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runtime: make nanotime1 reentrant

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Currently, nanotime1 (and walltime1) is not reentrant, in that it
sets m.vdsoSP at entry and clears it at exit. If a signal lands
in between, and nanotime1 is called from the signal handler, it
will clear m.vdsoSP while we are still in nanotime1. If (in the
unlikely event) it is signaled again, m.vdsoSP will be wrong,
which may cause the stack unwinding code to crash.

This CL makes it reentrant, by saving/restoring the previous
vdsoPC and vdsoSP, instead of setting it to 0 at exit.

TODO: have some way to test?

Change-Id: I9ee53b251f1d8a5a489c71d4b4c0df1dee70c3e5
Reviewed-on: https://go-review.googlesource.com/c/go/+/246763
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
This commit is contained in:
Cherry Zhang 2020-08-04 20:25:10 -04:00
parent ba9e108899
commit a93a4c1780
6 changed files with 206 additions and 36 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

38
src/runtime/sys_linux_386.s
View File

@ -222,7 +222,7 @@ TEXT runtime·mincore(SB),NOSPLIT,$0-16
RET
// func walltime1() (sec int64, nsec int32)
TEXT runtime·walltime1(SB), NOSPLIT, $0-12
TEXT runtime·walltime1(SB), NOSPLIT, $8-12
// We don't know how much stack space the VDSO code will need,
// so switch to g0.
@ -233,6 +233,13 @@ TEXT runtime·walltime1(SB), NOSPLIT, $0-12
MOVL g_m(AX), SI // SI unchanged by C code.
// Set vdsoPC and vdsoSP for SIGPROF traceback.
// Save the old values on stack and restore them on exit,
// so this function is reentrant.
MOVL m_vdsoPC(SI), CX
MOVL m_vdsoSP(SI), DX
MOVL CX, 0(SP)
MOVL DX, 4(SP)
LEAL sec+0(FP), DX
MOVL -4(DX), CX
MOVL CX, m_vdsoPC(SI)
@ -276,7 +283,15 @@ finish:
MOVL 12(SP), BX // nsec
MOVL BP, SP // Restore real SP
MOVL $0, m_vdsoSP(SI)
// Restore vdsoPC, vdsoSP
// We don't worry about being signaled between the two stores.
// If we are not in a signal handler, we'll restore vdsoSP to 0,
// and no one will care about vdsoPC. If we are in a signal handler,
// we cannot receive another signal.
MOVL 4(SP), CX
MOVL CX, m_vdsoSP(SI)
MOVL 0(SP), CX
MOVL CX, m_vdsoPC(SI)
// sec is in AX, nsec in BX
MOVL AX, sec_lo+0(FP)
@ -286,7 +301,7 @@ finish:
// int64 nanotime(void) so really
// void nanotime(int64 *nsec)
TEXT runtime·nanotime1(SB), NOSPLIT, $0-8
TEXT runtime·nanotime1(SB), NOSPLIT, $8-8
// Switch to g0 stack. See comment above in runtime·walltime.
MOVL SP, BP // Save old SP; BP unchanged by C code.
@ -296,6 +311,13 @@ TEXT runtime·nanotime1(SB), NOSPLIT, $0-8
MOVL g_m(AX), SI // SI unchanged by C code.
// Set vdsoPC and vdsoSP for SIGPROF traceback.
// Save the old values on stack and restore them on exit,
// so this function is reentrant.
MOVL m_vdsoPC(SI), CX
MOVL m_vdsoSP(SI), DX
MOVL CX, 0(SP)
MOVL DX, 4(SP)
LEAL ret+0(FP), DX
MOVL -4(DX), CX
MOVL CX, m_vdsoPC(SI)
@ -332,7 +354,15 @@ finish:
MOVL 12(SP), BX // nsec
MOVL BP, SP // Restore real SP
MOVL $0, m_vdsoSP(SI)
// Restore vdsoPC, vdsoSP
// We don't worry about being signaled between the two stores.
// If we are not in a signal handler, we'll restore vdsoSP to 0,
// and no one will care about vdsoPC. If we are in a signal handler,
// we cannot receive another signal.
MOVL 4(SP), CX
MOVL CX, m_vdsoSP(SI)
MOVL 0(SP), CX
MOVL CX, m_vdsoPC(SI)
// sec is in AX, nsec in BX
// convert to DX:AX nsec

