[PATCH 6/7] alpha: Generate dwarf2 unwind info for various kernel entry points.

From: Richard Henderson
Date: Tue Jul 16 2013 - 13:06:12 EST


Having unwind info past the PALcode generated stack frame makes
debugging the kernel significantly easier.

Signed-off-by: Richard Henderson <rth@xxxxxxxxxxx>
---
arch/alpha/kernel/entry.S | 399 +++++++++++++++++++++++++++++++++-------------
1 file changed, 288 insertions(+), 111 deletions(-)

diff --git a/arch/alpha/kernel/entry.S b/arch/alpha/kernel/entry.S
index f62a994..a969b95 100644
--- a/arch/alpha/kernel/entry.S
+++ b/arch/alpha/kernel/entry.S
@@ -12,11 +12,32 @@

.text
.set noat
+ .cfi_sections .debug_frame

/* Stack offsets. */
#define SP_OFF 184
#define SWITCH_STACK_SIZE 320

+.macro CFI_START_OSF_FRAME func
+ .align 4
+ .globl \func
+ .type \func,@function
+\func:
+ .cfi_startproc simple
+ .cfi_return_column 64
+ .cfi_def_cfa $sp, 48
+ .cfi_rel_offset 64, 8
+ .cfi_rel_offset $gp, 16
+ .cfi_rel_offset $16, 24
+ .cfi_rel_offset $17, 32
+ .cfi_rel_offset $18, 40
+.endm
+
+.macro CFI_END_OSF_FRAME func
+ .cfi_endproc
+ .size \func, . - \func
+.endm
+
/*
* This defines the normal kernel pt-regs layout.
*
@@ -27,100 +48,158 @@
* the palcode-provided values are available to the signal handler.
*/

-#define SAVE_ALL \
- subq $sp, SP_OFF, $sp; \
- stq $0, 0($sp); \
- stq $1, 8($sp); \
- stq $2, 16($sp); \
- stq $3, 24($sp); \
- stq $4, 32($sp); \
- stq $28, 144($sp); \
- lda $2, alpha_mv; \
- stq $5, 40($sp); \
- stq $6, 48($sp); \
- stq $7, 56($sp); \
- stq $8, 64($sp); \
- stq $19, 72($sp); \
- stq $20, 80($sp); \
- stq $21, 88($sp); \
- ldq $2, HAE_CACHE($2); \
- stq $22, 96($sp); \
- stq $23, 104($sp); \
- stq $24, 112($sp); \
- stq $25, 120($sp); \
- stq $26, 128($sp); \
- stq $27, 136($sp); \
- stq $2, 152($sp); \
- stq $16, 160($sp); \
- stq $17, 168($sp); \
+.macro SAVE_ALL
+ subq $sp, SP_OFF, $sp
+ .cfi_adjust_cfa_offset SP_OFF
+ stq $0, 0($sp)
+ stq $1, 8($sp)
+ stq $2, 16($sp)
+ stq $3, 24($sp)
+ stq $4, 32($sp)
+ stq $28, 144($sp)
+ .cfi_rel_offset $0, 0
+ .cfi_rel_offset $1, 8
+ .cfi_rel_offset $2, 16
+ .cfi_rel_offset $3, 24
+ .cfi_rel_offset $4, 32
+ .cfi_rel_offset $28, 144
+ lda $2, alpha_mv
+ stq $5, 40($sp)
+ stq $6, 48($sp)
+ stq $7, 56($sp)
+ stq $8, 64($sp)
+ stq $19, 72($sp)
+ stq $20, 80($sp)
+ stq $21, 88($sp)
+ ldq $2, HAE_CACHE($2)
+ stq $22, 96($sp)
+ stq $23, 104($sp)
+ stq $24, 112($sp)
+ stq $25, 120($sp)
+ stq $26, 128($sp)
+ stq $27, 136($sp)
+ stq $2, 152($sp)
+ stq $16, 160($sp)
+ stq $17, 168($sp)
stq $18, 176($sp)
+ .cfi_rel_offset $5, 40
+ .cfi_rel_offset $6, 48
+ .cfi_rel_offset $7, 56
+ .cfi_rel_offset $8, 64
+ .cfi_rel_offset $19, 72
+ .cfi_rel_offset $20, 80
+ .cfi_rel_offset $21, 88
+ .cfi_rel_offset $22, 96
+ .cfi_rel_offset $23, 104
+ .cfi_rel_offset $24, 112
+ .cfi_rel_offset $25, 120
+ .cfi_rel_offset $26, 128
+ .cfi_rel_offset $27, 136
+.endm

