[PATCH] x86: avoid pointless fields of struct cpuinfo_x86
From: Jan Beulich
Date: Wed Apr 27 2011 - 11:06:16 EST
Several of the flag fields of this structure are completely unused in
certain (common) configurations. Don't pointlessly reserve space for
them, and have truly flag-only fields consume a single bit only.
Make functionality detection conditional upon (partly new) config
options that are now also used to control the presence of those
fields.
Signed-off-by: Jan Beulich <jbeulich@xxxxxxxxxx>
---
arch/x86/Kconfig.cpu | 16 +++++++++-
arch/x86/include/asm/processor.h | 58 ++++++++++++++++++++++++++++-----------
arch/x86/kernel/asm-offsets_32.c | 2 +
arch/x86/kernel/cpu/bugs.c | 26 ++++++++++++-----
arch/x86/kernel/cpu/cyrix.c | 2 -
arch/x86/kernel/cpu/proc.c | 47 ++++++++++++++++---------------
arch/x86/kernel/head_32.S | 2 +
arch/x86/kernel/i387.c | 2 -
arch/x86/kernel/irqinit.c | 4 +-
arch/x86/kernel/process.c | 4 +-
arch/x86/kernel/setup.c | 24 ++++++++++++++--
arch/x86/lguest/boot.c | 4 ++
arch/x86/lib/usercopy_32.c | 2 -
arch/x86/mm/init_32.c | 9 ++++--
arch/x86/xen/enlighten.c | 6 ++--
arch/x86/xen/setup.c | 4 +-
16 files changed, 148 insertions(+), 64 deletions(-)
--- 2.6.39-rc5/arch/x86/Kconfig.cpu
+++ 2.6.39-rc5-i386-cpuinfo-pack/arch/x86/Kconfig.cpu
@@ -302,6 +302,10 @@ config X86_INTERNODE_CACHE_SHIFT
default "7" if NUMA
default X86_L1_CACHE_SHIFT
+config X86_FPU
+ def_bool y
+ depends on !M386 && !M486 && !MATH_EMULATION
+
config X86_CMPXCHG
def_bool X86_64 || (X86_32 && !M386)
@@ -334,11 +338,19 @@ config X86_PPRO_FENCE
config X86_F00F_BUG
def_bool y
- depends on M586MMX || M586TSC || M586 || M486 || M386
+ depends on CPU_SUP_INTEL && (M586MMX || M586TSC || M586 || M486 || M386)
+
+config X86_FDIV_BUG
+ def_bool y
+ depends on CPU_SUP_INTEL && (M586TSC || M586 || M486 || M386)
config X86_INVD_BUG
def_bool y
- depends on M486 || M386
+ depends on CPU_SUP_AMD && (M486 || M386)
+
+config X86_HLT_WORKS_OK
+ def_bool y
+ depends on !M386 && !M486
config X86_WP_WORKS_OK
def_bool y
--- 2.6.39-rc5/arch/x86/include/asm/processor.h
+++ 2.6.39-rc5-i386-cpuinfo-pack/arch/x86/include/asm/processor.h
@@ -63,18 +63,26 @@ struct cpuinfo_x86 {
__u8 x86_vendor; /* CPU vendor */
__u8 x86_model;
__u8 x86_mask;
-#ifdef CONFIG_X86_32
- char wp_works_ok; /* It doesn't on 386's */
-
+#ifndef CONFIG_X86_FPU
+ bool hard_math;
+#endif
+#ifndef CONFIG_X86_WP_WORKS_OK
+ bool wp_works_ok:1; /* It doesn't on 386's */