56
src/runtime/sys_linux_amd64.s
View File

@ -206,7 +206,7 @@ TEXT runtime·mincore(SB),NOSPLIT,$0-28
// func walltime1() (sec int64, nsec int32)
// non-zero frame-size means bp is saved and restored
TEXT runtime·walltime1(SB),NOSPLIT,$8-12
TEXT runtime·walltime1(SB),NOSPLIT,$16-12
// We don't know how much stack space the VDSO code will need,
// so switch to g0.
// In particular, a kernel configured with CONFIG_OPTIMIZE_INLINING=n
@ -221,6 +221,13 @@ TEXT runtime·walltime1(SB),NOSPLIT,$8-12
MOVQ g_m(AX), BX // BX unchanged by C code.
// Set vdsoPC and vdsoSP for SIGPROF traceback.
// Save the old values on stack and restore them on exit,
// so this function is reentrant.
MOVQ m_vdsoPC(BX), CX
MOVQ m_vdsoSP(BX), DX
MOVQ CX, 0(SP)
MOVQ DX, 8(SP)
LEAQ sec+0(FP), DX
MOVQ -8(DX), CX
MOVQ CX, m_vdsoPC(BX)
@ -244,8 +251,17 @@ noswitch:
CALL AX
MOVQ 0(SP), AX // sec
MOVQ 8(SP), DX // nsec
ret:
MOVQ BP, SP // Restore real SP
MOVQ $0, m_vdsoSP(BX)
// Restore vdsoPC, vdsoSP
// We don't worry about being signaled between the two stores.
// If we are not in a signal handler, we'll restore vdsoSP to 0,
// and no one will care about vdsoPC. If we are in a signal handler,
// we cannot receive another signal.
MOVQ 8(SP), CX
MOVQ CX, m_vdsoSP(BX)
MOVQ 0(SP), CX
MOVQ CX, m_vdsoPC(BX)
MOVQ AX, sec+0(FP)
MOVL DX, nsec+8(FP)
RET
@ -257,15 +273,10 @@ fallback:
MOVQ 0(SP), AX // sec
MOVL 8(SP), DX // usec
IMULQ $1000, DX
MOVQ BP, SP // Restore real SP
MOVQ $0, m_vdsoSP(BX)
MOVQ AX, sec+0(FP)
MOVL DX, nsec+8(FP)
RET
JMP ret
// func nanotime1() int64
// non-zero frame-size means bp is saved and restored
TEXT runtime·nanotime1(SB),NOSPLIT,$8-8
TEXT runtime·nanotime1(SB),NOSPLIT,$16-8
// Switch to g0 stack. See comment above in runtime·walltime.
MOVQ SP, BP // Save old SP; BP unchanged by C code.
@ -275,6 +286,13 @@ TEXT runtime·nanotime1(SB),NOSPLIT,$8-8
MOVQ g_m(AX), BX // BX unchanged by C code.
// Set vdsoPC and vdsoSP for SIGPROF traceback.
// Save the old values on stack and restore them on exit,
// so this function is reentrant.
MOVQ m_vdsoPC(BX), CX
MOVQ m_vdsoSP(BX), DX
MOVQ CX, 0(SP)
MOVQ DX, 8(SP)
LEAQ ret+0(FP), DX
MOVQ -8(DX), CX
MOVQ CX, m_vdsoPC(BX)
@ -298,8 +316,17 @@ noswitch:
CALL AX
MOVQ 0(SP), AX // sec
MOVQ 8(SP), DX // nsec
ret:
MOVQ BP, SP // Restore real SP
MOVQ $0, m_vdsoSP(BX)
// Restore vdsoPC, vdsoSP
// We don't worry about being signaled between the two stores.
// If we are not in a signal handler, we'll restore vdsoSP to 0,
// and no one will care about vdsoPC. If we are in a signal handler,
// we cannot receive another signal.
MOVQ 8(SP), CX
MOVQ CX, m_vdsoSP(BX)
MOVQ 0(SP), CX
MOVQ CX, m_vdsoPC(BX)
// sec is in AX, nsec in DX
// return nsec in AX
IMULQ $1000000000, AX
@ -313,15 +340,8 @@ fallback:
CALL AX
MOVQ 0(SP), AX // sec
MOVL 8(SP), DX // usec
MOVQ BP, SP // Restore real SP
MOVQ $0, m_vdsoSP(BX)
IMULQ $1000, DX
// sec is in AX, nsec in DX
// return nsec in AX
IMULQ $1000000000, AX
ADDQ DX, AX
MOVQ AX, ret+0(FP)
RET
JMP ret
TEXT runtime·rtsigprocmask(SB),NOSPLIT,$0-28
MOVL how+0(FP), DI

