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authorHelge Deller <deller@gmx.de>2018-08-05 00:03:29 +0200
committerHelge Deller <deller@gmx.de>2018-08-13 09:54:17 +0200
commitc8921d72e390cb6fca3fb2b0c2badfda851647eb (patch)
tree8c6aec1a9405da9caad70088a7dfd910b71b6675 /arch/parisc/kernel
parent3b885ac1dc35b87a39ee176a6c7e2af9c789d8b8 (diff)
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>
Diffstat (limited to 'arch/parisc/kernel')
-rw-r--r--arch/parisc/kernel/entry.S53
-rw-r--r--arch/parisc/kernel/pacache.S125
-rw-r--r--arch/parisc/kernel/process.c2
-rw-r--r--arch/parisc/kernel/real2.S6
-rw-r--r--arch/parisc/kernel/traps.c2
-rw-r--r--arch/parisc/kernel/unwind.c89
6 files changed, 72 insertions, 205 deletions
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