+#endif
+#ifndef CONFIG_X86_HLT_WORKS_OK
/* Problems on some 486Dx4's and old 386's: */
- char hlt_works_ok;
- char hard_math;
- char rfu;
- char fdiv_bug;
- char f00f_bug;
- char coma_bug;
- char pad0;
-#else
+ bool hlt_works_ok:1;
+#endif
+#ifdef CONFIG_X86_FDIV_BUG
+ bool fdiv_bug:1;
+#endif
+#ifdef CONFIG_X86_F00F_BUG
+ bool f00f_bug:1;
+#endif
+#ifdef CONFIG_CPU_SUP_CYRIX_32
+ bool coma_bug:1;
+#endif
+#ifdef CONFIG_X86_64
/* Number of 4K pages in DTLB/ITLB combined(in pages): */
int x86_tlbsize;
#endif
@@ -144,12 +152,32 @@ DECLARE_PER_CPU_SHARED_ALIGNED(struct cp
extern const struct seq_operations cpuinfo_op;
-static inline int hlt_works(int cpu)
+static inline bool hard_math(const struct cpuinfo_x86 *c)
{
-#ifdef CONFIG_X86_32
- return cpu_data(cpu).hlt_works_ok;
+#ifndef CONFIG_X86_FPU
+ return c->hard_math;
+#else
+ return true;
+#endif
+}
+
+extern bool wp_works_ok; /* set to true to skip check */
+
+static inline bool wp_works(const struct cpuinfo_x86 *c)
+{
+#ifndef CONFIG_X86_WP_WORKS_OK
+ return c->wp_works_ok;
+#else
+ return true;
+#endif
+}
+
+static inline bool hlt_works(const struct cpuinfo_x86 *c)
+{
+#ifndef CONFIG_X86_HLT_WORKS_OK
+ return c->hlt_works_ok;
#else
- return 1;
+ return true;
#endif
}
--- 2.6.39-rc5/arch/x86/kernel/asm-offsets_32.c
+++ 2.6.39-rc5-i386-cpuinfo-pack/arch/x86/kernel/asm-offsets_32.c
@@ -23,7 +23,9 @@ void foo(void)
OFFSET(CPUINFO_x86_vendor, cpuinfo_x86, x86_vendor);
OFFSET(CPUINFO_x86_model, cpuinfo_x86, x86_model);
OFFSET(CPUINFO_x86_mask, cpuinfo_x86, x86_mask);
+#ifndef CONFIG_X86_FPU
OFFSET(CPUINFO_hard_math, cpuinfo_x86, hard_math);
+#endif
OFFSET(CPUINFO_cpuid_level, cpuinfo_x86, cpuid_level);
OFFSET(CPUINFO_x86_capability, cpuinfo_x86, x86_capability);
OFFSET(CPUINFO_x86_vendor_id, cpuinfo_x86, x86_vendor_id);
--- 2.6.39-rc5/arch/x86/kernel/cpu/bugs.c
+++ 2.6.39-rc5-i386-cpuinfo-pack/arch/x86/kernel/cpu/bugs.c
@@ -17,25 +17,24 @@
#include <asm/paravirt.h>
#include <asm/alternative.h>
+#ifndef CONFIG_X86_HLT_WORKS_OK
static int __init no_halt(char *s)
{
boot_cpu_data.hlt_works_ok = 0;
return 1;
}
-
__setup("no-hlt", no_halt);
+#endif
+#ifndef CONFIG_X86_FPU
static int __init no_387(char *s)
{
boot_cpu_data.hard_math = 0;
write_cr0(X86_CR0_TS | X86_CR0_EM | X86_CR0_MP | read_cr0());
return 1;
}
-
__setup("no387", no_387);
-
-static double __initdata x = 4195835.0;
-static double __initdata y = 3145727.0;
+#endif
/*
* This used to check for exceptions..