-#define RESTORE_ALL \
- lda $19, alpha_mv; \
- ldq $0, 0($sp); \
- ldq $1, 8($sp); \
- ldq $2, 16($sp); \
- ldq $3, 24($sp); \
- ldq $21, 152($sp); \
- ldq $20, HAE_CACHE($19); \
- ldq $4, 32($sp); \
- ldq $5, 40($sp); \
- ldq $6, 48($sp); \
- ldq $7, 56($sp); \
- subq $20, $21, $20; \
- ldq $8, 64($sp); \
- beq $20, 99f; \
- ldq $20, HAE_REG($19); \
- stq $21, HAE_CACHE($19); \
- stq $21, 0($20); \
-99:; \
- ldq $19, 72($sp); \
- ldq $20, 80($sp); \
- ldq $21, 88($sp); \
- ldq $22, 96($sp); \
- ldq $23, 104($sp); \
- ldq $24, 112($sp); \
- ldq $25, 120($sp); \
- ldq $26, 128($sp); \
- ldq $27, 136($sp); \
- ldq $28, 144($sp); \
+.macro RESTORE_ALL
+ lda $19, alpha_mv
+ ldq $0, 0($sp)
+ ldq $1, 8($sp)
+ ldq $2, 16($sp)
+ ldq $3, 24($sp)
+ ldq $21, 152($sp)
+ ldq $20, HAE_CACHE($19)
+ ldq $4, 32($sp)
+ ldq $5, 40($sp)
+ ldq $6, 48($sp)
+ ldq $7, 56($sp)
+ subq $20, $21, $20
+ ldq $8, 64($sp)
+ beq $20, 99f
+ ldq $20, HAE_REG($19)
+ stq $21, HAE_CACHE($19)
+ stq $21, 0($20)
+99: ldq $19, 72($sp)
+ ldq $20, 80($sp)
+ ldq $21, 88($sp)
+ ldq $22, 96($sp)
+ ldq $23, 104($sp)
+ ldq $24, 112($sp)
+ ldq $25, 120($sp)
+ ldq $26, 128($sp)
+ ldq $27, 136($sp)
+ ldq $28, 144($sp)
addq $sp, SP_OFF, $sp
+ .cfi_restore $0
+ .cfi_restore $1
+ .cfi_restore $2
+ .cfi_restore $3
+ .cfi_restore $4
+ .cfi_restore $5
+ .cfi_restore $6
+ .cfi_restore $7
+ .cfi_restore $8
+ .cfi_restore $19
+ .cfi_restore $20
+ .cfi_restore $21
+ .cfi_restore $22
+ .cfi_restore $23
+ .cfi_restore $24
+ .cfi_restore $25
+ .cfi_restore $26
+ .cfi_restore $27
+ .cfi_restore $28
+ .cfi_adjust_cfa_offset -SP_OFF
+.endm
+
+.macro DO_SWITCH_STACK
+ bsr $1, do_switch_stack
+ .cfi_adjust_cfa_offset SWITCH_STACK_SIZE
+ .cfi_rel_offset $9, 0
+ .cfi_rel_offset $10, 8
+ .cfi_rel_offset $11, 16
+ .cfi_rel_offset $12, 24
+ .cfi_rel_offset $13, 32
+ .cfi_rel_offset $14, 40
+ .cfi_rel_offset $15, 48
+ /* We don't really care about the FP registers for debugging. */
+.endm
+
+.macro UNDO_SWITCH_STACK
+ bsr $1, undo_switch_stack
+ .cfi_restore $9
+ .cfi_restore $10
+ .cfi_restore $11
+ .cfi_restore $12
+ .cfi_restore $13
+ .cfi_restore $14
+ .cfi_restore $15
+ .cfi_adjust_cfa_offset -SWITCH_STACK_SIZE
+.endm

/*
* Non-syscall kernel entry points.
*/

- .align 4
- .globl entInt
- .ent entInt
-entInt:
+CFI_START_OSF_FRAME entInt
SAVE_ALL
lda $8, 0x3fff
lda $26, ret_from_sys_call
bic $sp, $8, $8
mov $sp, $19
jsr $31, do_entInt
-.end entInt
+CFI_END_OSF_FRAME entInt

