_range_asm)
 
 ENTRY_CFI(flush_user_icache_range_asm)
-        .proc
-        .callinfo NO_CALLS
-        .entry
-
         ldil            L%icache_stride, %r1
         ldw             R%icache_stride(%r1), %r23
         ldo             -1(%r23), %r21
@@ -1148,16 +1046,9 @@ ENTRY_CFI(flush_user_icache_range_asm)
         sync
         bv              %r0(%r2)
         nop
-        .exit
-
-        .procend
 ENDPROC_CFI(flush_user_icache_range_asm)
 
 ENTRY_CFI(flush_kernel_icache_page)
-        .proc
-        .callinfo NO_CALLS
-        .entry
-
         ldil            L%icache_stride, %r1
         ldw             R%icache_stride(%r1), %r23
 
@@ -1191,16 +1082,9 @@ ENTRY_CFI(flush_kernel_icache_page)
         sync
         bv              %r0(%r2)
         nop
-        .exit
-
-        .procend
 ENDPROC_CFI(flush_kernel_icache_page)
 
 ENTRY_CFI(flush_kernel_icache_range_asm)
-        .proc
-        .callinfo NO_CALLS
-        .entry
-
         ldil            L%icache_stride, %r1
         ldw             R%icache_stride(%r1), %r23
         ldo             -1(%r23), %r21
@@ -1212,8 +1096,6 @@ ENTRY_CFI(flush_kernel_icache_range_asm)
         sync
         bv              %r0(%r2)
         nop
-        .exit
-        .procend
 ENDPROC_CFI(flush_kernel_icache_range_asm)
 
         __INIT
@@ -1223,10 +1105,6 @@ ENDPROC_CFI(flush_kernel_icache_range_asm)
          */
         .align  256
 ENTRY_CFI(disable_sr_hashing_asm)
-        .proc
-        .callinfo NO_CALLS
-        .entry
-
         /*
          * Switch to real mode
          */
@@ -1308,9 +1186,6 @@ srdis_done:
 
 2:      bv              %r0(%r2)
         nop
-        .exit
-
-        .procend
 ENDPROC_CFI(disable_sr_hashing_asm)
 
         .end
diff --git a/arch/parisc/kernel/process.c b/arch/parisc/kernel/process.c
index b931745815e0..eb39e7e380d7 100644
--- a/arch/parisc/kernel/process.c
+++ b/arch/parisc/kernel/process.c
@@ -302,7 +302,7 @@ get_wchan(struct task_struct *p)
                 ip = info.ip;
                 if (!in_sched_functions(ip))
                         return ip;
-        } while (count++ < 16);
+        } while (count++ < MAX_UNWIND_ENTRIES);
         return 0;
 }
 
diff --git a/arch/parisc/kernel/real2.S b/arch/parisc/kernel/real2.S
index cc9963421a19..2b16d8d6598f 100644
--- a/arch/parisc/kernel/real2.S
+++ b/arch/parisc/kernel/real2.S
@@ -35,12 +35,6 @@ real32_stack:
 real64_stack:
         .block  8192
 
-#ifdef CONFIG_64BIT
-#  define REG_SZ 8
-#else
-#  define REG_SZ 4
-#endif
-
 #define N_SAVED_REGS 9
 
 save_cr_space:
diff --git a/arch/parisc/kernel/traps.c b/arch/parisc/kernel/traps.c
index 4309ad31a874..318815212518 100644
--- a/arch/parisc/kernel/traps.c
+++ b/arch/parisc/kernel/traps.c
@@ -172,7 +172,7 @@ static void do_show_stack(struct unwind_frame_info *info)
         int i = 1;
 
         printk(KERN_CRIT "Backtrace:\n");
-        while (i <= 16) {
+        while (i <= MAX_UNWIND_ENTRIES) {
                 if (unwind_once(info) < 0 || info->ip == 0)
                         break;
 
diff --git a/arch/parisc/kernel/unwind.c b/arch/parisc/kernel/unwind.c
index a4b430f440a9..5cdf13069dd9 100644
--- a/arch/parisc/kernel/unwind.c
+++ b/arch/parisc/kernel/unwind.c
@@ -13,7 +13,6 @@
 #include <linux/init.h>
 #include <linux/sched.h>
 #include <linux/slab.h>
-#include <linux/kallsyms.h>
 #include <linux/sort.h>
 
 #include <linux/uaccess.h>
@@ -117,7 +116,8 @@ unwind_table_init(struct unwind_table *table, const char *name,
         for (; start <= end; start++) {
                 if (start < end && 
                     start->region_end > (start+1)->region_start) {
-                        printk("WARNING: Out of order unwind entry! %p and %p\n", start, start+1);
+                        pr_warn("Out of order unwind entry! %px and %px\n",
+                                start, start+1);
                 }
 
                 start->region_start += base_addr;
@@ -203,25 +203,60 @@ int __init unwind_init(void)
         return 0;
 }
 