@@ -50,8 +49,10 @@ static double __initdata y = 3145727.0;
*/
static void __init check_fpu(void)
{
- s32 fdiv_bug;
-
+#ifdef CONFIG_X86_FPU
+ if (!cpu_has_fpu)
+ panic("No coprocessor found.\n");
+#else
if (!boot_cpu_data.hard_math) {
#ifndef CONFIG_MATH_EMULATION
printk(KERN_EMERG "No coprocessor found and no math emulation present.\n");
@@ -60,6 +61,13 @@ static void __init check_fpu(void)
#endif
return;
}
+#endif
+
+#ifdef CONFIG_X86_FDIV_BUG
+ {
+ s32 fdiv_bug;
+ static const double __initconst x = 4195835.0;
+ static const double __initconst y = 3145727.0;
/*
* trap_init() enabled FXSR and company _before_ testing for FP
@@ -82,10 +90,13 @@ static void __init check_fpu(void)
boot_cpu_data.fdiv_bug = fdiv_bug;
if (boot_cpu_data.fdiv_bug)
printk(KERN_WARNING "Hmm, FPU with FDIV bug.\n");
+ }
+#endif
}
static void __init check_hlt(void)
{
+#ifndef CONFIG_X86_HLT_WORKS_OK
if (boot_cpu_data.x86 >= 5 || paravirt_enabled())
return;
@@ -99,6 +110,7 @@ static void __init check_hlt(void)
halt();
halt();
printk(KERN_CONT "OK.\n");
+#endif
}
/*
--- 2.6.39-rc5/arch/x86/kernel/cpu/cyrix.c
+++ 2.6.39-rc5-i386-cpuinfo-pack/arch/x86/kernel/cpu/cyrix.c
@@ -332,7 +332,7 @@ static void __cpuinit init_cyrix(struct
switch (dir0_lsn) {
case 0xd: /* either a 486SLC or DLC w/o DEVID */
dir0_msn = 0;
- p = Cx486_name[(c->hard_math) ? 1 : 0];
+ p = Cx486_name[hard_math(c)];
break;
case 0xe: /* a 486S A step */
--- 2.6.39-rc5/arch/x86/kernel/cpu/proc.c
+++ 2.6.39-rc5-i386-cpuinfo-pack/arch/x86/kernel/cpu/proc.c
@@ -23,43 +23,44 @@ static void show_cpuinfo_core(struct seq
#endif
}
-#ifdef CONFIG_X86_32
static void show_cpuinfo_misc(struct seq_file *m, struct cpuinfo_x86 *c)
{
+#ifdef CONFIG_X86_32
/*
* We use exception 16 if we have hardware math and we've either seen
* it or the CPU claims it is internal
*/
- int fpu_exception = c->hard_math && (ignore_fpu_irq || cpu_has_fpu);
+ bool fpu_exception = hard_math(c) && (ignore_fpu_irq || cpu_has_fpu);
+#else
+ bool fpu_exception = true;
+#endif
+
+#ifdef CONFIG_X86_FDIV_BUG
+ seq_printf(m, "fdiv_bug\t: %s\n", c->fdiv_bug ? "yes" : "no");
+#endif
+
+#ifndef CONFIG_X86_HLT_WORKS_OK
+ seq_printf(m, "hlt_bug\t\t: %s\n", c->hlt_works_ok ? "no" : "yes");
+#endif
+
+#ifdef CONFIG_X86_F00F_BUG
+ seq_printf(m, "f00f_bug\t: %s\n", c->f00f_bug ? "yes" : "no");
+#endif
+
+#ifdef CONFIG_CPU_SUP_CYRIX_32
+ seq_printf(m, "coma_bug\t: %s\n", c->coma_bug ? "yes" : "no");
+#endif
+
seq_printf(m,
- "fdiv_bug\t: %s\n"
- "hlt_bug\t\t: %s\n"
- "f00f_bug\t: %s\n"
- "coma_bug\t: %s\n"
"fpu\t\t: %s\n"
"fpu_exception\t: %s\n"
"cpuid level\t: %d\n"
"wp\t\t: %s\n",
- c->fdiv_bug ? "yes" : "no",
- c->hlt_works_ok ? "no" : "yes",
- c->f00f_bug ? "yes" : "no",
- c->coma_bug ? "yes" : "no",
- c->hard_math ? "yes" : "no",
+ hard_math(c) ? "yes" : "no",
fpu_exception ? "yes" : "no",
c->cpuid_level,
- c->wp_works_ok ? "yes" : "no");
-}
-#else
-static void show_cpuinfo_misc(struct seq_file *m, struct cpuinfo_x86 *c)
-{
- seq_printf(m,
- "fpu\t\t: yes\n"
- "fpu_exception\t: yes\n"
- "cpuid level\t: %d\n"
- "wp\t\t: yes\n",
- c->cpuid_level);
+ wp_works(c) ? "yes" : "no");
}
-#endif
static int show_cpuinfo(struct seq_file *m, void *v)
{
--- 2.6.39-rc5/arch/x86/kernel/head_32.S
+++ 2.6.39-rc5-i386-cpuinfo-pack/arch/x86/kernel/head_32.S
@@ -480,6 +480,7 @@ is386: movl $2,%ecx # set MP
* We depend on ET to be correct. This checks for 287/387.
