Stowage/go
2
0
Fork 0
mirror of https://github.com/golang/go.git synced 2026-02-07 02:09:55 +00:00
Code Issues Projects Releases Packages Wiki Activity

runtime: align end of systemstack_switch prologue on amd64 for consistency with gosave_systemstack_switch

Browse source 
gosave_systemstack_switch saves PC with fixed offset of 8 bytes from systemstack_switch to bypass prologue.
This commit makes this offset consistent with actual address of UNDEF instruction intended to be at that address.

Fixes #71440

Change-Id: Ibe6458c5bcb0bdaec228a2f13d6aec7ecc0e319e
Reviewed-on: https://go-review.googlesource.com/c/go/+/740360
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Auto-Submit: Keith Randall <khr@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
Reviewed-by: Keith Randall <khr@google.com>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
This commit is contained in:
Vasily Leonenko 2026-01-29 21:12:49 +03:00 • committed by Gopher Robot
parent 35c5deb1d4
commit f14d8975a2
1 changed files with 5 additions and 2 deletions
Download patch file Download diff file Expand all files Collapse all files

7
src/runtime/asm_amd64.s
View file

@ -510,6 +510,8 @@ goodm:
// The frame layout needs to match systemstack
// so that it can pretend to be systemstack_switch.
TEXT runtime·systemstack_switch(SB), NOSPLIT, $0-0
// Align for consistency with offset used in gosave_systemstack_switch
PCALIGN $8
UNDEF
// Make sure this function is not leaf,
// so the frame is saved.
@ -885,8 +887,9 @@ TEXT ·publicationBarrier<ABIInternal>(SB),NOSPLIT,$0-0
// Smashes R9.
TEXT gosave_systemstack_switch<>(SB),NOSPLIT|NOFRAME,$0
// Take systemstack_switch PC and add 8 bytes to skip
// the prologue. The final location does not matter
// as long as we are between the prologue and the epilogue.
// the prologue. Keep 8 bytes offset consistent with
// PCALIGN $8 in systemstack_swtich, pointing start of
// UNDEF instruction beyond prologue.
MOVQ $runtime·systemstack_switch+8(SB), R9
MOVQ R9, (g_sched+gobuf_pc)(R14)
LEAQ 8(SP), R9