Bug 387821 - ptrace: AltiVec PTRACE_GETVRREGS returns invalid VRSAVE
ptrace: AltiVec PTRACE_GETVRREGS returns invalid VRSAVE
Product: Fedora
Classification: Fedora
Component: kernel (Show other bugs)
ppc64 Linux
low Severity low
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Assigned To: Roland McGrath
Fedora Extras Quality Assurance
Depends On: 367221
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Reported: 2007-11-16 17:48 EST by Jan Kratochvil
Modified: 2007-12-04 19:10 EST (History)
2 users (show)

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Fixed In Version:
Doc Type: Bug Fix
Doc Text:
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Clone Of:
Last Closed: 2007-12-04 19:10:02 EST
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RHEL 7.3 requirements from Atomic Host:
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Attachments (Terms of Use)
kernel reportedly-fix by Roland McGrath. (1.98 KB, patch)
2007-11-16 17:48 EST, Jan Kratochvil
no flags Details | Diff

  None (edit)
Description Jan Kratochvil 2007-11-16 17:48:28 EST
Description of problem:
PTRACE_GETVRREGS call returns value with an invalid VRSAVE value.

Version-Release number of selected component (if applicable):

How reproducible:

Steps to Reproduce:
1. wget -O powerpc-altivec.c
2. gcc -o powerpc-altivec powerpc-altivec.c -Wall -ggdb2 -m64 -D_GNU_SOURCE
3. ./powerpc-altivec;echo $?
Actual results:
[132] 0xa5a5a5a5

Expected results:

Additional info:
-m64 in command `2.' can be replacted with -m32 with the same results.

While it should be fixed since kernel- according to the CVS
logs my tests do not confirm it.
Comment 1 Jan Kratochvil 2007-11-16 17:48:28 EST
Created attachment 261921 [details]
kernel reportedly-fix by Roland McGrath.
Comment 3 Roland McGrath 2007-11-19 17:14:18 EST is the one I've tested.
Comment 5 Jan Kratochvil 2007-11-19 17:33:12 EST
Roland, while I believe your patch is right there is some problem that
  mtspr 256,0x01010101
value does not get mapped into `thread.vrsave'.  It should be a problem outside
of utrace.
Comment 6 Roland McGrath 2007-11-19 18:40:25 EST
This flavor of machine simply lacks the Altivec hardware support, though the
ppc64 kernel always supports it when it's there.  I've fixed the test to handle

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