- .align 4
- .globl entArith
- .ent entArith
-entArith:
+CFI_START_OSF_FRAME entArith
SAVE_ALL
lda $8, 0x3fff
lda $26, ret_from_sys_call
bic $sp, $8, $8
mov $sp, $18
jsr $31, do_entArith
-.end entArith
+CFI_END_OSF_FRAME entArith

- .align 4
- .globl entMM
- .ent entMM
-entMM:
+CFI_START_OSF_FRAME entMM
SAVE_ALL
/* save $9 - $15 so the inline exception code can manipulate them. */
subq $sp, 56, $sp
+ .cfi_adjust_cfa_offset 56
stq $9, 0($sp)
stq $10, 8($sp)
stq $11, 16($sp)
@@ -128,6 +207,13 @@ entMM:
stq $13, 32($sp)
stq $14, 40($sp)
stq $15, 48($sp)
+ .cfi_rel_offset $9, 0
+ .cfi_rel_offset $10, 8
+ .cfi_rel_offset $11, 16
+ .cfi_rel_offset $12, 24
+ .cfi_rel_offset $13, 32
+ .cfi_rel_offset $14, 40
+ .cfi_rel_offset $15, 48
addq $sp, 56, $19
/* handle the fault */
lda $8, 0x3fff
@@ -142,28 +228,33 @@ entMM:
ldq $14, 40($sp)
ldq $15, 48($sp)
addq $sp, 56, $sp
+ .cfi_restore $9
+ .cfi_restore $10
+ .cfi_restore $11
+ .cfi_restore $12
+ .cfi_restore $13
+ .cfi_restore $14
+ .cfi_restore $15
+ .cfi_adjust_cfa_offset -56
/* finish up the syscall as normal. */
br ret_from_sys_call
-.end entMM
+CFI_END_OSF_FRAME entMM

- .align 4
- .globl entIF
- .ent entIF
-entIF:
+CFI_START_OSF_FRAME entIF
SAVE_ALL
lda $8, 0x3fff
lda $26, ret_from_sys_call
bic $sp, $8, $8
mov $sp, $17
jsr $31, do_entIF
-.end entIF
+CFI_END_OSF_FRAME entIF

- .align 4
- .globl entUna
- .ent entUna
-entUna:
+CFI_START_OSF_FRAME entUna
lda $sp, -256($sp)
+ .cfi_adjust_cfa_offset 256
stq $0, 0($sp)
+ .cfi_rel_offset $0, 0
+ .cfi_remember_state
ldq $0, 256($sp) /* get PS */
stq $1, 8($sp)
stq $2, 16($sp)
@@ -195,6 +286,32 @@ entUna:
stq $28, 224($sp)
mov $sp, $19
stq $gp, 232($sp)
+ .cfi_rel_offset $1, 1*8
+ .cfi_rel_offset $2, 2*8
+ .cfi_rel_offset $3, 3*8
+ .cfi_rel_offset $4, 4*8
+ .cfi_rel_offset $5, 5*8
+ .cfi_rel_offset $6, 6*8
+ .cfi_rel_offset $7, 7*8
+ .cfi_rel_offset $8, 8*8
+ .cfi_rel_offset $9, 9*8
+ .cfi_rel_offset $10, 10*8
+ .cfi_rel_offset $11, 11*8
+ .cfi_rel_offset $12, 12*8
+ .cfi_rel_offset $13, 13*8
+ .cfi_rel_offset $14, 14*8
+ .cfi_rel_offset $15, 15*8
+ .cfi_rel_offset $19, 19*8
+ .cfi_rel_offset $20, 20*8
+ .cfi_rel_offset $21, 21*8
+ .cfi_rel_offset $22, 22*8
+ .cfi_rel_offset $23, 23*8
+ .cfi_rel_offset $24, 24*8
+ .cfi_rel_offset $25, 25*8
+ .cfi_rel_offset $26, 26*8
+ .cfi_rel_offset $27, 27*8
+ .cfi_rel_offset $28, 28*8
+ .cfi_rel_offset $29, 29*8
lda $8, 0x3fff
stq $31, 248($sp)
bic $sp, $8, $8
@@ -228,16 +345,45 @@ entUna:
ldq $28, 224($sp)
ldq $gp, 232($sp)
lda $sp, 256($sp)
+ .cfi_restore $1
+ .cfi_restore $2
+ .cfi_restore $3
+ .cfi_restore $4
+ .cfi_restore $5
+ .cfi_restore $6
+ .cfi_restore $7
+ .cfi_restore $8
+ .cfi_restore $9
+ .cfi_restore $10
+ .cfi_restore $11
+ .cfi_restore $12
+ .cfi_restore $13
+ .cfi_restore $14
+ .cfi_restore $15
+ .cfi_restore $19
+ .cfi_restore $20
+ .cfi_restore $21
+ .cfi_restore $22
+ .cfi_restore $23
+ .cfi_restore $24
+ .cfi_restore $25
+ .cfi_restore $26
+ .cfi_restore $27
+ .cfi_restore $28
+ .cfi_restore $29
+ .cfi_adjust_cfa_offset -256
call_pal PAL_rti
-.end entUna

