[PATCH 077/208] x86/fpu: Improve FPU detection kernel messages

Ingo Molnar
2015-05-05T16:30:03Z

Standardize the various boot time messages printed during FPU detection:

- Use a common 'x86/fpu: ' prefix for consistency and to make it easy
to grep boot logs for FPU related messages

- Correct speling errors

- Add printout for the legacy FPU case as well

- Clarify messages

Reviewed-by: Borislav Petkov <bp@alien8.de>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
arch/x86/kernel/fpu/xsave.c | 26 ++++++++++++++------------
1 file changed, 14 insertions(+), 12 deletions(-)

diff --git a/arch/x86/kernel/fpu/xsave.c b/arch/x86/kernel/fpu/xsave.c
index 6c1cbb2487fe..bfe92f73bf86 100644
--- a/arch/x86/kernel/fpu/xsave.c
+++ b/arch/x86/kernel/fpu/xsave.c
@@ -3,9 +3,6 @@
*
* Author: Suresh Siddha <suresh.b.siddha@intel.com>
*/
-
-#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
-
#include <linux/bootmem.h>
#include <linux/compat.h>
#include <linux/cpu.h>
@@ -615,7 +612,7 @@ static void /* __init */ xstate_enable_boot_cpu(void)
unsigned int eax, ebx, ecx, edx;

if (boot_cpu_data.cpuid_level < XSTATE_CPUID) {
- WARN(1, KERN_ERR "XSTATE_CPUID missing\n");
+ WARN(1, "x86/fpu: XSTATE_CPUID missing!\n");
return;
}

@@ -623,8 +620,7 @@ static void /* __init */ xstate_enable_boot_cpu(void)
pcntxt_mask = eax + ((u64)edx << 32);

if ((pcntxt_mask & XSTATE_FPSSE) != XSTATE_FPSSE) {
- pr_err("FP/SSE not shown under xsave features 0x%llx\n",
- pcntxt_mask);
+ pr_err("x86/fpu: FP/SSE not present amongst the CPU's xstate features: 0x%llx.\n", pcntxt_mask);
BUG();
}

@@ -650,17 +646,18 @@ static void /* __init */ xstate_enable_boot_cpu(void)

if (pcntxt_mask & XSTATE_EAGER) {
if (eagerfpu == DISABLE) {
- pr_err("eagerfpu not present, disabling some xstate features: 0x%llx\n",
- pcntxt_mask & XSTATE_EAGER);
+ pr_err("x86/fpu: eagerfpu switching disabled, disabling the following xstate features: 0x%llx.\n",
+ pcntxt_mask & XSTATE_EAGER);
pcntxt_mask &= ~XSTATE_EAGER;
} else {
eagerfpu = ENABLE;
}
}

- pr_info("enabled xstate_bv 0x%llx, cntxt size 0x%x using %s\n",
- pcntxt_mask, xstate_size,
- cpu_has_xsaves ? "compacted form" : "standard form");
+ pr_info("x86/fpu: Enabled xstate features 0x%llx, context size is 0x%x bytes, using '%s' format.\n",
+ pcntxt_mask,
+ xstate_size,
+ cpu_has_xsaves ? "compacted" : "standard");
}

/*
@@ -671,8 +668,13 @@ void xsave_init(void)
{
static char on_boot_cpu = 1;

- if (!cpu_has_xsave)
+ if (!cpu_has_xsave) {
+ if (on_boot_cpu) {
+ on_boot_cpu = 0;
+ pr_info("x86/fpu: Legacy x87 FPU detected.\n");
+ }
return;
+ }

if (on_boot_cpu) {
on_boot_cpu = 0;
--
2.1.0