36
src/runtime/sys_linux_arm.s
View File

@ -242,7 +242,7 @@ TEXT runtime·mincore(SB),NOSPLIT,$0
MOVW R0, ret+12(FP)
RET
TEXT runtime·walltime1(SB),NOSPLIT,$0-12
TEXT runtime·walltime1(SB),NOSPLIT,$8-12
// We don't know how much stack space the VDSO code will need,
// so switch to g0.
@ -252,6 +252,13 @@ TEXT runtime·walltime1(SB),NOSPLIT,$0-12
MOVW g_m(g), R5 // R5 is unchanged by C code.
// Set vdsoPC and vdsoSP for SIGPROF traceback.
// Save the old values on stack and restore them on exit,
// so this function is reentrant.
MOVW m_vdsoPC(R5), R1
MOVW m_vdsoSP(R5), R2
MOVW R1, 4(R13)
MOVW R2, 8(R13)
MOVW LR, m_vdsoPC(R5)
MOVW R13, m_vdsoSP(R5)
@ -312,8 +319,15 @@ finish:
MOVW 12(R13), R2 // nsec
MOVW R4, R13 // Restore real SP
MOVW $0, R1
// Restore vdsoPC, vdsoSP
// We don't worry about being signaled between the two stores.
// If we are not in a signal handler, we'll restore vdsoSP to 0,
// and no one will care about vdsoPC. If we are in a signal handler,
// we cannot receive another signal.
MOVW 8(R13), R1
MOVW R1, m_vdsoSP(R5)
MOVW 4(R13), R1
MOVW R1, m_vdsoPC(R5)
MOVW R0, sec_lo+0(FP)
MOVW R1, sec_hi+4(FP)
@ -321,7 +335,7 @@ finish:
RET
// int64 nanotime1(void)
TEXT runtime·nanotime1(SB),NOSPLIT,$0-8
TEXT runtime·nanotime1(SB),NOSPLIT,$8-8
// Switch to g0 stack. See comment above in runtime·walltime.
// Save old SP. Use R13 instead of SP to avoid linker rewriting the offsets.
@ -330,6 +344,13 @@ TEXT runtime·nanotime1(SB),NOSPLIT,$0-8
MOVW g_m(g), R5 // R5 is unchanged by C code.
// Set vdsoPC and vdsoSP for SIGPROF traceback.
// Save the old values on stack and restore them on exit,
// so this function is reentrant.
MOVW m_vdsoPC(R5), R1
MOVW m_vdsoSP(R5), R2
MOVW R1, 4(R13)
MOVW R2, 8(R13)
MOVW LR, m_vdsoPC(R5)
MOVW R13, m_vdsoSP(R5)
@ -390,8 +411,15 @@ finish:
MOVW 12(R13), R2 // nsec
MOVW R4, R13 // Restore real SP
MOVW $0, R4
// Restore vdsoPC, vdsoSP
// We don't worry about being signaled between the two stores.
// If we are not in a signal handler, we'll restore vdsoSP to 0,
// and no one will care about vdsoPC. If we are in a signal handler,
// we cannot receive another signal.
MOVW 8(R13), R4
MOVW R4, m_vdsoSP(R5)
MOVW 4(R13), R4
MOVW R4, m_vdsoPC(R5)
MOVW $1000000000, R3
MULLU R0, R3, (R1, R0)

