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[RS6000] libgcc cfi 

There are a few places in libgcc assembly where we don't emit call
frame information for functions, potentially breaking unwinding from
asynchronous signal handlers.  This patch fixes them.  Although I
patch tramp.S there is no attempt made to provide CFI for the actual
trampoline on the stack.  Doing that would require generating CFI at
run time and both registering and deregistering it, which is probably
not worth doing since it would significantly slow down the call.

	* config/rs6000/morestack.S (__stack_split_initialize),
	(__morestack_get_guard, __morestack_set_guard),
	(__morestack_make_guard): Provide CFI covering these functions.
	* config/rs6000/tramp.S (__trampoline_setup): Likewise.

From-SVN: r266503
This commit is contained in:
Alan Modra 2018-11-27 12:29:56 +10:30
parent 28a095763f
commit 1ea7ea181d
3 changed files with 19 additions and 3 deletions
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13
libgcc/ChangeLog
View File

@ -1,6 +1,13 @@
2018-11-27 Alan Modra <amodra@gmail.com>
* config/rs6000/morestack.S (__stack_split_initialize),
(__morestack_get_guard, __morestack_set_guard),
(__morestack_make_guard): Provide CFI covering these functions.
* config/rs6000/tramp.S (__trampoline_setup): Likewise.
2018-11-15 Xianmiao Qu <xianmiao_qu@c-sky.com>
* config/csky/linux-unwind.h (sc_pt_regs): Update for kernel.
* config/csky/linux-unwind.h (sc_pt_regs): Update for kernel.
(sc_pt_regs_lr): Update for kernel.
(sc_pt_regs_tls): Update for kernel.
@ -11,7 +18,7 @@
2018-11-13 Xianmiao Qu <xianmiao_qu@c-sky.com>
* config/csky/linux-unwind.h (_sig_ucontext_t): Remove.
(csky_fallback_frame_state): Modify the check of the
(csky_fallback_frame_state): Modify the check of the
instructions to adapt to changes in the kernel
2018-11-09 Stafford Horne <shorne@gmail.com>
@ -243,7 +250,7 @@
2018-08-22 Iain Sandoe <iain@sandoe.co.uk>
* config/unwind-dw2-fde-darwin.c
* config/unwind-dw2-fde-darwin.c
(_darwin10_Unwind_FindEnclosingFunction): move from here ...
* config/darwin10-unwind-find-enc-func.c: … to here.
* config/t-darwin: Build Darwin10 unwinder shim crt.

4
libgcc/config/rs6000/morestack.S
View File

@ -304,12 +304,15 @@ DW.ref.__gcc_personality_v0:
# new thread starts. This is called from a constructor.
# void __stack_split_initialize (void)
ENTRY(__stack_split_initialize)
.cfi_startproc
addi %r3,%r1,-0x4000 # We should have at least 16K.
std %r3,-0x7000-64(%r13) # tcbhead_t.__private_ss
# void __generic_morestack_set_initial_sp (void *sp, size_t len)
mr %r3,%r1
li %r4, 0x4000
b __generic_morestack_set_initial_sp
# The lack of .cfi_endproc here is deliberate. This function and the
# following ones can all use the default FDE.
SIZE (__stack_split_initialize)
@ -335,6 +338,7 @@ ENTRY0(__morestack_make_guard)
sub %r3,%r3,%r4
addi %r3,%r3,BACKOFF
blr
.cfi_endproc
SIZE (__morestack_make_guard)

5
libgcc/config/rs6000/tramp.S
View File

@ -56,8 +56,10 @@ trampoline_size = .-trampoline_initial
/* R6 = static chain */
FUNC_START(__trampoline_setup)
.cfi_startproc
mflr r0 /* save return address */
bcl 20,31,.LCF0 /* load up __trampoline_initial into r7 */
.cfi_register lr,r0
.LCF0:
mflr r11
addi r7,r11,trampoline_initial-4-.LCF0 /* trampoline address -4 */
@ -112,6 +114,7 @@ FUNC_START(__trampoline_setup)
addi r30,r30,_GLOBAL_OFFSET_TABLE_-1b@l
#endif
bl JUMP_TARGET(abort)
.cfi_endproc
FUNC_END(__trampoline_setup)
#endif
@ -144,6 +147,7 @@ trampoline_size = .-trampoline_initial
.popsection
FUNC_START(__trampoline_setup)
.cfi_startproc
addis 7,2,.LC0@toc@ha
ld 7,.LC0@toc@l(7) /* trampoline address -8 */
@ -180,6 +184,7 @@ FUNC_START(__trampoline_setup)
.Labort:
bl JUMP_TARGET(abort)
nop
.cfi_endproc
FUNC_END(__trampoline_setup)
#endif