Re: linux-next: parsing mem=700M broken

Rusty Russell
2008-12-25T11:40:52Z

On Wednesday 24 December 2008 18:39:04 Yinghai Lu wrote:
> for cpu caps on boot cpu setup still need

OK, how about these? I cleaned up description a little, and put
it in own function.

Subject: [PATCH] x86: clean up setup_clear/force_cpu_cap handling
From: Yinghai Lu <yinghai.lu@kernel.org>

Impact: fix and cleanup

setup_force_cpu_cap() only has one user (xen) but it should not reuse
cleared_cpu_cpus. It will have problems for smp.

Need to have cpu_cpus_set array too, and need to combine it before
we AND into boot_cpu_data.x86_capability.

Signed-off-by: Yinghai Lu <yinghai.lu@kernel.org>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
---
arch/x86/include/asm/cpufeature.h | 4 ++--
arch/x86/include/asm/processor.h | 3 ++-
arch/x86/kernel/cpu/common.c | 17 ++++++++++++-----
3 files changed, 16 insertions(+), 8 deletions(-)

diff --git a/arch/x86/include/asm/cpufeature.h b/arch/x86/include/asm/cpufeature.h
--- a/arch/x86/include/asm/cpufeature.h
+++ b/arch/x86/include/asm/cpufeature.h
@@ -188,11 +188,11 @@ extern const char * const x86_power_flag
#define clear_cpu_cap(c, bit) clear_bit(bit, (unsigned long *)((c)->x86_capability))
#define setup_clear_cpu_cap(bit) do { \
clear_cpu_cap(&boot_cpu_data, bit); \
- set_bit(bit, (unsigned long *)cleared_cpu_caps); \
+ set_bit(bit, (unsigned long *)cpu_caps_cleared); \
} while (0)
#define setup_force_cpu_cap(bit) do { \
set_cpu_cap(&boot_cpu_data, bit); \
- clear_bit(bit, (unsigned long *)cleared_cpu_caps); \
+ set_bit(bit, (unsigned long *)cpu_caps_set); \
} while (0)

#define cpu_has_fpu boot_cpu_has(X86_FEATURE_FPU)
diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -130,7 +130,8 @@ extern struct cpuinfo_x86 new_cpu_data;
extern struct cpuinfo_x86 new_cpu_data;

extern struct tss_struct doublefault_tss;
-extern __u32 cleared_cpu_caps[NCAPINTS];
+extern __u32 cpu_caps_cleared[NCAPINTS];
+extern __u32 cpu_caps_set[NCAPINTS];

#ifdef CONFIG_SMP
DECLARE_PER_CPU(struct cpuinfo_x86, cpu_info);
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -219,7 +219,8 @@ static char __cpuinit *table_lookup_mode
return NULL; /* Not found */
}

-__u32 cleared_cpu_caps[NCAPINTS] __cpuinitdata;
+__u32 cpu_caps_cleared[NCAPINTS] __cpuinitdata;
+__u32 cpu_caps_set[NCAPINTS] __cpuinitdata;

/* Current gdt points %fs at the "master" per-cpu area: after this,
* it's on the real one. */
@@ -512,6 +513,16 @@ static void __cpuinit identify_cpu_witho
#endif
}

+static void __cpuinit override_capabilities(u32 x86_capability[])
+{
+ unsigned int i;
+
+ for (i = 0; i < NCAPINTS; i++) {
+ x86_capability[i] &= ~cpu_caps_cleared[i];
+ x86_capability[i] |= cpu_caps_set[i];
+ }
+}
+
/*
* Do minimum CPU detection early.
* Fields really needed: vendor, cpuid_level, family, model, mask,
@@ -703,6 +714,9 @@ static void __cpuinit identify_cpu(struc
detect_ht(c);
#endif

+ /* Command-line override before we AND into smp all cpus cap. */
+ override_capabilities(c->x86_capability);
+
/*
* On SMP, boot_cpu_data holds the common feature set between
* all CPUs; so make sure that we indicate which features are
@@ -714,10 +728,6 @@ static void __cpuinit identify_cpu(struc
for (i = 0; i < NCAPINTS; i++)
boot_cpu_data.x86_capability[i] &= c->x86_capability[i];
}
-
- /* Clear all flags overriden by options */
- for (i = 0; i < NCAPINTS; i++)
- c->x86_capability[i] &= ~cleared_cpu_caps[i];

#ifdef CONFIG_X86_MCE
/* Init Machine Check Exception if available. */

Subject: x86: override_capabilities in early_identify_cpu
From: Rusty Russell <rusty@rustcorp.com.au>

Impact: future-proof

This does nothing at the moment, but once early_param() are parsed before
setup_arch, it will ensure we respect commandline overrides on the boot
cpu's capabilities.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: Yinghai Lu <yinghai.lu@kernel.org>

diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -559,6 +559,8 @@ static void __init early_identify_cpu(st

if (this_cpu->c_early_init)
this_cpu->c_early_init(c);
+
+ override_capabilities(c->x86_capability);

validate_pat_support(c);