um: Add support for host CPU flags and alignment

1. Reflect host cpu flags into the UML instance so they can
be used to select the correct implementations for xor, crypto, etc.

2. Reflect host cache alignment into UML instance. This is
important when running 32 bit on a 64 bit host as 32 bit by
default aligns to 32 while the actual alignment should be 64.
Ditto for some Xeons which align at 128.

Signed-off-by: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Signed-off-by: Richard Weinberger <richard@nod.at>

1 files changed, 44 insertions, 4 deletions

diff --git a/arch/um/kernel/um_arch.c b/arch/um/kernel/um_arch.c
index 74e07e748a9b..20cce10bde51 100644
--- a/arch/um/kernel/um_arch.c
+++ b/arch/um/kernel/um_arch.c
@@ -6,6 +6,7 @@
 #include <linux/delay.h>
 #include <linux/init.h>
 #include <linux/mm.h>
+#include <linux/ctype.h>
 #include <linux/module.h>
 #include <linux/seq_file.h>
 #include <linux/string.h>
@@ -16,6 +17,7 @@
 #include <linux/suspend.h>
 
 #include <asm/processor.h>
+#include <asm/cpufeature.h>
 #include <asm/sections.h>
 #include <asm/setup.h>
 #include <as-layout.h>
@@ -50,9 +52,13 @@ static void __init add_arg(char *arg)
  */
 struct cpuinfo_um boot_cpu_data = {
 	.loops_per_jiffy	= 0,
-	.ipi_pipe		= { -1, -1 }
+	.ipi_pipe		= { -1, -1 },
+	.cache_alignment	= L1_CACHE_BYTES,
+	.x86_capability		= { 0 }
 };
 
+EXPORT_SYMBOL(boot_cpu_data);
+
 union thread_union cpu0_irqstack
 	__section(".data..init_irqstack") =
 		{ .thread_info = INIT_THREAD_INFO(init_task) };
@@ -62,17 +68,25 @@ static char host_info[(__NEW_UTS_LEN + 1) * 5];
 
 static int show_cpuinfo(struct seq_file *m, void *v)
 {
-	int index = 0;
+	int i = 0;
 
-	seq_printf(m, "processor\t: %d\n", index);
+	seq_printf(m, "processor\t: %d\n", i);
 	seq_printf(m, "vendor_id\t: User Mode Linux\n");
 	seq_printf(m, "model name\t: UML\n");
 	seq_printf(m, "mode\t\t: skas\n");
 	seq_printf(m, "host\t\t: %s\n", host_info);
-	seq_printf(m, "bogomips\t: %lu.%02lu\n\n",
+	seq_printf(m, "fpu\t\t: %s\n", cpu_has(&boot_cpu_data, X86_FEATURE_FPU) ? "yes" : "no");
+	seq_printf(m, "flags\t\t:");
+	for (i = 0; i < 32*NCAPINTS; i++)
+		if (cpu_has(&boot_cpu_data, i) && (x86_cap_flags[i] != NULL))
+			seq_printf(m, " %s", x86_cap_flags[i]);
+	seq_printf(m, "\n");
+	seq_printf(m, "cache_alignment\t: %d\n", boot_cpu_data.cache_alignment);
+	seq_printf(m, "bogomips\t: %lu.%02lu\n",
 		   loops_per_jiffy/(500000/HZ),
 		   (loops_per_jiffy/(5000/HZ)) % 100);
 
+
 	return 0;
 }
 
@@ -261,6 +275,30 @@ EXPORT_SYMBOL(end_iomem);
 
 #define MIN_VMALLOC (32 * 1024 * 1024)
 
+static void parse_host_cpu_flags(char *line)
+{
+	int i;
+	for (i = 0; i < 32*NCAPINTS; i++) {
+		if ((x86_cap_flags[i] != NULL) && strstr(line, x86_cap_flags[i]))
+			set_cpu_cap(&boot_cpu_data, i);;
+	}
+}
+static void parse_cache_line(char *line)
+{
+	long res;
+	char *to_parse = strstr(line, ":");
+	if (to_parse) {
+		to_parse++;
+		while (*to_parse != 0 && isspace(*to_parse)) {
+			to_parse++;
+		}
+		if (kstrtoul(to_parse, 10, &res) == 0 && is_power_of_2(res))
+			boot_cpu_data.cache_alignment = res;
+		else
+			boot_cpu_data.cache_alignment = L1_CACHE_BYTES;
+	}
+}
+
 int __init linux_main(int argc, char **argv)
 {
 	unsigned long avail, diff;
@@ -297,6 +335,8 @@ int __init linux_main(int argc, char **argv)
 	/* OS sanity checks that need to happen before the kernel runs */
 	os_early_checks();
 
+	get_host_cpu_features(parse_host_cpu_flags, parse_cache_line);
+
 	brk_start = (unsigned long) sbrk(0);
 
 	/*