runtime,runtime/cgo: save callee-saved FP register on arm

Other GOARCHs already handle their callee-saved FP registers, but
arm was missing. Without this change, code using Cgo and floating
point code might fail in mysterious and hard to debug ways.

There are no floating point registers when GOARM=5, so skip the
registers when runtime.goarm < 6.

darwin/arm doesn't support GOARM=5, so the check is left out of
rt0_darwin_arm.s.

Fixes #14876

Change-Id: I6bcb90a76df3664d8ba1f33123a74b1eb2c9f8b2
Reviewed-on: https://go-review.googlesource.com/23140
Run-TryBot: Elias Naur <elias.naur@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Minux Ma <minux@golang.org>

diff --git a/src/runtime/cgo/asm_arm.s b/src/runtime/cgo/asm_arm.s
index 08472b6ab76ad9a00c3cca946e1a2245873d40e0..0f354220bbf0b75cb130fef582de1b0cb45c4b79 100644 (file)
--- a/src/runtime/cgo/asm_arm.s
+++ b/src/runtime/cgo/asm_arm.s
@@ -16,8 +16,40 @@ TEXT crosscall2(SB),NOSPLIT,$-4
         *  Additionally, runtime·load_g will clobber R0, so we need to save R0
         *  nevertheless.
         */
+       SUB     $(8*9), R13 // Reserve space for the floating point registers.
        MOVM.WP [R0, R1, R2, R3, R4, R5, R6, R7, R8, R9, g, R11, R12, R14], (R13)
+
+       // Skip floating point registers on GOARM < 6.
+       MOVB    runtime·goarm(SB), R11
+       CMP $6, R11
+       BLT skipfpsave
+       MOVD    F8, (14*4+8*1)(R13)
+       MOVD    F9, (14*4+8*2)(R13)
+       MOVD    F10, (14*4+8*3)(R13)
+       MOVD    F11, (14*4+8*4)(R13)
+       MOVD    F12, (14*4+8*5)(R13)
+       MOVD    F13, (14*4+8*6)(R13)
+       MOVD    F14, (14*4+8*7)(R13)
+       MOVD    F15, (14*4+8*8)(R13)
+
+skipfpsave:
        BL      runtime·load_g(SB)
        MOVW    R15, R14 // R15 is PC.
        MOVW    0(R13), R15
-       MOVM.IAW        (R13), [R0, R1, R2, R3, R4, R5, R6, R7, R8, R9, g, R11, R12, R15]
+
+       MOVB    runtime·goarm(SB), R11
+       CMP $6, R11
+       BLT skipfprest
+       MOVD    (14*4+8*1)(R13), F8
+       MOVD    (14*4+8*2)(R13), F9
+       MOVD    (14*4+8*3)(R13), F10
+       MOVD    (14*4+8*4)(R13), F11
+       MOVD    (14*4+8*5)(R13), F12
+       MOVD    (14*4+8*6)(R13), F13
+       MOVD    (14*4+8*7)(R13), F14
+       MOVD    (14*4+8*8)(R13), F15
+
+skipfprest:
+       MOVM.IAW        (R13), [R0, R1, R2, R3, R4, R5, R6, R7, R8, R9, g, R11, R12, R14]
+       ADD     $(8*9), R13
+       MOVW    R14, R15

diff --git a/src/runtime/rt0_darwin_arm.s b/src/runtime/rt0_darwin_arm.s
index 59733d3ff60fe05d1ba4cb474549587f3bb730c4..526d88f13d2430d8f21a3a5dff0ae648312b7a07 100644 (file)
--- a/src/runtime/rt0_darwin_arm.s
+++ b/src/runtime/rt0_darwin_arm.s
@@ -16,7 +16,7 @@ TEXT _rt0_arm_darwin(SB),7,$-4
 //
 // Note that all currently shipping darwin/arm platforms require
 // cgo and do not support c-shared.
-TEXT _rt0_arm_darwin_lib(SB),NOSPLIT,$32
+TEXT _rt0_arm_darwin_lib(SB),NOSPLIT,$104
        // Preserve callee-save registers.
        MOVW    R4, 12(R13)
        MOVW    R5, 16(R13)
@@ -25,6 +25,15 @@ TEXT _rt0_arm_darwin_lib(SB),NOSPLIT,$32
        MOVW    R8, 28(R13)
        MOVW    R11, 32(R13)
 
