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cmd/compile: nacl/arm is broken #19884

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davecheney opened this issue Apr 7, 2017 · 5 comments

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commented Apr 7, 2017

Please answer these questions before submitting your issue. Thanks!

What version of Go are you using (go version)?

$ go version
go version devel +03d1aa6 Fri Apr 7 04:46:42 2017 +0000 linux/arm

What operating system and processor architecture are you using (go env)?

linux/arm

What did you do?

pi@raspberrypi:~/go/src $ /home/pi/bin/sel_ldr_arm --reserved_at_zero=0x0000000040002000  -S -e -v ./bytes.test -test.v
sel_ldr argument list:
/home/pi/bin/sel_ldr_arm --reserved_at_zero=0x0000000040002000 -S -e -v ./bytes.test -test.v
[32594,1996328960:23:03:27.124074] NaClPerfCounterInterval(NaClAppLoadFile __start__:PreAllocAddrSpace): 78 microsecs
[32594,1996328960:23:03:27.124361] Native Client module will be loaded at base address 0x0000000000000000
[32594,1996328960:23:03:27.124449] NaClPerfCounterInterval(NaClAppLoadFile PreAllocAddrSpace:*AllocAddrSpace): 377 microsecs
[32594,1996328960:23:03:27.132401] NaClPerfCounterInterval(NaClAppLoadFile *AllocAddrSpace:*NaClElfImageLoad): 7947 microsecs
[32594,1996328960:23:03:27.132620] NaClPerfCounterInterval(NaClAppLoadFile *NaClElfImageLoad:*MakeDynText): 224 microsecs
[32594,1996328960:23:03:27.208303] VALIDATION FAILED.
[32594,1996328960:23:03:27.208363] Run sel_ldr in debug mode to ignore validation failure.
[32594,1996328960:23:03:27.208383] Run ncval <module-name> for validation error details.
[32594,1996328960:23:03:27.208401] NaClPerfCounterInterval(NaClAppLoadFile *MakeDynText:*ValidateImg): 75782 microsecs
[32594,1996328960:23:03:27.208423] NaClPerfCounterInterval(NaClAppLoadFile __start__:EndLoadFile): 84430 microsecs
[32594,1996328960:23:03:27.208462] Error while loading "./bytes.test": Validation failure. File violates Native Client safety rules.
Using the wrong type of nexe (nacl-x86-32 on an x86-64 or vice versa)
or a corrupt nexe file may be responsible for this error.
[32594,1996328960:23:03:27.208488] NaClPerfCounterInterval(SelMain __start__:AppLoadEnd): 93567 microsecs
[32594,1996328960:23:03:27.208506] NACL: Application output follows
[32594,1996328960:23:03:27.208525] NaClAppStartModule: error loading module
Dumping vmmap.
In PrintVmmap
Done.

What did you expect to see?

test complete successfully

What did you see instead?

echo code 1

@davecheney davecheney added this to the Go1.9 milestone Apr 7, 2017

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commented Apr 7, 2017

bytes.test.gz

^ failing nacl binary

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commented Apr 7, 2017

(gdb) disassemble 0xa96ac
Dump of assembler code for function runtime.save_g:
   0x000a96a0 <+0>:     mov     r0, r10
   0x000a96a4 <+4>:     bic     lr, lr, #-1073741809    ; 0xc000000f
   0x000a96a8 <+8>:     bx      lr
   0x000a96ac <+12>:    mrc     15, 0, r0, cr13, cr0, {3}               <<<<<<<<<<<<<<
   0x000a96b0 <+16>:    bic     r0, r0, #3
   0x000a96b4 <+20>:    ldr     r11, [pc, #40]  ; 0xa96e4 <runtime.save_g+68>
   0x000a96b8 <+24>:    add     r0, r0, r11
   0x000a96bc <+28>:    nop                     ; (mov r0, r0)
   0x000a96c0 <+32>:    bic     r0, r0, #-1073741824    ; 0xc0000000
   0x000a96c4 <+36>:    str     r10, [r0]
   0x000a96c8 <+40>:    mov     r0, r10
   0x000a96cc <+44>:    nop                     ; (mov r0, r0)
   0x000a96d0 <+48>:    bic     lr, lr, #-1073741809    ; 0xc000000f
   0x000a96d4 <+52>:    bx      lr
   0x000a96d8 <+56>:    b       0xa96d8 <runtime.save_g+56>
   0x000a96dc <+60>:    nop                     ; (mov r0, r0)
   0x000a96e0 <+64>:    bkpt    0x5be0
   0x000a96e4 <+68>:    andeq   r0, r0, r8
   0x000a96e8 <+72>:    nop                     ; (mov r0, r0)
   0x000a96ec <+76>:    nop                     ; (mov r0, r0)
End of assembler dump.
(gdb) disassemble 0xa96f8
Dump of assembler code for function runtime.load_g:
   0x000a96f0 <+0>:     bic     lr, lr, #-1073741809    ; 0xc000000f
   0x000a96f4 <+4>:     bx      lr
   0x000a96f8 <+8>:     mrc     15, 0, r0, cr13, cr0, {3} <<<<<<<<<<<<
   0x000a96fc <+12>:    bic     r0, r0, #3
   0x000a9700 <+16>:    ldr     r11, [pc, #28]  ; 0xa9724 <runtime.load_g+52>
   0x000a9704 <+20>:    add     r0, r0, r11
   0x000a9708 <+24>:    bic     r0, r0, #-1073741824    ; 0xc0000000
   0x000a970c <+28>:    ldr     r10, [r0]
   0x000a9710 <+32>:    bic     lr, lr, #-1073741809    ; 0xc000000f
   0x000a9714 <+36>:    bx      lr
   0x000a9718 <+40>:    b       0xa9718 <runtime.load_g+40>
   0x000a971c <+44>:    nop                     ; (mov r0, r0)
   0x000a9720 <+48>:    bkpt    0x5be0
   0x000a9724 <+52>:    andeq   r0, r0, r8
   0x000a9728 <+56>:    nop                     ; (mov r0, r0)
   0x000a972c <+60>:    nop                     ; (mov r0, r0)

Are the offending instructions. mrc is not permitted by nacl.

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commented Apr 7, 2017

That's odd

TEXT runtime·save_g(SB),NOSPLIT,$-4
#ifdef GOOS_nacl
        // nothing to do as nacl/arm does not use TLS at all.
        MOVW    g, R0 // preserve R0 across call to setg<>
        RET
#endif

Should have avoided fetching the tls register.

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commented Apr 8, 2017

Bisect?

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commented Apr 8, 2017

CL https://golang.org/cl/40111 mentions this issue.

@cherrymui cherrymui self-assigned this Apr 8, 2017

@gopherbot gopherbot closed this in 0020b8a Apr 8, 2017

lparth added a commit to lparth/go that referenced this issue Apr 13, 2017

runtime: prevent TLS fetching instructions from being assembled on Na…
…Cl/ARM

They are dead code already, but the verifier is still not happy.
Don't assemble them at all.

Looks like it has been like that for long. I don't know why it
was ok. Maybe the verifier is now more picky?

Fixes golang#19884.

Change-Id: Ib806fb73ca469789dec56f52d484cf8baf7a245c
Reviewed-on: https://go-review.googlesource.com/40111
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
Reviewed-by: Dave Cheney <dave@cheney.net>

@golang golang locked and limited conversation to collaborators Apr 8, 2018

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