*/
check_x87:
+#ifndef CONFIG_X86_FPU
movb $0,X86_HARD_MATH
clts
fninit
@@ -493,6 +494,7 @@ check_x87:
ALIGN
1: movb $1,X86_HARD_MATH
.byte 0xDB,0xE4 /* fsetpm for 287, ignored by 387 */
+#endif
ret
/*
--- 2.6.39-rc5/arch/x86/kernel/i387.c
+++ 2.6.39-rc5-i386-cpuinfo-pack/arch/x86/kernel/i387.c
@@ -33,7 +33,7 @@
#endif
#ifdef CONFIG_MATH_EMULATION
-# define HAVE_HWFP (boot_cpu_data.hard_math)
+# define HAVE_HWFP hard_math(&boot_cpu_data)
#else
# define HAVE_HWFP 1
#endif
--- 2.6.39-rc5/arch/x86/kernel/irqinit.c
+++ 2.6.39-rc5-i386-cpuinfo-pack/arch/x86/kernel/irqinit.c
@@ -59,7 +59,7 @@
static irqreturn_t math_error_irq(int cpl, void *dev_id)
{
outb(0, 0xF0);
- if (ignore_fpu_irq || !boot_cpu_data.hard_math)
+ if (ignore_fpu_irq || !hard_math(&boot_cpu_data))
return IRQ_NONE;
math_error(get_irq_regs(), 0, 16);
return IRQ_HANDLED;
@@ -323,7 +323,7 @@ void __init native_init_IRQ(void)
* External FPU? Set up irq13 if so, for
* original braindamaged IBM FERR coupling.
*/
- if (boot_cpu_data.hard_math && !cpu_has_fpu)
+ if (hard_math(&boot_cpu_data) && !cpu_has_fpu)
setup_irq(FPU_IRQ, &fpu_irq);
irq_ctx_init(smp_processor_id());
--- 2.6.39-rc5/arch/x86/kernel/process.c
+++ 2.6.39-rc5-i386-cpuinfo-pack/arch/x86/kernel/process.c
@@ -359,7 +359,7 @@ EXPORT_SYMBOL(enable_hlt);
static inline int hlt_use_halt(void)
{
- return (!hlt_counter && boot_cpu_data.hlt_works_ok);
+ return (!hlt_counter && hlt_works(&boot_cpu_data));
}
#else
static inline int hlt_use_halt(void)
@@ -411,7 +411,7 @@ void stop_this_cpu(void *dummy)
disable_local_APIC();
for (;;) {
- if (hlt_works(smp_processor_id()))
+ if (hlt_works(&cpu_data(smp_processor_id())))
halt();
}
}
--- 2.6.39-rc5/arch/x86/kernel/setup.c
+++ 2.6.39-rc5-i386-cpuinfo-pack/arch/x86/kernel/setup.c
@@ -176,9 +176,29 @@ static struct resource bss_resource = {
#ifdef CONFIG_X86_32
/* cpu data as detected by the assembly code in head.S */
-struct cpuinfo_x86 new_cpu_data __cpuinitdata = {0, 0, 0, 0, -1, 1, 0, 0, -1};
+struct cpuinfo_x86 new_cpu_data __cpuinitdata = {
+# ifndef CONFIG_X86_WP_WORKS_OK
+ .wp_works_ok = true,
+# endif
+# ifndef CONFIG_X86_HLT_WORKS_OK
+ .hlt_works_ok = true,
+# endif
+# ifdef CONFIG_X86_FDIV_BUG
+ .fdiv_bug = true,
+# endif
+};
/* common cpu data for all cpus */
-struct cpuinfo_x86 boot_cpu_data __read_mostly = {0, 0, 0, 0, -1, 1, 0, 0, -1};
+struct cpuinfo_x86 boot_cpu_data __read_mostly = {
+# ifndef CONFIG_X86_WP_WORKS_OK
+ .wp_works_ok = true,
+# endif
+# ifndef CONFIG_X86_HLT_WORKS_OK
+ .hlt_works_ok = true,
+# endif
+# ifdef CONFIG_X86_FDIV_BUG
+ .fdiv_bug = true,
+# endif
+};
EXPORT_SYMBOL(boot_cpu_data);
static void set_mca_bus(int x)
{
--- 2.6.39-rc5/arch/x86/lguest/boot.c
+++ 2.6.39-rc5-i386-cpuinfo-pack/arch/x86/lguest/boot.c
