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Subject[RFC PATCH 02/10] alpha: Notice if we're being run under QEMU
Date
When building a generic kernel, do a run-time check on the serial
number, like we do for MILO. When building a custom kernel, make
this a configure-time check.

Signed-off-by: Richard Henderson <rth@twiddle.net>
---
arch/alpha/Kconfig | 14 ++++++++++++++
arch/alpha/include/asm/machvec.h | 18 ++++++++++++------
arch/alpha/kernel/setup.c | 13 ++++++++++++-
3 files changed, 38 insertions(+), 7 deletions(-)

diff --git a/arch/alpha/Kconfig b/arch/alpha/Kconfig
index 082d9b4..2053f215 100644
--- a/arch/alpha/Kconfig
+++ b/arch/alpha/Kconfig
@@ -488,6 +488,20 @@ config VGA_HOSE
which always have multiple hoses, and whose consoles support it.


+config ALPHA_QEMU
+ bool "Run under QEMU emulation"
+ depends on !ALPHA_GENERIC
+ ---help---
+ Assume the presence of special features supported by QEMU PALcode
+ that reduce the overhead of system emulation.
+
+ Generic kernels will auto-detect QEMU. But when building a
+ system-specific kernel, the assumption is that we want to
+ elimiate as many runtime tests as possible.
+
+ If unsure, say N.
+
+
config ALPHA_SRM
bool "Use SRM as bootloader" if ALPHA_CABRIOLET || ALPHA_AVANTI_CH || ALPHA_EB64P || ALPHA_PC164 || ALPHA_TAKARA || ALPHA_EB164 || ALPHA_ALCOR || ALPHA_MIATA || ALPHA_LX164 || ALPHA_SX164 || ALPHA_NAUTILUS || ALPHA_NONAME
depends on TTY
diff --git a/arch/alpha/include/asm/machvec.h b/arch/alpha/include/asm/machvec.h
index 72dbf23..4ac9016 100644
--- a/arch/alpha/include/asm/machvec.h
+++ b/arch/alpha/include/asm/machvec.h
@@ -126,13 +126,19 @@ extern struct alpha_machine_vector alpha_mv;

#ifdef CONFIG_ALPHA_GENERIC
extern int alpha_using_srm;
+extern int alpha_using_qemu;
#else
-#ifdef CONFIG_ALPHA_SRM
-#define alpha_using_srm 1
-#else
-#define alpha_using_srm 0
-#endif
+# ifdef CONFIG_ALPHA_SRM
+# define alpha_using_srm 1
+# else
+# define alpha_using_srm 0
+# endif
+# ifdef CONFIG_ALPHA_QEMU
+# define alpha_using_qemu 1
+# else
+# define alpha_using_qemu 0
+# endif
#endif /* GENERIC */

-#endif
+#endif /* __KERNEL__ */
#endif /* __ALPHA_MACHVEC_H */
diff --git a/arch/alpha/kernel/setup.c b/arch/alpha/kernel/setup.c
index 9e3107cc5..c38d6a1 100644
--- a/arch/alpha/kernel/setup.c
+++ b/arch/alpha/kernel/setup.c
@@ -115,10 +115,17 @@ unsigned long alpha_agpgart_size = DEFAULT_AGP_APER_SIZE;

#ifdef CONFIG_ALPHA_GENERIC
struct alpha_machine_vector alpha_mv;
+#endif
+
+#ifndef alpha_using_srm
int alpha_using_srm;
EXPORT_SYMBOL(alpha_using_srm);
#endif

+#ifndef alpha_using_qemu
+int alpha_using_qemu;
+#endif
+
static struct alpha_machine_vector *get_sysvec(unsigned long, unsigned long,
unsigned long);
static struct alpha_machine_vector *get_sysvec_byname(const char *);
@@ -529,11 +536,15 @@ setup_arch(char **cmdline_p)
atomic_notifier_chain_register(&panic_notifier_list,
&alpha_panic_block);

-#ifdef CONFIG_ALPHA_GENERIC
+#ifndef alpha_using_srm
/* Assume that we've booted from SRM if we haven't booted from MILO.
Detect the later by looking for "MILO" in the system serial nr. */
alpha_using_srm = strncmp((const char *)hwrpb->ssn, "MILO", 4) != 0;
#endif
+#ifndef alpha_using_qemu
+ /* Similarly, look for QEMU. */
+ alpha_using_qemu = strstr((const char *)hwrpb->ssn, "QEMU") != 0;
+#endif

/* If we are using SRM, we want to allow callbacks
as early as possible, so do this NOW, and then
--
1.8.1.4


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