* [PATCH 0/2] x86/clang: build fixes
@ 2021-04-23 9:43 Roger Pau Monne
2021-04-23 9:43 ` [PATCH 1/2] x86/oprofile: fix oprofile for clang build Roger Pau Monne
2021-04-23 9:43 ` [PATCH 2/2] x86/pv: fix clang build without CONFIG_PV32 Roger Pau Monne
0 siblings, 2 replies; 6+ messages in thread
From: Roger Pau Monne @ 2021-04-23 9:43 UTC (permalink / raw)
To: xen-devel; +Cc: Roger Pau Monne, Jan Beulich, Andrew Cooper, Wei Liu
Hello,
Two clang related build fixes to get the hypervisor building again with
clang without CONFIG_PV32.
Thanks, Roger.
Roger Pau Monne (2):
x86/oprofile: fix oprofile for clang build
x86/pv: fix clang build without CONFIG_PV32
xen/arch/x86/oprofile/backtrace.c | 2 ++
xen/arch/x86/pv/hypercall.c | 18 +++++++++---------
2 files changed, 11 insertions(+), 9 deletions(-)
--
2.30.1
^ permalink raw reply [flat|nested] 6+ messages in thread
* [PATCH 1/2] x86/oprofile: fix oprofile for clang build
2021-04-23 9:43 [PATCH 0/2] x86/clang: build fixes Roger Pau Monne
@ 2021-04-23 9:43 ` Roger Pau Monne
2021-04-23 9:45 ` Jan Beulich
2021-04-23 9:43 ` [PATCH 2/2] x86/pv: fix clang build without CONFIG_PV32 Roger Pau Monne
1 sibling, 1 reply; 6+ messages in thread
From: Roger Pau Monne @ 2021-04-23 9:43 UTC (permalink / raw)
To: xen-devel; +Cc: Roger Pau Monne, Jan Beulich, Andrew Cooper, Wei Liu
Clang complains with:
backtrace.c:46:19: error: unused function 'is_32bit_vcpu' [-Werror,-Wunused-function]
static inline int is_32bit_vcpu(struct vcpu *vcpu)
^
Fix this by guarding the function with CONFIG_COMPAT, as it's only
caller is also doing so.
Fixes: d23d792478d ('x86: avoid building COMPAT code when !HVM && !PV32')
Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
---
xen/arch/x86/oprofile/backtrace.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/xen/arch/x86/oprofile/backtrace.c b/xen/arch/x86/oprofile/backtrace.c
index 929bf51a408..bd5d1b0f6ce 100644
--- a/xen/arch/x86/oprofile/backtrace.c
+++ b/xen/arch/x86/oprofile/backtrace.c
@@ -43,6 +43,7 @@ dump_hypervisor_backtrace(struct vcpu *vcpu, const struct frame_head *head,
return head->ebp;
}
+#ifdef CONFIG_COMPAT
static inline int is_32bit_vcpu(struct vcpu *vcpu)
{
if (is_hvm_vcpu(vcpu))
@@ -50,6 +51,7 @@ static inline int is_32bit_vcpu(struct vcpu *vcpu)
else
return is_pv_32bit_vcpu(vcpu);
}
+#endif
static struct frame_head *
dump_guest_backtrace(struct vcpu *vcpu, const struct frame_head *head,
--
2.30.1
^ permalink raw reply related [flat|nested] 6+ messages in thread* Re: [PATCH 1/2] x86/oprofile: fix oprofile for clang build
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
0 siblings, 0 replies; 6+ messages in thread
From: Jan Beulich @ 2021-04-23 9:45 UTC (permalink / raw)
To: Roger Pau Monne; +Cc: Andrew Cooper, Wei Liu, xen-devel
On 23.04.2021 11:43, Roger Pau Monne wrote:
> Clang complains with:
>
> backtrace.c:46:19: error: unused function 'is_32bit_vcpu' [-Werror,-Wunused-function]
> static inline int is_32bit_vcpu(struct vcpu *vcpu)
> ^
>
> Fix this by guarding the function with CONFIG_COMPAT, as it's only
> caller is also doing so.
>
> Fixes: d23d792478d ('x86: avoid building COMPAT code when !HVM && !PV32')
> Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
See my "x86/oprof: fix !HVM && !PV32 build" from the 16th.
Jan
^ permalink raw reply [flat|nested] 6+ messages in thread
* [PATCH 2/2] x86/pv: fix clang build without CONFIG_PV32
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 9:43 ` Roger Pau Monne
2021-04-23 9:46 ` Roger Pau Monné
2021-04-23 9:48 ` Jan Beulich
1 sibling, 2 replies; 6+ messages in thread
From: Roger Pau Monne @ 2021-04-23 9:43 UTC (permalink / raw)
To: xen-devel; +Cc: Roger Pau Monne, Jan Beulich, Andrew Cooper, Wei Liu
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
^ permalink raw reply related [flat|nested] 6+ messages in thread* Re: [PATCH 2/2] x86/pv: fix clang build without CONFIG_PV32
2021-04-23 9:43 ` [PATCH 2/2] x86/pv: fix clang build without CONFIG_PV32 Roger Pau Monne
@ 2021-04-23 9:46 ` Roger Pau Monné
2021-04-23 9:48 ` Jan Beulich
1 sibling, 0 replies; 6+ messages in thread
From: Roger Pau Monné @ 2021-04-23 9:46 UTC (permalink / raw)
To: xen-devel; +Cc: Jan Beulich, Andrew Cooper, Wei Liu
On Fri, Apr 23, 2021 at 11:43:43AM +0200, Roger Pau Monne wrote:
> Clang reports the following build error without CONFIG_PV:
s/CONFIG_PV/CONFIG_PV32/ on the line above, sorry.
Thanks, Roger.
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH 2/2] x86/pv: fix clang build without CONFIG_PV32
2021-04-23 9:43 ` [PATCH 2/2] x86/pv: fix clang build without CONFIG_PV32 Roger Pau Monne
2021-04-23 9:46 ` Roger Pau Monné
@ 2021-04-23 9:48 ` Jan Beulich
1 sibling, 0 replies; 6+ messages in thread
From: Jan Beulich @ 2021-04-23 9:48 UTC (permalink / raw)
To: Roger Pau Monne; +Cc: Andrew Cooper, Wei Liu, xen-devel
On 23.04.2021 11:43, Roger Pau Monne wrote:
> 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>
I find it odd for the compiler to warn like this, but well ...
Acked-by: Jan Beulich <jbeulich@suse.com>
> Should the is_pv_32bit_vcpu be wrapped in an unlikely hint?
Not sure. Andrew did some similar rearrangement elsewhere for
other reasons, without adding unlikely(). Personally I think
we'd better add them, but then preferably add consistently as
possible.
Jan
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2021-04-23 9:49 UTC | newest]
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2021-04-23 9:45 ` Jan Beulich
2021-04-23 9:43 ` [PATCH 2/2] x86/pv: fix clang build without CONFIG_PV32 Roger Pau Monne
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