@@ -1384,8 +1384,10 @@ __init void lguest_init(void)
/* head.S usually sets up the first capability word, so do it here. */
new_cpu_data.x86_capability[0] = cpuid_edx(1);
+#ifndef CONFIG_X86_FPU
/* Math is always hard! */
- new_cpu_data.hard_math = 1;
+ new_cpu_data.hard_math = true;
+#endif
/* We don't have features. We have puppies! Puppies! */
#ifdef CONFIG_X86_MCE
--- 2.6.39-rc5/arch/x86/lib/usercopy_32.c
+++ 2.6.39-rc5-i386-cpuinfo-pack/arch/x86/lib/usercopy_32.c
@@ -718,7 +718,7 @@ unsigned long __copy_to_user_ll(void __u
unsigned long n)
{
#ifndef CONFIG_X86_WP_WORKS_OK
- if (unlikely(boot_cpu_data.wp_works_ok == 0) &&
+ if (unlikely(!wp_works(&boot_cpu_data)) &&
((unsigned long)to) < TASK_SIZE) {
/*
* When we are in an atomic section (see
--- 2.6.39-rc5/arch/x86/mm/init_32.c
+++ 2.6.39-rc5-i386-cpuinfo-pack/arch/x86/mm/init_32.c
@@ -56,6 +56,7 @@
unsigned long highstart_pfn, highend_pfn;
+bool __initdata wp_works_ok;
static noinline int do_test_wp_bit(void);
bool __read_mostly __vmalloc_start_set = false;
@@ -733,14 +734,16 @@ static void __init test_wp_bit(void)
/* Any page-aligned address will do, the test is non-destructive */
__set_fixmap(FIX_WP_TEST, __pa(&swapper_pg_dir), PAGE_READONLY);
- boot_cpu_data.wp_works_ok = do_test_wp_bit();
+ wp_works_ok = do_test_wp_bit();
clear_fixmap(FIX_WP_TEST);
- if (!boot_cpu_data.wp_works_ok) {
+ if (!wp_works_ok) {
printk(KERN_CONT "No.\n");
#ifdef CONFIG_X86_WP_WORKS_OK
panic(
"This kernel doesn't support CPU's with broken WP. Recompile it for a 386!");
+#else
+ boot_cpu_data.wp_works_ok = false;
#endif
} else {
printk(KERN_CONT "Ok.\n");
@@ -839,7 +842,7 @@ void __init mem_init(void)
BUG_ON(VMALLOC_START >= VMALLOC_END);
BUG_ON((unsigned long)high_memory > VMALLOC_START);
- if (boot_cpu_data.wp_works_ok < 0)
+ if (!wp_works_ok)
test_wp_bit();
}
--- 2.6.39-rc5/arch/x86/xen/enlighten.c
+++ 2.6.39-rc5-i386-cpuinfo-pack/arch/x86/xen/enlighten.c
@@ -1222,8 +1222,10 @@ asmlinkage void __init xen_start_kernel(
#ifdef CONFIG_X86_32
/* set up basic CPUID stuff */
cpu_detect(&new_cpu_data);
- new_cpu_data.hard_math = 1;
- new_cpu_data.wp_works_ok = 1;
+# ifndef CONFIG_X86_FPU
+ new_cpu_data.hard_math = true;
+# endif
+ wp_works_ok = true;
new_cpu_data.x86_capability[0] = cpuid_edx(1);
#endif
--- 2.6.39-rc5/arch/x86/xen/setup.c
+++ 2.6.39-rc5-i386-cpuinfo-pack/arch/x86/xen/setup.c
@@ -417,8 +417,8 @@ void __init xen_arch_setup(void)
COMMAND_LINE_SIZE : MAX_GUEST_CMDLINE);
/* Set up idle, making sure it calls safe_halt() pvop */
-#ifdef CONFIG_X86_32
- boot_cpu_data.hlt_works_ok = 1;
+#ifndef CONFIG_X86_HLT_WORKS_OK
+ boot_cpu_data.hlt_works_ok = true;
#endif
pm_idle = default_idle;
boot_option_idle_override = IDLE_HALT;
--
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