34
src/runtime/sys_linux_arm64.s
View File

@ -214,6 +214,13 @@ TEXT runtime·walltime1(SB),NOSPLIT,$24-12
MOVD g_m(g), R21 // R21 = m
// Set vdsoPC and vdsoSP for SIGPROF traceback.
// Save the old values on stack and restore them on exit,
// so this function is reentrant.
MOVD m_vdsoPC(R21), R2
MOVD m_vdsoSP(R21), R3
MOVD R2, 8(RSP)
MOVD R3, 16(RSP)
MOVD LR, m_vdsoPC(R21)
MOVD R20, m_vdsoSP(R21)
@ -269,7 +276,15 @@ finish:
MOVD 8(RSP), R5 // nsec
MOVD R20, RSP // restore SP
MOVD $0, m_vdsoSP(R21) // clear vdsoSP
// Restore vdsoPC, vdsoSP
// We don't worry about being signaled between the two stores.
// If we are not in a signal handler, we'll restore vdsoSP to 0,
// and no one will care about vdsoPC. If we are in a signal handler,
// we cannot receive another signal.
MOVD 16(RSP), R1
MOVD R1, m_vdsoSP(R21)
MOVD 8(RSP), R1
MOVD R1, m_vdsoPC(R21)
MOVD R3, sec+0(FP)
MOVW R5, nsec+8(FP)
@ -282,6 +297,13 @@ TEXT runtime·nanotime1(SB),NOSPLIT,$24-8
MOVD g_m(g), R21 // R21 = m
// Set vdsoPC and vdsoSP for SIGPROF traceback.
// Save the old values on stack and restore them on exit,
// so this function is reentrant.
MOVD m_vdsoPC(R21), R2
MOVD m_vdsoSP(R21), R3
MOVD R2, 8(RSP)
MOVD R3, 16(RSP)
MOVD LR, m_vdsoPC(R21)
MOVD R20, m_vdsoSP(R21)
@ -337,7 +359,15 @@ finish:
MOVD 8(RSP), R5 // nsec
MOVD R20, RSP // restore SP
MOVD $0, m_vdsoSP(R21) // clear vdsoSP
// Restore vdsoPC, vdsoSP
// We don't worry about being signaled between the two stores.
// If we are not in a signal handler, we'll restore vdsoSP to 0,
// and no one will care about vdsoPC. If we are in a signal handler,
// we cannot receive another signal.
MOVD 16(RSP), R1
MOVD R1, m_vdsoSP(R21)
MOVD 8(RSP), R1
MOVD R1, m_vdsoPC(R21)
// sec is in R3, nsec in R5
// return nsec in R3

38
src/runtime/sys_linux_mips64x.s
View File

@ -214,13 +214,20 @@ TEXT runtime·mincore(SB),NOSPLIT|NOFRAME,$0-28
RET
// func walltime1() (sec int64, nsec int32)
TEXT runtime·walltime1(SB),NOSPLIT,$16
TEXT runtime·walltime1(SB),NOSPLIT,$16-12
MOVV R29, R16 // R16 is unchanged by C code
MOVV R29, R1
MOVV g_m(g), R17 // R17 = m
// Set vdsoPC and vdsoSP for SIGPROF traceback.
// Save the old values on stack and restore them on exit,
// so this function is reentrant.
MOVV m_vdsoPC(R17), R2
MOVV m_vdsoSP(R17), R3
MOVV R2, 8(R29)
MOVV R3, 16(R29)
MOVV R31, m_vdsoPC(R17)
MOVV R29, m_vdsoSP(R17)
@ -249,7 +256,15 @@ finish:
MOVV 8(R29), R5 // nsec
MOVV R16, R29 // restore SP
MOVV R0, m_vdsoSP(R17) // clear vdsoSP
// Restore vdsoPC, vdsoSP
// We don't worry about being signaled between the two stores.
// If we are not in a signal handler, we'll restore vdsoSP to 0,
// and no one will care about vdsoPC. If we are in a signal handler,
// we cannot receive another signal.
MOVV 16(R29), R1
MOVV R1, m_vdsoSP(R17)
MOVV 8(R29), R1
MOVV R1, m_vdsoPC(R17)
MOVV R3, sec+0(FP)
MOVW R5, nsec+8(FP)
@ -260,13 +275,20 @@ fallback:
SYSCALL
JMP finish
TEXT runtime·nanotime1(SB),NOSPLIT,$16
TEXT runtime·nanotime1(SB),NOSPLIT,$16-8
MOVV R29, R16 // R16 is unchanged by C code
MOVV R29, R1
MOVV g_m(g), R17 // R17 = m
// Set vdsoPC and vdsoSP for SIGPROF traceback.
// Save the old values on stack and restore them on exit,
// so this function is reentrant.
MOVV m_vdsoPC(R17), R2
MOVV m_vdsoSP(R17), R3
MOVV R2, 8(R29)
MOVV R3, 16(R29)
MOVV R31, m_vdsoPC(R17)
MOVV R29, m_vdsoSP(R17)
@ -295,7 +317,15 @@ finish:
MOVV 8(R29), R5 // nsec
MOVV R16, R29 // restore SP
MOVV R0, m_vdsoSP(R17) // clear vdsoSP
// Restore vdsoPC, vdsoSP
// We don't worry about being signaled between the two stores.
// If we are not in a signal handler, we'll restore vdsoSP to 0,
// and no one will care about vdsoPC. If we are in a signal handler,
// we cannot receive another signal.
MOVV 16(R29), R1
MOVV R1, m_vdsoSP(R17)
MOVV 8(R29), R1
MOVV R1, m_vdsoPC(R17)
// sec is in R3, nsec in R5
// return nsec in R3