+       MOVD    F8, (32+8*1)(R13)
+       MOVD    F9, (32+8*2)(R13)
+       MOVD    F10, (32+8*3)(R13)
+       MOVD    F11, (32+8*4)(R13)
+       MOVD    F12, (32+8*5)(R13)
+       MOVD    F13, (32+8*6)(R13)
+       MOVD    F14, (32+8*7)(R13)
+       MOVD    F15, (32+8*8)(R13)
+
        MOVW  R0, _rt0_arm_darwin_lib_argc<>(SB)
        MOVW  R1, _rt0_arm_darwin_lib_argv<>(SB)
 
@@ -57,6 +66,14 @@ rr:
        MOVW    24(R13), R7
        MOVW    28(R13), R8
        MOVW    32(R13), R11
+       MOVD    (32+8*1)(R13), F8
+       MOVD    (32+8*2)(R13), F9
+       MOVD    (32+8*3)(R13), F10
+       MOVD    (32+8*4)(R13), F11
+       MOVD    (32+8*5)(R13), F12
+       MOVD    (32+8*6)(R13), F13
+       MOVD    (32+8*7)(R13), F14
+       MOVD    (32+8*8)(R13), F15
        RET
 
 

diff --git a/src/runtime/rt0_linux_arm.s b/src/runtime/rt0_linux_arm.s
index a4419b898e31ef5a85ff5a65ac5e5b86ea7a3731..597e642adb717786958c31c945c180fec869d1b2 100644 (file)
--- a/src/runtime/rt0_linux_arm.s
+++ b/src/runtime/rt0_linux_arm.s
@@ -12,7 +12,7 @@ TEXT _rt0_arm_linux(SB),NOSPLIT,$-4
 
 // When building with -buildmode=c-shared, this symbol is called when the shared
 // library is loaded.
-TEXT _rt0_arm_linux_lib(SB),NOSPLIT,$32
+TEXT _rt0_arm_linux_lib(SB),NOSPLIT,$104
        // Preserve callee-save registers. Raspberry Pi's dlopen(), for example,
        // actually cares that R11 is preserved.
        MOVW    R4, 12(R13)
@@ -22,6 +22,19 @@ TEXT _rt0_arm_linux_lib(SB),NOSPLIT,$32
        MOVW    R8, 28(R13)
        MOVW    R11, 32(R13)
 
+       // Skip floating point registers on GOARM < 6.
+       MOVB    runtime·goarm(SB), R11
+       CMP $6, R11
+       BLT skipfpsave
+       MOVD    F8, (32+8*1)(R13)
+       MOVD    F9, (32+8*2)(R13)
+       MOVD    F10, (32+8*3)(R13)
+       MOVD    F11, (32+8*4)(R13)
+       MOVD    F12, (32+8*5)(R13)
+       MOVD    F13, (32+8*6)(R13)
+       MOVD    F14, (32+8*7)(R13)
+       MOVD    F15, (32+8*8)(R13)
+skipfpsave:
        // Save argc/argv.
        MOVW    R0, _rt0_arm_linux_lib_argc<>(SB)
        MOVW    R1, _rt0_arm_linux_lib_argv<>(SB)
@@ -46,6 +59,18 @@ nocgo:
        BL      runtime·newosproc0(SB)
 rr:
        // Restore callee-save registers and return.
+       MOVB    runtime·goarm(SB), R11
+       CMP $6, R11
+       BLT skipfprest
+       MOVD    (32+8*1)(R13), F8
+       MOVD    (32+8*2)(R13), F9
+       MOVD    (32+8*3)(R13), F10
+       MOVD    (32+8*4)(R13), F11
+       MOVD    (32+8*5)(R13), F12
+       MOVD    (32+8*6)(R13), F13
+       MOVD    (32+8*7)(R13), F14
+       MOVD    (32+8*8)(R13), F15
+skipfprest:
        MOVW    12(R13), R4
        MOVW    16(R13), R5
        MOVW    20(R13), R6