.align 4
- .ent entUnaUser
entUnaUser:
+ .cfi_restore_state
ldq $0, 0($sp) /* restore original $0 */
lda $sp, 256($sp) /* pop entUna's stack frame */
+ .cfi_restore $0
+ .cfi_adjust_cfa_offset -256
SAVE_ALL /* setup normal kernel stack */
lda $sp, -56($sp)
+ .cfi_adjust_cfa_offset 56
stq $9, 0($sp)
stq $10, 8($sp)
stq $11, 16($sp)
@@ -245,6 +391,13 @@ entUnaUser:
stq $13, 32($sp)
stq $14, 40($sp)
stq $15, 48($sp)
+ .cfi_rel_offset $9, 0
+ .cfi_rel_offset $10, 8
+ .cfi_rel_offset $11, 16
+ .cfi_rel_offset $12, 24
+ .cfi_rel_offset $13, 32
+ .cfi_rel_offset $14, 40
+ .cfi_rel_offset $15, 48
lda $8, 0x3fff
addq $sp, 56, $19
bic $sp, $8, $8
@@ -257,20 +410,25 @@ entUnaUser:
ldq $14, 40($sp)
ldq $15, 48($sp)
lda $sp, 56($sp)
+ .cfi_restore $9
+ .cfi_restore $10
+ .cfi_restore $11
+ .cfi_restore $12
+ .cfi_restore $13
+ .cfi_restore $14
+ .cfi_restore $15
+ .cfi_adjust_cfa_offset -56
br ret_from_sys_call
-.end entUnaUser
+CFI_END_OSF_FRAME entUna

- .align 4
- .globl entDbg
- .ent entDbg
-entDbg:
+CFI_START_OSF_FRAME entDbg
SAVE_ALL
lda $8, 0x3fff
lda $26, ret_from_sys_call
bic $sp, $8, $8
mov $sp, $16
jsr $31, do_entDbg
-.end entDbg
+CFI_END_OSF_FRAME entDbg

/*
* The system call entry point is special. Most importantly, it looks
@@ -285,8 +443,12 @@ entDbg:

.align 4
.globl entSys
- .globl ret_from_sys_call
- .ent entSys
+ .type entSys, @function
+ .cfi_startproc simple
+ .cfi_return_column 64
+ .cfi_def_cfa $sp, 48
+ .cfi_rel_offset 64, 8
+ .cfi_rel_offset $gp, 16
entSys:
SAVE_ALL
lda $8, 0x3fff
@@ -300,6 +462,9 @@ entSys:
stq $17, SP_OFF+32($sp)
s8addq $0, $5, $5
stq $18, SP_OFF+40($sp)
+ .cfi_rel_offset $16, SP_OFF+24
+ .cfi_rel_offset $17, SP_OFF+32
+ .cfi_rel_offset $18, SP_OFF+40
blbs $3, strace
beq $4, 1f
ldq $27, 0($5)
@@ -310,6 +475,7 @@ entSys:
stq $31, 72($sp) /* a3=0 => no error */

.align 4
+ .globl ret_from_sys_call
ret_from_sys_call:
cmovne $26, 0, $18 /* $18 = 0 => non-restartable */
ldq $0, SP_OFF($sp)
@@ -324,10 +490,12 @@ ret_to_user:
and $17, _TIF_WORK_MASK, $2
bne $2, work_pending
restore_all:
+ .cfi_remember_state
RESTORE_ALL
call_pal PAL_rti

ret_to_kernel:
+ .cfi_restore_state
lda $16, 7
call_pal PAL_swpipl
br restore_all
@@ -356,7 +524,6 @@ $ret_success:
stq $0, 0($sp)
stq $31, 72($sp) /* a3=0 => no error */
br ret_from_sys_call
-.end entSys