40
src/runtime/sys_linux_ppc64x.s
View File

@ -185,7 +185,7 @@ TEXT runtime·mincore(SB),NOSPLIT|NOFRAME,$0-28
RET
// func walltime1() (sec int64, nsec int32)
TEXT runtime·walltime1(SB),NOSPLIT,$16
TEXT runtime·walltime1(SB),NOSPLIT,$16-12
MOVD R1, R15 // R15 is unchanged by C code
MOVD g_m(g), R21 // R21 = m
@ -196,6 +196,13 @@ TEXT runtime·walltime1(SB),NOSPLIT,$16
BEQ fallback
// Set vdsoPC and vdsoSP for SIGPROF traceback.
// Save the old values on stack and restore them on exit,
// so this function is reentrant.
MOVD m_vdsoPC(R21), R4
MOVD m_vdsoSP(R21), R5
MOVD R4, 32(R1)
MOVD R5, 40(R1)
MOVD LR, R14
MOVD R14, m_vdsoPC(R21)
MOVD R15, m_vdsoSP(R21)
@ -214,11 +221,20 @@ noswitch:
MOVD R1, R4
BL (CTR) // Call from VDSO
MOVD $0, R0 // Restore R0
MOVD R0, m_vdsoSP(R21) // Clear vdsoSP
MOVD 0(R1), R3 // sec
MOVD 8(R1), R5 // nsec
MOVD R15, R1 // Restore SP
// Restore vdsoPC, vdsoSP
// We don't worry about being signaled between the two stores.
// If we are not in a signal handler, we'll restore vdsoSP to 0,
// and no one will care about vdsoPC. If we are in a signal handler,
// we cannot receive another signal.
MOVD 40(R1), R6
MOVD R6, m_vdsoSP(R21)
MOVD 32(R1), R6
MOVD R6, m_vdsoPC(R21)
finish:
MOVD R3, sec+0(FP)
MOVW R5, nsec+8(FP)
@ -232,7 +248,7 @@ fallback:
MOVD 40(R1), R5
JMP finish
TEXT runtime·nanotime1(SB),NOSPLIT,$16
TEXT runtime·nanotime1(SB),NOSPLIT,$16-8
MOVD $1, R3 // CLOCK_MONOTONIC
MOVD R1, R15 // R15 is unchanged by C code
@ -243,6 +259,13 @@ TEXT runtime·nanotime1(SB),NOSPLIT,$16
BEQ fallback
// Set vdsoPC and vdsoSP for SIGPROF traceback.
// Save the old values on stack and restore them on exit,
// so this function is reentrant.
MOVD m_vdsoPC(R21), R4
MOVD m_vdsoSP(R21), R5
MOVD R4, 32(R1)
MOVD R5, 40(R1)
MOVD LR, R14 // R14 is unchanged by C code
MOVD R14, m_vdsoPC(R21)
MOVD R15, m_vdsoSP(R21)
@ -261,11 +284,20 @@ noswitch:
MOVD R1, R4
BL (CTR) // Call from VDSO
MOVD $0, R0 // Restore R0
MOVD $0, m_vdsoSP(R21) // Clear vdsoSP
MOVD 0(R1), R3 // sec
MOVD 8(R1), R5 // nsec
MOVD R15, R1 // Restore SP
// Restore vdsoPC, vdsoSP
// We don't worry about being signaled between the two stores.
// If we are not in a signal handler, we'll restore vdsoSP to 0,
// and no one will care about vdsoPC. If we are in a signal handler,
// we cannot receive another signal.
MOVD 40(R1), R6
MOVD R6, m_vdsoSP(R21)
MOVD 32(R1), R6
MOVD R6, m_vdsoPC(R21)
finish:
// sec is in R3, nsec in R5
// return nsec in R3