-#ifdef CONFIG_64BIT
-#define get_func_addr(fptr) fptr[2]
-#else
-#define get_func_addr(fptr) fptr[0]
-#endif
-
 static int unwind_special(struct unwind_frame_info *info, unsigned long pc, int frame_size)
 {
-        extern void handle_interruption(int, struct pt_regs *);
-        static unsigned long *hi = (unsigned long *)&handle_interruption;
-
-        if (pc == get_func_addr(hi)) {
+        /*
+         * 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
+         */
+        extern void * const handle_interruption;
+        extern void * const ret_from_kernel_thread;
+        extern void * const syscall_exit;
+        extern void * const intr_return;
+        extern void * const _switch_to_ret;
+#ifdef CONFIG_IRQSTACKS
+        extern void * const call_on_stack;
+#endif /* CONFIG_IRQSTACKS */
+
+        if (pc == (unsigned long) &handle_interruption) {
                 struct pt_regs *regs = (struct pt_regs *)(info->sp - frame_size - PT_SZ_ALGN);
                 dbg("Unwinding through handle_interruption()\n");
                 info->prev_sp = regs->gr[30];
                 info->prev_ip = regs->iaoq[0];
+                return 1;
+        }
+
+        if (pc == (unsigned long) &ret_from_kernel_thread ||
+            pc == (unsigned long) &syscall_exit) {
+                info->prev_sp = info->prev_ip = 0;
+                return 1;
+        }
+
+        if (pc == (unsigned long) &intr_return) {
+                struct pt_regs *regs;
+
+                dbg("Found intr_return()\n");
+                regs = (struct pt_regs *)(info->sp - PT_SZ_ALGN);
+                info->prev_sp = regs->gr[30];
+                info->prev_ip = regs->iaoq[0];
+                info->rp = regs->gr[2];
+                return 1;
+        }
+
+        if (pc == (unsigned long) &_switch_to_ret) {
+                info->prev_sp = info->sp - CALLEE_SAVE_FRAME_SIZE;
+                info->prev_ip = *(unsigned long *)(info->prev_sp - RP_OFFSET);
+                return 1;
+        }
 
+#ifdef CONFIG_IRQSTACKS
+        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;
         }
+#endif
 
         return 0;
 }
@@ -238,34 +273,8 @@ static void unwind_frame_regs(struct unwind_frame_info *info)
         if (e == NULL) {
                 unsigned long sp;
 
-                dbg("Cannot find unwind entry for 0x%lx; forced unwinding\n", info->ip);
-
-#ifdef CONFIG_KALLSYMS
-                /* Handle some frequent special cases.... */
-                {
-                        char symname[KSYM_NAME_LEN];
-                        char *modname;
-
-                        kallsyms_lookup(info->ip, NULL, NULL, &modname,
-                                symname);
-
-                        dbg("info->ip = 0x%lx, name = %s\n", info->ip, symname);
-
-                        if (strcmp(symname, "_switch_to_ret") == 0) {
-                                info->prev_sp = info->sp - CALLEE_SAVE_FRAME_SIZE;
-                                info->prev_ip = *(unsigned long *)(info->prev_sp - RP_OFFSET);
-                                dbg("_switch_to_ret @ %lx - setting "
-                                    "prev_sp=%lx prev_ip=%lx\n", 
-                                    info->ip, info->prev_sp, 
-                                    info->prev_ip);
-                                return;
-                        } else if (strcmp(symname, "ret_from_kernel_thread") == 0 ||
-                                   strcmp(symname, "syscall_exit") == 0) {
-                                info->prev_ip = info->prev_sp = 0;
-                                return;
-                        }
-                }
-#endif
+                dbg("Cannot find unwind entry for %pS; forced unwinding\n",
+                        (void *) info->ip);
 
                 /* Since we are doing the unwinding blind, we don't know if
                    we are adjusting the stack correctly or extracting the rp
diff --git a/arch/parisc/lib/lusercopy.S b/arch/parisc/lib/lusercopy.S
index d4fe19806d57..b53fb6fedf06 100644
--- a/arch/parisc/lib/lusercopy.S
+++ b/arch/parisc/lib/lusercopy.S
@@ -64,9 +64,6 @@
          */
 
 ENTRY_CFI(lclear_user)
-        .proc
-        .callinfo NO_CALLS
-        .entry
         comib,=,n   0,%r25,$lclu_done
         get_sr
 $lclu_loop:
@@ -81,13 +78,9 @@ $lclu_done:
         ldo         1(%r25),%r25
 
         ASM_EXCEPTIONTABLE_ENTRY(1b,2b)
-
-        .exit
 ENDPROC_CFI(lclear_user)
 
 
-        .procend
-
         /*
          * long lstrnlen_user(char *s, long n)
          *
@@ -97,9 +90,6 @@ ENDPROC_CFI(lclear_user)
          */
 
 ENTRY_CFI(lstrnlen_user)
-        .proc
-        .callinfo NO_CALLS
-        .entry
         comib,=     0,%r25,$lslen_nzero
         copy        %r26,%r24
         get_sr
@@ -111,7 +101,6 @@ $lslen_loop:
 $lslen_done:
         bv          %r0(%r2)
         sub         %r26,%r24,%r28
-        .exit
 
 $lslen_nzero:
         b           $lslen_done
@@ -125,9 +114,6 @@ $lslen_nzero:
 
 ENDPROC_CFI(lstrnlen_user)
 
-        .procend
-
-
 
 /*
  * unsigned long pa_memcpy(void *dstp, const void *srcp, unsigned long len)
@@ -186,10 +172,6 @@ ENDPROC_CFI(lstrnlen_user)
         save_len = r31
 
 ENTRY_CFI(pa_memcpy)
-        .proc
-        .callinfo NO_CALLS
-        .entry
-
         /* Last destination address */
         add     dst,len,end
 
@@ -439,9 +421,6 @@ ENTRY_CFI(pa_memcpy)
         b       .Lcopy_done
 10:     stw,ma  t1,4(dstspc,dst)
         ASM_EXCEPTIONTABLE_ENTRY(10b,.Lcopy_done)
-
-        .exit
 ENDPROC_CFI(pa_memcpy)
-        .procend
 
         .end