From: Roger Pau Monne <roger.pau@citrix.com>
To: <xen-devel@lists.xenproject.org>
Cc: Roger Pau Monne <roger.pau@citrix.com>,
Jan Beulich <jbeulich@suse.com>,
Andrew Cooper <andrew.cooper3@citrix.com>, Wei Liu <wl@xen.org>
Subject: [PATCH 2/2] x86/pv: fix clang build without CONFIG_PV32
Date: Fri, 23 Apr 2021 11:43:43 +0200 [thread overview]
Message-ID: <20210423094343.5850-3-roger.pau@citrix.com> (raw)
In-Reply-To: <20210423094343.5850-1-roger.pau@citrix.com>
Clang reports the following build error without CONFIG_PV:
hypercall.c:253:10: error: variable 'op' is used uninitialized whenever 'if' condition is false [-Werror,-Wsometimes-uninitialized]
if ( !is_pv_32bit_vcpu(curr) )
^~~~~~~~~~~~~~~~~~~~~~~
hypercall.c:282:21: note: uninitialized use occurs here
return unlikely(op == __HYPERVISOR_iret)
^~
/root/src/xen/xen/include/xen/compiler.h:21:43: note: expanded from macro 'unlikely'
#define unlikely(x) __builtin_expect(!!(x),0)
^
hypercall.c:253:5: note: remove the 'if' if its condition is always true
if ( !is_pv_32bit_vcpu(curr) )
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
hypercall.c:251:21: note: initialize the variable 'op' to silence this warning
unsigned long op;
^
= 0
Rearrange the code in arch_do_multicall_call so that the if guards the
32bit branch and when CONFIG_PV32 is not set there's no conditional at
all.
Fixes: 527922008bc ('x86: slim down hypercall handling when !PV32')
Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
---
Should the is_pv_32bit_vcpu be wrapped in an unlikely hint?
---
xen/arch/x86/pv/hypercall.c | 18 +++++++++---------
1 file changed, 9 insertions(+), 9 deletions(-)
diff --git a/xen/arch/x86/pv/hypercall.c b/xen/arch/x86/pv/hypercall.c
index e30c59b6286..d573f74aa1e 100644
--- a/xen/arch/x86/pv/hypercall.c
+++ b/xen/arch/x86/pv/hypercall.c
@@ -250,34 +250,34 @@ enum mc_disposition arch_do_multicall_call(struct mc_state *state)
struct vcpu *curr = current;
unsigned long op;
- if ( !is_pv_32bit_vcpu(curr) )
+#ifdef CONFIG_PV32
+ if ( is_pv_32bit_vcpu(curr) )
{
- struct multicall_entry *call = &state->call;
+ struct compat_multicall_entry *call = &state->compat_call;
op = call->op;
if ( (op < ARRAY_SIZE(pv_hypercall_table)) &&
- pv_hypercall_table[op].native )
- call->result = pv_hypercall_table[op].native(
+ pv_hypercall_table[op].compat )
+ call->result = pv_hypercall_table[op].compat(
call->args[0], call->args[1], call->args[2],
call->args[3], call->args[4], call->args[5]);
else
call->result = -ENOSYS;
}
-#ifdef CONFIG_PV32
else
+#endif
{
- struct compat_multicall_entry *call = &state->compat_call;
+ struct multicall_entry *call = &state->call;
op = call->op;
if ( (op < ARRAY_SIZE(pv_hypercall_table)) &&
- pv_hypercall_table[op].compat )
- call->result = pv_hypercall_table[op].compat(
+ pv_hypercall_table[op].native )
+ call->result = pv_hypercall_table[op].native(
call->args[0], call->args[1], call->args[2],
call->args[3], call->args[4], call->args[5]);
else
call->result = -ENOSYS;
}
-#endif
return unlikely(op == __HYPERVISOR_iret)
? mc_exit
--
2.30.1
next prev parent reply other threads:[~2021-04-23 9:44 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-23 9:43 [PATCH 0/2] x86/clang: build fixes Roger Pau Monne
2021-04-23 9:43 ` [PATCH 1/2] x86/oprofile: fix oprofile for clang build Roger Pau Monne
2021-04-23 9:45 ` Jan Beulich
2021-04-23 9:43 ` Roger Pau Monne [this message]
2021-04-23 9:46 ` [PATCH 2/2] x86/pv: fix clang build without CONFIG_PV32 Roger Pau Monné
2021-04-23 9:48 ` Jan Beulich
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