[PATCH] x86: vsmp: avoid link error with gcc -Og

[PATCH] x86: vsmp: avoid link error with gcc -Og

[Arnd Bergmann]

When the compiler skips optimizations for ease of debugging,
teh vsmp_cap_cpus() function is not eliminated from the build
with CONFIG_PCI=n:

arch/x86/kernel/vsmp_64.o: In function `vsmp_cap_cpus':
vsmp_64.c:(.init.text+0x23): undefined reference to `read_pci_config'

Change the caller in a way that will always optimize this
as required.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 arch/x86/kernel/vsmp_64.c | 10 ++++------
 1 file changed, 4 insertions(+), 6 deletions(-)

diff --git a/arch/x86/kernel/vsmp_64.c b/arch/x86/kernel/vsmp_64.c
index 1eae5af491c2..6a2ae6964ce5 100644
--- a/arch/x86/kernel/vsmp_64.c
+++ b/arch/x86/kernel/vsmp_64.c
@@ -146,8 +146,10 @@ static void __init detect_vsmp_box(void)
 		is_vsmp = 1;
 }
 
-static int is_vsmp_box(void)
+static int __init is_vsmp_box(void)
 {
+	detect_vsmp_box();
+
 	if (is_vsmp != -1)
 		return is_vsmp;
 	else {
@@ -157,10 +159,7 @@ static int is_vsmp_box(void)
 }
 
 #else
-static void __init detect_vsmp_box(void)
-{
-}
-static int is_vsmp_box(void)
+static __always_inline int is_vsmp_box(void)
 {
 	return 0;
 }
@@ -213,7 +212,6 @@ static void vsmp_apic_post_init(void)
 
 void __init vsmp_init(void)
 {
-	detect_vsmp_box();
 	if (!is_vsmp_box())
 		return;
 
-- 
2.18.0

Re: [PATCH] x86: vsmp: avoid link error with gcc -Og

[Thomas Gleixner]

Arnd,

On Fri, 2 Nov 2018, Arnd Bergmann wrote:

> When the compiler skips optimizations for ease of debugging,
> teh vsmp_cap_cpus() function is not eliminated from the build
> with CONFIG_PCI=n:

thanks for that, but the code has other issues, which are addressed with
this:

  https://lkml.kernel.org/r/1541404864-31603-1-git-send-email-eial@scalemp.com

That should also solve the problem you've observed.

Thanks,

	tglx

Re: [PATCH] x86: vsmp: avoid link error with gcc -Og

[Arnd Bergmann]

On 11/5/18, Thomas Gleixner <tglx@linutronix.de> wrote:
> Arnd,
>
> On Fri, 2 Nov 2018, Arnd Bergmann wrote:
>
>> When the compiler skips optimizations for ease of debugging,
>> teh vsmp_cap_cpus() function is not eliminated from the build
>> with CONFIG_PCI=n:
>
> thanks for that, but the code has other issues, which are addressed with
> this:
>
>
> https://lkml.kernel.org/r/1541404864-31603-1-git-send-email-eial@scalemp.com
>
> That should also solve the problem you've observed.

Ok, I've dropped my patch from my test tree, will let you know if
I see any other issues with the new patch applied.

      Arnd