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Commit c8921d72 authored by Helge Deller's avatar Helge Deller
Browse files

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: default avatarHelge Deller <deller@gmx.de>
parent 3b885ac1

arch/parisc/include/asm/assembly.h

+2 −0
Original line number Diff line number Diff line
@@ -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

arch/parisc/include/asm/linkage.h

+11 −6
Original line number Diff line number Diff line
@@ -18,9 +18,9 @@ 
#ifdef __ASSEMBLY__



#define ENTRY(name) \

	.export name !\

	ALIGN	!\

name:

name:		ASM_NL\

	.export name



#ifdef CONFIG_64BIT

#define ENDPROC(name) \
@@ -31,13 +31,18 @@ 
	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__ */

arch/parisc/include/asm/unwind.h

+3 −0
Original line number Diff line number Diff line
@@ -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;

arch/parisc/kernel/entry.S

+21 −32
Original line number Diff line number Diff line
@@ -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 */

arch/parisc/kernel/pacache.S

+0 −125
Original line number Diff line number Diff line
@@ -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