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runtime: save some stack space for racecall on ARM64

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To avoid nosplit overflow in -race -N -l build.

For #51247.

Change-Id: I48426bbd4adefd18eaf26ed51b4113c6a28305b8
Reviewed-on: https://go-review.googlesource.com/c/go/+/386716
Trust: Cherry Mui <cherryyz@google.com>
Run-TryBot: Cherry Mui <cherryyz@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Michael Knyszek <mknyszek@google.com>
This commit is contained in:
Cherry Mui 2022-02-17 19:45:50 -05:00
parent d93cc8cb96
commit d27248c52f
1 changed files with 6 additions and 4 deletions
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10
src/runtime/race_arm64.s
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@ -396,12 +396,12 @@ racecallatomic_ignore:
// Addr is outside the good range.
// Call __tsan_go_ignore_sync_begin to ignore synchronization during the atomic op.
// An attempt to synchronize on the address would cause crash.
MOVD R9, R20 // remember the original function
MOVD R9, R21 // remember the original function
MOVD $__tsan_go_ignore_sync_begin(SB), R9
load_g
MOVD g_racectx(g), R0 // goroutine context
BL racecall<>(SB)
MOVD R20, R9 // restore the original function
MOVD R21, R9 // restore the original function
// Call the atomic function.
// racecall will call LLVM race code which might clobber R28 (g)
load_g
@ -428,10 +428,12 @@ TEXT runtime·racecall(SB), NOSPLIT, $0-0
JMP racecall<>(SB)
// Switches SP to g0 stack and calls (R9). Arguments already set.
TEXT racecall<>(SB), NOSPLIT, $0-0
// Clobbers R19, R20.
TEXT racecall<>(SB), NOSPLIT|NOFRAME, $0-0
MOVD g_m(g), R10
// Switch to g0 stack.
MOVD RSP, R19 // callee-saved, preserved across the CALL
MOVD R30, R20 // callee-saved, preserved across the CALL
MOVD m_g0(R10), R11
CMP R11, g
BEQ call // already on g0
@ -440,7 +442,7 @@ TEXT racecall<>(SB), NOSPLIT, $0-0
call:
BL R9
MOVD R19, RSP
RET
JMP (R20)
// C->Go callback thunk that allows to call runtime·racesymbolize from C code.
// Direct Go->C race call has only switched SP, finish g->g0 switch by setting correct g.