/*
* Do all cleanup when returning from all interrupts and system calls.
@@ -370,7 +537,7 @@ $ret_success:
*/

.align 4
- .ent work_pending
+ .type work_pending, @function
work_pending:
and $17, _TIF_NOTIFY_RESUME | _TIF_SIGPENDING, $2
bne $2, $work_notifysig
@@ -387,23 +554,22 @@ $work_resched:

$work_notifysig:
mov $sp, $16
- bsr $1, do_switch_stack
+ DO_SWITCH_STACK
jsr $26, do_work_pending
- bsr $1, undo_switch_stack
+ UNDO_SWITCH_STACK
br restore_all
-.end work_pending

/*
* PTRACE syscall handler
*/

.align 4
- .ent strace
+ .type strace, @function
strace:
/* set up signal stack, call syscall_trace */
- bsr $1, do_switch_stack
+ DO_SWITCH_STACK
jsr $26, syscall_trace_enter /* returns the syscall number */
- bsr $1, undo_switch_stack
+ UNDO_SWITCH_STACK

/* get the arguments back.. */
ldq $16, SP_OFF+24($sp)
@@ -431,9 +597,9 @@ ret_from_straced:
$strace_success:
stq $0, 0($sp) /* save return value */

- bsr $1, do_switch_stack
+ DO_SWITCH_STACK
jsr $26, syscall_trace_leave
- bsr $1, undo_switch_stack
+ UNDO_SWITCH_STACK
br $31, ret_from_sys_call

.align 3
@@ -447,26 +613,31 @@ $strace_error:
stq $0, 0($sp)
stq $1, 72($sp) /* a3 for return */

- bsr $1, do_switch_stack
+ DO_SWITCH_STACK
mov $18, $9 /* save old syscall number */
mov $19, $10 /* save old a3 */
jsr $26, syscall_trace_leave
mov $9, $18
mov $10, $19
- bsr $1, undo_switch_stack
+ UNDO_SWITCH_STACK

mov $31, $26 /* tell "ret_from_sys_call" we can restart */
br ret_from_sys_call
-.end strace
+CFI_END_OSF_FRAME entSys

/*
* Save and restore the switch stack -- aka the balance of the user context.
*/

.align 4
- .ent do_switch_stack
+ .type do_switch_stack, @function
+ .cfi_startproc simple
+ .cfi_return_column 64
+ .cfi_def_cfa $sp, 0
+ .cfi_register 64, $1
do_switch_stack:
lda $sp, -SWITCH_STACK_SIZE($sp)
+ .cfi_adjust_cfa_offset SWITCH_STACK_SIZE
stq $9, 0($sp)
stq $10, 8($sp)
stq $11, 16($sp)
@@ -510,10 +681,14 @@ do_switch_stack:
stt $f0, 312($sp) # save fpcr in slot of $f31
ldt $f0, 64($sp) # dont let "do_switch_stack" change fp state.
ret $31, ($1), 1
-.end do_switch_stack
+ .cfi_endproc
+ .size do_switch_stack, .-do_switch_stack

.align 4
- .ent undo_switch_stack
+ .type undo_switch_stack, @function
+ .cfi_startproc simple
+ .cfi_def_cfa $sp, 0
+ .cfi_register 64, $1
undo_switch_stack:
ldq $9, 0($sp)
ldq $10, 8($sp)
@@ -558,7 +733,8 @@ undo_switch_stack:
ldt $f30, 304($sp)
lda $sp, SWITCH_STACK_SIZE($sp)
ret $31, ($1), 1
-.end undo_switch_stack
+ .cfi_endproc
+ .size undo_switch_stack, .-undo_switch_stack

/*
* The meat of the context switch code.
@@ -566,17 +742,18 @@ undo_switch_stack:

.align 4
.globl alpha_switch_to
- .ent alpha_switch_to
+ .type alpha_switch_to, @function
+ .cfi_startproc
alpha_switch_to:
- .prologue 0
- bsr $1, do_switch_stack
+ DO_SWITCH_STACK
call_pal PAL_swpctx
lda $8, 0x3fff
- bsr $1, undo_switch_stack
+ UNDO_SWITCH_STACK
bic $sp, $8, $8
mov $17, $0
ret
-.end alpha_switch_to
+ .cfi_endproc
+ .size alpha_switch_to, .-alpha_switch_to

/*
* New processes begin life here.
--
1.8.1.4

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