Bug 450536

Summary: Powerpc: valgrind throws 'facility scv unavailable exception'
Product: [Developer tools] valgrind Reporter: Carl Love <cel>
Component: vexAssignee: Julian Seward <jseward>
Status: CLOSED FIXED    
Severity: normal    
Priority: NOR    
Version: 3.18.1   
Target Milestone: ---   
Platform: Other   
OS: Linux   
Latest Commit: Version Fixed In:
Sentry Crash Report:
Attachments: Powerpc fix checking for scv support add check for scv instruction

Description Carl Love 2022-02-18 18:54:06 UTC 
'valgrind ls' command throws "Facility 'SCV' unavailable (12), exception at 0x5806aad0, MSR=800000000280f033", on kernel where SCV support is not there.
 
Contact Information = nasastry@in.ibm.com 
 
---uname output---
Linux ltcden14-lp8 4.18.0-359.el8.bz196163.ppc64le #1 SMP Sat Jan 29 01:35:20 EST 2022 ppc64le ppc64le ppc64le GNU/Linux
 
Machine Type = IBM,9080-HEX 
 
---Debugger---
A debugger is not configured
 
---Steps to Reproduce---
 1. Install valgrind-3.18.1-6.el8.ppc64le if not installed
2. Run 'valgrind ls' command
3. Check the 'dmesg'
...
Facility 'SCV' unavailable (12), exception at 0x5806aad0, MSR=800000000280f033


[root@ltcden14-lp8 ~]# LD_SHOW_AUXV=1 /bin/true
AT_DCACHEBSIZE:  0x80
AT_ICACHEBSIZE:  0x80
AT_UCACHEBSIZE:  0x0
AT_SYSINFO_EHDR: 0x7fffbacb0000
AT_??? (0x28): 0xc000
AT_??? (0x29): 0x60080
AT_??? (0x2a): 0x8000
AT_??? (0x2b): 0x80080
AT_??? (0x2c): 0x100000
AT_??? (0x2d): 0x80080
AT_??? (0x2e): 0x400000
AT_??? (0x2f): 0x100080
AT_HWCAP:        true_le archpmu vsx arch_2_06 dfp ic_snoop smt mmu fpu altivec ppc64 ppc32
AT_PAGESZ:       65536
AT_CLKTCK:       100
AT_PHDR:         0x13bd60040
AT_PHENT:        56
AT_PHNUM:        9
AT_BASE:         0x7fffbacd0000
AT_FLAGS:        0x0
AT_ENTRY:        0x13bd61a7c
AT_UID:          0
AT_EUID:         0
AT_GID:          0
AT_EGID:         0
AT_SECURE:       0
AT_RANDOM:       0x7fffdf1bb070
AT_HWCAP2:       mma arch_3_1 darn ieee128 arch_3_00 vcrypto tar isel ebb dscr arch_2_07
AT_EXECFN:       /bin/true
AT_PLATFORM:     power10
AT_BASE_PLATFORM:power10
[root@ltcden14-lp8 ~]# grep model /proc/cpuinfo
model		: IBM,9080-HEX
 
Userspace tool common name: valgrind 

Userspace rpm: valgrind-3.18.1-6.el8.ppc64le 
 
The userspace tool has the following bit modes: 64-bit 

Userspace tool obtained from project website:  na
Comment 1 Carl Love 2022-02-18 19:01:16 UTC 
Created attachment 146924 [details]
Powerpc fix checking for scv support add check for scv instruction

The attached patch fixes the issue of testing the scv instruction which results in an entry in dmesg.  It also adds the missing check for scv support in VEX/priv/guest_ppc_toIR.c, function  dis_syslink().
Comment 2 Carl Love 2022-02-18 19:14:19 UTC 
patch committed

commit 7f11271403219d21c46e3b831cc1709336e792f1 (HEAD -> master, origin/master, origin/HEAD)
Author: Carl Love <carll@us.ibm.com>
Date:   Fri Feb 11 14:07:20 2022 -0600

    Powerpc: Fix checking for scv support, add check to scv instruction parsing.
    
    The check for the scv instruction in coregrind/m_machine.c issues an scv
    instruction and uses sigill to determine if the instruction is supported.
    Issuing scv on systems that don't support scv, i.e. scv support is not in
    HWCAPS2, generates a message in dmesg "Facility 'SCV' unavailable (12),
    exception".
    
    This patch removes the sigill based scv instruction test from
    coregrind/m_machine.c.  The scv support is now determined by reading the
    HWCAPS2 in setup_client_stack().  VG_(machine_ppc64_set_scv_support) is
    called to set the flag ppc_scv_supported in struct VexArchInfo.
    
    The allow_scv flag is added in disInstr_PPC_WRK.  The allow_scv flag is
    used to ensure the host has support for scv before generating the iops for
    the scv instruction.
Comment 3 Carl Love 2022-02-19 04:20:23 UTC 
Patch committed

commit 7f11271403219d21c46e3b831cc1709336e792f1 (HEAD -> master, origin/master, origin/HEAD)
Author: Carl Love <carll@us.ibm.com>
Date:   Fri Feb 11 14:07:20 2022 -0600

    Powerpc: Fix checking for scv support, add check to scv instruction parsing.
    
    The check for the scv instruction in coregrind/m_machine.c issues an scv
    instruction and uses sigill to determine if the instruction is supported.
    Issuing scv on systems that don't support scv, i.e. scv support is not in
    HWCAPS2, generates a message in dmesg "Facility 'SCV' unavailable (12),
    exception".
    
    This patch removes the sigill based scv instruction test from
    coregrind/m_machine.c.  The scv support is now determined by reading the
    HWCAPS2 in setup_client_stack().  VG_(machine_ppc64_set_scv_support) is
    called to set the flag ppc_scv_supported in struct VexArchInfo.
    
    The allow_scv flag is added in disInstr_PPC_WRK.  The allow_scv flag is
    used to ensure the host has support for scv before generating the iops for
    the scv instruction.